Anomalies in the regional weather over the south‐eastern Bering Sea during spring and summer of 1997 resulted in significant differences in nutrient availability, phytoplankton species composition, and zooplankton abundance over the continental shelf as compared with measurements in the 1980s. Calm winds and the reduction of cloud cover in spring and summer produced a very shallow mixed layer in which nitrate and silicate were depleted after an April diatom bloom. High submarine light levels allowed subsequent phytoplankton growth below the pycnocline and eventual depletion of nitrate from the water column to depths of 70 m or more. Thus, total new production during 1997 may have exceeded that of previous years when nitrate was not depleted below the pycnocline. A bloom of the coccolithophorid, Emiliania huxleyi, was observed in early July in the warm, nutrient‐depleted waters over the middle and inner shelf. Emiliania huxleyi concentrations reached 4.5 × 106 cells L–1 by September, and the bloom persisted through the autumn. There was evidence for increased abundance of some species of copepods in 1997 as compared with data from the middle domain in June 1981. The abundance of adult and juvenile euphausiids in 1997 was statistically similar to values measured in 1980 and 1981. However, near‐surface swarms were rarely observed on the inner shelf in August–September 1997. Lack of euphausiid availability in the upper water column may partially explain the August–September mass mortality of planktivorous short‐tailed shearwaters (Puffinus tenuirostris) observed on the inner shelf.

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The distribution of nutrients (nitrate, phosphate, and silicic acid), chlorophyll and primary productivity were examined in the central and eastern Aleutian Archipelago. The data were collected from moorings (temperature, salinity, nitrate, and currents) and two hydrographic research cruises

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During the late summer of 1997, for the first time ever recorded, most of the continental shelf of the eastern Bering Sea was covered by aquamarine waters (Figure 1), resulting from a massive bloom of coccolithophores (Figure 2). Light reflecting off the calcium carbonate plates of the flagellated coccolithophores gave the water its anomalous color, which was first observed in July. The bloom was also clearly visible from space, as shown by some of the first images from the multispectral sea‐viewing wide‐field‐of‐ view sensor (SeaWiFS) scanner in September. Light penetration into the water column, essential for primary production by diatoms and other phytoplankton, was markedly reduced. This shift potentially altered the trophic dynamics throughout the food web of one of world's most productive ecosystems.

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Background: Satellite-based oceanographic data products are a valuable source of information on potential resource availability for marine species. Satellite oceanography data may be particularly useful in biotelemetry studies on marine species that feed at low trophic levels, such as zooplanktivorous whales, sharks, and rays. The basking shark, Cetorhinus maximus, is a well-documented zooplanktivore in the western North Atlantic, yet little is known of its movements and spatial ecology in this region. A combination of satellite tag technologies were used to describe basking shark movements with respect to concurrent satellite-observed oceanographic conditions in order to test for selection of these environmental variables. Results: Satellite-linked 'smart' position only transmitting tags (SPOTs, N = 10) were used to assess horizontal movements, activity space, and habitat selection, while pop-up satellite archival tags (PSATs, N = 7) were used to describe depth preferences of basking sharks during summer and fall. The duration of SPOT tracks ranged from 5 to 45 days. Basking sharks used relatively small activity spaces in three focal areas off Massachusetts: Vineyard Sound, the Great South Channel, and Cape Cod Bay. These sharks appeared to select areas with shallow bottom depths, high primary production and chlorophyll concentrations, and steep surface gradients, but significant selection for these variables was only detected between mid-August and mid-October when the sharks were primarily located in Cape Cod Bay. Conclusions: Basking sharks in the southern Gulf of Maine during summer and fall focus their activities in discrete areas likely to support high primary and secondary productivity. Habitat selection may also be influenced by mating and social activity at times, but further research is needed to differentiate these behaviors from foraging activity. Satellite-based biotelemetry and oceanography are powerful tools that together can provide valuable new insights into habitat selection patterns of highly mobile marine species.

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