Ecología reproductiva y hábitos alimentarios del pez angel, Squatinaguggenheim (Chondrichthyes: Squatinidae), en el Distrito Biogeográfico Bonaerense, entre 34° y 42°S
The reproductive ecology and feeding habits of Squatina guggenheim inthe SW Atlantic ecosystem between 34° and 42°S were studied. For the reproductive study, 423 individuals were obtained in 12 research cruises between 2000 and 2004. Reproductive parameters were analyzed in two oceanographic systems, the Rio de La Plata estuary (ERLP), Argentine-Uruguayan waters, and the El Rincon (ER), Argentina, Buenos Aires Prov. The feeding habits were analyzed using 329 stomach contents of individuals taken in ERLP (264)and ER (65 ER). For this study the individuals were reproductively (adults and juveniles)and seasonality (fall-winter and spring-summer)grouped. In ERLP the maximum total length was 920 mm for females and 865mm for males; in ER the maximum TL for females was 940 mm and for males 890 mm. In ER females matured at larger size than ERLP females and have larger total weight for a give total length. Three reproductive stages were observed in adult females: 1)adult, not pregnant with low GSI and small ovarian follicles, 2)adult not pregnant with high GSI and large ovarian follicles, and 3)pregnant females. The simultaneous occurrence of females in stages 1 and 2 indicates that maturation of the oocytes takes 2 years and implies that the female reproductive cycle is triennial. Alar spines were a dimorphic character due to their absence in neither females nor juvenile males. S. guggenheim could be a depth migratory species, seasonal differences in density were observed between spring and winter. The diet of S. guggenheim was composed of 33 preys, including Teleost, Chondricthyans, Crustacea and Squids. The most consumed prey was Cynoscion guatucupa (. IRI = 7.28. ) following by Prionotus nudigula (1.7. ), Engraulis anchoita (1.6. ) and Raneya brasiliensis (1.52. ). The number and TL of preys were increased with the predators TL.