Publication Abstract

Year-class detection reveals climatic modulation of settlement strength in the European lobster, Homarus gammarus

M.R.J. Sheehy and R.C.A. Bannister

Understanding the nature of recruitment relationships in the European lobster, Homarus gammarus, has been an intractable problem because of difficulties associated with quantification of its scarce planktonic larvae and early benthic phase. We attempt to address this problem by analyzing the age composition of a population off the northeast coast of England. Age-dependent in situ deposits of neurolipofuscin in the eyestalk are used as an age index. An approach is presented that accounts and (or) corrects for the two most important potential sources of error in age determinations by this technique, namely environmental temperature variation and unexplained individual variation. This yields, for the first time in very long-lived clawed lobsters, reproducible catch age structures with year-class resolution. The method should be generally applicable to crustaceans. Cross-correlation analysis shows that larval settlement strength in the European lobster is associated with local sea temperatures and onshore winds in a manner similar to that reported for other lobsters. These findings have important implications for stock assessment, particularly the use of traditional models dependent on size and steady state, yield forecasting, the effects of global climate change, arguments about spawner protection or restocking, and the spawner–recruit relationship.

Reference:

M.R.J. Sheehy and R.C.A. Bannister, 2002. Year-class detection reveals climatic modulation of settlement strength in the European lobster, Homarus gammarus. Canadian Journal of Fisheries and Aquatic Science, 59(7): 1132-1143.