Fisheries Management and Ecology最新文献

Hundreds of Fisheries Local Action Groups (FLAGs) have emerged along the European Union coast trying to dynamize fisheries-dependent areas through an approach based on community-led local development (CLLD) strategies. In this research, we characterized and analyzed environmental projects funded by the FLAGs through the European Maritime and Fisheries Fund in Spain from 2014 to 2020. The Spanish Network of Fisheries Groups database allowed us to locate projects defined as environmental, which were then classified into six areas and different project typologies. Most projects were categorized by FLAGs as environmental but were really linked to tourism development. Moreover, true environmental projects were substantially lower in total cost than statistics showed. These conclusions should lead to a reflection on the role that FLAGs and European fisheries funds should play in environmental care of European coasts.

The impact of recreational fisheries on marine ecosystems is often overshadowed by commercial fisheries, although recreational fishing harvest can be substantial, especially for species that are either overfished or experiencing overfishing. Delaware is a small coastal state with ~1,000,000 residents and nearly 272,000 resident and non-resident anglers. We used publicly available data for Delaware's recreational fisheries during 1981–2021 to determine the nine most caught fish species and to evaluate trends in total numbers caught, harvested, released, and catch per unit effort (CPUE). The top nine most frequently captured fish by recreational anglers were Summer Flounder (Paralichthys dentatus), Atlantic Croaker (Micropogonias undulatus), Bluefish (Pomatomus saltatrix), Black Sea Bass (Centropristis striata), Weakfish (Cynoscion regalis), White Perch (Morone americana), Tautog (Tautoga onitis), Striped Bass (Morone saxatilis), and Spot (Leiostomus xanthurus). The proportion of fish released increased through time for all nine species, suggesting that the recreational fishery in Delaware is transitioning from a harvest-oriented to a catch-and-release-oriented fishery. Observations of higher release rates in recreational fisheries of Delaware are consistent with the findings elsewhere in the world for freshwater and marine systems.

Quantifying the population dynamics of marine species is difficult when good, comprehensive data are not available. We sought to determine if the kingfish Scomberomorus commerson stock in the Persian Gulf was overfished. The ICES data-limited assessment framework was used to provide precautionary advice, with a 20% decrease advised in situations where only catch or bycatch data were available. The length-based Bayesian biomass (LBB) was used to model fork length from landing records of licensed fishers in the Khuzestan Province during 2002–2018, which had increased despite sought being overexploited. Most kingfish were immature and smaller than optimum length of the catch (L_c-opt = 88 cm) and optimum length (L_opt = 104 cm). Relative biomass (B/B_msy) ranged 0.62–0.66 and exceeded 0.5. The B/B_msy ratio (1.25) was >1.1. The stock appeared to be healthy and exploitable, but wide confidence intervals of the B/B_msy ratio complicated interpretation of stock status. The kingfish stock appeared to use waters of the study area as a spawning and nursery ground, so many young immature individuals were present. If current exploitation of young individuals continues, this the stock will eventually be overfished. Long-term increases in the catch of young immature kingfish can have a side effect on stock maturation and recruitment. We recommend that the mesh size of fishing gear be selected based on optimum length, to enhance economic, and commercial viability of the kingfish fishery.

Krillscan software was developed to automatically process echosounder data and achieve an accelerated and transparent analysis of backscatter data that allows calculation of target biomass. Herein, the fishery for Antarctic krill (Euphausia superba, Henceforth Krill) was used as a case study to develop the approach. Implementation of a sustainable management strategy for the krill fishery is complicated by a lack of regularly updated krill abundance data on spatiotemporal scales of the fishery. To increase krill biomass data availability, automatic echosounder data processing and swarm detection software was tested against traditional manual scrutinization with LSSS software and agreed with only minor offsets in estimated nautical area scattering coefficients. In addition to automatic processing and data transfer, Krillscan also has a graphical user interface to supervise automatic krill swarm detection. Echogram size can be compressed up to 100 times and raw data are processed faster than generated, thereby enabling near-real time analysis and data transfer. Compressed data can be transmitted online to allow fishing vessels to conduct surveys without having scientific personnel with special expertise on board.

Sterlet (Acipenser ruthenus), one of the last sturgeons in the Danube basin, is regularly stocked in national and international restoration programs, but the efficacy of stocking has not yet been evaluated. Effectiveness of stocking should involve marking and evaluating growth and survival of juveniles. Chemical marking with alizarin red S (ARS) was evaluated to establish optimal ARS staining approaches for juvenile sterlet. Bathing in a 100–200 mg l⁻¹ ARS concentration for 12 h had no affect on fish mortality or growth. Use of a green laser on the upper five external structures (dorsal, lateral, and ventral scutes and rostral and anal plates) allowed easy detection for at least a year. Simultaneous use of multiple external structures was effective for distinguishing stocked from wild fish without harm or sacrifice. We conclude that ARS staining enabled a cost-effective, quick, and labour-nonintensive way to mark sterlet, with a high-field detectability and minimal previous experience required.

The Mekong River is the most productive inland fishery in the world and identified as a valuable source of hydropower generation. Consequently, benefits of energy production must be traded off against impacts on other ecological and environmental services, especially on fisheries that have been largely downplayed. We surveyed fish markets in 12 provinces in the Lower Mekong River Basin (LMB) to quantify the diversity, abundance and prices of fish species and to account for potential impacts of water infrastructure and development projects. Of 116 species in nine major ecological guilds in markets, potamodromous main channel spawners were the most diverse guild that contributed 30% of species and were present in markets in all countries and sites, whereas anadromous species were the least diverse guild with two species in Vietnam only. More than 45% of fish recorded in local markets in Cambodia and more than 80% in Vietnam were small-sized fish (<25 cm), whereas about 50% of fish marketed in Lao PDR and Thailand were large-sized fish (>50 cm). Fish were sold by both size and species, with most species sold in only one size category. The first-sale price was highest in Lao PDR, followed by Thailand, Vietnam and Cambodia. Our findings provide primary ecological and economic information that can be used to estimate potential economic losses of fisheries when considering trade-offs between energy and the environment.