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  • 1
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    Estimación de la edad y el crecimiento de la merluza austral Merluccius australis (Hutton, 1872) del Mar Argentino (2012)
    Details
    Publication Date: 2021-05-19
    Description: Southern hake (Merluccius australis) age and growth were estimated using sagittae otoliths obtained in research cruises and observers programs in the Argentine Sea (SW Atlantic). The only annual growth ring observed, formed by two bands, one hyaline and another opaque, corresponded to winter and summer growth, respectively. According to the analysis of otoliths edge, birthday was established on 1st July. Within the age range observed, that comprised 3-18 year old specimens, age groups 7, 8 and 9 were the most frequently identified in both sexes. Growth parameters estimates showed significant differences between them.
    Description: Se presenta un análisis del crecimiento y una estimación de la edad de la merluza austral (Merluccius australis) del Mar Argentino (Atlántico SO) realizados utilizando otolitos sagittae provenientes de campañas de investigación y del muestreo realizado por observadores. El único anillo de crecimiento anual que se observó, formado por dos bandas, una hialina y otra opaca, correspondió al crecimiento de invierno y verano, respectivamente. De acuerdo con el análisis de borde, la fecha de cumpleaños se fijó el 1º de julio. Dentro del rango de edad observado, que abarcó especímenes de entre 3 y 18 años, las edades 7, 8 y 9 fueron las que se identificaron con mayor frecuencia en ambos sexos. La estimación de los parámetros de crecimiento permitió observar diferencias significativas entre ellos.
    Description: Published
    Description: Merluccius australis, merluza austral, determinación de edad, grupos de edades, anillos de crecimiento, otolitos
    Keywords: Merluccius australis ; Atlántico Sudoccidental, Argentina ; marine environment ; Age determination ; Age groups ; Growth rings ; Otoliths
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 2
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    Biology and fishery of long tail hake (Macruronus magellanicus) in the Southwest Atlantic Ocean. (2018)
    Details
    Publication Date: 2021-05-19
    Description: Long tail hake is one of the most important finfish resources in the Southwest Atlantic Ocean (SAO). This demersal-pelagic fish is widely distributed from 35° S to 56° S between 50 and 800 m depth. In the Patagonian region the species is found on the shelf, associated with three different water masses: Coastal, Shelf and Malvinas Waters, while north of 45° S it is related to the shelf break, following the Malvinas waters. A separate small stock, evident because of its different growth patterns, occurs inside San Matías Gulf. There is no strong difference in growth patterns between sexes, however females are larger than males, principally after the first maturity that occurs at 3 years old. Maximum age observed was 16 years old, but fish older than 12 years are scarce in the population. The dietary composition changes during the life cycle, juveniles are mainly microphagous and adults incorporate larger preys of several invertebrates and vertebrates taxa. Principal food items are zooplankton species; the most abundant are hyperiid amphipods and euphausiids. Fish and cephalopods are secondary prey. Few fish species predate on long tail hake: Southern hake (Merluccius australis), spiny dogfish (Squalus acanthias), and Argentine hake (M. hubbsi). Cannibalism is not reported in long tail hake. Spawning areas have not been detected yet but some signals in somatic conditions allow inferring that this process may occur during spring. A systematic series of summer demersal standard swept area trawl surveys has been conducted since 1992 to assess the population, suggesting that maximum long tail hake biomass was more than 2 million tonnes in the mid 1990's. Those results were employed as an index of abundance in the annual stock assessment to establish the Total Allowable Catch, but neither environmental variables nor economic effects have been considered yet. Fishing activities began during the mid 1970's when yields were not significant, but beginning in the 1980's several fleets targeted long tail hake, increasing catches up to 168,000 t. Products are exported to Europe, Asia and South America.
    Description: La merluza de cola es uno de los recursos pesqueros más importantes del Océano Atlántico Sudoccidental. Este pez demersal pelágico se encuentra ampliamente distribuido desde 35° S a 56° S entre 50 y 800 m de profundidad. En la región patagónica (Mar Argentino), la especie se encuentra en la plataforma continental, asociada a tres masas de agua diferentes: Aguas Costeras, de Plataforma y de Malvinas, mientras que al norte de 45° S se relaciona con esta última masa de agua y se halla restringida al borde del talud continental. Un efectivo pesquero independiente, evidente por su patrón de crecimiento diferencial, habita en el interior del Golfo San Matías. No existen diferencias en el crecimiento entre los sexos, sin embargo las hembras son más grandes que los machos, principalmente después de alcanzada la primera madurez que ocurre a los 3 años de edad. La edad máxima observada ha sido de 16 años, pero los peces mayores de 12 años son escasos en la población. La composición de la dieta cambia durante su ciclo de vida. Con dieta principalmente zooplanctófaga, los principales ítems alimento son los anfípodos hipéridos y los eufáusidos. Los peces y los cefalópodos se incorporan como presa secundaria. No se ha detectado canibalismo en la merluza de cola. Solo pocas especies de peces son sus predadoras: la merluza austral (Merluccius australis), el tiburón espinoso (Squalus acanthias) y la merluza (M. hubbsi). No se han detectado áreas de reproducción, pero algunos indicios en las condiciones somáticas permiten inferir que este proceso podría producirse durante la primavera. Desde 1992 se ha realizado una serie cruceros de investigación con el objetivo de estimar el tamaño poblacional durante el verano. Durante la década de los noventa, la biomasa de la merluza de cola superaba los 2 millones de toneladas, alcanzando actualmente la mitad. Tales estimaciones han sido empleadas como índices de ajuste en la evaluación de abundancia indirecta de la población para poder establecer la captura total permisible. Las variables ambientales y los efectos económicos no han sido considerados aún en el modelo de evaluación. Las actividades pesqueras comenzaron a mediados de la década de los setenta cuando los rendimientos no eran relevantes, pero a partir de los ochenta varias flotas dirigieron su esfuerzo a la merluza de cola, incrementando las capturas hasta las 168.000 t. El procesamiento de las capturas es realizado a bordo y los productos finales son directamente exportados a Europa, Asia y América del Sur.
    Description: Contribución INIDEP 2028
    Description: Published
    Keywords: Biología pesquera ; Evaluación de efectivos ; Merlucciidae ; Macruronus magellanicus ; Merluza de cola ; ASFA_2015::F::Fishery biology ; ASFA_2015::S::Stock assessment
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.55-82
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  • 3
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    Resultados de la campaña de evaluación de peces demersales australes efectuada en el verano de 1997. (2014)
    Details
    Publication Date: 2021-05-19
    Description: 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 (590,000 tons), patagonian cod and notothenids (slightly over 200,000 tons each). Pink cuskeel reached almost 190,000 tons. Among other fish species, only Psammobatis spp: rayswere over 100,000 tons. The main longtail hake concentrations (100 t/nm2) were found between 48° and 52° 30´S at water depths between 50 - 100 m. Size distribution of longtail hake ranged 18 - 110 cm TL with a mode at 54 cm. Fitting of length(cm) - weight (g) relationship parameters resulted in W = 0.0099 * TL 2.7215. Length at 50 percent first maturity (TL(50o/o)) was estimated at 59.4 cm. Distribution patterns, maximum densities, size structures, length - weight relationship and length at 50 percent maturity related to the other above mentioned species are also reported. From 2,669 otolith readings, length growthparameters corresponding to longtail hake were estimated as follows: L?= 88.15 cm TL; K = 0.245 year-1 and t0 = -0.425 years (males) and L? = 100.92 cm TL; K = 0.190 year-1 and t0 = -0.610 years (females). Significant differences between sexes were observed. Age group 3 (year class 1993) was the most abundant (2,600 millions of individuals). Natural mortality (M) estimates for the species ranged 0.22 - 0.269 whereas total mortality (Z) between ages 4 and 11 was estimated to be 0.335. Studies on fish feeding showed that longtail hake, southern blue whiting and common hake ate mainly zooplankton species such as amphipod Themisto gaudichaudii and euphausiid Euphausia lucens as well as small fish(notothenids, longtail hake juveniles, anchovies, sprats). Other predators, including pink cuskeel, southern hake, patagonian cod, spiny dogfish and Raja flavirostris fed mainly on macrocrustaceans, cephalopods (squid and octopus) and fish(notothenids and longtail hake). Cannibalism, representing 65 percent of the total longtail hake ingested, would be exerted only on young-of-the-year fish whereas predation would be suffered by 0 to 3 year old fish. Nematod Anisakis sp. was responsible for the high degree of parasitism found in southern blue whiting. Different parasites were identified in gills, mesentery,liver, stomach, pyloric caeca and gut.Sea surface temperature ranged 7.5 - 12.5°C. A thermic front (0.02°C/km) was found between 50° and 51°S. Bottom temperature decreased as waters became deeper. Encounter on the shelf of low salinitycoastal waters ( 33.2 psu) and outer waters from the Malvinas current (33.8 to 34.2 psu) generated saline fronts mostly between 53° and 54°S. A strong thermocline was found between 47° and 51°S. It registered a maximum gradient of 5°C/mat 50 m deep waters in the central shelf region. Haloclines were found south of 51°S at depths between 50-70 m. Sea water density within the northern region was mainly influenced by temperature values whereas salinity was the key factor southwards. Zooplankton densities ranged 18.5 - 2488.8 mg/m3. The largest biomasses were found in coastal waters within the area of Bahía Grande (50°-52°S) where T. gaudichaudii was the most abundant species. Differences between day and night zooplankton distribution produced important echo traces only during dark hours.
    Description: Published
    Description: relevamientos pesqueros
    Description: pesquería demersal
    Description: condiciones ambientales
    Description: biomasa
    Description: alimentación
    Description: estructura poblacional
    Description: parasitismo
    Keywords: Demersal fisheries ; Fishery surveys ; Biomass ; Population structure ; Feeding ; Parasitism ; Environmental conditions
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 4
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    Biology and fishery of the Southern hake (Merluccius australis) in the Southwest Atlantic Ocean. (2018)
    Details
    Publication Date: 2021-05-19
    Description: Southern hake (Merluccius australis) is distributed mainly south of 50° S around South America, occurring in cold temperate waters of subantarctic origin. In the Southwest Atlantic Ocean (SAO) only adults are abundant. This species is icththyophagous and malacophagous, feeding mainly on long tail hake (Macruronus magellanicus) and several cephalopods (Illex argentinus, Onykia ingens, Doryteuthis gahi). Age and growth studies show significant sexual differences; females grow to a larger size than males. In recent years, the highest biomasses, estimated from trawl surveys using the swept area method, are about 10,000 t. Fish 4 to 8 years old usually dominate commercial landings. Only a few factory trawler vessels have southern hake as a target species. They operate over the main fishing grounds located near Tierra del Fuego and at the eastern mouth of the Beagle Channel. Average annual landings are about 5,000 t.
    Description: La merluza austral (Merluccius australis) se distribuye principalmente al sur de los 50° S alrededor de América del Sur, encontrándose en aguas templado-frías de origen subantártico. En el Océano Atlántico Sudoccidental, solo los adultos son abundantes. Esta especie es ictiófaga y malacófaga, y se alimenta principalmente de la merluza de cola (Macruronus magellanicus) y de varias especies de cefalópodos (Illexargentinus, Onykiaingens, Doryteuthisgahi). Los estudios de edad y crecimiento indican la presencia de diferencias significativas entre sexos, siendo las hembras mayores que los machos. En los últimos años, las biomasas más altas estimadas por el método de área barrida, se encontraron alrededor de las 10.000 t. Las capturas se encuentran principalmente integradas por individuos de 4 a 8 años de edad y solo unos pocos buques factoría arrastreros capturan a la merluza austral como especie objetivo. Dichos buques operan en los principales caladeros, próximos a Tierra del Fuego y a la entrada este del Canal Beagle. Los desembarques promedios anuales se encuentran cercanos a las 5.000 t.
    Description: Contribución INIDEP 2027
    Description: Published
    Keywords: Biología pesquera ; Conducta alimenticia ; Crecimiento ; Historia de vida ; Taxonomía ; Distribución geográfica ; Desembarques comerciales ; ASFA_2015::F::Fishery biology ; ASFA_2015::F::Feeding behaviour ; ASFA_2015::G::Growth ; ASFA_2015::L::Life history ; ASFA_2015::T::Taxonomy ; ASFA_2015::G::Geographical distribution
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.37-53
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  • 5
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    Estudio de algunos aspectos del ciclo vital de la merluza de cola Macruronus magellanicus, Lonnberg, 1907. (2007)
    Details
    Publication Date: 2021-05-19
    Description: Long tailed hake Macruronus magellanicus, is a demersal fish,distributed in the SW Atlantic Ocean, in Malvinas Current waters,from 36° and 55°S, mainly between 50m and 200m depth. The species is also distributed in Chilenian waters in the Pacific Ocean, being caught in the Magellan Strait and the Beagle Channel. Age determination was estimated with the sagittae otoliths, in which only one ring is formed during the year. Growth parameters were calculated directly and with back calculated methodology, no differences were observed between the results. Differences in growth sexes were evident from 3 years old. The oldest age observed was 13. Different distributional areas of adults through out the year could suggest a migratory movement in northern waters of the total distributional area, in deeper waters and near the Bahía Grande. On the other hand,the presence of juveniles in different areas of the continental shelf shallower than 100m, in the San Jorge Gulf, and near Tierra del Fuego e Isla de los Estados (Argentina), should indicate spawning and hatchering grounds. Total and natural mortality rates observed between 0.3 and 0.58 being considerably higher values for a long life species.
    Description: Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales.
    Description: Tesis (Doctorado). Copia en PDF: portada, índice, resumen, referencias bibliográficas.
    Description: ciclo de vida, crecimiento, otolitos, determinación de edad, reproducción, dinámica poblacional, mortalidad, estructura poblacional, zonas de pesca, relevamientos, distribución geográfica, retrocálculo, Macruronidae, Macruronus magellanicus, merluza de cola
    Keywords: Growth ; Otoliths ; Age determination ; Population structure ; Geographical distribution ; Life cycle ; Reproduction ; Population dynamics ; Mortality ; Fishing grounds ; Life cycle ; Growth ; Otoliths ; Age determination ; Reproduction ; Population dynamics ; Mortality ; Population structure ; Fishery surveys ; Fishing grounds ; Geographical distribution ; Back calculation
    Repository Name: AquaDocs
    Type: Theses and Dissertations
    Format: 969445 bytes
    Format: application/pdf
    Format: 151
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  • 6
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    Estimación de la edad, el crecimiento y la mortalidad natural de la merluza de cola (Macruronus magellanicus) en el océano Atlántico sudoccidental durante el verano de 2010 (2014)
    Details
    Publication Date: 2021-05-19
    Description: Estimate of age, growth and natural mortality of longtail hake (Macruronus magellanicus) in the Southwest Atlantic Ocean during summer 2010. Longtail hake (Macurornus magellanicus) total length (TL) and weight (W) growth parameters were estimated and age structure and natural instantaneous mortality coefficient (M) analyzed. Data were obtained within the framework of the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP) “Observers on Board of Commercial Vessels” Subprogramme. The information, derived from the area comprised between 46° S-54° S, was collected during the February-April 2010 period. Sagittae otoliths reading of 5,034 individuals (2,429 males and 2,605 females) between 28-99 cm TL was performed. The maximum ages observed in males and females were 10 and 12 years, respectively. The age structure showed predominance of 4 year old individuals belonging to the 2005 cohort. Adults above 7 years were scarce. Length and weight growth parameters estimated fitting the von Bertalanffy model were L∞ = 85.98, K = 0.25, t0 = -1.20 for males and L∞ = 93.12, K = 0.21, t0 = -1.41 for females and W∞ = 1,824.66, K = 0.27, t0 = -1.16 for males and W∞ = 2,035.76, K = 0.26, t0 = -1.13 for females. Significant differences between sexes were found. Although at the same age females were larger than males, no significant differences in the length weight relation were found. M of 0.27 estimated for both sexes combined falls within the range expected for the species.
    Description: En este trabajo se presentan estimaciones de los parámetros de crecimiento en longitud (LT) y peso (W) de la merluza de cola (Macruronus magellanicus) y se analiza la estructura de edades y el coeficiente de mortalidad natural (M). Los datos se obtuvieron en el marco del Subprograma “Observadores a Bordo de Buques Comerciales” del Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP). Se seleccionó la información obtenida en el área comprendida entre los 46° S y 54° S durante el período febrero-abril de 2010. Se realizó la lectura de otolitos sagittae de 5.034 individuos (2.429 machos y 2.605 hembras) de entre 28-99 cm LT. Las edades máximas observadas en machos y hembras fueron 10 y 12 años, respectivamente. La estructura de edades estuvo principalmente constituida por individuos de 4 años, pertenecientes a la cohorte del 2005. Los adultos de más de 7 años fueron escasos. Los parámetros de crecimiento en longitud y peso estimados ajustando el modelo de von Bertalanffy fueron L∞ = 85,98, K = 0,25, t0 = -1,20 para machos y L∞ = 93,12, K = 0,21, t0 = -1,41 para hembras y W∞ = 1.824,66, K = 0,27, t0 = -1,16 para machos y W∞ = 2.035,76, K = 0,26, t0 = -1,13 para hembras. Se encontraron diferencias significativas entre sexos. A pesar de que, para una misma edad las hembras presentaron mayores longitudes y pesos, no se detectaron diferencias significativas en la relación largopeso entre sexos. El valor de M de 0,27 estimado para ambos sexos combinados se encuentra dentro del rango esperado para la especie.
    Description: Published
    Description: Macrouridae
    Description: Macruronus magellanicus
    Description: merluza de cola
    Description: determinación de edad
    Description: crecimiento
    Description: mortalidad natural
    Keywords: Age determination ; Growth ; Natural mortality
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 7
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    Grenadiers (Pisces, Macrouridae) of the southwest Atlantic ocean: biologic and fishery aspects. (2012)
    Details
    Publication Date: 2021-05-19
    Description: Several grenadier species distribute in the SW Atlantic Ocean. Macrourus carinatus and Caelorinchus fasciatus are more frequently identified in commercial catches and during research cruises. Those benthopelagic fishes, related to subantarctic waters, inhabit at depths beyond 200 m and in high seas, between 36º S-59º S. During the surveys carried out on board of Argentinean research vessels, M. carinatus was present in 4% of the trawls performed. The highest densities (〉17 t nm-2), obtained between 360-380 m depth, at 39º S, decreased significantly southwards. C. fasciatus was caught in 6% of the total trawls and the highest densities (15-35 t nm-2) were found at depths beyond 200 m, south of 52º S. Due to the difficulty encountered to identify them, in fishing statistics they are grouped as ‘Grenadiers’. Nevertheless, in many cases, the correct identification by scientific observers on board of commercial vessels provides useful information to support the data gathered. Grenadiers are caught as by-catch in important fisheries that have the main fishing grounds south of 52º S. Historically, different countries participated in the fishery that shows two evolution periods. In the first, exploitation carried out mainly by vessels from the former USSR reached a maximum of 31,000 t in 1984. In the second, the Argentine fleet caught up to 10,000 t in 2000. At present, freezer and factory trawlers obtain 88% of the catches and longliners 10% of the total.
    Description: Varias especies de granadero se distribuyen en el Océano Atlántico SO. Macrourus carinatus y Caelorinchus fasciatus son las que se identifican con mayor frecuencia en las capturas comerciales y en campañas de investigación. Estas especies de peces bentopelágicos se relacionan con aguas subantárticas y habitan entre los 36º S y 59º S, a profundidades superiores a los 200 m y en alta mar. Durante las campañas llevadas a cabo a bordo de buques de investigación pesquera argentinos, M. carinatus estuvo presente en el 4% de los arrastres realizados. Las mayores densidades (〉 17 t mn-2), que se obtuvieron entre los 360-380 m de profundidad, a 39º S, disminuyeron significativamente hacia el sur. C. fasciatus se capturó en el 6% del total de los lances de pesca realizados; las más altas densidades (15-35 t mn-2) se obtuvieron a partir de los 200 m de profundidad, al sur de los 52º S. La dificultad para identificarlos a simple vista hace que en las estadísticas pesqueras las especies se presenten agrupadas como ‘granaderos’. Sin embargo, en muchos casos, los observadores científicos a bordo de buques comerciales los reconocen debidamente y proporcionan valiosa información para respaldar los datos recopilados. Los granaderos constituyen la captura incidental de pesquerías importantes cuyos principales caladeros se sitúan al sur de los 52º S. Históricamente, distintos países participaron de la pesquería que muestra dos períodos de evolución. En el primero, la explotación, realizada esencialmente por buques de la ex Unión Soviética, alcanzó un máximo de 31.000 t en 1984. En el segundo, la flota argentina capturó un máximo de 10.000 t en 2000. En la actualidad, los buques arrastreros congeladores y factoría obtienen el 88% de las capturas y los palangreros el 10% del total.
    Description: Published
    Description: Caelorinchus fasciatus, Macrourus carinatus, granadero, pesca comercial, arrastre de fondo, pesquería demersal, estadísticas de captura
    Keywords: Atlántico Sudoccidental, Argentina ; Marine environment ; Commercial fishing ; Bottom trawling ; Demersal fisheries ; Catch statistics
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 8
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    Análisis de la unidad poblacional de la merluza de cola (Macruronus magellanicus). Estudio de las variaciones morfológicas somáticas y de los otolitos en relación con su distribución geográfica (2014)
    Details
    Publication Date: 2021-05-19
    Description: To determine the existence of different population units of longtail hake (Macruronus magellanicus) of the Argentine Sea, the meristic and morphometric characters of 861 specimens from two different areas were studied measuring 24 body distances with the landmark methods. Besides, the relation among weight, width and thickness of 806 pairs of sagittae otoliths as a function of length and sex of individuals was analyzed. Using the General Linear Model, the Principal Component Analysis and the Multivariate Analysis of Variance the fitted morphometric variables, the meristic characters and their relation to the Area and Sex factors were assessed. The variability observed does not show any conclusive evidence about the existence of more than one stock in the Southwest Atlantic Ocean.
    Description: Para determinar la existencia de distintas unidades poblacionales del recurso merluza de cola (Macruronus magellanicus) del Mar Argentino se estudiaron los caracteres merísticos y morfométricos de 861 ejemplares provenientes de dos áreas midiendo 24 distancias corporales con la metodología de entramado. Se analizó, además, la relación entre peso, ancho y espesor de 806 pares de otolitos sagittae en función de la longitud y el sexo de los individuos. Utilizando el Modelo Lineal General, el Análisis de Componentes Principales y el Análisis Multivariado de Varianza se evaluaron tanto las variables morfométricas ajustadas como los caracteres merísticos y su relación con los factores Área y Sexo. La variabilidad observada no muestra evidencia concluyente sobre la existencia de más de un stock en el Océano Atlántico Sudoccidental.
    Description: Published
    Description: Macrouridae
    Description: Macruronus magellanicus
    Description: merluza de cola
    Description: identificación de efectivos
    Description: conteos merísticos
    Description: morfometría
    Description: otolitos
    Keywords: Stock identification ; Meristic counts ; Morphometry ; Otoliths
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed , Article
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  • 9
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    Descripción del otolito de merluza de cola (Macruronus magellanicus, Pisces: Merlucciidae) y su utilización en la determinación de la edad. (2015)
    Details
    Publication Date: 2021-05-19
    Description: In this paper a detailed otolith description of Macruronus magellanicus is given and a criterion of age determination by direct observation is established. It was verified that only one annual ring appears in the otoliths which includes a fast-growing zone (opaque ring) formed between December and April and a slow growing zone (Hyaline ring) formed during the resto of the year. According to the knowledge on the spawning period and the month when the hyaline ring is deposited, the species birthdate was established to be July 1st.
    Description: Published
    Keywords: Determinación de edad ; Lectura de otolitos ; Merlucciidae ; Macruronus magellanicus ; Merluza de cola ; ASFA15::A::Age determination ; ASFA15::O::Otolith reading
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp. 1-13
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  • 10
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    Estimación del crecimiento, longitud y edad de primera madurez y mortalidad natural de la merluza de cola (Macruronus magellanicus) capturada por la flota en el océano Atlántico sudoccidental. Año 2012 (2016)
    Details
    Publication Date: 2021-05-19
    Description: The aim of this paper was to estimate length and weight growth parameters, length and age at first sexual maturity and the natural instantaneous mortality rate (M) of longtail hake (Macruronus magellanicus) of the Southwest Atlantic Ocean. The data obtained by scientific observers over 2,062 saggitae otholits of 938 males and 1,124 females belonging to individuals caught by the commercial fleet in February and March 2012 were analyzed. The length range observed, considering both sexes combined, was 34-100 cm TL. The maximum ages registered for males and females reached 11 and 12 years old, respectively. Length growth parameters derived from the fit to the von Bertalanffy model were: Loo = 88.94 cm, K = 0.223 year-1and t0 = -0.883 year for males and Loo = 104.01 cm, K = 0.151 year-1 and t0 = -1.621 year for females, with significant differences between sexes. Weight growth parameters for both sexes combined showed: Woo = 2,641.11 g, K = 0.174 year-1 and t0 = -1.587 year. In order to validate the results as an indicator of the population status, they were statistically compared with those obtained in the research cruise carried out during the same year and in the same operation area of the fleet that did not show significant differences. Length and age at first sexual maturity were estimated at 57.59 cm and 3.18 years; no significant differences between sexes were found. Depending on the method used, estimates of M values ranged between 0.23 and 0.37.
    Description: El objetivo del presente trabajo fue estimar los parámetros de crecimiento en longitud y en peso, la longitud y edad de primera madurez sexual y la tasa instantánea de mortalidad natural (M) de la merluza de cola (Macruronus magellanicus) del Océano Atlántico Sudoccidental. Se analizaron los datos obtenidos por observadores científicos sobre 2.062 otolitos saggitae de 938 machos y 1.124 hembras pertenecientes a ejemplares capturados por la flota comercial en febrero y marzo de 2012. El rango de longitud observado, considerando ambos sexos en conjunto, fue de 34-100 cm de LT. Las edades máximas registradas para machos y hembras alcanzaron 11 y 12 años, respectivamente. Los parámetros de crecimiento en longitud, derivados del ajuste al modelo de von Bertalanffy, fueron: Loo = 88,94 cm, K = 0,223 año-1 y t0 = -0,883 año para machos y Loo = 104,01 cm, K = 0,151 año-1 y t0 =-1,621 año para hembras, con diferencias significativas entre sexos. Los parámetros de crecimiento en peso para ambos sexos en conjunto mostraron: Woo = 2.641,11 g, K = 0,174 año-1 y t0 = -1,587 año. A los efectos de validar los resultados como indicador del estado de la población, se compararon estadísticamente con los obtenidos en la campaña de investigación realizada el mismo año y en la misma área de operación de la flota que no arrojaron diferencias significativas. La longitud y edad de primera madurez sexual se estimaron en 57,59 cm y 3,18 años; no se encontraron diferencias significativas entre sexos. Dependiendo del método utilizado, la estimación de los valores de M varió entre 0,23 y 0,37.
    Description: Published
    Keywords: Macrouridae ; Macruronus magellanicus ; Merluza de cola ; Edad ; Crecimiento ; Mortalidad natural ; Madurez sexual ; Estructura poblacional ; ASFA15::A::Age ; ASFA15::G::Growth ; ASFA15::N::Natural mortality ; ASFA15::S::Sexual maturity ; ASFA15::P::Population structure
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: 22pp.
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