Browsing by Author "Ivanovic, M.L."

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Alimentación del calamar Illex argentinus en la región patagónica durante el verano de los años 2006, 2007 y 2008
    (Mar del Plata : Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2010) Ivanovic, M.L.
    The information gathered during four research cruises carried out in January and February of 2006, 2007 and 2008 allowed to analyze the summer feeding pattern of Illex argentinus squid in the shelf and slope of the Patagonian region (43º S-51º S), SW Atlantic Ocean. Intake, that took place during daytime, had its peak as of midday. Of the preys eaten amphipods and euphausiids, two groups of zooplanktonic organisms, represented 71-99% of the diet. The most frequent preys found in three of the four cruises corresponded to amphipods, represented by a single species, the hyperiid Themisto gaudichaudii, that accounted for over 50% of the food consumed. When depth of the catching area was beyond 100 m an increase in consumption of squid and fish by specimens above 20 cm ML was observed. No clear trends were found between the type of prey consumed and the time of catches or the degree of stomach repletion of the predator. The diet, of low diversity, showed that 56-62% of the squids studied fed on a single type of prey.
  • No Thumbnail Available
    Item
    Calamar argentino. Temporada 2024. Informe de situación al 16 de febrero (semana 7)
    (Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2024) Ivanovic, M.L.; Rossi, Gabriel R.; Prandoni, Nicolás I.; Mc Innes, Martha G.; Tapia Montagna, Tomás; Jacob, Julia M.
    Se presentan los resultados del seguimiento de la temporada de Illex argentinus desde el 2 de enero hasta el 16 de febrero (semana 7). Se analizaron los datos disponibles de captura, esfuerzo, muestreo biológico y área de operación de la flota potera argentina. Además, se estimó el número de barcos de la flota potera extranjera que está operando dentro y fuera de la ZEE. La estructura poblacional de la captura se determinó a partir del muestreo biológico efectuado por asistentes de investigación pesquera (AIP) del INIDEP. Se contó con los partes de pesca semanales de 64 barcos poteros, que sumaron un total de 1.589 días de pesca y 43.981 t de captura (28 t día-1). La captura de la flota arrastrera fue de 8.618 t. En el área adyacente a la ZEE se estimó que operó hasta un máximo de 280 buques poteros extranjeros entre las semanas 1 y 6, mayoritariamente en el rectángulo 4560. Dentro de la ZEE se detectó la presencia de buques poteros extranjeros a partir del 4/2, cuyo número se estimó en 87 para la semana 6. Al comienzo de la temporada, al sur de 49°S y sobre la plataforma externa al este de 61°O no se registraron capturas de calamar argentino. En enero, la actividad se concentró sobre la plataforma intermedia entre los 44°S y 46°S, donde el 72% de la captura total del mes se produjo en los rectángulo 4462/4562 (20.314 t, 30 t día-1), en tanto que durante la primera quincena de febrero el rectángulo 4662 aportó el 62% de la captura total del mes (9.881 t; 34 t día-1). El análisis de la información provista por AIP a bordo de nueve mareas (142 muestras, 21.416 ejemplares) permitió conocer que el calamar pescado era de tamaño pequeño (LMmedio = 218 mm; PTmedio = 209 g), maduro y en reproducción, lo cual permitió identificarlo como correspondiente al stock Desovante de Verano. Se registraron muy buenos rendimientos semanales promedio entre las semanas 2 y 7 (23-36 t día-1) cuando la flota operó sobre este stock y las mayores capturas se registraron en el área 44-47°S/62-63°O.
  • No Thumbnail Available
    Item
    Calamares de importancia comercial en Argentina. Biología, distribución, pesquerías y muestreo biológico
    (Mar del Plata : JICA. Japan International Cooperation Agency. Instituto Nacional de Investigación y Desarrollo Pesquero INIDEP, 1999) Brunetti, N.E.; Ivanovic, M.L.; Sakai, M.
    An overview of the available information on the commercially important squid species distributed in the Argentine Sea and adjacent zones is given. It includes the most representative characteristics to identify the species and general information on their biology, distribution and fisheries. A biological sampling designis presented, with particular emphasis on the identification of sexual maturity stages. The world market of the squid resources has considerably risen in the last decades and one of the most important fishery zones is placed in the Southwest Atlantic region (Area 41, FAO), where squid represent 25. of the total landings. Illex argentinus, sustains the second fishery in volume, with landings reaching 612.000 tonnes in 1999. Other species, such as Loligo sanpaulensis, Loligo gahi and Martialia hyadesi, are supporting small domestic fisheries. Also included is the current knowledge on Ommastrephes bartrami and Thysanoteuthis rhombus, cosmopolitan species that sustain important fisheries in other regions, and could be fishery exploitably alternatives here. A special case is that of Moroteuthis ingens, a worldwide particularly abundant species, but whose exploitation has been not developed yet. Finally, the giant squid (Architeuthis sp.)is included, as it started to appear frequently in this region during the last years and its knowledge is of high scientific value.
  • No Thumbnail Available
    Item
    Diet of red squid (Ommastrephes bartramii) in the Southwest Atlantic
    (2004) Ivanovic, M.L.; Brunetti, N.E.
    The diet of red squid (Ommastrephes bartramii) during autumn 2001 and 2002 in the SW Atlantic region off Argentina and Uruguay (33° S-42° S;46° W-55° W) was composed mainly of fish (55-68%), followed by squid (32-37%) and zooplankton (8% only in 2001). Around 60% of the fish eaten was identified as myctophids and corresponded to five genera and seven species, with higher frequency of Hygophum hygomii (24-34%). The identification of squids consumed reached 20% in 2001 and 80% in 2002 and the only species identified was O. bartramii, which implies percentages of cannibalism of 5.6% and 25.8% each year. For the range analyzed, 141-443 mm of mantle length (ML), the consumption of fish and squid did not show any relation to the size of predator. In 2001 the presence of zooplankton wasrestricted to individuals smaller than 300 mm ML. The diversity of diet was low and stomachs with a single type of prey predominated both years 59% in 2001, 92% in 2002
  • No Thumbnail Available
    Item
    Reproductive biology of red squid (Ommastrephes bartramii) in the Southwest Atlantic
    (Mar del Plata : Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), 2006) Brunetti, N.E.; Ivanovic, M.L.; Aubone, Aníbal; Pascual, L.N.
    Red squid (Ommastrephes bartramii) samples were collected during six exploratory cruises carried out in the Southwest Atlantic region off Argentina and Uruguay (33° S-42° S; 43° W-55° W) during summer-autumn of the period 1997-2002 on board the japanese jigger “Shinko Maru N° 3” under a joint research programme approved by Japan and Argentina. Size ranges of the squids analyzed were 10-40 cm mantle length (ML) for males and 12-49 cm ML for females. Two groups of squids were identified: smaller and larger than 20 cm ML. The group under 20 cm ML was characterized by the presence of immature squids and a sex ratio of around 1:1 in the whole study area. The squids of more than 20 cm ML included from immature to mature individuals. The mean sizes, proportion of mature individuals and proportion of males within this group increased northwards. Mature individuals were captured north of 39°S. The size and weight at 50% maturity were estimated at 30.48 cm ML and 852.95 g body weight (BW) for males and 42.30 cm ML and 2,287.18 g BW for females. The growth in weight of the reproductive system in both sexes was slow until the onset of maturity (males: 27-32 cm LM; females: 37-45 cm LM). The quantitative indices of maturity based on gravimetric measurements of the reproductive system structures showed that in both sexes the reproductive system total weight (RSW) represented less than 1% of BW by the onset of maturity. Then, the growth of the reproductive system accelerated, with RSW reaching 5% of male BW and 8% of female BW by the end of maturity.