Gulf deep-water species show genetic warning signs with differing trajectories
Genetic analyses of five deep-water species in the Gulf of Mexico found indicators of reduced long-term resilience. The peer-reviewed research examined three lanternfish and two shrimp species, drawing on samples collected over several years. Their trajectories varied: one fish lost about 8 percent of its genetic diversity, while other species showed recovery, temporary declines or comparatively stable patterns.
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Samples track fish and shrimp over several years
Five deep-water species in the Gulf of Mexico showed genetic indicators associated with conservation risk in a peer-reviewed study. Three lanternfish species and two shrimp species were investigated. Researchers combined newly generated sequences with earlier data; quality filtering left 486 individuals for analysis. The fish samples covered 2011–2023 and the shrimp samples 2015–2023.[1], [2]
Marine scientist Pedro A. Peres of Florida International University led the work from the Bracken-Grissom Lab. Co-author Heather Bracken-Grissom is assistant director of the university’s Institute of Environment Coastlines and Oceans Division. Keith Sellers, also at the university, and Tracey T. Sutton at Nova Southeastern University contributed to the study.[2]
Diversity follows different paths among species
Diaphus dumerilii, one of the lanternfishes, lost approximately 8 percent of its genetic diversity over more than a decade. The other species showed temporary losses, subsequent recovery or relatively little change. Estimates of effective population size, which describe transmission of genetic variation rather than directly counting animals, fell below commonly used long-term resilience thresholds in all five species. The thresholds’ applicability across species remains debated.[1]
Bracken-Grissom said genetic variation helps populations adjust to changing conditions, resist disease and recover after environmental disturbances. A loss of that variation can reduce their ability to withstand later pressures. The study’s measurements examine this inherited variation alongside the demographic estimates, providing a genetic account of the species’ condition over time.[2]
Habitat models project less favourable Gulf conditions
The population models indicated decreases but gave different timings and rates of change. Climate-based habitat models projected less suitable Gulf conditions for four species, with uncertainty particularly pronounced in distant and high-emission scenarios. Genetic records from before the Deepwater Horizon oil spill were insufficient to establish a direct causal link between that disaster and the observed changes. The largest projected habitat reduction cited by the university was 70 percent. Earlier investigations had recorded declines in deep-sea animal populations after the 2010 disaster. Peres said some populations may already have had genetic vulnerabilities before the spill. The researchers called for sustained genetic monitoring to be included in biodiversity assessments.[1], [2]
