MONITORING OF SEWAGE OUTFALLS IN NORTHERN SPAIN - PRELIMINARY STUDIESOF BENTHIC COMMUNITIES

Baseline studies constitute, at the same time, the base and the refere nce point for the development of site-specific monitoring programs. As a previous step in the analysis of the structure of benthic communiti es in the infralitoral off Aviles and Gijon, multivariate techniques w ere used to assess the agreement between the distribution pattern of s amples, from both rocky and soft bottom benthos, according to their sp ecies or family compositions. Sampling was carried out in summer 1992. Stations were located on a depth gradient basis (A: -1 m; B: -5 m; C: -15 m; D: -25 m; E: -35 m; F: -45 m) along eight transect lines. Abun dance data from replicate samples from each station, aggregated at bot h the species and the family levels, were tested by three complementar y multivariate measures of community structure: clustering (CL), princ ipal components analyses (PCA) and multidimensional scaling (MDS) tech niques. The main results obtained in this study demonstrated the adequ acy of family-based abundance data for carrying out classification and ordination of samples from both rocky and soft bottom benthic ecosyst ems.