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| Registros recuperados: 25 | |
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| Pájaro, M.; Hansen, J.E.; Leonarduzzi, E.. |
| Engraulis anchoita northern stock reproductive biomass (SSB) during the 1993-2008 period was estimated applying the Daily Egg Production Method (DEPM) and accuracy of estimates assessed using a bootstrap technique (SW Atlantic Ocean, Argentine Sea). The basic data were collected in different research surveys carried out in late Spring, at the peak of the spawning season. The aim of this work was to build reliable confidence intervals around the estimates of the mean reproductive biomass applying a non-parametric bootstrap method. Resampling methods are becoming increasingly popular as statistical tools as they are robust and do not require the assumption of any particular distribution of the basic data. This is especially relevant when assessing the DEPM... |
| Tipo: Journal Contribution |
Palavras-chave: Spawning; Stocks; Fecundity; Biomass; Statistical analysis. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5494 |
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| Wöhler, O.C.; Giussi, A.R.; García de la Rosa, S.B.; Sánchez, M.F.; Hansen, J.E.; Cordo, H.D.; Alvarez Colombo, G.L.; Incorvaia, I.S.; Reta, R.; Abachián, V.E.. |
| An assessment survey on the austral fish was carried out during the summer 1997 on both the shelf and slope off southern Argentina. The cruise covered 101,508 nm2 between 45° and 54° 30'S and depths between 50 and 400 m. The survey did not include the area controlled by the United Kingdom. Considering the total area as an undivided stratum, a random sampling was used to estimate demersal fish biomass and a delta distribution-based model to evaluate mean densities. Out of the forty five species caught 28 were bony fish and 17 elasmobranch. Four cephalopod mollusc species were also identified. A biomass of 3.2 million tons (CI(95o/o): 1.90 - 6.06 millions) proved that longtail hake was the most abundant resource within the region followed by common hake... |
| Tipo: Journal Contribution |
Palavras-chave: Demersal fisheries; Fishery surveys; Biomass; Population structure; Feeding; Parasitism; Environmental conditions. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/5782 |
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| Hansen, J.E.. |
| This paper deals with the commercial landings of bonaerensis anchovy at the Port of Mar del Plata (Buenos Aires province,Argentina), during the years 1986 to 1990. The mean catch was 15,501t per year. A total of 59 fish samples were taken for total length distributions (N=20164), and 24 sub-samples (N=2370) were analyzed to record individual data (length, weight, sex, sexual stage, age fromotoliths reading). The numer of fish per kg ranged between 28 and 53(mean=34.6). The mean size was 156.63 mm, and the most abundant fish in the landings were those being 3 and 2 years old, as it was also recorded during the period 1980-1985. Ordinary length-weight relationships by season were fitted, and the results were as follows:1) Autumn-Winter: W=8.5* 10-7* L3.392;... |
| Tipo: Journal Contribution |
Palavras-chave: Length-weight relationships; Size distribution; Sexual maturity; Clupeoid fisheries; Biological sampling; Age composition; Commercial land use; Cohort analysis. |
| Ano: 1997 |
URL: http://hdl.handle.net/1834/5794 |
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| Hansen, J.E.; Cousseau, M.B.; Gru, D.L.. |
| A total of 7263 otoliths were collected from anchovy samples taken during two pelagic cruises which were carried out in the Spring of 1978. An statistical analysis of back calculated length distributions of one-year-old fish (L1)was made. The L1 mean values taken by geographical latitude form a cline, with higher values in the northern samples, and decreasing Southwards. Within this latitudinal gradient two main anchovy populations can be identified, one in the region of Buenos Aires Province and the other in Patagonian waters. The L1 of the females is significatively larger than that of the males for the former population, whereas in the Patagonian area differences between sexes are not significant. The parameters of the von Bertalanffy Growth curves, as... |
| Tipo: Journal Contribution |
Palavras-chave: Stock identification; Otolith reading; Growth curves; Mortality; Mortality; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1984 |
URL: http://hdl.handle.net/1834/2043 |
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| Registros recuperados: 25 | |
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