STOCK ASSESSMENT OF WHITE GRUNT FROM THE WEST ...

STOCK ASSESSMENT OF WHITE GRUNT 

FROM THE WEST COAST OF FLORIDA 

Michael D. Murphy 1 , Debra J. Murie 2 , and Robert G. Muller 1 

Report to the Florida Fish and Wildlife Conservation Commission 

October 12, 1999 

____________ 

1 

Florida Marine Research Institute, Florida Department of Environmental Protection, 100 

Eighth Avenue S.E., St. Petersburg, Florida 33701-5095 

2 

Department of Fisheries and Aquatic Sciences, University of Florida, 7922 NW 71 st Street, 

Gainesville, Florida 32653

EXECUTIVE SUMMARY 

• This assessment uses fishery landings and catch-per-unit effort to estimate the average 

fishing mortality and population size for white grunt found along the Atlantic and Gulf coasts 

of Florida. A summary is presented on findings from a recent study of the life history 

characteristics of white grunt in the eastern Gulf of Mexico. These are contrasted with white 

grunt studies conducted for white grunt along the South Atlantic Bight. The estimated 

length-weight relations, age and growth, and maturity schedules are used with estimates of 

fishing mortality to determine the status of white grunt relative to several important 

biological benchmarks used in fisheries assessments (F 0.1 , F 35% , F max ). 

• Commercial landings of white grunts are reported in a composite category of ‘grunts’. 

Samples of commercial landings show that white grunt are often only a small portion of the 

landings made under this category. On the Atlantic coast, annual landings of white grunt 

appears to be less than about 500 pounds. On the Gulf coast, annual commercial landings 

increased from 51,000 pounds in 1986 to over 500,000 pounds in 1994 and have declined 

since, reaching 273,000 pounds in 1998. 

• Most ‘grunts’ landings are reported caught with hook-and-line gear or traps. Species landed 

along with ‘grunts’ landings are those typically found in low- to high-relief areas on the 

shelf, including several groupers, hogfish, snappers, black seabass, octopus, and stone crabs. 

The modal lengths of white grunt landed is 9” or 10” fork length with a weight of about 0.7 

pounds. Occasionally, white grunt as large as 20-30” fork length were landed. 

• Estimated recreational landings for non-head-boat anglers during 1996-1998 averaged 

217,000 fish on the Atlantic coast and 1,655,000 fish on the Gulf coast. The estimated 

number of white grunt released alive was often twice or more the number of white grunt 

landed. Head-boat landings averaged 12,000 white grunt during 1995-1997 on the Atlantic 

coast and 594,000 white grunt on the Gulf coast. The majority of angler-landed white grunt 

ranged 7-9” fork length on the Atlantic coast and 7-12” fork length on the Gulf coast. Grunt 

landed by head-boat anglers averaged about 9” fork length (10” maximum total length). 

• The total harvest of white grunt in Florida has declined since 1992 on the Atlantic coast and 

since 1994 on the Gulf coast. At their peak in 1991-1992, Atlantic coast landings averaged 

about 483,000 fish (303,000 pounds). This dropped to an average of 184,000 fish (101,000 

pounds) during 1995-1997. Total landings on the Gulf coast peaked during 1989-1995 with 

2.9-4.1 million fish landed (2.3-3.1 million pounds) then dropped to 2.5 million fish (1.8 

million pounds) in 1996-1997. 

• White grunt abundance or biomass indices and estimates showed a flat to slight downward 

trend on both coasts of Florida during recent years. Estimated recruitment of white grunt has 

varied without trend since 1994 on the Atlantic coast and since 1987 on the Gulf coast. 

• Estimates of fishing mortality peaked during the early-mid 1990s on both coasts of Florida. 

The 1998 estimates are fishing mortality of white grunt on the Atlantic coast is at or slightly 

2

higher than the fishing mortality needed for yields at F 0.1 and F 35% . Gulf coast estimates are 

below these benchmarks. 

• Overall white grunt populations in Florida are likely to be able to sustain their current levels 

of production (in both biomass from growth and numbers from new recruits) under the 1998 

levels of fishing. Estimated spawning potential ratios ranged 32-35% on the Atlantic coast 

and 43-46% on the Gulf coast. It should be noted that much of the conclusions for Atlantic 

coast white grunt are based on the tenuous assumption used in this assessment that their life 

history characteristics are the same as that for white grunt in the eastern Gulf of Mexico. 

3

INTRODUCTION 

In the southeastern United States, grunts, and in particular white grunt (Haemulon 

plumieri), are important in commercial and recreational fisheries National Marine Fisheries 

Service (NMFS 1998). The majority of both the recreational catch and the commercial catch of 

white grunt in Florida is taken off the west coast in the Gulf of Mexico. 

Currently, white grunt are an unregulated species (no bag- or size-limit) in the 

commercial and recreational fisheries in Florida (Florida Department of Environmental 

Protection 1999). Recently, there has been concern raised regarding the level of fishing pressure 

exerted on white grunt. In 1998, the Marine Fisheries Commission (MFC) began public 

meetings to consider statewide fishing regulations for white grunt that was to include a 12-inch 

(30.5 cm) total length limit and a 20-fish aggregate daily bag limit (MFC 1998). In 1998, 

however, population dynamics for white grunt from Florida, and in particular from the west coast 

of Florida, were unknown. In 1998 and 1999, mortality, age and growth, and reproductive 

studies of white grunt from the west coast of Florida were completed (Murie and Parkyn 1998, 

1999). 

This report presents the first stock assessment for white grunt in Florida. It provides 

details on the biology of white grunt, including comprehensive aging methods, age and growth 

models, reproduction studies emphasizing maturity schedules, spawning periodicity, and sex 

ratios, and total mortality estimates. It also provides an overview of the trends in the recreational 

and commercial fisheries for white grunt in the eastern Gulf of Mexico. We present an 

assessment of the condition of the stock based on data currently available, and provide some 

recommendations on the types of biological and fishery data required for further stock 

assessments. 

I. BIOLOGICAL CHARACTERISTICS 

Various sources of data and information were used to document the biological 

characteristics of white grunt, which have been reviewed by Darcy (1983). There were few 

biological studies of white grunt from the west coast of Florida (Moe 1966, 1967; Murie and 

Parkyn 1998, 1999). Comparative biological information was obtained from studies of white 

grunt from the southeastern United States (Palm Beach County through the Florida Keys) (Potts 

and Manooch In review), the Carolinas (Manooch 1976, Potts and Manooch In review), the 

South Atlantic Bight (primarily northern Georgia and the Carolinas) (Padgett 1997), Puerto Rico 

(Erdman 1956, 1977), Campeche Bank off Mexico (Kapote 1971), and Jamaica (Billings and 

Munro 1974). 

Morphometrics 

Large white grunts greater than 16 inches (>400 mm) total length were not represented in 

fish collections (n=~3,500) from the west coast of Florida (Murie and Parkyn 1998, 1999). Reports 

from fishers indicated that large grunts may occur offshore in deeper water (e.g., the Middle 

Grounds), but this has not been substantiated by voucher specimens. Padgett (1997) reported a 

maximum size of white grunt from the South Atlantic Bight (Georgia and Carolinas) of 485 mm 

(19.1 inches) total length. Manooch (1976) and Potts and Manooch (In review) collected white 

4

grunts off the Carolinas of a maximum size of 589 mm (23.2 inches) and 512 mm (20.1 inches), 

respectively. 

For white grunt collected from the head-boat fishery on the west coast of Florida, the 

relationship between maximum total length (MTL) (inches) or fork length (FL) and weight (lbs) 

showed no difference between males and females and was described by (modified from Murie and 

Parkyn 1998): 

MTL = -0.05 + 1.14FL n = 928 r 2 = 0.99 

Weight = 0.00087 MTL 2.7 n = 930 r 2 = 0.95 

Weight = 0.00114 FL 2.80 n = 926 r 2 = 0.95. 

White grunt from southeastern Florida had a similar weight-length relationship compared 

with white grunt from the west coast of Florida (Fig. 1). In general, however, white grunt collected 

from the Carolinas weighed more at the same length as white grunt from the west coast of Florida. 

Stock Distribution 

White grunt occur from Virginia to Bermuda, in the Gulf of Mexico, through the 

Caribbean, and south to Brazil (Hoese and Moore 1998). Recently, three distinct lineages of 

white grunt have been identified through mitochondrial DNA analysis (Chapman 1998): 1) a 

northern type found from the Carolina’s south to the Florida Keys, and in Panama City, Gulf of 

Mexico; 2) a southern form found in the Florida Keys, Yucatan, Belize and Puerto Rico; and 3) a 

third form found exclusively in Trinidad (Chapman 1998). The possibility exists therefore that the 

considerable growth differences between white grunt from the west coast of Florida (Murie and 

Parkyn 1999) and grunt from the Carolinas (Manooch 1976, Potts and Manooch In review) may, in 

part, have a genetic basis. However, genetic differences presumably do not explain the differences 

in growth observed for white grunt from the South Atlantic Bight (but mainly northern Georgia and 

the Carolinas) (Padgett 1997) and the Carolinas (Manooch 1976, Potts and Manooch In review), 

since the white grunt from both of these areas should be of the northern form (some overlap with the 

southern form may be possible). Preliminary determination of the genetic structure of white grunt 

from St. Petersburg to Steinhatchee, Florida, is currently underway (Murie et al. In progress). 

Habitat Requirements and Distributional Pattern 

Based on tag returns, Moe (1966) concluded that white grunt off the central west coast of 

Florida reside in one general area and do not undertake substantial movements or seasonal 

migrations. Of 39 tagged white grunt recovered in his study, only 5 % (2) were recaptured more 

than 5 miles from their release site (Moe 1966). Springer and McErlean (1962) also found that 

only a small percentage (about 3-4 %) of white grunt off Upper Matecumbe Key in Florida 

displayed any movement, with all fish eventually returning to their original reef. 

On a short-term basis, white grunts off south Florida (Starck and Davis 1966) and off St. 

Croix (Ogden 1977, Ogden and Ehrlich 1977) have been observed to undertake diurnal 

migrations related to foraging. In St. Croix, white grunts, along with other grunt species, leave 

reefs shortly after sunset to forage over grass and sand flats, and then return to the reef 

5

environment before sunrise for shelter. Off the west coast of Florida, the extent of diurnal 

migrations of white grunt are unknown. Information provided by head-boat captains and mates 

indicate that white grunt in the coastal area off Clearwater, Florida, can be caught directly on 

reefs during the night (pers. comm. to DM). Although anecdotal, this may indicate that white 

grunt off the west coast of Florida do not diurnally migrate and rely solely on on-reef production 

for their food resources. 

Food Habits 

White grunt is a generalized carnivore, feeding on a variety of benthic invertebrates. 

Davis (1967) reported white grunt from Alligator Reef in the Florida Keys as having consumed 

polychaetes, crabs, shrimps, isopods, and fish. Juvenile white grunt collected from Crystal River 

and Cedar Key had consumed primarily plankton (copepods, mysids, and postlarval shrimps) 

(Carr and Adams 1973, Reid 1954). 

Food habit studies of white grunt from Puerto Rico, Haiti, and the Virgin Islands indicate 

that adults feed on a variety of shrimps, crabs, polychaetes, snails, sipunculids, amphipods, 

ophiuroids, fishes, tunicates, and echinoderms (Randall 1967, Parrish and Zimmerman 1977, 

Valdés Muñoz and Silva Lee 1977). 

Reproductive Life History 

Female white grunts from the west coast of Florida attained sexual maturity when between 7 

and 10 inches in length, with 50% of females mature at 8 inches (Fig. 2) (Murie and Parkyn 1999). 

All females were sexually mature when ≥10 inches total length (~2-3 years of age). Similarly, 

males reached sexual maturity between 7 and 10 inches, with over 50% of males maturing between 

6 and 7 inches total length (~1-2 years old) (Murie and Parkyn 1999). As with females, all males 

were mature when ≥10 inches total length (Murie and Parkyn 1999). 

Size at maturity for female white grunt from the west coast of Florida was only slightly 

larger than size at maturity for white grunt from the South Atlantic Bight where 50% of the females 

were mature at 6.6 inches (167 mm TL, with a 95% confidence limit of 150-177 mm TL) (Padgett 

1997). Male white grunt from the west coast of Florida were sexually mature at similar size 

compared with males from the SAB, which were mature at 7.3 inches (186 mm TL, 95% CLs of 

173-194 mm TL) (Padgett 1997). 

White grunt from the west coast of Florida spawn once per year, as indicated by the 

frequency of occurrence of the ovarian stages of females and their associated gonadosomatic index 

(Fig. 3, 4) (Murie and Parkyn 1999). The presence of both hydrated and vitellogenic oocytes in 

spawning females, however, indicated that they were batch spawners, with a peak in spawning 

activity in May (Murie and Parkyn 1999). Male grunts from the west coast of Florida spawn during 

April through to September, with a peak in spawning activity during April and May (Fig. 4, 5) 

(Murie and Parkyn 1999). 

Similarly, Padgett (1997) observed that female white grunts on the Atlantic coast spawned 

from March through September with a peak in spawning activity during May and June. The 

maximum gonadosomatic index (GSI = gonad weight/body weight*100%) for females from the 

west coast of Florida (7.8%, Murie and Parkyn 1999) was almost double that of the maximum GSI 

observed for female grunts in the Atlantic (4.5%, Padgett 1997). Male white grunts in the Atlantic 

6

had a peak in spawning activity during March through to June (Padgett 1997) and therefore had a 

similar spawning season as white grunt from the west coast of Florida. 

White grunt south of Florida have been observed spawning by Evermann and Marsh (1902) 

in August and September off Puerto Rico. Erdman (1956, 1977), however, observed ripe white 

grunts off Puerto Rico in the spring (February to April with a peak in March) and in the fall 

(September and November). In Jamaica, white grunt spawn year-round, although there is a 

maximum amount of spawning during March and April (Munro et al. 1973). Billings and Munro 

(1974) similarly observed spawning of white grunt in Jamaica from January through April , but they 

also observed a secondary spawning peak in October and November. The potential for white grunt 

to batch-spawn twice a year was important to consider for fish from the west coast of Florida 

because fishers had reported seeing white grunt with roe in the fall. Murie and Parkyn (1998, 1999) 

only found evidence to support one spawning cycle per year, but multiple year monitoring of the 

spawning cycle may be necessary to observe any secondary spawning peak in the fall that does not 

consistently occur every year. 

Spawning frequency (number of days between sequential spawns) and annual fecundity 

have not been estimated for white grunt from the United States. Fecundity has been estimated 

for white grunt from Jamaica (Billings and Munro 1974) as: 

e = 607w - 93,000, where e = fecundity and w = body weight in grams. 

For white grunt from Port Royal, average fecundity was estimated as 42,000 eggs/female per 

spawning season, with fish of 220 g average weight (Billings and Munro 1974). On unexploited 

reefs of Jamaica (Pedro Bank), fish were an average size of 400 g and were estimated to produce 

150,000 eggs per female per spawning season (Billings and Munro 1974). 

The sex ratio of grunts captured in the head-boat fishery off the west coast of Florida 

during the spawning season was skewed significantly toward males (Murie and Parkyn 1998). 

This indicated that female grunts were less catchable using hook-and-line gear than males during 

the spawning season. In the post-spawning season, the sex ratio of white grunt in the head-boat 

catch was not significantly different from 1:1 (Murie and Parkyn 1998). 

Padgett (1997) noted that the overall sex ratio of white grunt captured in MARMAP 

sampling and in the commercial fishery in the SAB was significantly skewed toward females. 

However, the overall sex ratio was equal among the different age classes of white grunt sampled 

by the different gear types (Padgett 1997). Previous information on the sex ratios of white grunt 

caught in traps in Jamaica indicated that the sex ratio was skewed toward females (Billings and 

Munro 1974). 

Age and Growth 

Age and growth of white grunt from the west coast of Florida has been recently analyzed 

by Murie and Parkyn (1999). Previous to their study, very limited growth rate data (n=5 fish) 

were available for fish from the eastern Gulf of Mexico from tag-recapture studies of Moe (1966, 

1967). In comparison, age and growth of white grunt is known for fish occurring off the Atlantic 

coast of the United States (Manooch 1976, Padgett 1997, Potts and Manooch In review), 

Campeche Bank of Mexico (Kapote 1971), and Jamaica (Billings and Munro 1974). 

Various methods have been used to age white grunt, including scales (Manooch 1976), 

whole sagittal otoliths (Manooch 1976, Murie and Parkyn 1999), and thin-sectioned sagittal 

7

otoliths (Padgett 1997, Murie and Parkyn 1999, Potts and Manooch In review). Alternative 

methods of aging white grunt, including breaking-and-burning sagittal otoliths and thinsectioning 

of fin rays, have also been investigated (Murie and Parkyn 1999). 

Manooch (1976) reported that ages of white grunt read using scales and surface readings 

of whole otoliths agreed 75% of the time for fish 2 to 12 years of age, with most of the 

disagreement occurring in fish 9 to 10 years old. In comparison with sectioned otoliths, whole 

otoliths underestimated the age of white grunts from 0 to 18 years of age after 8-10 years (Murie 

and Parkyn 1999). Percent agreement between whole and sectioned otoliths changed from 91% 

for grunt less than 10 years old to only 14% for fish older than 10 years, with differences between 

ages as high as 4-5 years in older fish (Murie and Parkyn 1999). It was therefore necessary to use 

thin-sectioned otoliths to reliably age white grunt from the eastern Gulf of Mexico. Using this 

method, Murie and Parkyn (1998, 1999) obtained an average estimate of aging precision 

between two independent readers of 98% (n=1,015), with a concordance correlation of 0.997. 

Similar aging precision has been obtained by Padgett (1997) aging white grunt from the South 

Atlantic Bight using sectioned otoliths (97%). 

Aging methodology using sectioned otoliths has only recently been validated for white 

grunt from the eastern Gulf of Mexico, using both marginal-increment analysis and chemical 

marking (Murie and Parkyn 1999). Murie and Parkyn (1999) observed that the mean monthly 

index of completion for the marginal increment (the distance from the last annulus to the margin 

of the otolith as a proportion of the last complete increment) was unimodal (Fig. 6), indicating 

that white grunt in the eastern Gulf of Mexico were depositing only one annulus each year. In 

addition, the index of completion was at a minimum in May and June, which indicated that white 

grunt deposited their annulus during this time period. The formation of one annulus in an 

intervening 12-month period was also confirmed using oxytetracycline as a chemical mark 

injected into white grunts that were subsequently held in captivity for one year (Murie and 

Parkyn 1999). 

Based on marginal-increment analysis, Padgett (1997) and Potts and Manooch (In 

review) have recently determined that white grunt in the Atlantic also deposit one annulus each 

year. In the South Atlantic Bight (primarily northern Georgia and the Carolinas) and the 

Carolinas, white grunt form their annulus in March/April (Padgett 1997 and Potts and Manooch 

In review, respectively). Similar to white grunt from the west coast of Florida, white grunt from 

southeastern Florida form their annulus primarily in May (range of March-June) (Potts and 

Manooch In review). 

White grunt from the west coast of Florida reach a maximum age of 18 years (Murie and 

Parkyn 1998). Both female and male white grunts show very rapid growth in length in their first 

three years, after which their growth slows and plateaus at around 12-13 inches total length (Murie 

and Parkyn 1999) (Fig. 7). Growth curves of female and male white grunt collected from either 

research samples (primarily hook-and-line gear) and the commercial fishery (traps) from the eastern 

Gulf of Mexico were described by von Bertalanffy growth models (Table 1) (modified from Murie 

and Parkyn 1999). Although there was an overall trend in male white grunts being slightly larger 

than females at any age beyond 2 years, especially for males collected in the commercial trap 

fishery, there was also a lot of variability in the growth of grunts (Fig. 7) (Murie and Parkyn 1999). 

Minor differences observed between research and commercial samples were probably due to both 

differences in gear and depth, since the trap fishery operates in >60 feet of water whereas the 

research sampling was carried out in 18-37 feet of water. Padgett (1997) also found that fish 

8

collected from the commercial fishery were larger than grunts collected through research 

(MARMAP) sampling, again possibly due to gear and depth differences. 

Since many fishery statistics are not sex-specific, an overall growth curve (sexes pooled) for 

white grunt from the west coast of Florida was provided by (modified from Murie and Parkyn 

1999): 

Lt 

052 . ( t 0. 58) 

( e ) 

= 1272 . 1− − + 

n = 1,185 

Comparison of the growth of white grunt from the west coast of Florida with previously 

published white grunt growth curves was partially confounded because Manooch (1976) used 

whole sagittal otoliths and scales, the former of which Murie and Parkyn (1999) demonstrated a 

significant bias in underestimating ages. Recently, however, Potts and Manooch (In review) 

have reassessed the age and growth of white grunts from the Carolinas using sectioned otoliths. 

Their recent study corroborates Manooch’s (1976) earlier work. 

Based on pooling growth models of males and females and truncating the growth curves at 

13 years of age for comparative purposes, white grunts from the west coast of Florida (Murie and 

Parkyn 1999) exhibited a similar growth pattern as white grunt from the South Atlantic Bight 

(commercial and recreational samples from Padgett 1997) and southeastern Florida (Potts and 

Manooch In review) (Fig. 8). Padgett (1997) aged white grunt to a maximum of 27 years, whereas 

Potts and Manooch (In review) aged white grunts to only 15 years in southeastern Florida. 

In contrast, the growth curves estimated by Manooch (1976) and Potts and Manooch (In 

review) for white grunt in the Carolinas were fundamentally different than the growth curve 

estimated for white grunt from the west coast of Florida, both in the basic shapes (no defined 

asymptotes obvious), growth coefficients (very low k values of 0.11 and 0.08, respectively), and 

estimated asymptotic lengths [L ∞ = 640 mm (25.2 inches) and 591 mm (23.3 inches), respectively] 

(Fig. 8). Both Manooch (1976) and Potts and Manooch (In review) aged white grunt from the 

Carolinas to a maximum of 13 years. These basic differences in growth rates may be attributed to 

differences in environments (habitat, food base, etc.), mortality, and, more recently, genetics (see 

Stock Distribution section). 

On the Atlantic coast of the United States, the large difference observed between age and 

growth of white grunt from the Carolinas based on the studies by Manooch (1976) and Potts and 

Manooch (In review) and from the SAB (but primarily from northern Georgia and the Carolinas) 

based on the study by Padgett (1997) remains unresolved. 

II. FISHERY CHARACTERISTICS 

Commercial 

Commercial landings of white grunt are reported within the Marine Fisheries Information 

System (Trip ticket) category ‘grunts’ along with several other related species. In order to 

estimate the contribution of white grunt to this aggregate, the contribution of different grunt 

(Family: Haemulidae) species to this category was determined from Trip Interview Program 

(TIP) data. These data showed that white grunt were one of at least eight haemulid species 

reported under this category and that white grunt’s contribution was quite different in different 

9

areas of Florida (Table 2). On the Atlantic coast, the average contribution of white grunts, by 

weight, to the 1992-1998 TIP samples was less than 1%, with no white grunt sampled south of 

Martin county or anywhere on the Atlantic coast prior to 1997 (Table 3). On the Gulf coast, an 

average of about 7% of the TIP samples of grunts made between Gulf and Escambia counties 

were white grunt. From Franklin through Pinellas counties nearly all grunts in the TIP samples 

where white grunt (Franklin county was included in this area even though no TIP samples came 

from this county). The 1992-1998 annual average contribution by weight was 73%(Table 3). 

Further south, the annual average contributions were 9% for Hillsborough through Lee counties 

and 29% for Collier through Monroe counties. These percent contributions were used to 

estimate the annual commercial landings of white grunt within each of these areas for each year 

between 1986 and 1998. The accuracy of these estimates rely on how well the species 

composition of the TIP sample data for haemulid species described the actual species 

composition of the ‘grunt’ trip ticket category. In addition, several weight-length relations taken 

from the literature were used to convert these eight species’ lengths to weights (Bohnsack and 

Harper 1988, Murie and Parkyn 1998). If other non-haemulid species are also landed under this 

category the estimates of white grunt landings will be too high. If white grunt are landed under 

other categories, such as miscellaneous food fish, their estimated landings will be too low. 

Almost all of Florida’s estimated commercial landings of white grunt are made on the 

Gulf coast. Annual Atlantic coast landings were less than 510 pounds during the entire period 

1986-1998 (Table 4, Fig. 9). On the Gulf coast, estimated landings increased from about 51,000 

pounds in 1986 to just over 500,000 pounds in 1994. Since then annual Gulf coast landings have 

declined, reaching 273,000 pounds during 1998. 

The number of commercial trips reporting landings of fish in the ‘grunts’ category has 

increased recently on the Atlantic coast and has fluctuated without a strong trend on the Gulf 

coast. In 1998, nearly 2,500 commercial trips reported landings of grunts on the Atlantic coast 

(Table 5). Of course, based on TIP samples these were mostly landings of pigfish, black margate 

and porkfish. The annual number of Gulf coast commercial trips reporting ‘grunts’ landings 

were about 5,900-6,000 during 1997-98. 

Grunts comprise only a portion of the landings made by most commercial fishing trips 

reporting grunt landings. On the Atlantic coast , only about 20% of the trips reporting grunt 

landings reported at least 50% of their landings as grunts during 1996-98 (Table 5). On the 

Gulf coast, this percentage is about 30%. The species reported landed with white grunt are 

those typically found associated with low to medium relief bottom in the eastern Gulf of Mexico. 

The included gag, red grouper, hogfish, black seabass, lane snapper, vermilion snapper, porgies, 

stone crabs, and octopus (Table 6). 

The number of Saltwater Products license holders reporting annual landings in excess of 

1,000 pounds is only a small segment of the total fishery participants (Table 7). During 1987, 

only 8% of the Atlantic coast SPL holders reported landings at least 1,000 pounds of grunts that 

year. On the Gulf coast only 3% of SPL holders landed this amount of grunts. These rates have 

changed little with 3-8% of the SPL holders landing grunts of at least 1,000 pounds in 1998. 

Most grunt landings come from catches made using hook-and-line gear or traps. Only a 

small portion of the landings were caught by other gears, such as trawl, gill net or gig/spear. In 

1998, twelve percent of the trips reporting landings of grunts on the Atlantic coast reported 

using traps and 58% reported using hook-and-line (Table 8). On the Gulf coast in 1998, 10% 

reported using traps and 84% reported using hook and line. These two gears have been 

responsible for a majority of the landings on either coast for the entire period that these data are 

10

available, 1992-1998. The number of trips reporting landings of grunts made using traps has 

increased on the Atlantic coast and decreased on the Gulf coast. The number of Atlantic coast 

trips using traps increased from 45 in 1992 to 288 in 1998. In contrast, the Gulf coast trips using 

traps fell from 1,225 in 1992 to 593 in 1998. The total annual harvest made by these gear during 

1992-98 also followed these trends. Within the Gulf coast, few commercial trips in the 

Panhandle reported landing grunts with either traps or hook-and-line (Table 6). In the region 

from Wakulla through Pasco county, the numbers of trips reporting landings of grunts using 

hook-and-line gear or using traps was similar during 1992-1995 but has been increasingly 

dominated by hook-and-line gear since then. Despite the increase in hook-and-line trips, the 

number of pounds of ‘grunts’ landed by traps is still greater than that landed by hook-and-line. 

In the Pinellas-Collier region about ten times more trips were made with hook-and-line gear than 

with traps. This gear preference for hook-and-line gear was even more extreme in Monroe 

county during 1996-1998, with 2,000-3,000 hook-and-line trips and about 150 trap trips. 

The annual modal lengths for white grunt sampled from the commercial landings during 

TIP was 9 or 10” fork length for all years except 1994 when it was 12” (Fig. 10). Few white 

grunt were measured on the Atlantic coast but these also showed a modal fork length of 9 or 

10”. Occasional samples contained very large white grunt ranging from 20-30” FL. The modal 

weights of white grunt in the TIP samples were 0.7 and 0.5 pounds in 1997 and 1998, 

respectively, on the Atlantic coast (Fig. 11). On the Gulf coast modal weights were at 0.7 

pounds for both years. 

Recreational 

Marine Recreational Fisheries Statistics Survey (MRFSS) 

Estimated average annual landings of white grunt by non- headboat anglers during 1996- 

98 were about 217,000 fish on the Atlantic coast and 1,655,000 fish on the Gulf coast (Table 9). 

Atlantic coast landings were highly variable ranging from zero in 1988 to 528,000 in 1992. The 

number of white grunt caught and released alive was often similar to the number caught and 

landed (Fig. 12). On the Gulf coast, landings were less variable, with most estimates of annual 

landings during the period 1983-93 at about 2,000,000 fish. An exception to this was a very low 

estimate of 542,000 fish landed in 1986. During the three most recent years (1996-98) landings 

have been less than 2,000,000 fish. The numbers of white grunt released alive was often twice or 

more the number of white grunt landed on the Gulf coast. 

The majority of white grunt landed and sampled by MRFSS creel clerks ranged from 7- 

9” FL on the Atlantic coast and 7-12” on the Gulf coast (Table 10). Some of the very large fish, 

over about 26” FL in the Gulf coast data from MRFSS may be margate lengths instead of those 

of white grunt that are not known to get this large. 

Of the anglers who caught white grunt, few indicated to MRFSS creel clerks that they 

had been targeting white grunt. During the period 1982-1998, only 14 of 1,058 (1.3%) Atlantic 

angler-respondents said that they were fishing specifically to catch white grunts (Table 11). On 

the Gulf coast during this period only 3.8% (178/4372) anglers responded that they were fishing 

for white grunt. The estimated number of trips taken by anglers fishing from private or rental 

boats and targeting or catching white grunt was highest in the early 1990s on both coasts (Fig. 

13). The number of fishing trips has varied around 100,000 trips on the Atlantic coast over the 

11

1986-1998 time frame. On the Gulf coast the number of trips dropped from about one million 

during 1994 and 1995 to 650,000 in 1997 and 1998. 

Angler landings of white grunt do not vary significantly in any seasonal pattern. Using 

the two-month period estimates of landings made by MRFSS showed that the relative 

contribution to the annual landings during each of these periods remained about equal (Fig. 14). 

There was a slight increase in the median relative landings in July-August on both coasts for the 

period 1986-98 but this seasonal change was highly variable. 

Head-boat Survey 

The estimates of head-boat angler landings during 1989-1997 were less than 10% of the 

MRFSS annual recreational landings estimates for the Atlantic coast and about 20-25% of the 

these estimates for the Gulf coast. Head-boat landings on the Atlantic coast averaged about 

12,000 white grunt during 1995-97; on the Gulf coast this average was about 594,000 white 

grunt (Table 12, Fig. 15). 

Female white grunt captured in the head-boat fishery off the west coast of Florida during 

the spawning season were on average 10.4 ± 0.9 inches MTL, n=465 (Mean ± 1SD), with fish 

ranging in size from 7.4-12.6 inches (Fig. 16)(Murie and Parkyn 1998). Approximately 2% of 

females were greater than 12 inches total length, and 72% were greater than 10 inches total 

length. Mean maximum total length of male white grunt during the spawning season was 10.6 ± 

1.2 inches, n=556 (Mean ± 1SD), with fish ranging from 7.5-15.1 inches (Fig. 16). 

Approximately 10% of the males sampled from the head-boats were greater than 12 inches total 

length and 68% were greater than 10 inches total length. 

Post-spawning female white grunt were on average 10.5 inches maximum total length 

(± 0.9 inches, n=536) (Mean ± 1SD), with fish ranging in size from 8.2 to 13.1 inches (Murie 

and Parkyn 1998) (Fig. 16). Approximately 2% of females were greater than 12 inches total 

length and 77% were greater than 10 inches total length. Mean maximum total length of postspawning 

male white grunts was 11.0 ± 1.1 inches, n=573 (Mean ± 1SD), with fish ranging from 

8.1-14.2 inches (Fig. 16). Approximately 17% of the post-spawning males sampled from the 

head-boats were greater than 12 inches total length and 84% were greater than 10 inches total 

length. 

Age classes 2 through 4 dominated the head-boat catch from the west coast of Florida for 

both females and males during the spawning and post-spawning seasons (Fig. 17) (Murie and 

Parkyn 1998). Maximum ages of female and male white grunt collected from the head-boat 

fishery was 18 years and 15 years, respectively. Age-class strength was heterogeneous in the 

head-boat fishery. In particular, age class 3 (1995 year class) and age class 5 (1993 year class) 

were consistently poorly represented in the catch relative to age class 4 (1994 year class), which 

appeared to be consistently over-represented in the catch. 

Preliminary estimates of the size of white grunt discarded at sea from the head-boat 

fishery off the west coast of Florida indicated that the fish were mostly in age class 2 (95%). 

Discarded males of age 2 were on average 8.7 ± 0.7 inches total length (Mean ± 1SD) (n=37). 

Age 2 discarded females were on average 8.6 ± 0.5 inches total length (n=19). Average sizes of 

age 2 white grunts kept and landed by customers, however, were 9.4 ± 0.4 inches MTL for males 

(n=11) and 9.4 ± 0.5 inches MTL for females (n=7). Discarded age 2 white grunts were 

significantly smaller than age 2 white grunts landed in the fishery. Selective removal of the 

12

largest individuals in a cohort (age 2 in this case) could have long term effects on the size of 

white grunts caught in the head-boat fishery through selective survival of the smaller, slowergrowing 

individuals in the cohort. 

There were various factors that determined the size of grunt that was to be discarded by 

head-boat fishers. From discussions with mates from various head-boats, in combination with 

sampling from two trips, it was evident that the minimum size of grunt retained was not solely 

determined by the mate’s advice onboard, but rather by the individual paying customer. Most 

mates tended to discourage customers from retaining grunts less than about 9-10 inches, although 

some customers keep every grunt they catch regardless of size. On the other hand, some 

customers discard white grunts that are about 9-10 inches in length or give them to other 

customers that are fishing. These latter customers tend to be concentrating on catching grouper 

rather than grunts. 

Total Harvest 

The total harvest for white grunts appears to have declined since about 1992 on the 

Atlantic coast and since 1994 on the Gulf coast. Data on landings of white grunt are available 

for all three components of the fishery during the period 1989-97. This is the period when headboat 

landing estimates are available. On the Atlantic coast, white grunt landings averaged about 

483,000 fish (303,000 lbs) at their peak in 1991-92 (Fig. 18). Total landings then dropped to an 

annual average of 184,000 fish (101,000 lbs) during 1995-97. In 1998 recreational and 

commercial landings totaled 292,000 fish (179,000 pounds). On the Gulf coast, white grunt 

landings ranged between 2.9 and 4.1 million fish (2.3-3.1 million pounds) during the period 

1989-1995 (Fig. 19). During 1996 and 1997 average annual landings dropped to 2.5 million fish 

and 1.8 million pounds. In 1998 the total recreational and commercial landings were lower than 

that for any year during 1989-1997. It needs to be noted that release mortality was not factored 

into our estimates of the total harvest. This was because there is no information on mortality 

rates for released white grunt or for the sizes of released fish. 

Average weights of white grunt sampled from the three components of the fishery 

showed larger white grunt landed by the commercial fishery on the Atlantic coast and by the 

recreational and headboat fisheries on the Gulf coast (Fig. 20). 

III. ASSESSMENT 

A thorough assessment of white grunt populations off Florida cannot be conducted until 

the age composition of the catch has been estimated over a number of years. However, it is 

possible to use available fishery-dependent indices of abundance and estimates of total catch and 

landings to estimate recruitment, abundance, and average fishing mortalities for white grunt. 

Here we report on estimates made using a modified-DeLury population model and the ASPIC 

model for these data for the period 1986-1998. The former model provides estimates of the 

numbers of recruits needed each year and the initial white grunt population abundance needed to 

coincide well with the observed catch and abundance indices. The ASPIC model is a biomass 

dynamic model that estimates the productivity of a stock based on changes in indices of biomass 

as the population is fished. The following sections provide population parameters estimated 

using both these methods and a comparison of the model fits to observed data. 

13

Trends in Abundance 

While several estimates of catch rates were available for the head-boat fishery and the 

commercial fishery, we felt that only the 1982-1998 MRFSS total-catch rates were likely to be 

accurate indices of white grunt abundance. The head-boat catch rates included only white grunt 

landed and kept. The commercial catch rates were also only for landed fish and were designated 

for the composite category ‘grunts’. The abundance indices estimated from MRFSS anglerintercept 

data were GLM indices. These were adjusted for annual effects of changes in county of 

the fishing trip, number of anglers fishing each trip, and number of hours fished on each coast. 

Only those anglers who fished from a private or rental boat were included in the analyses. 

White grunt abundance or biomass indices and estimates showed a flat to downward 

trend on both coasts of Florida in recent years. On the Atlantic coast, the MRFSS index of 

abundance showed a slow decrease since 1986 (Fig. 21). Modified DeLury model results fit this 

pattern well with an estimated average abundance of 1.7-1.9 million fish in 1986 dropping to 

about 0.9-1.1 million fish by 1993 and continuing at an average of about 1.0 million fish through 

1998 (Fig. 22). The estimated average annual biomass relative to the biomass at maximum 

sustainable yield (MSY) was used as the most robust estimate an index of population size from 

the ASPIC model. This ratio also dropped, by 55%, between 1986 and 1993 then remained 

stable at about 1.6 through 1998 (Fig. 23). On the Gulf coast, the MRFSS index of abundance 

showed an increase between 1982 and 1987 then a slow decline through about 1993 followed by 

a steady level through 1998. The modified DeLury model estimates of abundance for white 

grunt increased between 1986 and 1988, reaching a peak of 16.3 million fish during 1987 (Fig. 

22). Abundance then declined slowly to about 12.5-13.0 million fish in 1993 and has slowly 

been steady or increased slightly since then. The ASPIC model biomass ratio estimates also 

showed this same trajectory, with an 19% increase between 1986 and 1988 and drop back to 

1986 levels by about 1996 (Fig. 23). 

Mortality estimates 

Natural mortality can not be estimated directly for white grunt from the eastern Gulf of 

Mexico (or elsewhere in the United States) because white grunt are commercially and 

recreationally fished throughout their geographical range, or have recently been fished even if 

they are now residing in protected areas. In this assessment we assumed a constant 

instantaneous natural mortality rate (M) of 0.2 per year based on the estimated M = 3.0 / 

maximum age. Potts and Manooch (In review) found a maximum age of 15 years for southeast 

Florida white grunt and Murie and Parykn (1999) found a maximum of 18 years. If Padgett’s 

(1997) estimated maximum age of 27 years is correct then the estimated natural mortality may be 

too high. 

Grunts were recruited into the head-boat fishery when in age class 2 (Murie and Parkyn 

1998). Instantaneous total mortality (Z) based on catch-curve analysis did not differ among 

spawning females, spawning males, post-spawning females, and post-spawning males (Murie 

and Parkyn 1998). A pooled catch curve of log e catch as a function of age class estimated Z to be 

0.357 (r 2 =0.73), with a 95% confidence range of 0.284 to 0.430. A point estimate of total annual 

mortality (A) for white grunts was therefore estimated as 0.300, with a 95% confidence limit 

range of 0.247 to 0.349. 

14

Similarly, point estimates of annual mortality rate for white grunt caught in the head-boat 

fishery calculated using Robson and Chapman’s (1961) estimation procedure were 0.280 and 

0.303 for spawning and post-spawning females, respectively, and 0.376 and 0.375 for spawning 

and post-spawning males, respectively (Murie and Parkyn 1998). Hence total annual mortality 

for female grunts based on Robson and Chapman’s estimates were within the 95% confidence 

interval calculated using regression analysis, but for males the estimates based on Robson and 

Chapman’s method were slightly greater than the upper confidence limit of the catch-curve 

analysis. 

Manooch (1976) estimated mean total mortality for white grunts from North Carolina and 

South Carolina in the 1970’s to be between 37 and 51%, slightly greater than the total mortality 

range for white grunts in the Gulf in 1998 (range of 28 to 38 %). The catch curve that Manooch 

(1976) used to calculate total mortality for white grunts from the Carolinas was fundamentally 

different than the catch curve for white grunts in the Gulf of Mexico (Murie and Parkyn 1998). 

In particular with regard to total mortality estimates, Manooch (1976) did not have white grunts 

fully recruited into the head-boat fishery until they were age 7, and the oldest fish that was aged 

in his study was age 13. 

Both of the methods used to estimate survival rate, and hence mortality rate, of white 

grunts in the Gulf are based on the underlying assumptions that for the age classes in the 

analysis: 1) survival rate is uniform with age, and hence mortality rate is uniform with age; 2) 

mortality rate has not changed with time; 3) all ages represented in the analysis have been 

sampled randomly (i.e., they are equally vulnerable to the sampling gear); and 4) recruitment is 

constant for all year classes (Ricker 1975). It was readily apparent that white grunts may have 

undergone significant changes in recruitment among year classes. This was especially evident 

with age class 5, which was the 1993 year class, because it was poorly represented in both 

females and males. Although the mechanism(s) involved in producing a weak or strong year 

class are unknown and difficult to evaluate (i.e., spawning failure, differential recruitment, 

density-dependent mortality, etc.), trends in year class strengths can be effectively assessed 

through cohort survivorship curves by obtaining catch curves over a series of years or, 

alternatively, by a tag-recapture program (Robson and Chapman 1961, Krebs 1989). 

Annual estimates of average fishing mortality for white grunt (made using the modified 

DeLury models) peaked during the early to mid 1990s on both coasts. On the Atlantic coast, 

average instantaneous fishing mortalities peaked at 0.47-0.49 per year in 1992 then decreased 

through 1995 but has increased since (Fig. 24). The range of estimates for instantaneous fishing 

mortality in 1998 was 0.25-0.28 per year. On the Gulf coast, the peak in fishing mortality 

occurred in 1994 or 1995 when F reached about 0.30 per year (Fig. 24). Since then fishing 

mortality has declined reaching about 0.18 per year in 1998. Given an estimate of M equal to 

0.2 per year, the Murie and Parkyn (1998) estimate of total mortality would represent 

instantaneous fishing mortalities (F) ranging 0.08-0.23 per year for Gulf coast populations of 

white grunt. Similarly, the Manooch (1976) estimate of total mortality for the Atlantic coast 

grunt population would represent Fs ranging from 0.26-0.51 per year. 

The estimated average F relative to F MSY (fishing mortality at maximum sustainable 

yield) showed the same patterns seen for the absolute estimates of F (modified DeLury 

estimates). The estimated ratios of F/ F MSY are much more precise than are the absolute 

estimates of F made using the biomass dynamic model ASPIC (Prager 1994). 

15

Recruitment 

The FWC’s Fishery Independent Monitoring (FIM) program does not sample large 

numbers of white grunt in its estuarine-based stratified random sampling program . No white 

grunt juveniles were sampled on the Atlantic coast but a few were captured on the Gulf coast. 

All GLM indices or young-of-the-year white grunt abundance were not significantly different 

from zero except for the estimate for the 1996 year-class (Fig. 25). 

Estimated recruitment (DeLury model) increased between 1987 through 1994 on the 

Atlantic coast but varied without trend since then (Fig. 26). On the Gulf coast, recruitment was 

greatest in 1987 then varied without trend. 

Spawning Potential Ratio 

The static spawning potential ratios estimated for 1998 fishing mortalities were about 32- 

35% on the Atlantic coast and 43-46% on the Gulf coast. Both of these estimates use life history 

information gathered from the eastern Gulf of Mexico and average fishing mortalities estimated 

for populations on each coast. More information is needed on the growth and maturation of 

white grunt on the Atlantic coast of Florida before an independent SPR estimate can be made for 

that population. Padgett (1997) indicates that the 1992 spawning stock ratio per recruit (=SPR) 

for white grunt in the South Atlantic Bight was 19%, possibly indicating a bias in our SPR 

estimates for the Atlantic coast population. 

Present and Future Condition 

White grunt are being fished near or below several important biological reference points 

and well below the fishing mortality at maximum yield. On the Atlantic coast, it appears that 

white grunt are being fished near or at slightly greater levels than that associated with F 0.1 and 

F 35% (Fig. 27). On the Gulf coast, the 1998 fishing mortality estimates are less than that needed 

to give yields at F 0.1 or F 35% . 

Overall the white grunt populations in Florida waters are likely to be able to sustain their 

current levels of production (in both biomass from growth and in production of new recruits) 

under the current levels of fishing. It should be noted that our use of Gulf coast life history 

characteristics for Florida’s Atlantic coast population may make our assessment of that 

population’s condition inaccurate. 

IV. MANAGEMENT 

History of management 

There has been no direct regulation of the harvest of white grunt. 

Bag limit analysis 

A bag-limit analysis conducted on MRFSS data for the period 1993-1998 showed that 

relative large bag-limits could reduce landings by 10%. On the Atlantic coast, a bag-limit of 20 

fish reduced the catch about 3% whereas a bag limit of 10 reduced the catch 12% (Table 13). 

16

Greater reductions in landings occurred on the Gulf coast where a 20-fish bag-limit reduced 

landings by 6% and a 10-fish bag-limit reduced landings by 19% (Table 14). On the Atlantic 

and Gulf coasts less than 2% of the anglers caught more than 20 white grunt. 

V. RESEARCH NEEDS 

Depending on the resolution needed by managers for determining the effects of fishing on white 

grunt stocks in Florida, we will need: 

Low resolution 

Better information on stock structure given the current level of uncertainty in the South Atlantic 

Bight region. 

General life history characteristics of the Atlantic coast white grunt group. 

Medium resolution (current level) 

Better estimates of the commercial catch of white grunt 

Better area- and time-specific length weight relations. 

High resolution 

Age and sex composition of the catch 

Fishery-independent indices of abundance and recruitment 

Evaluating size-limits requires a high resolution of white grunt population dynamics and their 

changes with management. Bag-limit and seasonal-closures require a medium level of 

resolution. 

ACKNOWLEDGEMENTS 

We thank Jennifer Potts and Charles Manooch (NOAA, Beaufort, NC) for providing access to their 

manuscript while In review. Thanks also to Daryl Parkyn (University of Florida) for providing 

access to unpublished data from manuscripts in preparation. 

17

LITERATURE CITED 

Billings, V.C., and J.L. Munro. 1974. The biology, ecology and bionomics of Caribbean reef 

fishes: Pomadasyidae (grunts). Res. Rep. Zool. Dept. Univ. West Indies 3: 1-128. 

Bohnsack, J.A. and D.E. Harper. 1988. Length-weight relationships of selected marine reef 

fishes from the southeastern United States and Caribbean. NOAA NMFS-Tech. Memo. 215. 

Carr, W.E.S., and C.A. Adams. 1973. Food habits of juvenile marine fishes occupying seagrass 

beds in the estuarine zone near Crystal River, Florida. Trans. Am. Fish. Soc. 102: 511-540. 

Chapman, R.W. 1998. Identification of stock structure in black sea bass and white grunt in the 

South Atlantic Coast and Gulf of Mexico. 11 th Annual Marine Fisheries Initiative (MARFIN) 

Conference, December 9-10, Tampa, Florida. 

Darcy, G.H. 1983. Synopsis of biological data on the grunts Haemulon aurolineatum and H. 

plumieri (Pisces: Haemulidae). NOAA Tech. Report NMFS Circular 448. 37 pp. 

Davis, W.P. 1967. Ecological interactions, comparative biology and evolutionary trends of 

thirteen pomadasyid fishes of Alligator Reef, Florida Keys. Ph.D. Thesis, Univ. Miami. 

128 pp. (Cited from Darcy 1983). 

Erdman, D.S. 1956. Recent fish records from Puerto Rico. Bull. Mar. Sci. Gulf Carib. 6: 315- 

340. 

Erdman, D.S. 1977. Spawning patterns of fish from the northeastern Caribbean. Pages 145- 

169 in Cooperative investigations of the Caribbean and adjacent regions—II. Caracas, 

Venezuela (12-16 July 1976). Edited by H.B. Stewart, Jr. FAO Fish. Rep. 200. (Cited 

from Darcy 1983). 

Evermann, B.W., and M.C. Marsh. 1902. The fishes of Porto Rico. Bull. U.S. Fish. Comm. 20, 

Part I. 1900: 49-350. (Cited from Darcy 1983). 

Florida Department of Environmental Protection. 1999. Saltwater fishing regulations. January 

1999 brochure. 

Hoese, H.d., and R.H. Moore. 1998. Fishes of the Gulf of Mexico, Texas, Louisiana, and adjacent 

waters, 2 nd ed. Texas A&M University Press, College Station, Texas. 422 pp. 

Kapote, A.M. 1971. One the age of the main commercial bottom fishes of Campeche Bank. [In 

Russian]. Pages 77-81 in Soviet-Cuban fishery investigations, No. 3. Edited by A.S. 

Bogdanov. Moscow. (Cited from Darcy 1983). 

Krebs, C.J. 1989. Ecological methodology. Harper & Row, New York. 654 pp. 

18

Manooch, C.S., III. 1976. Age, growth and mortality of the white grunt, Haemulon plumieri La 

Cépède (Pisces: Pomadasyidae), from North Carolina and South Carolina. Proc. Annu. Conf. 

Southeast Assoc. Fish Wildl. Agencies 30: 58-70. 

Marine Fisheries Commission (MFC). 1998. Marine Fisheries Commission News Release, 21 

April 1998, for a public meeting on 1-3 June 1998 in Desting, Florida. Agenda Item No. 8 

under “Red Snapper/Other Reef Rish” in News Release. 

Moe, M.A., Jr. 1966. Tagging fishes in Florida offshore waters. Florida Board Conserv. Mar. 

Lab., Tech. Ser. No. 49. 40 pp. 

Moe, M.A., Jr. 1967. Prolonged survival and migration of three tagged reef fishes in the Gulf of 

Mexico. Trans. Am. Fish. Soc. 96: 228-229. 

Munro, J.L., V.C. Gaut, R. Thompson, and P.H. Reeson. 1973. The spawning season of Caribbean 

reef fishes. J. Fish Biol. 5: 69-84. 

Murie, D. and D. Parkyn. 1998. Total mortality of white grunt in the eastern Gulf of Mexico 

using catch-curve analysis. Final Report to the Florida Department of Environmental Protection 

under P.O.# S 3700 831415 to the Florida Marine Research Institute, St. Petersburg. 28pp. 

Murie, D.J., and D.C. Parkyn. 1999. Age, growth, and sexual maturity of white grunt in the eastern 

Gulf of Mexico: Part II. Final Report to the Florida Dept. of Environmental Protection under 

P.O.# S 3700 831415 to the Florida Marine Research Institute, St. Petersburg, FL. 57 pp. 

NMFS (National Marine Fisheries Service). pers. comm. 1998. NMFS Fisheries Statistics & 

Economics Division. Commercial and recreational fisheries statistics surveys via the internet. 

Ogden, J.C. 1977. Behaviour and ecology of schooling groups of juvenile grunts (Pomadasyidae). 

Pages 323-332 in Cooperative investigations of the Caribbean and adjacent areas—II. Caraca, 

Venezuela (12-16 July 1976). Edited by H.B. Stewart, Jr. FAO Fish. Rep. 200. 

Ogden, J.C., and P.R. Ehrlich. 1977. The behavior of heterotypic resting schools of juvenile grunts 

(Pomadasyidae). Mar. Biol. 42: 273-280. 

Padgett, S.M. 1997. Age, growth, and reproductive biology of the white grunt, Haemulon plumieri, 

along the southeast Atlantic Coast of the United States. Masters thesis, University of 

Charleston, South Carolina. 

Parrish, J.D., and R.J. Zimmerman. 1977. Utilization by fishes of space and food resources on an 

offshore Puerto Rican coral reef and its surroundings. Pages 297-303 in Proc. Third Int. Coral 

Reef Symp., Univ. Miami. 

Potts, J.C., and C.S. Manooch III. In review. Differences in age and growth of white grunt from 

North Carolina and South Carolina compared with southeast Florida. Bull. Mar. Sci. 

19

Prager, M.H. 1994. A suite of extensions to a nonequilibrium surplus-production model. Fish. 

Bull. 92:374-389. 

Randall, J.E. 1967. Food habits of reef fishes of the West Indies. Stud. Trop. Oceanogr. (Miami) 

5: 665-847. 

Reid, G.K., Jr. 1954. An ecological study of the Gulf of Mexico fishes, in the vicinity of Cedar 

Key, Florida. Bull. Mar. Sci. Gulf Carib. 4: 1-94. 

Ricker, W.E. 1975. Computation and interpretation of biological statistics in fish populations. 

Fisheries Research Board of Canada Bulletin 191. 

Robson, D.S., and D.G. Chapman. 1961. Catch curves and mortality rates. Trans. Am. Fish. Soc. 

90: 181-189. 

Springer, V.G., and A.J. McErlean. 1962. Seasonality of fishes on a south Florida shore. Bull. 

Mar. Sci. Gulf Carib. 12: 39-60. 

Starck, W.A., II, and W.P. Davis. 1966. Night habits of fishes of Alligator Reef, Florida. 

Ichthyol. Aquarium J. 38: 313-356. 

Valdés Muñoz, E., and A.F. Silva Lee. 1977. Alimentacion de los peces de arrecifes artificales 

en la plataforma suroccidental de Cuba. [In Spanish., English summary]. Acad. Cienc. 

Cuba Inf. Cient-Técn. 24. 21 pp. (Cited from Darcy 1983). 

20

Table 1. Parameter estimates for von Bertalanffy growth models fit to absolute age and size data for white grunts from 

the west coast of Florida (L ∞ in inches) (modified from Murie and Parkyn 1999). 

Sex Gear n Parameter Estimate SE 

Female Research 208 L ∞ 12.51 0.18 

t 0 -0.59 0.15 

k 0.47 0.04 

Female Commercial 326 L ∞ 13.25 0.47 

t 0 -2.20 0.45 

k 0.28 0.05 

Male Research 276 L ∞ 12.97 0.22 

t 0 -0.28 0.11 

k 0.58 0.04 

Male Commercial 375 L ∞ 16.12 0.98 

t 0 -1.29 0.30 

k 0.27 0.05 

Both Pooled 1,185 L ∞ 12.72 0.12 

t 0 -0.58 0.09 

k 0.52 0.03 

21

Table 2. Total numbers and total estimated weights of grunt species sampled from the commercial catch by TIP in 

seven Florida regions during 1992-1998. The proportions of the regional totals over the entire period that were 

white grunt are given for numbers and weight in the last row of the table. 

Species 

Nassau- 

Brevard 

Indian R.- 

Martin 

Palm 

Beach – 

Dade 

Monroe- 

Collier 

Lee- 

Manatee 

Pinellas- 

Franklin 

Gulf- 

Escambia 

Tomtate 

white grunt 

Margate 

ceasar grunt 

French grunt 

bluestriped 

grunt 

Sailors choice 

Pigfish 

black margate 

Porkfish 

Proportion 

that are white 

grunt 

No. Wt. No. Wt. No. Wt. No. Wt. No. Wt. No. Wt. No. Wt. 

0 0 11 2.5 0 0 0 0 0 0 0 0 0 0 

1 1.9 20 10.8 0 0 227 122 1 1.1 3701 2479 1 3.4 

45 80.6 13 14.7 0 0 38 70.3 21 197 95 610 1 5.2 

0 0 0 0 0 0 1686 684 0 0 0 0 0 0 

0 0 0 0 2 2.6 0 0 0 0 0 0 0 0 

0 0 5 2.1 0 0 106 54.5 0 0 7 41.1 0 0 

2 3.2 42 23.5 0 0 6 6.1 0 0 0 0 0 0 

129 78.2 344 157 3 1.6 0 0 9 4.7 306 150 25 14.0 

2 1.1 241 188 1 1.4 0 0 0 0 3 32.3 0 0 

2 0.7 223 117 1 1.1 13 9.5 0 0 0 0 0 0 

0.01 0.01 0.02 0.02 0 0 0.11 0.13 0.03 0.01 0.90 0.75 0.04 0.15 

22

Table 3. Total weight of each year’s TIP samples of white grunt and of all grunts within each region. The 

percentage of the total grunt biomass in each year’s sample that were white grunt was averaged to give an estimate 

of the annual weight contribution of white grunt to the MFS’ ‘grunts’ category. 

Nassau-Brevard counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 0 0 0 0 0 1.89 

Annual 

average 

Total grunts 2.00 8.92 56.76 37.51 21.36 39.12 

Percentage 

white grunt 

0.00% 0.00% 0.00% 0.00% 0.00% 4.84% 0.81% 

Indian River – Martin counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 0 0 0 0 0 2.46 8.31 

Annual 

average 

Total grunts 53.20 12.35 71.14 1.76 3.30 72.34 301.18 

Proportion 

white grunt 

0.00% 0.00% 0.00% 0.00% 0.00% 3.40% 2.76% 0.88% 

Palm Beach – Dade counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 0 0 

Annual 

average 

Total grunts 5.08 1.59 

Proportion 

white grunt 

0.00% 0.00% 0.00% 

Monroe – Collier counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 2.47 68.56 0 6.89 42.13 0 1.56 

Annual 

average 

Total grunts 2.47 91.03 88.30 103.95 215.61 184.60 259.80 

Proportion 

white grunt 

100.00% 75.32% 0.00% 6.63% 19.54% 0.00% 0.60% 28.87% 

23

Table 3 (con’t). Total weight of each year’s TIP samples of white grunt and of all grunts within each region. The 

percentage of the total grunt biomass in each year’s sample that were white grunt was averaged to give an estimate 

of the annual weight contribution of white grunt to the MFS’ ‘grunts’ category. 

Lee – Manatee counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 1.09 0 0 0 0 0 

Annual 

average 

Total grunts 5.79 21.03 81.81 29.86 49.58 15.01 

Proportion 

white grunt 

18.83% 0.00% 0.00% 0.00% 0.00% 0.00% 3.14% 

Hillsborough – Franklin counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 237.65 498.07 177.87 30.47 208.75 252.53 1073.1 

Annual 

average 

Total grunts 452.30 725.03 246.55 172.27 309.93 322.28 1083.6 

Proportion 

white grunt 

52.54% 68.70% 72.14% 17.69% 67.35% 78.36% 99.03% 65.12% 

Gulf - -Escambia counties 

1992 1993 1994 1995 1996 1997 1998 

White grunt 3.42 0 0 

Annual 

average 

Total grunts 9.60 7.80 5.22 

Proportion 

white grunt 

35.63% 0.00% 0.00% 11.88% 

24

Table 4. Annual commercial landings (lbs) of ‘grunts’ and estimates of white grunt landings within regions of 

Florida on the Atlantic and Gulf coast during 1986-1998. 

Atlantic coast 

Nassau - Brevard Indian R. – Martin Palm Beach - Dade Atlantic coast 

White 

White 

White 

White 

grunts grunt grunts grunt grunts grunt grunts grunt 

1986 2,423 20 5,303 47 23,700 0 31,426 67 

1987 12,504 101 5,246 46 57,389 0 75,139 147 

1988 10,752 87 1,334 12 45,132 0 57,218 99 

1989 7,152 58 4,256 37 37,025 0 48,433 95 

1990 3,151 26 6,316 56 77,316 0 86,783 82 

1991 4,743 38 13,915 122 67,365 0 86,023 160 

1992 3,273 27 4,973 44 30,052 0 38,298 71 

1993 1,972 16 6,400 56 28,406 0 36,778 72 

1994 8,105 66 12,683 112 27,364 0 48,152 178 

1995 19,050 154 13,874 122 44,474 0 77,398 276 

1996 21,979 178 34,120 300 29,996 0 86,095 478 

1997 15,208 123 43,653 384 57,910 0 116,771 507 

1998 1,972 16 24,589 216 46,569 0 73,130 232 

25

Table 4 (con’t). Annual commercial landings of ‘grunts’ and estimates of white grunt landings within regions of 


Gulf coast 

Monroe - Collier Lee - Manatee Pinellas - Franklin Gulf - Escambia 

White 

White 

White 

White 

grunts grunt grunts grunt grunts grunt grunts grunt 

1986 81,720 23,593 19,104 600 41,912 27,293 8 8 

1987 108,658 31,370 17,821 560 53,718 34,981 16 16 

1988 106,047 30,616 13,605 427 76,769 49,992 417 417 

1989 91,594 26,443 12,869 404 182,100 118,584 281 281 

1990 70,019 20,214 11,045 347 388,091 252,725 3,497 3,497 

1991 66,473 19,191 17,195 540 657,881 428,412 470 470 

1992 58,134 16,783 14,705 462 547,438 356,492 361 361 

1993 49,992 14,433 14,217 446 698,428 454,816 622 622 

1994 61,615 17,788 13,603 427 745,671 485,581 3,363 3,363 

1995 66,944 19,327 21,457 674 539,472 351,304 766 766 

1996 81,916 23,649 4,482 141 345,986 225,306 958 958 

1997 127,363 36,770 7,020 220 301,558 196,375 17 17 

1998 81,994 23,672 7,358 231 381,765 248,605 108 108 

26

Table 4 (con’t). Annual commercial landings of ‘grunts’ and estimates of white grunt landings within regions of 


Gulf coast 

Gulf coast 

grunts 

White grunt 

1986 142,744 51,487 

1987 180,213 66,913 

1988 196,838 81,085 

1989 286,844 145,464 

1990 472,652 273,701 

1991 742,019 448,199 

1992 620,638 373,780 

1993 763,259 469,769 

1994 824,252 504,196 

1995 628,639 371,396 

1996 433,342 249,210 

1997 435,958 233,367 

1998 471,225 272,521 

27

Table 13. Bag-limit analysis for white grunt using MRFSS interview data for anglers keeping 

white grunt during their fishing trips in Florida Atlantic coast waters. The simulation used data 

for the period 1993-1998 and even numbered bag-limits from 2 to 20 fish. 

FISH AND WILDLIFE CONSERVATION COMMISSION 

FLORIDA MARINE RESEARCH INSTITUTE 

FISHERIES STATISTICS SECTION 

BAG LIMIT ANALYSIS 

SPECIES : WHITE GRUNT MRFSS DATA : 1993 - 1998 ONLY 

COAST : Atlantic 

DATA SOURCE : NMFS Marine Recreational Fisheries Statistical Survey 

********** BASED ON FISH KEPT *********** 

___________________________________________________________________________________________________________________________________ 

Cumulative 

Cumulative 

Number of Fish Number of Number of Number of Average Number of Percentage Number of Fish Percentages of Fish 

Kept per Angler Years Trips Anglers Anglers per Trip of Anglers Caught Retained Caught Retained 

___________________________________________________________________________________________________________________________________ 

0 6 340 370 1.09 41.53 1136 8 33.30 0.40 

1 6 86 148 1.72 58.14 149 125 37.67 6.66 

2 6 82 130 1.59 72.73 294 245 46.29 18.92 

3 6 39 50 1.28 78.34 212 147 52.51 26.28 

4 6 46 62 1.35 85.30 314 248 61.71 38.69 

5 6 25 29 1.16 88.55 145 145 65.96 45.95 

6 5 18 29 1.61 91.81 173 172 71.03 54.55 

7 2 2 4 2.00 92.26 27 27 71.83 55.91 

8 4 9 16 1.78 94.05 138 124 75.87 62.11 

9 2 4 10 2.50 95.17 96 86 78.69 66.42 

10 4 11 17 1.55 97.08 168 168 83.61 74.82 

11 1 1 2 2.00 97.31 21 21 84.23 75.88 

12 3 4 4 1.00 97.76 48 48 85.63 78.28 

13 1 1 2 2.00 97.98 26 26 86.40 79.58 

15 1 2 2 1.00 98.20 30 30 87.28 81.08 

17 2 2 5 2.50 98.77 105 85 90.35 85.34 

20 2 3 4 1.33 99.21 80 80 92.70 89.34 

21 2 2 2 1.00 99.44 78 42 94.99 91.44 

25 1 1 1 1.00 99.55 25 25 95.72 92.69 

35 2 2 2 1.00 99.78 70 70 97.77 96.20 

36 1 1 1 1.00 99.89 36 36 98.83 98.00 

40 1 1 1 1.00 100.00 40 40 100.00 100.00 

------ ------ ------ ------ 

Totals 682 891 3411 1998 

Expected Harvest Reductions Associated with Particular Bag Limits 

Number of Intercepts per Iteration 300 

Number of Iterations 500 

BAG LIMITS 

2 4 6 8 10 12 14 16 18 20 

--- --- --- --- --- --- --- --- --- --- 

Mean 56 34 23 16 12 9 7 6 4 3 

Std Dev 3.4 4.1 4.4 4.4 4.2 3.8 3.4 3.0 2.7 2.2 

Min 47 24 12 7 3 2 1 0 0 0 

Max 64 45 34 28 24 21 18 15 13 10 

28

Table 14. Bag-limit analysis for white grunt using MRFSS interview data for anglers keeping white grunt 

during their fishing trips in Florida Gulf coast waters. The simulation used data for the period 1993-1998 

and even numbered bag-limits from 2 to 20 fish. 

FISH AND WILDLIFE CONSERVATION COMMISSION 

FLORIDA MARINE RESEARCH INSTITUTE 

FISHERIES STATISTICS SECTION 

BAG LIMIT ANALYSIS 

SPECIES : WHITE GRUNT MRFSS DATA : 1993 - 1998 ONLY 

COAST : Gulf 

DATA SOURCE : NMFS Marine Recreational Fisheries Statistical Survey 

********** BASED ON FISH KEPT *********** 

__________________________________________________________________________________________________________________________________ 

Cumulative 

Cumulative 

Number of Fish Number of Number of Number of Average Number of Percentage Number of Fish Percentages of 

Fish 

Kept per Angler Years Trips Anglers Anglers per Trip of Anglers Caught Retained Caught 

Retained 

__________________________________________________________________________________________________________________________________ 

0 6 2265 2651 1.17 45.25 11071 65 35.43 0.39 

1 6 414 844 2.04 59.65 1327 764 39.68 4.92 

2 6 257 508 1.98 68.32 1440 996 44.29 10.83 

3 6 187 398 2.13 75.12 1475 1183 49.01 17.85 

4 6 140 301 2.15 80.25 1492 1162 53.78 24.74 

5 6 121 233 1.93 84.23 1498 1155 58.58 31.60 

6 6 102 152 1.49 86.82 1112 904 62.14 36.96 

7 6 55 112 2.04 88.74 892 763 64.99 41.49 

8 6 66 131 1.98 90.97 1273 1027 69.06 47.58 

9 6 17 43 2.53 91.71 469 378 70.57 49.82 

10 6 73 120 1.64 93.75 1408 1198 75.07 56.93 

11 4 8 12 1.50 93.96 139 130 75.52 57.70 

12 6 38 51 1.34 94.83 703 609 77.77 61.32 

13 6 29 64 2.21 95.92 872 823 80.56 66.20 

14 5 11 17 1.55 96.21 250 236 81.36 67.60 

15 6 32 41 1.28 96.91 715 613 83.65 71.24 

16 2 6 10 1.67 97.08 175 160 84.21 72.19 

17 4 6 16 2.67 97.35 272 270 85.08 73.79 

18 5 9 15 1.67 97.61 313 267 86.08 75.38 

19 4 6 10 1.67 97.78 210 187 86.75 76.48 

20 6 24 39 1.63 98.45 805 780 89.33 81.11 

22 3 3 5 1.67 98.53 143 110 89.78 81.77 

23 3 4 11 2.75 98.72 271 251 90.65 83.26 

24 2 5 5 1.00 98.81 120 120 91.04 83.97 

25 5 8 12 1.50 99.01 325 300 92.08 85.75 

26 1 1 2 2.00 99.04 51 51 92.24 86.05 

27 2 2 5 2.50 99.13 136 133 92.67 86.84 

28 1 2 3 1.50 99.18 103 83 93.00 87.33 

29 1 1 1 1.00 99.20 29 29 93.10 87.50 

30 5 10 14 1.40 99.44 422 422 94.45 90.01 

33 1 1 3 3.00 99.49 100 100 94.77 90.60 

34 1 1 2 2.00 99.52 67 67 94.98 91.00 

35 3 3 3 1.00 99.57 120 105 95.37 91.62 

40 5 11 11 1.00 99.76 455 440 96.82 94.23 

47 1 1 4 4.00 99.83 202 187 97.47 95.34 

50 3 3 4 1.33 99.90 200 200 98.11 96.53 

60 1 1 1 1.00 99.91 63 60 98.31 96.88 

75 1 1 1 1.00 99.93 75 75 98.55 97.33 

100 1 1 3 3.00 99.98 303 300 99.52 99.11 

150 1 1 1 1.00 100.00 150 150 100.00 100.00 

------ ------ ------ ------ 

Totals 3926 5859 31246 16853 

Expected Harvest Reductions Associated with Particular Bag Limits 

Number of Intercepts per Iteration 300 

Number of Iterations 500 

BAG LIMITS 

2 4 6 8 10 12 14 16 18 20 

--- --- --- --- --- --- --- --- --- --- 

Mean 66 46 33 25 19 15 12 10 8 6 

Std Dev 4.1 5.9 6.4 6.3 6.2 5.9 5.6 5.3 5.0 4.6 

Min 54 31 19 11 5 2 1 1 0 0 

Max 75 61 52 45 39 34 31 28 25 23

5.5 

5.0 

West Coast of Florida (Murie and Parkyn 1998) 

Carolinas (Potts and Manooch In review) 

Southeastern Florida (Potts and Manooch In review) 

4.5 

4.0 

WEIGHT (LB) 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

0.0 

0 2 4 6 8 10 12 14 16 18 20 22 

MAXIMUM TOTAL LENGTH (INCH) 

Figure 1. Weight as a function of total length for white grunt from 

the west coast of Florida, southeastern Florida, and the Carolinas.

2 

100 

PERCENT FREQUENCY 

80 

60 

40 

20 

FEMALES (n=589) 

MALES (n=714) 

0 

0 5 10 15 


Figure 2. Percent frequency of mature female and male white grunt from the 

west coast of Florida (modified from Murie and Parkyn 1999).

3 

100 

DEVELOPING 

VITELLOGENIC 

HYDRATED 

SPENT, RESTING 

90 

80 

70 

PERCENT 

60 

50 

40 

30 

20 

10 

0 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

MONTH OF THE YEAR 

Figure 3. Percent frequency of mature female white grunt as a function 

of gonad stage and month of collection (from Murie and Parkyn 1999).

5 

10 

A) FEMALES n=560 

8 

6 

GSI 

4 

2 

3 

0 


B) MALES n=659 

GSI 

2 

1 

0 


MONTH 

Figure 4. Mean monthly GSI values (± 1SE) for (A) mature female white grunt and 

(B) mature male white grunt (from Murie and Parkyn 1999).

6 

100 

SPERMATOGENIC 

RIPE 

SPENT, RESTING 

RECOVERING, MATURING 

90 

80 

70 

PERCENT 

60 

50 

40 

30 

20 

10 

0 

JAN FEB MAR APR MAY JUN 

JUL AUG SEP OCT NOV DEC 

MONTH OF THE YEAR 

Figure 5. Percent frequency of mature male white grunt as a function 

of gonad stage and month of collection (from Murie and Parkyn 1999).

7 

0.8 

INDEX OF COMPLETION 

0.6 

0.4 

0.2 

n=368 

0.0 


Figure 6. Index of completion of the marginal increment as a function of month of the year 

for white grunt from the west coast of Florida (from Murie and Parkyn 1999).

8 

20 

MAXIMUM TOTAL LENGTH (INCHES) 

15 

10 

5 

FEMALE: TRAP (n=326) 

MALES: TRAP (n=375) 

FEMALES: RESEARCH (n=208) 

MALES: RESEARCH (n=276) 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

AGE (YR) 

Figure 7. von Bertalanffy growth curves for male and female white grunt collected in research sampling and from the 

commercial trap fishery in the eastern Gulf of Mexico (modified from Murie and Parkyn 1999).

9 

TOTAL LENGTH (INCHES) 

20 

15 

10 

5 

0 

West Coast Florida (Murie and Parkyn 1999) 

Southeastern Florida (Potts and Manooch In review) 

South Atlantic Bight: MARMAP (Padgett 1997) 

South Atlantic Bight: Commercial (Padgett 1997) 

Carolinas (Manooch 1976) 

Carolinas (Potts and Manooch In review) 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 

AGE (YR) 

Figure 8. Von Bertalanffy growth curves for white grunt collected in the west coast of 

Florida (Murie and Parkyn 1999), southeastern Florida (Potts and Manooch In review), 

the Carolinas (Manooch 1976), and the South Atlantic Bight (Padgett 1997). 

Total lengths were converted from mm to inches for all studies.

600 

600 

Estimated Atlantic Landings (lbs) 

Estimated Atlantic Landings (nos.) 

500 

400 

300 

200 

100 

0 

1000 

800 

600 

400 

200 

0 

Gulf 

Atlantic 

86 88 90 92 94 96 98 

Year 

Gulf 

Atlantic 

86 88 90 92 94 96 98 

Year 

Figure 9. Estimated annual commercial landings of white grunts in both pounds (top) and numbers (bottom). 

Estimates were based on reported landings of 'grunts', a region-specific species composition breakdown 

based on TIP sampling, and the average weights of measured white grunt in the TIP. 

500 

400 

300 

200 

100 

0 

600 

500 

400 

300 

200 

100 

0 

Estimated Gulf Landings (lbs) 

(Thousands) 

Estimated Gulf Landings (nos.) 

(Thousands)

Gulf, 1992 

Gulf, 1996 

Frequency 

200 

150 

100 

50 

0 

5 10 15 20 25 30 

Fork Length (inches) 

Frequency 

160 

140 

120 

100 

80 

60 

40 

20 

0 

5 10 15 20 25 30 


Gulf, 1993 

Gulf, 1997 

250 

100 

200 

80 

Frequency 

150 

100 

50 

Frequency 

60 

40 

20 

0 

5 10 15 20 25 30 


0 

5 10 15 20 25 30 


Gulf, 1994 

Gulf, 1998 

80 

600 

Frequency 

60 

40 

20 

Frequency 

500 

400 

300 

200 

100 

0 

5 10 15 20 25 30 


0 

5 10 15 20 25 30 


Gulf, 1995 

Gulf, 1999 

10 

50 

8 

40 

Frequency 

6 

4 

2 

Frequency 

30 

20 

10 

0 

5 10 15 20 25 30 


0 

5 10 15 20 25 30 


Figure 10. Lengths of commercially caught white grunt landed on the Gulf coast during 1992-1999.

4 

3 

Frequency 

2 

1 

0 

0 0.5 1 1.5 2 2.5 3 

Weight (lbs) 

1997 1998 

300 

250 

Frequency 

200 

150 

100 

50 

0 

0 0.5 1 1.5 2 2.5 3 

Weight (lbs) 

1997 1998 

Figure 11. Whole weights (lbs) predicted from white grunts lengths measured by TIP samplers during 

1997 and 1998 on the Atlantic (top) and Gulf (bottom) coasts of Florida.

1,000 

Estimated Number of Fish 

(Thousands) 

800 

600 

400 

200 

Released Alive 

Landed 

0 

8 

82 84 86 88 90 92 94 96 98 

Year 

Estimated Number of Fish 

(Millions) 

6 

4 

2 

Released Alive 

Landed 

0 

82 84 86 88 90 92 94 96 98 

Year 

Figure 12. Estimated numbers of white grunt landed and numbers released alive 

by anglers on the Atlantic (top) and Gulf (bottom) coasts of Florida each 

year during 1982-98.

Estimated Number of Trips 

(Thousands) 

1400 

1200 

1000 

800 

600 

400 

200 

Glf 

Atl 

0 

86 88 90 92 94 96 98 

Year 

Figure 13. Estimated annual number of fishing trips made in private or rental boats by 

anglers who caught or were trying to catch white grunt.

Proportion of Annual Landings 

0.6 

0.4 

0.2 

0 

Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec 

Time Period 

Proportion of Annual Landings 

0.6 

0.4 

0.2 

0 

Jan-Feb Mar-Apr May-Jun Jul-Aug Sep-Oct Nov-Dec 

Time Period 

Figure 14 . Bimonthly distribution of white grunt landings by anglers during 1986-98. The 95% confidence 

interval (vertical lines), interquartile range (box) and median (filled circle) are presented for the distribution of 

a wave's landings relative to that year's annual landings.

a. Atlantic 

25 

20 

Landings 

(Thousands) 

15 

10 

5 

0 

Number 

198919901991199219931994199519961997 

Year 

Pounds 

b. Gulf 

1,000 

800 

Landings 

(Thousands) 

600 

400 

200 

0 

Number 

1989 1991 1993 1995 1997 

Year 

Pounds 

Figure 15. Headboat landings of white grunt by coast in numbers (bar) and 

pounds (line).

A) SPAWNING FEMALES (N=465) 

B) SPAWNING MALES (N=556) 

50 

50 

PERCENT 

40 

30 

20 

10 

40 

30 

20 

10 

0 

5 6 7 8 9 10 11 12 13 14 15 

0 

5 6 7 8 9 10 11 12 13 14 15 

C) POST-SPAWN FEMALES (N=536) 

D) POST-SPAWN MALES (N=573) 

50 

50 

PERCENT 

40 

30 

20 

10 

40 

30 

20 

10 

0 

5 6 7 8 9 10 11 12 13 14 15 

0 

5 6 7 8 9 10 11 12 13 14 15 


Figure 16. Length frequencies of female and male white grunt sampled from the 

head-boat fishery on the west coast of Florida during and after the spawning season.

2 

A) SPAWNING FEMALES (N=436) 

B) SPAWNING MALES (N=530) 

PERCENT 

40 

30 

20 

10 

40 

30 

20 

10 

0 

0 2 4 6 8 10 12 14 16 18 

0 

0 2 4 6 8 10 12 14 16 18 

C) POST-SPAWN FEMALES (N=532) 

D) POST-SPAWN MALES (N=572) 

PERCENT 

40 

30 

20 

10 

0 

40 

30 

20 

10 

0 

0 2 4 6 8 10 12 14 16 18 0 2 4 6 8 10 12 14 16 18 

AGE CLASS 

Figure 17. Frequencies of age classes of female and male white grunt sampled from the 

head-boat fishery on the west coast of Florida during and after the spawning season.

600 

Numbers of fish landed 

(Thousands) 

500 

400 

300 

200 

100 

0 

89 90 91 92 93 94 95 96 97 98 

Year 

Recreational A+B1 Reported Commercial Estimated headboat 

350 

300 

Pounds Landed 

(Thousands) 

250 

200 

150 

100 

50 

0 

89 90 91 92 93 94 95 96 97 98 

Year 


Figure 18. Total annual landings of white grunt on the Atlantic coast of Florida. Note that 

the estimate of headboat landing was not available for 1998.

Numbers of fish landed 

(Millions) 

4 

3 

2 

1 

0 

89 90 91 92 93 94 95 96 97 98 

Year 


3 

Pounds Landed 

(Millions) 

2 

1 

0 

89 90 91 92 93 94 95 96 97 98 

Year 


Figure 19. Total annual landings of white grunt on the Gulf coast of Florida. Note that 

the estimate of headboat landing was not available for 1998.

1.2 

Average Weight (lbs) 

1 

0.8 

0.6 

0.4 

82 84 86 88 90 92 94 96 98 

Year 

Recreational Commercial Headboat 

1.2 

Average Weight (lbs) 

0.9 

0.6 

0.3 

0 

82 84 86 88 90 92 94 96 98 

Year 

Recreational Commercial Headboat 

Figure 20. Average weights of white grunts sampled for the non-head-boat recreational fishery, 

the commercial fishery, and the head-boat fishery on the Atlantic (top) and Gulf (bottom) 

coasts of Florida during 1982-1998.

10 

Standardized Catch per Trip 

8 

6 

4 

2 

29 

35 

35 

19 

32 

38 

4 

6 

46 

97 

182 

108 

105 

66 

86 

58 126 

0 

82 84 86 88 90 92 94 96 98 

Year 

8 

Standardized Catch per Trip 

7 

6 

5 

4 

3 

104 

39 

47 

25 

45 

149 

192 

179 

162 310 

475 

583 564 

488 

485 469 594 

2 

82 84 86 88 90 92 94 96 98 

Year 

Figure 21. Annual standardized total catch per trip for boat anglers targeting or catching 

white grunt on the Atlantic (top) or Gulf (bottom) coasts of Florida during 1982-1998. 

Vertical lines indicate 95% confidence intervals, boxes are 50% intervals, and filled 

circles are median estimates. Numbers are the number of trip interviews made.

a. Atlantic 

Number of fish 

2,000,000 

1,800,000 

1,600,000 

1,400,000 

1,200,000 

1,000,000 

800,000 

600,000 

400,000 

200,000 

0 

86 87 88 89 90 91 92 93 94 95 96 97 98 

Year 

b. Gulf 


18,000,000 

16,000,000 

14,000,000 

12,000,000 

10,000,000 

8,000,000 

6,000,000 

4,000,000 

2,000,000 

0 

86 87 88 89 90 91 92 93 94 95 96 97 98 

Year 

Figure 22. Estimated annual average number of white grunt on the Atlantic coast (top) and Gulf coast 

(bottom) as predicted from the two modified DeLury models used for each coast.

Biomass / biomass at MSY 

3.5 

3 

2.5 

2 

1.5 

1 

0.5 

Gulf 

Atlantic 

0 

86 88 90 92 94 96 98 

Year 

Figure 23. Estimated annual average biomass of the white grunt populations on the Atlantic and Gulf coasts of Florida 

during 1986-1998.

0.5 

1 

0.4 

Atl-ASPIC 

0.8 

F per year 

0.3 

0.2 

Atl-Del1 

Atl-Del2 

0.6 

0.4 

F / Fmsy 

0.1 

0.2 

0 

0 

86 88 90 92 94 96 98 

Year 

0.35 

1 

0.3 

Glf-ASPIC 

0.8 

F per year 

0.25 

0.2 

Glf-Del1 

Glf-Del2 

0.6 

0.4 

F / Fmsy 

0.15 

0.2 

0.1 

0 

86 88 90 92 94 96 98 

Year 

Figure 24. Estimates of instantaneous fishing mortality rates for white grunt on the Atlantic (top) and Gulf 

(bottom) coasts of Florida during 1986-1998. Absolute estimates were made using two formulations of the 

modified DeLury model (Del1, Del2). Estimates from the ASPIC biomass dynamic model are reported 

relative to the estimated Fmsy value (see text).

0.15 

Standardized Catch per Set 

0.1 

0.05 

0 

-0.05 

-0.1 

89 90 91 92 93 94 95 96 97 98 

Year 

Figure 25. Standardized annual catch per set for white grunt young-of-the-year (0-100 mm SL) 

captured by the the Fishery-Independent monitoring program in Tampa Bay and Charlotte 

Harbor. Only the 1996 estimate is significantly different from zero.

a. Atlantic 

Numbers of fish 

900,000 

800,000 

700,000 

600,000 

500,000 

400,000 

300,000 

200,000 

100,000 

0 

87 88 89 90 91 92 93 94 95 96 97 98 

b. Gulf 

Year 


10,000,000 

9,000,000 

8,000,000 

7,000,000 

6,000,000 

5,000,000 

4,000,000 

3,000,000 

2,000,000 

1,000,000 

0 

87 88 89 90 91 92 93 94 95 96 97 98 

Year 

Figure 26. Estimated annual average number of fish recruiting to the white grunt populations on the Atlantic 

coast (top) and Gulf coast (bottom) as predicted from the two modified DeLury models used for each coast.

Yield per recruit (lbs) 

0.25 

0.2 

0.15 

0.1 

0.05 

0 

Gulf 

F0.1 

F35% 

Atlantic 

F20% 

Fmax 

0.0 0.2 0.4 0.6 0.8 1.0 

Fishing mortality rate (F) 

Figure 27. Yield-per-recruit and spawning potential ratio relationships for female white grunt. Estimates use life history 

characteristics for white grunt from the Gulf coast of Florida. Current estimates of F are shown by thickened line 

under the x-axis. 

1.0 

0.8 

0.6 

0.4 

0.2 

0.0 

Spawning potential ratio (-----)

STOCK ASSESSMENT OF WHITE GRUNT FROM THE WEST ...

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