Data/hora: 01/06/2024 16:29:41

Provedor de dados: | Ocean Docs: e-repository of  publications
País: | Belgium

Título:

Evaluación de la biomasa de adultos desovantes, distribución vertical y variación cuantitativa de la intensidad de los desoves de la anchoíta (Engraulis anchoita) durante la primavera de 1982

Biomass assessment of adult spawners, vertical distribution and quantitative variation of the anchovy (Engraulis anchoita)egg production during spring 1982

Autores: | de Ciechomski, J.D.; Sánchez, R.P.; Lasta, C.A.
Data: | 2007-11-06
Ano: | 1986
Palavras-chave: | Vertical distribution; Fish eggs; Spawning populations.
Resumo: | Ichthyoplankton was sampled in 9 exploratory cruises in the sea off Buenos Aires province (Argentina), Uruguay and Brazil, during the spawning peak of the anchovy in spring-early summer and mid-autumn. The most abundant speices in the ichthyoplankton was Engraulis anchoita, representing 88. of the eggs and 76. of the larvae collected in all the cruises. These percentages vary boath regionally and seasonally; as regards eggs, the lowest percentage (10. ) was found in January. The distribution of anchovy eggs and larvae, covered almost entirely the surveyed area, with the exception of hte region influenced by the River Plate estuary. Minimum salinity tolerance for the species eggs was 23.5o/oo. The eastern limit of the distribution of anchovy eggs, extends in spring-early summer to the 200 m isobath in the northern part of the study area, whereas in the south rarely extends beyond the 50 m isobath. Anchovy larvae showed a wider distribution, penetrating in November and December in the brackish waters of the Samborombón bay, extending over more off-shore waters in January. As the spawning season progressed a southwards movement of intensive reproduction nuclei was observed. The average daily egg production during spring-early summer was estimated at 260 anchovy eggs/m2/day; in autumn, a ten-fold reduction of this production was observed. On the basis of the seasonal egg production for spring-early summer, calculated at 3.5238 E15 eggs and the larvae census carried out in mid-January a 98.2. mortality during the imbryonic and larval stages of the anchovy could be assumed. The spawning biomass of the anchovy during this period was calculated at 2,514,970 t. Preliminary results on the vertical distribution of anchovy eggs and larvae show that their distribution is generally restricted to the upper 50 m water layer, with higher concentrations at 10 to 25 m depths.
Tipo: | Journal Contribution
Idioma: | Espanhol

Identificador:

Revista de Investigación y Desarrollo Pesquero, 5. p. 30-48

0325-6375

http://hdl.handle.net/1834/2040

Editor: | Mar del Plata: Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP)