DISTRIBUTION AND GENERAL NOTES ON THE SPECIES 349 



appears. 1 The annual catch of snoek at the Cape has varied from some four million to over nine 

 million lb. weight, and between about ^(^23,000 and ^90,000 in value, over a long period between the 

 two wars. The price has shown the usual tendency to inverse relationship with supply, but has 

 maintained a slight superiority over the average for all fish in each individual year for which data are 

 available. 



Some of the main features of the biology of T. atiin in South African seas are succinctly dealt with 

 by Gilchrist (1914, 1916). They are especially abundant in the colder waters off the south-west coast 

 of Africa in late summer and autumn (the peak usually in May). At these times they feed heavily, 

 especially on 'sardines' (Clupea sagax) when available, and become notably fat. They are in full roe 

 towards the end of winter and are found with ripe eggs, and in poor condition, in September (early 

 spring). The seasonal variation in condition is evidently most marked, for Gilchrist has told us how 

 the fishermen used to sign-on for the 'poor snoek' season on 17 September and how they had learnt 

 to look for the first appearance of the ' fat snoek ' about the middle of December. From then until 

 winter (June) is the best period for the fishery. The relative scarcity of Thyrsites in winter and early 

 spring (the spawning period) is attested by returns from all the countries where it is regularly fished. 

 This is doubtless partly due to a slackening of feeding intensity, well known among most fishes when 

 spawning, that will obviously tend to reduce catches of line-caught species ; but some definite migration 

 for spawning purposes may also be involved. 



In Australia T. otiin (locally 'barracouta') is nearly as important as it is in South Africa. The in- 

 formation concerning it has recently been summarized (anonymously) in Fisheries Newsletter (1944, 

 vol. Ill, part 5, p. 2) and there have been previous interesting references to it in that most stimulating 

 publication. Thyrsites ranks third in importance among the individual species of Australian food-fishes, 

 the annual catch averaging some five million lb. weight over the period 1930-44. Large fluctuations 

 in supply are experienced with consequent variations in price. Normally the fish fetch from 8^. to 

 155. per box, but in 1941 the supply fell until the price reached an ' all-time high' of 35. lod. per fish 

 [Fisheries Newsletter, 1941, vol. i, part i, p. 10). Although there had been a steady decline since 1938 

 there was not thought to be any immediate fear of over-exploitation. Previous periodic scarcity of the 

 species had been known, and there is some hint that it may recur with a seven or nine year cycle. It 

 was also observed that the fish are much more difficult to catch, by the prevailing trolling or jig-stick 

 methods, when their natural food is abundant. This was so in 1941, when it was observed that the 

 boats frequently worked through large schools of barracouta, milling among the clupeoids with which 

 they distend themselves, without catching any. This is thought to have been a subsidiary cause of the 

 scarcity. If the tentative suggestion of a seven or nine year cycle of abundance in the Australian 

 stocks of Thyrsites is substantiated, the 'couta' boats should be obtaining peak catches in 1945-6 

 and 1947-8. 



Thyrsites is limited to the most southerly of Australian seas, about 90% of the catch being taken in 

 Tasmania, and most of the remainder in Victoria. In New South Wales it is rare, and farther north 

 it is apparently unknown. I have not been able to find any account of the occurrence of Thyrsites in 

 south-western Australia, but it is reasonably certain that it is found there, for Australian writers add 

 the isolated islands of St Paul in the southern Indian Ocean to the list of localities from which it has 

 been recorded.^ 



In Victoria trolling with a crude development of the native lure, from auxiliary sailing boats of 



1 In the same two years the total trawler landings were from nearly three times to nearly four times as great as 

 those of the other vessels by weight, and from more than three times to nearly seven times as great in value. 



2 I have not yet traced the origin of this record, hut have no doubts as to its validity, for I believe that the 

 distribution of Thyrsites atun is continuous round the world in southern subtropical seas. Local stocks may, however, become 

 distinguishable when more intensively studied, as they will need to be in the future. 



