Post-release fishing mortality of blue (Prionace glauca) and silky shark (Carcharhinus falciformes) from a Palauan-based commercial longline fishery

Musyl, Michael K.; Gilman, Eric

doi:10.1007/s11160-018-9517-2

Cited by 34 publications

(85 citation statements)

References 127 publications

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“…Whilst measuring accurate F c rates is largely dependent on the quality of fisheries observer programmes and fleet coverage (Dapp et al., ; Walsh, Bigelow & Sender, ; Walsh, Ito, Kawamoto & McCracken, ), F r can be challenging to estimate due to cost‐benefit and logistics (Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl, Domeier et al, ). It has been hypothesized that F c and F r rates might be expected to show congruence because prognostic factors responsible for F c in fisheries are likely to be many of the same ones acting on F r (Benoît, Hurlbut, Chasse & Jonsen, ; Braccini, Rijn & Frick, ; Campana, Joyce & Manning, ; Dapp et al., , ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ). Though there are several indirect and direct methods to estimate F r rates in pelagic sharks, each method has different strengths and weaknesses which impact cost‐benefit and ultimately experimental design and statistical power (Campana, Joyce, Fowler & Showell, ; Goodyear, ; Graves et al., ; Horodysky & Graves, ; Kerstetter & Graves, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ).…”

Section: Introductionmentioning

confidence: 99%

“…It has been hypothesized that F c and F r rates might be expected to show congruence because prognostic factors responsible for F c in fisheries are likely to be many of the same ones acting on F r (Benoît, Hurlbut, Chasse & Jonsen, ; Braccini, Rijn & Frick, ; Campana, Joyce & Manning, ; Dapp et al., , ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ). Though there are several indirect and direct methods to estimate F r rates in pelagic sharks, each method has different strengths and weaknesses which impact cost‐benefit and ultimately experimental design and statistical power (Campana, Joyce, Fowler & Showell, ; Goodyear, ; Graves et al., ; Horodysky & Graves, ; Kerstetter & Graves, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ). Survival studies to determine F r generally require several hundred samples to achieve statistical power at ~80% (Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Machin, Campbell, Tan & Tan, ; Murray, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ; Ryan, ).…”

Section: Introductionmentioning

confidence: 99%

“…Though there are several indirect and direct methods to estimate F r rates in pelagic sharks, each method has different strengths and weaknesses which impact cost‐benefit and ultimately experimental design and statistical power (Campana, Joyce, Fowler & Showell, ; Goodyear, ; Graves et al., ; Horodysky & Graves, ; Kerstetter & Graves, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ). Survival studies to determine F r generally require several hundred samples to achieve statistical power at ~80% (Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Machin, Campbell, Tan & Tan, ; Murray, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ; Ryan, ). As an example, pop‐up satellite archival tags (PSATs) are commonly used in F r studies but costs of PSATs has translated into small sample sizes (Table ; Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Moyes et al., ; Musyl & Gilman, ; Musyl et al., ; Musyl, Moyes, Brill & Fragoso, ).…”

Section: Introductionmentioning

confidence: 99%

“…Survival studies to determine F r generally require several hundred samples to achieve statistical power at ~80% (Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Machin, Campbell, Tan & Tan, ; Murray, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ; Ryan, ). As an example, pop‐up satellite archival tags (PSATs) are commonly used in F r studies but costs of PSATs has translated into small sample sizes (Table ; Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Moyes et al., ; Musyl & Gilman, ; Musyl et al., ; Musyl, Moyes, Brill & Fragoso, ).…”

Section: Introductionmentioning

confidence: 99%

“…Whilst single F r studies are often context‐specific, they generally are of low power, and thus, their utility is difficult to judge in the framework of mortality outcomes from other studies (Table ; Murray, ; Musyl et al., ). In other words, low power and precision introduces uncertainty in the point estimates and large F r studies are cost‐prohibitive to design at 80% power using electronic tags (Goodyear, ; Horodysky & Graves, ; Kerstetter & Graves, ; Musyl & Gilman, ; Musyl, Brill et al., ; Musyl et al., ). Meta‐analysis is an approach that can help bridge the gap between low power issues, cost‐benefit and has the ability to resolve trends and test multiple hypotheses across multiple independent studies.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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Increasing the functionalities and accuracy of fisheries electronic monitoring systems

Gilman

Legorburu

Fedoruk³

et al. 2019

Aquatic Conservation

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1. Fisheries-dependent data underpin essential scientific and management applications. Electronic monitoring (EM) systems are increasingly being used to supplement human observer programmes and provide coverage where none previously existed.2. Candidate methods were identified to expand EM functionalities to collect data fields of human observer programmes that contemporary EM systems either cannot collect or require improved accuracy. Options were also identified to enable EM systems to collect new data fields that human observers cannot collect, prioritized by scientists, managers and the catch sector. 3. Many EM limitations could be resolved through simple changes of repositioning existing or adding new cameras with suitable fields of view and resolution, integrating additional sensors, and making minor modifications to fishers' practices. Research, development and trials, however, are required for possible EM integration of some existing and emerging technologies. 4. Whether an EM improvement method should be pursued requires consideration of: the relative importance for meeting monitoring objectives; the accuracy and cost of alternative monitoring methods, such as data collection by fishers with EM auditing, and by dockside inspections; impacts on fishing operations and crew safety; and net costs.5. Active support from fishers is necessary for EM collection of some data fields, where EM enables auditing fisher compliance with required procedures. Having EM systems supply data desired by the seafood industry could augment their support for EM and incentivize fisher cooperation.6. EM systems have the capacity to collect most data fields collected by human observer programmes with high precision and in some cases improved accuracy, to supply information of interest to seafood companies, and to meet expanding data requirements as fisheries management frameworks continue to transition to implementing elements of ecosystem-based fisheries management.

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A 40‐year chronology of the vulnerability of spinetail devil ray (Mobula mobular) to eastern Pacific tuna fisheries and options for future conservation and management

Griffiths

Lezama-Ochoa

2021

Aquatic Conservation

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Tuna fisheries are among the largest and most valuable fisheries in the world, but most interact with many non‐target species, including several of high conservation importance. The spinetail devil ray (Mobula mobular) – listed as ‘Endangered’ on the IUCN Red List of Threatened Species – is a commonly discarded bycatch species, particularly in the eastern Pacific Ocean, yet insufficient data exist to undertake a traditional population assessment. A new ecological risk assessment approach designed for data‐limited settings – Ecological Assessment of the Sustainable Impacts of Fisheries (EASI‐Fish) – was used to reconstruct the historical vulnerability status of M. mobular and to simulate potential changes in its status under 45 hypothetical conservation and management measures. These involved various temporal closures of the eastern Pacific Ocean tuna fishery, decreasing post‐capture mortality by improved handling and release practices, and combinations of the two. The species was classified as ‘Least Vulnerable’ between 1979 and 1993, but became ‘Most Vulnerable’ from 1994, which coincided with a rapid spatial expansion of the industrial purse‐seine fishery, and especially from 2011 following the rapid increase in the number of sets made on floating objects. Simulating the conservation and management measures in place in 2018 revealed that 31 of the 45 scenarios resulted in a change in classification of the species to ‘Least Vulnerable’, which primarily involved a reduction of post‐capture mortality by as little as 20%. It is fortuitous in that education of fishers to implement appropriate best handling and release practices is simpler, more rapid and more cost‐effective than the implementation of fishery closures or gear modifications, which can be expensive and complex to implement and monitor and will probably result in substantial reduction in the catches of target species.

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Post-release fishing mortality of blue (Prionace glauca) and silky shark (Carcharhinus falciformes) from a Palauan-based commercial longline fishery

Cited by 34 publications

References 127 publications

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

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

Increasing the functionalities and accuracy of fisheries electronic monitoring systems

A 40‐year chronology of the vulnerability of spinetail devil ray (Mobula mobular) to eastern Pacific tuna fisheries and options for future conservation and management

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