5.3 Fishing seasons 



5.31 General pattern of seasons 



The average monthly landings of Auxis at 

 Tosashimizu (Kochi Prefecture), at Hachijo (Izu 

 Archipelago), and at Mera (Shizuoka Prefecture) are 

 shown in Figure 51. At Tosashimizu, where a pole-and- 

 line fishery operates, Auxis are caught throughout the 

 year, but peak fishing usually extends from October 

 through May (Yasui 1975). During the remainder of the 

 year (June-September), some of the pole-and-line boats 

 concentrate on other species; therefore, there is a reduc- 

 tion in fishing effort for Auxis. 



In the region of the South China Sea, the fishing 

 season for Auxis varies considerably. For example, in 

 the Philippines, the fishing season varies for different 

 parts of the island group beginning at any time between 

 November and January and extending into May 

 (Philippine Bureau of Fisheries 1973). In Thailand and 

 West Malaysia, however, the landings of /luxjs, Euthyn- 

 nus af finis, and Thunnus tonggol are usually better dur- 

 ing the latter half of the year (Kume 1973). 



Fishing for A. thazard in Indian waters begins about 

 August and extends to about December (Nair et al. 

 1970). Sivasubramaniam (1973), who examined the 



JAN FEB MAR APR MAY JLNE JULY AUG SEPT OCT NOV DEC 



Figure 51. — Landings of AilxU spp. average by month from 

 catches made between Januar>' 1%9 to December 1976 at Tosashi- 

 mizu, between Januar>' 1969 and October 1974 at Hachijo, and 

 between Januar\' 1967 and December 1974 at Mera. Japan iYasui 

 1975). 



seasonal and annual variations in the catches of frigate 

 tuna from waters surrounding Sri Lanka, observed that 

 in the south and southwest coasts, A. thazard are caught 

 throughout the year but in the east and north coasts, 

 they are caught primarily in June-September and lesser 

 amounts in March-April. 



In the Maldives, catches of Auxis, combined with that 

 of kawakawa, peak at least twice a year (Hiebert and 

 Alverson 1971). In 1965, for example, combined catches 

 of Auxis and kawakawa in the Maldives peaked in 

 January at 1.2 million fish, declined sharply in 

 February-May to <0.6 million, then fluctuated ir- 

 regularly until September after which the catch rose to a 

 second minor peak in November before declining again 

 in December. 



At Barbate, Spain, A. rochei appear in the trap 

 catches in May-July with the heaviest catches occurring 

 in the first 2 months. About 53% of the catch is com- 

 posed of A. rochei and the remainder consists of little 

 tunny and bonito (Rodriguez-Roda 1966). At Tarifa, 

 bullet tuna constitute 95'^c of the trap catches and 

 average 67.1 t annually. Here, the trap fishery is active 

 in May-June. The traps at La Linea make the largest 

 catches of small tunas with A. rochei accounting for 97% 

 of the catches. The fishing season extends from August 

 to October but most of the catches are made in the first 

 2 months. 



5.32 Dates of beginning, peak, and end of season 

 See section 5.31. 



5.33 Variation in date or duration of season 



At Tosashimizu, Japan, where a pole-and-line fish- 

 ery for A. rochei ojjerates, severe fluctuations in the 

 monthly landings usually occur in October-December 

 whereas landings are stable in January-March (Yasui 

 1975). Yasui examined the relationship between sea- 

 surface temperature and monthly landings and found 

 that in years of good fishing, there was a complex distri- 

 bution of surface temperature with 28°C water very 

 close to shore (Fig. 52A), whereas in years of poor fish- 

 ing the warm water was displaced farther offshore (Fig. 

 52B). He concluded that the location of the 28°C 

 isotherm in July-September significantly influenced 

 fishing conditions in subsequent months. Temperature, 

 it appeared, affects the concentration of bullet tuna 

 schools, i.e., their availability to the boats and the 

 length of their stay on the fishing grounds. 



Monthly landings at Mera, where the fish are taken 

 by nets, show that peak fishing occurs in July-Septem- 

 ber (Fig. 51). Yasui (1975) noted that in this fishery, the 

 large, mature fish with high reproductive index are 

 usually taken in June and that progressively smaller fish 

 are taken in subsequent months. The proportion of im- 

 mature fish in the catch increased in July-August and 

 by September all fish were immature. Yasui concluded 

 from these findings that the catch of Auxis at Mera is in- 



52 



