Bright spots of sustainable shark fishing

Simpfendorfer, Colin A.; Dulvy, Nicholas K.

doi:10.1016/j.cub.2016.12.017

Cited by 213 publications

(225 citation statements)

References 9 publications

(10 reference statements)

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“…Red List Status might be improving for some species (Balazs and Chaloupka, 2004;Dutton et al, 2005;Simpfendorfer and Dulvy, 2017), highlighting that improved knowledge can lead to better management and conservation outcomes. Nonetheless, threats are highest where species aggregate such as to breed or forage (Edgar et al, 2008;Hays et al, 2010) and where species and humans frequently overlap; for marine species this is often in coastal zones .…”

Section: Discussionmentioning

confidence: 99%

Informing Marine Protected Area Designation and Management for Nesting Olive Ridley Sea Turtles Using Satellite Tracking

Dawson

Formia²,

Agamboué³

et al. 2017

Front. Mar. Sci.

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Understanding the horizontal and vertical habitat of olive ridley sea turtles (Lepidochelys olivacea), a threatened species, is critical for determining regions for protection and relevant gear modifications that may effectively reduce bycatch, the largest threat to this species. Satellite transmitters were used to determine the movement and dive behavior of 21 female olive ridley turtles tagged in Pongara National Park, Gabon during the 2012, 2013, and 2015 nesting seasons. A switching state-space model was used to filter the tracking data and categorize the internesting and post-nesting movements. Gridded utilization distribution (UD) home range analysis of tracking data revealed that the entire core habitat occurred in the Komo Estuary during the internesting period. Within the Komo Estuary, 58% of this core UD occurred in shipping lanes. Dive data from the 2015 tagging season revealed that during the internesting period, turtles spent the majority of their time resting on the estuary seabed. Approximately 20% of all dive time was spent on the bottom and all maximum dive depths corresponded to the depth of the seabed, indicating that bottom set gear during the internesting period may pose the greatest potential for fisheries interactions. National parks currently protect many of the nesting sites and the Gabon Bleu initiative has formally designated 10 new marine parks and a network of community and industrial fishing zones; this data was a layer used in determining the park and zone boundaries. Shared use of the estuary by fisheries, shipping, and olive ridley turtles creates a need for management measures to reduce interactions. Thus, the results from this study can further provide detailed information that can be used to support the development of evidence-based management plans.

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Section: Discussionmentioning

confidence: 99%

Informing Marine Protected Area Designation and Management for Nesting Olive Ridley Sea Turtles Using Satellite Tracking

Dawson

Formia²,

Agamboué³

et al. 2017

Front. Mar. Sci.

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“…Because of problems and uncertainty with fisheries data and in data collection systems (e.g. under‐reporting, low coverage), quantifying reliable levels of discards is challenging and some authors suggest levels may actually exceed the reported number of landings by several orders of magnitude (Filmalter et al., ; Gray & Kennelly, ; James et al., ; Pauly & Zeller, ; Simpfendorfer & Dulvy, ; Worm et al., ). Furthermore, compounding the complexity and uncertainty is that there is little or no information on at‐vessel and discard mortality rates for most pelagic species captured and released in different fisheries and gears (references, Table ).…”

Section: Introductionmentioning

confidence: 99%

Meta‐analysis of post‐release fishing mortality in apex predatory pelagic sharks and white marlin

Musyl¹,

Gilman

2019

Fish and Fisheries

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Robust assessments of the effects of fishing require accounting for components of fishing mortality, including post‐release fishing mortality (Fr). Random‐effects meta‐analysis synthesized Fr in seven pelagic shark species captured, tagged and released with 401 pop‐up satellite archival tags compiled from 33 studies and three gears (longline, purse‐seine, rod & reel). The majority of Fr outcomes occurred within days of release, and the summary effect size for Fr was 0.27 [95% CI: 0.19–0.36], ranging from a low pooled effect size of 0.17 for blue shark (Prionace glauca, Carcharhinidae) to 0.38 (silky shark, Carcharhinus falciformis, Carcharhinidae). Fr rates in blue shark were consistent over dissimilar spatial and temporal scales, and results from earlier meta‐analysis were replicated, which is the most powerful way to authenticate results. Condition at tagging was a strong predictor, and dichotomized survival outcomes in silky shark and no sex‐, size‐, location‐ or gear‐specific Fr rates were demonstrated. Meta‐analyses and sensitivity analyses indicated exposure to risk factors and conditions whilst caught on the gear probably had the largest explanatory effect on Fr, rather than stressors incurred during handling and release. Records from 549 tagged istiophorid billfishes (six species, three gears, 43 studies) demonstrated they are more robust to stressors sustained during capture, handling and release than pelagic sharks. Findings from previous meta‐analysis on Fr rates in white marlin (Kajikia albida, Istiophoridae) were replicated. Synthesized Fr rates enable prioritizing approaches to mitigate by‐catch fishing mortality, to improve the quality of stock and ecological risk assessments and to expand our knowledge of factors influencing trophic structure.

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“…Recent progress on stock assessments for sharks is applauded in all tRFMOs; however, indicators of state or fishery impacts do not exist for the majority of sharks, and their status in most cases is unknown or relatively poorly known as the assessment results were considered unreliable. There remains no management for shark species such as Blue and Shortfin mako stocks despite evidence that they are increasingly targeted and catches are rising rapidly (Davidson et al., ; Simpfendorfer & Dulvy, ). We note that the status of oceanic pelagic sharks is highly unfavourable and indeed there are signs that the status of some may be rapidly worsening (Clarke, Harley, Hoyle, & Rice, ; Dulvy et al., ; Gilman, Owens, & Kraft, ).…”

Section: Resultsmentioning

confidence: 99%

Report card on ecosystem‐based fisheries management in tuna regional fisheries management organizations

Juan‐Jordá¹,

Murua²,

Arrizabalaga³

et al. 2017

Fish and Fisheries

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International instruments of fisheries governance have set the core principles for the management of highly migratory fishes. We evaluated the progress of tuna Regional Fisheries Management Organizations (tRFMOs) in implementing the ecological component of ecosystem‐based fisheries management (EBFM). We first developed a best case tRFMO for EBFM implementation. Second, we developed criteria to evaluate progress in applying EBFM against this best case tRFMO. We assessed progress of the following four ecological components: target species, bycatch species, ecosystem properties and trophic relationships, and habitats. We found that many of the elements necessary for an operational EBFM are already present, yet they have been implemented in an ad hoc way, without a long‐term vision and a formalized plan. Overall, tRFMOs have made considerable progress monitoring the impacts of fisheries on target species, moderate progress for bycatch species, and little progress for ecosystem properties and trophic relationships and habitats. The tRFMOs appear to be halfway towards implementing the ecological component of EBFM, yet it is clear that the “low‐hanging fruit” has been plucked and the more difficult, but surmountable, issues remain, notably the sustainable management of bycatch. All tRFMOs share the same challenge of developing a formal mechanism to better integrate ecosystem science and advice into management decisions. We hope to further discussion across the tRFMOs to inform the development of operational EBFM plans.

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Bright spots of sustainable shark fishing

Cited by 213 publications

References 9 publications

Informing Marine Protected Area Designation and Management for Nesting Olive Ridley Sea Turtles Using Satellite Tracking

Informing Marine Protected Area Designation and Management for Nesting Olive Ridley Sea Turtles Using Satellite Tracking

Meta‐analysis of post‐release fishing mortality in apex predatory pelagic sharks and white marlin

Report card on ecosystem‐based fisheries management in tuna regional fisheries management organizations

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