Migrations and Habitat of the Tuna ( Thunnus thynnus L, ), Studied 

 by the Method of the Hooks j with Observations on Growth, on the 

 Operation of the Fisheries, etOo 



The direct evidences of the arrival of tuna from distant regions, 

 borne by the fish itself in its own body in the form of hooks or tackle 

 torn from the lines of fishermen, have been notably increased as a con- 

 sequence of numerous investigations which I have made, to such a degree 

 as to permit reliable deductions on some fundamental pointSo 



There are in all (excepting some minor reports)? 15 hooks and 

 leads from the Mediterranean , which testify to the migrations of the tuna 

 between the various basins of the Mediterranean; 25 hooks from the Atlantic 

 (Tarifa, Northern Spain, the Azores), which demonstrate the passage of 

 tuna from the Atlantic to the Mediterranean; and one Atlantic hook, which 

 shows the movement of tuna from the Gulf of Gascony to Norway^ 



In the last two years, indeed, in addition to those which I have 

 alrSady made known (Rend. R. Ace. Lincei, 1926; Bullo Stat, Acquico et 

 P§che de Castiglione, 1927), I have been able to recover in tuna of the 

 Mediterranean and elsewhere, in spite of the fact that the catch of the 

 tuna fisheries has been extraordinarily small, the following tackles 



Tackle 



Ori 



m 



Place of Recovery 



1927 



1928 



4 leadsi/ 

 3 hooks 2/ 



1 hook?/ 

 1 hook . 

 1 hookZ/ 

 1 hookl/ 

 1 hook 



Cyrenaica (El Mongar, Bengazi) 

 Sicily (Favignana) and 

 Tripolitania (Sliten) 

 Sardinia (Isola Plana) 

 Norway (Oslofjord) 

 ww-w. -. v^^^^v. Sardinia (Peloso) 

 Gascony (probably)Sardinia (Porto Paglia) 

 Algeria (Arzeu) Sardinia (Porto Scuso) 



Constantinople 

 Gulf of Gascony 



Azores 



Gulf of Gascony 



South Ireland 



1/ Three lead jigs of the " zoka" type and one lead of the " skandil" 

 type given me by Dr. A, Benedettio 



~J Spanish hooks for tuna and "bonito" ( Th. alalonga )o That from Favignana 

 was given me by Comm. Caruso j the two from Sliten were found during 

 my stay at that fishery. 



3/ 



i/ 



5/ 



This and the other Sardinian hooks were given to me by the proprietors 

 of the respective tuna traps; Marquis of Villamarina (l. Plana), 

 Dr. de Plaisant (Peloso), Cav, Carpaneto (P„ Paglia), Awo Casaretto 

 (p. Scuso)o 



French double hook for "germon" (Th, alalonga) o 



Spanish hook for tuna and tonito," The origin is given as probable 

 because at one place in Sicily (Porticello) they have now commenced 

 making use, although on a very small scale, bf hooks of this typep 

 brought from Spain, in the fishery for albacoreo This fishery lasts, 

 however, only a few days out of the year, in the spring, and only a 

 few boats participate in it, which removes the certainty but not the 

 probability of the North Spanish origin of the hook in question. 



