Reproductive Potential Can Predict Recruitment Rates in Abalone

Abstract

In many marine invertebrates, the relationship between egg production and/or number of competent larvae and subsequent recruitment is often unknown. Estimating such relationship is critical for informing the management and conservation of exploited species because it determines a natural population's response to exploitation. In the current study, recruitment rates of abalone Haliotis fulgens and Haliotis corrugata were recorded by means of postlarval collectors inside and outside 2 marine reserves in 2 subsequent years. At the same time and locations, theoretical reproductive outputs were computed by combining estimates of abalone densities and size structure with literature data on size-dependent fecundity and size at sexual maturity. We found that observed settlement rates correlated positively and significantly with estimated reproductive output, suggesting that greater production of eggs by large and fecund individuals can result in predictably high recruitment rates. In addition, the slope of the linear relationship suggests that the proportion of eggs that settle and metamorphose to become postlarvae is between 0.2% and 0.3%. Although affected by great uncertainty, this value constitutes a unique estimate of larval survival for the genus Haliotis in a natural environment.