ABSTRACT
In the North Atlantic, the seastars Asterias forbesi and A. rubens are ecological analogs, and probably share a common ancestor. The continental shelf environments of the NW Atlantic (A. forbesi) and NE Atlantic (A. rubens) differ principally in marine climate. Therefore, each species probably is physiologically adapted to its unique climatic environment. Interspecific differences in the annual caeca/gonad cycle may represent such physiological adaptations. In a coastal sublittoral population of A. forbesi from New York studied from 1980 to the present, spawning occurred from late June to mid-July at bottom temperatures of 16–18°C. Feeding is minimal from June through August, the period of highest temperatures. Between April and May, a proportion of accumulated oocytes increase to spawning size, possibly reflecting translocation of nutrients from caeca to ovaries.
