The aim of this study was to provide information on the biology of a subtropical population ofthe hermit crab Petrochirus diogenes focusing size structure, sex ratio, reproductive period and morphometric relationships. Monthly samples were done between January and December 1995 at Armação of Itapocoroy, Penha, southern Brazil, using two over-trawls in depths from 6.0 to 10.0 m. A total of 126 individuais were collected. Overall sex ratio did not differ from 1:1. When the sex ratio was analyzed for each size class, it was skewed for females in the smallest size classes while males outnumbered females in the largest ones. The mean size (cephalothoracic length) of P. diogenes was 30.61 ± 12.52 mm and the size structure of this population was skewed to the right. Males were on average larger and heavier than both ovigerous and non-ovigerous females, which, in turn, showed similar sizes and weights. The ovigerous females represented 61% ofall females and occurred from January to April and in September and December. The relationship of cephalothoracic length and both cephalothoracic width and crab weight were isometric. Both crab size and weight showed a negative allometry with shell weight, indicating that larger/heavier crabs use proportionally lighter shells than small-sized ones.

Portunus spinimanus Latreille, 1819 is one abundant Portunidae speeies whieh are eaught by sea-bob-shrimps artisanal fishery in Armaçãodo Itapoeoroy,Penha, Santa Catarina, Brazil. Aiming to analyze its population strueture, a total of 995 males and 1925 fernaleswere eollected by means of overtrawl frorn January to Decernber 1995, between the depthsof 610 10meters,in lhe periodsof morning,afternoonand evening. The width variation of lhe carapaee ranged írom 3.0 to 14.0 em in the males and 3.0 to 11.0emin females. The species presents growth isometric and the males reach width and weight assintoticand bigger that lhe females.The estirnatedfirst maturation width was between 6.8 and 7.6 em, reached with lhe approxirnated age of 15 months. The artisanal fishery in Armação do lrapocoroy is acting with a higher intensity over the juveniles stock.

Alimentação natural de Callinectes ornatus Ordway, 1863 (Decapoda, Portunidae) na Armação do Itapocoroy, Penha, SC - Brasil. No período de janeiro a dezembro de 1995, foram coletados 332 indivíduos de Callinectes ornatus, procedentes da Armação do Itapocoroy (Penha, SC). Foi estudada a alimentação natural da espécie e as variações sazonais da dieta. Os resultados mostram um espectro trófico diversificado, com estratégia alimentar generalista, sendo Algas, Macrófitas, Foraminiferida, Mollusca, Polychaeta, Crustacea, Echinodermata, Osteichthyes e matéria orgânica não identificada, os grupos que compõem sua dieta.

From January to December 1995, 332 individuals of the Callinectes ornatus species were collected from the Itapocoroy inlet in Penha, Sta. Catarina, Brazil to study its natural diet and the seasonal variations of diet. Results showed a diversified trophic spectrum with a generalized dietary strategy comprising the algae, macrophyta, foraminiferida, mollusca, polychaeta, crustacea, echinodermata, Osteichthyes and NIOM (Nonidentified Organic Matter) groups.

Xiphopenaeus kroyeri is the most exploited shrimp specie along Center-South coast of Santa Catarina State, Brazil, by artisanal fishery. In the period from March/1996 to February/1997, 3965 shrimps were collected (1843 males and 2122 females) sampled by over-trawl, with the depth oscillating between 5 and 15 meters. Xiphopenaeus kroyeri shows seasonal fluctuations in its abundance with higher rates in autumn. The population's average total-length varied between 7.5cm and 9.1cm, and the presence of juveniles was common along the year. The males and females get to the first gonadal maturation with 7.4 cm and 9.0 cm length, respectively; these lengths were reached within 6 and 8 months of age.

In the period of January and December, 1995, there were collected by means of overtrawl, 12977 samples of macroinvertebrates and demersal fishes, in the Armação do Itapocoroy, Penha (SC), between the depths of 6 to 10 meters, in the periods of morning, afternoon, and evening. There were registered the incidence of 57 families, 80 kinds and 92 species distributed between the macroinvertebrates and demersal fishes. The families of greater incidence were: Portunidae (30.7%), Strombidae (11.4%), Sciaenidae (11.1%) and Bothidae (10.3%) which all together, contributed with 63.5% of the total samples. The grouping analysis presented greater diversity in the Winter (2.77) and smaller one in the Springtime (1,34); the amplitude of variation H' reflects the great number of species of both occasional and seasonal in the Armação do Itapocoroy.