Distribution of Shrimp and Fish By-Catch Assemblages in the Canadian Eastern Arctic in Relation to Water Circulation

Abstract

In the Canadian eastern Arctic, the catches of common species of decapods and fish in bottom trawls reveal a continuum of increasing species richness and abundance in an easterly direction through Hudson Strait. Species richness is greatest in Ungava Bay, where Arctic and Labrador Sea components of the fauna coexist. Over the study area, species could be divided in three associations corresponding to the origin of the predominant water masses: Arctic cod, cottids, zoarcids, and liparids predominate in the Arctic waters of western and central Hudson Strait; Greenland halibut, roughhead grenadier, and three-beard rockling are characteristic of the northern Labrador Sea; pandalid shrimp are abundant in areas of deep (> 300 m), intensely mixed waters near the mouth of Hudson Strait. Pink shrimp (Pandalus borealis) predominates in Davis Strait–Labrador Sea, whereas it is replaced by the striped pink shrimp (P. montagui) in eastern Hudson Strait, reflecting environmental optima in subarctic and Arctic dominated waters, respectively. The yearly catches of striped pink shrimp are highly variable, possibly related to mixing intensity in eastern Hudson Strait. In Canadian Arctic waters, species richness, distribution, and abundance are related to temperature, salinity, mixing, and general circulation of water masses.