Are the effects of catch-and-release angling evident in changes to mRNA abundances related to metabolism, acid-base regulation and stress in lake trout (Salvelinus namaycush) gills?

Catch-and-release (C&R) angling is a conservation-oriented practice intended to reduce the impact recreational angling has on fish populations. Even though most recreationally angled fish are released, little is known about how C&R angling impacts fish at the cellular or tissue level. As the first to explore the impacts of C&R angling on mRNA abundances, our study aimed to identify how the stress of angling influenced metabolism, acid-base regulation and cellular stress in the gills of lake trout (Salvelinus namaycush). Because gills are responsible for metabolic gas exchange, are crucial sites of acid-base homeostasis and respond to stressors quickly, we hypothesized that the relative mRNA abundance of genes related to these three physiological processes would be altered after angling. We took gill samples of live lake trout at 0, 2 or 48 h after fish were angled by rod and reel, and then used quantitative PCR (qPCR) to measure the relative abundance of nine candidate mRNA transcripts. Heat shock protein 70 (hsp70) mRNA levels significantly increased over 5-fold 2 h after angling, indicating a potential activation of a cytoprotective response. However, contrary to our hypothesis, we observed no change in the relative mRNA abundance of genes related to metabolism or acid-base regulation in response to C&R angling within a 48-h period. As C&R angling can negatively impact fish populations, further use of transcript-level studies will allow us to understand the impact C&R has on specific tissues and improve our knowledge of how C&R influences overall fish health.

Mental Health and Recreational Angling in UK Adult Males: A Cross-Sectional Study.

Exposure to aquatic environments (i.e., blue spaces) can lead to improved mental health and well-being. One meaningful way to spend time in blue spaces is through recreational angling, although limited scientific literature exists on this topic. The present study aims to examine the relationship between recreational angling and mental health and well-being in a sample of UK adult male anglers. A cross-sectional online survey asked questions about demographic characteristics, participation in recreational angling, physical activity levels, diagnosis of psychiatric disorders, and mental health and well-being. Relationships between angling status (i.e., how often and how long participants angled for) and mental health variables were determined using regression models adjusted for age. In total, 1752 participants completed the survey. The regression models found that those who took part in angling more regularly had reduced odds of having depression (p < 0.001), schizophrenia (p = 0.001), suicidal thoughts (p < 0.001), and deliberately self-harming (p = 0.012), in addition to having a higher mental well-being and lower symptoms of depression and anxiety compared to those taking part in angling less frequently. In general, the findings suggest that encouraging frequent participation in recreational angling could be a dual method strategy for promoting relaxation and positive mental health, as well as encouraging increased levels of physical activity in those with mental health issues.

The Relationship between Social Support Correlates and Feelings of Loneliness among Male UK Recreational Anglers.

The benefits of access to blue spaces (exposure to aquatic environments) have been well reported. One common activity conducted in these spaces is recreational angling. Studies have shown that several correlates are associated with recreational angling, including a lower incidence of anxiety disorders compared to non-anglers. What is currently unknown is how measures of social support relate to feelings of loneliness in this population. The aim of this study, therefore, is to examine experiences of loneliness and social support in male UK anglers. In total, 1752 participants completed an online survey. The results of this study showed that the higher the number of friends or family that anglers hear from and feel close to, the less likely they are to report a lack of companionship, the less likely they are to report feeling left out, and the less likely they are to report feelings of isolation. Furthermore, more than half of the sample reported hardly ever or never having feelings of loneliness, suggesting that recreational angling does not affect feelings of loneliness.

Global responses to the COVID-19 pandemic by recreational anglers: considerations for developing more resilient and sustainable fisheries.

The global COVID-19 pandemic resulted in many jurisdictions implementing orders restricting the movements of people to inhibit virus transmission, with recreational angling often either not permitted or access to fisheries and/or related infrastructure being prevented. Following the lifting of restrictions, initial angler surveys and licence sales suggested increased participation and effort, and altered angler demographics, but with evidence remaining limited. Here, we overcome this evidence gap by identifying temporal changes in angling interest, licence sales, and angling effort in world regions by comparing data in the 'pre-pandemic' (up to and including 2019); 'acute pandemic' (2020) and 'COVID-acclimated' (2021) periods. We then identified how changes can inform the development of more resilient and sustainable recreational fisheries. Interest in angling (measured here as angling-related internet search term volumes) increased substantially in all regions during 2020. Patterns in licence sales revealed marked increases in some countries during 2020 but not in others. Where licence sales increased, this was rarely sustained in 2021; where there were declines, these related to fewer tourist anglers due to movement restrictions. Data from most countries indicated a younger demographic of people who participated in angling in 2020, including in urban areas, but this was not sustained in 2021. These short-lived changes in recreational angling indicate efforts to retain younger anglers could increase overall participation levels, where efforts can target education in appropriate angling practices and create more urban angling opportunities. These efforts would then provide recreational fisheries with greater resilience to cope with future global crises, including facilitating the ability of people to access angling opportunities during periods of high societal stress. Supplementary Information: The online version contains supplementary material available at 10.1007/s11160-023-09784-5.

The role of salinity in recovery of white sturgeon (Acipenser transmontanus) from stimulated angling stress.

White sturgeon (Acipenser transmontanus) in the Lower Fraser River are the focus of a catch-and-release angling fishery in British Columbia, Canada. However, the lower region of the catch area includes areas where tidal waters invade, and the consequence of salinity levels on recovery from an angling challenge are not characterized in sturgeon, despite theoretical implications of its import. We acclimated white sturgeon to various salinities (0, 10 and 20‰ (parts per thousand)) to investigate the effects of acclimation on recovery from stimulated angling stress that was induced through manual chasing. This challenge elicited the traditional physiological responses such as ion homeostasis disturbance, increases in secondary stress indicators and metabolic acidosis; however, environmental salinity altered the timing of recovery in some of the parameters measured. In addition, the severity of the intracellular pH disturbance in both heart and red blood cell seemed to be mediated in fresh water, yet the recovery pattern of plasma chloride and bicarbonate ions seemed to be facilitated by higher salinity. In general, responses were similar but not identical, leading us to conclude that the role of salinity on recovery from exercise is complex but not insignificant. Salinity may be important to behaviours exhibited by white sturgeon (such as migrations) in their respective saline environments, but less so around the impact of an angling stressor. Further exploration of this response may provide insight on whether the current tidal boundaries for angling white sturgeon are appropriate.

Freshwater protected areas can preserve high-performance phenotypes in populations of a popular sportfish.

Recreational fishing has the potential to cause evolutionary change in fish populations; a phenomenon referred to as fisheries-induced evolution. However, detecting and quantifying the magnitude of recreational fisheries selection in the wild is inherently difficult, largely owing to the challenges associated with variation in environmental factors and, in most cases, the absence of pre-selection or baseline data against which comparisons can be made. However, exploration of recreational fisheries selection in wild populations may be possible in systems where fisheries exclusion zones exist. Lakes that possess intra-lake freshwater protected areas (FPAs) can provide investigative opportunities to evaluate the evolutionary impact(s) of differing fisheries management strategies within the same waterbody. To address this possibility, we evaluated how two physiological characteristics (metabolic phenotype and stress responsiveness) as well as a proxy for angling vulnerability, catch-per-unit-effort (CPUE), differed between populations of largemouth bass (Micropterus salmoides) inhabiting long-standing (>70 years active) intra-lake FPAs and adjacent, open access, main-lake areas. Fish from FPA populations had significantly higher aerobic scope (AS) capacity (13%) and CPUE rates compared with fish inhabiting the adjacent main-lake areas. These findings are consistent with theory and empirical evidence linking exploitation with reduced metabolic performance, supporting the hypothesis that recreational fishing may be altering the metabolic phenotype of wild fish populations. Reductions in AS are concerning because they suggest a reduced scope for carrying out essential life-history activities, which may result in fitness level implications. Furthermore, these results highlight the potential for unexploited FPA populations to serve as benchmarks to further investigate the evolutionary consequences of recreational fishing on wild fish and to preserve high-performance phenotypes.

Parasites either reduce or increase host vulnerability to fishing: a case study of a parasitic copepod and its salmonid host.

Parasites generally increase host vulnerability to predators via host manipulation for trophic transmission and reduction of host activities. Predators also select prey depending on the parasite infection status. Despite such parasites' roles in prey-predator interactions in wild animals, how parasites affect human hunting probability and resource consumption remains unknown. We examined the effects of the ectoparasitic copepod Salmincola cf. markewitschi on fish vulnerability to angling. We found that infected fish were less vulnerable compared with non-infected fish when the fish body condition was low, which was probably due to reduced foraging activity. On the contrary, infected fish were more vulnerable when the host body condition was high, probably due to the compensation of parasites' negative effects. A Twitter analysis also suggested that people avoided eating fish with parasites and that anglers' satisfaction decreased when captured fish were parasitized. Thus, we should consider how animal hunting is affected by parasites not only for catchability but also for avoiding parasite infection sources in many local regions.

The effects of size on exhaustive exercise and recovery in a marine sportfish, the red drum (Sciaenops ocellatus).

Recreational angling is an economically important activity in many communities around the world. One conservation strategy adopted to offset the population-level consequences of recreational angling is "catch-and-release" (CAR), which is the act of returning fish to the environment following an angling event. While an expansive literature has helped to generalize CAR best practices, species-specific validation of recovery profiles remains a crucial component of species-specific angling guidance. This study sought to define the injury and recovery profiles in the plasma and white muscle following exhaustive exercise in two size classes of a common Gulf of Mexico sportfish, the red drum (Sciaenops ocellatus). The two sizes included a "small" (20-30 cm) and "slot" size (51-74 cm), the latter of which is a common angling target. Both size classes showed a characteristic injury profile that consisted of significantly elevated muscle and plasma lactate, plasma osmolality and haematocrit, as well as decreased muscle ATP and phosphocreatine, and lowered plasma and muscle pH. In small fish, muscle metabolites returned to control values by 1 h post-exercise and plasma metabolites returned to control between 3 and 6 h post-exercise. In contrast, slot sized fish had recovery periods of ≥3 h for all metabolites. The maximum injury effect size was also greater in the slot size class. These data suggest that while red drum conform to typical patterns of post-exercise recovery, larger trophy-sized fish may be more at risk to the ancillary effects of exhaustive exercise owing to greater exercise injury and slower recovery rates.

The Size Screening Could Greatly Degrade the Health Risk of Fish Consuming Associated to Metals Pollution-An Investigation of Angling Fish in Guangzhou, China.

Fish size can heavily impact the bioaccumulation of metals, but it was rarely applied to screen out the fish with low health risk for consuming. Given the widespread metals contamination of angling fish, the angling fish collected from Guangzhou, China, were taken as an example in this study. The screening length and weight were detailed in accordance with the investigation of metals contamination among angling fish. Importantly, the feasibility of size screening on mitigating the health risk of angling fish was evaluated. The results revealed that the concentration of Cr and As were relatively high and beyond the maximum residue limit (MRL) in some fish. The mean pollution index (Pi) of As, Cr, and Pb were beyond 0.2, suggesting the widespread minor contamination. The total metal pollution index (MPI) manifested Oreochroms mossambcus was the most contaminated. The target hazard quotient (THQ) of Cr, As, and Hg were relatively higher, but the higher probability of THQ > 1 indicated the health risk should be dominantly from As. The highest TTHQ suggested the highest risk of Oreochroms mossambcus. Regression analysis determined the fish of THQ < 1 should be more likely centralized in the size that is beyond 13.7 cm and 45.0 g for adults and 19.8 cm and 127.9 g for children. Significantly reducing THQ among these screened fish confirmed their effect on the degrading health risk of metals; particularly, the children's THQ returned below 1. The commonly contaminated Oreochroms mossambcus was further excluded to remove the screened fish with THQ > 1; the further decrease in THQ confirmed that the exclusion of a contaminated species could improve the effect of size screening.

Allometric Scaling of Anaerobic Capacity Estimated from a Unique Field-Based Data Set of Fish Swimming.

AbstractLocomotion is a defining characteristic that can dictate many aspects of an organism's life history in the pursuit of maximizing fitness, including escaping predators, capturing prey, and transitioning between habitats. Exhaustive exercise can have negative consequences for both short-term and long-term energetics and life history trade-offs, influencing fish survival and reproduction. Studies of swimming performance and exhaustive exercise in fish are often conducted on individual species, but few multispecies analyses exist and even fewer in field settings. In fish, swimming performance and exercise have historically been studied in the laboratory using swim tunnels, but an increasing body of work in recreational fisheries science provides a novel way to examine swimming capacity and exhaustion. Using fight time, the time it takes for a hooked fish to be landed on rod and reel fishing gear, as an opportunistic proxy for fish exhaustion, a multispecies meta-analysis of data from studies on recreational fisheries was conducted to elucidate the factors that most influence capacity for exhaustive exercise. Data from 39 species of freshwater and marine fish were aggregated, and negative binomial mixed effects models as well as phylogenetic least squares regression were used to identify the factors that most influenced exhaustive exercise in the field. Fish total length, aspect ratio of the caudal fin, and body form were significant factors in explaining the capacity for exhaustive exercise. Large migratory fish with high aspect ratios were able to fight, and therefore exercise, the longest. These results illustrate that body form and physiology are both deeply intertwined to inform function across fish species and point to angling fight time as a useful approximation of fish swimming capabilities that can be further developed for understanding the limits of fish exercise physiology.

A review of elasmobranch catch-and-release science: synthesis of current knowledge, implications for best practice and future research directions.

Until relatively recently commercial fisheries have been considered the main driving factor for elasmobranch population declines. However, this belief has begun to shift with the realization that recreational elasmobranch catches may equal or exceed commercial catches in some regions. Many recreational angling fisheries for elasmobranchs involve high participation in catch-and-release angling practices. However, high release rates may not necessarily equate to high survival rates. Therefore, to assist accurate assessment of the potential impact of recreational angling on elasmobranchs, we attempted to summarize and integrate currently available information on specific risk factors associated with recreational angling, alongside associated mortality rates, as well as information on angler behaviour as it relates to identified risk factors. We categorized the major angling-related effects into two groups: injury-induced effects; and biochemical disruption-induced effects; providing a summary of each group and outlining the main lethal and sub-lethal outcomes stemming from these. These outcomes include immediate and delayed post-release mortality, behavioural recovery periods (which may in-turn confer increased predation risks), chronic health impacts and capture-induced parturition and abortion. Additionally, we detailed a range of angling practices and equipment, including hook-type, hook removal and emersion (i.e. air exposure), as well as inter- and intra-specific factors, including aerobic scope, respiratory mode, body size and species-specific behaviours, which are likely to influence injury and/or mortality rates and should therefore be considered when assessing angling-related impacts. We then utilized these data to provide a range of actionable recommendations for both anglers and policymakers which would serve to reduce the population-level impact of recreational angling on these enigmatic animals.

After the spawn and on the hook: Sea trout Salmo trutta biophysical responses to different components of catch and release in a coastal fishery.

This study investigated the biophysical responses of sea run brown trout Salmo trutta to catch-and-release in the coastal fishery around Gotland, Sweden. It used information recorded on individual angled S. trutta (n = 162), including fight time, handling time, total air exposure time, injury, bleeding, fish length, body condition, spawning status, water temperature, hook location and difficulty of hook removal. Reflex action mortality predictors (equilibrium, operculum beats, tail grab response, body flex response and vestibular-ocular response), tests of blood glucose and lactate, and observation of hooking injury were used to measure the relative impact of the angling event on the fish's physical state and stress experienced. The results of this study suggest low rates of post-release mortality and generally limited stress responses to angling events, and relatively high post-release survival supported by the recapture of many tagged S. trutta. However, a number of scenarios were identified in which stress responses are likely to be compounded and where anglers should take additional action to reduce sublethal physiological disturbances and the risk of delayed mortality. Particular care should be taken to limit cumulative total air exposure to <10 s, and to reduce handling time and risk of additional injury in angling events with extended fight times, when water temperatures >10°C, or where S. trutta show evidence of being physically compromised by injury or having recently spawned. The results also indicate the importance of using appropriately sized single hooks rather than larger treble hooks to reduce hooking injury and handling time during unhooking.

The impact of the COVID-19 pandemic on a recreational rainbow trout (Oncorhynchus mykiss) fishery.

There has been a recent flurry of publications describing the potential effects of the COVID-19 pandemic on both commercial and recreational fisheries. As of yet, studies have only provided insights from researchers or industry experts detailing perceived consequences, or from survey data indicating modifications in angler activity levels and behaviours. Using real recreational fisheries data from an ongoing radio telemetry study (2018-present), we explored changes in the relative exploitation rates of rainbow trout (Oncorhynchus mykiss; Walbaum 1792) in the Saugeen River, Ontario, a tributary to Lake Huron, before compared to during the pandemic. Restrictions on site access that affected the implementation of important management activities that usually support this popular fishery are also discussed. During the initial phase of complete public lock-downs imposed during spring 2020, angler exploitation rates decreased to half that reported prior to the pandemic. Fishway operations were temporarily suspended and hatchery efforts were interrupted. Once restrictions began to ease in fall 2020, there was an eight-fold increase in overall exploitation rate and a four and a half-fold increase in harvest rate compared to seasons prior to the pandemic. While the full impact of the ongoing pandemic on the Lake Huron fishery is not likely to be fully realized for several years, the potential effects on future return run sizes may need to be considered by fisheries managers monitoring trends in population escapement.

Fishing Participation, Motivators and Barriers among UK Anglers with Disabilities: Opportunities and Implications for Green Social Prescribing.

Green social prescribing, which includes the referral of patients to nature-based activities, could exacerbate inequalities between people with disabilities and people without. Research suggests fishing could be more inclusive relative to other outdoor sports. To understand if fishing is an inclusive sport, and the potential benefits and barriers to prescribing fishing, the present study compared participation, motivators and barriers to fishing, between anglers with and without disabilities. UK adults were invited to participate in an online survey. Chi-square tests examined differences between anglers with and without disabilities regarding the type of fishing anglers engaged in, the frequency of fishing, the length of time spent fishing, motivators for fishing and barriers to fishing. Among 1799 anglers (97.5% male), 292 (16.2%) anglers reported having a disability. Most anglers with disabilities were over 55 years old (56.5%). There was no difference in fishing participation, or motivators for fishing, between anglers with and without disabilities; however, anglers with disabilities were more likely to report 'costs', 'lack of transport' and 'having no one to go with them' as barriers. Overall, there appeared to be no differences in fishing participation between anglers with versus without disabilities, although additional barriers to participation may exist.

A Bayesian Modelling Framework for Integration of Ecosystem Services into Freshwater Resources Management.

Models of ecological response to multiple stressors and of the consequences for ecosystem services (ES) delivery are scarce. This paper describes a methodology for constructing a BBN combining catchment and water quality model output, data, and expert knowledge that can support the integration of ES into water resources management. It proposes "small group" workshop methods for elucidating expert knowledge and analyses the areas of agreement and disagreement between experts. The model was developed for four selected ES and for assessing the consequences of management options relating to no-change, riparian management, and decreasing or increasing livestock numbers. Compared with no-change, riparian management and a decrease in livestock numbers improved the ES investigated to varying degrees. Sensitivity analysis of the expert information in the BBN showed the greatest disagreements between experts were mainly for low probability situations and thus had little impact on the results. Conversely, in our applications, the best agreement between experts tended to occur for the higher probability, more likely, situations. This has implications for the practical use of this type of model to support catchment management decisions. The complexity of the relationship between management measures, the water quality and ecological responses and resulting changes in ES must not be a barrier to making decisions in the present time. The interactions of multiple stressors further complicate the situation. However, management decisions typically relate to the overall character of solutions and not their detailed design, which can follow once the nature of the solution has been chosen, for example livestock management or riparian measures or both.

Previous experience alters individual vulnerability to angling of crucian carp (Carassius auratus).

In recreational fisheries, fish often undergo catch-and-release angling, which can lead to an indirect selection response of the behavioral traits of the fish. As individuals experience high-intensity angling activities, individuals learn to avoid being selected for artificial bait again, resulting in a change in the vulnerability to angling of fish, which is partly dependent on the cognitive learning ability of the fish. Here, we examined the relationship between vulnerability to angling and learning in juvenile crucian carp (Carassius auratus) under laboratory conditions. Our study had six angling treatments with each containing different group mates (i.e., the angling stress group, all fish that only experienced repeated angling stress practice for a period of three days; the learning group, all fish that only observed individual in the angling stress group to be angled; the control group, all fish that did not undergo any angling or learning; the mixed Group 1, fish are from the control and learning groups; the mixed Group 2, fish are from the control and angling stress groups; the mixed Group 3, fish are from the learning and angling stress groups), each of which consisted of five replicates). All fish were tested for boldness before and after the previous experiences (i.e., angling stress or learning) test. Our results showed that for the stress group, the total angling time, mean individual angling time and total number of bait touches all increased from Day 1 to Day 3, and the total angling rate decreased during the three days of the angling stress practice. After encountering the previous experiences, fish in the control, stress and learning groups all had increased boldness, as assessed by a shortened percent latency to emerge from the refuge. The change in the percent latency of boldness was higher in the stress group than in the learning group, with the control group being intermediate. Furthermore, no differences in the total angling time and total number of bait touches were detected among the six angling treatments, but the stress group exhibited the longest mean individual angling time and lowest angling rate compared with the other five angling treatments, indicating that angling-stressed individuals greatly decreased their vulnerability to angling after the previous angling stress. Our results show that changes in the vulnerability of crucian carp to angling were related to previous individual angling experience but not to visual social learning.

Assessing the impact of management on sea anglers in the UK using choice experiments.

Recreational sea angling is a popular activity generating significant socio-economic benefits but can impact on fish stocks. The motivations of recreational sea anglers go beyond catch, with a diverse range of motivations relating to physical health and well-being. Heterogenous motives and the popularity of catch and release practices mean that applying commercial fisheries management goals (maximum sustainable yield) to recreational fisheries could result in reduced participation, increased non-compliance, and a subsequent loss of both market and non-market values generated through recreational angling activities. Hence, assessment of sea angler preferences for management is important for the development of appropriate management strategies. In this study, a choice experiment was conducted to assess sea anglers' preferences for changes in UK sea angling management measures. Stated preferences for catching, keeping, and releasing fish due to bag limits and minimum-landing sizes were assessed. Willingness to pay (WTP) estimates for marginal changes of catching the first sea bass on a trip were between £11 and £31 depending on whether the fish could be kept or released and between £11 and £28 for cod, respectively. WTP was much higher for fish caught and kept than caught and released suggesting that consumption of fish was an important motivation. Minimum size was the most considered choice attribute for respondents, while cost was less commonly considered. The implications of the findings are discussed in the context of future management of recreational fisheries.

Has stocking contributed to an increase in the rod catch of anadromous trout (Salmo trutta L.) in the Shetland Islands, UK?

The stocking of hatchery-origin fish into rivers and lakes has long been used in fisheries management to try to enhance catches, especially for trout and salmon species. Frequently, however, the long-term impacts of stocking programmes have not been evaluated. In this study, the authors investigate the contribution of a stocking programme undertaken to support the rod catch of sea trout in the Shetland Islands, UK. Once a highly productive recreational fishery, Shetland sea trout catches crashed in the mid-1990s. Around the time that stocking began, increases in rod catches were also reported, with advocates of the stocking highlighting the apparent success of the programme. Using a suite of genetic markers (microsatellites), this study explores the contribution of the stocking programme to the Shetland sea trout population. The authors found that the domesticated broodstock and wild spawned brown trout from seven streams were genetically distinct. Despite extensive stocking, wild spawned brown trout dominated, even in those streams with a long history of supplementation. The majority of sea trout caught and analysed were of wild origin - only a single individual was of pure stocked origin, with a small number of fish being of wild × stocked origins. This study suggests that stocking with a domesticated strain of brown trout has made only a very limited contribution to the Shetland Islands rod catch, and that the revival of sea trout numbers appears to be driven almost exclusively by recovery of trout spawned in the wild.

COVID-19 restrictions and recreational fisheries in Ontario, Canada: Preliminary insights from an online angler survey.

The COVID-19 pandemic and corresponding public health mitigation strategies have altered many facets of human life. And yet, little is known about how public health measures have impacted complex socio-ecological systems such as recreational fisheries. Using an online snowball survey, we targeted resident anglers in Ontario, Canada, to obtain preliminary insights on how the pandemic has impacted recreational fishing and related activity. We also explored angler perspectives on pandemic-related restrictions and other aspects of fisheries management. Our results point to the value of recreational fisheries for the mental and physical well-being of participants, as well as the value and popularity of outdoor recreation during a pandemic. Although angling effort and fish consumption appeared to decline during the early phases of the pandemic, approximately 21 % of the anglers who responded to our survey self-identified as new entrants who had begun or resumed fishing in that time. Self-reported motivations to fish during the pandemic suggest that free time, importance to mental and physical health, and desires for self-sufficiency caused some anglers to fish more, whereas a lack of free time, poor or uncertain accessibility, and perceived risks caused some anglers to fish less. Respondents also expressed their desires for more clear and consistent communication about COVID-19 fishing restrictions from governments, and viewed angling as a safe pandemic activity. Information on recreational angler behaviours, motivations, and perspectives during the pandemic may prove valuable to fisheries managers and policy makers looking to optimize their strategies for confronting this and other similar crises.

Analyzing publicly available videos about recreational fishing reveals key ecological and social insights: A case study about groupers in the Mediterranean Sea.

iEcology and conservation culturomics are two emerging research approaches that rely on digital data for studying ecological patterns and human-nature interactions. We applied data mining of videos published on YouTube related to recreational fishing of four species of groupers (family: Epinephelidae) in Italy between 2011 and 2017 to learn whether digital user-supplied data help uncover key spatio-temporal ecological patterns characteristic of the studied species. Our results support an ontogenetic deepening of the dusky grouper (Epinephelus marginatus) as revealed by a positive relationship between body mass and depth of captures declared in spearfishing videos. In addition, the data support a northward expansion of the white grouper (Epinephelus aeneus) because the average latitude associated to the catch was found to be positively correlated with the years when the videos were uploaded on YouTube. Furthermore, the georeferenced data about the white grouper filled a knowledge gap in a well-established international occurrence records dataset. The approach presented here could help mitigating data deficiencies and inform about harvesting patterns shown by recreational anglers and spearfishers. Our work illustrates the value of digital data associated with recreational fishing for advancing fish and fisheries research. The approach can be broadened to larger spatial and temporal scales, and to different species, contributing to a better understanding of macroecological patterns, assessment and conservation of exploited species, and monitoring of recreational fisheries.