On the reproductive biology of the females of the shrimp Crangon crangon (L.) (Decapoda, Crangonidae).

A three-type scheme of the reproductive strategy of the females of the shrimp Crangon crangon is proposed. ( 1) The sub-Arctic strategy: summer spawning, long-lasting from early June to mid-July. Each female spawns only once within this time period. Despite it being the summertime, the egg size falls into the range of the 'winter' spawning of the females inhabiting the boreal areas of the geographic range. ( 2) The boreal strategy: the spawning takes place all year round. Two groups of females reproduce: large-size winter-spawning (end of November-early March) laying large 'winter' eggs and summer-spawning (late March-early April till July) laying small-size 'summer' eggs. ( 3) The subtropical strategy: winter spawning (from November through the end of March-beginning of April). The egg size of this group presumably refers to the size of the 'summer' eggs produced by the females inhabiting the boreal areas of the geographical range. Such a reproductive strategy of the females of C. crangon refers to the logic of the 'excluded fourth case,' i.e., either laying the winter eggs during the summer (sub-Arctic), either laying the summer eggs during the winter (subtropics), or both (boreal areas). There is no place for the forth case. [ABSTRACT FROM AUTHOR]