Subtidal Fish Habitat in a Temperate Lagoonal Estuary: Comparison of Salt Marsh Creeks, Sand, and Seagrass

Temperate lagoonal estuaries contain a mosaic of subtidal habitats including salt marsh creeks, sand, and seagrass. Studies comparing fish use of estuarine habitats have focused disproportionately on sand and seagrass habitats, and along the U.S. east coast, previous studies that have made the direct comparison between subtidal salt marsh creeks, sand, and seagrass habitats were spatially narrow in scope. Here, we performed a comprehensive comparison of fish species composition, abundance, diversity, richness, and fish lengths across subtidal salt marsh creek (upper creek and creek mouth sites), sand, and seagrass habitats within a temperate lagoonal estuary. Daytime otter trawl sampling occurred at 45 sites within Barnegat Bay (New Jersey) in April, June, August, and October during 2012-2014. Seventy species representing estuarine transients, residents, southern strays, and shelf strays were observed, and juvenile and small adult fishes dominated the collections. There were some differences in species composition between habitats, with the assemblages in upper creek and seagrass habitats being the most dissimilar. Fish abundance, diversity, and richness were often higher in creek mouth and seagrass habitats than in sand habitat. Similar to seagrass habitats, creek mouths were shallow, more saline, and contained complex physical structure (macroalgae, marsh banks). Many fishes used all habitats (e.g., bay anchovy Anchoa mitchilli), but others were partial to certain habitats (e.g., fourspine stickleback Apeltes quadracus in seagrass). This study reaffirmed that many interacting factors shape fish assemblages and demonstrated the significance of marsh creeks to the subtidal habitat mosaic of this temperate lagoonal estuary.

Automated summary

This study conducted a comprehensive comparison of fish species composition, abundance, diversity, richness, and fish lengths in subtidal salt marsh creek, sand, and seagrass habitats within a temperate lagoonal estuary. The results showed that fish abundance, diversity, and richness were often higher in creek mouth and seagrass habitats than in sand habitat, and there were some differences in species composition between habitats. The study emphasized the significance of marsh creeks in shaping the subtidal habitat mosaic of temperate lagoonal estuaries.