AbstractThe study has recorded the presence of two members of the Atherinidae in British waters, the common sand smelt, Atherina presbyter Cuvier and Boyer's sand smelt, A. boyeri Risso. The latter is a notable find and only the fourth record of the species from British waters. A systematic analysis of samples from eight localities suggests that British atherinids support the present accepted taxonomic scheme for the Atlantico-Mediterranean. silversides.
Aspects of the biology of the two species have been recorded. Individual fish in samples of A. presbyter from Langstone Harbour and Fawley and A. boyeri from Oldbury-upon-Severn were measured, weighed, sexed, and aged, by counting the growth zones in the saccular otoliths. These data were used to determine age and length structure of the population, annual mortality, growth in length and weight, length-weight relationship and sex ratio. Certain phenological parameters were also followed: condition, mesenteric lipid reserves, hepatosomatic index, intestine weight, and gonadosomatic index. The ecology of the two species was also investigated and included an analysis of diet and
infection by parasites.
The gonadosomatic index, fecundity counts, and oocyte size-frequency distributions were used to describe the sexual cycle. Adult A. presbyter were spawned in the laboratory which enabled the ovum to be described and established the pattern of embryo development, time to hatching with respect to temperature, and pattern of postlarval development. The life-histories of the two species were considered in the context of current views concerning the evolution of life-history strategies of small fishes.
The study gives a detailed account of the ecology and biology of A. presbyter, a little studied fish species, and also provides information on an isolated and unstudied population of A. boyeri.
|Date of Award||1979|
|Sponsors||Council for National Academic Awards|