Overwintering Strategies of the Calanoid Copepod Calanus plumchrus in a Periodically Anoxic British Columbia Fjord.
Abstract
A study was conducted to determine the excretion physiology and feeding behaviour of overwintering Calanus plumchrus V in Saanich Inlet, B.C. In December, no C. plumchrus V were found above 75m. 48% of the population was within 25m of the bottom. Oxygen concentrations below 75m declined steadily during the winter. By January, water below 150m was anoxic. Overwintering C. plumchrus V from Saanich Inlet would not eat under laboratory conditions. Seven species of cultured phytoplankton and Artemia nauplii were offered as food. Mean ammonia excretion rates were 15.41 and 15.33 x 10-3 micro-gm atoms nitrogen per mg dry weight per day. These values are 10-20 times lower than those previously reported for overwintering copepods. It was calculated that C. plumchrus V had sufficient body nitrogen to survive at least 5 months at the observed rates of nitrogen excretion. It is concluded that C. plumchrus V in Saanich Inlet enter into diapause to survive low winter food levels. Feeding does not occur, protein metabolism is low and lipid reserves are not utilized.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1982
- Accession Number
- ADA124992
Entities
People
- Michael Bruce Cowen
Organizations
- Naval Postgraduate School