FISHERY BULLETIN: VOL. 84, NO. 3 





INZ 



NORTH LABRADOR SEA- 



HUDSON STRAIT 



CARTWBIBMT 



" HOPEDALE CHANNEL 



.Q 



NCWTOUNDLAND 



33 35 



Carapace length (mm) 



Figure 5.— Comparisons of northern shrimp fecundity between areas in 1982 and 1978, based on predicted values from equations in 



Table 1. 



March 1978 in Fortune Bay was 1.0°C, one of the 

 coldest areas. According to Squires (1968), the 

 penetration of Atlantic water into the former area 

 accounts for these warmer temperatures which per- 

 sist throughout the year. In Fortune Bay, however, 

 the deep bottom water is of mixed Atlantic and Arc- 

 tic origin resulting in much colder temperatures. 

 Thus, the lower fecundity in the Fortune Bay sam- 

 ple is likely linked with an overall reduction in pro- 

 ductivity in a cold water environment. Reduced 

 productivity has been observed previously in the cold 

 water habitats of le Fjord du Saguenay, Quebec 

 (Couture 1971) and the Barents Sea (Berenboim 

 1982). 



The sample taken east of Baffin Island showed 

 relatively high fecundity in cold water (0.7°-1.8°C) 

 compared with other cold water areas. Also, average 

 size of females was larger than encountered else- 

 where with largest females carrying clutches in ex- 

 cess of 4,300 eggs. This is similar to a situation in 

 the Sea of Japan where female shrimp carried 

 similar numbers of eggs as those (at comparable 

 lengths) off Labrador. Again, greater sizes were 

 attained and egg counts as high as 4,900 were en- 



countered (Ito 1976). Growth and maturation are 

 delayed in colder water (Allen 1959; Rasmussen 

 1969; Butler 1971) and shrimp in these two cold 

 water environments likely live longer than conspe- 

 cifics on the Labrador Shelf. 



Dupouy et al. (1981) concluded that shrimp off 

 Baffin Island spawned intermittently based on the 

 high proportion of nonspawning females observed 

 during a survey in 1979. If all females do not spawn 

 annually, more time is available for growth. (Oviger- 

 ous females do not molt.) This can account for the 

 larger sizes attained in the colder area. Failure to 

 spawn annually reduces reproductive potential but 

 is compensated to some degree by the large sizes 

 females attain (larger females carry more eggs) and 

 the apparently increased longevity. 



Samples taken in 1982 in the Hudson Strait and 

 North Labrador Sea came from waters of 0.6° and 

 0.5°C, respectively, but only data from the former 

 were significantly different (a = 0.05) from samples 

 taken in the warmer Hopedale and Cartwright 

 Channels. Data from Haynes and Wigley (1969) 

 showed higher fecundity in warmer water (~5°C) 

 of the Gulf of Maine where a 28 mm female can pro- 



556 



