Long-term shifts in the growth and maturation size of Miyabe charr <Emphasis Type="Italic">Salvelinus malma miyabei</Emphasis>

Overfishing can affect life history traits, resulting in population collapse and oftentimes a decrease in length-at-age and maturation size in fish populations. However, little is known about the recovery mechanisms and time scales of these traits in exploited wild populations. In the study reported here, we documented long-term shifts in growth and mature size in Miyabe charr Salvelinus malma miyabei associated with a history of recreational fishing in Lake Shikaribetsu for approximately 80 years. Downsizing in the charr was observed when the charr population collapsed due to intensive recreational fishing. However, subsequent moratoriums and the introduction of fishing regulations, especially the implementation of a catch-and-release policy, during the following 10–30 years facilitated the recovery of population size, length-at-age and mature fish size. This study provides important insights into the biological changes and required recovery time scales of a heavily harvested population and supports management and conservation strategies.     

Angling for endangered fish: conservation problem or conservation action?

Recreational angling has been implicated in population declines of some marine and freshwater fish, but this activity is rarely considered as a threat or even halted when endangered species are targeted. Indeed, in some cases, anglers are drawn to fish for rare or endangered species. Conservation‐oriented behaviours such as catch‐and‐release are often practiced voluntarily due to the ethics of anglers, yet even in these cases, some fishing mortality occurs. Nonetheless, there are many indirect conservation benefits associated with recreational angling. Here, we present a series of case‐studies and consider whether catch‐and‐release angling for endangered fish is a conservation problem or a conservation action. If recreational angling activities contribute to population‐level consequences that are contrary to recovery strategies, then angling for endangered species would seem to be a poor option. However, as revealed by several case‐studies, there is much evidence that anglers are vocal and effective proponents of fish and habitat conservation, and for endangered species, they are often the only voice when other stakeholders are not engaged. Anglers may contribute directly to conservation actions via user fees (e.g. licences), philanthropic donations or by volunteering in research, education and restoration activities. However, it is important to quantify post‐release mortality as well as understand the full suite of factors influencing a given population or species to know the potential risks. A risk assessment approach outlined in the paper may be used by managers to determine when the benefits of angling for endangered species outweigh the risks.     

Catching sharks: recreational saltwater angler behaviours and attitudes regarding shark encounters and conservation

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Population assessment of sockeye salmon Oncorhynchus nerka caught by recreational angling and commercial fishery in Lake Toya, Japan

ABSTRACT: We carried out mail and access point surveys to estimate the catch numbers, angling effort of recreational angling and the population of sockeye salmon Oncorhynchus nerka in Lake Toya in 1998 and 1999. The mail survey questions in questionnaires distributed to anglers with a recreational angling license included date of angling, caught fish species and size, and catch number. In the access point survey we also asked anglers if they had a license. We measured the fork length and weight of caught fish. The catch rate (catch number in a day by each angler) from both surveys showed no significant difference, suggesting no bias for the catch rate between surveys. The estimated total angling effort was 1760 people (1998), and 1516 people (1999). The estimated recreational catch was 28 889 (1998) and 5455 (1999), that is, two or three times larger than the commercial catch. The fish population was estimated by using the DeLury method as 60 262 (1998) and 10 806 (1999). The total exploitation rate was 62% (1998) and 78% (1999). The size of caught fish was much larger in 1999 than 1998 because of the difference in age composition.     

Estimation of northern pike population sizes via mark–recapture monitoring

Abstract Estimates of population size are needed in populations targeted by recreational fisheries, to determine their conservational status and to formulate fishing regulations. Mark–recapture monitoring is a promising tool for this because of the increased popularity of catch‐and‐release angling. Northern pike, Esox lucius L., population sizes were estimated in four lakes based on experimental mark–recapture fishing using a hierarchical Bayesian model that also estimated natural mortality. The approach was compared with output from traditional Petersen’s population size estimates. Despite intensive fishing with multiple gears, the population size estimates suggested that a substantial proportion of individuals remained unobserved by fishing. Petersen’s estimates depended on the assumed rate of natural mortality, and no mortality rate scenario matched with the Bayesian estimates. Consequently, the number of individuals caught by recreational anglers is a poor proxy of population size for which estimations should be carried out using a modelling approach that also estimates natural mortality.     

Voluntary angler logbooks reveal long‐term changes in a lentic pike,Esox lucius,population

Sixty‐two years of voluntarily collected angling logbook data from a large natural Danish lake were used to study variation in pike, Esox lucius L., CPUE (catch per unit effort), expressed as no. of captured pike per boat trip, as an index of stock size. Pike CPUE was positively related to pike release rate by anglers and negatively affected by certain commercial fishers. The stocking of young‐of‐the‐year pike and a fishery‐dependent index of perch, Perca fluviatilis L., abundance (which may be pike prey or predator depending on size) did not correlate with pike CPUE. Analyses of the size distribution of pike, based on sizes of annual record trophy pike captured by anglers, confirmed the negative impact of commercial pike fishing and revealed a positive influence of air temperature. It is concluded that high‐quality angler logbooks that record effort and catch can be a cost‐effective tool to inform lake fisheries management by revealing long‐term population trends. Further, state space modelling, a statistical technique not yet seen in recreational fisheries science, is recommended as a tool to model proxies for population dynamics from angler logbook data.     

Recreational anglers as citizen scientists can provide data to estimate population size of pike,Esox lucius

Catch‐per‐unit‐effort is often used as an approximation of population size. However, for the management and conservation of populations, information about the number of individuals is fundamental. Pike, Esox lucius L., is a popular fish species for recreational anglers. In this study, data in the form of journal keeping by anglers were used: date; place; and photographs of the captured fish; pike were identified based on their natural markings in combination with length measurements. The data were analysed by spatial capture–recapture (SCR) models. Results showed that a small and densely vegetated lake (6.7 ha) in south‐eastern Sweden had a population size of 91 (±22 SE) pike ≥60 cm. On one occasion, 10 individuals were caught, that is 11.1% of the population, highlighting that angling may potentially have a substantial impact on the population size. Hopefully, this study can inspire angler–manager collaborations for conservation of fish stocks.     

Catch-and-release science and its application to conservation and management of recreational fisheries

Abstract  Catch-and-release angling is a well-established practice in recreational angler behaviour and fisheries management. Accompanying this is a growing body of catch-and-release research that can be applied to reduce injury, mortality and sublethal alterations in behaviour and physiology. Here, the status of catch-and-release research from a symposium on the topic is summarised. Several general themes emerged including the need to: (1) better connect sublethal assessments to population-level processes; (2) enhance understanding of the variation in fish, fishing practices and gear and their role in catch and release; (3) better understand animal welfare issues related to catch and release; (4) increase the exchange of information on fishing-induced stress, injury and mortality between the recreational and commercial fishing sectors; and (5) improve procedures for measuring and understanding the effect of catch-and-release angling. Through design of better catch-and-release studies, strategies could be developed to further minimise stress, injury and mortality arising from catch-and-release angling. These strategies, when integrated with other fish population and fishery characteristics, can be used by anglers and managers to sustain or enhance recreational fishing resources.     

An assessment of catches and harvest of recreational shore angling in the north of Portugal

Abstract  Recreational shore angling in the Atlantic Ocean between Moledo and Aveiro (Portugal) was examined using roving creel surveys (March/September 2001). Cooperation was high (90% of 2310 anglers approached). At least 39 species of fish were caught at a rate of approximately 0.5 fish angler h⁻¹. An estimated 7319 kg of Dicentrarchus labrax (L.), with 45.6% below the minimum legal size, and 2040 kg of sea breams (genus Diplodus ), correspond to 5.75% and 1.19% of the commercial landings in the same geographical area, respectively. The results shed light on a number of issues relevant to integrated coastal management, including temporal and spatial distribution of fishing effort, species caught, sizes of fish, catch rates, and factors influencing catches and angler satisfaction. Whilst the results suggest that the catches of sea breams and sea bass by day-time recreational shore angling in northern Portugal are small compared with commercial fishing, other recreational activities, such as boat fishing and spear-fishing, must be assessed.     

Effects of recreational fishing on zooplankton communities of drainage system reservoirs at an open‐pit mine

The use of artificial water bodies for angling is a popular practice, especially in industrial and urbanised areas where natural water bodies are lost. In this study, the zooplankton structure dynamics and water quality at three strip mine drainage system reservoirs were assessed with different types of recreational fishery exploitation: K1—intensive angling using the catch‐and‐release model, K2—lowest angling pressure and higher share of predatory fishes and K3—moderate fishing, that is limiting groundbait quantities and eliminating non‐predatory fishes by anglers. The null hypothesis tested was that recreational fishing does not affect the biotic and abiotic conditions of reservoirs. The significance of each environmental variable was tested using redundancy analysis (RDA). The highest nutrients and chlorophyll a concentration, turbidity level and organic matter content occurred in K1. Zooplankton diversity was the lowest under these conditions; protozoa and larval stages of copepods dominated. In reservoirs where sustainable fishing was implemented (K2, K3), trophic parameters of water were lower, on average, by 25%, turbidity by 30%, and productivity by 35–70%. Zooplankton diversity was significantly higher; rotifers and small cladocerans dominated. The choice of recreational fishing model determines the functionality and biological potential of the reservoir.     

Winners and losers of conservation policies for European eel,Anguilla anguilla: an economic welfare analysis for differently specialised eel anglers

Abstract Recreational specialisation theory was coupled with a discrete choice experiment to understand eel, Anguilla anguilla L., angler’s heterogeneity in their reaction to regulatory changes and the associated welfare changes. Differently specialised eel anglers exhibited distinct preferences for catch variables and eel angling regulations. All anglers preferred slightly to moderately stricter regulations than are currently in place; however, such policies particularly benefited casual eel anglers. In contrast, advanced eel anglers would be most penalised by highly restrictive regulations as indicated by substantial reductions in economic welfare. Aversions to stricter regulations found for advanced anglers contradicted predictions from specialisation theory. From an eel management perspective, the implementation of some simple tools such as increased minimum‐size limits will reduce angling mortality on eel and simultaneously increase the welfare of anglers. By contrast, highly restrictive eel angling regulations will result in considerable economic welfare losses of several million € per year for northern Germany alone.     

Explaining recreational angling catch rates of Eurasian perch,Perca fluviatilis: the role of natural and fishing‐related environmental factors

Angling catch records are frequently used to reveal fish population developments. It is therefore important to understand the determinants of angling catches. This study focused on angler‐related, biotic and abiotic factors influencing catchability of Eurasian perch, Perca fluviatilis L. A multi‐lake (21 lakes) study based on angling diaries collected in Mecklenburg‐Vorpommern, Germany (2006/2007), found that angler‐related factors such as fishing experience, species preference and bait/lure type had a large impact on perch catch rates. Additionally, environmental conditions (nutritional status and water transparency) affected either the size or the number of perch caught by anglers. Catch rates varied seasonally, which was confirmed by an experimental fishery on a gravel pit (2008). This portion of the study showed that altered food availabilities in the course of the year caused food limitation in perch, which in turn facilitated high catch rates and female‐biased exploitation in autumn. It is concluded that both angler‐related and abiotic factors interact affecting perch catch rates and size of perch captured in recreational angling.     

Non‐indigenous fish in protected spaces: Trends in species distribution mediated by illegal stocking

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Changes in the population density of pelagic salmonids in relation to changes in lake enrichment in Windermere (northwest England)

From July 1989 to December 1994, an echo sounder provided monthly estimates, usually for both day and night, of pelagic salmonid densities in the North and South Basins of Windermere, the largest natural lake in England. Sampling was along contiguous transects, three in the North Basin and five in the South Basin. Records for Arctic charr (Salvelinus alpinus) could not be separated from those for brown trout (Salmo trutta), but previous sampling by gill-nets and anglers showed that charr formed over 90% of this mixed population in the North Basin and about 60–75% in the South Basin. Associated with the increasing eutrophication of the lake, there has been a decline in anglers' catches of charr and, since 1984, an increase in brown trout taken in the pelagic zone of the South Basin. The echo-sounder data showed that pelagic salmonid density in the North Basin was about two to five times that in the more eutrophic South Basin in 1989, 1990 and 1991. Since the start, in April 1992, of the reduction of phosphorus discharged from sewage works, this ratio has decreased, especially at night when the highest densities were recorded. This improvement was chiefly due to a significant (P<0.001) increase in the density of small fish (length <20 cm), in both the upper (depth <20 m) and deeper (depth >20 m) water layers. Although a similar improvement has still to be shown in the upper water layer by larger fish above the size limit for removal by angling (20 cm), there has been a significant increase (P<0.01) in the density of these fish in the deeper water layer of the South Basin. The increased density of small fish suggests that the stock available to charr anglers (fish >20 cm at water depths <20 m) should increase in the next few years, especially in the South Basin. It is therefore important to continue the monitoring program and thus ensure that there is advance warning of any marked changes in charr stocks.     

Considering recreational catch and harvest in fisheries management at the bio‐regional scale

Abstract The Gulf of Carpentaria in northern Australia supports several commercial fisheries and a largely tourist‐based recreational fishery. The results of a survey of 427 recreational fishing parties visiting the main town, Karumba, between March and September 2006 were examined using the bootstrap method to estimate confidence intervals for mean tourist catch and harvest of grunter, Pomadasys kaakan (Cuvier), and other recreational target species. Tourist anglers harvested between 99.8 and 117 t of P. kaakan and 32.6–38.2 t of blue salmon, Eleutheronema tetradactylum (Shaw), during the survey period. Resident recreational anglers harvested an additional 15–35 t of P. kaakan, but very little E. tetradactylum. In comparison, commercial harvest was 19 t of P. kaakan and 64 t of E. tetradactylum in the whole of the Queensland section of the Gulf of Carpentaria. The results underscore the need for appropriately collected recreational fishing data to support integrated fisheries management at the bioregional scale, and in the case of angling‐based tourist destinations, underpin a diversification of the tourist product.     

Do recreational fisheries metrics vary on differently sized fishing grounds?

This study aimed to assess the relationship between basic metrics in recreational fishing and the size of the fishing ground. Data were obtained from individual angling logbooks collected by the Czech Fishing Union over 12 years on 212 fishing grounds located in the regions of Prague and Central Bohemia in the Czech Republic. Small fishing grounds had the highest catch, yield, numbers of fishing visits and numbers of angling guard controls per hectare. Medium‐sized fishing grounds had the highest catch, yield, and numbers of both fishing visits and angling guard controls per fishing ground. Anglers returned to medium‐sized fishing grounds most frequently. The percentage of anglers who caught and took home at least one fish decreased with increasing size of the fishing ground. In conclusion, basic metrics in recreational fishing are related to the size of the fishing ground, which thus plays an important role in fisheries management.     

Ice fishing reveals size structure but not abundance of Eurasian perch in small boreal lakes

Management of inland recreational fisheries would benefit from stock abundance and size structure data. Feasibly standardised angling methods such as ice fishing could produce representative catch-per-unit-effort (CPUE) information on the abundance of different-sized fish in small lakes. Here, we first used standard Nordic multimesh gillnets to obtain number-per-unit-effort (NPUE), biomass-per-unit-effort (BPUE) and size structure data on Eurasian perch (Perca fluviatilis) stocks in 11 small boreal lakes in summer. Second, the same lakes were ice-fished by voluntary anglers using a pre-defined, loosely standardised protocol to obtain angling-based NPUE, BPUE, and length frequency distributions. Effects of environmental variables such as water oxygen concentration and light penetration on angling catch rates were controlled statistically. Neither perch Nordic gillnet NPUE nor BPUE corresponded to ice-fishing CPUEs. However, the length distribution of the catch did not differ between methods. Our results imply that traditional ice fishing applying natural baits is relatively unselective for fish size and could produce valid length-based indicators for management purposes while angling CPUE was poorly related to Nordic gillnet CPUE.     

From scientific obscurity to conservation priority: Research on angler catch rates is the catalyst for saving the hump‐backed mahseer Tor remadevii from extinction

1. The mahseer (Tor spp.) fishes of South and Southeast Asia are iconic megafaunal species that are highly valued by recreational anglers. Knowledge on their populations is limited owing to the challenges associated with sampling these large‐bodied fishes (>50 kg) in remote monsoonal rivers.
2. Despite its global iconic status among recreational anglers, the hump‐backed mahseer of the Cauvery River (South India) lacked a valid scientific name and was on a trajectory towards extinction until its rapidly declining population status was established by analyses of angler catch records.
3. Angling records from 1998 to 2012 showed that mahseer catch rates had increased in this period. The resulting publication in Aquatic Conservation (AQC) highlighted the positive role of catch‐and‐release angling in providing information on data‐poor species. However, further analyses showed that these catches comprised not one but two distinct phenotypes.
4. Before 1993, all mahseer captured were hump‐backed; since then, a blue‐fin phenotype appeared in catches and subsequently dominated them. These results triggered further studies indicating that the hump‐backed mahseer was the endemic Tor remadevii and that the blue‐fin was the invasive Tor khudree, introduced in 1976 and then stocked periodically from hatcheries.
5. The initial AQC publication successfully demonstrated the high value of organized angling as a monitoring tool for data‐poor fishes and its application to assessing the temporal population patterns of large‐bodied fishes in monsoonal rivers. It was also the catalyst for initiating subsequent studies on T. remadevii that, together, enabled its recent assessment as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) Red List. In the absence of the AQC paper, and the subsequent studies that it triggered, it is highly probable that the species would have remained on a trajectory towards rapid extinction. Instead, the first major steps to safeguarding its future have been taken.

     

Reviving the unique potential of recreational fishers as environmental stewards of aquatic ecosystems

Recreational anglers have been key players in aquatic conservation, but this role is increasingly obscured. Other environmental sectors are now more visible stakeholders engaged with biodiversity. Recreational fishing has relevant environmental and moral implications, but these can be resolved via improved governance and management. More difficult is replacing the stewardship capacity provided by anglers. When analysed against a novel environmental stewardship framework based on place and identity, care, knowledge and agency, we find that marginalizing anglers could diminish aquatic biodiversity conservation. This outcome is likely because excellence in recreational fishing involves habituation of skills and ethical imperatives associated with sustainable and responsible use of fish populations. These dimensions are probably not so pertinent and correspondingly less developed in other nature stakeholders. Importantly, catching and killing wild animals catapults anglers into a food web and associated ecological conscience that most other outdoor activities cannot generate. As a result, recreational fishing often engenders feelings of care and responsibility for aquatic systems that support personal well-being, bridging the stewardship value-action gap through development of local assessment, management and evaluative competencies and associated agency. Transdisciplinary cooperation with scientists, managers and policymakers can unleash the stewardship potential of recreational anglers and engage their capacity for the common good.     

The use of European river lamprey as bait by the UK coarse predator angling community

Recreational fishing is a commonplace leisure activity within the developed world but can generate tension when activities conflict with conservation agendas. A potential conflict arises over the use of European river lamprey, Lampetra fluviatilis (L.), a protected species, by UK coarse (freshwater non-salmonid) predator anglers. This study used geographically stratified interviews with 69 predator anglers to explore attitudes towards the use of lamprey as bait, their conservation status and knowledge of biosecurity regulations. Most participants used lamprey as bait to some degree and agreed that, if threatened by exploitation, a ban on their use as angling bait should be implemented. Ordinal regression analysis indicated the presence of a subset of anglers who value lamprey as bait more than others and may oppose conservation efforts. The benefits of the potential establishment of bait certification schemes are also considered.