380 



Fishery Bulletin 90(2), 1992 



43-1 



41 

 47 



45 



43 







V 



Summer 







41 



4 



Fall 



:,Ai 



..,.^•3^''^' 



70 



68 



66 



1 T" 



64 



1—^ 



Abundance 



#100-1000 

 • 10-100 

 . 1-10 

 0.1-1 



62 



60 



58°N 



Figure 2 



Distribution and relative abundance (x catch per 20-min 

 square) of river herring from spring (1979-89), summer 

 (1970-89), and fall (1978-84) groundfish surveys conducted 

 off the Atlantic coast of Nova Scotia. Area sampled is in- 

 dicated by shading, and mean catch (n/tow) for each 20-min 

 square is represented by a solid circle, scaled to catch level. 

 Isotherms for 2, 5, and 10°C of bottom temperature are also 

 indicated. 



band along the edge of the Scotian Shelf from Emerald 

 Bank east to Sable Island Bank (Fig. 3). This distribu- 

 tion reflects the location of the Soviet and Cuban silver 



47 



45 



43 



41 



47 



45 



43 



41 - 



°W 







.rriTi' 



Spring 



S €^t 



t--- ^-^ U*, " ' *• *'-*^w 



^' 



V 



Summer 



^^^ 



'X>^' 



70 



T — I r 



68 



66 



T 1 1 r 



62 



64 



60 



58''N 



Figure 3 



Spring and summer set locations of river herring bycatch 

 from foreign and domestic fishing operations on the Sco- 

 tian Shelf recorded by Canadian International Observers, 

 1980-89. 



hake fishery (M. Showell, Bedford Inst. Oceanogr., 

 Dartmouth, N.S. B2Y 4A2, pers. commun., Jan. 1991) 

 and indicates a more widespread occurrence of river 

 herring along the shelf break than was apparent from 

 bottom-trawl surveys. Bycatch from domestic fishing 

 operations during spring occurred on the edge of 

 Western and Emerald Banks and corresponds with 

 catch locations from spring groundfish surveys. 



Summer bycatch locations were similar to spring but 

 extended further south and west along the shelf edge, 

 with clusters of catches on the northern edge of 

 Georges Bank, off southwestern Nova Scotia, and in 

 the mouth of the Bay of Fundy (Fig. 3). River herring 

 distribution along the shelf break, as indicated from 

 spring and summer bycatches in the silver hake fishery, 

 reflects the spatial distribution of that fishery. The 

 number of summer observations from a reduced 

 foreign fishing effort (n 86) was much less than spring 

 (n 460). In both seasons, most bycatches occurred in 



