A STUDY ON THE TRASH FISH OBTAINED BY THE EGYPTIAN MEDITERRANEAN TRA WLERS.

A STUDY ON THE TRASH FISH OBTAINED BY THE EGYPTIAN
MEDITERRANEAN TRA WLERS.
By
S. I. RIZKALLA*
*National Institute of Oceanography and Fisheries, Alexandria, Egypt.
Composition.
ABSTRACT
The analysis ofthe commercial catch ofthe Egyptian Mediterranean
trcTwlers obtained by 132 trawling trips during the period from
December 1993 to November 1994 showed that it was formed oftwo
main categories: valuable species (economic species) and non valuable
species (trash fish). The latter was divided into: juveniles ofeconomic,
sorted non economic and unsorted non economic species. The average
catch per trip of trash fish through the period ofinvestigation was 331
kg representing 26.57% of the total commercial catch. Juveniles ofthe
economic species constituted about 90.03% of the total trash catch.
Species composition of the trash fish revealed the presence of 36
economic species belonging to 18 families and 26 non economic
belonging to 24 families. Picarels (Spicara flexuosa and Spicara
smaris) were the most abundant species of trash fish constituting
71.31% of the total catch. This was followed by gurnards: Trigla
lucerna & Trigloporous lastoviza (7.30%); groupers: Serranus cabrilla
& Serranus hepatus (7.27%) and sea breams: Pagellus erythrinus &
Pagellus acarne (2.42%). The present study indicates that the majority
of the economic species in the trash fish were too small in size and were
captured before reaching their first sexual maturity. This could be
attributed to the use oftrawl nets having cod ends with small mesh sizes
that retained most ofspecies with small sizes.