Effect of substrate on settlement behaviour, development, growth, and survival of American lobster postlarvae, and evidence that mud bottom can serve as secondary nursery habitat

Abstract

Postlarval American lobsters, Homarus americanus, prefer settling onto a cobble substrate and delay settling onto other substrates. Using tanks lined with cobble, mud, or sand, I found that postlarvae settled first onto cobble, second onto mud, and last onto sand. Furthermore, postlarvae moulted sooner on cobble than on mud, and sooner on mud than on sand. The longest delay of settlement, over large, sand-lined tanks, resulted in reduced carapace length and mass at the next moult in comparison to postlarvae which settled earlier onto mud or cobble. The costs of delaying settlement could encourage settlement onto less-preferred substrates when cobble is unavailable. Accordingly, I deployed passive collectors onto mud habitat in Maces Bay, NB, Bay of Fundy. These collectors were colonized by juvenile lobsters ranging in size from young of the year up to adolescents. Consequently, I identify mud habitat as an overlooked nursery habitat for American lobster settlement and early life history.