Occurrence, habitat use, and behavior of seabirds, marine mammals, and arctic cod at the Pond Inlet [Northwest Territories] ice edge

Occurrence, habitat use, and behavior of seabirds, marine mammals, and arctic cod at the Pond Inlet [Northwest Territories] ice edge

786 E. BiologicalOceanography Physical, chemical and biological characteristics of the frontal region are presented. High chlorophyll concentrations...

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786

E. BiologicalOceanography

Physical, chemical and biological characteristics of the frontal region are presented. High chlorophyll concentrations and phytoplankton numbers were associated with the lateral thermal discontinuity. Qualitative composition of the diatom population on either side of the front was distinctive; population at the front was a mixture of the populations on either side. Dept. of Biol. Sci., Univ. of Dundee, Dundee DDI 4HN, UK. 82:6163 Bradstreet, M.S.W., 1982. Occurrence, habitat use, and behavior of seabirds, martne mammals, and arctic cod at the Pond Inlet [Northwest Territories] ice edge. Arctic, 35(1):28-40. Some seabirds (such as murres), narwhals, and white whales favor the ice edge as a feeding location. Ringed seals and arctic cod 'live in close association with landfast ice.' Some reasons for these habitat preferences are offered. LGL Ltd., 44 Eglinton Ave. West, Toronto, Ontario M4R IAI, Canada. (ahm) 82:6164 Bradstreet, M.S.W. and W.E. Cross, 1982. Trophic relationships at [Canadiani High Arctic ice edges. Arctic, 35(1): 1-12. High Arctic ice edges support a diverse epontic community characterized at the lowest trophic level by microalgae, primarily diatoms. These are consumed by amphipods and calanoid copepods. The small arctic cod (Boreogadus saida), frequently found close to ice edges, consumes the amphipods, copepods and other zooplankton. The cod in turn are eaten by seabirds and marine mammals, along with the larger invertebrates. Trophic pathways are constructed and discussed. LGL Ltd., 44 Eglinton Ave. West, Toronto, Ontario M4R 1A1, Canada. (sir)

E50. General biology, ecology, biogeography, etc.

OLR (1982)29 (12)

from carnivorous feeding in multitrophic level systems. This, in turn, permits the determination of potential fish production, for any given size fish, from experimental data on zooplankton production using simple equations. Little knowledge of trophic interactions is required. Dept. of Fish. and Oceans, Canada Centre for Inland Waters, Burlington, Ont. L7R 4A6, Canada. 82:6166 Endler, J.A. et al., 1980/82. Alternative hypotheses in biogeography. (Symposium, 27-30 December 1980, Seattle.) Am. Zool., 22(2):349-471; 10 papers. Geographical distribution patterns of animals and plants have recently been explained by 3 different competing biogeographic models: dispersal, vicariance, and ecological determinism. Data are all too often analyzed with respect to only one model. Examples of each approach are presented in this symposium in an attempt to stress the need for integration of the obviously multiple explanations for most species distributions. (mjj) 82:6167 Endler, J.A., 1982. Problems in distinguishing historical from ecological factors in bingeography. Am. Zool., 22(2):441-452. The importance of examining all consequences of a given hypothesis, as well as considering alternatives, is illustrated via the Pleistocene forest refuge and vicariance biogeography models. Alternative hypotheses to the forest refuge model--current ecology and current peripheral isolation---yield predictions which better fit the data; only 1 of 3 predictions by the refuge hypothesis is upheld. The vicariance biogeography model's major prediction, that concordant vicariance sequences should result in concordant cladograms, is rejected; concordant cladograms result 'from common patterns of shared selection regimes and thus do not reflect vicariant patterns.' Univ. of Utah, Salt Lake City, Utah 84112, USA. (msg)

82:6165 Borgmann, Uwe, 1982. Particle-size conversion efficiency and total animal production in pelagic ecosystems. Can. J. Fish. aquat. Sci., 39(5):668674.

82:6168 Furness, R.W. and J. Cooper, 1982. Interactions between breeding seabird and pelagic fish populations in the Southern Bengnela region. Mar. Ecol.-Prog. Set., 8(3)'243-250.

A method is described for defining conversion efficiency in pelagic ecosystems on the basis of particle size, rather than trophic level. This permits calculation of a size-corrected biomass function which can be used to describe total animal production by taking into account biomass losses resulting

With a bioenergetics model, jackass penguins, Cape gannets, and Cape cormorants were estimated to consume 16,500 t of fish/yr, of which 11,800 t were anchovy Engraulis capensis. This represented a total consumption of 1.3 x l0 s Kj. Annual consumption of fish by the seabirds was estimated to represent