BECAS
GÓNGORA MarÍa Eva
informe técnico
Título:
Estimation of mortality and preliminary analysis of seabird bycatch in bottom and midwater trawlers in Argentina.
Autor/es:
TAMINI, LEANDRO LUIS; CHAVEZ, LEANDRO NAHUEL; DELLACASA RUBÉN; GÓNGORA MARÍA EVA; CRAWFORD RORY; FRERE ESTEBAN
Fecha inicio/fin:
2019-01-01/2019-05-05
Páginas:
1-9
Naturaleza de la
Producción Tecnológica:
Pesquera
Campo de Aplicación:
Recursos naturales renovables-Varios
Descripción:
We studied the seabird mortality associated with factory trawl vessels using both bottom and midwater trawls to target Hoki (Macruronus magellanicus), Southern Blue Whiting (Micromesistius australis) and Patagonian Toothfish (Dissostichus eleginoides) along the south tip of the Argentine Patagonian Shelf from 2012 to 2017. We tested the efficacy of bird scaring lines (BSLs) as a mitigation measure to reduce seabird mortality on trawl warp and net monitoring cables. Across 650 days and 1839 hauls, Albatross Task Force instructors recorded three types of seabird interactions: entanglements with the trawl net; collisions with warps and collisions with net monitoring cables. In addition, we recorded the numbers of seabirds killed and hauled aboard. The main species affected by collisions from warp and net monitoring cables were Cape Petrel (Daption capense), Black-browed Albatross (Thalassarche melanophris, BBA), Southern Giant Petrel (Macronectes giganteus, SGP), followed by Southern Royal Albatross (Diomedea epomophora; SRA), Grey-headed Albatross (T. chrysostoma) and Northern Giant Petrel (M. halli). A total of 165 BBA, 27 SGP and 16 SRA corpses were recovered from net entanglements and warp/net monitoring cable collisions, resulting in confirmed mortality rates of 0.09 birds/haul of BBA, 0.015 birds/haul of SGP and 0.0087 birds/haul of SRA primarily occurring through collisions with the net monitoring cable (87.8%). Estimations of fishery-wide mortality indicate that 83 [31-145] SRA and 310 [159-486] BBA are killed annually through net monitoring cable collisions. The use of BSLs resulted in a significant decline in the number of collisions with both cables, with a combination of no discarding and BSLs use reducing interactions to c. zero.
