PHYSIOLOGY OF THE WOOD BORING MOLLUSC MARTESIA CUNEIFORMIS SAY

¹ Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543

Larvae of Martesia cuneiformis Say settled in greatest abundance (151.5 individuals/square meter surface area of wood substrate) during the months of August, September, and October in a North Carolina estuary. Minimum estimates of post settlement shell growth rates are 0.19 mm/day during the summer months and 0.03 mm/day during the winter months. Gravid adults maintained in the laboratory spawn during physical disturbance of dissection from wood and, in isolated individuals, after thermal stimulation. The first shelled veliger larva has a mean shell size of 69.0 µm long and 60.0 µm high. At 22°C and 30-32 salinity the pediveliger stage, with a mean shell size of 260 µm long and 269 µm high, is reached in 35 days. Larval respiration rate is described by the relationship R = 2.22W^2.42 where R is oxygen consumption (nl O₂/larva/h) and W is dry weight (µg). On starvation larvae predominantly utilize protein and lipid as respiratory substrates. Adult respiration and ammonia excretion rates are described by the relationships R = 17.95W^0.703 and E = 0.133W^0.492 respectively with the units R (µl O₂/individual/h), E (µg at NH₃-N/individual/h), and W (g live weight).