A COMPARISON OF LARVAL AND JUVENILE STAGES OF THE LOBSTERS Homarus americanus, Homarus gammarus, AND THEIR HYBRID1

Previous studies have shown that H. gammarus progeny are generally larger than those of H. americanus at all stages (Gruffydd et al., 1975; Van Olst et al., 1976). In addition, the 2 nephropid lobsters are known to be similar genetically (Hedgecock et al., 1977). Recently these 2 closely related species have been successfully hybridized. A comparison of the growth rates of the progeny from these crosses with the parental types was conducted. The larvae of the 3 varieties reached the post‐larval stage in approximately the same time, with no significant differences in survival. The H. gammarus and hybrid larvae were larger than the H. americanus larvae. A comparison of growth and survival for one year of culture showed no significant differences in the size attained by juveniles of the 2 lobster species or by their hybrids. Variation in morphological characters, pigmentation patterns, and behavior are discussed. Biochemical analyses of pereiopod tissue were performed to verify the pedigree of the hybrid progeny.