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16( 168 C. Froglia

The length distributions recorded off Pantelleria presented a single peak with a
central value between those found for the second age class in the two other areas.

This is in agreement with the already mentioned different bathymetric distribu-
tion of individuals of different size. It should be noted that in the Pantelleria area,
only depths greater than 400 m were sampled, whereas in the two other areas
shrimps, belonging to the first age class, were obtained only above 400 m.

HELDT (1938), for Tunisian waters, reports the presence of mature specimens
in winter months (november-april). From rearing larvae in aquaria, she assumed
that larval life extended over a period of two months.

At the end of this period the postlarvae obtained had a carapace length of
about 4 mm.

If her results are extended, as reasonable, to Sicilian waters, then the first age
class recognized in our samples, obtained in June, has to be composed of individuals
six months old, originating from winter spawns. The second class will include in-
dividuals with an age of one year and half.
cnriO

CONCLUSIONS

The life cycle of Parapenaeus !ongirostris in the central 0HGLWaUUDQHDQseems to
be completed in two years; a few individuals perhaps can survive three years. Sexual
maturity probably is reached at the end of the first year.

In summer months individuals of the first age class with a carapace length of
about 13 mm, are especially abundant at depths of 150-350 m where, in the in-
vestigated area, the most important trawling grounds for this species are located.

At depths greater than 450 m only individuals belonging to the second age class
are found, but their density is considerably reduced and they become rare at depths
greater than 600 m.

LITERATURE CITED

BoMBACE G., 1972- Considerazioni sulla distribuzione delle popolazioni di livello batiale con particolare
riferimento a quelle bentonectoniche. Quad. Lab. Tecnol. Pesca, 1 (4): 65-82.

CASSIE R.M., 1954- Some use of probability paper in the analysis of size frequency distributions.
Aust. J. Mar. Freshw. Res., 5: 513-522.

CRNKOVIC D., 1970 - Prilog bioloskoj i ekonomskoj problematici Kocarenja u Kanalskom podrucju sje-
veroistocnog jadrana. Thalassia jugoslavica, 6: 5-90.

HELDT J.H., 1938- La reproduction chez les crustaces Decapodes de la famille des Peneides. Ann. Inst.
Oceanogr., 18: 31-206.

aHELDT J.H., 1954- Les fonds Parapenaeus longirostris (Lucas) des mers tunisiennes. Bull. Station

Oceanographique Salammbo, 47: 11-22.
MASSUTI M., 1959- La gamba (Parapenaeus longirostris Lucas). Primeras observaciones en Ios caladeros

del Golfo de Cadiz y Africa Occidental. Inv. Pesq., 15: 51-81.
MASSUTI M., 1960- Estudio del crecimiento relativo de la gamba blanca (Parapenaeus longirostris Lucas)

de Mallorca. Bol. Inst. Espa. Oceano., 102: 23pp.

MAURIN C., 1968- Ecologie ichthyologique des fonds chalutables atlantiques (de la baie Ibero-Marocaine

a la Mauritanie) et de la Mediterranee occidentale. Rev. Trav. Inst. Peches Marit., 32 (1): 147 pp.