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The structure of demersal assemblages off Namibia in relation to abiotic factors
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: H. Hamukuaya G. Bianchi D. BairdGroundfish surveys carried out between October 1992 and October 1996 were used to describe the demersal assemblages of the northern Benguela along the Namibian coast. Multivariate analyses indicated a clear separation between shelf and slope habitats, which were divided into... -
Fish sampling in the marine-dominated Kariega Estuary, South Africa, using a demersal otter trawl: day/night effects
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: SE Bailey --- , South Africa NC James --- , South AfricaVery few demersal fish assemblage studies using otter trawls in estuaries have been done in South Africa and none of these have tested for the effects of diel period. This study aimed to test whether diel period affects otter trawl... -
How can science contribute to an ecosystem approach to pelagic, demersal and rock lobster fisheries in South Africa?
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: LJ Shannon PM Cury D Nel CD Van Der Lingen RW Leslie SL Brouwer AC Cockcroft L HutchingsSouth Africa is committed to moving towards an Ecosystem Approach to Fisheries (EAF) and has laid the foundations for this using a three-pronged approach: through a project (EAF Feasibility Study) under the Benguela Current Large Marine Ecosystem Programme; through a... -
Decline of demersal resources in North-West Africa: an analysis of Mauritanian trawl-survey data over the past 25 years
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: D Gascuel P Labrosse B Meissa MO Taleb Sidi S GuénetteMauritania is characterised by fast-growing fisheries that have developed over the past decades. Since 1982, scientific trawl surveys have been conducted regularly, allowing assessment of the impact of this increasing fishing pressure on exploited species as well as on demersal... -
Seabird bycatch in the demersal longline fishery off southern Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SL Petersen --- , South Africa MB Honig --- , South Africa PG Ryan --- DST/NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, South Africa LG Underhill --- Animal Demography Unit, Department of Zoology, South Africa M Goren --- , South AfricaThis study assesses seabird bycatch in the demersal longline hake (Merluccius capensis and M. paradoxus) fishery in the southern Benguela region. Observers collected seabird bycatch data from 2 412 sets (14 million hooks) in the South African fishery, accounting for... -
Assessing the suitability of commercial fisheries data for local-scale marine spatial planning in South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Chalmers --- Department of Ichthyology and Fisheries Science, South Africa A Oosthuizen --- Park Planning and Development, South African National Parks, South Africa A Götz --- Department of Ichthyology and Fisheries Science, South Africa A Paterson --- South African Institute for Aquatic Biodiversity, South Africa WHH Sauer --- Department of Ichthyology and Fisheries Science, South AfricaThis study integrates fisheries logbook data with observer and vessel monitoring system (VMS) data in order to assess the accuracy of reported data and to develop high-resolution spatial data suitable for use in local-scale marine spatial planning analyses. Spatial assessments... -
The influence of selected environmental parameters on the distribution of the dominant demersal fishes in the Kariega Estuary channel, South Africa
Item type: Journal Article • Journal: African Zoology • Authors: Naomi Richardson --- Department of Ichthyology and Fisheries Science, South Africa Alan K. Whitfield --- South African Institute for Aquatic Biodiversity, South Africa Angus W. Paterson --- South African Institute for Aquatic Biodiversity, South AfricaThe Kariega Estuary channel was sampled using an otter trawl and the demersal fish catch analysed using the PRIMER statistical package. A biological-environmental (BIOENV) analysis was undertaken using the catch per unit effort ichthyofaunal data from the spring/summer period of... -
Rapid fish stock depletion in previously unexploited seamounts: the case of
Beryx splendens from the Sierra Leone Rise (Gulf of Guinea)Item type: Journal Article • Journal: African Journal of Marine Science • Authors: F Salmerón --- Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Málaga, Spain JC Báez --- Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Málaga, Spain D Macías --- Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Málaga, Spain L Fernandez-Peralta --- Instituto Español de Oceanografía (IEO), Centro Oceanográfico de Málaga, Spain A Ramos --- IEO, Centro Oceanográfico de Vigo, Subida a Radio Faro, Vigo (Pontevedra), SpainFish stocks associated with seamounts may be particularly susceptible to overexploitation. From January to July 2001, the Spanish Oceanographic Institute (IEO) conducted an experimental fishing survey entitled ‘Palguinea-2001’ on the seamounts of the Sierra Leone Rise. Beryx splendens (commonly called... -
Anchoring to determine negotiated catch limits: a case study of an industrial fishery in Oman
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HS Al-Masroori --- Department of Marine Science and Fisheries, Sultanate of Oman S Bose --- Department of Natural Resource Economics, Sultanate of OmanDespite refinement in scientific methods of setting total allowable catches (TACs), the choice of values is affected by uncertainty that arises as a result of incomplete information and the behavioural intentions of resource users, among others. In this context, this... -
A brief overview of the ACEP project: Ecosystem Processes in the KwaZulu-Natal Bight
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: ST Fennessy --- Oceanographic Research Institute, South Africa MJ Roberts --- Branch: Oceans and Coasts, South Africa AW Paterson --- South African Institute for Aquatic Biodiversity, South AfricaThis introductory paper lays the basis for this supplementary issue by briefly presenting the state of knowledge on the KwaZulu-Natal (KZN) Bight at the start of this multi-disciplinary, multi-institutional, ship-based research project that ran from 2009 to 2013. The rationale... -
Riverine dominance of a nearshore marine demersal food web: evidence from stable isotope and C/N ratio analysis
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AM de Lecea --- School of Life Sciences, University of KwaZulu-Natal, South Africa AJ Smit --- School of Life Sciences, University of KwaZulu-Natal, South Africa ST Fennessy --- Oceanographic Research Institute, South AfricaThe Thukela Bank, KwaZulu-Natal, supports a diverse ecosystem and South Africa’s only prawn fishery. Oceanographic studies suggest riverine input is not important for the biology of this system, whereas biological studies suggest the contrary, with prawn catches increasing with increased... -
Geostatistical modelling of the spatial life history of post-larval deepwater hake Merluccius paradoxus in the Benguela Current Large Marine Ecosystem
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: T Jansen --- Benguela Current Commission, Namibia K Kristensen --- Technical University of Denmark – National Institute of Aquatic Resources (DTU Aqua), Denmark TP Fairweather --- Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries (DAFF), South Africa P Kainge --- Ministry of Fisheries and Marine Resources (MFMR), Namibia JN Kathena --- Ministry of Fisheries and Marine Resources (MFMR), Namibia MD Durholtz --- Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries (DAFF), South Africa JE Beyer --- Technical University of Denmark – National Institute of Aquatic Resources (DTU Aqua), Denmark UH Thygesen --- Technical University of Denmark – National Institute of Aquatic Resources (DTU Aqua), DenmarkOptimal and sustainable management of fish resources cannot be ensured without a thorough understanding of the migration patterns and population (demographic stock) structure. Recent studies suggest that these aspects of the economically and ecologically important deepwater hake Merluccius paradoxus are... -
The impact of river flooding and high flow on the demersal fish assemblages of the freshwater-dominated Great Fish Estuary, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: P Nodo --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa NC James --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa A-R Childs --- Department of Ichthyology and Fisheries Science, South Africa MDV Nakin --- Department of Biological and Environmental Sciences, South AfricaFreshwater inflow has a strong impact on the biological, chemical and physical characteristics of estuaries, which in turn affect the distribution and abundance of estuarine organisms. Increased climatic variability associated with climate change is predicated to modify precipitation patterns, which... -
Spatial and ontogenetic variability in the diet and trophic ecology of two co-occurring catsharks (Scyliorhinidae) off South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GM van der Heever --- , South Africa CD van der Lingen --- , South Africa RW Leslie --- , South Africa MJ Gibbons --- , South AfricaThe Izak catshark Holohalaelurus regani and the yellow-spotted catshark Scyliorhinus capensis both occur over the continental shelf around South Africa and are often caught together as bycatch in demersal trawls. Yet our understanding of their diet is fragmented, which makes... -
Spatial environmental variability shapes the diversity of bottom ecosystems on the western Gulf of Guinea shelf
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: C Denechaud --- Institute of Marine Research (IMR), Norway E Dovlo --- Fisheries Scientific Survey Division (FSSD), Ghana T Joanny --- Centre de Recherches Océanologiques (CRO), Côte d’Ivoire VS Osei --- Fisheries Scientific Survey Division (FSSD), Ghana L Buhl-Mortensen --- Institute of Marine Research (IMR), Norway A Staby --- Institute of Marine Research (IMR), NorwayThe western Gulf of Guinea is characterised by seasonal upwellings and hosts a large diversity of marine species. Although the assemblages of bottom fishes and benthic organisms are periodically assessed, there has been little research investigating these in tandem. We...