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.

Sustainable management of recreational fisheries requires balancing angler attitudes and behaviour with fisheries' biological potential. Herein, we investigated the balance in the sea-run brown trout (Salmo trutta) fishery around the Swedish island of Gotland using data collected through a creel survey, test fishing, and spawning returns to selected streams. Anglers accurately anticipated catches of large fish but underestimated the role of natural reproduction in supporting the stock. Female sea trout entering spawning streams and post-spawn sea trout caught on the coast were significantly larger than spawning males and non-spawned fish, and were particularly important for the fishery. Larger sea trout also faced a higher level of harvest pressure than other sizes. Small changes to angler preferences, harvest rates, or regulations could significantly influence characteristics and sustainability of this fishery. The scale and direction of these changes merit further investigation.

Recreational angling for novel marine species and related tourism development can be important in a Blue Economy. The milkfish (Chanos chanos) is growing in popularity as a target of fly fishing-based catch-and-release (C&R) recreational fisheries, largely because of their challenge to catch and powerful swimming abilities, resulting in fight times that can exceed 1 h. Anecdotal sentiments by anglers claim that milkfish can fight for long periods of time because they do not accumulate blood lactate. To test this hypothesis, we measured blood lactate and blood glucose for 21 milkfish caught by fly fishing in the remote Alphonse Group of islands, Republic of Seychelles. Fight times ranged 5–78.3 min. Blood lactate and blood glucose concentrations increased with fight times that did not exceed 60 min. Total length of milkfish was not correlated to blood lactate or blood glucose concentrations. Ours is the first study on C&R of milkfish that debunks the anecdote that milkfish can fight for long periods of time because they do not accumulate blood lactate. Our study also revealed that milkfish may begin to physiologically recover after fight times longer than 60 min. In the context of C&R, our study indicates that anglers should limit fight times to 20–30 min when possible to reduce angling-induced physiological stress and other potential impacts (e.g., depredation) on milkfish in recreational fisheries.

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.