Southern California Abalones: Can Stocks Be Rebuilt Using Marine Harvest Refugia?

Abstract

Recovery of the isolated Palos Verdes Peninsula (PVP) kelp forest community after severe disturbance offers important implications for the design of marine harvest refugia. In 1977, part of the Southern California mainland coast was closed to abalone fishing to promote natural recovery. Pink (Haliotis corrugata) and green (Haliotis fulgens) abalones, historically the more abundant haliotids at PVP, did not respond. Nearby islands had substantial stocks, but the short planktonic period of green abalone larvae suggested that dispersal between isolated beds was uncommon. A drift tube study supported this hypothesis and stressed the importance of local brood stock. An experimental transplant of green abalone brood stock into sites where the drift tube data suggested high probability of larval retention led to a dramatic increase in juvenile abundance, a pattern not seen at distant controls. Other taxa with different distributions and larval periods further support the importance of dispersal potential to the natural recovery of depleted stocks. Thus, refugia design must consider the life history of target species, the oceanographic regime and distances from source areas, as well as the feasibility of enforcement.