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This study combined data on fin whale Balaenoptera physalus, humpback whale Megaptera novaeangliae, minke whale B. acutorostrata, and sei whale B. borealis sightings from large-scale visual aerial and ship-based surveys (248 and 157 sightings, respectively) with synoptic acoustic sampling of krill Meganyctiphanes norvegica and Thysanoessa sp. abundance in September 2005 in West Greenland to examine the relationships between whales and their prey. Krill densities were obtained by converting relationships of volume backscattering strengths at multiple frequencies to a numerical density using an estimate of krill target strength. Krill data were vertically integrated in 25 m depth bins between 0 and 300 m to obtain water column biomass (g m-2) and translated to density surfaces using ordinary kriging. Standard regression models (Generalized Additive Modeling, GAM, and Generalized Linear Modeling, GLM) were developed to identify important explanatory variables relating the presence, absence, and density of large whales to the physical and biological environment and different survey platforms. Large baleen whales were concentrated in 3 focal areas: (1) the northern edge of Lille Hellefiske bank between 65 and 67°N, (2) north of Paamiut at 63°N, and (3) in South Greenland between 60 and 61°N. There was a bimodal pattern of mean krill density between depths, with one peak between 50 and 75 m (mean 0.75 g m-2 , SD 2.74) and another between 225 and 275 m (mean 1.2 to 1.3 g m-2 , SD 23 to19). Water column krill biomass was 3 times higher in South Greenland than at any other site along the coast. Total depth-integrated krill biomass was 1.3 × 10 9 (CV 0.11). Models indicated the most important parameter in predicting large baleen whale presence was integrated krill abundance, although this relationship was only significant for sightings obtained on the ship survey. This suggests that a high degree of spatio-temporal synchrony in observations is necessary for quantifying predator-prey relationships. Krill biomass was most predictive of whale presence at depths >150 m, suggesting a threshold depth below which it is energetically optimal for baleen whales to forage on krill in West Greenland.

A net sampling survey was carried out for krill in a standard station grid around Elephant Island during 27 January to 4 February 2001. In comparison with recent years the station grid was extended south, where a large proportion of small size classes, one-year-old juvenile krill was found. Results show a spatial separation of the juvenile krill and the spawning stock, Krill density was significantly higher than during the past years (229 krill 1000 m−3 or 13.0 g m−2). The proportional recruitment index for the entire survey area for the 1999/2000 year class was R1 = 0.573, which is among the highest values recorded during the past 20 years. The maturation index (based on the proportion of gravid stages) was G = 0.99, indicating an early initiation of the spawning season. The results indicate a turning point after a succession of years with poor recruitment success and low stock biomass. This is thought to be the first step for a successful spawning event and a later potential recruitment success of the 2000/01 year-class. The spatial extent of the station grid is discussed in the light of a representative coverage of the stock and the estimated recruitment index.

A growth model for pandalid shrimps accounting for seasonal variations in growth is presented based on successive additions of sigmoid functions along a basic von Bertalanffy growth (VBG) equation. Results obtained with this new model are compared with results from the VBG equation and from a VBG model modified by the addition of a sine function. Results show that growth of Pandalus borealis (Krsyer) from Gullmarsfjorden on the Swedish west coast is best described by the seasonal models. Of the 2 seasonal models, the new model gave a slightly better fit. Seasonal variations in growth are discussed in relation to the reproductive cycle of P. borealis. Differences in growth pattern between sexes were also found in a 4 yr series of data from the fjord. The main difference was that male growth declined earlier in the year (late summer-autumn) than female growth which declined later (autumn-winter) and for a longer period. Differences in growth rate between sexes are also discussed. Since Gullmarsfjorden contained 4 different periodically isolated P. borealis populations during the study period (1984 to 1987), the relationship between growth rate and mean ambient temperature could be investigated in the temperature interval of 4 to 6 "C. No correlation between these 2 factors was found. Results also indicated that recurring immigrations of adult shrimp during late winter-early spring from the Skagerrak population did not significantly affect growth-rate estimates. Finally, sizes by age of P. borealis in the fjord did not dlffer s~gnificantly from reported sizes by age In other boreal populations.

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