Intraspecific demography of the silky shark (Carcharhinus falciformis): implications for fisheries management

Grant, Michael I., Smart, Jonathan J., Rigby, Cassandra L., White, William T., Chin, Andrew, Baje, Leontine, and Simpfendorfer, Colin A. (2020) Intraspecific demography of the silky shark (Carcharhinus falciformis): implications for fisheries management. ICES Journal of Marine Science, 77 (1). pp. 241-255.

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Abstract

The silky shark (Carcharhinus falciformis) is one of the most heavily fished tropical shark species globally, and currently there is increasing concern for its conservation status. However, large differences and ambiguity in life history parameter estimates among regions complicates its conservation and fisheries management. Using a Leslie matrix model that incorporated stochastic effects, we analysed the intraspecific demography of C. falciformis using available life history data from seven regions. Among regions, large differences were observed in generation time and age-specific reproductive contributions. Carcharhinus falciformis generally had low resilience to fishing mortality (F) throughout its distribution. Age-at-first-capture and age-at-last-capture management approaches resulted in substantial differences among regions. This was largely influenced by age-at-maturity. However, in scrutinizing some regional life history studies, it is likely that sampling design and methodological differences among regions have resulted in inaccuracies in life history parameter estimates and subsequent demographic attributes. This implies that age and life-stage-dependent management approaches using these possibly inaccurate life history parameters may be inappropriate. We suggest that a greater emphasis needs to be placed on eliminating human sources of error in elasmobranch life history studies to ensure management for wide-ranging species, such as C. falciformis, is most effective.

Item ID: 62631
Item Type: Article (Research - C1)
ISSN: 1054-3139
Keywords: conservation, demographic models, fisheries management, life history, pelagic sharks, sustainable fisheries
Copyright Information: © International Council for the Exploration of the Sea 2019. All rights reserved.
Funders: Papua New Guinea National Fisheries Authority (PNGNFA), CSIRO Oceans and Atmosphere, Australian Centre for International Agricultural Research (ACIAR)
Projects and Grants: ACIAR project FIS/2012/102
Date Deposited: 25 Mar 2020 07:37
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050205 Environmental Management @ 100%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960501 Ecosystem Assessment and Management at Regional or Larger Scales @ 100%
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