and feeding patterns presumed to occur in the western North 

 Atlantic and Mediterranean seas (Mauchline, 1980; Bigelow, 1927). 

 However, whether or not a diet solely of detrital material can 

 meet the metabolic needs of this species requires further study 

 (McClatchie, 1985). If consumption of detritus in the epibenthic 

 region can be quantified, these euphausiids constitute a huge, 

 heretofore unidentified grazing force which may account for 

 considerable repackaging and bioturbation. Assuming that 

 epibenthic M. norveqica feed more or less continuously, those 

 individuals that migrate vertically each night may introduce 

 recycled biogenic and inorganic materials back into the mixed 

 layer when they release fecal pellets. 



The detection of prodigious epibenthic aggregations of 

 euphausiids is also significant in regard to higher trophic level 

 dynamics throughout the region studied. For example, marine 

 carnivores such as fin-whales ( Balaenoptera physalus ) are known 

 to feed almost exclusively on euphausiids, presumably on patches 

 of high (at least 17 g ■ m"^, ca. 60 individuals ■ m"3 ) biomass 

 (Brodie et al . , 1978). Unpublished data from the Marine 

 Monitoring Assessment and Prediction Program (MARMAP) have 

 indicated that euphausiid densities in the study area average 

 less than 1 • m~^ and range up to 50. Sonar (120 kHz) measured 

 densities of 5-140 euphausiids • m~3 (Sameoto 1983). Our 

 observations that epibenthic krill were at least one to two 

 orders of magnitude higher than mean abundances recorded by net 

 tows or sonar measurements, substantiate that zooplankton do 

 occur in concentrations that can supply daily food rations 

 required by these mammals. We and other scientists (P. Auster, 

 R. Cooper, R. Jones, R. Langton, J. Uzmann, pers. comm. ) have 

 seen demersal fishes (Gadus morhua , Pollachius virens , Merluccius 

 bilinearis , M. albidus , Urophycis tenuis , U. chuss ) and squids 

 ( Loligo pealei and Illex illecebrosus ) feeding on epibenthic 

 populations of euphausiids. These preliminary observations of 

 foraging by cod, hake, pollock and squid weaken the hypothesis 

 that these zooplankton may avoid predation by living near the 

 bottom and support fisheries data that indicate Meqanyctiphanes 

 norvegica is an important food resource for commercial groundfish 

 species (Grosslein and Azarovitz, 1984). Consequently, by virtue 

 of enormous densities, daily migrations, and widespread 

 distribution in nearshore waters, populations of M. norvegica 

 probably impact benthic productivity over a broad geographic area 

 in the North Atlantic Ocean in at least three ways: (i) as 

 sources of biogenic particles (fecal pellets, molts and 

 carcasses), (ii) as bioturbators and transporters of resuspended 

 and flocculent sediments and (iii) as prey for demersal 

 predators . 



ACKNOWLEDGEMENTS 



This work was supported in part by grants from NOAA/OUR and 

 NOAA/UCAP programs. We appreciate assistance at sea from ship 

 and submersible crews aboard the R/V Seward Johnson and R/V Edwin 

 Link . We thank A. Alldredge and R. Larson for suggestions on the 



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