A Biological Study of the Anchovy, Engraulis australis in Australian Waters

Abstract

A biological study was made of the common Australian anchovy, Engraulis australis (White), which occurs in coastal waters south of the Tropic of Capricorn. The occurrences in Victorian waters, where the only fishery exists, were those most fully investigated.

There are three subspecies which are easily recognized by their mean vertebra numbers, in combination with the region of occurrence. E. a. australis (White) occurs in Queensland and in all but the southernmost waters of New South Wales. E a antipodum Gunther ranges from the border region of New South Wales through Victorian, Tasmanian, and South Australian waters. E. a. fraseri n, subsp. occurs in Western Australia. Each subspecies is further divided into local populations which intergrade.

The subspecies antipodtim grows to about 2.3, 2.9, 3.5, 4.2, and 4.7 inches of total length (mean sizes) at 1/2, 1 1/2, 2 1/2, 3 1/2:, and 4 1/2: years respectively, The greatest known length is 6.2 inches. Sexual maturity is usually attained at 1 year. Spawning occurs mainly in the inlets, in summer. The fish inhabit principally the inlet waters, but as they become older they tend to move out to sea in winter and return in spring. n'ithin the inlets, the younger fish are usually found furthest from the sea. There is a special brackish-water population in the rivers entering the Gippsland Lakes.

The growth rate of the subspecies australis is similar to that of antipodum, but the life history ppears to differ in many ways, although the full facts are not clear. There is more spawning in the colder months, and it takes place mainly at sea.

The subspecies fraseri occurs both in inlets and at sea, but the data are insufficient to establish the life history. The growth rate is approximately the same as elsewhere.

Anchovies occur in large numbers in certain inlets, where they can be caught easily with haul seines. In Port Phillip Bay there are proficient anchovy fishermen who cannot dispose of much of the fish they are able to catch. The fish would be suitable for canning whole, for fish paste (for which a little is used now) and for live-bait for tuna fishing. They would not be suitable for oil reduction.

The scale-reading (age) studies yielded some results of general academic interest. The fish-length/scale-length relationship is not the same in all regions, and this affects calculations of gvowth rate. There is slight variation in growth rate between localities, and possibly between year classes and sexes; and apparent but not real variation between age-groups, and between different sizes in each age-group.