Intraspecific variation in reproductive potential with maternal body size in Gulf killifish Fundulus grandis

Gulf killifish Fundulus grandis show promise for commercial development as a baitfish species marketed to anglers on the U.S. Gulf Coast. Additionally, fishes in the genus Fundulus are increasingly cultured as model organisms for various fields of scientific inquiry. Research examining effects of maternal body size on reproduction in this genus and more generally in fractional spawning species with eggs capable of terrestrial development is lacking. The present study assessed the effects of female body size on reproductive investment in laboratory held Gulf killifish as well as subsequent implications for larvae. Larger females had significantly higher fecundity and produced individual eggs of greater volume. Gonadosomatic index more than doubled as female body mass increased from 6.9 to 12.9 g, but did not increase significantly in females of body mass > 12.9 g. Larger eggs required significantly longer incubation periods, and newly hatched larvae from larger eggs had more endogenous nutritional resources but shorter body length. Experimental results describe maternal effects in a fractional spawning species producing eggs with the ability to incubate terrestrially. Results also provide practically useful information for aquaculturists as F. grandis are increasingly cultured commercially and in laboratory settings.

► We examine reproduction in a fish species of commercial and scientific importance.
► We establish maternal effects on fecundity, egg size, and larval morphometrics.
► Egg size, time to hatch, and larval morphometrics show an unexpected relationship.
► A practical body size recommendation for female broodfish is generated.
► We postulate an association between egg size and terrestrial incubation in fishes.