Genetic diversity and connectivity remain high in Holothuria polii (Delle Chiaje 1823) across a coastal lagoon-open sea environmental gradient

Coastal lagoons represent habitats with widely heterogeneous environmental conditions, particularly as regards salinity and temperature,which fluctuate in both space and time. These characteristics suggest that physical and ecological factors could contribute to the genetic divergence among populations occurring in coastal lagoon and opencoast environments. This study investigates the genetic structure of Holothuria polii at a micro-geographic scale across theMar Menor coastal lagoon and nearbymarine areas, estimating the mitochondrial DNA variation in two gene fragments, cytochrome oxidase I (COI) and 16S rRNA (16S). Dataset of mitochondrial sequences was also used to test the influence of environmental differences between coastal lagoon andmarine waters on population genetic structure. All sampled locations exhibited high levels of haplotype diversity and low values of nucleotide diversity. Both genes showed contrasting signals of genetic differentiation (non-significant differences using COI and slight differences using 16S, which could due to different mutation rates or to differential number of exclusive haplotypes. We detected an excess of recent mutations and exclusive haplotypes, which can be generated as a result of population growth. However, selective processes can be also acting on the gene markers used; highly significant generalized additive models have been obtained considering genetic data from16S gene and independent variables such as temperature and salinity.

The EU landing obligation and European small-scale fisheries: What are the odds for success?

A landing obligation was formally implemented in the European Union (EU) for the first time, as part of the recent reform of the EU Common Fisheries Policy (CFP). Given the reasonable success of the landing obligation in some countries such as the Faroe Islands, Iceland and Norway, this policy is seen as a viable approach to tackle the long-recognized discarding problem in EU waters. However, there has been some debate on whether there is sufficient evidence to support the feasibility of such a measure in the EU-CFP. The EU landing obligation will implicitly include all small-scale fisheries (SSF) provided the species captured are subject to catch limits or minimum sizes (in the case of the Mediterranean). SSF were included irrespective of the fact that the discarding problem in the EU has been historically associated with medium- to large-scale fleets (in particular largely mixed species trawl fisheries). Additionally, past experiences with a discard ban policy are still limited to specific countries and/or specific fisheries. This paper examined the appropriateness and feasibility of the recently implemented EU landing obligation in SSF. The effects in the long-term are unpredictable, but available evidence suggests that in the short to medium-term a landing obligation is likely to bring more negative social, economic and ecological impacts than benefits. (C) 2015 Elsevier Ltd. All rights reserved.

Toward adaptive management of coastal MPAs: The influence of different conservation targets and costs on the design of no-take areas

There is still much discussion on the most appropriate location, size and shape of marine protected areas (MPAs). These three factors were analyzed for a small coastal MPA, the Luiz Saldanha Marine Park (LSMP), for which a very limited amount of local ecological information was available when implemented in 1998. Marxan was used to provide a number of near-optimal solutions considering different levels of protection for the various conservation features and different costs. These solutions were compared with the existing no-take area of the LSMP. Information on 11 habitat types and distribution models for 3 of the most important species for the local artisanal fisheries was considered. The human activities with the highest economic and ecological impact in the study area (commercial and recreational fishing and scuba diving) were used as costs. The results show that the existing no-take area is actually located in the best area. However, the no-take area offers limited protection to vagile fish and covers a very small proportion of some of the available habitats. An increase in the conservation targets led to an increase in the number of no-take areas. The comparative framework used in this study can be applied elsewhere, providing relevant information to local stakeholders and managers in order to proceed with adaptive management. (C) 2015 Elsevier B.V. All rights reserved.

Trophic food web and ecosystem attributes of a water reservoir of the Ria Formosa (south Portugal)

Using a top-down modelling approach, a balanced trophic food web model of a water reservoir of the Ria Formosa lagoonal system was constructed. Few adjustments of input data were necessary to run the model since most of the parameters were estimated at the study site and the characteristics of the water reservoir allowed a high degree of control and precision in terms of sampling and data collection. Trophic levels of the 14 compartments included in the model varied between 1.0 for primary producers and detritus to 3.4 for carnivorous fish and the 14 groups were aggregated in a food chain with six trophic levels. The water reservoir has a detritus based food chain, with the majority of the biomass concentrated in the first two levels, the producers level and the herbivore/detritivore level (97.6%). The transfer efficiencies were low, and decreased with increasing level number, varying between 6.0 and 0.2%. The degree of "ecosystem maturity" was difficult to establish, but several parameters indicate that it could be high. The water reservoir studied, which has similar environmental and ecological characteristics as the Ria Formosa lagoon. is near its carrying capacity. (C) 2004, Elsevier B.V. All rights reserved.