576 



Fishery Bulletin 100(3) 



60°N - 

 58 N - 

 56 N - 

 54'N - 

 52'N 



• * • 



1984 



170"W 



160°W 



150'W 



60 N - 

 58°N -j 

 56"N - 

 54°N - 

 52 N  





140°W 



>.. 



1990 



1 70 W 



leo'w 



150W 



140°W 



60°N - 

 58 N  

 56'N - 

 54'N - 

 52 N  



..^■'' 



'iff *• 



1996 



1 70"W 



160°W 



150W 



140'W 



Figure 12 



All sampling locations ( • ) where capelin [Mallotus villosus) were caught 

 in 1984. 1990. and 1996. 



In contrast to strong spatial and depth gradients, there 

 was Httle evidence for strong temporal gradients in the 

 GOA gToundfish community between 1984 and 1996, 

 except for the pronounced increase in total CPUE and 

 a potential decrease in species diversity after 1993. The 

 species composition of the groundfish community in the 

 GOA, as reflected in our indices, has remained relatively 

 stable from 1984 through 1996. Furthermore, a visual 

 comparison of the indices mapped by year (not shown) 

 suggests that relative species composition is character- 

 ized by spatial patterns that were stable from 1984 to 

 1996. Similarly, no apparent shifts in individual species 

 distributions were found. The apparent stability of spatial 

 patterns in the GOA may simply reflect stability in species 

 composition over the time period of the study, as well as 

 a period of relatively moderate variations in the physical 

 environment. It also suggests that recent levels of fishing 

 may not have had a strong impact on the relative species 

 composition, or possibly had a stabilizing effect. The ob- 

 served composition of the groundfish community, which is 



currently dominated by relatively long-lived species, may 

 also contribute to its own stability. 



Some of the most pronounced changes over time oc- 

 curred in noncommercial species such as skates and 

 capelin (Fig. 10). Whether these changes are directly or in- 

 directly linked to fishing or are the result of environmen- 

 tal changes is currently unknown. Interestingly, capelin 

 decreased in abundance in some areas and depth ranges 

 but have been caught at an increasing proportion of the 

 sampling stations in more recent surveys. These changes 

 appear to reflect a "spreading out" of the population at 

 relatively fixed numbers, possibly in response to the in- 

 creasing abundance of large predatory fishes. 



Other studies of gi'oundfish communities have docu- 

 mented relatively stable spatial patterns in species com- 

 position over time periods of 10-20 years (Colvocoresses 

 and Musick, 1984; Gabriel, 1992; Gomes et al., 1992; Jay, 

 1996). In contrast. Gomes et al. (1995) observed a sharp 

 decline in the biomass and abundance of a number of com- 

 mercial groundfish species on the Newfoundland-Labra- 



