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    Incidental mortality of seabirds associated with longline fishing in Subarea 48.3 – preliminary results of scientific observations onboard the Chilean longliner, Puerto Ballena, from March to May 1996

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    Selling, J., Kock, K.-H.
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    Estimates of the number of seabirds taken incidentally in longline fisheries on Patagonian toothfish (Dissostichus eleginoides) are still based on limited information. We report here on observations on the by-catch of seabirds during a cruise of the Chilean longliner 'Puerto Ballena' in Statistical Subarea 48.3. A total of 118 dead black-browed albatrosses, 3 dead grey-headed albatrosses, 46 dead white-chinned petrels were reported by the observer and crew members. In addition 21 black-browed albatrosses, 4 giant petrels, 1 white-chinned petrel and 1 unidentified penguin became hooked alive and were released alive. Our preliminary analysis confirmed results from last year that black-browed albatrosses are particularly at risk when longlines are set during the day and/or the streamer line is malfunctioning. If setting of lines had been restricted to nighttime as required in order to comply with Conservation Measure 29/XIV(CCAMLR, 1995) the number of black-browed albatrosses and white-chinned petrels taken incidentally would have been substantially lower. The by-catch of both black-browed albatrosses and white-chinned petrels appeared to decline towards the end of April/begriming of May. The estimated total catch for all observed sets was 312 black-browed albatrosses and 213 white-chinned petrels. This estimate should be regarded as tentative as there rue still problems associated with extrapolating observed numbers of dead seabirds from a subsample of hooks to the total number of hooks in a set which warrant further investigation. However, even if we consider the number of dead birds recorded by the observer and by crew members as a minimum estimate, these figures appear by far too high to be sustainable by both black-browed albatrosses and white-chinned petrel populations in the area.