En este trabajo, se reunió la información de mortalidad incidental de aves marinas ocurridas en los buques argentinos y chilenos que operaron en la temporada de pesca del Dissostichus eleginoides en la subarea 48.3 entre el 1 de marzo y el 16 de mayo de 1995. Los datos tienen su origen en los informes de escala fina entregados por los capitanes de las naves a las autoridades pesqueras de ambos paises y en los informes presentados por los Observadores Científicos. De esta manera, se pudo evaluar cerca del 100 % de la mortalidad ocurrida durante la temporada. Se encontró una mortalidad total de 954 aves, cuyo 69% es Procelaria aequinoctialis, seguida por Phoebetria fusca ( 13%), Macronectes .giganteus (8%), Diomedea melanophris (4%)) Diomedea epomophora (3%) y Diomedea exulans (0,3%). También se registro un total de 537 aves capturadas durante los virados y liberadas vivas, entre las cuales dominaron Phoebetria fusca ( 61 %) y Macronectes giganteus ( 18 %). Se estudiaron las variables que podrían afectar esta mortalidad encontrándose que: 1) la distancia a las islas , 2) el ciclo lunar ( ya que la casi totalidad de los lances fueron nocturnos) 3) el uso de las lineas espantapájaros y 4) el tamaño de los anzuelos, son importantes fuentes de variación tanto en el análisis global BPUE por barco como en escala de lance por lance.

This paper presents a flexible structure for a general yield model, which provides flexibility for assessing the influence of different patterns of growth, natural mortality, spawning and fishing on the estimates of yield per recruit. Also, it can be used to evaluate the performance of a stock under a specified catch regime. The model uses an adaptive Runge-Kutta procedure to evaluate stock trajectories and catch rates over a simulation period. In particular, this procedure calculates catches over each year by integrating a set of differential equations which incorporate functions that specify the rate of change or magnitude of parameters, such as growth, mortality, age dependent selectivity and seasonal patterns in fishing mortality, at specified time intervals during the year. This general approach also includes an option for a stock to experience a known catch history before the constant catch regime is introduced.

The survey comprised 48 bottom trawl hauls taken in subarea 48.3. About 80% of the hauls were intended as replicates of the position of hauls in the 1994 survey, allowing site by site comparison between both cruises. Of these, 20 hauls were located at less than 0.5 miles and 11 between 0.5 and 1.0 miles from those in the previous survey. Mean densities were obtained considering the spatial aggregation of stations in a nested ANOVA model. An increase over last year's values was observed in the density of several species, particularly Champsocephalus gunnari at the shelf of the South Georgia Islands. The age and size structure of this species in the whole subarea 48.3 is characterized the predominance of the younger fraction (below 4 years: 99.3% at the South Georgia Islands and 93.4 % at Shag Rocks). Along the cruise, 128 oceanographical stations were occupied. Oceanographical conditions were largely within the historical limits except for a the possible presence of a large eddy in the northern part of the Scotia Sea. Plankton samples contained krill more often than last year and an hydroacoustical survey for krill which covered a total of 800 nautical miles in the South Georgia shelf has shown the presence of krill aggregations in larger quantities than in last years survey.