The Ecosystem Approach to Fisheries: Issues, Terminology, Principles, Institutional Foundations, Implementation and Outlook

Ecosystems are complex and dynamic natural units that produce goods and services beyond those of benefit to fisheries. Because fisheries have a direct impact on the ecosystem, which is also impacted by other human activities, they need to be managed in an ecosystem context. The meaning of the terms 'ecosystem management', 'ecosystem based management', 'ecosystem approach to fisheries'(EAF), etc., are still not universally defined and progressively evolving. The justification of EAF is evident in the characteristics of an exploited ecosystem and the impacts resulting from fisheries and other activities. The rich set of international agreements of relevance to EAF contains a large number of principles and conceptual objectives. Both provide a fundamental guidance and a significant challenge for the implementation of EAF. The available international instruments also provide the institutional foundations for EAF. The FAO Code of Conduct for Responsible Fisheries is particularly important in this respect and contains provisions for practically all aspects of the approach. One major difficulty in defining EAF lies precisely in turning the available concepts and principles into operational objectives from which an EAF management plan would more easily be developed. The paper discusses these together with the types of action needed to achieve them. Experience in EAF implementation is still limited but some issues are already apparent, e.g. in added complexity, insufficient capacity, slow implementation, need for a pragmatic approach, etc. It is argued, in conclusion, that the future of EAF and fisheries depends on the way in which the two fundamental concepts of fisheries management and ecosystem management, and their respective stakeholders, will join efforts or collide

Nursery Habitat and Diet of Juvenile Centropomus Species in Puerto Rico Estuaries

The distribution of the early stages of five species of Centropomus was studied in Puerto Rico and varied among the estuarine areas sampled. Based on the collection of 4, 710 juvenile snook, the study showed that the most abundant species (standard length \u3c 50 mm) collected in river systems was C. parallelus (81%); in contrast, C. undecimalis (62%) and C. ensiferus (35%) were more abundant in lagoon systems. Colonization peaks of the three most abundant species showed broad overlapping: from June to Nov. for C. undecimalis, from July to Dec. for C. ensiferus, and from April to Nov. for C. parallelus. Preferred nursery habitats were turbid, calm waters in the vicinity of shelter (mangrove roots, grass, or water hyacinths). The physical parameter range of juvenile snook habitat was relatively broad: salinity from 0 to 30 ppt temperature from 24 to 35 C, and anoxic to well-oxygenated water. Condition factors of two size classes of snook (less than 100 mm and between 100 and 300 mm in standard length) showed no significant differences between river and lagoon systems or between seasons. Food habits were significantly different between species during the early stages (standard length \u3c 100 mm), but this difference was resolved when river and lagoon samples were studied separately. In the river system, C. undecimalis and C. ensiferus preyed primarily upon shrimp, whereas in the lagoon they fed mainly on fish

Organisation spatiale des peuplements ichtyologiques des herbiers à Thalassia du Grand Cul-de-Sac Marin en Guadeloupe

Les herbiers à #Thalassia testudinum du Grand Cul-de-Sac Marin en Guadeloupe ont fait l'objet d'une étude de la variabilité spatiale de la faune ichtyologique et de quelques paramètres de l'environnement (densité, biomasse et longueur foliaire, agitation, température, oxygène dissous, pH et salinité). Les échantillons de poissons ont été prélevés à la senne de plage dans 11 stations réparties de la côte (mangrove) à la barrière frangeante des récifs coralliens, pendant 12 mois consécutifs (août 1987 à juillet 1988). Les stations non significativement différentes (test de Kruskal-Wallis) pour la température ou le pH, le sont en revanche, pour la densité, la biomasse et la longueur des feuilles de #Thalassia, l'oxygène dissous et la salinité, ainsi que pour la richesse spécifique, la régularité et la biomasse ichtyologiqu

Microbial contamination and management scenarios in a Mediterranean coastal lagoon (Etang de Thau, France): application of a Decision Support System within the Integrated Coastal Zone Management context

1 - In the Thau lagoon (Southern Mediterranean Coast) the main anthropogenic pressure is represented by the urban development in the watershed, whilst oyster and mussel farming represents one of the main economical activities in the region. 2 - During the last decade, the increasing organic loads from watershed and urban settlements in the lagoon surroundings have caused a diffuse contamination by faecal bacteria. Also toxic algal blooms have been occurring, impairing water quality with major impacts on shellfish farming, fishery and bathing. 3 - In this study, indicators and scenarios identified for the lagoon have been integrated in a Decision Support System (DSS) to evaluate the best solutions for reducing pressures and improving both water quality and ecosystem status. 4 - The watershed has been analysed with reference to indicators of pollution sources and transfer rates to the lagoon. In parallel, socio-economic indicators and descriptors of urban growth and development have been assessed. Numerical models have been run in order to simulate the lagoon hydrodynamics in relation to both meteorological factors and watershed runoff. The impact of faecal bacteria contamination has been evaluated in terms of economical losses and social conflicts, arising from the restriction of shellfish farming and marketing during contamination events. Finally, the DSS prototype has been applied to the lagoon in support to management and future planning

Organisation spatiale des peuplements ichtyologiques des herbiers à Thalassia du Grand Cul-de-Sac Marin en Guadeloupe

Les herbiers à #Thalassia testudinum du Grand Cul-de-Sac Marin en Guadeloupe ont fait l'objet d'une étude de la variabilité spatiale de la faune ichtyologique et de quelques paramètres de l'environnement (densité, biomasse et longueur foliaire, agitation, température, oxygène dissous, pH et salinité). Les échantillons de poissons ont été prélevés à la senne de plage dans 11 stations réparties de la côte (mangrove) à la barrière frangeante des récifs coralliens, pendant 12 mois consécutifs (août 1987 à juillet 1988). Les stations non significativement différentes (test de Kruskal-Wallis) pour la température ou le pH, le sont en revanche, pour la densité, la biomasse et la longueur des feuilles de #Thalassia, l'oxygène dissous et la salinité, ainsi que pour la richesse spécifique, la régularité et la biomasse ichtyologiqu

Polyimide organic solvent nanofiltration membranes-formation and function

This thesis offers a comprehensive study that analyses the relationship between polyimide (PI) organic solvent nanofiltration (OSN) membrane formation parameters, membrane structure, and membrane functional performance. The dissertation starts by addressing the structure-related problem of macrovoid formation, which arises when more open membranes are prepared. Incorporation of TiO2 nanofillers into the membrane matrix results in macrovoid-free, organic/inorganic PI/TiO2 mixed matrix membranes without compromising rejection. Subsequently, a detailed analysis of the membrane formation process, considering the dope solution composition, evaporation step, and structural properties of polyimides, was conducted. The effect of the choice of polymer/solvent/co-solvent/non-solvent was found to be very profound and qualitatively predictable through introduction of a complex solubility parameter. Increasing value of complex solubility parameter can predict higher rejections. The study of the evaporation in PI OSN membrane formation has shown that this optional step is undesirable, as its presence results in unaltered rejection and significantly lower flux. Nevertheless, the presence of a co-solvent, regardless of whether it is volatile or not, was found to be required as it promotes formation of a dense membrane top layer. We have also studied sensitivity of PI OSN membranes to small perturbations in polymer characteristics, such as: molecular weight, alternating diisocyanates to form the PI chain, and copolymerisation method (block vs random). Finally, we proposed a less hazardous route for the PI OSN membrane formation process, which would reduce environmental impact without compromising the separation performance of the existing membranes.EThOS - Electronic Theses Online Service6th Framework Programme of the European Commission Marie Curie InitiativeGBUnited Kingdo

Spatial and temporal structure of fish assemblages in an "inverse estuary", the Sine Saloum system (Senegal)

As a consequence of the Sahelian drought, the Sine Saloum, a large estuarine system located in Senegal (West Africa), has become an "inverse estuary" since the late sixties, i.e. salinity increases upstream and reaches 100 in some places. To study the fish assemblages of such a modified system, a survey was conducted in 1992, collecting fish every two months with a purse seine at eight sites spread over the three main branches of the estuary. A total of 73 species belonging to 35 families were identified. Eight species comprised 97% of the total numbers of fish. The predominant species was a small clupeid, Sardinella maderensis, representing more than half of the total biomass and nearly 70% of the total number of fish. The spatio-temporal structure of the fish assemblages was studied using the STATIS-CoA method, which combines the multitable approach with the correspondence analysis method. Whatever the season, a strong spatial organization of fish assemblages was observed, mainly related to depth and salinity. Three types of assemblages were identified. In shallow water areas, fish assemblages were dominated by Mugilidae, Gerreidae and Cichlidae and were stable with time. In open water areas, large fluctuations in the species composition were observed, due to the occasional presence of large schools of pelagic species: in the southern area, where salinity and water transparency were the lowest, the main species were Ilisha africana, Brachydeuterus auritus and Chloroscombrus chrysurus, associated with a few Sciaenidae and Tetraodontidae, while the poorest areas were characterized by only two dominant species, S. maderensis and Scomberomorus tritor