HOBART, AUSTRALIA — THE Southern Ocean is home to about 350 species of fish, most of them unique to this area.Few fishermen in the northern hemisphere would recognize the average catch here, which may contain such oddities as the Antarctic Cod, the Icefish, and the Toothfish. Dick Williams, a fish biologist at the Australian Antarctic Division, says the deep water in the Southern Ocean has isolated the fish species around Antarctica. Cold temperatures and deep water have forced the fish to adapt. Many have built-in anti-freeze in their bodies. "They have proteins which act against ice cystals," explains Mr. Williams. The Icefish, for example, has no red blood cells. And the Orange Roughy, which is not unique to the Southern Ocean, has developed higher concentrations of oil to help keep it buoyant and to act as an energy reserve. The fish also can be good eating. Australia and New Zealand now export Orange Roughy to the United States. But Commonwealth Scientific and Industrial Research Organization (CSIRO) fishing industry observers now estimate that a third of the Orange Roughy stocks around Tasmania have been depleted. Both the Australian and New Zealand governments have imposed quotas on their fishermen's hauls. The Orange Roughy stocks may take some time to rebuild. The fish, also known as the deep-sea perch, takes 32 years to reach sexual maturity. It is thought some Orange Roughy, which reside 2,400 to 3,600 feet under the sea, live for over 100 years. A few Tasmanian companies have discovered a new way to make money off the Orange Roughy. They are marketing Orange Roughy oil as a substitute for sperm-whale oil and jojoba oils. Among their products are a lubricating oil and a non-toxic biodegradeable degreaser. CCAMLR will send inspectors on some of the boats fishing in the Southern Ocean this summer. This effort will give CCAMLR a better idea of what the fisherman are pulling up and whether there is a need for tighter restrictions. Currently, the fin fish catch is limited to a total of 200,000 tons per year.