Overholtz and Fnedland: Recovery of the Gulf of Maine-Georges Bank complex 



599 



from 0.30 in 1968 to 0.09 in 1982 (Fig. 8A). During 1983- 

 93, herring were captured in an increasing proportion of 

 survey hauls; by the 1990s, the herring proportion in all 

 survey tows was over 0.60 (Fig. 8A). Autumn surveys dur- 

 ing the 1960s and 1970s also showed a declining trend in 

 the proportion of stations containing herring. This decline 

 was even more pronounced than in spring, with the pro- 

 portion of herring at less than 0.05 of the sample sites 

 during 1979-81 (Fig. SB). This trend began to change in 

 1982 and by the 1990s the proportion of tows with herring 

 was well over 0.40 (Fig. 8B). 



Spring distribution maps from selected years ( 1970-951 

 show that significant changes in herring distribution oc- 

 curred during 1968-98. In 1970 herring were encountered 

 at 74 sites in the central Gulf of Maine (GOM), on south- 

 ern Georges Bank (GB), and across the continental shelf 

 from south of Nantucket to Chesapeake Bay (Fig. 9). Dur- 

 ing 1975, fewer sampling locations (39 sites) had herring 

 and the distribution was constricted. The complex was 

 confined to a few areas in the central GOM, on southern 

 GB, south of Cape Cod, and off of Long Island (Fig. 9). In 

 1980. fish were encountered (89 sites) along eastern GB 

 and found across western-southern GB to south of Long 

 Island. During 1985. the spring distribution (48 sites) was 

 more restricted than in 1980. By 1990 Atlantic herring 

 were found at 101 sites throughout the GOM, western 

 and southern GB. and across the shelf from Cape Cod to 

 Chesapeake Bay. In 1995, herring were even more widely 

 dispersed (108 sites) across the continental shelf 



Abundance of herring from these selected spring re- 

 search survey years reflect the general decline in the stock 

 in the late 1970s and recovery to much higher levels in 

 the late 1990s (Fig. 9). In 1970, herring were abundant 

 over the entire continental shelf from Nantucket to Ches- 

 apeake Bay with the highest abundance off Long Island 

 and New Jersey (Fig. 9). During the late 1970s, through 

 the mid 1980s, herring were less abundant and the largest 

 catches (101-500 fish per station) were generally taken 

 south of Cape Cod (Fig. 9). By the 1990s, herring were 

 abundant over a wider area and catches in the 101-500 

 fish-per-tow range were common. 



Maps of autumn survey catch locations depict significant 

 spatial changes in herring distribution during the past 30 

 years (Fig. 10). In 1965 postspawning fish were located (47 

 sites) in the central GOM, on Jeffreys Ledge, Nantucket 

 Shoals, and the shelf-slope break along western to north- 

 ern GB (Fig. 10). In 1970 herring were caught at 25 sites 

 (mostly in the GOM and on eastern GB), in 1975 at only 

 18 sites, and in 1980 at only one location (along the coast 

 of Maine). The number of capture sites increased in 1985 

 (17) when herring were found primarily in the Stellwagen 

 Bank-Jeffreys Ledge region, and at a few sites on Georges 

 Bank (Fig. 10). In 1990, herring were widely dispersed 

 (31 sites) along the coast of Maine, Jeffreys Ledge, and 

 Nantucket shoals, and in 1995 herring were dispersed 

 throughout the entire region (75 sites) (Fig. 10). 



In the early part of the autumn survey time series, her- 

 ring were widely dispersed, but not very abundant. In 

 1965, only a few tows had catches greater than 50 fish 

 (Fig. 10). During 1970-85 very few herring were taken 



_L 



0.0 

 1968 1974 1980 1986 1992 1998 



0-7 rB 



1963 1970 1977 1984 1991 1998 

 Year 



Figure 8 



Proportion of survey tows with positive occurrences of 

 Atlantic herring with a LOWESS curve for the data from 

 (A) spring bottom trawl surveys during 1968-98 and (B) 

 autumn bottom trawl surveys during 1963-98. 



and most tows represented only single fish (Fig. 10). By 

 1990 a general recovery was apparent and catches of 50-t- 

 fish per station were common. Atlantic herring were again 

 abundant along the coast of Maine, on Jeffreys Ledge, and 

 in the Great South Channel area ( Fig. 10 ). In 1995, herring 

 were abundant over the entire Gulf of Maine-CJeorges 

 Bank region. 



Survey abundance indices of herring in the Gulf of 

 Maine, on Nantucket Shoals, and on Georges Bank, in- 

 creased greatly since the mid 1980s, but at different rates 

 (Fig. 11). Increases in the GOM (range 2.8-85.9 million fish, 

 1987-98) and GB (range 2.1-120 million fish, 1991-98) 

 regions appeared to be about equal in magnitude although 

 the recovery in the GOM began earlier than on GB (Fig. 



