engleski

Effects of environmental changes on early stages and reproduction of anchovy (Engraulis encrasicolus L.) in the Adriatic Sea

Anchovy spawns in the Adriatic from (March) April to October (November). Egg production and the quantity of yolk-sac larvae follow the changes of primary production and zooplankton quantity during the spawning season, with the phase lag of about two months. Investigations of long-term fluctuations of egg production, quantity of larvae and postlarvae showed that increase of egg production was followed by increase of the quantity of postlarvae but also with the increase of their instantaneous mortality rates. These fluctuations were positively correlated with the fluctuations in temperate, salinity, primary production and zooplnakton quantity, with the phase lag of one year. Since 1978 these "regular" fluctuations have been disturbed. The anchovy biomass decreased, while the temperature, salinity, contents of nutrients and primary production have been continuosly increasing in the entire Adriatic. It seems that these changes were the consequence of a low frequency period of climatic change, probably amplified by the antropogenic eutrophication.

anchovy; early-life history stages; environmental chnages; reproduction; Adriatic Sea

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