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| Sánchez, R.P.; de Ciechomski, J.D.. |
| A bongo sampler fifted with nets of two different mesh sizes, 330 and 505 u. was used to collected 137 ichthyoplankton samples in the coastal areas off Buenos Aires Province in October, 1981. The efficiency of the two meshes for catching anchovy eggs and larvae and total ichthyoplankton was examined. The statistical analysis of the samples shows that there are no significant differences between the numbers of anchovy and total eggs collected by the different meshes. As regards anchovy and total larvae the finer mesh showed as significantly higher catching efficiency. The results of this partial estimate do not suggest that a major revision of the total assessment of the complete stock is necessary. |
| Tipo: Journal Contribution |
Palavras-chave: Stock assessment; Fish eggs; Stock assessment; Http://aims.fao.org/aos/agrovoc/c_24251. |
| Ano: 1984 |
URL: http://hdl.handle.net/1834/2044 |
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| de Ciechomski, J.D.; Sánchez, R.P.; Lasta, C.A.. |
| 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... |
| Tipo: Journal Contribution |
Palavras-chave: Vertical distribution; Fish eggs; Spawning populations. |
| Ano: 1986 |
URL: http://hdl.handle.net/1834/2040 |
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| de Ciechomski, J.D.; Cassia, M.C.. |
| Observations on the embrionic and larval development of Cynoscion striatus are presented. The description are made on the basis of material obtained by artificial fertilization. Eggs are pelagic, spherical, 700-840µ in diameter and with single oil globule of 210µ-240µ. The yolk is homogeneous and the chorion has smooth surface. The embryonic development is short and at temperatures of 19°-20°C hatching takes place, 34-36 hours after the fertilization. The larvae at hatching are small, about 2 mm in length and not advanced in their development. The mouth is not functional and the anus is not open. The oil globule is situated in the posterior part of the yolk sac; the position of the anus is close to the posterior end of the yolk sac and the digestice tract... |
| Tipo: Journal Contribution |
Palavras-chave: Embryos; Fish larvae; Fish larvae; Http://aims.fao.org/aos/agrovoc/c_2924. |
| Ano: 1982 |
URL: http://hdl.handle.net/1834/2045 |
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