Consistencies in the dietary and isotopic niche of spotted seatrout, Cynoscion nebulosus, across a salinity gradient within a coastal Louisiana estuary

Estuaries are essential habitats for recreational and commercial fish that are shaped by both natural and anthropogenic processes. In Louisiana a combination of climate change and planned coastal restoration actions is predicted to increase freshwater introduction to coastal estuaries. As such there...

Full description

Saved in:
Bibliographic Details
Published in:Journal of fish biology 2024-08, Vol.105 (2), p.459-471
Main Authors: MacRae, Pamela S. D., Russell, Micah, Cowan, James H., Fry, Brian, Moyo, Sydney, Polito, Michael J.
Format: Article
Language:English
Subjects:
Abundance
Animal morphology
Anthropogenic factors
Brackishwater environment
Brackishwater fishes
Climate change
Climate prediction
Coastal ecology
Coastal processes
Cynoscion nebulosus
Ecology
Estuaries
Estuarine dynamics
Estuarine fisheries
Fish
food webs
Freshwater
freshwater inputs
gut contents
Habitat changes
Habitats
Hydrogeochemistry
Inland water environment
Introduced species
Isotopes
Marine crustaceans
Niches
Relative abundance
Restoration
Salinity
Salinity effects
Salinity gradients
Spatial variations
Stable isotopes
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Estuaries are essential habitats for recreational and commercial fish that are shaped by both natural and anthropogenic processes. In Louisiana a combination of climate change and planned coastal restoration actions is predicted to increase freshwater introduction to coastal estuaries. As such there is a need to quantify the relationships between estuarine fish ecology and salinity to aid in predicting how species will respond to shifts in salinity. We investigated the relative abundance and dietary niches of adult (24.5 ± 5.4 cm standard length) spotted seatrout Cynoscion nebulosus across varying salinity regimes (oligohaline, mesohaline, and polyhaline) within Barataria Bay, Louisiana, using a combination of net sampling and gut content and stable isotopes analysis. We found that the relative abundance of C. nebulosus was lowest at the oligohaline site, translating to approximately five fewer fish captured for every single psu decrease in a site's average annual salinity. In contrast, we found that diets and, to a lesser extent, isotopic niches had a high degree of overlap across sites with differing salinity regimes. Fish and penaeid shrimp were the most common and important prey taxa recovered from guts at all sites. The small isotopic differences found among sites were likely due to spatial variation in hydrogeochemical baselines, and the observed isotopic overlap provides support for the idea that C. nebulosus move between adjacent salinity regimes and forage throughout Barataria Bay. Our results contribute to a greater understanding of the salinity preference and trophic ecology of C. nebulosus that can aid in predicting their responses to future salinity and habitat changes within Barataria Bay associated with predicted climate change and planned coastal restoration actions.
ISSN:0022-1112
1095-8649
1095-8649
DOI:10.1111/jfb.15810