Center National Des Science Halieutiques Of Boussoura Cnshb

Conakry, Guinea

Center National Des Science Halieutiques Of Boussoura Cnshb

Conakry, Guinea
Time filter
Source Type

Shin Y.-J.,Institute Of Recherche Pour Le Developpement | Shannon L.J.,University of Cape Town | Bundy A.,Bedford Institute of Oceanography | Coll M.,CSIC - Institute of Marine Sciences | And 24 more authors.
ICES Journal of Marine Science | Year: 2010

Background is provided to the selection of ecological indicators by the IndiSeas Working Group, and the methodology adopted for analysis and comparison of indicators across exploited marine ecosystems is documented. The selected indicators are presented, how they are calculated is explained, and the philosophy behind the comparative approach is given. The combination of selected indicators is intended to reflect different dynamics, tracking processes that display differential responses to fishing, and is meant to provide a complementary means of assessing marine ecosystem trends and states. IndiSeas relied on inputs and insights provided by the local experts from participating ecosystems, helping to understand state and trend indicators and to disentangle the effect of other potential ecosystem drivers, such as climate variability. This project showed that the use of simple and available indicators under an ecosystem approach can achieve a real, wide-reaching evaluation of marine ecosystem status caused by fishing. This is important because the socio-economics of areas where fishing activities develop differs significantly around the globe, and in many countries, insufficient data are available for complex and exhaustive analyses. © 2010 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

Jouffre D.,Montpellier University | Borges M.D.F.,Institute Investigacao das Pescas e Do Mar IPIMAR INRB | Bundy A.,Bedford Institute of Oceanography | Coll M.,CSIC - Institute of Marine Sciences | And 7 more authors.
ICES Journal of Marine Science | Year: 2010

Under the context of an ecosystem approach to fisheries (EAF), there is keen interest in providing insights into the evolution of exploited ecosystems using simple ecosystem indicators. Many nations have long-term scientific research surveys, originally driven by conventional approaches in fisheries assessment and management. The aim of this study is to address the practical concerns linked to current objectives of monitoring simple EAF indicators, using data from surveys that were not historically designed for the purpose. Based on the results of an expert survey designed to collect expert knowledge on research surveys from scientists working on different ecosystems worldwide, a list of challenges faced during indicator estimation is highlighted, along with associated concerns and constraints. The work provides additional information useful in the interpretation of the results obtained on the state and trends of ecosystems using EAF indicators by the IndiSeas WG. Further, the related discussion provides potential pathways that could be useful for future research and development aiming to improve the ecosystem indicator approach in the operational context of EAF. The question of the utility for EAF of using historical dataseries of scientific trawl series is also discussed. Such long-term series are concluded to be useful, that they are even inescapable (since the past cannot be resamplied), and that EAF therefore brings a supplementary reason for continuing such monitoring and to incorporate new insights in how research surveys may be conducted. © 2009 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

Coll M.,Institute Of Recherche Pour Le Developpement | Coll M.,CSIC - Institute of Marine Sciences | Shannon L.J.,University of Cape Town | Kleisner K.M.,National Oceanic and Atmospheric Administration | And 40 more authors.
Ecological Indicators | Year: 2016

IndiSeas ("Indicators for the Seas") is a collaborative international working group that was established in 2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem using several criteria (i.e., ecological meaning, sensitivity to fishing, data availability, management objectives and public awareness). The suite comprised: (i) the inverse coefficient of variation of total biomass of surveyed species, (ii) mean fish length in the surveyed community, (iii) mean maximum life span of surveyed fish species, (iv) proportion of predatory fish in the surveyed community, (v) proportion of under and moderately exploited stocks, (vi) total biomass of surveyed species, and (vii) mean trophic level of the landed catch. In line with the Nagoya Strategic Plan of the Convention on Biological Diversity (2011-2020), we extended this suite to emphasize the broader biodiversity and conservation risks in exploited marine ecosystems. We selected a subset of indicators from a list of empirically based candidate biodiversity indicators initially established based on ecological significance to complement the original IndiSeas indicators. The additional selected indicators were: (viii) mean intrinsic vulnerability index of the fish landed catch, (ix) proportion of non-declining exploited species in the surveyed community, (x) catch-based marine trophic index, and (xi) mean trophic level of the surveyed community. Despite the lack of data in some ecosystems, we also selected (xii) mean trophic level of the modelled community, and (xiii) proportion of discards in the fishery as extra indicators. These additional indicators were examined, along with the initial set of IndiSeas ecological indicators, to evaluate whether adding new biodiversity indicators provided useful additional information to refine our understanding of the status evaluation of 29 exploited marine ecosystems. We used state and trend analyses, and we performed correlation, redundancy and multivariate tests. Existing developments in ecosystem-based fisheries management have largely focused on exploited species. Our study, using mostly fisheries independent survey-based indicators, highlights that biodiversity and conservation-based indicators are complementary to ecological indicators of fishing pressure. Thus, they should be used to provide additional information to evaluate the overall impact of fishing on exploited marine ecosystems. © 2015 Elsevier Ltd. All rights reserved.

Trouillet B.,University of Nantes | Guineberteau T.,University of Nantes | Bernardon M.,British Petroleum | Le Roux S.,Center National Des Science Halieutiques Of Boussoura Cnshb
Marine Policy | Year: 2011

Maritime governance stakes are important in West Africa, if only due to the dominant role of fisheries, which coastal populations mainly depend on. In this context, with reference to the fishery sector mostly studied in two countries (Guinea and Mauritania), this paper aims to identify and synthesize the challenges to be met towards developing the governance of marine spaces. To this end, the analysis is based on field knowledge, which provides input into a grid set according to the various integration levels of the concept of ICZM. This paper thus reports the major methodological obstacles to be overcome, commensurate to the stakes insofar as marine policies can and must contribute to the economic and social development of this region. © 2010 Elsevier Ltd.

Le Fur J.,Montpellier SupAgro | Guilavogui A.,Center National Des Science Halieutiques Of Boussoura Cnshb | Teitelbaum A.,British Petroleum
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2011

We assessed the quality of fishermen's local ecological knowledge, or LEK, as a potential source of information about coastal ecosystem functioning in the Republic of Guinea. Interviews were conducted by means of partial immersion or repeated surveys at six landing sites. In each site and for each topic, discussions were conducted with 3 to 15 individual fishermen and 1 to 10 groups of fishermen. Knowledge was obtained about habitats, substrate preferences, the location of nurseries, reproductive cycles, fish diet, and the trophic network of the Sciaenid community, the major resource for fisheries in this area. We systematically compared the reliability of the information collected with that of scientific information collected in parallel surveys or published data. The contribution of LEK should be considered on a case-by-case basis. Indeed, LEK could be used as (i) a supplementary source of scientific studies (seabed description), (ii) a basis for new scientific investigation (species reproductive cycle), (iii) the only possibility to obtain information (nursery location), (iv) a surrogate to scientific surveys providing an identical level of validity (fish diets) or a satisfactory proxy (trophic network) in a context of limited resources and data in which wide-ranging knowledge relating to the entire coast must be obtained.

Kleisner K.M.,National Oceanic and Atmospheric Administration | Coll M.,Institute Of Recherche Pour Le Developpement | Lynam C.P.,CEFAS - Center for Environment, Fisheries and Aquaculture Science | Bundy A.,Bedford Institute of Oceanography | And 23 more authors.
Ecosystem Services | Year: 2015

Fisheries provide critical provisioning services, especially given increasing human population. Understanding where marine communities are declining provides an indication of ecosystems of concern and highlights potential conflicts between seafood provisioning from wild fisheries and other ecosystem services. Here we use the nonparametric statistic, Kendall's tau, to assess trends in biomass of exploited marine species across a range of ecosystems. The proportion of 'Non-Declining Exploited Species' (NDES) is compared among ecosystems and to three community-level indicators that provide a gauge of the ability of a marine ecosystem to function both in provisioning and as a regulating service: survey-based mean trophic level, proportion of predatory fish, and mean life span. In some ecosystems, NDES corresponds to states and temporal trajectories of the community indicators, indicating deteriorating conditions in both the exploited community and in the overall community. However differences illustrate the necessity of using multiple ecological indicators to reflect the state of the ecosystem. For each ecosystem, we discuss patterns in NDES with respect to the community-level indicators and present results in the context of ecosystem-specific drivers. We conclude that using NDES requires context-specific supporting information in order to provide guidance within a management framework. © 2015 Elsevier B.V.

Camara M.,Center National Des Science Halieutiques Of Boussoura Cnshb | Merigot B.,Montpellier University | Leprieur F.,Montpellier University | Tomasini J.,Montpellier University | And 4 more authors.
African Journal of Marine Science | Year: 2016

In a context of growing fishing pressures and recommendations for an ecosystem approach to fisheries, there is a need to monitor changes in fish communities over time. In this study, we analysed data from scientific trawl surveys carried out on the continental shelf off Guinea between 1985 and 2012. We performed factorial analyses and calculated biodiversity indices to characterise the changes in the structure and composition of fish communities that occurred over the 28-year period in this area, particularly given intensive fishing activities. We show that, over the study period, fish communities on the Guinean shelf were structured primarily according to spatial factors, with temporal changes being less pronounced than expected. However, a temporal analysis of biodiversity indices and species dominance showed that the intensification of fishing had significant effects on the general ecological features of the fish assemblages under study. There was a decrease in fish density and in mean trophic level. In addition, there were changes in species dominance, whereby large, slow-growing species with high commercial value were gradually replaced by smaller, fast-growing species of lesser commercial interest. These results from field observations are in line with some conclusions from previous modelling studies in the same geographical area, and provide further support for the hypothesis of a progressive ‘ecosystem effect of fishing’ occurring in Guinean waters. © 2016 NISC (Pty) Ltd

Van Waerebeek K.,COREWAM Senegal | Van Waerebeek K.,Peruvian Center for Cetacean Research | Djiba A.,COREWAM Senegal | Djiba A.,Cheikh Anta Diop University | And 3 more authors.
African Zoology | Year: 2013

Seventeen confirmed and four probable sightings of humpback whales, Megaptera novaeangliae, were documented from platform-of-opportunity Research Vessel (R/V) Dr. Fridtjof Nansen in a passing-mode visual survey of continental shelf waters between Conakry and Cap Vert Peninsula (Dakar), 21 October -5 November 2011. None were encountered in the northern stratum Dakar-Agadir, 6 November -15 December 2011. Total visual survey effort was 468 h, 01 min, covering 5335 km. Depending on the exclusion or inclusion of probable records, the sum of group sizes totalled 33 or 43 individuals, respectively. Humpback whale encounter rates between Conakry and Dakar then amounted to 1.74 or 2.27 whales/ 100 km, respectively. Group sizes ranged from 1-6 individuals (mean = 1.94, S.D. = 1.20, n = 17; median = 2). Minimally five of 17 groups (29.4%) consisted of adult-calf pairs, with a minimum crude birth rate ranging from 0.060-0.152. All sightings occurred in shallow water, 22-60 m (mean = 35.0 m, S.D. = 10.13, n = 17) but survey effort in deeper, offshore water was negligible. Sea-surface temperature at sighting locations ranged from 25.5-29.0°C (mean = 27.34, S.D. = 0.96, n = 17). No humpback whales were sighted during a second survey covering Conakry-Tangier-Las Palmas, from 9 May to 22 July 2012 (519 h, 13 min; 6278 km). The Cape Verde Islands comprised, to date, the only known wintering ground located in the North-East Atlantic. This study showed that Senegal, The Gambia, Guinea-Bissau and Guinea are normal range states for M. novaeangliae. A temporal signature, six to seven months out-of-phase with mid-season in the Cape Verde Islands, and neonate presence strongly suggest that the wide Conakry-Dakar continental shelf serves as both wintering and nursery grounds for a South Atlantic stock, in agreement with Bamy et al. (2010). This stock may comprise the northwesternmost component of the large humpback whale assemblage migrating in and out of the northern Gulf of Guinea in austral winter/spring. Further research is required to consolidate insights linking temporal and spatial distribution off western Africa with hemispheric stock identity and migration paths.

Loading Center National Des Science Halieutiques Of Boussoura Cnshb collaborators
Loading Center National Des Science Halieutiques Of Boussoura Cnshb collaborators