Autecology of crangon crangon (L.) with an emphasis on latitudinal trends

Abstract

This review aims to update and extend the synopsis by Tiews (1970) on the biology and fisheries of Crangon crangon (L.). Its wide distributional range along the European coast from the White Sea to Morocco within the Atlantic and throughout the Mediterranean and Black Seas reflects the capability of C. crangon to cope with a wide range of temperature and salinity conditions and is further explained by its migratory capacity. Present knowledge suggests that the limiting factor at the northern cold water edge of its distribution is formed by egg and larval development and at the southern warm water edge by maintenance costs. No information is available about the genetic population structure, but patterns in isoenzymes and in morphometric characters indicate the existence of various subpopulations. Over its distributional range, especially along the north Atlantic coast, clear trends in life-history parameters are observed, most likely reflecting temperature conditions. Due to its generally high abundance, the common shrimp forms a key component in the functioning of coastal shallow ecosystems; however, it is unclear whether the population dynamics of the species is subject to top-down or bottom-up control. On the one hand, C. crangon is an opportunistic feeder with a wide prey spectrum though it remains to be solved whether growth conditions are optimal and only determined by prevailing water temperatures, or whether food limitation is a regulating mechanism. On the other hand, top-down control by predation cannot be excluded since C. crangon is also an important food item for a variety of predators, especially fish species. There are strong indications that predation by C. crangon might regulate some of their prey species. Topics for further research include (1) the analysis of the genetic population structure by means of molecular tools; (2) the study of growth and reproduction in relation to latitude; (3) the application of dynamic energy budgets for the analysis in terms of energy of the various trade-offs, including growth versus reproduction; and (4) the analysis of the mechanisms determining recruitment, especially whether top-down or bottom-up control is occurring.