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

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A few species (e.g. Epinephelus guttatus) appear to form aggregations that vary naturally betweenyears in terms of their distribution and density (Shapiro et al. 1993; Sadovy et al. 1994b). Ourresults indicate that the location and distribution of aggregations that are more localised, denser anddiscrete (Colin 1992; Eklund et al. 2000) may also change on longer time scales, which will requireconsideration in management design. If pre-cyclone area management had been applied only tocore spawning areas A and B, the post-cyclone changes to distribution would have predisposed theaggregations to fishing. Thus, variability in aggregation distribution provides a strong argument forlarger protected areas, or at least buffer areas (Nemeth 2012).Such mechanisms identify the need for adaptive management in the use of spatial closures toprotect spawning aggregations. At our study sites, fragmentation of the preferred spawning habitatresults in the E. fuscoguttatus and E. polyphekadion aggregation cores splitting into relatively discreteunits roughly defined by the boundaries of hard substrate (Fig. 1). In the absence of any furtherlarge-scale habitat modification, aggregation distribution may remain stable for these species atpopulation carrying capacity. However, the application of spatial protection measures for manyspawning aggregations will need to be adaptive, since protection is most often applied whenpopulations are depleted. Following protection, subsequent recovery may lead to further changesin the distribution of aggregations, as the increased numbers of fish seek additional fragments ofhabitat. If the new distribution extends beyond boundaries, any benefits provided for by small,protected areas will be undermined.The natural experiment afforded our study showed that the traditional use of spawning sites wasmaintained through habitat change. The fact that aggregating fish can adjust to a partial loss ofspawning habitat reinforces the argument that the main threat to spawning aggregation persistenceis fishing.92
Chapter 10: A niche fishery targeting the Giant grouper(Epinephelus lanceolatus) in ZanzibarMelita Samoilys, Narriman Jiddawi and Jan RobinsonIntroductionThe brindle bass, or Giant grouper, Epinephelus lanceolatus (Epinephelidae, Bloch 1790) is thelargest bony fish and the most widely distributed grouper in the world (Gomon et al. 1994;Heemstra and Randall 1993; Smith and Heemstra 2003; Craig and Hastings 2007). Records givea maximum weight of 400 kg, a maximum size of around 300 cm total length and male size at firstmaturity of approximately 129 cm (Heemstra and Randall 1993; Lau and Li 2000). It occurs fromthe Red Sea to Algoa Bay, South Africa, and eastward to the Hawaiian and Pitcairn islands, northto southern Japan and south to Australia. Little is know about its biology. The species appears tobe rare across its range and is rarely reported in fisheries landings (Heemstra and Randall 1993,Pogonoski et al 2002; Daw 2004). It is a target of spearfishers and has naturally low populationabundance though growth rates may be quite high (Myers 1991; IUCN 2011). Giant grouper isclassified as Vulnerable on the IUCN Red List due to population declines attributed to extensivefishing pressure and species desirability in the Hong Kong live reef fish market combined with itsnatural low abundance (IUCN 2011, Sadovy de Mitcheson et al. 2012). Sattar and Adam (2005)listed this species as a commonly exported species in Maldives, particularly to Hong Kong.Earlier investigations by the authors in 2005-2007 indicated that E. lanceolatus becomes temporarilyimportant in catches in one location of Unguja Island in Zanzibar during certain months of the yearand catch numbers were indicative of aggregation fishing (Jiddawi and Samoilys unpub.; Samoilyset al. 2006). This and other Red Listed species in general, are not specifically managed in ZanzibarFisheries legislation (Zanzibar Fisheries Act 2010). Our study was designed to document thisfishery and address the question: are fishers targeting a spawning aggregation(s) of the vulnerableGiant grouper in Zanzibar and what are the future research needs for the species and site(s)?Many species of grouper aggregate to spawn at specific sites and times each year, which has madethem highly vulnerable to fishing and over-exploitation (Domeier and Colin 1997; Sadovy andDomeier 2005; Sadovy de Mitcheson and Erisman 2012). Unusually elevated catches such asthose reported for E. lanceolatus in Zanzibar are often indicative of aggregation formation andtargeted aggregation fishing. No scientific research has been done on the spawning behaviour ofE. lanceolatus and its demographics are poorly known, with only anecdotal reports from fishersavailable (Domeier et al. 2002). Interviews with fishermen in eastern Indonesia provided indirectevidence of spawning aggregations where seasonally, catches increased from an average of 1 to6 fish/week/boat during the possible aggregation season. Multiple gravid females were observedduring periods of high catch (Sadovy and Liu 2004).The study is limited by the rarity of the species and its conservation status. Therefore, no extractivesamples were taken for this research. The study was dependent on collaboration with fishers andin-water surveys to identify the potential aggregation site of this species in the Kizimkazi area whereelevated catches had been reported.MethodsStudy siteThe study was located at Kizimkazi which has two sub-villages, Mkunguni and Dimbani, on thesouthern end of Unguja Island, Zanzibar (Fig. 1) and an offshore reef to the south east of Kizimkaziwhose location is being kept confidential due to the sensitivity of releasing information on thelocation of spawning aggregations.93
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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
Page 50 and 51: 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 102 and 103: (a)(b)Fig. 1. Map of (a) study site
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
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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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