Page 3 - Froglia1982

164 C. Froglia

found at depths of 200-350 m on muddy or sandv-muddy bottoms frequently with
Funiculina quadrangu/aris (HELDT, 1954; MAURIN, 1968).

Off western Sicily BOMBACE (1972) recognized a "facies of Parapenaeus
/ongirostris" at about the same depths and related it to the presence of water masses
of atlantic origin (temperature 14° C.).

In the Northern Adriatic 'ea single specimem of P. /ongirostris are found at
depths of 60-70 m (CRNKOVIC, 1970); at the same depths concentrations of
economic interest were recently found off the mediterranean coasts of Israel
(GALIL, personal communication).

During the 1974 fishing cruise around Sicily, conducted by the Istituto di Ricer-
che sulla Pesca Marittima (formerly Istituto di Tecnologia della Pesca), particular
attention was devoted to Decapods.

Whereas the whole material collected will be reported in the near future
(FROGLIA & MANNING, in preparation), data obtained on vertical distribution
and size frequency distribution of Parapenaeus /ongirostris are herein briefly

discussed.
Trawling operations were concentrated in three areas: the Golfo di Patti (NE

Sicily), off the Egadi islands (W Sicily) and off Pantelleria island.
Sampling was carried out with a Mediterranean bottom trawl.
Because of technical difficulties in operating the net, total catches obtained in

different hauls can not be compared each other. Anyway, the highest densities of P.
longirostris were found at depths of 200-350 m.

Sex and carapace length of all shrimps caught in each haul were recorded.
Carapace length, from the eye socket to the posterior margin of the carapace,
was measured, to the millimeter below with caliper; subsequently data were grouped
in two millimeter size classes.
No data are available for the escape capacity of this species through meshes of a
trawl; even if small meshed cod-end (22 mm opening) was used, it is probable that
smaller shrimps were able to escape from the net. For this reason -;ize frequency
distributions obtained cannot strictly be considered representative of the actual
population.
Even though abundance of smaller· size classes may be somewhat
underestimated, some interesting conclusions can be reached from comparison of
the length distributions obtained.
In all three areas and at all depths investigated females outnumber males and
reach a bigger size (Tab. 1).
That probably is a comequence of different growing rhythm in the two sexes
and perhaps of higher longevity of females.

Tab. 1 - Sex ratio and maximum size (mm) recorded for males and females in the
investigated areas.

Area Patti Egadi Pantelleria

Sex ratio 9 I 0' 2.0 1.4 1.5
Male max. length 31 32 29
Female max. length 38 40 35