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Deep-Water Eels from Cook Strait, New Zealand

Material and Methods

Material and Methods

The eels which form the basis of this account represent the major part of the apodal material collected from east of Cook Strait by the Department of Zoology, Victoria University of Wellington, and from near Kaikoura by Mr. R. Baxter, a commercial fisherman, during the years 1956-1957. The area represented by the collections covers about 165 square miles, extending from well south-east of Cape Palliser, with depths of 1,500 fathoms, south with 800 fathoms and south of Cape Turakirae with 500 fathoms. Actual depths fished varied from 450 to 1,300 fathoms, but the majority of collections were made in about 600 fathoms. A number of specimens were collected off Kaikoura in about the same depth. Collecting methods were (a) trawling with "open" bathypelagic cone-nets, (b) longlines and (c) baited traps attached to longlines. When the two latter methods were used eels often made up the bulk of the catch.

Skeletal material was prepared and studied by dissection, maceration, alizarin-stained whole mounts, or wherever possible, by X-ray photography. Measurements of specimens were made to the nearest millimetre by dividers; drawings were made directly from the specimen in the case of larger structures and by a standard camera lucida in the case of scales and small skeletal structures. Proportional measurements ore given as follows: Total length: snout tip to extremity of caudal fin; standard length: snout tip to distal end of upper hypural; head: snout tip to posterior margin of opercular membrane; snout: snout tip to anterior margin of eye; eye: horizontal diameter; interorbital: least fleshy space between the dorsal margins of the eyes; postorbital: posterior margin of eye to anterior extremity of pectoral base; cleft of mouth: snout tip to angle of mouth when open; predorsal: snout tip to origin of dorsal fin; preanal: snout tip to origin of anal; depth: maximum depth of body, unless where stated; branchial interspace: distance between ventral or posterior extremities; pectoral: anterior extremity of base to tip of fin when held against body. Vertebrae were counted to include the terminal element bearing the hypurals.

The faunal areas of the ocean are given as in Grey (1956, pp. 78-79). The deep-sea fauna is that below 100 fathoms; the terms abyssal and deep-abyssal have been added to define the faunas below 500 fathoms and 1,000 fathoms respectively. The continental shelf extends from the coast to 100 fathoms; the continental slope extends from 100-2,000 fathoms: the abyssal plain is located below 2,000 fathoms.