Table 12. Pavesi"s( 1889) classification of Italian traps. 



Order 



Number of Tuna per Year 



Number of Iraps 



First 5,000 or more, sometimes 10,000 7 



Second 2,000 or more, sometimes 5,000 3 



Third 1 ,000 or more, sometimes 3,000-4,000 6 



Fourth 500, not exceeding 1,500 1 1 



Fifth Rarely exceeding 500 12 



Table 13. Catches for the Sicilian and Sardinian traps for 1970-1975, as reported 

 by Miyake (1976) and P. Arena (personal communication). 



Table 14. Maximum, minimum, and average weights per Italian compartment 

 which contained important tuna traps for 1971-1 957. 



golfitani which had appeared in good 

 numbers in 1 967- 1 968 had been prac- 

 tically annihilated by 1972, and that 

 the typical mean weight of the catches 

 had consequently increased from 

 about 150 kg in 1967-1968 to about 

 270 kg in 1972. He characterized the 

 1972 fishery as depending on "the 

 remnants of ancient year classes, with 

 no possibility of compensating for 

 their loss with the younger classes 

 which should have constituted the 

 strength of the catches." Sara (per- 

 sonal communication) also informed 

 us that the early landings in 1973 



consisted of enormous fish, includ- 

 ing one "matanza" (removal of fish 

 from the trap) of 1 1 I fish whose av- 

 erage weight was 470 kg! The catches 

 at the end of the season, on the other 

 hand, were mainly offish weighing 

 about 80 kg. Despite this recruitment 

 of smaller fish, however, the annual 

 catch had still declined drastically 

 and the average weight of the fish 

 caught had increased remarkabiv 

 (Table 10). Sara (personal commu- 

 nication) advised us that the 1975 

 catches consisted of large fish up to 

 June 7-8, after which the\ continued 



with vers small tuna weighing 25-30 

 kg. The season ended about June 10 

 rather liuni at the usual date, about 

 June 24-25. The figures for this year 

 (Miyake 1976) indicated the first real 

 improvement in the stock since 1 970. 

 The size of the catch had increased 

 for the second time, and the average 

 weight of the fish had decreased sig- 

 nificantly for the first time, since 

 1973. 



Samples of the Sicilian trap 

 catches in 1958 and 1965-1971 (Fig- 

 ure 57) suggest that giant fish were 

 most important in all but two years, 

 constitulmg from 35 to 100 percent 

 of the individual samples. The me- 

 dium fish, or goltltani, made up the 

 majority of the catch in two years, 

 and contributed from to 65 percent 

 of the respective samples. Small fish 

 were apparently insignificant in the 

 catches, never exceeding 2 percent 

 of a sample. The golfitani were most 

 important in 1958 and 1 967, and were 

 less so from 1968 on. 



The 13 available samples of in- 

 dividual catches of Sicilian traps 

 (Aloncle et al. 1974, Miyake 1976) 

 provide striking evidence of the ten- 

 dency of the bluefin to school by 

 size. Six samples consisted entirely 

 of medium fish, 122-185 cm long, 

 and si.\ consisted entirely of giants, 

 over 195 cm long. Only one con- 

 tained a mixture of the two groups, 

 including fish from 147 to 233 cm 

 long. The spreads between the mini- 

 mum and maximum lengths ranged 

 from 28 to 39 cm, with an average of 

 33 cm, in the samples of medium 

 fish, and from 34 to 52 cm, with an 

 average of 46 cm, in those of large 

 fish. The 1958 sample (Figure 57) 

 consisted of two catches, taken two 

 days apart One consisted entirely of 

 giant fish, and the other entirely of 

 medium fish. The same situation ex- 

 isted tor samples of two different 

 catches taken in a single trap on the 

 same day in June 1965. This ten- 

 dency to school by size indicates that 

 size data must be collected on a more 

 continuous basis than has been pos- 

 sible in the Italian fishery to permit 

 accurate estimates of the composi- 

 tion of the annual landings. 



The use of purse seines for blue- 

 t'ln tuna was introduced into the Ital- 

 ian waters of the Tyrrhenian and 



58 



