Joseph T. Eastman, Ph.D.

     Antarctica and its fauna command increasing attention in a world aware of global climatic change, destruction of natural habitat and loss of biological diversity. The Southern Ocean surrounding Antarctica is an enormous marine habitat, about one-tenth of the world's ocean. Fishes are an integral component of this ecosystem including the subzero coastal waters. The fauna is dominated by the notothenioids, and endemic suborder of bottom dwelling perciform teleosts. I am attempting to decipher the results of a natural experiment, involving these fishes, that has proceeded over the past 40 million years under unusual conditions in Antarctic waters.

     I am studying the morphology of notothenioids in a phylogenetic (historical) context and therefore seek to answer a series of general questions relating to the nature of Antarctic fish diversity. Why did the fish fauna evolve the way it did? Why is the modern fauna unlike the preceding fossil faunas as well as the shelf faunas of other southern continents? Why do modern notothenioids contribute so heavily to Antarctic fish biodiversity at both the organismal and ecological levels? Are notothenioids an example of an adaptive radiation or a fish species flock? Specific aspects of my current work include mechanisms of buoyancy and the morphology of brains, eyes and the digestive system.

Selected References:

• Lannoo, M.J. and J.T. Eastman. 2000. Nervous and sensory system correlates of an epibenthic evolutionary radiation in Antarctic notothenioid fishes, genus Trematomus (Perciformes; Nototheniidae). Journal of Morphology, 244: (in press).

• Eastman, J.T. and R.R. Eakin. 2000. An updated species list for notothenioid fish (Perciformes; Notothenioidei), with comments on Antarctic species. Archive of Fishery and Marine Research, 48: 11-20.

• Eastman, J.T. and A.L. DeVries. 2000. Aspects of body size and gonadal histology in the Antarctic toothfish, Dissostichus mawsoni, from McMurdo Sound, Antarctica. Polar Biology, 23: 189-195.

• Eastman, J.T. and G. Hubold. (1999) The fish fauna of the Ross Sea, Antarctica. Antarctic Science, 11:293-304.

• Eastman, J.T. (1999) Aspects of the biology of the icefish Dacodraco hunteri (Notothenioidei, Channichthyidae) in the Ross Sea, Antarctica. Polar Biology, 21:194-196.

• Eastman, J.T and R.R. Eakin. (1999) Fishes of the genus Artedidraco (Pisces, Artedidraconidae) from the Ross Sea, Antarctica, with the description of a new species and a colour morph. Antarctic Science, 11:13-22.

• Eakin, R.R. and J.T. Eastman. (1998) New species of Pogonophryne (Pisces, Artedidraconidae) from the Ross Sea, Antarctica. Copeia, 1998(4):1005-1009.

• Eastman, J.T. and M.J. Lannoo. (1998) Morphology of the brain and sense organs in the snailfish Paraliparis devriesi: Neural convergence and sensory compensation on the Antarctic shelf. Journal of Morphology, 237:213-236.