Association between self-fertilization rates and the frequency of malformed larvae in farmed populations of the northern scallop Argopecten purpuratus (Lamarck, 1819)

Increased frequencies of malformations and the reduction of viability and fecundity are some of the first manifestations of inbreeding depression in animals. The northern scallop, Argopecten purpuratus (Lamarck, 1819), is a functional hermaphrodite species with partial self-fertilization. During artificial reproduction, this species may present high degrees of self-fertilization. In this work, the association between the selfing rate and the frequency of larval malformations and survival were analyzed. Mature adults were spawned, and female and male gametes were collected separately from the fifth or later spawning pulses. Oocytes were fertilized with sperm from another individual, forming families of complete siblings. Selfing rates were verified by the proportion of cleaving oocytes in a non-fertilized sample. Self-fertilization ranged from 0 to 100% among families, with a normal distribution. The proportion of malformed larvae was distributed randomly among the families analyzed, but was negatively correlated - moderately but significantly - with the selfing rate and the mean water temperature of the culture. These results suggest that self-fertilization in scallop families can favor greater homeostasis of larval development.