MEPS 211:205-213 (2001)  -  doi:10.3354/meps211205

ABSTRACT: A series of laboratory experiments was conducted to determine fertilization success in the commercial abalone Haliotis tuberculata L. Fertilization success is a function of sperm dilution, sperm-egg ratio, gamete age and the amount of time sperm and eggs are in contact. Sperm density required for optimum fertilization success in vivo, using 10 ml culture volume, was in the range 5 x 10⁴ to 5 x 10⁵ sperm ml^-1. When these experiments were repeated using 500 ml culture volume, results showed high levels of fertilization success across a far larger range of sperm dilutions with success >80% at 10³ sperm ml^-1. Sperm-egg ratios of >100:1 have little effect on fertilization success, but below these levels this factor becomes significant. Viability of both sperm and eggs decreased with age so that no fertilization occurred after 2.5 h. Maximum fertilization success occurred after 30 min sperm-egg contact time. These data suggest that sperm limitation may severely compromise reproductive success in exploited populations of H. tuberculata.

KEY WORDS: Fertilization success · Abalone · Haliotis tuberculata · Allee effect