Biology of age 0+ sand flounder Rhombosolea plebeia in the Avon-Heathcote estuary

• Main Author: Kilner, Allan R.
• Format: Other/Unknown Material
• Language: English
• Published: University of Canterbury. Zoology 1974
• Subjects: Christchurch; New Zealand; Webb; Auckland Islands
• Online Access: http://hdl.handle.net/10092/9061; https://doi.org/10.26021/7080

The sand flounder Rhombosolea plebeia (Richardson) (Pleuronectidae) inhabits shallow coastal marine and brackish water regions throughout New Zealand, Auckland Islands and possibly Australia. Relatively little research has been carried out on this important commercial species. The principal investigation up to the present time is an unpublished Ph.D. thesis by Mundy (1968), who carried out a population study involving tagging of adult fish off the Canterbury coast. Some data were provided as part of a study on the fish population of the Avon-Heathcote Estuary by Webb (1966, 1972, 1973a, 1973b). A Ph.D. study on osmoregulation of sand flounder from Otago Harbour has been completed by Raj (1973), and a study of flounder spawning in the Hauraki Gulf has also been recently published by Colman (1973). The shallow water inlets and estuaries around the Canterbury coast act as a nursery for young stages of sand flounder. While some population and feeding studies have been carried out on the older age classes, little is known of its early development, natural history and physiology. The Avon-Heathcote Estuary (latitude 43°32'S., longitude 172°43'E.), the study area in the present investigation (Fig. 1), is one of these nursery areas for the young stages. It is probably the principal area for producing fish to restock the offshore grounds which provide the commercial catches on the east coast of the South Island (Mundy, 1968). Sand flounder is an important commercial species, both in terms of public demand and in the volume of landings. The annual landings of' flounder of all species in New Zealand from 1944-1970 was about 907,730 kg, and of this total sand flounder formed about 50 percent (New Zealand Marine Department, Reports on Fisheries, 1944-1970). Hence the study of its biology in a major nursery area and of the effects of man-made environmental changes and pollution is important. The Christchurch Drainage Board proposes to control flooding in the City of Christchurch and have had several flood control schemes ...