Assessing long-term changes to estuarine benthic communities in the northwestern Gulf of Mexico
In: Estuaries and Coasts. Estuarine Research Federation: Port Republic, Md.. ISSN 1559-2723; e-ISSN 1559-2731, meer
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| Auteurs | | Top |
- Williford, D.
- Anderson, J.
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| Abstract |
The assessment of long-term changes to estuarine biotic community structure is an important first step towards fisheries management and conservation in the face of changes to climate and other extrinsic factors. In Texas, temporal changes in community structure have recently been documented in several independent studies, but such studies are often focused on larger, managed pelagic species, rather than smaller benthic organisms. We used a 38-year (1986–2023) dataset of fishery-independent trawl data to assess spatial and temporal change to estuarine benthic fish and macro-invertebrate communities coast-wide across Texas. We observed significant spatial variability in catch-per-unit-effort (CPUE) that was associated with a known transition from northern (temperate) to southern (sub-tropical) climatic regimes. We also observed significant temporal variability between early (1986–2001) and more recent years (2002–2023), and this variability was associated with changes in overall CPUE, the ratio of pelagic/demersal taxa, Shannon diversity index, taxonomic distinctness, and either positive or negative impacts to annual CPUE of several commonly encountered taxa. Linear regression revealed that changes in community structure (modeled using an ordinated variable from principal components analysis) and community diversity metrics were significantly correlated with both a decline in commercial shrimping effort and an increase in the Atlantic Multidecadal Oscillation (AMO) index. Reduced shrimping effort has reduced bycatch mortality of trawl-associated fish species, many of which have also benefitted from milder winters associated with the warm phase of the AMO. Reduced fishing-related mortality of trawl-associated fish species combined with a warming climate have likely contributed to reorganization of benthic fish and macro-invertebrate communities over time. Our results indicate that climate factors are at least as important as fishing in shaping biotic communities of estuaries in the northwestern Gulf of Mexico, and both factors should be considered when devising management strategies for individual species and estuarine communities alike. |
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