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The post-release behavior and fate of tournament-caught smallmouth bass after ‘fizzing’ to alleviate distended swim bladders
Abstract
In recreational fishing, barotrauma occurs when fish that are angled from deep water are rapidly brought to the surface, causing a number of injuries and physiological alterations associated with gas expansion (such as distended swim bladders) that may impede swimming and prevent the fish from returning to depth. By deflating the swim bladder using a hypodermic needle (a process called “fizzing”) fish typically can return to depth. However, little is known about its consequences and efficacy on wild fish. At a competitive smallmouth bass (Micropterus dolomieu) angling event on Rainy Lake in northwestern Ontario, we evaluated the effects of post-weigh in fizzing on the behaviour and short-term survival of three treatment groups after release: (i) barotrauma fish without fizzing (N = 8); (ii) barotrauma fish that were fizzed (N = 9); (iii) fish without signs of barotrauma that were fizzed (N = 10) (sham control). Small external radio transmitters were affixed to the fish and tracked for 4 days. Fish were released at a common site and we assessed their dispersion at specific distances from the release site (50, 250, and 2000 m). All fish survived the 4-day monitoring period. No differences were observed in the time it took each group to disperse from the release site. Furthermore, there was no statistical evidence that fizzing influenced mean daily movements relative to controls, though a consistent trend was noted where fish that were fizzed displayed greater movement than non-fizzed fish with distended swim bladders. This study revealed that fizzing by trained experts is not detrimental to barotrauma fish. However, if done improperly there is risk to vital organs suggesting that there is merit in exploring other less invasive approaches to recompressing fish. Because our statistical power was generally low, further research is needed to determine whether fizzing should be encouraged or dissuaded to maintain the welfare status of the fish, decrease sublethal impairments, and reduce mortality.
... The reduction in gas volume in the swim bladder reduces buoyancy, ostensibly allowing the fish to submerge and return to a depth of neutral pressure. There is considerable debate over the appropriateness of venting due to its invasive nature and potential to cause additional damage to the fish (e.g., piercing of organs) or mediate introduction of external pathogens into the body cavity (Kerr 2001;Nguyen et al. 2009;Scyphers et al. 2013). In addition, Wilde (2009) previously reviewed the effectiveness of venting and found no consistent benefit for postrelease survival in comparison with no treatment. ...
... However, it is currently unclear which methods actually provide an accurate perspective on RR. Intuitively, ex situ experiments should provide a direct and controlled means of monitoring survival accurately (e.g., Keniry et al. 1996;Shasteen and Sheehan 1997;Drumhiller et al. 2014) in comparison with tag-andrecapture studies, which introduce much more uncertainty as well as a lag time for recapture events (Nguyen et al. 2009;Curtis et al. 2015). Telemetry studies have only recently emerged in the literature on barotrauma relief; this method FIGURE 2. Box-and-whisker plot of relative risk (RR) values extracted from studies assessing the effectiveness of barotrauma relief techniques by using various assessment methods: bathy cages (n = 32), ex situ (n = 18), tag and recapture (n = 18), and telemetry (n = 8). ...
... Note that for clarity, the highest observed RR value (31.0) is excluded from the figure. provides a means of direct monitoring in the natural environment and offers the potential to examine behavioral changes in addition to survival (Nguyen et al. 2009;Butcher et al. 2013;Curtis et al. 2015). Bathy cages, which are various forms of containment pens, did not significantly influence RR values despite being the most common approach used (Roach et al. 2011). ...
Descending fish to depths of neutral buoyancy is a promising, less-invasive alternative to swim bladder venting for relieving barotrauma and reducing mortality in sport fish. However, we lack a broad perspective on the relative benefits of these two approaches. We reviewed the most up-to-date literature to evaluate the effectiveness of venting compared to descending treatments. Mean relative risk (RR) based on 76 published comparisons (51 marine, 25 freshwater; 18 genera, 28 species) showed that venting (2.0 ± 4.7 [mean ± SD]) and descending (1.6 ± 1.4) both had positive effects on survival (RR ≥ 1.1). However, RR was generally small and statistically indistinguishable between treatments, providing no strong support for the use of one method over the other. Modeling of factors affecting RR showed that the study design variable “assessment method” was the only important factor affecting RR, having a larger influence on survival than habitat, capture depth, or treatment type (venting versus descending). Biotelemetry and ex situ methods produced significantly higher estimates of RR than other assessments. Our review suggests that the two major approaches to barotrauma relief do not differentially influence survival outcomes and that study design may be an important source of bias. Consequently, we recommend that managers consider barotrauma relief options carefully on a case-by-case basis, and we encourage additional research on sublethal endpoints in addition to mortality.
Received November 29, 2016; accepted March 9, 2017
... Lorsque les individus sont remontés rapidement des grandes profondeurs (pêche au filet ou à la ligne), un problème de décompression rapide peut être occasionné. Il engendre alors une surproduction de gaz dans la vessie natatoire et les vaisseaux sanguins (Nguyen, Gravel et al. 2009). Cette vessie natatoire augmente alors brutalement de volume et le poisson est incapable d'avoir un équilibre de nage correct. ...
... L'immersion du poisson sous l'eau permet de bien vérifier que des gaz s'échappent de la vessie. Le positionnement optimal du site de « fizzing » variant selon les espèces, il est primordial avant toute intervention de s'informer et de pratiquer sur l'espèce ciblée (Nguyen, Gravel et al. 2009). Lorsque le « fizzing » ne peut être pratiqué, un relâcher immédiat du poisson, plutôt qu'une stabulation, peut diminuer les risques de dommages physiologiques mais n'éliminera pas les effets de la décompression rapide (Nguyen, Gravel et al. 2009). ...
... Le positionnement optimal du site de « fizzing » variant selon les espèces, il est primordial avant toute intervention de s'informer et de pratiquer sur l'espèce ciblée (Nguyen, Gravel et al. 2009). Lorsque le « fizzing » ne peut être pratiqué, un relâcher immédiat du poisson, plutôt qu'une stabulation, peut diminuer les risques de dommages physiologiques mais n'éliminera pas les effets de la décompression rapide (Nguyen, Gravel et al. 2009). ...
Aquatic ecosystem functioning in human-impacted environments is highly dependent of its uses; in consequence, the environment of biological communities is generally fluctuating. Studying the link between environment and organism in fluctuating environments is generally more complex compared to steady environments. The main objective of this work was to better understand how fish populations respond to environmental modifications in a reservoir affected with water level fluctuations (WLF), the Bariousses’s reservoir located on the Vézère River.
A multiscale approach was used with different biological (community and individual) and temporal (annual and daily cycles) scales. A special attention was given to the littoral zone as it plays a key role for lake fish communities and since it is strongly affected by WLF. This work is divided in 4 parts. The first part presents the characteristics of the study site and the second part describes the impact of WLF on the studied habitats using a mapping of the littoral zone. The consequences of hydrological stress through the changes in habitat conditions were also analyzed as well as the effects of water temperature and photoperiod. The third part shows the effect of the temporal variability of environmental conditions induced by WLF on the composition of the littoral fish community (sampled by electrofishing). The fourth part presents an innovative positioning system acoustic telemetry (Vemco Positioning System) that was used to study the impact of WLF at the individual scale by analyzing the behavior of 90 individuals from three different fish species (pikeperch, pike and perch) with a satisfactory accuracy (average error of 3.3 m after filtration).
The results of this work showed that WLF induced a temporal variability of the littoral zone surface and volume. In addition, a gradual decrease of the structural complexity of littoral habitats was associated with lower water level inducing a trend to homogenization (dominance of thinner substrates without vegetation). Despite these changes in habitats conditions induced by WLF, littoral fish community did not show any clear change in composition. High inter-individual variability of behavioral responses was observed in response to environmental fluctuations, but the temperature and photoperiod were the two major structural parameters controlling fish activity and spatial distribution. Water level affected a part of the fish population since more individuals attended the littoral zone and were less mobile when available habitats were more complex (with a high water level).
These results allowed us to suggest some ideas for the management of water levels in the studied reservoir focused on the fish population.
Keywords: reservoir, fish, littoral zone, water level fluctuations, temperature, photoperiod, individuals.
... Most studies that have assessed the effects of barotrauma in teleosts have used laboratory-based hyperbaric chambers (Shasteen & Sheehan, 1997;Parker et al., 2006), field-based tagging (mark-recapture or biotelemetry) (Bruesewitz et al., 1993;Nguyen et al., 2009) or confinement experiments (Render & Wilson, 1994;Diamond & Campbell, 2009). Of these methods, mark-recapture and biotelemetry tagging provide the most holistic assessment of the fate of released fishes. ...
... Of these methods, mark-recapture and biotelemetry tagging provide the most holistic assessment of the fate of released fishes. The former relies on accurate returns from anglers and both approaches are often very expensive, which can mean low replication and difficulty in differentiating mortality from barotrauma from other cumulative catch-and-release effects (Nguyen et al., 2009;Sumpton et al., 2010). In contrast, although hyperbaric chambers can isolate the effects of barotrauma and assess the utility of mitigation methods across adequate replication and under controlled conditions, such studies are logistically difficult and considerably removed from natural environments (Shasteen & Sheehan, 1997). ...
... Under such conditions, the severity of barotrauma may increase and render fish positively buoyant, with the potential of sustaining further physical damage through contact with conspecifics and the top of the live well. Equally important, tournament fishes are almost always eventually released in shallow water at the lakes' edge where compromised buoyancy would expose them to increased predation, exposure or boat traffic (Keniry et al., 1996;Nguyen et al., 2009). For such individuals, the only viable option may be venting immediately after capture, although clearly anglers need to be educated about the correct techniques and the size of venting needles needs to be appropriate for the species to minimize injuries. ...
The effects of barotrauma on the short-term mortality and physical condition of Australian bass Macquaria novemaculeata were investigated after being: (1) conventionally angled and released during two tournaments in deep impoundments and (2) released untreated or subjected to venting or recompression during a manipulative experiment. All fish were released into two 20 m deep bathy-cages and monitored for 3 days. Of 238 M. novemaculeata angled during the tournaments, 43 (18·1%) had clinical signs of barotrauma or were vented and five of these later died (11·6% mortality). Catch histories varied significantly between both barotrauma and non-barotrauma fish and tournaments, but only hook ingestion significantly influenced mortality (P < 0·05). During the manipulative experiment, venting significantly influenced mortality (13·3%) compared to no treatment or recompression (no deaths). Magnetic resonance images and dissections of barotrauma fish indicated large variation among clinical signs. On the basis of these results, wherever possible M. novemaculeata suffering barotrauma should be immediately released with no treatment. Fish that are unable to resubmerge should be recompressed, while those held in live wells and released in shallow water should be vented.
... All known studies to date on the effects of barotrauma on fish have been conducted on species considerably smaller than swordfish, such as snappers, groupers and emperors Bennett, 2005, Sumpton et al., 2010); smallmouth bass Micropterus dolomieu (Nguyen et al., 2009), drums (Butcher et al., 2013) and rockfishes (Jarvis and Lowe, 2008). While the principles by which barotrauma is detrimental to other physoclistous fishes are the same for swordfish, due to their size, unique physiology and depth at which they are targeted, there are unique factors that should be considered regarding implications of these symptoms for the species. ...
... For smaller fishes, lateral venting (removing air through an external puncture; Kerr, 2001, Eberts andSomers, 2017) and weighted descending devices (Sumpton et al., 2010;Bellquist et al., 2019) are used in the attempt to ameliorate the effects of barotrauma and allow fish to return to depth. However, the use and effectiveness of venting is contentious (Nguyen et al., 2009;Wilde, 2009), and for neither technique should efficacy for swordfish be assumed without validation. One of the fish that presented with mild distension mentioned above that was able to dive after release died four days later after a period of unusual rapid night-time fluctuations in depth, perhaps reflecting internal damage to the swim bladder. ...
Swordfish (Xiphias gladius) are large, economically and ecologically important predatory fish with a wide circumglobal distribution. While swordfish are coveted by anglers, development of recreational fisheries has been limited historically, due in part to the species’ tendency to migrate into the mesopelagic zone during the day, effectively out of reach of typical game fishing methods. Recently, however, the adoption of ‘deep-dropping’, targeting swordfish during daytime with baits at > 300 m depth, has expanded access to the fish and led to the emergence of new regional fisheries. In 2014 a deep-dropping recreational swordfish fishery emerged in temperate southeast Australia and attracted international attention after yielding several swordfish line-class weight records. However, information is needed to guide best practices for emerging deep-dropping swordfish fisheries. Here, we present the first assessment of capture-related morbidity and post-release survival of swordfish caught by deep-dropping in southeast Australia. Among swordfish assessed to be in suitable condition for release, affixed pop-up satellite archival tags indicated 85.6% (57.8 – 95.7%; n = 13) survived after release. Including swordfish assessed as moribund after attempted resuscitation as mortalities, the survival rate for landed swordfish was 44% (95% CI 25.1 – 64.8%; n = 25). Severe abdominal distension (a notably protruding abdomen presumably due to swim bladder overinflation) and observed internal hooking injury (in the gut or gill area) were strong predictors of reduced survival (odds ratios 0.008 and 0.015 respectively), while angling duration and fish weight did not have a discernible effect on mortality. While the swordfish fishery is superficially like more common istiophorid billfish game fishing, the unique physiology and behaviour of swordfish and depths at which they are targeted present a unique challenge for stewardship as the typical catch-and-release billfish game fishing ethos may not be appropriate. The results of this preliminary study suggest swordfish caught deep-dropping are a poor candidate for purely catch-and-release angling. Predictors of post-release mortality are readily observable, so fishers should be prepared to humanely dispatch fish exhibiting symptoms of injury from gill or gut hooking, or abdominal distension severe enough to prevent the fish from righting itself beyond a brief resuscitation period.
... For physoclistous fishes (species lacking a duct between their swim bladder and alimentary tract) rapid ascent from depth causes gasses within the swim bladder to expand rapidly, potentially causing small tears in the swim bladder that allows gasses to enter the viscera and cranium, resulting in a condition known as barotrauma (Gotshall, 1964). Fish suffering from barotrauma may become positively buoyant and struggle to return to depth, inhibiting dispersion and leaving fish vulnerable to surface predation, light exposure, and high temperatures (Collins, 1996;Bruesewitz et al., 1993;Nguyen et al., 2009;McLennan et al., 2014). Anglers can assess barotrauma visually by noting a bulging of the body cavity, prolapsed alimentary tract either from the buccal cavity or anus, exopthalmia, cutaneous hemorrhaging, and/or excessive bouyancy (Gotshall, 1964;Feathers and Knable, 1983;Butcher et al., 2013;McLennan et al., 2014;Ferter et al., 2015). ...
... Wilde (2009) argues that the potential to perforate organs and additional tearing of tissue associated with puncturing through the side of the fish outweigh perceived positive effects. Conversely, other studies have indicated little to no mortality is caused by venting and suggest it as a viable recovery method (e.g., Wilson and Burns, 1996;Nguyen et al., 2009;McLennan et al., 2014). However, studies assessing the efficacy of venting as a recovery tool often look at short-term mortality (i.e., days rather than weeks). ...
... Wider implementation of commercially available descending devices may combat fish mortality by return-ing fish to a depth that allows them to relieve barotrauma pressure (Curtis et al. 2015;Bellquist et al. 2019;Davies et al. 2022;Louison et al. 2023). These devices are an alternative to more invasive methods such as fizzing which has the potential to harm vital organs if done improperly (Kerr 2001;Nguyen et al. 2009;Drumhiller et al. 2014). Further research should explore the efficacy of descending devices to relieve barotrauma in lake trout during winter months. ...
We examined behaviour and physiology of lake trout (Salvelinus namaycush) following ice-angling. Fish were ice-angled and placed in a water-filled tub for 0.5, 4, and 6h to recover (n=19). Reflex impairment and physiological status were assessed repeatedly for every individual. Longer fight times lead to higher lactate and glucose, and lower extracellular pH 0.5h post-angling. Loss of orientation was the most common reflex impairment (84% of fish) 4h post-angling. Mortality (36.8%) was observed during the study; however, variation in handling, barotrauma, and issues with sampling may have confounded angling effects. To determine if barotrauma impacted impairment and mortality, lake trout at a later sampling date (n=29) were exposed to air for either 60, 120, 180, 240, 300, or 420s before assessment (3.4% mortality). For fish air exposed for 300s or more, 14% lost orientation during immediate assessment. Bloating occurred in 20% of fish air exposed for 60s. An air exposure duration of 420s significantly impaired reflexes. Recreationally caught lake trout show behavioural and physiological impairment with such impairments magnified by extended air exposure.
... Although freshwater drum do not have many natural aquatic predators in the Red River watershed, they may be especially vulnerable to avian predation (e.g., by American white pelicans [Pelecanus erythrorhynchos]), particularly if the fish floats along the surface of the water following release. Once the orientation reflex is lost, mortality by avian predation is a potential outcome as they are unable to submerge themselves out of sight (Ross and Hokenson, 1997;Jarvis and Lowe, 2008;Nguyen et al., 2009;Raby et al., 2014;Brownscombe et al., 2017). Given this vulnerability to predation, it is possible that fish lacking the orientation reflex in our study did not survive upon release. ...
Many catch-and-release angling events involve air exposure and exhaustive exercise that elicit a physiological stress response, and depending on a variety of factors, delayed mortality is a possible outcome. There have been ample studies in this area, however, significant gaps exist in the literature for species that are targeted by more specialized anglers, such as freshwater drum (Aplodinotus grunniens). We quantified physiological and reflex responses in freshwater drum following angling, across seasons. Once a fish was on the line, the fight duration and time exposed to air were varied to account for differences in angler skill level (fight time range: 5 s to 2 min; air exposure range: 20 s to 3 min). Location and severity of injury were determined, blood biopsies were taken to quantify physiological stress, and reflex impairment was assessed. Thirty-one percent of fish captured were deeply hooked in the esophagus tissue. Freshwater drum experienced a disruption in homeostasis as blood glucose, plasma cortisol, and plasma lactate increased significantly from baseline values following angling. Additionally, seasonal differences were observed for blood glucose and plasma cortisol as higher values were observed in the summer when compared to the spring. The ‘orientation’ reflex was the most frequently impaired (29 % of fish lacked this reflex), but impairment did not differ seasonally. Because freshwater drum have the largest latitudinal range of any North American freshwater fish and are being targeted more frequently by anglers as of late, it is important to fill this knowledge gap regarding their responses to angling events to develop best practices for anglers to promote conservation. The wide distribution of freshwater drum may also make them a candidate model species for addressing the convergence between assessing the impacts of catch-and-release angling and other environmental issues facing freshwater fishes, such as climate change.
... Wilde (2009) argues that the potential for damaging organs and the likelihood of further tearing of the tissue associated with perforation from the edge of the fish are more severe than the positive effects. However, he showed that the death caused by the use of this method was low and suggested that there was a healing method (Wilson and Burns, 1996;Nguyen et al., 2009;McLennan et al., 2014). ...
The aim of this study is to analyze the barotrauma treatment performance of different fish release devices and its effects on different fishing operations. Experiments were carried out between September 2017 and April 2018 in the Iskenderun Bay, located in the Eastern Mediterranean. Fishing Release Hook (FRH), Fish Release Clamp (FRC) and Fish Release Basket (FRB) were tested in three different fishing activities, which are longline, hand line and bottom trawl fishery, respectively for Epinephelus aeneus, Epinephelus costae and Nemipterus randalli. They were released into the sea after fishing operations. Study results showed that fish release devices were very effective for barotrauma treatment. The use of FRB is suitable for bottom trawl fishing, while the use of FRH and FRC is more ergonomic in longline and hand line fishery.
... Venting, also known as "fizzing" or "needling, " consists of puncturing the swim bladder with a hypodermic needle to release the expanded gas before it can cause damage to internal organs. Although this technique can be employed successfully, there is risk of unintentional damage to neighboring organs, necrosis at the puncture site, and potential bacterial infection from repeated punctures and/or reused needles (Nguyen et al., 2009;Drumhiller et al., 2014;Munday et al., 2015). Divers or manned submersibles will occasionally stage fishes for decompression stops at intermediate depths in baskets, buckets or other enclosures, retrieving them later (Munday et al., 2015). ...
Accompanying the recent technological innovations in remotely operated vehicles (ROVs), submersibles, technical SCUBA, and closed-circuit rebreather diving gear, new discoveries are being made on mesophotic coral ecosystems around the world. However, collecting live fishes from mesophotic depths (60–150 m) is challenging, given the difficulty of accessing the habitat, catching the fishes, and the barotrauma that can result from rapid decompression during their transport to the surface. Here, we designed and tested the performance of a portable, submersible hyperbaric chamber, the SubCAS, which we used to safely surface reef fishes from mesophotic depths. During six expeditions between 2014 and 2017 to the Philippines, Vanuatu, Palau and Pohnpei, we assessed the survival of 174 fishes caught between 60 and 150 m depth and decompressed using this chamber. A total of 155 (89.1%) fishes survived decompression, and 143 of 148 specimens shipped (96.6%) survived air cargo transport from remote field sites to the Steinhart Aquarium at the California Academy of Sciences. Survival was significantly related to taxonomic family, with Pomacentridae and Apogonidae showing the highest mortality. Collection depth, fish body size, and length of decompression had no relation to survivorship. Significant interactions between individual decompression events and both fish body size and taxonomic family indicate that low survival was associated with specific SubCAS trials. The SubCAS has allowed us to reliably surface charismatic fishes previously unknown to science and maintain them in aquaria for research and public engagement purposes. This opportunity facilitates a direct connection between our more than one million annual visitors and the wonders of exploration and the science of mesophotic coral ecosystems.
... Many bycatch species have no economic value and are discarded in the sea. Survival rate of these individuals is questionable because of the physiological effects that decompression causes when they are removed from great depths and brought rapidly to the surface (Nguyen, 2009). Species with the highest resistance to this practice belong to families Ariidae, Sciaenidae, and Haemulidae. ...
A pesca de arrasto de camarão produz mais descarte do que qualquer outra pescaria e captura uma grande quantidade de indivíduos imaturos. Esta pesquisa visa determinar a sustentabilidade da captura da ictiofauna acompanhante na pesca de arrasto de camarão. Cada espécie foi analisada de acordo com dois grupos de critérios: (1) vulnerabilidade à captura pela rede de arrasto e mortalidade ocasionada por esta pescaria; e (2) capacidade de recuperação da população para minimizar. Dentro de cada critério as espécies foram classificadas de 1 a 3, sendo 1 o valor mais alto, indicando que a espécie é altamente susceptível à captura ou tem baixa capacidade de recuperação. Um total de 8.894 indivíduos foram capturados, pertencendo a 28 famílias. As espécies com captura menos sustentável foram Stellifer rastrifer e Isopisthus parvipinnis. Estas espécies são altamente susceptíveis, pois são bentônicas ou demersais e suas dietas incluem organismos bentônicos. Chirocentrodon bleekerianus e Anchoa tricolor foram as espécies que apresentaram a captura mais sustentável. Por serem pelágicas, são menos susceptíveis à captura por arrastos de fundo, além disto, apresentaram uma grande capacidade de recuperação, pois a maior parte dos indivíduos capturados encontrava-se acima do seu tamanho de primeira maturação sexual. Devido à natureza multiespecífica da pescaria é difícil implementar medidas mitigatórias específicas. Assim, a criação de zona de exclusão de pesca deve ser considerada como a medida de manejo mais adequada.
... Similarly, a prolapsed cloaca and ruptured swim bladder could lead to detrimental bacterial infections and in some cases, possibly septicaemia with associated mortality [31]. Further, beyond organ displacement and possible disruptions to blood supply, overexpansion of the swim bladder can cause ongoing buoyancy problems that could impair normal swimming behaviour, rendering fish less efficient at feeding and more susceptible to predation and exposure to sunlight [9,32]. ...
In response to concerns regarding the potential for sub-lethal impacts of barotrauma on reproductively active Chrysophrys auratus during catch and release, 90 males and 90 females representing five reproductive stages (immature or resting-28%, developing-8%, developed-7%, ripe or spawning-23% and spent-34%) were angled from 8-70 m and macroscopically assessed (on-board and then in a laboratory). Irrespective of sex, all fish exhibited various clinical signs of barotrauma, including a prolapsed cloaca (60% of fish); gastric herniation (46%); ruptured swim bladder (73%); organ displacement (48%); and kidney (3%), liver (73%) and coloemic-cavity haemorrhaging (33%);with the frequency of nearly all positively associated with capture depth. Reproductive stage was also an important barotrauma predictor (reflecting related morphological changes) with a general trend towards spent fish least likely to incur the various clinical signs-especially for a prolapsed cloaca (also common among immature or resting fish and significantly affected by food in the digestive tract) and a ruptured swim bladder (common among ripe or spawning fish). The only macroscopically visible gonad damage was haemorrhaging, which was least common among immature or resting and spent fish and, irrespective of reproductive stage, temporally reduced in frequency, and more quickly among males than females. While further research is required to accurately describe the effects of angling at each stage of the reproductive cycle and the physiological consequences of barotrauma on the gonads of C. auratus, given the observed influences of reproductive stage and depth on barotrauma found in this study, any adverse effects might be partially managed by regulating either temporal or spatial fishing effort.
... Crucially, a distended swim bladder can prevent fish from returning to depth, where shelter from predators is afforded. Fish with distended or ruptured swim bladders floating at the surface after capture are extremely vulnerable to predation from aquatic and avian predators (Ross and Hokenson 1997; Jarvis and Lowe 2008; Nguyen et al. 2009 ). Gitschlag and Renaud (1994) concluded that postrelease survival of red snapper (L. ...
The assumption that animals released from fishing gears survive has frequently been scrutinized by researchers in recent years. Mortality estimates from these research efforts can be incorporated into management models to ensure the sustainability of fisheries and the conservation of threatened species. Post-release mortality estimates are typically made by holding the catch in a tank, pen or cage for short-term monitoring (e.g. 48 h). These estimates may be inaccurate in some cases because they fail to integrate the challenges of the wild environment. Most obvious among these challenges is predator evasion. Stress and injury from a capture experience can temporarily impair physiological capacity and alter behaviour in released animals, a period during which predation risk is likely elevated. In large-scale commercial fisheries, predators have adapted their behaviour to capitalize on impaired fishes being discarded, while in recreational catch-and-release fisheries, exercise and air exposure can similarly impede the capacity for released fish to evade opportunistic predators. Owing to the indirect and often cryptic nature of this source of mortality, very few studies have attempted to document it. A survey of the literature demonstrated that <2% of the papers in the combined realms of bycatch and catch-and-release have directly addressed or considered post-release predation. Future research should combine field telemetry and laboratory studies using both natural and simulated predation encounters and incorporate physiological and behavioural endpoints. Quite simply, predation is an understudied and underappreciated contributor to the mortality of animals released from fishing gears.
... Point-of-care devices provide a convenient method to assess the effects of commercial and recreational fishing on a number of fish species. The effects of catch-and-release angling and barotrauma have been assessed mainly using glucose and lactate levels as indicators of stress, as well as Hct and Hb in smallmouth and largemouth bass (Micropterus salmonides; Gravel and Cooke, 2008;Hanson et al., 2008;White et al., 2008;Nguyen et al., 2009;Thompson et al., 2012) Field and laboratory-based experiments as well as aquaculture facility practices generally require fish handling. As such, the physiological effects of fish manipulation have been assessed in a number of studies using POC devices. ...
Non-human vertebrate blood is commonly collected and assayed for a variety of applications, including veterinary diagnostics and physiological research. Small, often non-lethal samples enable the assessment and monitoring of the physiological state and health of the individual. Traditionally, studies that rely on blood physiology have focused on captive animals or, in studies conducted in remote settings, have required the preservation and transport of samples for later analysis. In either situation, large, laboratory-bound equipment and traditional assays and analytical protocols are required. The use of point-of-care (POC) devices to measure various secondary blood physiological parameters, such as metabolites, blood gases and ions, has become increasingly popular recently, due to immediate results and their portability, which allows the freedom to study organisms in the wild. Here, we review the current uses of POC devices and their applicability to basic and applied studies on a variety of non-domesticated species. We located 79 individual studies that focused on non-domesticated vertebrates, including validation and application of POC tools. Studies focused on a wide spectrum of taxa, including mammals, birds and herptiles, although the majority of studies focused on fish, and typical variables measured included blood glucose, lactate and pH. We found that calibrations for species-specific blood physiology values are necessary, because ranges can vary within and among taxa and are sometimes outside the measurable range of the devices. In addition, although POC devices are portable and robust, most require durable cases, they are seldom waterproof/water-resistant, and factors such as humidity and temperature can affect the performance of the device. Overall, most studies concluded that POC devices are suitable alternatives to traditional laboratory devices and eliminate the need for transport of samples; however, there is a need for greater emphasis on rigorous calibration and validation of these units and appreciation of their limitations.
... One method for assessing the fate of released fish that has increased in popularity over the past decade is biotelemetry (Nichol and Chilton 2006, Gravel and Cooke 2008, Nguyen et al. 2009). Although not used to assess locally angled-and-released A. japonicus, conspecifics have been tagged with acoustic transmitters and tracked in a southeastern Australian estuary to determine their key habitat and home ranges (Taylor et al. 2006). ...
Two experiments were conducted to quantify the mortality of, and clinical signs of barotrauma to, Argyrosomus japonicus after retrieval from 20 m following either ‘no treatment’, ‘venting’ (a needle inserted into the swim bladder) or ‘recompression’ (released with a weighted line). In Experiment 1, 10 fish were hauled from 20 m and from 5 m (controls) and euthanised for assessment. The only effect on controls was a distended coelomic cavity, but all fish retrieved from 20 m had this symptom and a prolapsed cloaca, and many had haemorrhaging (81%), gastric herniation (70%), swimbladder rupture (50%) and affected buoyancy (66%). Another 20 fish were subjected to the treatments and, along with controls (from 5 m), were released into ‘bathy-cages’ (2.5 m × 20 m) for three days. Only two fish retrieved from 20 m died (total mortality of 3.3%). In Experiment 2, six fish retrieved from 20 m and three control fish were tagged with acoustic transmitters, released following the abovementioned treatments into the wild and monitored for 214 d. All fish with barotrauma remained at shallower depths than controls for the first 10 d, after which behaviour was similar among groups. Our findings are positive, but further research is required to explore the relationship between retrieval depth and the severity of barotrauma.
... Furthermore, tournament-induced mortality has previously been shown to correlate positively with water temperature (Wilde 1998) and high mortality and physiological disturbances have been reported during summer tournaments when water temperatures are at their apex (Schramm et al 1987; Weathers and Newman 1997; Neal and Lopez-Clayton 2001; Gilliland 2002; Wilde et al. 2002a; Wilde et al. 2002b; Suski et al. 2003; Jamison et al. 2007). Fall tournaments may also present unique challenges to angled fish because even though water and air temperatures are low, barotrauma is frequently reported during the fall (relative to other seasons) and can negatively affect the survival, behavior, and physiology of black bass (Morrissey et al. 2005; Gravel and Cooke 2008; Nguyen et al. 2009). Seasonal changes in biotic (e.g. ...
Several environmental stressors can impact the physiology and survival of fishes. Fish experience natural fluctuations in temperature and dissolved oxygen, but variations in these parameters due to anthropogenic sources are typically greater in magnitude and duration. Changes in temperature and oxygen of anthropogenic origins may therefore have larger negative impacts on fish than those occurring during natural events. Physiological parameters are sensitive indicators of the impacts of stressors by providing insight into the manner in which fish are disturbed by the stressor. Fish may display cumulative physiological responses to successive stressors, but the concept of synergy among multiple thermal stressors is poorly understood. Further, some fish species can be subjected to competitive angling events, which expose fish to an array of additional stressors that can increase mortality. The impacts of these events may change over seasons as fish display seasonal changes in behavior and physiology. Latitudinal origin may also affect the physiological response and mortality of fish exposed to common environmental stressors as individual populations are adapted to local environmental conditions. This thesis focuses on addressing these potential impacts on physiological parameters and mortality of largemouth bass (Micropterus salmoides) and provides implications for management and conservation. Largemouth bass were relatively robust to abrupt changes in temperature and oxygen, but were perturbed from physiological homeostasis during large (12°C) temperature shocks and low (< 4 mg O2/L) levels of dissolved oxygen. Cumulative physiological impacts of multiple cold shocks were only slightly greater than the disturbances sustained during a single cold shock, suggesting largemouth bass are able to tolerate successive thermal stressors. Largemouth bass exhibited seasonal changes in physiological parameters but the responses of fish to angling tournaments were relatively similar across seasons when compared with seasonal controls. Mortality was low during angling tournaments held during four seasons and no apparent seasonal trends were observed. Lastly, largemouth bass from two latitudinally separated populations exhibited differences in their physiological responses to acute cold stressors and overwinter mortality, characterized by greater mortality and physiological disturbances of southern fish than northern fish. Knowledge gained from this study can be used to make management and conservation decisions regarding a host of environmental factors and provides insight into the mechanisms by which fish species can persist over large latitudinal ranges.
Black bass Micropterus spp. in North America are commonly targeted by recreational anglers participating in catch‐and‐release angling tournaments. In deeper waterbodies, Smallmouth Bass Micropterus dolomieu are often caught from depths greater than 6 m and held in a boat’s livewell until they are weighed‐in. Smallmouth Bass caught from such depths typically display symptoms of barotrauma, where the swim bladder becomes overinflated and fish cannot maintain proper orientation. We examined the effects of three common practices used by tournament anglers holding fish that exhibit symptoms of barotrauma; no treatment, weighted fin clips (rubber‐coated weighted alligator clips), and fizzing (venting the swim bladder with a hypodermic needle). After receiving a treatment, Smallmouth Bass were held in experimental livewells for a period of three hours and their condition was monitored using reflex action mortality predictors (RAMP). Smallmouth Bass condition declined for fish with no treatment while both fin clips and fizzing demonstrated improved fish condition. Fizzing was also found to be a more rapid and effective treatment than fin clips. As the weight and capture depth of fish in the control group increased, there was a significant decrease in final condition, as indicated by reflex impairment. For tournaments which hold fish in livewells prior to release, these results demonstrate that interventions shortly after capture can effectively reduce reflex impairment in Smallmouth Bass experiencing barotrauma and that fizzing is more effective than fin clips.
Each year, over 45 countries export 30 million fish from coral reefs as part of the global marine ornamental aquarium trade. This catch volume is affected by collection methods that cause mortality. Barotrauma caused by forced ascent of collected fish from depth has been determined to be a cause of post-collection mortality. The detrimental effects of barotrauma can be prevented by decompression, or mitigated with venting (puncturing the swim bladder to release expanded internal gas). To further evaluate the effects of collection methods on fish stress and mortality, we conducted the first comprehensive study on the effects of barotrauma prevention and mitigation practices on marine ornamental fish. We examined the effects of three ascent treatments, each with decompression stops of different frequency and duration coupled with or without venting, on sublethal effects and mortality in yellow tang ( Zebrasoma flavescens ), using histology and serum cortisol measurements. In Z. flavescens subjected to ascent without decompression stops or venting, a mean post-collection mortality of 6.2% occurred within 24h of capture. Common collection methods in the fishery, ascent without or with one decompression stop followed by venting, resulted in no mortality. Histopathologic examination of heart, liver, head kidney, and swim bladder tissues in fish 0d and 21d post-collection revealed no significant lesions in any treatment group. Ascent without decompression stops resulted in significantly higher serum cortisol than ascent with many decompression stops, and venting alone did not affect cortisol. Future work should examine links in the supply chain following collection to determine if further handling and transport stressors affect survivorship and sublethal effects.
Each year, over 45 countries export 30 million fish from coral reefs as part of the global marine ornamental aquarium trade. This catch volume is partly influenced by collection methods that cause mortality. Barotrauma in fish resulting from forced ascent from depth can contribute to post-collection mortality. However, implementing decompression stops during ascent can prevent barotrauma. Conversely, venting (puncturing the swim bladder to release expanded internal gas) following ascent can mitigate some signs of barotrauma like positive buoyancy. Here, we evaluate how decompression and venting affect stress and mortality in the Yellow Tang (Zebrasoma flavescens). We examined the effects of three ascent treatments, each with decompression stops of varying frequency and duration, coupled with or without venting, on sublethal effects and mortality using histology and serum cortisol measurements. In fish subjected to ascent without decompression stops or venting, a mean post-collection mortality of 6.2% occurred within 24 h of capture. Common collection methods in the fishery, ascent without decompression stops coupled with venting, or one long decompression stop coupled with venting, resulted in no mortality. Histopathologic examination of heart, liver, head kidney, and swim bladder tissues in fish 0d and 21d post-collection revealed no significant barotrauma- or venting-related lesions in any treatment group. Ascent without decompression stops resulted in significantly higher serum cortisol than ascent with many stops, while venting alone did not affect cortisol. Future work should examine links in the supply chain following collection to determine if further handling and transport stressors affect survivorship and sublethal effects.
In the current study, we simulated different components of a live-release angling tournament (angling, live-well confinement, and weigh-in) to determine the relative physiological significance of these tournament components for largemouth bass Micropterus salmoides. Our results indicated that depletions of white muscle energy stores and accumulations of muscle lactate (i.e., a large metabolic disturbance) are the most important consequences of live-release angling tournaments for largemouth bass. This study also showed that there are two distinct components of a live-release tournament that cause a metabolic disturbance in largemouth bass: angling and the weigh-in. While the physiological consequences of angling are already well understood, this is the first study to show that the weigh-in portion of a live-release tournament also causes a large anaerobic disturbance in largemouth bass. In our simulation, the weigh-in resulted in a 75% decrease in white muscle phosphocreatine, a 46% decrease in ATP, and a 62% decrease in glycogen relative to control largemouth bass. The weigh-in simulation also caused the lactate concentration in white muscle to increase by about sevenfold relative to control fish and resulted in significant changes to cardiac function. Based on these results, subsequent experiments were performed to determine the main factor(s) responsible for the metabolic disturbance that results from the weigh-in. These experiments demonstrated that the period of air exposure during the weigh-in was a major cause of this disturbance. We recommend that tournament organizers minimize the air exposure that largemouth bass receive during the weigh-in to improve the physiological condition of released tournament-caught fish.
Decompression can be an important problem for fish that are rapidly brought to the surface. The main objectives of this study were to (1) examine the incidence of external signs of decompression in smallmouth bass Micropterus dolomieu after live-release angling tournaments on lakes with different depths, (2) determine the physiological changes in smallmouth bass that exhibit external decompression signs, and (3) identify the best methodological approaches for evaluating this type of disturbance. Our results indicate that decompression does not cause problems for smallmouth bass when tournaments are held on relatively shallow lakes. However, when tournament anglers have access to deep water (>5 m), significant numbers of smallmouth bass may exhibit decompression signs after these events. Decompression signs include swim bladder overinflation, increased plasma lactate, and increased activity of tissue enzymes in plasma. Tournament-caught smallmouth bass exhibiting external signs of decompression also experience internal physiological changes, including significant elevations in the plasma levels of intracellular enzymes (lactate dehydrogenase [LDH]; enzyme number 1.1.1.27; creatine phosphokinase [CPK]; 2.7.3.2; and aspartate aminotransferase [AST]; 2.6.1.1), red blood cell lysis, and a larger anaerobic disturbance after the weigh-in than observed in nondecompressed smallmouth bass. Additional laboratory experiments indicate that plasma AST activity may be the most useful indicator of the extent of tissue damage in decompressed smallmouth bass because it is highly correlated to plasma LDH and CPK levels but is not influenced by the blood sampling method.
Simple and portable methods for assessing the physiological state of channel catfish Ictalurus punctatus would be valuable tools in field situations where problems with blood storage and transportation occur. This study compared the use of handheld lactate and glucose meters with established laboratory methods in stressed (fatigued) and unstressed (control) channel catfish fingerlings. The results obtained from the Accutrend (Roche Diagnostics Corp.) lactate meter and the Accu-Chek Advantage (Roche Diagnostics) glucose meter were consistently lower (P < 0.05) than those obtained with the laboratory reference method. However, significant differences (P < 0.0001) were found between the control and fatigued fish for both lactate and glucose, regardless of the method of analysis. Both handheld meters were found to be reliable and suitable for use in field or laboratory situations where relative measurements are acceptable. The costs associated with using the handheld meters were higher than those associated with accepted laboratory methods; however, the initial capital investment was lower for the handheld meters. Ease of use, portability, and rapidity of sample analysis make the handheld meters attractive alternatives to traditional laboratory methods.
Much research on the fish physiological consequences of tournaments has been conducted to date and has provided anglers and tournament organizers with strategies for reducing stress and mortality. However, one aspect of tournaments that has received little attention is barotrauma. At a fall competitive angling event on Rainy Lake in northwestern Ontario, we evaluated the incidence of barotrauma among tournament-caught smallmouth bass Micropterus dolomieu; we then tagged and released a subset of fish that had severe barotrauma indicators and compared physiology, postrelease behavior, and fate between these fish and those with negligible signs of barotrauma. Overall, 76% of fish had at least one sign of barotrauma (either hemorrhaging or swim bladder distention), but only 32% of fish had two or more indicators and were thus deemed to have severe barotrauma. When telemetered fish were released at a common site, we determined that fish with negligible signs of barotrauma evacuated the release site more rapidly than fish with severe barotrauma did. Some fish with barotrauma floundered at the surface when released, and one of these fish was subsequently hit and killed by a boat. At the end of the monitoring period, 20% of fish with severe barotrauma had died; two additional individuals (20%) that were still at the release site were moribund (failed to respond to diver stimuli). Conversely, we failed to observe any mortality in fish with negligible signs of barotrauma. All tournament fish had elevated levels of blood glucose and lactate. However, stress indices were higher in fish with barotrauma and tended to be highest among fish with barotrauma that died after release. This study revealed that the incidence of barotrauma in tournaments can be high; moreover, outside of a laboratory environment, a significant proportion of fish with severe barotrauma may die after release. Additional research is needed to determine the seasonal variation in incidence and consequences of barotrauma as well as the effectiveness of different depressurization techniques in the field that could be used during fishing tournaments.
This study examines the physiological impacts of live-release angling tournament practices on walleyes Sander vitreus (formerly Stizostedion vitreum). Blood and white muscle samples were taken from walleyes following the weigh-in at several live-release angling tournaments in southern Ontario. The tournament walleyes had significantly elevated plasma cortisol levels in comparison with those of the control walleyes, indicating that tournament practices elicit a significant stress response in the tournament fish. Increased creatine phosphokinase and lactate dehydrogenase activities revealed that walleyes experience a moderate degree of cellular damage during live-release angling tournaments. In contrast to recent research with largemouth bass Micropterus salmoides, the tournament walleyes showed evidence of plasma ion loss. The tournament walleyes also experienced dramatic reductions in white muscle energy stores (phosphocreatine, ATP, and glycogen) and corresponding increases in plasma and white muscle lactate levels when compared with those of the control fish. These metabolic changes were similar in magnitude to the changes previously observed in largemouth bass following tournaments and suggest that current tournament procedures may commonly cause relatively large bouts of anaerobic metabolism in fish.
We evaluated the effect of barotrauma on the behavior of nine species of Pacific rockfish Sebastes spp. after hook-and-line capture and release using a video-equipped underwater release cage. Sampling was conducted across a range of bottom depths (12–194 m), mostly where barotrauma resulting from an expanded swim bladder and gaseous release of dissolved blood gases would be expected. Behavioral impairment from barotrauma was depth related but highly species specific. Increased depth of capture was associated with lower behavioral scores for black rockfish S. melanops, blue rockfish S. mystinus, and yelloweye rockfish S. ruberrimus, but not for canary rockfish S. pinniger. Behaviorally impaired fish showed a decreased ability to maintain vertical orientation and were slower in exiting the release cage. Species differed in the degree of behavioral impairment resulting from barotrauma and in how rapidly behavioral impairment increased with depth of capture. When captured at depths between 40 and 99 m, blue rockfish showed the most serious behavioral impairment, 8 of 18 (44%) failing to swim away at the time of release and simply drifting off in a sideways or upside-down posture. In the same depth range all of the other species sampled showed only moderate behavioral impairment, which is indicative of some potential for survival after discard by the fishery. Surface observations of the external signs of barotrauma were variable among species and were poor indicators of which species would show behavioral impairment upon release at depth. Within individual species, however, the external signs of barotrauma were associated with an increased probability of behavioral impairment at time of release.
The commercial and recreational harvests of red snapper Lutjanus campechanus in the Gulf of Mexico have declined over the past five decades, prompting strict regulations. Release mortality associated with catastrophic decompression (CD) is a possible cause for the continuing decline, although to date no physiological data exist to support this assumption. Using a flow-through high-pressure chamber, subadult red snapper were acclimated to 101.2, 405.3, 608.0, and 1,215.9 kPa, simulating depths typical of their distribution (as deep as 200 m), and then decompressed at a rate of 10.1 kPa/s. Lateral and dorsal X-ray imaging in combination with necropsy showed that swim bladders expanded in a predictable manner. Ventral expansion into the caudal body cavity space occurred at lower pressures, whereas expansion into the cranial portion of the body cavity occurred at the highest pressure. Expansion patterns resulted in over 70 different overexpansion injuries, the most severe being to vital organs. Our results suggest a specific suite of clearly identifiable injuries associated with CD that increase in number and severity as retrieval depth increases. A more thorough understanding of catastrophic decompression syndrome will provide insight into the declining fishery and aid in developing effective physiology-based management strategies.
We conducted a series of experiments to assess the real-time physiological and behavioral responses of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu to different angling related stressors and then monitored their recovery using both cardiac output devices and locomotory activity telemetry. We also review our current understanding of the effects of catch-and-release angling on black bass and provide direction for future research. Collectively our data suggest that all angling elicits a stress response, however, the magnitude of this response is determined by the degree of exhaustion and varies with water temperature. Our results also suggest that air exposure, especially following exhaustive exercise, places an additional stress on fish that increases the time needed for recovery and likely the probability of death. Simulated tournament conditions revealed that metabolic rates of captured fish increase with live-well densities greater than one individual, placing a greater demand on live-well oxygen conditions. The repeated handling of fish during tournament angling, including culling, the addition of fish or other live-well disturbances, and the final tournament weigh-in, which adds an additional several minutes of air exposure, further adds to already heightened stress levels. When these cumulative stressors do not result in death, the resultant energetic disruptions clearly have negative impacts not only on the short term health and condition of the fish, but also most likely on its biological fitness, i.e., its lifetime reproductive success. We also show that following angling, nest-guarding male bass face a reduction in their locomotory activity that may reduce their ability to successfully defend the nest. Although most concerns about catch-and-release angling occur at the population and community level, our assessment of various angling, handling and retention practices identifies ways to minimize the effects of angling upon individual fish, and to ensure that these effects do not manifest themselves as problems at the population level.
Catch-and-release recreational angling has become very popular as a conservation strategy and as a fisheries management tool for a diverse array of fishes. Implicit in catch-and-release angling strategies is the assumption that fish experience low mortality and minimal sub-lethal effects. Despite the importance of this premise, research on this topic has focused on several popular North American sportfish, with negligible efforts directed towards understanding catch-and-release angling effects on alternative fish species. Here, we summarise the existing literature to develop five general trends that could be adopted for species for which no data are currently available: (1) minimise angling duration, (2) minimise air exposure, (3) avoid angling during extremes in water temperature, (4) use barbless hooks and artificial lures/flies, and (5) refrain from angling fish during the reproductive period. These generalities provide some level of protection to all species, but do have limitations. Therefore, we argue that a goal of conservation science and fisheries management should be the creation of species-specific guidelines for catch-and-release. These guidelines would take into account the inter-specific diversity of fishes and variation in fishing techniques. As recreational angling continues to grow in popularity, expanding to many developing countries, and targeting alternative species, it is important that reasonable data appropriate for specific fish and fisheries are available. The sustainable use and conservation of recreational fishery resources will depend upon the development and dissemination of effective catch-and-release angling strategies based upon sound science to stakeholders around the world.
An evaluation of the hand-held portable Lactate Pro Analyser (KDK) was undertaken to assess its accuracy, reliability and versatility. Capillary blood samples were drawn from elite athletes in both laboratory and field settings and analysed in parallel. Accuracy was determined in relation to three other lactate analysers: (1) the ABL 700 Series Acid-Base analyser (n = 172 cases), (2) the Accusport Lactate Meter (n = 118 cases), and (3) the YSI 2300 Stat lactate analyser (n = 22 cases). The level of agreement was determined over the range of 1-18 mM. The repeatability of results between two different Lactate Pro analysers was also determined over the same range. Versatility was assessed in the field, where the Lactate Pro was used with elite athletes under a range of outdoor and indoor testing conditions. The correlations between the Lactate Pro and the ABL 700 Series Acid-Base analyser, YSI 2300 and Accusport were r = 0.98, r = 0.99, r = 0.97. The correlation between the two Lactate Pro analysers on the same sample (n = 96 cases) was r = 0.99. The level of agreement between the Lactate Pro and other analysers was generally less than +/- 2.0 mM over the physiological range of 1.0-18.0 mM (range of mean difference: -0.06 mM to 0.52 mM). The Lactate Pro was easy to operate and successfully completed the sample analysis in 100% of the tests performed. In summary, the Lactate Pro is accurate, reliable and exhibits a high degree of agreement with other lactate analysers.
A survey of competitive fishing activities in Canadian and U. S. jurisdictions was conducted during the summer-autumn of 2000 and the winter of 2001. Responses to a survey involving 10 questions were received from all 62 state, provincial, and territorial agencies contacted. Respondents reported 19,371 events and we estimate that over 25,000 competitive fishing events were held in 2000. Several social and biological issues associated with competitive fishing activities were reported. Social issues included congestion at access points, safety concerns, and conflicts with non-tournament anglers. Biological issues included increased fishing pressure, initial and delayed mortality, impacts of fish relocation, and the potential transfer of exotic species. There has been an increase in the development of policies and regulations associated with competitive fishing since the last survey was conducted in 1989 and it appears that more are being planned for the future. Approximately one-half of all North American jurisdictions now have a requirement to obtain a permit for an organized competitive fishing event. Research is needed to address potential impacts and to develop best management practices for competitive fishing activities.
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.
We found no evidence that deflating the expanded swim bladder of burbot Lota lota affected survival. In a mark–recapture study of the species in Green Bay, Lake Michigan, many burbot caught from depths greater than 10 m floated at the surface when tagged and released because of expanded swim bladders. We deflated the swim bladders by forcing a hollow needle through the body wall to puncture the expanded organ, and we conducted two experiments to assess the effect of our procedures on survival. In one experiment 103 burbot were tagged and deflated and then held in nets on the bottom; 99% were alive after 1–8 d (mean, 4 d). In another experiment 316 burbot were tagged, deflated, and released at the surface, and 337 control burbot were tagged, not deflated, but forced to the bottom and released in a weighted net with an open bottom. Most of these fish that were recaptured were at large more than 5 months, and returns did not differ between the two groups; 6.3% of the deflated fish were recaptured compared to 5.9% of the controls. Recaptures of tagged and deflated burbot that were not part of these experiments indicated that swim bladder healing began within the first week of release and was complete in 8 weeks.
Rapid depressurization oflargemouth bass Micropterus salmoides caught from deep water can result in expansion of the gas bladder. Largemouth bass released in such condition are unable to submerge and are subject to injury and predation. I compared angler returns in three California reservoirs for three groups of largemouth bass caught by angling: 76 fish with expanded gas bladders that were deflated by puncturing prior to release, 49 that did not demonstrate any gas bladder expansion but were punctured prior to release, and 159 that did not demonstrate any gas bladder expansion and were not punctured. Returns did not differ between punctured and control groups, suggesting that deflation of largemouth bass with expanded gas bladders is not harmful and can improve survival of released fish. Largemouth bass Micropterus salmoides that have acclimated to deep water and that are caught there by anglers are subjected to depressurization as they are brought to the surface, My observations indicate that most largemouth bass can resubmerge if released immediately. However, if retained in a live well for later release, gas bladder distention makes it impossible for the fish to resubmerge, and the fish will be subject to injury and predation.
Survival of red snapper Lutjanus campechanus captured by hook and line and then released was evaluated by two methodologies: release into cages and surface release, Fish captured at a depth of 50 m off the northeastern Texas coast were placed in cages, lowered to a depth of 35 m, and monitored at irregular intervals by scuba divers for 10–15 d. Sixty-four percent of caged red snapper survived. There was no significant difference in survival due to size (<30 cm versus ≥ 30 cm fork length; P = 0.59, N = 55) or to gas bladder eversion from the oral cavity (P = 0. 13, N = 45). No predation on red snapper released at the surface was observed. Survival rates were 99%, 90%, and 56% for fish captured at depths of 21–24 m, 27–30 m, and 37–40 m, respectively. Survival rates varied significantly with depth (P = 0.00, N = 232), suggesting an inverse relationship between survival and capture depth.
Artificial swim bladder deflation was examined as a technique to increase postrelease survival of largemouth bass Micropterus salmoides caught from deep water. Depressurization was simulated with a hyperbaric chamber. Largemouth bass showed clinical depressurization signs when depressurized from a simulated depth of 3.5 m and were unable to immediately submerge when depressurized from 8.4 m. When depressurized from a simulated depth of 10.5 m, largemouth bass experienced 0% mortality when subsequently held at 14°C but 78% mortality when held at 28°C. Survivors floated for more than 6 h, a response that could expose them to higher water temperatures in stratified lakes and to increased predation, illegal harvest, and injury. Depressurized largemouth bass that had their swim bladders deflated by being punctured with a hypodermic needle were able to submerge and experienced no mortality when transferred to 14°C or 28°C. The punctured swim bladders were functional immediately. Growth over 4 weeks did not differ significantly (P > 0.05) between largemouth bass with or without artificially deflated swim bladders, and no deaths occurred over this period. We recommend artificial swim bladder deflation for largemouth bass showing depressurization signs and caught from depths greater than 6 m.
Overinflation of the gas bladder following rapid depressurization is relatively common in fishes caught in deep water and brought to the surface. Currently, the most commonly used method to reduce mortality caused by overinflation is to puncture the gas bladder with a hypodermic needle. Although the method is widely used, few studies have been conducted to determine its effectiveness. We conducted a series of experiments on yellow perch Perca flavescens collected at 10 and 15 m depths in Lake Michigan. Fish were either measured for length (control), measured and tagged, or measured, tagged, and punctured. The fish were then taken to an enclosed hatchery facility. Fish brought to the surface in stages (decompressed) had higher survival than nondecompressed fish; this effect was greater for fish caught at 10 than 15 m. Unpunctured fish floated for up to 72 h before regaining neutral buoyancy; less than 2% of the punctured fish floated on the first day. Puncturing the swim bladder had a significant, positive effect on 3-d survival. Tag returns from fish released after the experiment indicated that puncturing did not decrease longterm survival. This study demonstrates the effectiveness of puncturing the gas bladder in reducing direct mortality caused by bladder overinflation, and indirect mortality of the stricken fish which are vulnerable to predation and adverse environmental conditions at the surface. Decompression positively affected survival and, because of its ease of use, warrants further investigation.
The effects of induced, rapid depressurization upon largemouth bass (Micropterus salmoides), simulating conditions common to deep-water angling, were examined. Depths of 0.0, 9.1, 18.3, and 27.4 m were simulated in a large hyperbaric chamber. Statistical analyses indicated that significant mortality occurred when fish were depressurized from simulated depths of 18.3 and 27.4 m. Individuals depressurized from all depths experienced bloating and some external hemorrhaging, while those depressurized from simulated depths of 18.3 and 27.4 m experienced severe internal hemorrhaging and formation of gas bubbles in their blood. If largemouth bass are caught at depths greater than 18.3 m, at least 40% mortality will result from depressurization alone. Therefore, anglers may have to refrain from fishing at these depths if they intend to release their catch.
Organized competitive sportfishing has been a growing use of fishery resources for at least the last 20 years. We conducted a survey of fishery agencies in Canada, the United States, District of Columbia, Puerto Rico, and U.S. Virgin Islands to estimate the numbers and types of competitive fishing events in inland and marine waters and to determine fishery agency perceptions of the benefits and problems associated with these events. Based on survey responses, there were 20,697 competitive fishing events annually. Adjusting for agencies that did not provide estimates and incomplete reporting, we estimated that there were at least 31,000 competitive fishing events annually. Most competitive fishing events were for black bass in inland waters and billfish in marine waters, but events targeted many species of fish. In inland waters, events for species other than black bass appear to be increasing. Prevalent problems of competitive fishing perceived by fishery management agencies were stimulation and concentration of fishing effort, conflicts among user groups, and impeded access. Prevalent benefits of competitive fishing were economical acquisition of catch and biological data, promotion of recreational fishing, and communication between agencies and anglers. Our survey indicated the need for accurate (rather than estimated) and current data about competitive fishing and further investigations of sociological aspects, economic values, and biological impacts of competitive fishing events.
A survey of competitive fishing activities in Canadian and U. S. jurisdictions was conducted during the summer-autumn of 2000 and the winter of 2001. Responses to a survey involving 10 questions were received from all 62 state, provincial, and territorial agencies contacted. Respondents reported 19,371 events and we estimate that over 25,000 competitive fishing events were held in 2000. Several social and biological issues associated with competitive fishing activities were reported. Social issues included congestion at access points, safety concerns, and conflicts with non-tournament anglers. Biological issues included increased fishing pressure, initial and delayed mortality, impacts of fish relocation, and the potential transfer of exotic species. There has been an increase in the development of policies and regulations associated with competitive fishing since the last survey was conducted in 1989 and it appears that more are being planned for the future. Approximately one-half of all North American jurisdictions now have a requirement to obtain a permit for an organized competitive fishing event. Research is needed to address potential impacts and to develop best management practices for competitive fishing activities.
— Responses of rainbow trout, Oncorhynchus mykiss, to handling and confinement stress were used to validate the efficacy of portable instruments for measuring blood glucose and lactate, and plasma protein. Glucose and lactate increased with time and showed good linear correlation with time after disturbance. The Advantage blood glucose and Accusport™ lactate meters were similarly correlated, except that values were consistently lower than those obtained by established laboratory techniques. Refractometry gave higher plasma protein values than results from biuret reagent but with excellent correlation. These findings indicate a potential role for portable instruments in field and hatchery locations where relative rather than absolute values may be used to evaluate responses to stressors.
Turning, pectoral fin and caudal fin rates and time spent on the nest of male rock bass Ambloplites rupestris, engaged in parental care, were not affected after the attachment of external radio transmitters. Reproductive success was similar between treatment and control fish. Micro external radio transmitters can be used on small fishes for studying parental care duration and post-care movement without altering their behaviour.
Abstract This paper summarises recent peer-reviewed literature addressing the effects of catch-and-release angling on black bass, Micropterus spp., to facilitate management and conservation of these fish. Traditionally, the effects of catch and release have been evaluated by measuring mortality. Many recent studies have measured sublethal effects on physiology and behaviour. There is also greater emphasis on adding more realism to sublethal catch-and-release experiments through angler involvement in research activities and by conducting studies in the field rather than in laboratory environments. Owing to these advances, there have been a number of recent findings, which are summarised here, related to air exposure, gear (e.g. circle hooks) and the weigh-in procedure that are particularly relevant to black bass anglers, tournament organisers and fishery managers. Additional research is particularly needed for: (1) population-level effects of angling for nesting fish; (2) population-level effects of tournament-associated mortality; (3) effectiveness of livewell additives for enhancing survival; (4) consequences of fish displacement in competitive events; (5) effects of weigh-in procedures and other organisational issues on fish condition and survival; and (6) reducing barotrauma.
Abstract The practice of catch and release (CR) as a fisheries management tool to reduce fishing mortality is widely applied in both freshwater and marine fisheries, whether from shifts in angler attitudes related to harvest or from the increasing use of harvest restrictions such as closed seasons or length limits. This approach assumes that for CR fishing policies to benefit the stock, CR will result in much lower mortality than would otherwise occur. There are many challenges in the design of CR studies to assess mortality, and in many practical settings it is difficult to obtain accurate and precise estimates. The focus of this article is on the design and quantitative aspects of estimating CR mortality, the need for a comprehensive approach that explicitly states all components of CR mortality, and the assumptions behind these methods. A general conceptual model for CR mortality that is applicable to containment and tagging-based studies with a slight modification is presented. This article reviews the design and analysis of containment and tagging studies to estimate CR mortality over both the short and long term and then compares these two approaches. Additionally, the potential population-level impacts of CR mortality are discussed. A recurring theme is the difficulty of designing studies to estimate CR mortality comprehensively and the need for additional research into both statistical model development and field study design.
Tagging experiments on grey cod
- C R Forrester
Forrester, C.R., 1954. Tagging experiments on grey cod. Fisheries Research Board of Canada Pacific Coast Stations Progress Report 99, 28–29.
Measurements of stressed states in the field
- Morgan
Morgan, J.D., Iwama, G.K., 1997. Measurements of stressed states in the field. Society for Experimental Biology Seminar Series 62, 247–268.