72° 



70° 



68* 



66° 



45° 



44« 



43° 



42° 



1 1 



^ CITIES 



® GEOGRAPHIC REFERENCES 



1 CAPE COD BAY 



2 MASSACHUSETTS BAY 



3 IPSWICH eAY 



4 BOONE ISLAND 



5 OGUNQUIT 



6 eOOTHBAY HARBOR 



7 PEMAOUIO POINT 

 B MUSCONGUS BAY 

 o MOUNT DESERT I 



BAKERS L 



10 GRAND MANAN I 



11 PASSAMAOUOODY BAY 



12 ST JOHN 



13 DIGBY PO«TL» 



''' y^p< 



Figure 22. Geographic references in the Gulf of Maine region. 



preponderant in 1962-1963. Giant 

 tuna have dominated the catches in 

 all the subsequent years (1 964- 1 975), 

 with only negligible numbers of small 

 and medium sized bluefin being re- 

 corded between 1966 and 1970 As 

 in Newfoundland, the modal lengths 

 of the giant bluefin taken in this area 

 in the late 1960s reached high val- 

 ues, over 220 cm, and the size of the 

 smallest fish taken increased signifi- 

 cantly. The latter trend changed in 

 1970-1971, indicating some recruit- 

 ment of younger fish. In subsequent 

 years, however, the catches have con- 

 sisted almost entirely of very large 

 fish, and the mean size has been 

 steadily increasing. Catches of blue- 

 fin less than 8 years old have been 

 insignificant. 



The available data for 1973-1975 

 show a continuing increase in the 

 size of the fish taken, especially by 

 the hook and line and harpoon meth- 

 ods The average weights of fish 

 caught by nets (traps and purse seines) 

 are somewhat lower, possibly because 

 of the tendency of smaller fish to 



school together in greater numbers 

 than the larger ones 



There has been a fairly close re- 

 lationship between the occurrences 

 of medium sized bluefin in Cape Cod 

 Bay and off Nova Scotia, but the 

 important runs of small fish which 

 have occurred in the former area have 

 had no counterpart m the laUer 



The runs of small bluefin in Capo 

 Cod Bay have comprised ages 2-4, 

 and we are aware of only one indi- 

 vidual of age 1 having been reported 

 from this area The age composition 

 of these size groups has often over- 

 lapped, with age 4 fish associating 

 with runs of medium fish, and age 5 

 fish with runs of small bluefin 



b. Cape Hatteras - Cape Cod 

 (Coastal Waters) 



The "Middle Atlantic Bight" 

 (Figure 25) is the usual summer habi- 

 tat of the small (age 1-4) bluefin of 

 the western North Atlantic, although 

 they have occasionally ranged into 

 the Gulf of Maine (chiefiy Cape Cod 

 Bay) as noted above Many traps in 

 this area took bluefin tuna occasion- 



ally, but very few of these are now in 

 operation The bluefin tuna has been 

 one of the most abundant and popu- 

 lar big game species supporting the 

 offshore sport fishery of this area, 

 particularly in its northeastern part. 

 Since 1 961 it has also been the object 

 of a seasonal purse seine fishery 

 which also takes skipjack tuna in 

 some years. Bluefin usually arrived 

 in the area in late June or early July 

 and departed in the early fall, but 

 they sometimes departed as late as 

 November. The size composition data 

 available to us for this area (Figure 

 24) are mainly from the sport fishery 

 for years before 1961, and from the 

 purse .seine fishery for later years. 



As indicated by these histograms, 

 the sport catches ha\e consisted al- 

 most entirely of small bluefin, mostly 

 of ages 1-3 Sport fishing for these 

 bluefin has been very successftil in 

 some years off New York Harbor 

 (Wcstman and Neville 1942, Moss 

 1967) and elsewhere between New 

 Jersey and Cape Cod (Farrington 

 1939, 1949). The best season is un- 

 predictable. Sometimes the early sea- 

 son produces the best fishing, whereas 

 in other yeais there is excellent fish- 

 ing in late summer and early fall, 

 particularly in the grounds off New 

 York Harbor. 



The purse seine fishery began to 

 harvest this stock in 1962 In the first 

 three seasons (1962-1964) consider- 

 able quantities of medium sized blue- 

 fin were taken, but in subsequent 

 years, fish of this group have been 

 rare in this area, as well as in the 

 more northerly waters which they 

 formerly frequented (see above). 

 Trends in the catches are shown in 

 Figure 27 Wilson (1965; and 

 Sakagawa (1976) give details of this 

 fishery and its catches 



The size composition data (Fig- 

 ure 26) suggest some variation in the 

 sizes taken by the various gears In 

 the years when most of the data were 

 from rod and reel catches. 1 94 1 - 1 960, 

 age 1 fish were often important. In 

 the years from 1962 on, when the 

 seine fishery was the chief harvester 

 of young bluefin in this area, age 1 

 fish were important only in some 

 years, notably 1 966 In the first three 

 years (1962-1964) of intensive seine 

 fishmg, fish of ages 4 and 5 were 



25 



