Fate of deep-hooked white-spotted charr after cutting the line in a catch-and-release fishery

Tsuboi, Jun‐ichi; Morita, Kentaro; Ikeda, Hisatoshi

doi:10.1016/j.fishres.2006.03.002

Cited by 38 publications

(47 citation statements)

References 13 publications

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“…Similarly, most of the postrelease mortality in white marlin was associated with gut-hooked fish (Horodysky & Graves 2005). The internal injuries associated with gut-hooking were not evaluated in this study, but must have been more extensive than those reported for white-spotted charr Salvelinus leucomaenis, where gut-hooked fish experienced > 90% post-release survival (Tsuboi et al 2006). Nevertheless, it is clear that the blue shark mortality associated with gut-hooking was due to trauma, rather than interference with digestion and subsequent starvation; the survival time models indicated that if sharks were going to die after release, one-half would die in less than 1 d, and that 95% would die within 11 d. Such a short period of survival is inconsistent with death by starvation, which would presumably take many weeks.…”

Section: Discussionmentioning

confidence: 99%

Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags

Campana¹,

Joyce²,

Manning³

2009

Mar. Ecol. Prog. Ser.

157

155

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Blue sharks Prionace glauca are the most frequently discarded fish species during commercial pelagic longline fishing operations worldwide, yet their post-release mortality rate has never been measured. A generalized linear model of 12 404 blue sharks observed during the Canadian Atlantic pelagic longline swordfishery suggested a hooking mortality of 12 to 13%, yet scientific examination of 902 of these sharks indicated that hooking mortality was actually higher. A random sample of 40 of these blue sharks were tagged with satellite pop-up archival transmission (PAT) tags, then monitored for periods of up to 6 mo after release. All of the surviving sharks exhibited a depthholding recovery behaviour for a period of 2 to 7 d after release. All healthy sharks survived, while 33% of those that were badly injured or gut hooked subsequently died. Overall blue shark bycatch mortality in the pelagic longline fishery was estimated at 35%, while the estimated discard mortality for sharks that were released alive was 19%. Survival time models indicated that 95% of the mortality occurred within 11 d of release, indicative of death by trauma rather than starvation. The annual blue shark catch in the North Atlantic was estimated at about 84 000 t, of which 57 000 t is discarded. A preliminary estimate of 20 000 t of annual dead discards for North Atlantic blue sharks is similar to that of the reported nominal catch, and could substantially change the perception of population health if incorporated into a population-level stock assessment. KEY WORDS: Discard mortality · Hooking mortality · Tagging · Bycatch · Satellite tags Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 387: [241][242][243][244][245][246][247][248][249][250][251][252][253] 2009 ronmental conditions at the time of release (Davis 2002). The difficulty in quantifying post-release mortality is due to the scarcity and/or expense of methods for tracking released fish in the wild over periods of time of up to several months. Most studies have attempted to avoid this issue by holding fish in cages or pens for several days after capture (e.g. Neilson et al. 1989). However, holding pens provide a clearly artificial and spatially constrained environment, and thus have the potential to introduce (or avoid) sources of mortality that would not be present under natural, free-swimming conditions. As a result, some sort of tag-recapture or telemetry program is required to properly estimate the post-release mortality rate of discarded fish (Davis 2002, Pollock & Pine 2007, Skomal 2007. Such a program would be well suited for monitoring released fish in the wild for extended periods of time, and has been successfully applied in estimating short-term discard mortality rates in large pelagic fish such as striped marlin (Tetrapturus audax) (Domeier et al. 2003). An additional advantage of such studies is that evidence of physical trauma or stress indicators from blood chemistry can ultimately be linked to the subsequent s...

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Section: Discussionmentioning

confidence: 99%

Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags

Campana¹,

Joyce²,

Manning³

2009

Mar. Ecol. Prog. Ser.

157

155

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“…Consequently, the studies suffer from small sample sizes and little power. Two recent studies (Tsuboi et al 2006;Wilde and Sawynok unpublished) were explicitly designed to identify means of increasing survivorship in deeply hooked fish. Wilde and Sawynok (unpublished) examined capture and recapture records (n = 248,010) for 27 species of Australian fish.…”

Section: Cutting Line If Deeply Hookedmentioning

confidence: 99%

“…Based on these findings, Wilde and Sawynok (unpublished) concluded that there was no clear benefit to removing hooks from deeply hooked fish. Tsuboi et al (2006) cut the line and left the hook embedded in 77 deeply hooked white-spotted char during a 10-week period. Of these, 93.5% were recaptured, and in many cases the hooks were corroded or had been evacuated (Tsuboi et al 2006).…”

Section: Cutting Line If Deeply Hookedmentioning

confidence: 99%

“…Tsuboi et al (2006) cut the line and left the hook embedded in 77 deeply hooked white-spotted char during a 10-week period. Of these, 93.5% were recaptured, and in many cases the hooks were corroded or had been evacuated (Tsuboi et al 2006). These findings support the notion that cutting the line is a safe alternative to removing the hook in deeply hooked fish.…”

Section: Cutting Line If Deeply Hookedmentioning

confidence: 99%

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Do Catch-and-Release Guidelines from State and Provincial Fisheries Agencies in North America Conform to Scientifically Based Best Practices?

Pelletier

Hanson

Cooke

2007

Environmental Management

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Many recreational anglers practice catchand-release angling, where fish are returned to the water with the presumption that they will survive. However, not all fish survive, and those that do often experience sublethal consequences including injury and stress. There is compelling scientific evidence that angler behavior and gear choice can affect the success of catch-and-release as a management and conservation strategy. Because anglers often look to government natural resource agencies for guidance on how to handle and release fish properly, there is a need to assess whether their outreach materials are readily accessible and provide the necessary and correct information on the subject. Therefore, on-line catchand-release guidelines developed by state and provincial natural resource agencies across North America were evaluated to determine whether their guidelines were consistent with the best available scientific information. This analysis revealed that there was immense variation in the depth and breadth of coverage among jurisdictions. Agency guidelines contradicted one another in several areas including air exposure, angling in deep water, venting trapped gases, and resuscitation. In many cases, the guidelines failed to provide sufficient direction to actually be of use to anglers or provide direction consistent with contemporary scientific literature. This analysis will assist with developing outreach materials that promote sustainable recreational fisheries and in maintaining the welfare status of individual fish.

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“…by cutting the line and releasing the fish), they are limited to very short monitoring periods. The few primary literature studies that have examined more longer-term consequences of leaving ingested hooks in fish are mainly limited to salmonids (but see Aalbers et al 2004, Tsuboi et al 2006, and support a general pattern whereby most mortalities occur within the first 24 h after release, followed by ongoing hook ejection from surviving fish over up to 2 mo (Hubert & Engstrom-Heg 1980, Schill 1996, Schisler & Bergersen 1996. For example, Schill (1996) observed that 47% of released hook-ingested rainbow trout Oncorhynchus mykiss died and 74% of the surviving fish ejected their hooks over 60 d. Similarly, Schisler & Bergersen (1996) reported mortalities of approximately 21% and a hook ejection rate of 25% over 21 d for the same species.…”

Section: Introductionmentioning

confidence: 99%

Ingestion and ejection of hooks: effects on long-term health and mortality of angler-caught yellowfin bream Acanthopagrus australis

Broadhurst¹,

Butcher²,

Brand³

et al. 2007

Dis. Aquat. Org.

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Ninety juvenile yellowfin bream Acanthopagrus australis were angled from holding tanks, allowed to ingest nickel-plated, carbon-steel J-hooks and released (with their lines cut) into individual experimental tanks during 2 experiments in order to assess their (1) long-term (up to 105 d) health, mortality and rate of hook ejection and (2) short-and medium-term (< 42 d) temporal changes in health during hook ingestion. Equal numbers of control fish were scooped from holding tanks and similarly monitored in experimental tanks. Of 20 hook-ingested fish released during Expt 1, 3 died within 8 d, providing a non-significant mortality of 15%. Between Day 6 and Day 56 post-release, 13 of the surviving individuals ejected their hooks, which were typically oxidized to about 94% of their original weight and often broken into 2 pieces. At Day 105, there were no significant differences between the 20 control and 17 hook-ingested/-ejected fish in terms of their ability to digest and assimilate food (measured as changes in apparent digestibility coefficients), stress (measured as concentrations of plasma cortisol and glucose) or of morphological parameters that included weight (Wt) and maximum height (MH), maximum width (MW) and maximum girth (MG). During Expt 2, 3 individuals that still contained ingested hooks and 3 controls were sampled on each of 9 occasions between Day 3 and Day 42 post-release. All fish were sampled for blood cortisol and glucose and were then euthanized before being weighed and measured for total length (TL), MH, MW and MG. Hook-ingested individuals were also X-rayed to determine the position and orientation of hooks. There were no significant differences in plasma glucose between hook-ingested and control fish. Irrespective of the treatment of fish, concentrations of cortisol were elevated on some sampling occasions, indicating variable, acute stress. The MH and MG of fish were not significantly different between groups. Significant differences were detected for MG and Wt, with hook-ingested fish having weights similar to those of the control fish but a relatively greater MW (owing to stomach distension from ingested hooks) until 2 wk post-release, after which both morphological parameters generally declined. There was no significant temporal progression of hooks in the stomach of treatment fish; however, some hooks reorientated to positions that may have precluded passage along the digestive tract. We conclude that, for the J-hooks examined, cutting the line is an appropriate strategy that results in the greater majority of released hook-ingested yellowfin bream surviving with minimal negative long-term effects. KEY WORDS: Acanthopagrus australis · Catch-and-release · Hook mortality · Hook ingestionResale or republication not permitted without written consent of the publisher

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Fate of deep-hooked white-spotted charr after cutting the line in a catch-and-release fishery

Cited by 38 publications

References 13 publications

Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags

Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags

Do Catch-and-Release Guidelines from State and Provincial Fisheries Agencies in North America Conform to Scientifically Based Best Practices?

Ingestion and ejection of hooks: effects on long-term health and mortality of angler-caught yellowfin bream Acanthopagrus australis

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