The spatio-temporal pattern of hake (M. hubbsi) abundance and environmental influence in the Patagonian shelf area

The Argentine hake (Merluccius hubbsi) is one of the most important fishery resources in the Southwest Atlantic. This species is widely distributed in the Patagonian shelf area and it is a major target species by international fleets in this South West Atlantic area. This paper presents results on the spatio-temporal distribution pattern of hake M. hubbsi abundance and environmental influence in the Patagonian shelf area. Spanish commercial fisheries data from 1989 to 1999 were used in the analysis. Data were collected by observers deployed by the IEO, Vigo (Instituto Español de Oceanografía, Vigo). The data include 15343 fishing haul records. CPUE (Catch Per Unit Effort, kg⋅hr-1) was used as an abundance index. The analyses of the general spatio-temporal pattern of fish abundance, and the influence of environmental factors, such as SST, SBT, depth, moon phase and cloud cover, on fish abundance and distribution, were based on correlation, variograms, and timeseries maps created using GIS. Hake-targeted fishing by Spanish fleets was mainly focused on the shelf-edge area between 44.5°S – 47.0°S outside the Argentinean EEZ and in the area northwest of the Falkland Islands. The centre of high abundance is located in the shelf-edge area between 44.5°S – 47.0°S, particularly in the west part (i.e. in shallower waters) and in winter. The correlations between fish abundance and cloud cover are overwhelming negative, indicating that higher catches usually occur in cloudy weather conditions. In the major hake-targeted fishing area between 44.5°S – 47.0°S, the negative relationship between fish abundance and sea surface temperature in most months may suggest that high fish abundance is related to the strong northward cold Falklands current, and abundance is positively related to sea depth in summer.