The impact of live bait harvesting in the macrobenthic community of a coastal lagoon – Preliminary results
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1
School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, MARE - Marine and Environmental Sciences Centre, Portugal
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2
Department of Life Science, University of Coimbra, Centre for Functional Ecology, Portugal
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3
Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, MARE – Marine and Environmental Sciences Centre, Portugal
Coastal lagoons support important ecological functions and services, however these systems have been subjected to human induced impacts, such as chemical contamination, habitat loss and overexploitation of natural resources. Among these, live bait harvesting has been suggested to compromise the ecological integrity of coastal ecosystems. Evaluate the effects of those impacts is, therefore, necessary and urgent, in order to define protective measures to preserve areas of high ecological value. Despite that live bait harvesting does not take intensive proportions in the Óbidos Lagoon (center of the western coast of Portugal), some episodes of this activity were observed in May and June of 2010. Thus, this study aimed to evaluate the environmental impact of live bait harvesting (specifically of the ragworm Hediste diversicolor) in the macrobenthic intertidal community. From April to July 2010, sediment samples were monthly collected at the site Covão dos Musaranhos (Óbidos Lagoon, Bom Sucesso branch: 39º 23.280´ N; 009º 13.565´ W), to assess the macrobenthic communities’ structure, both qualitatively and quantitatively. Abundance, density, species composition and diversity indexes (Margalef, Shannon-Wiener, Pielou Evenness and Simpson) of the community were evaluated, before and after the harvesting events. Three species revealed to be dominant: Hediste diversicolor, Cyathura carinata and Cerastoderma edule. According to the preliminary results, the number of species of the community and the density of the classes Gastropoda and Polychaeta decreased after the harvesting events. A decline in the density of H. diversicolor, the target species from the catches in 2010, was observed as well (1257 ind.m-2 before the impacts as opposed to 708 ind.m-2 after the impacts). Also, Margalef and Shannon-Wiener indexes decreased after the impacts, while the index of Simpson showed the opposite trend. In conclusion, harvesting polychaetes in the Óbidos Lagoon may contribute to the unbalance of this ecosystem, as it affects the structure of the biological communities. Although this is not a common practice at the study site, bait harvesting at the Óbidos Lagoon should be avoided, if the ecological integrity of these communities is to be preserved. Also, in estuarine areas where this practice is usual, the ecological status of the macrobenthic communities should be regularly assessed and monitored, and the intensity of live bait harvesting accordingly adjusted.
Keywords:
Óbidos Lagoon,
Bait harvesting,
intertidal macrobenthic communities,
Hediste diversicolor,
Environmental impact
Conference:
IMMR | International Meeting on Marine Research 2016, Peniche, Portugal, 14 Jul - 15 Jul, 2016.
Presentation Type:
Poster presentation
Topic:
Biodiversity, Conservation and Coastal Management
Citation:
Catarino
M,
Pedro
CA,
Baptista
T,
Pombo
A,
Ferreira
S and
Gonçalves
SC
(2016). The impact of live bait harvesting in the macrobenthic community of a coastal lagoon – Preliminary results.
Front. Mar. Sci.
Conference Abstract:
IMMR | International Meeting on Marine Research 2016.
doi: 10.3389/conf.FMARS.2016.04.00081
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Received:
20 Apr 2016;
Published Online:
13 Jul 2016.
*
Correspondence:
Prof. Sílvia C Gonçalves, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, MARE - Marine and Environmental Sciences Centre, Peniche, 2520-641, Portugal, scgoncalves@ipleiria.pt