Has climate variability driven the trends and dynamics in recruitment of pelagic fish species in Swedish Lakes Vaenern and Vaettern in recent decades?

摘要

We analyse trends and dynamics in time-series of recruitment in Smelt and Vendace in the Swedish large Lakes Vaenern and Vaettern, with particular emphasis on the importance of climate variability. Climate-related predictor variables in our analyses were air temperature, water temperature, ice coverage and duration of ice winters. The variation between years with successful recruitment and years with low recruitment was considerable in both species and especially for Vendace. Ultra-oligotrophic Lake Vaettern was characterized by strong pulses in Vendace recruitment, occurring mainly in four year intervals. Smelt recruitment was positively related to recruitment pulses of Vendace. In meso-oligotrophic Lake Vaenern, Vendace pursuit was more successful in years with long ice winters that lasted until the middle of March or longer. Smelt recruitment in Lake Vaenern was positively correlated to the air temperature in April. There was no obvious synchrony in recruitment patterns between the two lakes. Recruitment of Smelt in Lake Vaenern's two main basins was, however, positively correlated. The results indicated that climate factors may influence the recruitment of important pelagic species, but that the effects may differ between lakes, even though the systems are adjacent and situated at the same latitude.