196 



Fishery Bulletin 103(1) 



Fulco, 1996; Gonzalez, 1998). Pseudopercis semifas- 

 ciata is a multiple spawner with low batch fecundity 

 and an extended reproductive season (Macchi et al., 

 1995; Gonzalez, 1998). There is little information on the 

 early life history of the species because only specimens 

 >20-25 cm are found on reefs and the habitat of juve- 

 niles has not been described. In general, information 

 about the early stages of pinguipedid fishes from the 

 southwest Atlantic Ocean is scarce. De Cabo 3 reported 

 pinguipedid larvae from the Argentine shelf but did not 

 identify the specimens to species level. 



In the present study, we describe development of P. 

 semifasciata from larvae to the posttransition juvenile 

 stage {sensu Vigliola and Harmelin-Vivien, 2001) and 

 analyze data on distribution and abundance on the 

 northern Patagonian shelf. This information is needed 

 to locate main reproductive and nursery grounds for 

 the species. 



3 De Cabo, L. 1988. Descripcidn de tres larvas de peces teleos- 

 teos del Mar Argentino: Mugiloididae, Ophidiidae (Genypterus 

 blacodes) y Tripterygidae (Tripterygion eunninghami). Un- 

 publ. manuscript, 58 p. Facultad de Ciencias Exactas y Natu- 

 rales, Universidad de Buenos Aires-INIDEP. lAvailable from 

 INIDEP: P.O. Box 175 (B7602HSA) Buenos Aires, Argentina.] 



Materials and methods 



Fish larvae and posttransition juveniles were collected 

 during 19 research cruises conducted by INIDEP (Insti- 

 tuto Nacional de Investigacion y Desarrollo Pesquero) 

 between 1978 and 2001. A total of 592 ichthyoplankton 

 samples and 277 juvenile trawl samples were analyzed 

 (Table 1). 



Larvae 



Ichthyoplankton was sampled by using Bongo, Nack- 

 thai, and PairoVET nets. The Bongo net was fitted with 

 300-/<m mesh and a flowmeter. The Nackthai sampler, a 

 German modification of the Gulf V high-speed sampler 

 (Nellen and Hempel, 1969), was fitted with a 400-fim 

 mesh net and a flowmeter. Both samplers were towed 

 obliquely from bottom to surface. The PairoVET sampler, 

 a Bongo-type version of the CalVET, was fitted with 

 two 200- ;<m mesh nets to sample fish eggs (Smith et 

 al., 1985) and was towed vertically. Samples were fixed 

 in a solution of 5% formalin to seawater. During most 

 cruises, depths at which P. semifasciata were located 

 were determined by a SCANMAR sensor mounted on 

 the sampler. 



