Coralligenous bioconstructions are among the most important Mediterranean habitats for biodiversity maintenance. However some characteristic and sensitive organisms, such as the fan corals, are considered endangered in the international community; indeed, they may be severely damaged by fishing activities causing mechanical damage and increasing sedimentation rate. ROV (Remotely Operated Vehicle) investigations were carried out in order to characterize different morphological types of coralligenous habitat (rim, bank and shoal) located in the southern Bay of Naples (Italy), and to assess the presence of lost fishing gears and their impact on these benthic communities. A rapid classification of different fishing pressures and impacts was obtained through the development of new, representative and synthetic categories. Image analysis revealed the presence of rich and diversified communities, characterized by several fan coral colonies. However, fishing activity dramatically affects these coralligenous habitats, entangling and covering benthic assemblages and leading to necrosis and to parasitic epibionts growth especially on branched organisms. Monitoring programmes may provide a detailed assessment of coralligenous habitats characterization, distribution and health status. An accurate evaluation of fishing pressure and impact may be considered a useful tool to improve sustainable management of these valuable habitats.

Fisheries bycatches and discards constitute a significant problem in many fisheries worldwide. Unlike the pelagic purse-seine, the demersal purse seine usually targets high commercial value demersal species such as sea breams (e.g., Diplodus spp., Pagellus spp., Sparusaurata) and the European sea bass (Dicentrarchuslabrax), while discards consist mainly of pelagic species and juveniles of the above mentioned species. In order to evaluate the efficiency of a selectivity device in reducing bycatch and consequently of discards in a demersal purse seine fishery, experimental deployments were carried out. The bycatch reducing device (BRD) consisted in the use of a panel of diamond-shaped mesh netting of 70 mm stretched mesh in the posterior part of the purse seine. Data from 61 experimental fishing trials allowed the evaluation of discards, with Scomberjaponicus, Boops boops, Sardina pilchardus, Diplodus bellottii and Belone belone being the main discarded species. The mean discard ratio per set was 0.49 (± 0.30 standard deviation). The causes for discarding were also identified, with low commercial value being the most important reason. The results of the trials with BRD, were promising, with an average of 49% (± 24%) of the fish escaping per set, especially from those species that are most discarded. Overall, the use of this method for reducing discards can be considered positive for the following reasons: there is no need for structural modification of the fishing gear, the BRD is easy to deploy, and it is efficient in terms of species, sizes and quantities of fish that manage to escape. It therefore has significant benefits for the demersal purse seine fishery and possibly for other “métiers” as well.

The necessity to move from a traditional fishery management to an ecosystem approach is now acknowledged. Indicators are required to support the development of this approach. For example, community indicators have been proposed to assess the impact of fishing. We tested here the applicability of one such community indicator, the abundance-biomass comparison (ABC method), as a measure of the impact of bottom trawling (years of sampling: 2001 and 2003) on the benthic invertebrates – typically starfishes, crabs, squat lobsters, shrimps and large hard-shelled molluscs- of “Grande Vasière”, a major French fishing zone, in the Bay of Biscay. The ABC method is generally used as an impact indicator for different types of physical, biological and anthropogenic disturbances on benthic communities. This method is based on the assumption that increasing disturbance shifts communities from dominance by large-bodied species with low turnover rates toward dominance by small-bodied species with high turnover rates. At less disturbed areas the average biomass of individuals is greater than at more heavily disturbed areas. The ABC method measures this effect by comparing the ranked distributions of abundance and biomass within a given community. We applied the ABC method and compared the size structure and the species diversity at two areas exposed to moderate and high bottom trawl effort. Species diversity was lower in the most exploited area. The highly trawled area was dominated by opportunistic organisms, mainly one species of swimming crab Liocarcinus depurator, one species of squat lobster Munida rugosa and Norway lobsters Nephrops norvegicus, which are large-bodied species. Consequently, the results of the ABC method were inconsistent with the theoretical expectation for these particular macrofaunal communities and the measured levels of fishing intensity. 


Marine Protected Areas (MPA) are often contemplated as a tool for the sustainable management of exploited resources and ecosystem conservation. This paper proposes an approach to establish a statistical diagnostic of the effects of MPAs on fish assemblages, and define corresponding ecological indicators. This requires choosing relevant variables (abundance, diversity, demographic parameters ...) and appropriate statistical methods. The study was based on data from the Abore reef Reserve in New Caledonia. Two sets of methods: 1-inferential linear models (ANOVA, GLM); 2- Partial Least Squares (PLS) methods of regression, were used to test the effects of this MPA. PLS enabled us to test simultaneously within a model, density, species richness, biomass and mean size variables of fish community to retain the most sensitive and relevant ones. Habitat variability was also taken into account in these models. Species were grouped according to several criteria: 1- feeding habit; 2- taxonomy; 3- mobility; 4- adult size; 5- demographic strategy. No significant effect of the opening of the Abore reef to fishing was found for mobility. Feeding habit was the only criterion for which the results from the inferential models and PLS showed a significant effect of reserve status for all variables. Species richness, density, and to a lesser extent mean size, were sensitive to the removal of reserve status, but not biomass. Results from ANOVA and PLS regression were consistent but the latter allows a more holistic approach as it integrates all variables within a single model.