Venerus et al .: Early life history of Pseudopercis semifasciata 



203 



Posttransition 

 Pinguipedidae 

 summer surveys 



70°W 



41 °S 



43 : 



41 °S 



70°W 



B 



Posttransition 

 Pinguipedidae 

 fall surveys 



Camarones 

 Bay 



41 S 



70°W 



1-2702 Juvemles/nmr' O 



2703-6757 Juveniles/nmi 2 O 



6758-13.514 Juveniles/nmP Q 



13,515-27.027 Juveniles'nmpr J 



Camarones 

 Bay 



70°W 



41 °S 



Figure 6 



Distribution of "Piloto" or epibenthic sampler stations (left) and Pinguipedidae posttransition juveniles (right) in the 

 Argentine Sea by season. (A) Summer surveys. (B) Fall surveys. Dot diameter, classified into four categories, is pro- 

 portional to posttransition juvenile abundance at each station (expressed as no. of juveniles/nmi 2 ). 



located off Peninsula Valdes (42-43°S, 63°W), another 

 off the coast between Engano Bay and Isla Escondida 

 (43-44°S, 64°W to the coast), and the third off north- 

 eastern Camarones Bay (44-45°S, 65°W to the coast). 

 These areas are linked to a frontal zone, the Northern 

 Patagonia frontal system, which is highly productive 

 during the spring and summer and could offer reten- 

 tion mechanisms for larvae (Bogazzi et al., in press). In 

 December 1978, Argentine sandperches of both sexes 

 were observed running near Isla Escondida (Ehrlich, 

 personal observ.). In addition, Elias and Burgos (1988) 

 reported great concentrations of Argentine sandperches 

 off Peninsula Valdes (42-44°S) between October and De- 

 cember, based on commercial fishery data for the period 



1981-88. These reproductive grounds are consistent with 

 the principal areas of summer concentration described 

 by Otero et al. (1982). Furthermore, Elias and Burgos 

 (1988) attributed the decline in yields and average size 

 observed in January and February to the dispersal of 

 postspawning individuals. However, initial results from 

 an ongoing tag-recapture program in San Jose Gulf indi- 

 cate that this species may have a high site fidelity and a 

 limited dispersal (Venerus et al., 2003). In this case, the 

 declines in yield and average size as the fishing season 

 progresses could be a consequence of the fishing effort 

 itself. Macchi et al. (1995) detected a decrease in the 

 proportion of females in January, which also may imply 

 an emigration from the reproductive sites. 



