THE EFFECTS OF REGIONAL TEMPERATURE CYCLES ON THE DEVELOPMENT AND DISEASE SUSCEPTIBILITY OF THE AMERICAN LOBSTER Homarus americanus

Meghan E. Capps* and Heather J. Hamlin
 
 School of Marine Sciences
 University of Maine
 Orono, ME 04468
 meghan.e.capps@gmail.com

The American lobster, Homarus americanus, is part of a multi-billion dollar fishery and is essential to Maine's economy. Shell disease has led to lobster population crashes in southern New England, and with warming waters in the Gulf of Maine and increasing incidences of lobster shell disease moving north up the coast, it is important to investigate possible correlations between temperature and disease susceptibility. It is hypothesized that warming temperatures are increasing disease susceptibility and causing declines in lobster populations.

Lobster larvae are currently being reared at 3 different temperature regimes representative of northern Maine, southern Maine, and southern New England (Figure 1). Gravid females were obtained during May/June of 2015 and larvae were stocked in communal tanks within 12 hours post-hatch. Communal tanks were approximately 95 liters and heavily aerated to reduce cannibalism. Larvae were fed recently hatched artemia twice a day and were moved to individual compartments upon reaching stage IV. Mortality, growth and development stage are monitored for individual lobsters to assess variations among temperature regimes. The objective is to rear larvae for 12 months with major sampling occurring at 6 and 12 months.

Larvae have been preserved at various growth stages for tests of immune function, histology, and gene expression. Immune function will be assessed through analysis of hemolymph extracted from stage IV larvae. The tests of immune function will be discussed, including both technique and results.