Yemaya, No. 26, November 2007

Asia/ India - Restricting Lives and Livelihoods. North America/ Mexico - Empowering Agenda?. Africa/ South Africa - Aren’t We Missing Something?. Africa/ Zanzibar - Winning Strategies. Latin America/ Chile - No Equity without Gender Equity. South America/ Ecuador - Banning the Beach Seine. North America/ United States - Walking in Both Sets of Shoes.

Los Peces Argentinos de Agua Dulce: Iconografía

En el transcurso del año 2007 se cumplieron cuarenta años de la publicación de la obra Los peces argentinos de agua dulce de Raúl A. Ringuelet, Raúl H. Arámburu y Armonía Alonso de Arámburu, la que representó un hito dentro de la ictiología nacional y regional. Por este motivo, el Programa para el estudio y uso sustentable de la Biota Austral Probiota), como un modesto homenaje a sus autores, quiere rescatar parte de la misma, ya que su reedición total para nosotros es hoy un objetivo imposible de cumplir. Para ello, hemos elegido reproducir su iconografía la cuál esta compuesta de 10 láminas y 37 figuras cuyos autores fueron A. Alonso de Arámburu, Carmen Castellano, Irma Cicchini, María E. Costa, María L. Fuster, E. Maristany, Ana Thörmalen y Carlos. A. Tremouilles. En este documento se agrupan las láminas en una primera sección y posteriormente las figuras, para finalizar con un apéndice que contiene la lista de las especies mencionadas con su sistemática actualizada. Este es otro paso dirigido a la consolidación de nuestra disciplina, ya que manteniendo siempre el recuerdo vivo del pasado lograremos afianzar el presente, lo que nos permitirá planificar con fundamentos nuestro futuro. (PDF tiene 60 paginas.)

Keine überdurchschnittlichen Nachwuchsjahrgänge bei den Nutzfischen der Nordsee

In January/February 2001, Germany participated with “Walther Herwig III” in the International Bottom Trawl Survey (IBTS) of ICES by contributing 70 half hour tows with the Grande Ouverture Verticale Bottom Trawl (GOV), 78 hydrographic stations, and 88 catches with the Method-Isaac-Kidd net (MIK), mostly in the central and northern North Sea. In total, 368 fishing stations by means of the GOV were covered by the international fleet. Preliminary results indicate that only indices for herring, whiting, and – to some degree – haddock are in the long-term mean. In contrast, the index for cod gives reason to serious concern. In addition, indices for both mackerel and Norway pout do not show any signs for an increasing strength of these stocks. Oceanographic data show that in comparison with the data from 1995 onwards actual temperatures and salinities are in the normal range. However, mean water temperatures of this short period are about more than a half degree above the long-term means of the period 1961 to 1990.

Mehr Nachwuchs bei Nutzfischarten der Nordsee, ausser beim Kabeljau

Ninety-one half-hour tows with the Grande Ouverture Verticale bottom trawl (GOV), 111 hydrographic stations and 100 catches with the Methot-Isaac-Kidd Net (MIK) were this years’ contribution of “Walther Herwig III” to the IBTS in various areas of the North Sea. Preliminary results indicate that especially haddock and, to some extent, whiting and Norway pout generated an ample 1999 yearclass. Indices for herring are also well above last years’ index whereas the cod indices indicate no substantial improvement of the stock. Largest concentrations of herring larvae were found in Moray Firth and west of the Dogger Bank/The Gut area. Temperatures of the North Sea were found to be above the long term means: 1 Centigrade on the open sea and up to 3 Centigrades in coastal areas. This years’ “WH III” IBTS activities at sea were considerably hampered by rough weather

Life cycle and biological parameters of several Brazilian Amazon fish species

This contribution summarizes knowledge on the biology (population dynamics, reproduction, ecology) of 25 fish species from the Lower Amazon, Brazil, based on data from a Brazilian-German field project (IARA) and a review of the literature.

Life history and population dynamics of the finetooth shark (Carcharhinus isodon) in the northeastern Gulf of Mexico

The life history and population dynamics of the finetooth shark (Carcharhinus isodon) in the north-eastern Gulf of Mexico were studied by determining age, growth, size-at-maturity, natural mortality, productivity, and elasticity of vital rates of the population. The von Bertalanffy growth model was estimated as Lt=1559 mm TL (1–e–0.24 (t+2.07)) for females and Lt = 1337 mm TL (1–e–0.41 (t+1.39)) for males. For comparison, the Fabens growth equation was also fitted separately to observed size-at-age data, and the fits to the data were found to be similar. The oldest aged specimens were 8.0 and 8.1 yr, and theoretical longevity estimates were 14.4 and 8.5 yr for females and males, respectively. Median length at maturity was 1187 and 1230 mm TL, equivalent to 3.9 and 4.3 yr for males and females, respectively. Two scenarios, based on the results of the two equations used to describe growth, were considered for population modeling and the results were similar. Annual rates of survivorship estimated through five methods ranged from 0.850/yr to 0.607/yr for scenario 1 and from 0.840/yr to 0.590/yr for scenario 2. Productivities were 0.041/yr for scenario 1 and 0.038/yr for scenario 2 when the population level that produces maximum sustain-able yield is assumed to occur at an instantaneous total mortality rate (Z) equaling 1.5 M, and were 0.071/yr and 0.067/yr, when Z=2 M for scenario 1 and 2, respectively. Mean generation time was 6.96 yr and 6.34 yr for scenarios 1 and 2, respectively. Elasticities calculated through simulation of Leslie matrices averaged 12.6% (12.1% for scenario 2) for fertility, 47.7% (46.2% for scenario 2) for juvenile survival, and 39.7% (41.6% for scenario 2) for adult survival. In all, the finetooth shark exhibits life-history and population characteristics intermediate to those of sharks in the small coastal complex and those from some large coastal species, such as the blacktip shark (Carcharhinus limbatus).