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| Registros recuperados: 25 | |
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| Hansen, J.E.. |
| Collete and Chao (1975) reviewed the systematic and morphology of the Genus Sarda and relatives ((Tribe Sardini), including into their analysis a few S.sarda from the SW Atlantic. Before that, Demir (1964)dealt with the meristic data of the same species from the Black Sea. This paper in concerned with the featuring of the bonito caught in Argentina, from both a morphometric and a meristic point of view. The study made the differences reported by Collette and Chao (op.cit.)among W and E S.sarda populations to be more conspicuous, because our samples had even lower values han those from the NW. |
| Tipo: Journal Contribution |
Palavras-chave: Meristic counts; Morphometry. |
| Ano: 1988 |
URL: http://hdl.handle.net/1834/1966 |
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| Hansen, J.E.; Buratti, C.C.; Garciarena, A.D.. |
| Advise on Biologically Allowable Catch (BAC) for Southern Argentine anchovy (Engraulis anchoita, 41° S-48° S) during 2012. To assess the evolution since 1990 and the current status of Argentine anchovy Southern stock, an Age Structured Population Model (ASPM) was used. Modeling of catches according to a four-month period pulses allowed to predict annual yields so as to get them close to the nominal catches officially recorded. Some independent indexes of stock abundance (eight acoustic estimates of total biomass and five estimates of spawning stock biomass obtained with the Daily Egg Production Method) and the proportion of individuals per age group assessed during the same cruises were used to calibrate the fitting. No stock-recruitment function but a... |
| Tipo: Journal Contribution |
Palavras-chave: Stock assessment; Yield; Statistical models; Age composition; Clupeoid fisheries. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5508 |
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| Hansen, J.E.. |
| The aim of this paper was to accurately estimate population parameters of northern (“bonaerensis”, latitude < 41° S) and southern (“patagonic”, latitude 41° S) Argentine anchovy stocks and to describe some aspects of their behaviour. The research surveys allowed to obtain data on length, total weight, sex, maturity and age of 27,853 specimens of the northern and 12,787 of the southern stocks. Besides, 20,717 age determinations stemmed from commercial landing samplings of the northern stock were established. Sex proportion in the northern population was 0.50 : 0.50; the southern showed a slight predominance of males (0.52 : 0.48). Data derived from cruises and commercial landings showed statistical differences in the growth ratio of the northern stock... |
| Tipo: Journal Contribution |
Palavras-chave: Pelagic fisheries; Stocks; Population characteristics; Growth; Natural mortality; Sexual maturity; Engraulis anchoita; Marine environment. |
| Ano: 2011 |
URL: http://hdl.handle.net/1834/4884 |
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| Hansen, J.E.; Gru, D.L.; Perrotta, R.G.. |
| An extensive area of the continental shelf -between 37°20' and 34°40'S - was reviewed through hidroacoustical methods in order to evaluate the anchovy biomass. Within the area of highest concentration, further data on anchovy abundance were recorded, and fish samples were taken. Large anchovy shoals were located at about 170 nm from Mar del Plata, mainly in zones with sharp changes in oceanographic conditions. The distribution of the species was not uniform, but "contagious", and the log-normal distribution provided the best fit for the echo-integrator recorded data. The biomass was estimated at 1,061,727 tons (Confidence limits in between 921,010 and 1,223,930 tons). Some parameters of the population were estimated, such as: lenght-weight relationship,... |
| Tipo: Journal Contribution |
Palavras-chave: Length-weight relationships; Sex ratio; Age composition; Growth curves; Echo surveys; Mortality; Age composition; Sex ratio; Mortality; Http://aims.fao.org/aos/agrovoc/c_29093; Http://aims.fao.org/aos/agrovoc/c_7014; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1986 |
URL: http://hdl.handle.net/1834/2038 |
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| Hansen, J.E.; Hozbor, N.; Lagos, N.; Martos, P.. |
| To estimate the biomass of six species, the stratified design used at present for demersal coastal fish stocks is compared against other design alternatives. Density data (t mn-2 between 34ºS and 42ºS, from the coast line to 50m depth, corresponding to whitemouth croaker (Micropogonias furnieri), patagonian smoothhound (Mustelus schmitti), stripped) weakfish (Cynoscion guatucupa), angular angel shark (Squatina guggenheim), brazilian flathead (Percophis brasiliensis) and skate (Sympterygia bonapartii) collected in surveys carried out in spring and winter in the Argentine Sea (SW Atlantic), were analyzed. The spatial distribution of the species was strongly contagious and influenced by bottom salinity. Different marine zones that showed special salinity... |
| Tipo: Journal Contribution |
Palavras-chave: Stock assessment fishery surveys coastal fisheries stratification spatial analysis modelling demersal fish Micropogonias furnieri; Mustelus schmitti; Cynoscion guatucupa; Squatina guggenheim; Percophis brasiliensis; Sympterygia bonapartii PSW; Argentina; Buenos Aires ASW; Uruguay swept area marine environment. |
| Ano: 2010 |
URL: http://ocenadoc/1554veasecualser |
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| Wöhler, O.C.; Giussi, A.R.; Hansen, J.E.. |
| Sequential population analysis on Long Tail Hake (Macruronus magellanicus)from the Southwest Atlantic. Years 1985-1995. VPA on the Long Tail Hake (Macruronus magellanicus), based on data covering the years 1985 up to 1995, was performed to assess the current state of the stock. Simulation trials, inducing uncertainty about both the natural mortality rate and recruitment were also accomplished, to evaluate the risk of overfishing which is associated to different fishing alternatives, always under the assumption of a single and closed Long Tail Hake population. CPUE data were not appropriate for tunning, so the traditional VPA has been applied. During the period of study, stock biomass and spawning stock biomass showed an increased trend. Long and short-term... |
| Tipo: Journal Contribution |
Palavras-chave: Stock assessment; Fishery management; Catch/effort; Fishing mortality; Overfishing; Biomass; Sexual maturity; Stock assessment; Fishery management; Biomass; Overfishing; Sexual maturity; Http://aims.fao.org/aos/agrovoc/c_24251; Http://aims.fao.org/aos/agrovoc/c_24026; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_34068; Http://aims.fao.org/aos/agrovoc/c_7016. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/1875 |
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| Hansen, J.E.; Madirolas, A.. |
| Two pelagic surveys to study were carried out during 1993. Those surveys covered the regions inhabited by either the bonaerensis stock in october (34-41°S)and the patagonian stock in November - December (41-45°30'S). Pre-stratified random sampling designs, including two random steps to allocate the transects, were adopted to perform the acoustic sampling by echo integration. A midwater trawl net (9-16 m vertical opening, 10 mm mesh-sized codend)was used to collect fish samples. The biomass of the northern stock was acoustically estimated to be about 1,45 million tons, whereas that of the southern stock was almost 740,000 t. Young anchovies, up to two-year old, allow for most of theose abundance values within each stock. The arrays of individuals at the sea... |
| Tipo: Journal Contribution |
Palavras-chave: Pelagic fisheries; Geographical distribution; Biomass; Mortality; Echo surveys; Stock assessment; Geographical distribution; Biomass; Stock assessment; Pelagic fisheries; Mortality; Http://aims.fao.org/aos/agrovoc/c_5083; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_24251; Http://aims.fao.org/aos/agrovoc/c_5659; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1996 |
URL: http://hdl.handle.net/1834/1955 |
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| Cassia, M.C.; Hansen, J.E.. |
| The Patagonian cod (Salilota australis) inhabits the SW Atlantic from 38°S up to 55°S, as well as the Pacific Ocean from 40°S up to 57°S. The annual catches of this species by both the Argentine fleet and those operating around the Malvinas Islands have significantly increased during the decade 1990-2000, peaking to 16,556 t in 1996. After this, a marked decrease in landings was noticed, and during 2003 the catch was 7,924 t. Seasonal distribution, concentration grounds, and population structure of the Patagonian cod from the Argentine Sea are described, and the mean densities of the species are seasonally related to latitude, temperature and depth, on the basis of data from surveys carried out by the INIDEP research vessels in 1992 and 1993. Highest mean... |
| Tipo: Journal Contribution |
Palavras-chave: Gadoid fisheries; Seasonal distribution; Population density; Population structure; Biomass; Population structure; Biomass; Population density; Http://aims.fao.org/aos/agrovoc/c_6115; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_6112. |
| Ano: 2005 |
URL: http://hdl.handle.net/1834/1561 |
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| Hansen, J.E.; Garciarena, A.D.. |
| As part of the research programs performed yearly at the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP, Mar del Plata, Argentina) some important basic data about the commercial fisheries usually included in internal reports are registered. This formal paper is a review and summary of size and age composition estimates of commercial catches (discards included) of Northern Argentine anchovy (34ºS-41ºS) obtained between 1990-2011. The basic data resulting from the examination of 521 samples from fishing vessels included 62,466 fish length measurements and 26,667 valid age readings from which the corresponding 22 annual age-length keys were built. The annual estimates of the individual total length-total weight relation parameters and of... |
| Tipo: Journal Contribution |
Palavras-chave: Pelagic fisheries; Stock assessment; Commercial fishing; Catch composition; Age composition; Size distribution; Clupeoid fisheries. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5502 |
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| Hansen, J.E.; Madirolas, A.. |
| Information resulting from four spring acoustic surveys carried out between 1993 - 1996 to assess bonaerensis anchovy (Engraulis anchoita) biomass (34°- 41°30´S) is presented. Annual estimates, successively higher, went from 1.5 to 5.3 millon tons and the respective coefficient of variability that followed the same trend ranged between 7.4. and 28.0. . In general terms, the largest abundances were those recorded within the coastal strata off the Río de la Plata followed by those of the most southern stratum. Nevertheless, during the 1996 survey, the latter showed very high biomass values and, consequently, the largest mean. The region corresponding to the main commercial anchovy fishing ground during the season represented, in any case, relatively low... |
| Tipo: Journal Contribution |
Palavras-chave: Echo surveys; Biomass; Sexual maturity; Growth; Mortality; Biomass; Growth; Sexual maturity; Mortality; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_3394; Http://aims.fao.org/aos/agrovoc/c_7016; Http://aims.fao.org/aos/agrovoc/c_4945. |
| Ano: 1999 |
URL: http://hdl.handle.net/1834/2531 |
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| Wöhler, O.C.; Hansen, J.E.; Giussi, A.R.; Cordo, H.D.. |
| Period 1985-2001. A stock assessment of Patagonian hoki of the Southwest Atlantic was carried out by using data from the years 1985-2001. A cohort analysis, fitted with some survey abundance indices was used in an adaptive conceptual framework. Simulation trials were performed to project the evolution of the fishery, to evaluate the risk of over-fish the stock under different exploitation levels, and to estimate Biologically Acceptable Catches (BAC). Both total biomass and spawning stock biomass showed increasing trends resulting from four strong year classes (1993, 1995, 1996 and 1998). Total biomass at the beginning of 2001 was estimated to be 2.5 million tons, and spawning stock biomass at the spawning time (August) was estimated to be around 1.28... |
| Tipo: Journal Contribution |
Palavras-chave: Stock assessment; Fishery management; Biomass; Risks; Demersal fisheries; Stock assessment; Fishery management; Biomass; Demersal fisheries; Http://aims.fao.org/aos/agrovoc/c_24251; Http://aims.fao.org/aos/agrovoc/c_24026; Http://aims.fao.org/aos/agrovoc/c_926; Http://aims.fao.org/aos/agrovoc/c_2173. |
| Ano: 2007 |
URL: http://hdl.handle.net/1834/2525 |
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| Madirolas, A.O.; Hansen, J.E.; Cabreira, A.G.. |
| The annual research planning of the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP, Mar del Plata, Argentina) includes at least two surveys to estimate the total biomass of Argentine anchovy Northern and Southern stocks. The assessment is performed using hydroacoustic techniques and the Daily Egg Production Method. In this paper the results of the acoustic estimates obtained during the 1993-2008 period are summarized. Besides, the studies performed to determine the characteristics of the species behavior such as vertical migrations or avoidance reactions to vessels that would produce uncertainty about estimates absolute value are discussed. |
| Tipo: Journal Contribution |
Palavras-chave: Pelagic fisheries; Stocks; Echo surveys; Echo integrators; Abundance. |
| Ano: 2013 |
URL: http://hdl.handle.net/1834/5493 |
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| Registros recuperados: 25 | |
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