Observations of Mudpuppy (Necturus maculosus) bycatch in a recreational ice fishery in northern Ontario

Bycatch in fisheries is a well-explored topic, although less so in recreational fisheries. We encountered frequent bycatch of Mudpuppy (Necturus maculosus), a neotenic aquatic salamander that is active in winter, in passively baited ice-fishing gear targetting teleost fishes. We noted hook location in Mudpuppies captured by two hook types: J-hooks and circle hooks. Our prediction was that circle hooks would reduce the frequency of deep hooking of Mudpuppies, which is often cited as an important predictor of post-release mortality in fishes. We found no difference in the frequency of deep hooking of Mudpuppies captured by circle or J-hooks, although, in a subset of Mudpuppies (n = 13) held for 24 h after capture, one death occurred (8%). Further research may be necessary to determine whether deeply hooked Mudpuppies can pass or shed hooks and survive beyond the 24-h period we monitored. However, our findings suggest that anglers and managers should consider refinements to handling practices for Mudpuppies captured as bycatch, because they are likely to survive if handled cautiously. These results, which are among the first describing non-fish bycatch in recreational fisheries, call for managers and anglers who encounter Mudpuppies during recreational fishing to seek more information and educational opportunities to improve the fate of this important component of temperate freshwater ecosystems and ecological indicator species that is incidentally captured by ice fishing

Baseline activity and shoal type determine antipredator behaviors in bluegill from a southern Ontario lake

Abstract: Shoaling is an evolved behavior in fishes that has several adaptive advantages, including allowing individuals to avoid predation through risk dilution. However, factors such as size disparity and the presence of heterospecifics may influence the behavior of individual fish within shoals following exposure to elevated predation risk. Using bluegill Lepomis macrochirus as a model species, we measured changes in area use, shoaling index, and movement of a focal individual in isolation, in single-species shoals with two conspecifics, or in mixed-species shoals with two congeneric pumpkinseed L. gibbosus. The experimental shoals were exposed to one of three chemical cues selected to present graded levels of risk: lakewater controls (lowest risk), Northern pike Esox lucius predator odor (kairomones; intermediate risk), or conspecific chemical alarm cues (highest risk). Within the individual bluegill, we found that the multivariate response of area use and post-stimulus activity (line crosses) of the focal fish was significantly influenced by pre-stimulus activity, but not by cue type or fish size. As univariate responses, post-stimulus activity varied positively with pre-stimulus activity. Post-stimulus activity was greater in single-species shoals compared to mixed-species shoals, and again varied positively with pre-stimulus activity. Contrary to predictions, bluegill did not demonstrate graded antipredator responses to the chemical cues. Our findings suggest that prey fish may alter their risk-aversive behaviors in response to chemical stimuli based on shoal composition and provide further insight into the role of intra-prey guild interactions in response to predators in co-occurring prey species. Significance statement: When faced with predation, individuals in groups may experience lower levels of risk than solitary individuals. Using bluegill as a model organism, we examined how antipredator behaviors, in response to chemical cues indicating different levels of risk, varied between focal individuals as singletons and in single- and mixed-species shoals. Contrary to our prediction of graded stepwise responses indicative of differing levels of risk posed by the cues, we found that individuals with greater baseline activity levels demonstrated weaker antipredator responses independent of cue type, while fish in single-species shoals had higher post-stimulus activity levels than fish in mixed-species shoals. Our results suggest that studies examining changes in antipredator and shoaling be

Fido, Fluffy, and wildlife conservation: The environmental consequences of domesticated animals

Humans have created a strong relationship with cats and dogs by domesticating them. Whether owned by a human or living feral, modern domestic cats and dogs interact extensively with people and the environment. The negative interactions between these domesticated animals and wildlife have been discussed in several reviews, but few reports have provided an overview of both the positive and negative impacts these domesticated animals have on wildlife conservation. Here, we describe the diverse issues associated with domestic cats and dogs and wildlife including predation, competition, pathogen transmission, hybridization, behavioural modification, harvest of wild animals for pet food, and creation of human-wildlife conflict. We then discuss their role in supporting conservation efforts (e.g., use in species identification and tracking, biological control), and shaping our social values towards animals and appreciation for nature. Finally, we suggest necessary steps to harmonize our relationship with cats and dogs and the conservation of wildlife. For owned animals, there is potential for pet owners to support conservation efforts through a pet tax' adopted by veterinary clinics and pet stores to be used for wildlife conservation. Moreover, information regarding the impacts of these animals on wildlife and potential solutions (e.g., voluntarily keeping cats and dogs inside or use of "pet curfews", use of bells to alert wildlife to cats) should be made available to owners who are most likely to have an influence on the behaviour of their companion animal

Consequences of winter air exposure on walleye (Sander vitreus) physiology and impairment following a simulated ice-angling event

Length-based harvest restriction is common in fisheries management and can result in a substantial number of fish being released after capture. Science on live release confirms that the practice allows individuals to return to the population and reproduce; however, little is known about how handling practices influence mortality or the sub-lethal physiological alterations in fish that are released during the winter. In this study, walleye (Sander vitreus; Mitchill 1818) were angled through the ice in Lake Nipissing, Ontario to evaluate the contribution of air exposure to the reflex impairment, post-release mortality, and the stress response of fish in the winter. Following 24 h holding, fish were exposed to a simulated angling event and exposed to air or snow across a range of exposure durations. Fish were non-l

Quantitative assessment of fish passage efficiency at a vertical-slot fishway on the Daduhe River in Southwest China

Fish passage facilities are constructed to enable fish to pass anthropogenic barriers such as dams though their efficiency varies across species and location. There are a number of studies that assess the efficiency of fish passage facilities, yet rarely have such assessments been conducted in Asia. We conducted one of the first quantitative assessments of the efficiency of a vertical-slot fishway in Asia on the Daduhe River in Southwest China. Quantitative assessment of fish passage efficiency was conducted using a combination of methods, including fish sampling, video recordings and a Passive Integrated Transponder (PIT) system for tracking individually-tagged fish (N = 69 of 6 species). Fish sampling revealed 40 species assembled downstream of the dam. Fish captured closer to the fishway tended to be larger than fish caught more distant from the fishway. Half of the fish species observed downstream of the fishway were also observed at the entrance to the fishway (i.e. 153 individuals across 20 species). Video records revealed that overall passage rates were 71.2% based on the number of fish observed at the exit of the viewing chamber relative to that observed passing the entrance viewing chamber. Most fish passed the fishway at night with peak passage occurring in June. PIT technology results revealed that passage efficiency among the six tagged species ranged from 0% to 60% (four species successfully ascended the fishway). Transit time from the fishway entrance to exit was variable both among and within species that successfully ascended the fishway (i.e. 17.9–20.3 h for Schizothorax davidi, 6.4–88.8 h for Schizothorax preuanti, 46.4 h for Silurus meridionalis, 22.1–53.9 h Semilabeo prochilus). Fishway performance varied by species such that there is evidence that the fishway may be useful for maintaining river connectivity for some species. However, passage was often restricted during periods when there was sufficient flow in the fishway. Additional research is needed to put these findings in an ecological context given the overall low number of fish that passed the dam

Biologging in combination with biotelemetry reveals behavior of atlantic salmon following exposure to capture and handling stressors

We investigated the response of Atlantic salmon (Salmo salar) to capture and handling stressors by analyzing fine-scale locomoto

The nexus of fun and nutrition: Recreational fishing is also about food

Recreational fishing is a popular activity in aquatic ecosystems around the globe using a variety of gears including rod and line and to a lesser extent handlines, spears, bow and arrow, traps and nets. Similar to the propensity to engage in voluntary catch-and-release, the propensity to harvest fishes strongly varies among cultures, locations, species and fisheries. There is a misconception that because recreational fishing happens during non-work (i.e. leisure) time, the nutritional motivation is negligible; therefore, the role of recreational fishing in supporting nutrition (and thus food security) at regional, national or global scales is underappreciated. We consider the factors that influence whether fish will be harvested or released by examining the motives that underlie recreational fishing. Next, we provide an overview of the magnitude and role of recreational fishing harvest in supporting nutrition using regional case-studies. Then, we address issues such as contaminants and parasites that constrain the ability of fish harvested by recreational fishers to be consumed. Although recreational fishing is foremost a leisure activity, the harvest of fish for personal consumption by recreational fishers has contributed and will continue to contribute to human nutrition by providing an accessible, affordable and generally highly sustainable food source, notwithstanding concerns about food safety and possibly overfishing. Attempts to better quantify the role of fish harvested by recreational fishers and the relative contribution to overall food security and personal nutrition will provide resource managers and policymakers the information needed to guide management activities and policy development

Comparison of the behavioral consequences and recovery patterns of largemouth bass exposed to MS-222 or electrosedation

Fish are commonly sedated to render them immobile and thus easier to handle for research, veterinary, and aquaculture practices. Since sedation itself imposes a significant challenge on the targeted fish, the selection of sedation methods that minimize physiological and behavioral disturbance and recovery time is essential. Two popular sedation methods include the chemical tricaine methanesulfonate (MS-222) and electrosedation. Although many studies have already investigated the physiological consequences of these methods, there is limited research examining the latent behavioral effects on fish. Using Largemouth Bass Micropterus salmoides as a model species, we compared the postsedation behaviors of fish that were sedated with either MS-222 or electrosedation to those of a control group exposed to the same handling protocol. Immediately after sedation, fish exposed to either treatment demonstrated lower reflex scores than the control group. Time to resume regular ventilation did not differ between chemically sedated and electrosedated fish; however, electrosedated fish regained equilibrium faster (mean ± SE = 154 ± 20 s) than fish that were exposed to MS-222 (264 ± 30 s). Locomotor activity and swimming performance were assessed at 5-, 30-, or 60-min intervals, beginning after individuals had recovered from sedation sufficiently to regain equilibrium. For all postsedation intervals, locomotor activity was two times greater in the electrosedated group than in the control and MS-222 groups. Other behavioral measures (refuge emergence time, activity level, and flight initiation distance) and swimming performance did not differ at 5, 30, or 60 min postrecovery for any of the treatment groups. Our results indicate that while both chemical and electrical sedation methods result in impairment (i.e., sedation) immediately after treatment, these behavioral effects do not persist beyond 5 min postrecovery, and the two methods have similar impacts on Largemouth Bass. However, we caution that these results cannot be extrapolated to other fish species without further study

Influence of hook type and live bait on the hooking performance of inline spinners in the context of catch-and-release brook trout Salvelinus fontinalis fishing in lakes

The objective of catch-and-release angling is for the fish to survive with minimal fitness consequences. However, fish survival can be compromised by a number of factors, especially anatomical hooking location. To evaluate whether hook type or bait influence hooking outcomes, we tested different combinations of hook (treble or single siwash hooks) and bait (hook tipped with worm or no worm) while angling for brook trout (Salvelinus fontinalis) with inline spinner-style fishing lures. The study was conducted at spring water temperatures (∼20 °C) in small lakes stocked with trout in southwestern Quebec, Canada. Incidences of hooking in the interior of the mouth (i.e. internal hooking) were uncommon (19%), did not differ significantly between hook types or bait treatments, and occurred independently of fish size. Reflex impairments after hook removal were not related to hook or bait treatment. Short-term mortality was quantified with 24 h holding in net pens and was determined to be infrequent for all treatment groups (treble/worm: 6%; treble/no worm: 5%; single/worm: 2%; single/no worm: 0%). Although no fish were hooked in the gills, esophagus, stomach, odds of mortality increased by 14.21 when fish were hooked internally, which is consistent with the position that hook placement is an important predictor of the fate of fish released by anglers. However, our finding that neither hook nor bait type significantly increased the odds of internal hooking, bleeding, reflex impairment, or mortality in this study suggests that restrictions imposed on the use of baited lures or certain hook types attached to lures when fishing may have little influence on short-term catch-and-release mortality of brook trout at these temperatures