G-29 



Both MerlucciuB hubbBJ anrt Microni"aJ atius austral is outside the Antarctic zone apawn 

 during the spring. Hai't (1946) showml that Morlucciue hubbai on the Patagonian Shelf moves 

 inshore during October and November and Ciechonifjki and Weiao (1973) describe spawning in 

 December. They also state that the eggi; cro O.O-O.9 mm diameter and are pelagic (Ciochomski 

 and UeisB I974). The plankton survey fi'om which the above information was derived was con- 

 ducted between latitudes ^?^ and 47 S ol F the Argentine coast and eggs were fovind throughout 

 the region. In view of the fact that sexually mature fish have been caught in the Scotia 

 Sea in January (Mikheyev I967) it seems highly likely that in view of the distance between 

 these two areas spawning occurs south of 47 although there is no direct information available. 



Hart (1946) suggested that MicromeoistiuB aiistralis spawns 'during the spring and Weiss 

 (1974) has confirmed this from examination of a collection of larvae. Weiss (1974) also con- 

 siders that spawning occurs deeper than I5C m although no specific area is mentioned. 



The presence of mature Micromesistius austral is in the Scotia Sea during the Antarctic 

 summer is assumed to indicate that this apocie:; migrates into the area fixsm the Patagonian 

 region. However, although this explanation fits the observed seasonal distribution of the 

 species in the Southwest Atlantic, it is not cotifirmed as it is possible that spawning con- 

 centrations in the dee]) shelf zone have as y»'t gone undetected. 



The literature on larval stages of other Antarctic: fish is limited to a few papers des- 

 cribing small collections (e.g., Hegan ]91C>, Hybclin 1951, LVerson I96O, Bureau I970). There 

 is no detailed stiidy of development rates although suitable material almost certainly exists 

 in plankton samples. 



8.6 Feeding 



Although a detailed analysis of feeding in outside the scope of the present report, 

 some comment should be made in order to gain a better idea of the position of fish in the 

 ecosystem. Available information for thooe species of potential commercial importance is 

 tabulated in Table 8.25, Tlie preponderance of Nf^totheniids, a predominantly demersal group, 

 largely explains the high fremjenoy of benthic organisms in the diet. The presence of 

 planktonic orga'iisms as well indicates that for some species at least there is probably 

 some diurnal vertical feeding migration or else opportunistic feeding on planktonic organisms 

 migrating down. lixamples of the former are probably Notothonia rossi i and Champsocephalus 

 gunnari (see Fischer 1976) arid of the latter, Hn ja gi^orgianus and Notothenia neglecta . 



8.7 Exploitation 

 Total Catch 



In recent years the total reported catch within the FAO Statistical areas for the 

 Southern Oceaji (Areas 4O, 58 ^''"^ ^^) l^^f been zero. The reason for this is the two areas 

 knovfn to he heavily fished (South Georgia and Kerguelen) are prcsentlj' included in statisti- 

 cal reporting areas to tlie north (4I and 51 respectively). In aridition, of the species 

 considered in this review only two have been reported ai' separate species in the FAO Year- 

 book of Fishery Statistics. These are Southern Pouhassou ( Micromesistius nustralis ) and 

 Patagonian Hake ( Merlucriuo hubbsi). There is therefore no precise information available 

 although it has been suggested (Hureau 1973 and Ijawn unpublished Rejiort) that catches in 

 some areas have been quite large. The following analysis is therefore based on interpreta^ 

 tion of the reported catch in relation to the known fisheries of the area. 



The reported catch of Southern Poutassou in recent years is set out in Table 8.26. 



