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

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A high percentage (80.8%) of departures from the spawning sites occurred during the 7-dayreproductive period with the number of departures peaking at 1 and 2 days after the full moon(Fig. 1a). At Polite, peak departures occurred on and 1 day after the full moon with 30.4% ofdepartures recorded on each day (Fig. 2b). As with arrivals, peak departures from Dividi wereslightly later than Polite, occurring 2 (38.9% of departures) after the full moon (Fig. 2c) At Désiré,there were no discernible trends, with departures appearing haphazard (Fig. 2d).Diel timing of arrivals and departuresPooling data across sites, arrival time of fish at the spawning sites peaked in the morning with42.3% of arrivals occurring between 0500 and 0700 (Fig. 3a). This was driven by patterns in peakhourly arrivals at Dividi (Fig. 3b) and Polite (Fig. 3c). The pattern differed at Désiré, with 2 smallpeaks of arrivals, one occurring between 0500 and 0600 and one between 1700 and 1900 (Fig. 2d).Peak period of departure occurred between 1700 and 1900 with 57.7% of all departures occurringwithin this period (Fig 3a). At other times of the day the number of departures remained low, withno hourly period accounting for more than 6% of departures. Most departures at Polite (78.3%)and Dividi (66.7%), occurred from 1700 to 1900 (Fig. 3b, c). At Désiré, there were 3 small peaksof departures, the largest occurring between 1800 and 1900 (27.3% of departures), whereas twosmaller peaks, each accounting for 18.2% of departures, occurred between 0100 and 0200 and0500 and 0600.Residence timeFig. 4. Differences in the residency times of tagged between monitoring period 1 and 2 at all monitored spawningaggregation sites combined and at Polite.Within each period residence time did not differ statistically between the FSA sites, i.e. betweenPolite and Désiré in Period 1, and between Polite and Dividi in Period 2. By contrast, significantdifferences in residence time (Wilcoxon Ranked Sum Test: W = 1170, P < 0.001) were observedfrom pooling data across site in each period and then comparing between periods, with residencetime in Period 1 being on average ca. 4-fold greater than in Period 2 (Fig. 4). While period maybe important for CRT, the difference may be an artefact of pooling data from different pairs ofsites during each tagging periods. However, comparison of residence time between periods 1 and50
2 for Polite, the only site where tagging was performed in both periods, was statistically significant(Wilcoxon Ranked Sum Test: W = 341, P < 0.001; Fig. 5) and provides evidence that period isimportant. There were important differences in residence time between months at Polite (H =22.35, df = 6, P = 0.001; Fig. 5). Post-hoc pair-wise comparisons revealed that the significantdifferences in residence time were present only between October and January and between Octoberand February. There were no significant differences in residence time at Desire and Polite in Period1 and at Dividi and Polite in Period 2.Fig. 5. Inter-monthly variation in residence time at Polite between October 2010 and April 2011. Grey bars are CRTsfor fish that were tagged in Period 1, black bar is for fish that were tagged in both periods, and white bars are for fishthat were tagged in Period 2Spawning site fidelityFish showed high fidelity to spawning sites with 22 of the 35 tagged fish (62.9%) detected onmore than one spawning month (Fig. 6). Fish that were detected on more than one spawningaggregation period exhibited a high but not absolute degree of site fidelity, with 19 of the 22 fish(86.4%) detected at only one monitored FSA site. Ten and 4 tagged fish visited the same FSAsite on 3 and 4 consecutive spawning aggregation periods, respectively, whereas 5 others visitedthe same site twice. Two fish tagged in monitoring period 1 (ID 40182, 40189) and one fish (ID41493) tagged in monitoring period 2 were detected at more than one FSA site (Fig. 6a, b). FishID 40182 was tagged at Polite in October 2010 and was subsequently detected at Dividi (morethan 8 km away) over the next 3 spawning aggregation periods. Fish ID 40189 remained at the siteof tagging (Désiré) for an extensive period (3 months), including 6 consecutive days of the 7-dayspawning aggregation period in the last month (January 2011) of monitoring period 1. Furtherdemonstrating the spatial and temporal scales of mobility, after departing Désiré at dusk on the 6 thday of the spawning aggregation period (i.e. 2 days after the full moon), the same individual wasdetected the next morning at Dividi, where it stayed for 6 h and attended the spawning aggregationat that site with other tagged fish. An individual (Fish ID 41493) tagged at Dividi in January 2011appeared at Désiré the day after tagging, where it stayed for 2.5 days, and returned to Dividi duringthe 2 subsequent spawning aggregation periods of February and March 2011.DiscussionThis study has provided new knowledge on the spawning aggregation dynamics of S. sutor atoffshore spawning aggregation sites in the Seychelles. The findings of this study confirmed that S.sutor visit the Polite and Dividi aggregation sites mostly around the full moon, with the majority of51
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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 44 and 45: were selected. Fish selected for ta
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 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 102 and 103: (a)(b)Fig. 1. Map of (a) study site
Page 104 and 105: Fig. 2. Number of E. lanceolatus ob
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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
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