Baldisimo, J. G. P. | bioRxiv Science

bioRxiv2025

Anthropocene genetic diversity loss in the marine tropics

Genetic diversity is a crucial component of biodiversity, and as such, its maintenance and preservation is of high conservation concern. Tropical environments are undergoing intense rates of environmental change, and these changes may be driving large declines in genetic diversity. However, data on genetic diversity are highly skewed towards temperate regions. The degree to which diversity loss has occurred in tropical species, particularly marine species, remains an open and important question. Here, we directly compare genomic data from modern and museum collections of two commercially-harvested nearshore marine fishes (Equulites laterofenestra and Gazza minuta) gathered from a single location in the Philippines, spanning a century of intense environmental change. These data reveal a marked loss in genetic diversity and evidence for multiple orders of magnitude reductions in effective population size (Ne) in both species, indicating substantial genomic erosion. Such a decline highlights the long-lasting genomic consequences of anthropogenic activity and sheds light on an, until-now, invisible loss of diversity from the most biodiverse ocean region. Significance StatementRecent reports have shown that genetic diversity in marine fishes has declined either slightly or not at all during the Anthropocene. However, almost all studies investigating marine genetic diversity loss have been from temperate latitudes, whereas tropical marine environments experience some of the most intense human impacts. Here, we directly compare genomic data from modern and historical specimens of two commercially-harvested fishes from the Philippines. We show that marine species in the tropics have already lost substantial genetic diversity and may have undergone severe bottlenecks over the past century. These results shine a light on the previously invisible loss of genetic diversity in the most biodiverse region of the ocean, and they emphasize the evolutionary consequences of the Anthropocene.

ecology↗

bioRxiv2024

Evaluating Species at Risk in Data-Limited Fisheries: A Comprehensive Productivity-Susceptibility Analysis of the Most Traded Marine Aquarium Fish

The marine aquarium trade is a significant global industry harvesting millions of live coral reef fishes annually. Wild-caught fish dominate public and private aquaria markets in the USA and Europe, supporting fisher livelihoods in the Indo-Pacific. This diverse and species-rich trade is considered data-limited, creating barriers to quantify the sustainability of this fishery to the net benefit of the coral reef socio-ecological system. We present a revised and expanded productivity-susceptibility analysis (PSA) framework to assess the vulnerability to overharvesting of the top 258 traded species, an estimated 92.5% of all import volume into the USA in 2011. Vulnerability was calculated based on various productivity and susceptibility factors, tailored to the unique life-history and fishery selectivity characteristics of the marine aquarium trade. We present novel factors that improve model accuracy, methods to overcome missing data for individual factors, and apply an improved Gaussian mixture model clustering algorithm to objectively classify species as least, moderately, or most vulnerable. Our results show that an overwhelming 85% of species evaluated fall into the least or moderately vulnerable classification, with the remaining species designated as high priority for localized assessment and management initiatives. A comparative case study between our PSA and the popular FishBase Vulnerability assessment illustrates how it is ill-suited to handle data limitations of non-food fishes. The results of our PSA, at a species and family level, provide useful information to stakeholders and serves as a robust and accessible risk assessment tool to prioritize species for management based on their vulnerability scores.

ecology↗