1)Sociedade Portuguesa de Vida Selvagem, Universidade do Minho, Dep Biologia, Campus de Gualtar, , Braga, Portugal 2) Centre for Environmental and Marine Studies (CESAM), Dep Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal 3) Instituto Nacional de Recursos Biológicos, IPIMAR-Matosinhos, Avenida General Norton de Matos, 4, , Matosinhos, Portugal 4) CBMA/Dep. Biologia, Universidade do Minho, Campus de Gualtar, , Braga, Portugal 5) Instituto Nacional de Recursos Biológicos, IPIMAR-Algés, Avenida De Brasília, , Lisboa, Portugal Ana Marçalo 1,2, Diana Feijó 3, Marisa Ferreira 1,4, Hélder Araújo 1,4, Jorge Santos 1,4, Isabel Oliveira 1,4, Silvia Monteiro 1,4, Joana Miodinski 1,4, Yorgos Stratoudakis 5, José Vingada 1,2,4 In Portugal, purse seining is a very important fishery responsable for the capture of about 50 % of all fish landings in continental waters, mainly small pelagics. Recently, this fishery, which targets Atlantic sardines (Sardina pilchardus) obtained the Marine Stewardship Council certification in which one of the conditions was the impact on ETP species. Four of the 19 species of cetaceans found in Portuguese continental waters overlap with the sardine purse seine fishery: Phocoena phocoena; Delphinus delphis; Tursiops truncatus; and Balaenoptera acutorostrata. Up to now, the only information on cetacean interactions with the Portuguese purse seine sardine fishery comes from a 3 month study on the Northwestern coast (Wise et al., 2003). In the present study, the area and period of observation was expanded and complemented with interviews in order to obtain an improved characterization of cetacean interactions with the fishery along the Portuguese continental coast. Introduction Materials and Methods Onboard observation work: From January to November 2010, observers monitored over 40 fishing trips in different ports along the Portuguese continental coast. The total catch biomass and species composition per fishing set was recorded. Fishing effort was calculated as the sum of the time spent searching and fishing per fishing trip, as both affect catch rates (Wise et al. 2003). The catch-per-unit effort (CPUE) was calculated as the catch biomass per unit of fishing effort. Fishing effort and CPUE were compared among fishing trips carried out in the presence and absence of cetaceans using a Kruskal-Wallis test. Only data from the southern region (Sines, Olhão and Portimão) was analyzed as the majority of fishing events attended by cetaceans occurred in this region. Interview data : This at-sea work was complemented by an interview survey carried out in the most important Portuguese harbors (Póvoa do Varzim, Matosinhos, Figueira da Foz, Peniche, Nazaré, Setúbal, Lagos, Portimão and Olhão) from 2008 and 2010 to purse seine skippers (covering > 70 % of the national fleet). Fig. 2: Boxplot of (A) fishing effort and of (B) CPUE of fishing trips without (NC) and with (WC) the presence of small cetaceans. Results and Discussion  Only Delphinus delphis was observed to interact with fishing activities, which most frequently occurred in the Southern coast (Table 1 & Fig 1). Mean fishing effort values decreased significantly (P< 0.05) in the presence of common dolphins while CPUE did not change significantly (Fig 2).  Fishermen in most cases are indifferent (mix of positive and negative feelings) about the impact of cetaceans on their activities, although the most frequently cited negative effect is that dolphins may reduce catches (disperse fish). In the fishery, most of the captured cetaceans are released alive and voluntary mitigation measures (steaming to other fishing grounds or wait before shooting) take place frequently.  Regional variability and seasonal fluctuations in the rate of interactions and accidental captures for the fishery requires increased and continued observation effort in order to attain better estimates of its impact. Fig. 1: Distribution of observed trips or fishing events with (o) or without (+) presence of small cetaceans. Enlarged is the South area used for the analysis. Table 1: Summary information of the monitored fishing trips off the Portuguese Coast; January-November Interview data from North Center South Observations of operational interactions between the Portuguese sardine purse seine fishery and cetaceans Area Trips SetsCatchFishing effortCPUE % OccurencesSpeciesInterviews (n) (ton)(mean) (n interactions/total n sets)interacting North & Center233263,73,74833,1Delphinus delphis64 South ,23, ,9Delphinus delphis29 Total ,9 93 H07 A B