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Development of acoustic techniques for assessment of orange roughy Hoplostethus atlanticus biomass off Namibia, and of methods for correcting for bias
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: D. C. Boyer I. HamptonOrange roughy form dense spawning aggregations in specific small areas in deep water on the Namibian shelf between late June and early August each year. The biomass in three such areas, where most commercial fishing occurs (the Johnies, Frankies and... -
Towards a catchability constant for trawl surveys of Namibian hake
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: I. Huse T. Iilende T. StrømmeA trawl catches only a portion of the fish in its path. The term catchability therefore refers to the fraction of the available fish caught. A method was developed and tested to establish catchability constants for trawl surveys of Namibian... -
Comparison of horse mackerel length frequencies obtained from research vessels and commercial midwater trawlers: implications for biomass estimation
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: G. Bauleth-D'Almeida J-O. Krakstad A. KanandjemboThe validity of abundance estimates from hydroacoustic surveys relies, inter alia, on the ability of the fishing gear on the research vessel to sample non-selectively. This study compares the length frequencies of Cape horse mackerel Trachurus trachurus capensis taken in... -
Variable spatial structure of schooling pelagic fish off Namibia: implications for acoustic surveys
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: J. C. Coetzee O. A. Misund G. OechslinSchools of horse mackerel Trachurus trachurus capensis, sardine Sardinops sagax and round herring Etrumeus whiteheadi were surveyed by conventional echo-integration along systematic transects. The transects were surveyed twice, in opposite directions. Clupeoid biomass was concentrated in a few dense aggregations,... -
Dynamics of the pelagic component of Namibian hake stocks
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: T. Iilende T. Strømme E. JohnsenA study was undertaken to investigate the spatial, diurnal and interannual dynamics of the pelagic component of Namibian hake stocks. Data were derived from trawl surveys conducted on board the R.V. Dr Fridtjof Nansen during the period 1991–1999. In addition... -
Direct hydroacoustic observations of chokka squid Loligo vulgaris reynaudii spawning activity in deep water
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: M. J. Roberts M. Barange M. R. Lipiński M. R. ProwseUnusual and distinct hydroacoustic targets were observed in November 1996, May 1998 and November 1998 during routine pelagic biomass surveys off the south coast of South Africa. During the November 1996 survey, seven such targets were observed near the bottom... -
The low-frequency vocal repertoire of adult African dwarf crocodiles
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Agata Staniewicz --- University of Bristol, United Kingdom Gráinne McCabe --- United Kingdom, Marc Holderied --- University of Bristol, United KingdomAcoustic techniques are rapidly becoming powerful tools for species monitoring and biodiversity assessment. These methods can be particularly appropriate for forest-dwelling crocodiles which are difficult to survey visually. However, basic vocal-repertoire data is lacking for many of the poorly known... -
Distribution of Nile perch Lates niloticus in southern Lake Victoria is determined by depth and dissolved oxygen concentrations
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: PC Goudswaard --- , the Netherlands EFB Katunzi --- , Tanzania JH Wanink --- , the Netherlands F Witte --- , the NetherlandsAlthough Nile perch Lates niloticus is assumed to be sensitive to low oxygen concentrations, it was found in deep water in Lake Victoria, where oxygen depletion is common during the rainy season. Since factors determining Nile perch distribution are not... -
Evaluation of acoustic transmitter implantation and determination of post-translocation behaviour of largemouth bass Micropterus salmoides in a South African impoundment
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: CF Huchzermeyer --- Department of Ichthyology and Fisheries Science (DIFS), South Africa OLF Weyl --- , South Africa PD Cowley --- , South AfricaLargemouth bass Micropterus salmoides are an important angling species that are often displaced during catch-and-release fishing tournaments. The impact of acoustic transmitter implantation on this species and the effect of displacement distance on their behaviour were tested. In April 2010,... -
In Situ Measurements of the Acoustic Target Strength of Cape Horse Mackerel Trachurus Trachurus Capensis Off Namibia
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: B. E. Axelsen G. Bauleth-D'Almeida A. KanandjemboThe acoustic target strength (TS) of Cape horse mackerel Trachurus trachurus capensis was measured in situ at 38 kHz during two surveys over the Namibian continental shelf in 1998 and 1999 using a SIMRAD EK500 echosounder/ES38D submersible split-beam transducer. Scattered... -
Distribution patterns of key fish species of the southern Benguela ecosystem: an approach combining fishery-dependent and fishery-independent data
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L. Pecquerie L. Drapeau P. Fréon J. C. Coetzee R. W. Leslie M. H. GriffithsWithin the context of an ecosystem approach for fisheries, there is a need for quantitative information on distributions of key marine species. This information is valuable input for modelling species interactions in the southern Benguela ecosystem. In the present study,... -
Interpreting behavioural data from Radio-Acoustic Positioning Telemetry (RAPT) systems
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: PR Rigby Y Andrade RK O'DorTo detect behavioural patterns of individually tagged squid Loligo vulgaris reynaudii in a Radio-Acoustic Positioning Telemetry (RAPT) buoy array, trajectories reflecting the four dimensions of latitude, longitude, depth and time were plotted from data collected during field experiments in South... -
The potential for using acoustic tracking to monitor the movement of the West Coast rock lobster Jasus lalandii
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: LJ Atkinson S Mayfield AC CockcroftAlthough acoustic tracking has been used to study the movement of several species of clawed and spiny lobsters, only recent technological advances have provided sufficiently small transmitters to examine the utility of using acoustic tracking as a means to analyse... -
Vertical migration, catchability and acoustic assessment of semi-pelagic Cape horse mackerel Trachurus trachurus capensis in the southern Benguela
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: M Barange SC Pillar I Huse L HutchingsThe vertical distribution and migration of the Cape horse mackerel Trachurus trachurus capensis were investigated on the basis of midwater and bottom trawl collections taken over diel cycles at two sites on South Africa's south coast. Attempts were also made... -
Identification of acoustic targets off Angola using General Discriminant Analysis
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: F Vaz Velho BE Axelsen P Barros G Bauleth-D'AlmeidaPelagic fish off Angola constitute about 80% of the total fish landed and some 75% of the animal protein in the diet of the coastal population. The primary means of estimating stock abundance is through acoustic surveys, a method that... -
The 2005 KwaZulu-Natal sardine run survey sheds new light on the ecology of small pelagic fish off the east coast of South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JC Coetzee --- Branch Fisheries, Department of Agriculture, South Africa D Merkle --- Branch Fisheries, Department of Agriculture, South Africa L Hutchings --- Oceans and Coasts, Department of Environmental Affairs, South Africa CD van der Lingen --- Branch Fisheries, Department of Agriculture, South Africa M van den Berg --- Oceans and Coasts, Department of Environmental Affairs, South Africa MD Durholtz --- Branch Fisheries, Department of Agriculture, South AfricaDespite much public awareness surrounding the annual migration of sardine Sardinops sagax northward along the east coast of South Africa in winter each year, relatively little research effort has been expended to improve understanding of the ‘sardine run’. For this... -
Acoustic behaviour of southern right whales in relation to numbers of whales present in Walker Bay, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: LH Hofmeyr-Juritz --- , South Africa PB BestEstimating numbers of whales present in an area from recorded call rates could be a useful conservation tool. We recorded southern right whale Eubalaena australis vocalisations and presence in Walker Bay on the south coast of South Africa. In all,... -
Quantifying the degree of protection afforded by a no-take marine reserve on an exploited shark
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: C da Silva --- Fisheries Research, Department of Agriculture, South Africa SE Kerwath --- Fisheries Research, Department of Agriculture, South Africa CG Attwood --- Marine Research Institute, Zoology Department, South Africa EB Thorstad --- , Norway PD Cowley --- , South Africa F Økland --- , Norway CG Wilke --- Fisheries Research, Department of Agriculture, South Africa TF Næsje --- , NorwaySharks have been shown to benefit from the protection of marine protected areas (MPAs). There is, however, little information on the degree of protection by MPAs to shark populations. The movements of individual smoothhound sharks Mustelus mustelus in, and adjacent... -
Corewood in South African pine: necessity and opportunities for improvement
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: FS Malan --- , South AfricaSouth Africa has made excellent progress in breeding plantation trees fulfilling the primary demands of improved volume growth, stem and branching characteristics, tolerance to pests and diseases, and general adaptability. This has had marked positive impacts on wood quality, as... -
The flexural properties of young Pinus elliottii x Pinus caribaea var. hondurensis timber from the Southern Cape and their prediction from acoustic measurements
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: CB Wessels --- Department of Forest and Wood Science, South Africa GP Dowse --- Department of Forest and Wood Science, South Africa HC Smit --- Department of Forest and Wood Science, South AfricaThe objectives of this study were to determine the bending strength and stiffness properties of young Pinus elliottii x P. caribaea var. hondurensis timber from the Southern Cape, South Africa, and to evaluate the predictability of these properties from acoustic... -
First tracking of white stumpnose Rhabdosargus globiceps (Sparidae) in a South African marine protected area
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CG Attwood PD Cowley SE Kerwath TF Naesje F Økland EB ThorstadThere is a growing recreational fishery for white stumpnose Rhabdosargus globiceps (Sparidae) in Langebaan Lagoon, part of South Africa's West Coast National Park. The upper reaches of the lagoon are protected from fishing, but the extent to which the closure... -
A visual and acoustic survey for harbour porpoises off North-West Africa: further evidence of a discrete population
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: O Boisseau J Matthews D Gillespie C Lacey A Moscrop N El OuamariThe distribution of harbour porpoises Phocoena phocoena in southern Europe and along the Atlantic African coast is poorly understood, with tentative assessments suggesting a discrete West African population with a northern limit around the Straits of Gibraltar. This study describes... -
Refined estimates of South African pelagic fish biomass from hydro-acoustic surveys: quantifying the effects of target strength, signal attenuation and receiver saturation
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JC Coetzee D Merkle CL de Moor NM Twatwa M Barange DS ButterworthThe biomass of small pelagic fish species off the coast of South Africa has been monitored since 1984 using hydro-acoustic survey techniques. These time-series of spawner biomass and recruitment estimates form the basis for management of both the South African... -
Revised estimates of abundance of South African sardine and anchovy from acoustic surveys adjusting for echosounder saturation in earlier surveys and attenuation effects for sardine
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CL de Moor DS Butterworth JC CoetzeeHydro-acoustic surveys have been used to provide annual estimates of May recruitment and November spawner biomass of the South African sardine Sardinops sagax and anchovy Engraulis encrasicolus resources since 1984. These time-series of abundance estimates form the backbone of the... -
Estuarine habitat use by juvenile dusky kob Argyrosomus japonicus (Sciaenidae), with implications for management
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: PD Cowley SE Kerwath A-R Childs EB Thorstad F Økland TF NæsjeThe spatial and temporal area-use patterns of estuarine-dependent juvenile dusky kob Argyrosomus japonicus in the Great Fish Estuary, South Africa, were examined using acoustic telemetry. In all, 29 individuals (307–400 mm total length) were surgically equipped with individually coded transmitters... -
Catching and tracking the world's largest Zambezi (bull) shark Carcharhinus leucas in the Breede Estuary, South Africa: the first 43 hours
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: ME McCord SJ LamberthThe Zambezi or bull shark Carcharhinus leucas is a large, predatory shark that occurs in warm-temperate, tropical and subtropical coastal and estuarine systems worldwide. To confirm reports of Zambezi sharks in the Breede Estuary on the south-west coast of South... -
Design and calibration of an acoustic telemetry system subject to upwelling events
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Singh --- Department of Environmental Affairs, South Africa NJ Downey --- , South Africa MJ Roberts --- Department of Environmental Affairs, South Africa DM Webber --- , Canada MJ Smale --- , South Africa MA van den Berg --- Department of Environmental Affairs, South Africa RT Harding --- Department of Environmental Affairs, South Africa DC Engelbrecht --- , South Africa BM Blows --- , South AfricaThe experiments described were designed to calibrate a hexagonal array of VEMCO VR2 receivers and transmitters (model V9P-6L-S256) in isothermal and stratified water columns off the south coast of South Africa. The array, configured with 500 m between receivers, was... -
A preliminary study of the effects of aircraft noise on families who reside in close proximity to an airport
Item type: Journal Article • Journal: South African Family Practice • Authors: D Pillay --- University of the Witwatersrand, K Archary --- University of the Witwatersrand, S Panday --- University of KwaZulu-Natal,Background: The use of air transportation has grown in the last century, escalating the noise exposure of families residing in close proximity to airports. The audiological effects need to be assessed to determine the impact of this increase on children... -
New discoveries on the ecology and echolocation of the heart-nosed bat Cardioderma cor with a contribution to the phylogeny of Megadermatidae
Item type: Journal Article • Journal: African Zoology • Authors: Peter Kaňuch --- Institute of Forest Ecology, Slovak Academy of Sciences, Slovakia Tatiana Aghová --- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Czech Republic Yonas Meheretu --- Department of Biology, Mekelle University, Ethiopia Radim Šumbera --- Department of Zoology, University of South Bohemia, Czech Republic Josef Bryja --- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Czech RepublicIn this study we report findings in roosting ecology, ectoparasites, echolocation characteristics and the phylogenetic position of Cardioderma cor, an impressive bat species that is distributed throughout the savannas and woodlands of eastern Africa. For individuals caught in Mago National... -
Comparative analysis of long-range calls in equid stallions (Equidae): are acoustic parameters related to social organization?
Item type: Journal Article • Journal: African Zoology • Authors: Richard Policht --- Institute of Tropics and Subtropics, Czech University of Life Sciences Prague, Czech Republic Alexis Karadžos --- Department of Zoology, Faculty of Science, Czech Republic Daniel Frynta --- Department of Zoology, Faculty of Science, Czech RepublicEvolution of long-distance communication in equids may correspond with species-specific types of social organization. To compare harem-forming species (type I) with those that do not establish permanent social units (type II), we conducted a comparative analysis of stallion long-range calls... -
First assessment of estuarine space use and home range of juvenile white steenbras, Lithognathus lithognathus
Item type: Journal Article • Journal: African Zoology • Authors: R. H. Bennett --- Department of Ichthyology and Fisheries Science, South Africa A. R. Childs --- Department of Ichthyology and Fisheries Science, South Africa P. D. Cowley --- South African Institute for Aquatic Biodiversity, South Africa T. F. Næsje --- Norwegian Institute for Nature Research, Norway E. B. Thorstad --- Norwegian Institute for Nature Research, Norway F. Økland --- Norwegian Institute for Nature Research, NorwayThe spatial dynamics and home range sizes of early juvenile white steenbras (Lithognathus lithognathus Cuvier, 1829) in the permanently open Great Fish Estuary, South Africa, were assessed using acoustic telemetry. Seven individuals (154–184 mm fork length) tagged with acoustic transmitters... -
Seasonality, behaviour and philopatry of spotted ragged‑tooth sharks Carcharias taurus in Eastern Cape nursery areas, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MJ Smale --- Port Elizabeth Museum at Bayworld, South Africa ML Dicken --- Port Elizabeth Museum at Bayworld, South Africa AJ Booth --- Department of Ichthyology and Fisheries Science, South AfricaSpotted ragged‑tooth sharks Carcharias taurus occur along the southern and eastern coasts of South Africa. We report on movements of juveniles and adults within a known nursery area on the Eastern Cape coast using acoustic telemetry. The focus area of... -
Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: A Blaison --- IRD La Réunion, UMR MARBEC (IRD/IFREMER/UM/CNRS), France S Jaquemet --- Université de La Réunion, France D Guyomard --- Comité Régional des Pêches Maritimes et des Elevages Marins de La Réunion (CRPMEM), France G Vangrevelynghe --- Squal'Idées, Stella, France T Gazzo --- WEST, Saint Gilles, France G Cliff --- KwaZulu-Natal Sharks Board, South Africa P Cotel --- IRD La Réunion, UMR MARBEC (IRD/IFREMER/UM/CNRS), France M Soria --- IRD La Réunion, UMR MARBEC (IRD/IFREMER/UM/CNRS), FranceA fisheries‑independent survey using longlines and drumlines, and an acoustic telemetry study, revealed that bull sharks Carcharhinus leucas and tiger sharks Galeocerdo cuvier occur throughout the year off the west coast of Reunion Island. The research, which commenced in 2011,... -
Movement behaviour of largemouth bass Micropterus salmoides in a South African impoundment
Item type: Journal Article • Journal: African Zoology • Authors: Dylan H Howell --- Department of Ichthyology and Fisheries Science, South Africa Paul D Cowley --- Department of Ichthyology and Fisheries Science, South Africa Amber-Robyn Childs --- Department of Ichthyology and Fisheries Science, South Africa Olaf LF Weyl --- Department of Ichthyology and Fisheries Science, South AfricaThe objectives of this study were to describe movements and area use patterns of largemouth bass Micropterus salmoides in relation to abiotic factors (water temperature, river inflow and water level). The study was conducted in the Kubusi arm of Wriggleswade... -
Influence of prey abundance and abiotic factors on the long-term home-range and movement dynamics of spotted grunter Pomadasys commersonnii in an intermittently open estuary
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: BA Maree --- Department of Ichthyology and Fisheries Science, South Africa PD Cowley --- Department of Ichthyology and Fisheries Science, South Africa TF Næsje --- South African Institute for Aquatic Biodiversity, South Africa A-R Childs --- Department of Ichthyology and Fisheries Science, South Africa AI Terörde --- Arcus Consulting, South Africa EB Thorstad --- Norwegian Institute for Nature Research, NorwayLong-term home-range and movement dynamics of spotted grunter Pomadasys commersonnii and the distribution of their dominant prey, the sandprawn Callichirus kraussi, were investigated in the intermittently open East Kleinemonde Estuary, South Africa. In addition, the effects of fish length, diel... -
Ocean robotics in support of fisheries research and management
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: S Swart --- Ocean Systems and Climate, South Africa JJ Zietsman --- Defence, Peace, Safety and Security, South Africa JC Coetzee --- Branch: Fisheries Management, South Africa DG Goslett --- Defence, Peace, Safety and Security, South Africa A Hoek --- Sea Technology Services (Pty) Ltd, South Africa D Needham --- Sea Technology Services (Pty) Ltd, South Africa PMS Monteiro --- Ocean Systems and Climate, South AfricaSouth Africa’s small-pelagic fishery is a socio-economically important component of the country’s commercial fisheries sector, second in value only to the demersal trawl fishery. Management of this sector relies on infrequent hydro-acoustic surveys, which provide measures of anchovy Engraulis encrasicolus... -
Estuarine and coastal connectivity of an estuarine-dependent fishery species, Pomadasys commersonnii (Haemulidae)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MH Dames --- Department of Ichthyology and Fisheries Science, South Africa PD Cowley --- South African Institute for Aquatic Biodiversity, South Africa A-R Childs --- Department of Ichthyology and Fisheries Science, South Africa RH Bennett --- South African Institute for Aquatic Biodiversity, South Africa EB Thorstad --- Norwegian Institute for Nature Research, Norway TF Næsje --- Norwegian Institute for Nature Research, NorwayUnderstanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to... -
Space use by Rhabdosargus holubi in a southern African estuary, with emphasis on fish movements and ecosystem connectivity
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GN Grant --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa PD Cowley --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa RH Bennett --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa TS Murray --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa AK Whitfield --- South African Institute for Aquatic Biodiversity (SAIAB), South AfricaTwenty-one juvenile Cape stumpnose Rhabdosargus holubi (140–190 mm fork length) were tagged with internal acoustic transmitters in the lower, middle and upper reaches of the Kowie Estuary, South Africa. The movements of each fish were continually monitored from October 2014... -
Reflection on the first five years of South Africa’s Acoustic Tracking Array Platform (ATAP): status, challenges and opportunities
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: PD Cowley --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa RH Bennett --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa A-R Childs --- Department of Ichthyology and Fisheries Science, South Africa TS Murray --- South African Institute for Aquatic Biodiversity (SAIAB), South AfricaThe Acoustic Tracking Array Platform (ATAP) is a marine science programme that monitors the movements and migrations of inshore marine animals along the South African coastline. Acoustically tagged animals are monitored by an expanded network of approximately 100 automated data-logging... -
Sawn-timber and kraft pulp properties of Pinus elliottii × Pinus caribaea var. hondurensis and Pinus patula × Pinus tecunumanii hybrids and their parental species
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: André Nel --- Shaw Research Centre, Sappi Forests Research, South Africa Francois S Malan --- Retired, South Africa Ron Braunstein --- Sappi Technology Centre, South Africa C Brand Wessels --- Department of Forest and Wood Science, South Africa Arnulf Kanzler --- Shaw Research Centre, Sappi Forests Research, South AfricaA study was undertaken to evaluate the quality of the timber produced by Pinus elliottii × Pinus caribaea var. hondurensis (PECH) and the Pinus patula × Pinus tecunumanii low elevation (PPTL) and high elevation (PPTH) hybrids and their parent species... -
Megabenthos and benthopelagic fishes on Southeast Atlantic seamounts
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: OA Bergstad --- Institute of Marine Research (IMR), Norway M Gil --- Departamento de Ecología y Biología Animal, Edificio de Ciencias Experimentales, Spain ÅS Høines --- Institute of Marine Research (IMR), Norway R Sarralde --- Instituto Espanol de Oceanografia, Centro Oceanografico de Canarias, Spain E Maletzky --- Ministry of Fisheries and Marine Resources, Namibia E Mostarda --- Food and Agriculture Organization of the United Nations (FAO), Italy L Singh --- Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries (DAFF), South Africa MA António --- Secretary of State of Affairs, Ministry of Agriculture, Rural Development and Fisheries, Angola F Ramil --- Departamento de Ecología y Biología Animal, Edificio de Ciencias Experimentales, Spain P Clerkin --- Pacific Shark Research Center (PSRC), Moss Landing Marine Laboratories, United States G Campanis --- South East Atlantic Fisheries Organisation (SEAFO) Secretariat, NamibiaIn a descriptive study of megafauna of several Southeast Atlantic seamounts, multiple video-transects on upper slopes and summits documented the occurrence of benthic invertebrate taxa, primarily corals, regarded as indicators of vulnerable marine ecosystems (VMEs) as defined in international guidelines... -
Using acoustic wave velocity to select fibre-managed plantation Eucalyptus nitens logs for laminated veneer lumber products
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: David Blackburn --- Centre for Sustainable Architecture with Wood (CSAW), School of Architecture and Design, Australia Mario Vega --- Centre for Sustainable Architecture with Wood (CSAW), School of Architecture and Design, Australia Gregory Nolan --- Centre for Sustainable Architecture with Wood (CSAW), School of Architecture and Design, AustraliaThe aims and objectives of this study were to investigate the potential to predict laminated veneer lumber (LVL) stiffness from wood properties measured on trees and logs, and determine variation in log, wood and veneer properties as a function of... -
Using mark-recapture methods to estimate population size and survival of pyjama sharks Poroderma africanum in Mossel Bay, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SP Grusd --- Department of Biological Sciences and the Marine Research Institute, South Africa CL Moloney --- Department of Biological Sciences and the Marine Research Institute, South Africa G Distiller --- Statistics in Ecology, Environment and Conservation (SEEC), Department of Statistical Sciences, South Africa RGA Watson --- Oceans Research, South Africa PD Cowley --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa E Gennari --- Oceans Research, South AfricaThe pyjama shark Poroderma africanum (family Scyliorhinidae) is endemic to coastal waters of South Africa but its population characteristics are poorly known. This study aims to estimate baseline demographic parameters for P. africanum in Mossel Bay. We applied mark-recapture methods... -
To honk or to hiss: uncovering call complexity in the Egyptian Goose Alopochen aegyptiaca
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Tess Gridley --- , South Africa Courtney EC Gardiner --- , South AfricaEgyptian Geese Alopochen aegyptiaca are distributed across most of Africa. Their calls dominate the soundscape of many urban areas, yet their acoustic behaviour is poorly documented or understood. Using acoustic recordings made across a range of behavioural contexts, groups sizes... -
Bull shark Carcharhinus leucas recruitment into the St Lucia Estuary, South Africa, after prolonged mouth closure, and the first observation of a neonate bull shark preyed on by a Nile crocodile Crocodylus niloticus
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Daly --- , South Africa P Le Noury --- , United Kingdom TN Hempson --- , Mozambique M Ziembicki --- , Mozambique JM Olbers --- , South Africa GM Brokensha --- , South Africa BQ Mann --- , South AfricaEstuaries provide critical nursery habitat for juvenile bull sharks Carcharhinus leucas, as they have the ability to withstand a wide range of salinities. St Lucia is the largest estuarine lake in Africa and was once a key nursery for bull... -
An acoustic survey of beaked whale distribution at São Tomé and Príncipe, Gulf of Guinea, using an unmanned surface vessel
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: C Pierpoint --- , United Kingdom E Oliver --- , United Kingdom L Scala --- , United Kingdom D Hedgeland --- , United KingdomThe first records of beaked whales, including Cuvier’s beaked whale Ziphius cavirostris, are reported from an acoustic baseline survey in the territorial waters of the Democratic Republic of São Tomé and Príncipe, Gulf of Guinea, West Africa. The survey was... -
Movement behaviour of catface rockcod Mycteroperca (Epinephelus) andersoni (Epinephelidae) off the eastern seaboard of southern Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: BQ Mann --- , South Africa R Daly --- , South Africa GL Jordaan --- , South Africa WN Dalton --- , South Africa ST Fennessy --- , South AfricaMovement behaviour of the endemic epinephelid Mycteroperca andersoni (formerly allocated to genus Epinephelus) along the east coast of southern Africa was investigated using both conventional dart tagging and passive acoustic telemetry. Results from both methods showed that this species is... -
Fear at the top: killer whale predation drives white shark absence at South Africa’s largest aggregation site
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AV Towner --- , South Africa RGA Watson --- , South Africa AA Kock --- , South Africa Y Papastamatiou --- , United States M Sturup --- , South Africa E Gennari --- , South Africa K Baker --- , South Africa T Booth --- , South Africa M Dicken --- , South Africa W Chivell --- , South Africa S Elwen --- , South Africa T Kaschke --- , South Africa D Edwards --- , South Africa MJ Smale --- , South AfricaRisk-induced fear effects exerted by top predators are pervasive in terrestrial and marine systems, with lasting impacts on ecosystem structure and function. The loss of top predators can disrupt ecosystems and trigger trophic cascades, but the introduction of novel apex... -
Sexual and individual signatures are encoded in the temporal rate of Cape Gannet Morus capensis display calls
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Kezia Bowmaker-Falconer --- , South Africa Andréa Thiebault --- , South Africa Maëlle Connan --- , South Africa Thierry Aubin --- , France Isabelle Charrier --- , France Pierre Pistorius --- , South AfricaVocalisations play a vital role in animal communication, as they are involved in many biological functions such as mate selection, individual recognition and care of young. Seabirds often breed in large and dense colonies, making successful recognition between mates or... -
Call repertoire of Ptychadena uzungwensis (Anura: Ptychadenidae) to complement molecular and morphological identification of the species from the Soutpansberg, South Africa.
Item type: Journal Article • Journal: Treading a Delicate Tightrope: A principal balancing between education and political change during turbulent times • Authors: Ferdi De Lange --- , South Africa Edward C Netherlands --- , South Africa Louis H Du Preez --- , South AfricaThe identity of adults and tadpoles of Ptychadena uzungwensis from the Soutpansberg range in northern South Africa was confirmed using a combination of morphological characters and molecular analysis. Detailed vocalisation analysis was made and used to complement existing species identification... -
Genetic diversity of the mantellid frog Blommersia blommersae, and description of a new anuran species from south-eastern Madagascar
Item type: Journal Article • Journal: Treading a Delicate Tightrope: A principal balancing between education and political change during turbulent times • Authors: Miguel Vences --- , Germany Moritz Armerding --- , Germany Jörn Köhler --- , Germany Frank Glaw --- , GermanyA range-wide assessment of genetic variation in one mitochondrial (16S rRNA) and one nuclear-encoded (Rag-1) gene fragment of the widespread Madagascar frog Blommersia blommersae revealed the presence of up to 12 deep genetic lineages. Many of these differed by genetic... -
Network analysis of the endemic spotted gully shark Triakis megalopterus reveals spatial vulnerability to exploitation in the Western Cape, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: E Cottrant --- , South Africa NJ Drobniewska --- , South Africa TL Johnson --- , South Africa LG Underhill --- University of Cape Town, South Africa TS Murray --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa N Hammerschlag --- University of Miami, United States PS Albano --- University of Miami, United States C Elston --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa ME McCord --- , South Africa PD Cowley --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa C Fallows --- , South Africa TG Paulet --- , South AfricaThe spotted gully shark Triakis megalopterus (Triakidae) is a mesopredatory species endemic to southern Africa. It is currently listed as Least Concern on the IUCN Red List in accordance with an estimated increase in population size, general release by recreational... -
Advertisement call description of the exceedingly rare Phrynomantis affinis (Anura: Microhylidae), with comparisons to P. bifasciatus and range extensions for both species
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Francois S Becker --- National Museum of Namibia, Namibia Alan Channing --- North-West University, South AfricaDespite a relatively broad distribution in Africa, the Spotted Rubber Frog, Phrynomantis affinis, is extremely rarely encountered. Only 18 specimens from 12 localities have been collected with a few additional observations recorded. Virtually nothing of the species’ natural history is... -
Difference in acoustic responses to urbanisation in two African passerines
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Dickson Anobie Matthew --- AP Leventis Ornithological Research Institute (APLORI), Nigeria Samuel Tertse Ivande --- AP Leventis Ornithological Research Institute (APLORI), Nigeria Ulf Ottosson --- AP Leventis Ornithological Research Institute (APLORI), Nigeria Samuel Temidayo Osinubi --- University of Cape Town, South AfricaModification of ecosystems as a consequence of urbanisation alters natural habitat structures and soundscapes, creating constraints for vocal communication in animals. Birds are able to adjust their vocalisation to the prevailing acoustic features of their habitat. As such, their sounds... -
Antagonistic aria: vocalisations of the male slender feather-tailed leaf-toed gecko (Gekkonidae: Kolekanos plumicaudus)
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Francois S Becker --- National Museum of Namibia, Ministry of Education, Arts and Culture, Namibia Pedro Vaz Pinto --- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Portugal Javier Lobón-Rovira --- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, PortugalKolekanos plumicaudus is a gecko endemic to the Namib Desert in south-western Angola. It is distantly related to all other geckos in the region, except for its one congener, K. spinicaudus. There have been no scientific accounts on the social... -
A new Rain Frog (Anura: Brevicipitidae; Breviceps) from the KwaZulu-Natal Midlands, South Africa
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: LH du Preez --- North-West University, South Africa EC Netherlands --- North-West University, South Africa LR Minter --- North-West University, South AfricaBreviceps, an African genus of fossorial frogs, comprises 20 species most of which occur in South Africa. In this study we describe a new species that differs morphologically from its closest congener Breviceps verrucosus, in the position of the mouth... -
Call description and extended range of Phrynobatrachus mayokoensis in Gabon
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Ryan van Huyssteen --- Ecological Services Ltd, British Virgin Islands Melissa Petford --- Ecological Services Ltd, British Virgin Islands Marius Burger --- Ecological Services Ltd, British Virgin Islands Mark-Oliver Rödel --- , Germany Joris Ngoulou --- Ecological Services Ltd, British Virgin Islands Abraham Bamba Kaya --- Ecological Services Ltd, British Virgin Islands Etienne Akomo Okoue --- Ecological Services Ltd, British Virgin Islands Jerome Gaugris --- Ecological Services Ltd, British Virgin IslandsThis study presents the first description of the advertisement call of Phrynobatrachus mayokoensis and reports a new locality record for this species in Gabon. During June 2022, two specimens were found in the Baniaka region, Haut-Ogooué Province, Gabon. The call... -
Comparing seismic survey mitigation regulations: lessons for South Africa from international frameworks
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: J Purdon --- Tshwane University of Technology, South Africa MJ Somers --- University of Pretoria, South Africa FW Shabangu --- University of Pretoria, South Africa Y Doh --- , France J Scheun --- Tshwane University of Technology, South AfricaUnderwater seismic surveys generate high-intensity, low-frequency noise that can negatively affect a range of marine fauna. As a result, countries have implemented mitigation regulations to reduce the potential impacts of this activity. This study examines seismic survey mitigation regulations from... -
Too cold to sing: Warbler dawn chorus affected by environmental factors in a high-elevation wetland
Item type: Journal Article • Journal: African Zoology • Authors: Toka Mosikidi --- University of the Free State, South Africa Nicholas R Friedman --- Leibniz Institute for the Study of Biodiversity Change, Germany Nicholas Le Maitre --- University of the Free State, South Africa Sandy-Lynn Steenhuisen --- University of the Free State, South Africa Vincent Ralph Clark --- University of the Free State, South Africa Kyle John Lloyd --- University of the Free State, South Africa Aliza le Roux --- University of the Free State, South AfricaMany bird species take part in a dawn chorus, the phenomenon in which the community of songbirds in a particular habitat, show a peak of vocal activity around dawn. Understanding the species-specific extrinsic factors affecting this intensive singing activity is... -
Comparing the activity of exploited and unexploited populations of a reef-dwelling seabream, Chrysoblephus laticeps, during an extreme upwelling and cold-spell event
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: NT Mlotshwa --- Rhodes University, South Africa MR Skeeles --- Rhodes University, South Africa MI Duncan --- Rhodes University, South Africa C Muller --- Rhodes University, South Africa WM Potts --- Rhodes University, South Africa AC Winkler --- Rhodes University, South Africa A-R Childs --- Rhodes University, South AfricaAlong the south coast of South Africa, extreme upwelling events lead to rapid temperature declines and prolonged marine cold-spells, which have, on occasion, led to large-scale mortalities of coastal fishes. In a somewhat antagonistic process, fishing exploitation has been shown... -
Unravelling the mystery of a unique giant trevally Caranx ignobilis aggregation in the Mtentu Estuary, Pondoland Marine Protected Area, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: RB Dixon --- Rhodes University, South Africa BQ Mann --- Rhodes University, South Africa TS Murray --- Rhodes University, South Africa PD Cowley --- Rhodes University, South Africa R Daly --- South African Institute for Aquatic Biodiversity (SAIAB), South AfricaThe giant trevally Caranx ignobilis (family Carangidae) is an iconic apex predatory fish valued by recreational and commercial fisheries globally. A seasonal but episodic aggregation of up to ∼1 000 individuals takes place in the Mtentu Estuary in the Eastern... -
Residency, site affinity and coastal movements of the southern African endemic spotted gully shark Triakis megalopterus
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: E Cottrant --- South African Shark Conservancy, South Africa JH Morrison --- South African Shark Conservancy, South Africa C Elston --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa TS Murray --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa NJ Drobniewska --- South African Shark Conservancy, South Africa LG Underhill --- Department of Biological Sciences, University of Cape Town, South Africa N Hammerschlag --- Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, United States PS Albano --- Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, United States ME McCord --- South African Shark Conservancy, South Africa PD Cowley --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa C Fallows --- Apex Shark Expeditions, South Africa TG Paulet --- South African Shark Conservancy, South AfricaRising global concern regarding the conservation and management of shark species makes it essential to identify key ecological species to guide conservation efforts, especially species with more restricted distributions such as endemic species. The southern African endemic spotted gully shark...