The fish community of a newly restored southern California estuary: ecological perspective 3 years after restoration

Abstract

Bays and estuaries are considered essential fish habitat, yet in many parts of the world, these areas have been degraded or destroyed. In southern California, habitat restoration has become a widely used approach for protecting coastal ecosystems; however, there is little information available on the success of these efforts. Monthly abundance surveys were employed to examine spatial and temporal trends in the fish assemblages 3 years after the restoration of the Bolsa Chica Full Tidal Basin (BCFTB). This was used as a short-term success assessment of the BCFTB restoration, as well as an important baseline against which future studies can determine the long-term trajectory of the restoration. Forty-four species of fish were caught inside the BCFTB, at an average density of 116.8 fish 100 m−2 and an average biomass of 4.2 kg 100 m−2. There was a seasonal pattern in fish abundances but no overall increase or decrease in abundances during the entire study period. Marine, estuarine and migrant fish species were found in the BCFTB, each showing different seasonal patterns in abundance, similar to nearby estuaries, with 14 species driving these patterns. Water temperature and season were the most influential factors on the species composition of the fish community in the BCFTB. Therefore, 3 years after restoration the BCFTB is providing habitat for coastal fish species where none existed previously, and shows a community structure similar to natural estuaries in southern California. The BCFTB restoration has been initially successful but needs to be monitored periodically to assess its long-term success.