age bluefin were taken off 

 Castellon, Spain, in the fall of 1976, 

 mainly by sardine seiners, but also 

 by sport fishing boats. Rodrlgucz- 

 Roda (1969d) believed that the de- 

 cline in the Spanish Atlantic trap fish- 

 eries for larger bluefin might have 

 been caused by excessive fishing of 

 immature fish. 



Bluefin tuna catches in the west- 

 ern Mediterranean were evidently un- 

 important prior to the development 

 of the French seine fishery' in 1960 

 Combining the data of Miyake et al. 

 (1976) and the Fisheries Agency of 

 Japan (1974, 1975, 1976), it appears 

 that the total western Mediterranean 

 catches varied between 1 ,000 and 

 2,500 tons (approximately) in the 

 years 1965-1973, but rose to about 

 4,200 tons in 1974 The latter figure 

 was due mainly to exceptionally large 

 catches by the French purse seine 

 and Japanese longline fisheries. The 

 fishing of age bluefin in this area, 

 which apparently is very poorly re- 

 corded, appears to be a cause for 

 concern. 



b. Central Mediterranean 



The central Mediterranean (Fig- 

 ure 56) has traditionally been the 

 area of the major bluefin tuna catches 

 in that Sea. The tuna trap has been 

 the dominant gear in the area until 

 recently The oldest trap fisheries 

 were around Sicily and Sardinia, and 

 off the southwestern coast of Italy 

 itself Additional traps were subse- 

 quently installed off Tunisia and 

 western Libya. All of these traps were 

 originally of the Sicilian type (Fodcra 

 1964). Changing conditions have ne- 

 cessitated their modernization 

 through the use of better materials 

 and the adoption of the Spanish de- 

 sign. This process began in Tunisia 

 in 1950 (Anonymous 1952) and in 

 Sicily in 1956 (de Cristofaro 1970). 

 In addition to the ancient trap fisher- 

 ies (Pavesi 1889,Parona 1919,Belloc 

 1961, Sara 1964), bluefin tuna are 

 taken in the central Mediterranean 

 by purse seine (Scaccini and 

 Biancalana 1959, Paini 1975), hook 

 and line (Scordia 1931, 1932; 

 Genovese 1965, Cesareo 1967) har- 

 poon (Scordia 1932, Sara 1968) and 

 longline (Sara and Arena 1967, 

 Shingu et al. 1975). In the early 



kj 10 



<o 



■♦♦♦**♦ 



J? 



♦ ♦*r-^ 



*—*■* ♦♦■»♦♦ » < 



150 200 



LENGTH (cm) 



250 



Figure 54. lengths of bluefin tuna captuicd in I-rance in 1968 and 1%9 ("+" on 

 graph means less than 5%) 



1970s, the traps were failing (San'i 

 1 973) and the purse seiners were be- 

 coming dominant (Paini 1975, 

 Miyake 1976) Catches of the Japa- 

 nese longline fishery' increased from 

 1972 through 1974, but conservation 

 measures which were introduced in 

 1975 curtailed the catch in that year 

 (Kume 1977). Italian longliners 

 whose primary catch is broadbill 

 swordfish al.so take some bluefin tuna 

 (Sarii and Arena 1967). 



Most of the major traps, located 

 off the coasts of southwestern Italy, 

 Sardinia, Sicily, Tunisia and Libya, 

 fished the arrival (prespawning) run 

 of maturing bluefin in May and June, 

 A few, along the eastern and south- 

 ern coasts of Sicily, fished the return 

 (postspawning) run of spent fish in 

 July and August Most of the smaller 

 traps fished "erratic" or feeding blue- 

 fin at various localities otTlhe Italian 

 mainland and Yugoslavia The Medi- 

 terranean trap fisheries have been de- 

 scribed and discussed by Ceiti ( 1777), 

 Pavesi (1889), Parona'(1919), Sella 

 (1929a, 1929b, 1932a, 1932b),Belloc 

 (1961), Sara (1964), de Cristofaro 

 ( 1 970) and others Parona (191 9) (this 

 work was actually completed m 191 4) 



showed locations for some 100 traps 

 in Italian waters These included 

 many which were inactive or unim- 

 portant, or did not fish specifically 

 for bluefin tuna (Sara 1 968). By 1950, 

 only 30 real tuna traps were active, 

 only 14 m 1965 (de Cristofaro 1970) 

 and just seven in 1973 (Miyake 1976; 

 R. Sara, personal commumcation). 



Catches of the Sicilian and 

 Sardinian traps for 1938-1939 and 

 1946-1973, based on statistics from 

 the Instituto Centrale di Statistica 

 (1949, 1951, 1954, 1957, 1960, 1963, 

 1966, 1969, 1972, 1974) are shown 

 in Tal)lc 10. Although data from 

 sources which are probably more ac- 

 curate are available for certain years, 

 this extensive series of records seems 

 most suitable for illusU'ating the long- 

 term trends in the catches. A few 

 traps in the Culf of Sant' Eufemia, 

 Calabria, (Figure 56) also caught 

 prespawning tuna. Three of them for- 

 merly took very large numbers of 

 small fish Pavesi's ( 1 889) data show 

 that the average annual catch per trap 

 for two of these was 4,674 fish with 

 an average weight of 44 4 kg, or 208 

 tons, in 1879-1883. Parona (1919) 

 listed seven annual catches of over 



53 



