New Zealand Mid-water or incidental New Zealand 2001/2002 High Geographical area Out of a total of 55 dolphin (Du Fresne et bottom trawling mortalities of fisheries (represented by captures, 42 occurred at fishing al., 2007) 2004/2005 But low for the common dolphin observers FMAs) had the most depths equal to or less than 115 m. fishing % See text for commercial fish (Delphinus delphis) influence on A further 9 occurred at fishing Observer years coverage New Zealand species jack dolphin bycatch. All depths between 115 m and 184 m. coverage (i.e. for more info. (i.e. 01 mackerel observed bycatch Total winch time was the next most the October (Trachurus events occurred in important factor, with the bycatch percentage of 2001 to 30 novaezelandiae) three out of eight occurring when total winch time tows September Fisheries exceeded 24 min. Covering six observed) 2005) Management Areas. Fisheries ranged from Using classification Management 4% to 27%. tree analysis Areas (FMAs) important predictors of bycatch were: fishing depth, total winch time and light conditions. Most dolphin captures occurred during mid-water trawls, and predominantly during dark conditions of little or no moonlight.
New Zealand Mid-water or bottom trawling for the commercial fish species jack mackerel (Trachurus novaezelandiae) Covering six Fisheries Management Areas (FMAs) incidental mortalities of common dolphin (Delphinus delphis) New Zealand fisheries observers Observer coverage (i.e. the percentage of tows observed) ranged from 4% to 27%. 2001/2002 2004/2005 fishing years (i.e. 01 October 2001 to 30 September 2005) High But low % coverage Geographical area (represented by FMAs) had the most influence on dolphin bycatch. All observed bycatch events occurred in three out of eight Fisheries Management Areas. Using classification tree analysis important predictors of bycatch were: fishing depth, total winch time and light conditions. Most dolphin captures occurred during mid-water trawls, and predominantly during dark conditions of little or no moonlight. Out of a total of 55 dolphin captures, 42 occurred at fishing depths equal to or less than 115 m. A further 9 occurred at fishing depths between 115 m and 184 m. Total winch time was the next most important factor, with the bycatch occurring when total winch time exceeded 24 min. (Du Fresne et al., 2007) See text for New Zealand for more info.
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