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To avoid the spread and environmental impacts of the European catfish (Silurus glanis), which arrived in Portugal around 2006, it is fundamental to understand anglers’ behaviors and perceptions. To address this need, 339 Portuguese anglers were surveyed online and face-to-face and divided into two groups (catfish anglers, n = 115; and non-catfish anglers, n = 224). The majority of surveyed anglers were males (>95%) who consider that catfish is not beneficial to the development of angling (>62%) and acknowledge its negative impact on other fish species (>84%), mainly by predation (>89%). Catfish anglers perceive the species as more positive for angling and for other fish species. Principal Component Analysis showed that anglers’ behaviors are mainly driven by their awareness of the impacts of European catfish and by their angling experience. Regression modeling inferred the probabilities of two anglers’ behavior (targeting catfish and practice of catch and release) and one perception (catfish is beneficial to angling), which are considered promoters of catfish invasion, and detected strong correlations among these three variables. Therefore, it is strongly advised to implement an educational and law enforcement program to stop illegal practices that promote the dissemination of invasive fish species like European catfish.

California (USA) recreational fisheries are biologically and economically important, and depend heavily on demersal fish species, especially during winter and spring months. While many of these species have shown signs of population decline, the size-selective nature of fishing generally impacts population size structure before population declines are evident. However, long-term size-specific information, especially for the largest size classes, is rare. Our ability to gain an early warning of fishery overexploitation is thus limited. We developed the Western Outdoor News (WON) database, which consists of a long-term (1966–2013) time series of trophy-sized fishes caught along the California coast and Baja California, Mexico. Sixteen demersal species, with a total of 25 943 records, were the focus of this study. Twelve of the 16 species showed signs of long-term decline in trophy size, but 9 of these 12 showed signs of transition to either stabilization or initial recovery in the most recent years. The more progressive state fisheries management actions adopted since 2001 have likely contributed to this apparent shift in trends, and the new coastal marine protected area (MPA) networks may benefit these populations even more in the future. Trophy size increased with distance from home port, and the distance required to reach maximum trophy sizes increased over time, especially for the rockfishes, which suggests that declines were due to overfishing. Trophy sizes of fishes caught specifically within the Northern Channel Islands region showed long-term declines through the early 2000s, but also showed signs of stabilization or initial recovery for some species since the 2003 implementation of the Northern Channel Islands network of MPAs.

In a commercial fishery, some fish are classified as low-value, but their classification varies in different countries. The aim of this study was to determine the abundance, contribution, and dominance of low-value fish species, such as Abramis brama < 1000 g, Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis < 100 g, Rutilus rutilus < 200 g, and Scardinius erythrophthalmus < 200 g, in 145 Polish lakes of different areas, depths, and trophic statuses situated in the northern and central parts of Poland in 2021. Perca fluviatilis and R. rutilus were the most frequent low-value species (100% and 99%, respectively). The contribution of all low-value fish to the total biomass of caught fish was relatively high, ranging from 37% in the mesotrophic lake to 100% in the eutrophic lake (mean of 77 ± 14%). Lakes in which the contribution of low-value species exceeded 90% were relatively numerous (24 lakes, 17% of the studied lakes). Among a total of about 437.5 thousand low-value fish, 261 thousand specimens (60%) had a body weight of below 10 g. All low-value fish species, except for P. fluviatilis and S. erythrophthalmus, were related to the studied environmental variables. The relative biomass of these species increased with increasing lake productivity, while it decreased with the increasing maximum and mean depth of the studied lakes. The high contribution of low-value fish to the total biomass in many lakes indicates the need for the constant monitoring of the abundance and structure of fish communities and the use of appropriate actions (biomanipulation and stocking with piscivorous fish species) to improve the ecological condition of lakes.

Shifting baselines, whereby people’s perceptions of what was the “natural” state of the environment changes with each generation, hinders conservation, restoration, and management. Formal and informal historical animal records can be used to inform past biological, ecological, and environmental patterns and processes. Trophy specimens are cultural and social objects but also are examples of informal historical records that may supply biological tissue and supplement formal natural history collections. The use of social media to gather information from citizen scientists has great potential for data collection of such specimens. The aim of this study was to evaluate the potential utility of Facebook and traditional media to collect data on taxidermal Murray cod (Maccullochella peelii), a large, long-lived freshwater fish endemic to the Murray-Darling Basin, Australia. A Facebook group, “Cod Spot,” was established as the location for information dissemination to potential citizen scientists, and where data on Murray cod mounts could be uploaded. This was complemented with social and mainstream media promotion, a research website, and an e-survey. Cod Spot received >7,000 interactions and approximately 400 participants. A total of 189 verified locations of Murray cod head and whole mounts were found. The e-survey provided verification of the potential to turn these cultural and social objects into ones with scientific value. Participants included interested persons, collectors, taxidermists, stewards, or owners of mounts. Most participants were males aged 35+, although women comprised almost a third of website users. This research has shown that low-cost marketing, combined with a widely dispersed, relatively common and well-known object of interest, can be effective at gaining participation in citizen science collaborations.

Global warming, eutrophication, fisheries overexploitation, species invasions, and habitat loss are the major threats to freshwater biodiversity. The aim of this study was to determine the species richness and diversity of fish in 535 Polish lakes of different morphometry (area of more than 50 ha and a maximum depth ranging from 0.4 to 108.5 m) and trophic status (from oligotrophy to hypereutrophy). A total of 39 fish species were found in the studied lakes, among which eight species were alien invasive. The Shannon diversity index varied between 0 and 2.04.The most common and frequent species were Rutilus rutilus (99.8% frequency) and Perca fluviatilis (99.6% frequency). Ten fish species, including five alien ones, were characterized by a very low frequency (<1%). The number of fish species in single lakes ranged from 1 to 19. In most of the studied lakes, 11 and 12 species (104 and 108 lakes, respectively) were caught. The richest taxonomic composition (19 species) was recorded in the meso-eutrophic lake with an area of 80 ha and a maximum depth of 34.4 m, slightly poorer (18 species) in the hypereutrophic lake with an area of 168 ha and a maximum depth of 2.7 m. The poorest taxonomic composition (one species) was found in a lake with low conductivity and circumneutral pH. Statistical analysis showed that the number of fish species decreased with increasing eutrophication conditions of the studied lakes, while it increased with an increasing area and the maximum depth of these lakes.

Hunting directly impacts the population dynamics of ungulates and can have a significant effect on the quality of phenotypic traits such as horns or antlers. In Poland, following a demographic collapse in the 1990s and the introduction of a hunting ban in 2001, the population of moose (Alces alces) has increased from 1,800 to over 20,000 individuals, recolonising its former range. As the moose is a charismatic species and a popular subject for nature photography, we analysed changes in antler size and shape in this cervid between 2005 and 2021 based on photos of male moose and antler casts provided by photographers or available in social media. Our findings indicate that during the hunting ban, the probability of observing the cervina antler type significantly decreased over time, from 47% in 2012 to 28% in 2021. Meanwhile, the probability of observing the intermediate and palmate antler types significantly increased from 44 to 53% and from 9 to 19%, respectively. The mean number of tines significantly increased from 3.2 in 2005 to 4.7 in 2021, and the antler size index significantly increased from 3.4 to 3.9. The most likely mechanism behind the observed changes could be the ageing of a population released from hunting pressure. We also observed regional variation in antler size, which is likely related to differences in environmental conditions. Our study serves as an example of how passive citizen science can contribute to our understanding of ecological trends and the quantification of population patterns. It also has important implications for management of species affected by trophy hunting.

The legal subsistence hunting scheme (resident hunting) in Tanzania was temporarily banned in 2015 because it was considered ineffective. So far, no attempt has been made to understand the challenges facing the scheme, especially from the hunters’ perspective. This study used 8 hunter focus groups (in total, 73 hunters) and 26 key informants in the Ugalla ecosystem of western Tanzania–from June to September, 2017–to determine the challenges faced by the resident hunting scheme before the ban, and the areas of the scheme that participants felt required improvement. Focus group discussions and key informant interviews were digitally recorded. In general, study participants perceived that resident hunting regulations were poorly enforced, leading to a number of incidents such as the killing of unauthorized game, hunting outside specified areas, false reporting of animals killed, and overshooting of quotas. They noted that hunting areas were under pressure from poaching, and encroachment by pastoralists and subsistence farmers. Conflicts over hunting areas and hunting rights between resident and trophy hunters were common. Participants recommended capacity strengthening to effectively administer resident hunting, through ensuring availability of human and financial resources. They perceived active hunter engagement as the best way to deal with poaching and non-compliant behaviour by hunters. Measures to guarantee coexistence between resident and trophy hunters were recommended, for example, a thorough review of hunting area boundaries to minimize hunting area conflicts. Further study should consider the impact of hunting on wildlife in hunting areas in relation to the issues reported in this study.

The influence of human harvest on evolution of secondary sexual characteristics has implications for sustainable management of wildlife populations. The phenotypic consequences of selectively removing males with large horns or antlers from ungulate populations have been a topic of heightened concern in recent years. Harvest can affect size of horn‐like structures in two ways: (a) shifting age structure toward younger age classes, which can reduce the mean size of horn‐like structures, or (b) selecting against genes that produce large, fast‐growing males. We evaluated effects of age, climatic and forage conditions, and metrics of harvest on horn size and growth of mountain sheep (Ovis canadensis ssp.) in 72 hunt areas across North America from 1981 to 2016. In 50% of hunt areas, changes in mean horn size during the study period were related to changes in age structure of harvested sheep. Environmental conditions explained directional changes in horn growth in 28% of hunt areas, 7% of which did not exhibit change before accounting for effects of the environment. After accounting for age and environment, horn size of mountain sheep was stable or increasing in the majority (~78%) of hunt areas. Age‐specific horn size declined in 44% of hunt areas where harvest was regulated solely by morphological criteria, which supports the notion that harvest practices that are simultaneously selective and intensive might lead to changes in horn growth. Nevertheless, phenotypic consequences are not a foregone conclusion in the face of selective harvest; over half of the hunt areas with highly selective and intensive harvest did not exhibit age‐specific declines in horn size. Our results demonstrate that while harvest regimes are an important consideration, horn growth of harvested male mountain sheep has remained largely stable, indicating that changes in horn growth patterns are an unlikely consequence of harvest across most of North America.

There is a large demand for bear parts in the Czech Republic, and this drives legal and illegal trade in various bear species sourced from outside the country. From 2010 to 2018, the Czech Republic reported legal imports of 495 bear parts, mostly as trophies from Canada and Russia. Illegal trade in bear parts and derivatives for medicine as well as trophies persists as evidenced by the number of seizures made by the Czech Environmental Inspectorate during this same period. From January 2005 to February 2020, 36 seizures involving bears, their parts and derivatives, were made totalling 346 items. Most cases involved trophies (skins, skulls, taxidermies) predominantly from Canada, Russia and the USA, followed by traditional medicines claiming to contain bear parts mostly from Vietnam and China. Three cases involved souvenirs or jewellery, and one case involved live bear cubs. The greatest number of seizures made originated from Vietnam, followed by Canada and Russia. As all countries involved in these incidents are Parties to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), there is a mechanism in place to jointly tackle this illegal trade. International collaboration is essential if efforts to end the illegal international trade in bear parts and derivatives are to succeed.

Effective fisheries management requires an understanding of human dimensions. This study elicited the salient motivations for recreational blue swimmer crab and black bream fishing in Western Australia and whether these views differed depending on the fishing location and/or the characteristics of the fisher. Crab fishers were strongly consumption-orientated and aimed to “catch big crabs” and “catch enough crabs to eat”. Furthermore, 91% consumed their catch, with only 2% practicing catch-and-release fishing. In contrast, 81% of black bream fishers did so for the sport/challenge, with the strongest motivation being to catch a bream considerably above legal size and with food only selected by 15% of respondents; most fishers released caught fish. The marked differences between the fisheries for the two species, which co-occur in the same estuaries, are likely driven by the accessible nature of the crab fishery, ease of catching crabs, the low cost of fishing equipment, and their taste. Fishing for black bream, however, requires more expensive equipment, patience, and a greater skill level. Fishers considered crabbing to be as important as other fishing and outdoor activities, whereas bream fishers considered bream fishing considerably more important, reflecting the trophy nature of this fishery.