< 



10 



— ; 1 1 1 1 1 1 1 1 1 



76 77 78 79 80 81 82 83 84 85 



YEAR 



Figure 11. Annual mean catch of anchovies taken by trawl; the vertical bars are approximated QS'ii confidence 

 intervals for each year. 



Gasterosteus spp., sticklebacks 



The threespine stickleback {Gasterosteus aculeatus) and the blackspotted stickleback {Gasterosteus 

 wheatlandi) are small, nearshore fishes. The threespine stickleback is distributed throughout the north 

 polar regions and as far south as Chesapeake Bay in the Western North Atlantic. The blackspotted 

 stickleback is found only in the Western North Atlantic from Newfoundland to I, IS (Perlmutter 1963). 

 During the spring, both species move into salt marshes and tidal rivers to spawn (Worgan and Fitzgerald 

 1981). However the two species are found in different salinity regimes during their reproductive season, 

 and thus do not compete for resources during spawning (Audet ct al. 1985). The threespine stickleback 

 is the larger fish of the two species. 



Threespine and blackspotted sticklebacks are very similar in appearance and are not easily distinguished 

 (Bigelow and Schroeder 1953). Because of this similarity, the blackspotted stickleback was not identified 

 in MNPS collections until October 1981 (NUSCo 1982a). Although Fitzgerald and Whoriskey (1985) 

 found no size overlap between these two species, the length frequency distributions of individuals collected 



36 



