The research performed was aimed at assessment of fishing fleet impact upon krill population during the months (December-March), being critical to dependent species. The results of fishing intensity estimation are presented on the basis of haul to haul commercial statistics for Russian fleet (data of 2900 trawlings are used) in the South Orkneys area during December 1989 - March 1990. In the above period total krill catch amounted to 88.9 thous. t which constitutes the upper limit of seasonal fishing intensity (2.7 - 88.9 thous.t) obtained for above mentioned four months in 1984-1993 (CCAMLR, 1994). Therefore, the months critical to dependent species (December - March) during 1989/90) were considered as the months of the highest fleet pressure for entire period from 1984 to 1993. Krill fishery was concentrated in the area off the northern Coronation Island. Vessels of PPR type obtained the highest catch. During the period considered average monthly catch per trawling (Q) of those vessels was at the level of 30 t. The highest variability was observed in trawlings duration (τ) and catch per trawling hour (q). Coefficients of variation of average monthly estimates of those parameters during the period considered amounted to: CV(Q)=5.7%, CV(τ)=46%, CV(q)=36.2%. During the fishery period (December 1989 - March 1990) fishing intensity in each month critical to dependent species exceeded no 1 0% of initial krill stock at beginning of each month over entire area of vessels operation. In the fishing grounds where most number of vessels operated, the above estimate exceeded no 15%. Taking in account the estimation method used, those values are considered to be the upper theoretically probable limit. Taking in account the major fishing ground location within a zone of krill regular recruitment, it may be assumed that competition between fishing fleet and dependent predators for krill resources in that area is insignificant, therefore, probable negative impact via trophic chain is low.
Número de documento:
Punto(s) de la agenda