WIOMSA-CORDIO spawning book Full Doc 10 oct 13.pdf

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(a)(b)Fig. 1. Map of (a) study site on the southern end of Unguja Island, Zanzibar and(b) village and reef areas where fishers and fishery were observed.Catch landings dataLandings of E. lanceolatus in Kizimkazi village were recorded on 36 different days between 13November 2009 and 26 February 2010 during which 64 individual E. lanceolatus were sampledfrom 43 catches. Sample records included: vessel type, number of fishers, gear type and size, fishinglocation, fish total length and body depth (to 0.1 m), and gonad colour and weight (to 0.5 kg).Sampled fish were too large to be weighed at the landing site and therefore total fish weightwas estimated approximately from fish lengths, based on a single 170 kg fish that was weighedin Zanzibar town. For reasons not clear, fishers were reluctant to sell us E. lanceolatus gonads,therefore, no samples were available for histological or macroscopic analysis. Instead gonads wereonly weighed and described by colour (red or white). Sampling effort was not stratified evenlyacross months or lunar phases, therefore, statistical differences should be interpreted with caution.Fisher knowledgeQuestionnaires (modified from the questionnaires used in Kenya, see Chapter 3) were used tointerview 17 fishers in Kizimkazi to gain knowledge of their fishing patterns in relation to E.lanceolatus and their knowledge of spawning aggregations, including their occurrence, location,and timing. These fishers were selected based on information collected during an earlier studythat identified them as the only fishers out of 150 fishers in Kizimkazi targeting E. lanceolatus. Inaddition, a focus group discussion (FGD) was held in February 2010 with 8 of the 17 fishers tofurther discuss their knowledge of the E. lanceolatus fishery and to cross check answers from priorinterviews.SCUBA observationsTwo SCUBA dives were carried out on the full moon of February 2010 on the offshore reef fishingsite where fishers reported catching E. lanceolatus. The dives were done to observe E. lanceolatus, tosee if they were aggregating and whether they were exhibiting any recognisable spawning-relatedbehaviour (Colin et al. 2003). The purpose of the dives was also to describe the reef topography ofthe presumed spawning site. Only two dives were done because the conditions were too dangerouswith bottom depths in excess of 40 m and very strong currents.94
Data AnalysisData were assigned a lunar phase (LD) following Samoilys (1997b), where the lunar cycle startswith the new moon (NM, LD 1): NM = LD 28-3; first quarter (FQ) = LD 6-10; full moon (FM)= LD 14-18; last quarter (LQ) = LD 21-25. Samples from days in between these 4 phases (n=15)were not used in lunar comparisons.A one-way ANOVA was used to compare GSI between months. February was excluded due to lowsample size. Due to unequal monthly samples sizes, we selected the Scheffe post-hoc comparisonfollowing identification of significant differences between monthly GSI (Ruxton and Beauchamp2008).ResultsFishers interviewed at the Kizimkazi village landing site in July 2010 reported seasonal targeting ofE. lanceolatus at an offshore reef located off the southern end of Unguja Island, the main island ofZanzibar. Fishers accessed the reef site using 4 fibreglass boats based in Kizimkazi, with an averageof 4 crew using hook-and-line gear, set and hauled by hand.Fig. 1. Total number ofEpinephelus lanceolatus observedin landed catches at Kizimkaziby survey month.Of the 17 fishers interviewed, 9 reported targeting E. lanceolatus from November to February,while 7 fishers reported October to February. These dates were confirmed in the FGD where fishersreported November to January or February. Surveys of landed catch at Kizimkazi between 13November 2009 and 26 February 2010 confirmed that E. lanceolatus regularly appears in the catchduring November – February, with the highest catches recorded in January (Fig. 1). A total of 64E. lanceolatus were observed in landings during the 15 weeks of landings surveys, giving an averageof more than 4 fish landed per week. Fish ranged in total length from 101 - 235 cm TL (mean 1.92+ 0.33 cm SD, standard deviation). While landings surveys were not formally conducted in othermonths, fisheries data reports (Institute of Marine Studies (IMS), unpubl. data) indicated that thisspecies was absent or rare in landed catches during other periods or locations.A lunar pattern was apparent in the landings, with the highest catches corresponding to the fullmoon and the first quarter, although E. lanceolatus were caught throughout the lunar month (Fig.2). All but one of the 17 fishers interviewed reported that they catch E. lanceolatus around the fullmoon. This was not supported by the FGD where fishers reported new moon and last quarter (LD21 to 4) as the period in which they catch the most E. lanceolatus.Gonads weighed between 1.0 and 9.0 kg with a mean of 4.9 kg (+ 2.1 SD). There were significantdifferences in mean GSI between months (F = 5.88; P = 0.02) (Fig. 3). Post-hoc comparisonsindicate that GSI in November was greater than both December (P = 0.019) and January (P =0.032), while other comparisons were insignificant. There were no significant differences in GSIbetween lunar phases (F < 1; P = 0.70) (Fig. 3).95
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The designation of geographical ent
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Chapter 1: IntroductionJan Robinson
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limited, subsistence levels of expl
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NTRs for spawning aggregations usin
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al. 2003). Verification may include
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a fraction of spawning sites are pr
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Chapter 3: Targeted fishing of the
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verifying spawning aggregations, we
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ecorded from inshore close to the c
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(a)(b)Fig. 3. Spatial patterns ofca
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pooled sizes of the three spawning
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found S. sutor contributed up to 44
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2011b). However, observations of fi
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MethodsTo identify seasonal and lun
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n=199Females GSI (mean ± SE)2.521.
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The estimate of size at maturity in
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This study was designed to verify S
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were selected. Fish selected for ta
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The number of traps increased on th
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Of the 9 tagged fish detected by re
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Fig. 7. Diel patterns ofdetection f
Page 52 and 53: Spawning aggregation site fidelity
Page 54 and 55: Chapter 6: Shoemaker spinefoot rabb
Page 56 and 57: anterior of the anus and below the
Page 58 and 59: A high percentage (80.8%) of depart
Page 60 and 61: arrivals and departures at these tw
Page 62 and 63: are typically applied for reef fish
Page 64 and 65: (a)(b)(c)Chapter 3, Figure 3. Spati
Page 66 and 67: (1)(2)(3)(4)(5)(6)Chapter 7, Table
Page 68 and 69: Chapter 12, Fig. 1 Fraction of fema
Page 70 and 71: Plates 8. Selected photographs from
Page 72 and 73: MethodsStudy sitesThe study area wa
Page 74 and 75: which shelved gently ( ca. 25 o ) t
Page 76 and 77: Fig. 4. Lunar periodicity in number
Page 78 and 79: Behaviour and appearanceDescription
Page 80 and 81: eported aggregations forming betwee
Page 82 and 83: The sizes of E. fuscoguttatus aggre
Page 84 and 85: Materials and methodsStudy area and
Page 86 and 87: TL. All fish tagged were considered
Page 88 and 89: Lunar timing of arrivals and depart
Page 90 and 91: Fig. 8. The presence and absence of
Page 92 and 93: aggregation fishing. This critical
Page 94 and 95: Chapter 9: Persistence of grouper (
Page 96 and 97: ResultsBetween 2003 and 2006, the c
Page 98 and 99: Fig. 2. Mean (± standard error, SE
Page 100 and 101: A few species (e.g. Epinephelus gut
Page 104 and 105: Fig. 2. Number of E. lanceolatus ob
Page 106 and 107: was having any impact on the popula
Page 108 and 109: A spawning aggregation is said to o
Page 110 and 111: Chapter 11: Evaluation of an indica
Page 112 and 113: Table 1 Aggregation fisheries asses
Page 114 and 115: the lists of Jennings et al. (1999)
Page 116 and 117: with the more vulnerable labrids an
Page 118 and 119: The remaining serranid populations
Page 120 and 121: Spawning aggregation behaviour is c
Page 122 and 123: tiger grouper, Mycteroperca tigris:
Page 124 and 125: of protecting the normal residence
Page 126 and 127: • Since grouper males are afforde
Page 128 and 129: Fig. 2 Yield-per-recruit normalized
Page 130 and 131: The approaches identified above are
Page 132 and 133: during full moon periods. Siganus s
Page 134 and 135: model, many parameter estimates are
Page 136 and 137: ReferencesAbunge C (2011) Managing
Page 138 and 139: Cox DR (1972) Regression models and
Page 140 and 141: Grüss A, Kaplan DM, Hart DR (2011b
Page 142 and 143: Kaunda-Arara B, Rose GA (2004a) Eff
Page 144: Newcomer RT, Taylor DH, Guttman SI
Page 147 and 148: Sancho G, Petersen CW, Lobel PS (20
Page 149 and 150: Appendix 1. QuestionnaireMASMA SPAW
Page 151 and 152: 8. Spawning aggregation knowledgeUs
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Example items KSh Furthest site Clo
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Appendix II. Experimental testing o
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Clove oil concentrationAt a concent
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Appendix III. Application of acoust
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