Relationship between over-crowding within egg capsules of the marine gastropod Acanthina monodon and prospects for juvenile success

Encapsulated development with extraembryonic yolk may lead to competition for nutrients within egg capsules. In this research, different degrees of competition among embryos in subtidal egg capsules of Acanthina monodon resulted in considerable differences in hatching size. For newly hatched juveniles, individuals hatching from less crowded egg capsules showed better survival, larger SL, higher rates of oxygen consumption, and higher rates of food consumption. However, by 28 days after hatching, the largest surviving juveniles were the best-performing individuals, regardless of the initial embryo density within the capsules. In summary, more crowded egg capsules resulted in poorer survival. These findings may help to explain the variability seen in juvenile success in some field populations; much of that variation may reflect stressful experiences that the new recruits have had during the early stages of their encapsulated development. •Acanthina monodon deposits a wide range of embryos per capsule.•At hatching, more crowded capsules released smaller and less heavyjuveniles•Growth, oxygen consumption, and ingestion rates were lower for juveniles hatching from more crowded capsules.•Juveniles emerging from crowded egg capsules showed post-hatching latent effects, with higher mortality for the smaller juveniles.