Browsing by Author "Santos, Miguel Neves dos"
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- Comparative behavior of wild and hatchery reared white sea bream (Diplodus sargus) released on artificial reefs off the Algarve (Southern Portugal)Publication . Lino, Pedro; Bentes, Luis; Abecasis, D.; Santos, Miguel Neves dos; Erzini, KarimThree hatchery produced and reared (HPR) and five wild white sea bream (Diplodus sargus) were double tagged with Vemco V8SC-2L acoustic transmitters and Floy Tag T-bar anchor tags, and released on artificial reefs located near a natural reef off the southern coast of Portugal. Passive telemetry was used to monitor movements of the white sea bream over a nine week period from April to June 2007. Differences in behavior at release, habitat association (artificial vs. natural reef), and in daily movements were registered. Wild fish moved from one habitat to the other with increased preference for the artificial habitat during the day, whereas HPR fish showed no site fidelity or consistent daily movement pattern and left the release site soon after release. Comparison of Minimum Convex Polygon (MCP) showed a higher area usage by wild fish. This experiment shows that these artificial reefs are used on a daily basis by wild white sea bream but apparently are not optimal release locations for hatchery produced white sea bream.
- Stakeholders' conceptualization of offshore aquaculture and small-scale fisheries interactions using a Bayesian approachPublication . Ramos, Jorge; Caetano, Miguel; Himes-Cornell, Amber; Santos, Miguel Neves dosRecent coastal planning measures in south-east Portugal (Algarve), where offshore aquaculture developments were set up in fishing areas aiming to maximize expected utility of seafood production activities, raised some discontentment. Public policies created to safeguard offshore aquaculture (OSA) producers and limit small-scale fishing (SSF) activities must be adjusted accordingly in order to maximize income and keep discontentment at a minimum. We collected primary data from stakeholders, fishers (n = 18) and offshore aquaculture operators (n = 3) through participatory workshops and interviews by eliciting problematic issues derived from the offshore area creation and their relative relevance. We used these data to populate conditional probability tables and construct a related influence diagram (Bayesian belief networks) to model the affected system. We selected nine scenarios based on navigability and aquaculture area size with the aim of finding the best expected utility combinations for the OSA SSF system. The inferred results show that maximizing employment and keep pollution at low levels were the most influential factors to keep the system at a satisfactory level. The best decision was not to enlarge the aquaculture area, but to condition the access to other operational stakeholders, namely SSF operators from nearby areas. The overall results of the Bayesian belief network can be used to recommend coastal planners and decision-makers to deal with the interaction between OSA and SSF activities.(c) 2017 Elsevier Ltd. All rights reserved.