Hubbs-SeaWorld Research Institute, in partnership with the Coastal Conservation Association – California, operates a network of pre-release acclimation cages for a white seabass (Atractoscion nobilis) replenishment program in California. The acclimation cages are dispersed in embayments or nearshore in the southern California bight and most are operated by volunteers. Growout of seabass is conducted under the direction and authority of the California Department of Fish and Wildlife (DFW) as part of the Ocean Resources Enhancement and Hatchery Program. White seabass are spawned and reared in a marine fish hatchery using intensive recirculating systems for the first four months before they are transported to the volunteer cages. Mandatory DFW health inspections are conducted prior to their delivery and release from these cages. Fish are held in these acclimation cages for two weeks up to seven months in order reach a target size of 20 – 30 cm (8-12”) in length. All fish released from this program have an internal identification tag implanted in their cheek musculature. Fish are normally released at the cage site but some have occasionally been transported by boat to nearshore sites for release. We have demonstrated that these acclimation cages improve post-release survival by two-fold which has eliminated direct releases from the hatchery.
Volunteer growout cage operators are provided with a procedures manual that details their responsibilities including daily husbandry duties. A Growout Coordinator helps to manage pertinent activities among the various cages and serves as a conduit to DFW. Over the course of 30 years, stocking and operational practices have been customized for each facility based on a variety of factors including volunteer support levels, water depth, general water quality, proximity or activity of potential predators, and interactive effects with seasons. Here we report on contemporary practices and outcomes of these acclimation cages.