scholarly journals Discard mortality played a major role in the loss of 10 billion juvenile scallops in the Mid-Atlantic Bight: Reply to Hart & Shank (2011)

2011 ◽  
Vol 443 ◽  
pp. 299-302 ◽  
Author(s):  
KDE Stokesbury ◽  
JD Carey ◽  
BP Harris ◽  
CE O’Keefe
Keyword(s):  
Discard Mortality

scholarly journals Convergence of a Disease and Litigation Leading to Increased Scallop Discard Mortality and Economic Loss in the Georges Bank Fishery

2019 ◽  
Vol 39 (2) ◽  
pp. 299-306 ◽  
Author(s):  
Kevin D. E. Stokesbury ◽  
N. David Bethoney ◽  
Daniel Georgianna ◽  
Susan Inglis ◽  
Emily Keiley
Keyword(s):  
Economic Loss ◽  
Georges Bank ◽  
Discard Mortality

Estimating discard mortality using meta-analysis and fishery-dependent sampling

2021 ◽  
Vol 240 ◽  
pp. 105962
Author(s):  
P.J. Rudershausen ◽  
S.J. Poland ◽  
J.H. Merrell ◽  
C.B. Pelletier ◽  
C.S. Mikles ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Discard Mortality

The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions

2011 ◽  
Keyword(s):  
Mortality Rate ◽  
Regulatory System ◽  
The United States ◽  
Minimum Size ◽  
Summer Flounder ◽  
Discard Mortality ◽  
Stock Assessments ◽  
Dead Fish ◽  
Size Limits ◽  
Intermediate Performance

<i>Abstract</i> .—Summer flounder <i>Paralichthys dentatus </i> supports an important recreational fishery along the northeastern coast of the United States. Successful rebuilding of the stock and the need to constrain landings within total-allowable-landing targets has resulted in declining bag limits, increasing size limits, higher discarding, and a reduction in satisfaction derived from recreational fishing trips. A series of fishing trips were observed in which alternative regulatory scenarios were tested to identify approaches to better optimize bag limits and size limits. The alternatives included a slot limit in which some smaller fish were allowed to be landed, a reduced minimum size, and a cumulative size, in which the bag limit and size limit were conflated such that fish take was controlled by the cumulative size of the landed fish. Comparisons were made to fishing trips conducted under 2006 regulations that produced higher injury frequencies than other regulatory scenarios due to discarding of larger fish that tended to be gut-hooked. Two alternatives performed significantly better in terms of reducing the potential for discard mortality among discarded fish, the slot-limit and the cumulative-size scenarios. An intermediate performance of the reduced-minimum-size scenario was due to an increased proportion of dead fish, but this association was unexplained. Fish uninjured save for minor hook damage were common on all vessels and in all fishing approaches. Injury frequency was, in fact, remarkably low, less than half of the assumed discard mortality rate in presentday stock assessments. The study supports the use of size-specific mortality rates for fish discarded recreationally. The study offers no support for the efficacy of the 2006 regulatory system in controlling discard mortality rate. Any of the alternative plans is an improvement, but the slot-limit and cumulative-size scenarios are deserving of the most scrutiny.

scholarly journals Using a double codend to reduce discard mortality

2009 ◽  
Vol 66 (10) ◽  
pp. 2077-2081 ◽  
Author(s):  
Matt K. Broadhurst ◽  
Russell B. Millar ◽  
Sebastian S. Uhlmann
Keyword(s):  
Cloud Cover ◽  
Marine Science ◽  
Total Catch ◽  
Fishing Mortality ◽  
Short Term ◽  
Discard Mortality ◽  
Conventional Design ◽  
Gear Selectivity ◽  
Negative Impacts

Abstract Broadhurst, M. K., Millar, R. B., and Uhlmann, S. S. 2009. Using a double codend to reduce discard mortality. – ICES Journal of Marine Science, 66: 2077–2081. Traditional technical strategies for mitigating collateral fishing mortality have involved improving gear selectivity (to reduce bycatch) and, more recently, concomitant changes to onboard handling procedures to reduce some of the negative impacts to the remaining discards. A less common approach is to modify gears physically to minimize deleterious catching mechanisms and subsequent mortalities during fishing. This study aimed to investigate the utility of the latter category of modifications for penaeid trawls by separating a codend into two compartments (termed a double codend) to alleviate interactions between catches. Compared with a conventional design, the double codend significantly reduced the immediate (from 17.1 to 13.8%) and short-term (22.5 to 17.1%) mortalities of discarded juvenile school prawns (Metapenaeus macleayi). The effectiveness of the double codend remained independent of other factors known to affect the fate of discarded juvenile M. macleayi, including cloud cover and, owing to minimal variability, the weight of the total catch. However, irrespective of the codend configuration, overall mortalities were also positively correlated with the quantity of jellyfish. We conclude that when combined with modifications to improve selectivity and appropriate onboard handling strategies, compartmentalizing codend catches could cumulatively reduce unaccounted fishing mortality.

scholarly journals Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish

2007 ◽  
Vol 64 (8) ◽  
pp. 1535-1542 ◽  
Author(s):  
M. W. Davis
Keyword(s):  
Mortality Rates ◽  
Mortality Data ◽  
Second Phase ◽  
Fish Stocks ◽  
Fishing Vessels ◽  
Discard Mortality ◽  
Delayed Mortality ◽  
Mortality Predictors ◽  
Sigmoid Functions

Abstract Davis, M. W. 2007. Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish. – ICES Journal of Marine Science, 64: 1535–1542. Development of efficient methods to predict discard and escapee mortality in fishing operations is essential to the conservation of sensitive fish stocks. For a few fisheries, mortality data are available from fishing experiments in the field; these require long-term holding or monitoring of fish in tanks, cages, or tag and recapture experiments to detect delayed mortality. A different approach to predicting discard and escapee mortality is to use reflex action mortality predictors (RAMP) consisting of relationships between mortality and reflex impairment for species of interest. Fish were towed in a net in the laboratory and then either restrained in foam-lined holders and rapidly tested for reflex impairment five minutes after towing, or held for up to 60 days to determine delayed mortality. Delayed mortality occurred up to 20 days after towing. RAMP was related to mortality with biphasic sigmoid functions. As fishing stressors increased in intensity, the first phase showed an increase in RAMP with no concomitant mortality. In the second phase, RAMP continued to increase, while mortality became apparent and increased. The measurement of RAMP in restrained fish on board fishing vessels during experiments to predict discard mortality and in caged free swimming fish to predict escapee mortality is feasible and advisable.

Estimating the Discard Mortality of Atlantic Cod in the Southern Gulf of Maine Commercial Lobster Fishery

2020 ◽  
Vol 40 (5) ◽  
pp. 1252-1262
Author(s):  
B. B. Sweezey ◽  
C. W. Capizzano ◽  
J .A. Langan ◽  
H. P. Benoît ◽  
E. W. Hutchins ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Discard Mortality ◽  
Lobster Fishery

scholarly journals Estimating and mitigating the discard mortality of Atlantic cod (Gadus morhua) in the Gulf of Maine recreational rod-and-reel fishery

2016 ◽  
Vol 73 (9) ◽  
pp. 2342-2355 ◽  
Author(s):  
Connor W. Capizzano ◽  
John W. Mandelman ◽  
William S. Hoffman ◽  
Micah J. Dean ◽  
Douglas R. Zemeckis ◽  
...  
Keyword(s):  
Best Practice ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Related Factors ◽  
Discard Mortality ◽  
Recreational Fishery ◽  
Receiver Array ◽  
Management Plans

Abstract In recent years, the recreational contribution to the total catch of Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) has increased with recreational discards outnumbering recreational landings by 2:1. However, the discard mortality (DM) rate of cod released in the recreational fishery remains poorly understood, thus contributing to the uncertainty in stock assessments and fishery management plans. The current study examined the capture-related factors most detrimental to cod DM in the GOM recreational rod-and-reel fishery. Atlantic cod (n = 640; 26.0–72.0 cm) were angled from June–October 2013 on southern Jeffreys Ledge in the western GOM using fishing gear representative of the local recreational fishery. A subset (n = 136) was also tagged with pressure-sensing acoustic transmitters before being released into an acoustic receiver array (n = 31) deployed to monitor survival up to 94 days. To properly model DM up to the fishery-wide level, all cod were visually assessed for capture-related injuries according to a four-level injury score index. Mean tackle-specific DM rates of 15.4 and 21.2% were estimated for bait- and jig-captured cod, respectively, with an overall 16.5% mean DM rate for the 2013 GOM recreational cod fishery. Twenty-nine cod tagged with acoustic transmitters were identified as dead, where the majority (∼90%) died within 16 h post-capture. Upon evaluation with a specifically adapted parametric survival analysis, greater incidence of mortality was attributed to the capture and handling process (rather than release) for moderately and severely injured cod. Based on the capture-related factors associated with the highest injury rates, we recommend minimizing fight and handling times, avoiding areas with small cod, educating inexperienced anglers, and favouring bait over jigs to mitigate mortality. Results will continue to inform the development of fishery management plans and enhance survival through dissemination of “best practice” techniques to fishery stakeholders.

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