Seasonal variations in biochemical composition and condition index of cultured mussels ( Mytilus galloprovincialis Lmk) in the Lagoon of Venice (North Adriatic)

Abstract

Seasonal changes in the main biochemical components and in the condition index of cultured mussels ( Mytilus galloprovincialis Lmk) from the Venice Lagoon have been followed during the period October 1979–August 1981. Carbohydrates (2–32%) show winter minima and summer maxima, while proteins (30–52%) have a rather irregular pattern. Lipids (2–13%) and condition index exhibit an annual cycle with two minima (late spring; autumn-winter) and two maxima (early spring; summer). Seasonal variations of biochemical composition and condition index are discussed in connection with the reproductive cycle and some environmental parameters such as temperature and phytoplankton availability. The comparison between the present data and those from other geographic areas confirms the peculiarity of the environment of the Venice Lagoon.