Effects of Estuary-Wide Seagrass Loss on Fish Populations

Globally, habitat loss in coastal marine systems is a major driver of species decline, and estuaries are particularly susceptible to loss. Along the United States Pacific coast, monospecific eelgrass (Zostera marina) beds form estuarine vegetated habitat. In Morro Bay, California, experienced an unprecedented decline > 95%, from 139 ha 2007 < 6 by 2017. Fish populations were compared before after using trawl surveys. Beach seines surveys also conducted during post-decline period characterize within outside remnant beds. While estuary-wide did not result fewer fish or less biomass, it led changes composition. The post-eelgrass was characterized increases flatfish (mainly Citharichthys stigmaeus) staghorn sculpin (Leptocottus armatus), decreases specialists including bay pipefish (Syngnathus leptorhynchus) shiner perch (Cymatogaster aggregata). There similar trends inside patches. These findings support evidence across multiple ecosystems suggesting that predominance habitat-specialists predicts whether leads overall abundance. addition, critical habitats seascapes can restrict population connectivity lead range contraction. For pipefish, Bay likely create biogeographic divide. Currently, dominated sculpins, longevity this new ecosystem state will depend on future recovery dynamics supported ecosystem-based management approaches.