Turbidity influences trophic interactions in estuaries

We investigated how changes in abiotic conditions resulting from human activities indirectly alter trophic interactions using turbidity in estuaries as a model system. Development and nutrient input are causing turbidity to increase in many coastal areas. Using an 18 yr data set from Aransas and San Antonio Bays in Texas, we found fish abundance (Sciaenops ocellatus, Pogonias cromis, Archosargus probatocephalus) to be highest in low turbidity ( 30 NTU; p 30 NTU). Predation on oyster spat was not different between low- and high-turbidity sites (p = 0.64). However, oysters devoted more resources to shell growth (p < 0.01) at a cost of less somatic growth and fecundity, a reaction known to occur in response to crab predators. Elevated turbidity can alter trophic interactions in estuaries by altering species composition and trophic interactions, leading to an increase in crab abundance, which can alter predation rates as well as growth in juvenile oysters