Development, distribution and relative abundance of the larvae and early juveniles of the pelagic goby Sufflogobius bibarbatus (von Bonde) off South West Africa, 1972-1974
O'Toole, M.J. (1978). Development, distribution and relative abundance of the larvae and early juveniles of the pelagic goby Sufflogobius bibarbatus (von Bonde) off South West Africa, 1972-1974. Investigational Report = Onderzoekverslag, 116. Dept. Of Industries, RSA: Cape Town. 28 pp.
Part of: Investigational Report of South Africa = Onderzoekverslag. Republic of South Africa. Department of Industries. Sea Fisheries Branch: Cape Town. ISSN 0379-1084, more
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| Abstract |
The pelagic goby Sullfogobius bibarbatus is known from the west and south coasts of Southern Africa. During two ichthyoplankton surveys off South West Africa pelagic goby larvae (2,25 -20,0 mm) and early juveniles were found to be abundant and widely distributed in the upper 50-m layer, constituting 61 per cent of all larval forms col1ected. Monthly cruises were conducted between Cape Frio (18°20'S) and Hol1ams Bird Island (24°40'S) from August 1972 to March 1973 and from August 1973 to March/April 1974. The larvae and early juvenile stages up to 30,0 mm standard length are described and il1ustrated for the first time. Spawning occurred along the entire coast frorn July to February. However, the results of both surveys showed that most intensive spawning occurred frorn spring to early summer in the coastal waters south of Walvis Bay. Spawning declined during summer, but the spawning grounds extended further to the north and seawards. Larvae captured in the south during late winter and during spring were associated with relatively cold, low-salinity water (11.0- 16,0°C, 34,85- 35.20°/oo) characteristic of coastal upwelling. Larvae collected in the north were found in areas of mixing between warm, oceanic water and cold, coastal water and occurred over a higher temperature and salini- tY range ( 16,0- 22,5°C, 35.20- 35.80°/oo). The high relative abundance of pelagic goby larvae is not thought to be due to sampling selectivity, successive sampling of larval cohorts, diurnal migration, or vertical displacement by poorly oxygenated bottom water. The wide temporal and spatial distribution of the larvae of al1 size groups suggests that the species is in fact numerical1y an important component of the neritic ecosystem. |
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