Fish and Fisheries最新文献

Democratic regression is occurring around the world at precisely the time when progress on sustainable development and biodiversity conservation has become essential. To understand the extent to which democratic regression overlaps with (and therefore might be an issue for) marine fisheries, we examine the democracy trends of (i) key fishing states and (ii) key intergovernmental institutions. To do so, we use landings statistics published by the FAO and democracy measurements published by the Economist Intelligence Unit. Our findings suggest that democratic regression is indeed occurring in many critical marine fisheries actors and institutions and therefore represents an important challenge requiring close attention from resource managers, resource users, environmental governance researchers, and stakeholder and rightsholder groups. We outline a series of research themes and questions whose answers could strengthen the understanding of the nature and implications of democratic regression for marine fisheries.

Quantifying broad-scale population trends and distribution change is critical for effective management and conservation of marine species, particularly under climate change. However, fragmented regional survey data often hinder such efforts for transboundary populations. A prime example is Pacific Spiny Dogfish (Squalus suckleyi, Squalidae), a small shark with a remarkably slow life history and wide-ranging distribution. Dogfish are now caught incidentally but were heavily fished along the Pacific US–Canada coast ≈80 years ago. Reports on local population trends have conflicted along the coast, suggesting that movement between regions may be responsible. We fit spatiotemporal models integrating data from 10 surveys to synthesise trends in biomass, abundance, distribution and thermal niche for dogfish across their entire eastern Pacific Ocean range. Prior to 2003, Alaskan biomass increased through the 1990s whereas California to British Columbia indices were variable and imprecise. However, during 2003–2023, we found a coastwide 51% (95% CI: 38%–61%) decline in dogfish biomass with mature females and immature dogfish showing the largest proportional declines. Regionally, declines were steepest for the US West Coast (71%–85%) and Canada (58%–82%), while Alaska showed less severe declines (13%–54%). Off the US West Coast, dogfish shifted into deeper waters as temperatures in their habitat increased, but these patterns do not explain the coastwide declines. Our results suggest population declines are primarily driven by reduced abundance rather than between-region movement, indicating elevated coastwide conservation concern and helping focus investigations of causal mechanisms.

The spread and establishment of Amazonian species outside their native ranges through activities such as sport fishing, aquaculture, and the ornamental fish industry may lead to ecological changes in recipient ecosystems. We investigated the global distribution of Amazonian freshwater fish (AFF) and conducted a case study in the upper Paraná River Basin to assess potential impacts on fish fauna. We compiled a comprehensive dataset from multiple sources: global occurrence records from the Global Biodiversity Information Facility between 1980 and June 2024, and long-term fish fauna monitoring data collected from 1992 to 2015 across four reservoirs in the upper Paraná Basin. Global occurrences were aggregated into country-level distribution polygons to estimate species richness per nation, while records from the United States were analysed within freshwater ecoregion boundaries to highlight regions of high invasion risk. In the upper Paraná case, AFF presence was determined using a presence-absence matrix, and temporal trends in richness and proportion were analysed using linear and non-linear models. Our results, based on 76,796 records of 281 AFF species, reveal a marked increase in AFF occurrences outside the Amazon Basin, particularly in South America and the United States. In the upper Paraná River Basin, AFF richness increased until approximately 2005, while the proportion continued to rise throughout the study period. These findings support “Amazonization” as an emerging pattern with implications for native biodiversity and ecosystem functioning. This study underscores the need for targeted management strategies to mitigate the impacts of AFF introductions in freshwater environments worldwide.

Climate change is increasingly recognised as a critical threat to global biodiversity, yet its impacts on reproductive processes remain poorly understood in many marine taxa. Elasmobranchs (sharks, skates and rays) represent a particularly vulnerable group due to their peculiar life histories, low fecundity, and diverse reproductive modes. In this review, we synthesise current knowledge on how rising ocean temperatures may affect elasmobranch fertility across key stages of the reproductive cycle, including gametogenesis, mate searching, sperm storage, fertilisation, embryonic development, and offspring production. Evidence from 88 species suggests that thermal stress could impair sperm and oocyte quality, disrupt reproductive timing, alter embryonic growth and survival, and potentially exacerbate sexual conflict. While some reproductive strategies such as embryonic diapause, sperm storage, or behavioural thermoregulation may provide short-term buffering capacity, their effectiveness under rapid and sustained warming remains uncertain. We further highlight the macroevolutionary significance of elasmobranch reproductive diversity, as well as the conservation implications of fertility constraints under global change. Addressing these knowledge gaps is essential to refining demographic models, improving extinction risk assessments, and guiding the design of climate-resilient management strategies, including fisheries regulations and marine protected areas. By explicitly linking reproductive biology with conservation policy, we argue that understanding thermal fertility limits is key to predicting elasmobranch population trajectories in a warming ocean.

With novel ocean conditions rapidly appearing as the result of climate change, basing decisions about fisheries and other ocean activities on historical conditions is no longer tenable. There is instead a widespread need for shifting ecological baselines to more effectively guide decisions into the future. What has not been as widely recognised is that the relevant timescales differ substantially across ocean-related decisions, from lead times of hours to decades depending on the decision being made, and that this range necessitates a matching range of ecological forecast products across similar timescales. At the moment, a predictability gap exists at intermediate timescales, from multi-annual to multi-decadal forecasts. Because most fisheries and many other ocean activities rely on biological conditions like fish abundance or distribution, the ecological inertia of organismal growth, generational turnover, movement, and food web dynamics can help push ecological forecasts further across this gap. To realise this potential for more effective and usable ecological forecasts, coordinated research and implementation at the intersection of biology, climate science, social science, and decision-making is needed. These efforts will be critical for forecasting shifting ecosystem baselines and sustaining fisheries, ocean ecosystems, and the ocean economy in the coming decades of rapid change.