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Secondary production of a population of Perna perna (bivalvia: mytilidae) under conditions of suspended cultivation

Abstract:

The secondary production of different tissues from a population of Perna perna under suspended culture system in Turpialito Bay, Golfo de Cariaco, Venezuela, was examined in the period July 2002 - July 2003. The ventral axis length of the shell and the dry weight of muscle, gonads and somatic tissue were determined monthly so as to examine the relationship of secondary production and elimination of each tissue with environmental factors such as chlorophyll a, total and organic seston, dissolved O2, salinity and temperature. An initial cohort of 1040 mussels with an average weight of 2.01g showed a total production of 4493.08g/rope/year, of which 1344.89g corresponded to gonads, 1057.17g to muscle and 2091.01g to somatic tissues. The largest increments in gonad production were observed in Nov-Dec'02 and Apr-May'03, with negative spawning production from Dec'02 to Feb'03 Maximum increments in muscle production were observed in Nov-Dec'02 and Feb-Apr'03, while those in somatic tissue occurred between Nov-Dec'02 and May-Jul'03. Total elimination was 530.33g/rope/year Principal components analysis indicated that the environmental factors showing a higher relationship with the variance in gonad production were chlorophyll a increase and temperature decrease, while increases of muscle and somatic tissues were better associated with the increase of organic material, seston and chlorophyll a, the factors that modulated the production in this species.