Egg hatching rate of the cyclopoid copepod Oithona similis in arctic and temperate waters

An equation is presented to facilitate estimation of the production of the cosmopolitan cyclopoid copepod Oithona similis. The egg hatching rate was studied from Arctic, subarctic and temperate waters covering a temperature interval from -1 to 20.5degreesC. Within this temperature range the hatching rate (HR) increased from 0.03 to 0.42 d(-1). Results from all experiments were fitted to a function HR (% d(-1)) = 4.2176 + 1.7545T (r(2) = 0.98; p < 0.0001), where T = temperature. When combined with site-specific information on temperature, egg:female ratios and the carbon content of females and eggs, secondary production of this ubiquitous species can be readily estimated.