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The human dimension is one major source of uncertainty in the management of social-ecological systems such as fisheries. Agent-based models (ABMs) can help to reduce these uncertainties by making it possible to model and simulate human behavior. To understand how ABMs can be applied in fisheries science, a classification scheme was developed based on reviews in other social-ecological domains, theoretical frameworks, and documentation standards. This classification scheme was subsequently used to review agent-based simulation studies that modeled human decision-making in a fisheries context to identify trends and knowledge gaps. Applying the classification scheme revealed that the existing fisheries-related ABMs employ a variety of decision theories, policies, social interactions, agent memories, and data sources, and revealed a wide potential for applications of ABMs to a broad range of research questions and management recommendations. Nevertheless, it turned out that it is, so far, virtually unexplored how environmental factors influence fishing decisions or how social norms and learning influence fishing behavior. It also became clear that the documentation and provenance information of ABMs need to be improved – e.g., by applying standardized documentation procedures, such as ODD + D and TRACE – to enhance the credibility, transparency, and reusability of ABMs in fisheries science.

Marine recreational fishing is popular in Norway, but current estimates of the catches by resident and tourist anglers are lacking due to several challenges, in particular Norway’s long and intricate coastline with no defined access points and the large tourist fishery. To test methods for long-term monitoring of boat-based marine recreational anglers, estimate their catches, and characterize the fishery, we conducted a roving creel survey based on a novel spatial sampling frame and a survey of tourist fishing businesses in Troms and Hordaland County. These surveys showed that cod (Gadus morhua) and saithe (Pollachius virens) dominated the catches in Troms, while mackerel (Scomber scombrus) and saithe dominated the catches in Hordaland. The estimated total annual harvest of cod by all marine recreational anglers was 2 160 tonnes (relative standard error, or RSE 44%) in Troms and 73 tonnes (RSE 29%) in Hordaland, of which ∼40% (in weight) were landed in registered tourist fishing businesses, based on data from the tourist fishing survey. The results indicate that recreational anglers in Hordaland harvest more cod in coastal waters than commercial fishers. This study provides information for developing marine recreational fisheries monitoring in challenging survey situations to support science-based fisheries management.

Globally, marine recreational fishing is a popular activity that contributes substantially to fishing mortality for some stocks and therefore should be considered in stock assessments and fisheries management. Using the example of the German western Baltic Sea recreational cod fishery, this study examines the effects of the first-time introduction of a bag limit on a previously largely unregulated marine recreational fishery. Furthermore, the study simulates and compares effects of different bag limits, seasonal closures, minimum length, and harvest slot limits to inform scientists, stakeholders, and managers about alternative management strategies and their potential effects on the fishery. After the first-time introduction of the bag limit, recreational removals decreased more than expected and the fishing participation slightly declined. The simulations showed that management measures adapted to the fishing methods reduced recreational removals but with different effects on cod length distributions and angler welfare. A combination of a high bag limit, seasonal closure and size/slot limits were most suitable for limiting cod removals with minimal impacts on angler welfare. This study demonstrates that recreational fisheries management measures need to be evaluated considering fishing methods and angler preferences before their implementation to avoid unexpected biological, social, and economic consequences.

Sea trout (anadromous brown trout, Salmo trutta L.) is a popular recreational angling target species in the Baltic Sea region and beyond. Across countries, a substantial part of angled sea trout is released after capture either due to management regulations or due to voluntary decisions by the anglers. However, information about post-release impacts of catch and release (C&R) on survival and growth in saline waters is largely missing. We used a flow-through seawater raceway (4–10 °C) to investigate impacts on survival and growth of angled and released sea trout (< 40 cm) up to 29 days post release. Bleeding was common among angled sea trout, but differed between angling treatments, i.e., lure fishing with treble hook (size 4), lure fishing with single hook (size 1/0) and fly fishing with single hook (size 12). However, no mortality and no significant differences in growth were found after a 26–29 days monitoring period among a control group and the three treatment groups, but a small subset (6%) of the angled fish caught on lure had unhealed/infected hooking wounds at the end of the experiment. The results infer that adverse effects of C&R on coastal sea trout due to high post-release mortality or reduced growth can be limited and may not pose a significant problem for sea trout stocks. Nevertheless, further studies are required to corroborate these results under more natural field conditions and at higher water temperatures. In addition, further studies on long-term sublethal impacts of C&R on sea trout are needed.

Recreational fishing is increasingly included in fish stock assessments globally. Nonetheless, the extent and precision of recreational fisheries data are often limited. Common methods to collect those data are on-site and off-site surveys, both of which are prone to specific biases, whose magnitude is widely unknown. The present study compares data from an on-site access point intercept and a simultaneously conducted off-site diary survey, separately targeting charter boat, boat, and shore anglers in the German Baltic Sea recreational cod fishery to identify specific biases in the data sets. The analyses revealed indications of avidity and recall bias that might influence catch and release estimates. Catch rates and release rates differed substantially between the angling platforms. The catch and release rates of diarists and on-site anglers were in a similar range for every platform, and reasonably precise with standard errors between 0.1 and 0.4 fish per angler and day. Recreational fishing monitoring approaches should include complementary on-site surveys from time to time to control for biases whereby the angling platform should be taken into account. The low explanatory power of commonly collected socio-demographic variables indicated that variables capturing the heterogeneity of angler behaviour should additionally be included in future surveys.

Sea trout (anadromous brown trout, Salmo trutta L.) is a popular target species for angling in Denmark and many other countries. In most regions, angling for sea trout is regulated by measures such as minimum landing sizes, bag limits or seasonal closures. This can lead to high catch and release (C&R) rates. However, information about angler behavior, C&R practices, hooking locations and level of injury and bleeding, as well as post-release impacts on survival and growth, is largely missing for this species. In this study, we used a citizen science approach to investigate C&R practices of Danish sea trout anglers and to explore drivers for hooking location and bleeding. During the study period from January 2016 to August 2021, 35,826 sea trout caught by angling were reported by users of the citizen science platform. Spin fishing was the most popular angling method (46 %), followed by fly fishing (35 %), bombarda fishing (19 %) and natural bait fishing (1 %). The results confirmed that C&R is a very widespread practice among Danish sea trout anglers, and ≥80 % of all sea trout captured are being released, the majority because they are below the minimum landing size. Twenty-five percent of the caught sea trout bled, and 2 % showed heavy bleeding. Bleeding was related to hooking location (deeply hooked fish bled the most) and to angling method (fly-caught sea trout bled less than fish caught on spin fishing gear), but the role of these two factors varied with fish length. When looking at fish above the legal minimum size, the share of bleeders among the released sea trout was significantly lower compared to harvested fish, suggesting that anglers were more prone to harvest fish that bled. Further studies on lethal and sublethal effects of C&R on coastal sea trout are needed, ultimately aiming to provide fishery managers and anglers with species- and fishery-specific best practice C&R guidelines.

Marine recreational fishing (MRF) is a popular activity that involves millions of people worldwide. While the impacts of recreational fishing on freshwater ecosystems received increasing attention ...

Smartphone applications (apps) that target recreational fishers are growing in abundance. These apps have the potential to provide data useful for management of recreational fisheries. We surveyed expert opinion in 20, mostly European, countries to assess the current and future status of app use in marine recreational fisheries. The survey revealed that a few countries already use app data to support existing data collection, and that this number is likely to increase within 5–10 years. The strongest barriers to use app data were a scarcity of useful apps and concern over data quality, especially biases due to the opt-in nature of app use. Experts generally agreed that apps were unlikely to be a “stand-alone” method, at least in the short term, but could be of immediate use as a novel approach to collect supporting data such as, fisheries-specific temporal and spatial distributions of fishing effort, and aspects of fisher behaviour. This survey highlighted the growing interest in app data among researchers and managers, but also the need for government agencies and other managers/researchers to coordinate their efforts with the support of survey statisticians to develop and assess apps in ways that will ensure standardisation, data quality, and utility.

European sea bass (Dicentrarchus labrax) is an important target species for recreational and commercial fisheries. In recent years, the spawning stock biomass has declined markedly in some areas, and strict management measures have been introduced. However, the development of appropriate stock assessment and fisheries management has been hampered by a lack of information on post-release mortality. This study investigated post-release mortality of sea bass captured with common recreational fishing gear under experimental conditions in an aquaculture facility over 10 d. Three experiments investigated: (i) the effects of different bait types; (ii) the impact of prolonged air exposure; and (iii) the impact of deep hooking on post-release mortality. By combining the experimental results with country-specific information on sea bass angling practices, estimates of post-release mortality are provided for the northern sea bass stock. No mortality was observed for sea bass captured on artificial baits. The use of natural baits resulted in a mortality of 13.9% (95% CI = 4.7–29.5%), which was associated with deep hooking, hooking injuries, and prolonged air exposure. The use of artificial baits and short air exposure (≤30 s) increased survival probability, whereas deep hooking resulted in 76.5% (95% CI = 50.0–93.2%) mortality. Depending on country-specific angling practices, post-release mortality estimates ranged from 2.8% to 9.1% (mean = 5.0%, 95% CI = 1.7–14.4%) for northern sea bass. Despite these relatively low mortality estimates, post-release mortality should be considered in stock assessments as its cumulative impact may be high. Moreover, post-release mortality can be reduced by implementing species-specific best practice guidelines.

Marine litter affects marine environments and ecosystem services worldwide. A substantial amount of the traceable marine litter originates from tourism and recreational activities. An important activity carried out in coastal areas is marine recreational fishing (MRF). Although the impacts of MRF on marine ecosystems has received increasing attention during recent years, the contribution of MRF to marine litter is widely unknown. Marine litter is caused by human activities and its avoidance requires an understanding of environmental behaviour. This study presents results obtained by a telephone survey aimed to assess the behaviour, motivations and attitudes of Baltic Sea anglers towards marine litter. The telephone survey identified three angler types primarily separated by the predominant motives regarding nature experience, catch orientation and challenge seeking. Regardless of their motivation, most anglers were concerned about marine litter, recognised their responsibility and were willing to contribute to litter avoidance and mitigation. The telephone survey was supplemented by face-to-face angler interviews during a stratified random access point intercept survey along the German Baltic coast to estimate the amount of lost fishing tackle based on anglers self-reports. According to the reports, the loss of fishing tackle was a rare event for individual anglers. Nonetheless, given a high number of Baltic Sea anglers and angling effort, local environmental impacts due to lost fishing tackle on marine environments cannot be excluded.

Fish are increasingly exposed to anthropogenic stressors from human developments and activities such as agriculture, urbanization, pollution and fishing. Lethal impacts of these stressors have been studied but the potential sublethal impacts, such as behavioural changes or reduced growth and reproduction, have often been overlooked. Unlike mortality, sublethal impacts are broad and difficult to quantify experimentally. As a result, sublethal impacts are often ignored in regulatory frameworks and management decisions. Building on established fish bioenergetic models we present a general method for using the population consequences of disturbance framework (PCoD) to investigate how stressors influence ecologically-relevant life processes of fish. We partition impact into the initial energetic cost of attempts to escape from the stressor, followed by the energetic impacts of any injury or behavioural change, and their consequent effects on life processes. As a case study, we assess the sublethal effects of catch and release angling for the European sea bass (Dicentrachus labrax, Moronidae), a popular target species for recreational fishers. The energy budget model described is not intended to replace existing experimental approaches but does provide a simple way to account for sublethal impacts in assessment of the impact of recreational fisheries and aid development of robust management approaches. There is potential to apply our energy budget approach to investigate a broad range of stressors and cumulative impacts for many fish species while also using individual-based models to estimate population level impacts.

The marine recreational fishery (MRF) is a branch of coastal tourism with noticeable effects on fish stocks, coastal environments, and economies. Nevertheless, little research has been conducted on its spatio-temporal dimensions. This study extends the knowledge about marine angling tourism by investigating activity hot spots and travel distances of 8429 German Baltic Sea anglers using data obtained from an on-site survey which was conducted from 2015 to 2019. Fishing from shores, small boats, and charter vessels, the anglers targeted primarily Atlantic cod and to a lesser extent sea trout, salmon, and herring. Angling effort clustered along the coast primarily according to the available infrastructure and the spatial distribution of the target species. The medians of travel distances differed among the target species and decreased from salmon (261 km), cod (194 km), sea trout (63 km) to herring (44 km). The high percentage of non-resident anglers, most of whom travelled more than 200 km to the coast, suggested that particularly cod and salmonid anglers conducted multiple-day trips and contributed to local economies. The period 2016/17 was characterised by a severe decline of the western Baltic cod stock and the first-time implementation of harvest limitations. The number and travel distances of cod charter vessel anglers decreased after the implementation, whereas the numbers and travel distances of boat and shore anglers targeting cod remained constant despite overall decreasing catch rates. The delineation of areas where marine recreational fishing concentrates may help to define areas relevant for tourism development and destination branding and equally those that require a risk assessment to evaluate the potential extent and consequences of MRF on local environments. The travel distances underlined the heterogeneity of the MRF and may be used as tool to identify stakeholder groups, to estimate the species-specific attractiveness for resident and non-resident anglers, and to evaluate the outcome of management actions.

We used time series, diet studies and angler surveys to examine the potential for conflict in brackish lagoon fisheries of the southern Baltic Sea in Germany, specifically focusing on interactions among commercial and recreational fisheries as well as fisheries and cormorants (Phalacrocorax carbo sinensis). For the time period between 2011 and 2015, commercial fisheries were responsible for the largest total fish biomass extraction (5,300 t per year), followed by cormorants (2,394 t per year) and recreational fishers (966 t per year). Commercial fishing dominated the removals of most marine and diadromous fish, specifically herring (Clupea harengus), while cormorants dominated the biomass extraction of smaller-bodied coastal freshwater fish, specifically perch (Perca fluviatilis) and roach (Rutilus rutilus). Pike (Esox lucius) as large-bodied freshwater fish was the only species where recreational fisheries were responsible for the major fraction of the annual biomass extraction. A strong trophic overlap and hence a similar foraging niche was documented among commercial fishers and recreational anglers and among non-resident and resident anglers, indicating that the aversion expressed by anglers against commercial fisheries in a survey had an objective underpinning related to resource competition. By contrast, the foraging niches of cormorants and of both fishers and anglers differed strongly as evidenced by largely non-overlapping sets of species that were caught and removed by cormorants and by commercial as well as recreational fishers. However, for individual species of commercial and recreational interest, specifically perch, cormorants were responsible for a major fraction of total biomass extraction, suggesting that at the individual fish species level competition with fishers and anglers may still occur. In an angler survey, respondents expressed a preference for cormorant control, indicating the existence of conflict between fisheries and cormorants. We recommend that conflicts in the lagoon fisheries be proactively managed, e.g., through improved communication, zoning, predator control and outreach. Further research should clarify the population-level impacts of cormorants on target species of commercial and recreational fisheries as well as the relative impact of commercial and recreational fisheries on selected species of joint interest.

Atlantic cod (Gadus morhua) is an important recreational and commercial fisheries target species in the Northern hemisphere. Release rates are high in the recreational fishery due to regulatory and voluntary catch-and-release practice. Although post-release mortality of cod is relatively low, there is potential for further reductions. The most effective way to reduce post-release mortality is to minimize the catch of sublegal fish or non-target species and to reduce hooking injuries by using more selective fishing methods. This study investigated the influence of the lure/bait type on: (1) size of fish, (2) catch and harvest, (3) proportion of bycatch, (4) hooking location, and (5) injury (bleeding) in the western Baltic Sea recreational cod fishery. Data were collected via random onboard sampling of 35 charter vessel angling trips (778 anglers) and during two supplementary studies in the western Baltic Sea. Overall, the median total length was significantly higher for cod caught on artificial lures (39 cm) than for cod caught on natural bait (28 cm), leading to a 43% higher proportion of sublegal (

Norway has the highest participation rate in marine recreational fisheries (MRF) in Europe, and is popular among marine tourist anglers. Fishing licences are not required for marine recreational anglers, and the complex and long coastline makes on-site surveys a challenge. A novel approach for spatial sampling was developed and tested in on-site surveys, as part of a National study of MRF using multiple sampling frames including a telephone screening survey based on the national telephone directory. Field surveys were conducted in Troms and Hordaland Counties, and in the Oslofjord. We created spatial sampling frames of modified Voronoi polygons with continuous sea-surface area, with clusters of polygons as primary sampling units (PSUs). Interviews of intercepted anglers were obtained quarterly from a stratified sample of PSUs searched by boat. Many anglers interviewed in Troms (63%) and Hordaland (53%) were non-residents, of which 92 and 66% stayed in registered tourist fishing camps, respectively. Most anglers in the Oslofjord were residents, and in the inner Oslofjord, 63% of the resident anglers interviewed on-site were born outside Norway, which was not reflected in the telephone survey. Thus, if only off-site methods were used to map Norwegian MRF, this could lead to biased results in some regions.

Este artículo contiene 19 páginas, 7 tablas, 4 figuras., Marine recreational fishing (MRF) is a high-participation activity with large economic value and social benefits globally, and it impacts on some fish stocks. Although reporting MRF catches is a European Union legislative requirement, estimates are only available for some countries. Here, data on numbers of fishers, participation rates, days fished, expenditures, and catches of two widely targeted species were synthesized to provide European estimates of MRF and placed in the global context. Uncertainty assessment was not possible due to incomplete knowledge of error distributions; instead, a semi-quantitative bias assessment was made. There were an estimated 8.7 million European recreational sea fishers corresponding to a participation rate of 1.6%. An estimated 77.6 million days were fished, and expenditure was €5.9 billion annually. There were higher participation, numbers of fishers, days fished and expenditure in the Atlantic than the Mediterranean, but the Mediterranean estimates were generally less robust. Comparisons with other regions showed that European MRF participation rates and expenditure were in the mid-range, with higher participation in Oceania and the United States, higher expenditure in the United States, and lower participation and expenditure in South America and Africa. For both northern European sea bass (Dicentrarchus labrax, Moronidae) and western Baltic cod (Gadus morhua, Gadidae) stocks, MRF represented 27% of the total removals. This study highlights the importance of MRF and the need for bespoke, regular and statistically sound data collection to underpin European fisheries management. Solutions are proposed for future MRF data collection in Europe and other regions to support sustainable fisheries management., Institut Français de Recherche pour l’Exploitation de la Mer; French Ministry of Fisheries Management; Greek National Data Collection Programme; European Commission, Data Collection Framework; Department for Environment, Food and Rural Affairs, Grant/Award Number: MF1221, MF1230 and MI001; Norges Forskningsråd, Grant/Award Number: A framework for science-based management of marine recreational fisheries in Norway (267808); State Department of Agriculture, Food Security and Fisheries Mecklenburg- Western Pomerania; Interreg IVa 2 Seas, Grant/Award Number: GIFS project; Dutch Ministry of Economic Affairs, Grant/Award Number: WOT (Wettelijke Onderzoekstaken) programme; European Fishery Fund - Axis 4, approved by FLAG; Department of Environment, Planning, Agriculture and Fisheries from the Basque Government; Government of Galicia, Grant/Award Number: RECREGES project (ED481B2014/034-0)

Several anguillid eel species have experienced severe population declines over the past decades, particularly the European eel (Anguilla anguilla), which is listed as critically endangered by the International Union for Conservation of Nature. To reduce fishing mortality, many European countries have introduced strict recreational eel fishing regulations increasing regulatory catch-and-release (C&R) practice. Despite high release rates, only limited information exists on the potential consequences of C&R on eels. A field experiment was conducted with pre-tagged eels in a semi-natural environment to investigate lethal and sublethal impacts of C&R. The experiment was combined with a citizen science study evaluating the effects of different hooks on catch rates, fish size, and hooking location to develop best practice guidelines. Short-term mortality (≤72 h) ranged from 0.0–18.2%, and adjusted long-term mortality (>72 h) from 0.0–46.2% depending on treatments, resulting in adjusted total mortality rates between 8.4% and 64.4% at the end of the study period (≥43 d). The only significant predictor of mortality was the occurrence of bleeding from hooking injuries. Deep hooking was common, and only few deep-hooked eels for which the fishing line was cut and the hook left in place shed the hook after release. However, no significant effect of C&R on eel condition was found. The citizen science study showed that anglers can significantly decrease the catch of small eels, and thus release rates, by using large J-hooks. Furthermore, large J-hooks or circle hooks reduced the likelihood of deep hooking compared to small J-hooks. Post-release mortality of eels caught in recreational fisheries needs to be considered in future stock assessments and management plans to ensure conservation of the European eel. This study also highlights the strength of combining citizen science with experimental studies to develop best practice guidelines promoting fish conservation.

Weltersbach, M. S., and Strehlow, H. V. 2013. Dead or alive—estimating post-release mortality of Atlantic cod in the recreational fishery. – ICES Journal of Marine Science, 70: 864–872. Atlantic cod (Gadus morhua) is one of the most important commercial and recreational target species in European marine waters. Recent recreational fisheries surveys revealed that recreational cod catches and release rates are substantial compared to the commercial fishery, particularly in the western Baltic Sea. Despite high release rates, no literature exists exploring the post-release mortality of cod and potential sublethal effects after catch-and-release in recreational fisheries. This study investigates (i) the post-release mortality of undersized cod, (ii) potential factors affecting mortality, and (iii) consequences of the catch-and-release process on cod. During four experimental trials, western Baltic Sea cod were angled from a charter vessel and thereafter observed together with control fish in netpens for 10 d at holding temperatures between 6.2 and 19.8°C. Adjusted mortality rates for angled cod ranged from 0.0–27.3% (overall mean 11.2%). A logistic regression analysis revealed that bleeding and holding-water temperature were the only significant predictors of mortality. Slow hook injury healing (>10 d) and bacterial wound infections were observed in some surviving cod. The results will help to increase the accuracy of recreational cod removal estimates and thereby improve the management of western Baltic cod stock.

Atlantic cod (Gadus morhua) caught in recreational fisheries are commonly released, often with barotrauma after rapid decompression. Mouth-hooked, non-bleeding cod kept in a floating net pen showed mortalities ≥40% when angled from >50 m depth, likely because of cumulative stress from ongoing barotrauma and exposure to warm surface water. In a natural setting, however, cod have the opportunity to descend after release and are not restricted to the surface. In a follow-up study, 97.8% of similarly selected cod managed to dive following immediate release, whereas 2.2% were floaters. No mortality was observed for divers kept in cages, which were lowered to capture depth for 72 h. While the floaters would likely have died in a natural setting, no mortality was observed when they were recompressed and kept at capture depth for 72 h. The occurrence of swim bladder ruptures, swollen coelomic cavities, venous gas embolisms, and gas release around the anus was significantly influenced by capture depth (range 0–90 m). A supplementary radiology study showed inflated swim bladders in 87% of the cod after 72 h, and most barotrauma signs had disappeared after 1 month. This study encourages investigation of survival potential for physoclistous species when high mortalities are assumed but undocumented. Matching natural post-release and containment environment is essential in the experimental setup, as failure to do so may bias survival estimates, particularly when a thermocline is present. Assuming minimal predation, short-term mortality of cod experiencing barotrauma is negligible if cod submerge quickly by themselves and are otherwise not substantially injured. Survival of floaters may be increased by forced recompression to capture depth. Sublethal and long-term impacts of barotrauma remain to be studied. To ensure that cod have sufficient energy to submerge, anglers are encouraged to avoid fighting the fish to exhaustion and to minimize handling before release.

Ferter, Keno et al., While catch-and-release (C&R) is a well-known practice in several European freshwater recreational fisheries, studies on the magnitude and impact of this practice in European marine recreational fisheries are limited. To provide an overview of the practice and magnitude of C&R among marine recreational anglers in Europe, the existing knowledge of C&R and its potential associated release mortality was collected and summarized. The present study revealed that in several European countries over half of the total recreational catch is released by marine anglers. High release proportions of >60% were found for Atlantic cod (Gadus morhua), European sea bass (Dicentrarchus labrax), pollack (Pollachius pollachius), and sea trout (Salmo trutta) in at least one of the studied European countries. In the case of the German recreational Baltic Sea cod fishery, release proportions varied considerably between years, presumably tracking a strong year class of undersized fish. Reasons for release varied between countries and species, and included legal restrictions (e.g. minimum landing sizes and daily bag limits) and voluntary C&R. Considering the magnitude of C&R practice among European marine recreational anglers, post-release mortalities of released fish may need to be accounted for in estimated fishing mortalities. However, as the survival rates of European marine species are mostly unknown, there is a need to conduct post-release survival studies and to identify factors affecting post-release survival. Such studies could also assist in developing species-specific, best-practice guidelines to minimize the impacts of C&R on released marine fish in Europe. © 2013 International Council for the Exploration of the Sea.

The European eel (Anguilla anguilla) is a commercially and recreationally important fishery target species. In the last decades, the eel has experienced dramatic stock declines and has been listed as critically endangered. To reduce fishing mortality, several European countries have closed the fishery or introduced stricter management measures which increase the likelihood of catch-and-release in the recreational fishery. This study investigated hook shedding mechanisms of deep-hooked, line-cut eels via radiography, and quantified hook shedding rates, post-release mortality and sub-lethal effects in captivity. Eels were caught with four different hook treatments, monitored in a tank for 23 weeks, and radiographed 0, 1, 3, 10, 24, 54, 115 and 163 days after capture. After 163 days, total hook shedding rate was significantly higher for smaller hooks (41.2%) compared to larger hooks (0.0%), and increased with fish length. Post-release mortality rates ranged between 27.3% and 50.0% after 23 weeks (not adjusted for handling and holding) and did not differ significantly between hook treatments. The majority of dead eels showed gastric perforations caused by the hooks leading to internal haemorrhaging and the intrusion of digestive fluids into the body cavity inducing lethal degradation and inflammation of vital organs. Anglers are encouraged to minimise bycatch of eel in countries where eel harvest is prohibited. Anglers targeting eel should use selective and appropriate fishing gears, baits and tactics (e.g. very large hooks, immediate hook setting after a bite) to reduce deep hooking and the catch of undersized eels, ultimately promoting the eel's conservation. publishedVersion