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

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were selected. Fish selected for tagging were retained in a perforated holding bucket strapped to theside of the boat (Plate 3). Prior to acoustic tagging, fish were measured (nearest mm, fork length,FL) and tagged with an external T-bar spaghetti-type tag (Floy Tag and Mfg, Inc, Seattle, WA),inserted between the dorsal pterygiophores, to enable fishers to identify acoustically tagged fish intheir catches.Plate 2. Schematicdiagram showing themethod used for rangetestingtransmitters.Plate 3. a) Traditional baskettraps used to captureSiganus sutor; b) perforatedbucket strapped to side ofboat for holding live fish.(See colour plates.)Acoustic transmitters were inserted into the body cavity through through the ventral body wall.Using a surgical scalpel blade, incisions of ~ 2 cm in length were made, positioned slightly abovethe anus and about 2/3 distance below the lateral line. Surgeries were performed following 3 minanaesthesia using 45 mg/l clove oil dissolved in seawater, a concentration based on prior tests (seeAppendix II). For surgery, anaesthetised fish were placed upside down in a canvas cradle suspendedin an aerated aquarium cushioned with soft sponge on the walls (Plate 4). After tag insertion, theincision was sutured with two nylon-polyamide sutures and the fish was transferred to the holdingbucket until normal movement had resumed. Untagged fish were retained and released in groupswith tagged fish to help them orientate. Fish were released near acoustic receivers and observed onsnorkel. All tagged fish swam rapidly to the bottom and disappeared into holes in the reef. To aidin tag recovery, an awareness-raising programme involving seminars and distribution of a tag returnform was conducted in collaboration with a local conservation group in Msambweni.Data AnalysisResidency time at a spawning aggregation site was defined as the time (hr) between the first acousticdetection and the last detection within a 24-hr period. If the fish was not detected for >24 hr itwas assumed to have left the site or died. Continuous detections in 24-hr periods were summed togive total residency.36
All data were assigned a lunar phase following Samoilys (1997b) where the lunar cycle starts withthe new moon (NM) on lunar day (LD) 1: NM = LD 28-3; First Quarter (FQ) = LD 6-10; fullmoon (FM) = LD 14-18; Last Quarter (LQ) = LD 21-25.Plate 4. a) S. sutoranaesthetised with cloveoil in 10 litres of aeratedseawater; b) surgical incisionprior to V7-2L taginsertion and suturing.ResultsVerification of spawning aggregation formation, sites and targeted fishingUVC surveys provided evidence that S. sutor aggregations formed at the three sites, although astrong time-series of data was not obtained. Highest abundances at all three sites were observedin December and February (Fig. 2), with the largest aggregations occurring at Site B. At Site A,aggregations were only observed during December and no aggregations were observed in Januaryat any of the sites. Maximum numbers were recorded on LD 14,17 and 18 (~ full moon) at Sites Band C, and ranged from 62-257. Minimum numbers were in November and ranged from 0-8 fish(Fig. 2). Differences between minimum and maximum numbers at Sites B and C provide evidenceof aggregation formation.S. sutor school for purposes other than reproduction, making verification of aggregation forspawning imperative. Of the four behaviours typically used as indicators of reproductive activity(i.e. courtship, colour change, spawning rushes and gamete release) only changes in colourationwere observed. The change was represented by a white and a black line appearing mid-laterally.At the sites, S. sutor swam at high speed close to the bottom in small groups of typically 2-15 fishand up to 25 fish per group. Individuals observed changing colour represented 6-23% of the fishin these schools. The schools swam in all directions and the majority (42% of fish) were recordedcircling. Detailed behavioural patterns were hard to discern because the fish swam in and out ofthe diver’s field of view.Fig. 2. Total numbers of S. sutor on Sites A, B and C during November 2009 to March 2010. Lunar day: 1= newmoon, 15-16 = full moon.37
Page 4: The designation of geographical ent
Page 9: Chapter 1: IntroductionJan Robinson
Page 12 and 13: limited, subsistence levels of expl
Page 14: NTRs for spawning aggregations usin
Page 17 and 18: al. 2003). Verification may include
Page 19 and 20: a fraction of spawning sites are pr
Page 21 and 22: Chapter 3: Targeted fishing of the
Page 23 and 24: verifying spawning aggregations, we
Page 25 and 26: ecorded from inshore close to the c
Page 27 and 28: (a)(b)Fig. 3. Spatial patterns ofca
Page 30 and 31: pooled sizes of the three spawning
Page 32 and 33: found S. sutor contributed up to 44
Page 34 and 35: 2011b). However, observations of fi
Page 36 and 37: MethodsTo identify seasonal and lun
Page 38 and 39: n=199Females GSI (mean ± SE)2.521.
Page 40 and 41: The estimate of size at maturity in
Page 42 and 43: This study was designed to verify S
Page 46 and 47: The number of traps increased on th
Page 48 and 49: 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
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Fig. 2. Mean (± standard error, SE
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A few species (e.g. Epinephelus gut
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(a)(b)Fig. 1. Map of (a) study site
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Fig. 2. Number of E. lanceolatus ob
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was having any impact on the popula
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A spawning aggregation is said to o
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Chapter 11: Evaluation of an indica
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Table 1 Aggregation fisheries asses
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the lists of Jennings et al. (1999)
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with the more vulnerable labrids an
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The remaining serranid populations
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Spawning aggregation behaviour is c
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tiger grouper, Mycteroperca tigris:
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of protecting the normal residence
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• Since grouper males are afforde
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Fig. 2 Yield-per-recruit normalized
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The approaches identified above are
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during full moon periods. Siganus s
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model, many parameter estimates are
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ReferencesAbunge C (2011) Managing
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Cox DR (1972) Regression models and
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Grüss A, Kaplan DM, Hart DR (2011b
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Kaunda-Arara B, Rose GA (2004a) Eff
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Newcomer RT, Taylor DH, Guttman SI
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Sancho G, Petersen CW, Lobel PS (20
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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
Page 161 and 162:
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