Data/hora: 25/06/2024 01:11:17

Biblioteca(s): 	Embrapa Pantanal.	
Data corrente: 	24/03/1999	
Data da última atualização: 	24/03/1999	
Autoria: 	MACKAY, I.; MANN, K. H.	
Título: 	Fecundity of two cyprinid fishes in the River Thames, Reading, England.	
Ano de publicação: 	1969	
Fonte/Imprenta: 	Journal Fisheries Research Board of Canada, v.26, n.11, p.2795-2805, 1969.	
Idioma: 	Inglês	
Conteúdo: 	Egg production by two cyprinids in the River Thames at Reading, England, was studied quantititively from January to June 1966. Roach (Rutilus rutillus) had a short spawning period, shedding all their eggs in one batch, whereas bleak (Alburnus alburnus) had a protracted spawning period and produced two or there batches of eggs. The relationship between egg numbers (Y) and age (X) for roach was given by log Y = 0.0840X + 3.2085; the estimated fecuindity of a 6-year-old fish was 5157 with 95% confidente limits at 4725 and 5631. For bleak the relationship was log Y = 0.0564X + 3.5221, and the estimated fecundity of a 5-year-old fish was 6356 with 95% confidence limits at 5987 and 6776. Combining previously obtained data on population density with new data on sex ratio and percentage breeding in each age class, the population fecundity for roach was about 600 eggs/m2 and for bleak about 3000 eggs/m2. The roach population had lower fecundity than roach populations in other studies and there was some evidence that a proportion of females ceased egg production during the period of the study. the possibility that low fecundity was a response to food shortage is discussed. 	
Thesagro: 	Fecundação; Peixe.	
Thesaurus Nal: 	fecundity; fish.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Pantanal (CPAP)	
Exemplares: 	CPAP - (37654-1) - ADD - SP - -- - SP4283 -  - 4283 - DIS