Spatial patterns of demersal communities from bottom trawl on the Portuguese North Coast (continental shelf)

Abstract Understanding the diversity and community composition of marine communities in coastal areas is of utmost importance to understand how overlapping anthropogenic pressures impact the marine environment. The demersal and epibenthic communities of the Portuguese northern continental shelf were surveyed using a bottom trawl to understand their taxonomic composition, abundance, spatial distribution, and their relationship with environmental variables such as sediment, organic matter, depth and latitude. Bottom sediments were homogenous, being mainly composed by sand particles. The diversity of the study area was low, but high abundance of important commercial species, as Trisopterus luscus, Trachurus trachurus, Palaemon serratus and Merluccius merluccius, in the juvenile stage of life, points out the importance of the area as nursery grounds. Four assemblages were identified, with a visible geographical pattern. Results obtained supply background information that may contribute to the development of future management and monitoring plans for this important and sensible coastal area.