Over-wintering growth and losses in a small population of the threespine stickleback, Gasterosteus aculeatus (L.), in mid-Wales

Mark-recapture was used to estimate the population abundance of threespine stickleback, Gasterosteus aculeatus, in a backwater of Afon Rheidol in mid-Wales in autumn and early spring, from 1984 to 1998. For the 0+ cohort, there was no evidence of density-dependent losses (mortality and emigration) or growth in the over-wintering period. No systematic size-dependent loss was detected. There was an inverse relationship between autumn abundance and the annual rate of change in abundance of the 0+ cohort.