Laboratory Experiments on Artificial Reefs for American Lobsters

Abstract

Abstract This laboratory study investigated design features for artificial reefs to be used as enhanced juvenile lobster habitat. These features included size of brick shelters, size of rocks in rock piles, and the character of the underlying substrate. Experiments using brick shelters tested the ability of two lobster sizes (50-59 and 82-89 mm CL) to enlarge shelters by digging in sand-gravel bottom. If the gravel size was 1-2 cm both lobster sizes occupied > 90% of shelters by 22 h and the difference between occupancy at 2 and 22 h was not significant. If gravel size was 3-5 cm or 6-8 cm fewer shelters were occupied and the excavation of the sand/gravel took longer. Piles of three sizes of rocks were each placed on hard bottom as well as sand/1-2 cm gravel bottom, and the number of lobsters occupying each rock pile noted after 2-days. Six times more 70-79 mm CL lobsters and 1.7 times more 50-59 mm CL lobsters occupied rock piles on sand/gravel than hard bottom. For all rock sizes and substrates combined...