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Effectiveness of Venting and Descender Devices at Increasing Rates of Postrelease Survival of Black Sea Bass

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Effectiveness of Venting and Descender Devices at Increasing Rates of Postrelease Survival of Black Sea Bass

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Abstract

We tested the ability of venting and descender (recompression) devices to increase the relative survival of released Black Sea Bass Centropristis striata, a physoclistous reef species with high discard rates in hook‐and‐line fisheries that operate in the U.S. Atlantic Ocean and Gulf of Mexico. We caught fish via hook and line from waters that were 38 m deep, a depth where Black Sea Bass often exhibit signs of barotrauma and may be unable to submerge after release. Fish were conventionally tagged and vented with either an 11‐gauge cannula or a 16‐gauge needle, descended using a descender (recompression) device, or released as tagged controls (no venting or recompression). Tests of independence were used to determine the relationship between submergence and treatment (excluding recompressed fish) as well as between submergence and tag return rate. Tag‐recapture data were used to inform a Cox proportional hazards model that evaluated the survival of fish treated with each experimental device relative to the control group. A significantly greater proportion of fish submerged when treated with either venting device relative to the controls, and the fish that submerged had a greater proportion of tag returns relative to those that did not submerge. Venting and recompression increased postrelease survival compared with the controls. The results provide guidance to managers who seek methods to reduce discard mortality rates in hook‐and‐line fisheries for this important species. Future studies should examine the use of these devices at a range of depths to determine their effectiveness.

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... Lutjanus campechanus (Drumhiller et al. 2014;Bohaboy et al. 2019), Pacific rockfishes Sebastes spp. (Theberge and Parker 2005), Black Sea Bass Centropristis striata (Rudershausen et al. 2020), and deepwater groupers . Studies testing this technique have generally found increases in survival of fish released with a descender device as compared to without (reviewed by Eberts and Somers 2017). ...
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From June 2009 through December 2012 fishery observers were placed on charter and headboat vessels operating in the Gulf of Mexico to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. The objective of this study was to relate injuries and impairments measured directly from gags Mycteroperca microlepis caught and released within the recreational fishery to subsequent mark-recapture rates. Due to the large spatial and temporal scales of the study design, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Also, changes in fishing effort following the Deepwater Horizon oil spill during 2010 in the Gulf of Mexico and drastically reduced recreational harvest seasons for gag during 2011 and 2012 were unanticipated during the design of this study. Therefore, it was necessary to control for potential covariates on encounter and recapture rates for gags tagged in different regions, different years, and different times of year. This analysis demonstrates the utility of the Cox regression proportional hazards model in comparing relative survival among gags released in various conditions while controlling for potential covariates on both the occurrence and timing of recapture events. A total of 3954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 m were in fair or poor condition. Relative survival was significantly reduced (alpha <0.05) for gags released in fair and poor condition after controlling for variable mark-recapture rates among regions and across months and years when tagged fish were initially captured and released. Gags released within the recreational fishery in fair and poor condition were only 66.4% (95% C.I. 46.9–94.0%) and 50.6% (26.2–97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at 10 m depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1–25.2%) in shallow depths to 30 m, to 35.6% (5.6–55.7%) at depths greater than 70 m (p < 0.001, R2 = 0.917)
Article
Although some anglers regularly deflate swim bladders of demersal fishes being released, it is not known whether this practice actually increases postrelease survival of reef fishes. Benefits of deflating the swim bladder of black sea bass Centropristis striata and vermilion snapper Rhomboplites aurorubens before release were evaluated; survival of fishes deflated with one of two tools was compared to survival of nondeflated controls. Capture depths were 20–22 m, 29–35 m, and 43–55 m. Fishes were deflated with a 16-gauge hypodermic needle (99 black sea bass, 64 vermilion snapper) or with a Sea Grant tool consisting of a sharpened stainless steel canula (119 black sea bass, 64 vermilion snapper). Deflated fish were held in cages and observed in situ for 24 h. Controls (108 black sea bass, 89 vermilion snapper) were first segregated in a live well and then held in situ for 24 h in cages. Deflation, especially with the hypodermic needle, provided very significant reductions in mortality of black sea bass, and benefits of deflation increased with capture depth. Deflation for vermilion snapper was also beneficial, but to a lesser extent. Comparison of control results with a previous study using identical methods suggests that ascent speed may affect survival. Deflation of black sea bass and vermilion snapper by hypodermic needle is recommended for scientists. For anglers the Sea Grant tool may be a better choice; it is commonly used to apply dart-type tags and is readily available from some natural resources agency's tagging programs. Because the results differed for the two species, further study is needed to determine whether to recommend deflation as a standard practice for all reef fishes.
Article
The mortality of discarded fish bycatch is an important issue in fisheries management and, because it is generally unmeasured, represents a large source of uncertainty in estimates of fishing mortality worldwide. Development of accurate measures of discard mortality requires fundamental knowledge, based on principles of bycatch stressor action, of why discarded fish die. To date, discard mortality studies in the field have focused on capture stressors. Recent laboratory discard experiments have demonstrated the significant role of environmental factors, size- and species-related sensitivity to stressors, and interactions of stressors, which increase mortality. In addition, delayed mortality was an important consideration in experimental design. The discard mortality problem is best addressed through a combination of laboratory investigation of classes of bycatch stressors to develop knowledge of key principles of bycatch stressor action and field experiments under realistic fishing conditions to verify our understanding and make predictions of discard mortality. This article makes the case for a broader ecological perspective on discard mortality that includes a suite of environmental and biological factors that may interact with capture stressors to increase stress and mortality.
Article
The analysis of censored failure times is considered. It is assumed that on each individual are available values of one or more explanatory variables. The hazard function (age‐specific failure rate) is taken to be a function of the explanatory variables and unknown regression coefficients multiplied by an arbitrary and unknown function of time. A conditional likelihood is obtained, leading to inferences about the unknown regression coefficients. Some generalizations are outlined.
Book
Summary The authors estimate that between 17.9 and 39.5 million tons (average 27.0 million) of fish are discarded each year in commercial fisheries. These estimates are based on a review of over 800 papers. The highest quantities of discards are from the Northwest ...
Article
Fishes captured and brought to the surface by commercial and recreational fishers may suffer a variety of injuries that collectively are referred to as barotrauma. To relieve barotrauma symptoms, particularly those associated with an expanded swim bladder, some anglers deflate, or vent, the swim bladder (or body cavity when the swim bladder has ruptured) of fishes before releasing them. I compiled 17 studies that assessed the potential benefits of venting in 21 fish species and 1 composite group. These studies provided 39 sample estimates that compare survival (N = 18) and recapture rates (N = 21) of vented and unvented fish. I used relative risk to summarize results of individual studies, which allowed me to combine results from experimental and capture-recapture studies. Overall, there was little evidence that venting benefited fish survival. Venting was equally ineffective for freshwater and marine fishes and its efficacy was unaffected based on whether venting was performed by fishery biologists or anglers. The effects of venting did vary with capture depth: venting was slightly beneficial to fish captured from shallow waters, but appeared to be increasingly harmful for fish captured from progressively deeper waters. The available evidence suggests that venting fish should not only be discouraged by fishery management agencies, but given the possibility that venting may adversely affect survival of fish captured from deep water, this practice should be prohibited, rather than required by regulation.
Article
The effectiveness of deepwater release at improving the 17-d survival of discarded yelloweye rockfish Sebastes ruberrimus was determined by comparing an estimate of survival for individuals released at depth with an estimate of submergence probability for individuals released at the water's surface. A mark–recapture study was used to generate a maximum likelihood estimate of the 17-d survival probability of yelloweye rockfish (n = 182) caught by hook and line (depth = 18–72 m) and subsequently released at depth. The average Cormack–Jolly–Seber survival probability for yelloweye rockfish released at depth was remarkably high (0.988; 95% confidence interval = 0.478–0.999) and positively correlated with individual total length. Survival probability was not significantly influenced by the range of capture depths explored in this study or by exposure to barotrauma and other capture stressors. The submergence success of yelloweye rockfish released at the water's surface was 0.221 (95% confidence interval = 0.149–0.315), suggesting that the maximum survival potential of individuals released at the surface is low. The results of this study indicate that the average survival of discarded yelloweye rockfish can be substantially improved by deepwater release.Received March 25, 2011; accepted June 22, 2011
Article
Abstract  Common coral trout, Plectropomus leopardus Lacepède, crimson snapper, Lutjanus erythropterus Bloch, saddletail snapper, Lutjanus malabaricus (Bloch & Schneider), red emperor, Lutjanus sebae (Cuvier), redthroat emperor, Lethrinus miniatus (Schneider) and grass emperor, Lethrinus laticaudis Alleyne & Macleay, were tagged to determine the effects of barotrauma relief procedures (weighted shot-line release and venting using a hollow needle) and other factors on survival. Release condition was the most significant factor affecting the subsequent recapture rate of all species. Capture depth was significant in all species apart from L. malabaricus and L. miniatus, the general trend being reduced recapture probability with increasing capture depth. Recapture rates of fish hooked in either the lip or mouth were generally significantly higher than for those hooked in the throat or gut. Statistically significant benefit from treating fish for barotrauma was found in only L. malabaricus, but the lack of any negative effects of treating fish indicated that the practices of venting and shot-lining should not be discouraged by fisheries managers for these species.
Article
Abstract  Minimum size limits may be ineffective for reef fishes because they often sustain barotrauma when caught from deep (>20 m) waters. A study was undertaken in conjunction with hook-and-line commercial fishermen to calculate discard percentages and evaluate potential release mortality of eight economically important species: black sea bass, Centropristis striata (Linnaeus), red grouper, Epinephelus morio (Valenciennes), snowy grouper, Epinephelus niveatus (Valenciennes), gag, Mycteroperca microlepis (Goode and Bean), scamp, Mycteroperca phenax (Jordan and Swain), vermilion snapper, Rhomboplites aurorubens (Cuvier), white grunt, Haemulon plumieri (Lacepède) and red porgy, Pagrus pagrus (Linnaeus). Fishing with baited hook and line occurred in 2004 and 2005 in Onslow Bay, NC, in waters 19–150 m deep. Sub-legal discard rates were 15% for vermilion snapper, 25% for red porgy, 7% for red grouper, 33% for gag, 35% for scamp and 12% for black sea bass. Although mortality based on post-release behaviour was relatively low, higher mortalities estimated from models incorporating hooking location and depth of capture suggest that minimum size limits may not provide the population benefits intended by management in the North Carolina reef fishery.
Article
Abstract  Catch-and-release angling is a well-established practice in recreational angler behaviour and fisheries management. Accompanying this is a growing body of catch-and-release research that can be applied to reduce injury, mortality and sublethal alterations in behaviour and physiology. Here, the status of catch-and-release research from a symposium on the topic is summarised. Several general themes emerged including the need to: (1) better connect sublethal assessments to population-level processes; (2) enhance understanding of the variation in fish, fishing practices and gear and their role in catch and release; (3) better understand animal welfare issues related to catch and release; (4) increase the exchange of information on fishing-induced stress, injury and mortality between the recreational and commercial fishing sectors; and (5) improve procedures for measuring and understanding the effect of catch-and-release angling. Through design of better catch-and-release studies, strategies could be developed to further minimise stress, injury and mortality arising from catch-and-release angling. These strategies, when integrated with other fish population and fishery characteristics, can be used by anglers and managers to sustain or enhance recreational fishing resources.
Assessing the effects of line capture and barotrauma relief procedures on post‐release survival of key tropical reef fish species in Australia using recreational tagging clubs
  • W. D. Sumpton
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Release methods for rockfish
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Theberge, S., and S. Parker. 2006. Release methods for rockfish. Oregon State University, Oregon Sea Grant, Report ORESU-G-05-001, Corvallis.
GMFMC (Gulf of Mexico Fishery Management Council)
GMFMC (Gulf of Mexico Fishery Management Council). 2007. Amendment 27 to the reef fishery management plan. GMFMC, Tampa, Florida.
Descender devices are promising cannulas for increasing survival in deepwater groupers. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science
  • B J Runde
  • J A Buckel
Runde, B. J., and J. A. Buckel. 2018. Descender devices are promising cannulas for increasing survival in deepwater groupers. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science [online serial] 10:1007-1117.