Search
Search results for
We found
17 results for you
-
Age and growth of two populations of West Coast steenbras Lithognathus aureti in Namibian waters, based on otolith readings and mark-recapture data
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: J. A. Holtzhausen C. H. KirchnerAge and growth of West Coast steenbras Lithognathus aureti, sampled from two separate populations (northern and southern) along Namibia's coast, was determined using sectioned otoliths, and the results were validated using mark-recapture data. For both populations, the special three-parameter Von... -
AGE, GROWTH, REPRODUCTION AND MORTALITY OF THE BUTTER-CATFISH EUTROPIUS DEPRESSIROSTRIS (SCHILBEIDAE: PISCES) IN THE LUPHEPHE NWANEDZI IMPOUNDHENT, VENDA (SOUTH AFRICA)
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: T. Hecht --- Department of Zoology, South AfricaAspects of the biology of Eutropius depressirostris in the Luphephe-Nwanedzi impoundment in north-east Venda (South Africa 30° 25' E, 23° 14' S) have been investigated. The Von Bertalanffy equation -
Age, growth rate and size at sexual maturity of Labeobarbus aeneus (Teleostei: Cyprinidae) in the middle Vaal River, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: R Gerber --- Centre for Aquatic Research, Department of Zoology, South Africa NJ Smit --- Centre for Aquatic Research, Department of Zoology, South Africa GM Wagenaar --- Centre for Aquatic Research, Department of Zoology, South AfricaAge structure, growth and size at sexual maturity of smallmouth yellowfish, Labeobarbus aeneus (Burchell), were assessed in 2008–2009. Despite its angling and food importance, little has been published on many aspects of its ecology and biology, specifically its age structure... -
Validation of growth zone deposition rate in otoliths and scales of flathead mullet Mugil cephalus and freshwater mullet Myxus capensis from fish of known age
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: BR Ellender --- Department of Ichthyology and Fisheries Science, South Africa GC Taylor --- Department of Ichthyology and Fisheries Science, South Africa OLF Weyl --- , South AfricaFlathead mullet Mugil cephalus and freshwater mullet Myxus capensis are important components in South African estuarine fish communities and fisheries, but there is little information on their age and growth or age validation. This study validated the periodicity of growth... -
Age estimation, growth rate and size at sexual maturity of tigerfish Hydrocynus vittatus from the Okavango Delta, Botswana
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: R Gerber --- Centre for Aquatic Research, Department of Zoology, South Africa NJ Smit --- Centre for Aquatic Research, Department of Zoology, South Africa GM Pieterse --- Centre for Aquatic Research, Department of Zoology, South Africa D Durholtz --- , South AfricaThe aims of this study were to determine relative age, growth rate and size at maturity of tigerfish in the Okavango Delta as a basis for the development of a fisheries management plan. A total of 206 tigerfish Hydrocynus vittatus,... -
Otoliths and vertebrae as potential hard structures for ageing South African yellowfin tuna Thunnus albacares
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JD Filmalter --- Department of Ichthyology and Fisheries Science, South Africa OLF Weyl --- Department of Ichthyology and Fisheries Science, South Africa W Sauer --- Department of Ichthyology and Fisheries Science, South AfricaSagittal otoliths and vertebrae from 46 yellowfin tuna Thunnus albacares (118-175 cm fork length) collected off the west coast of South Africa were assessed for potential usefulness in age estimation. Growth increments were found on both structures. Comparisons of growth... -
A morphological description of the sagittal otoliths of two mormyrids, Marcusenius macrolepidotus and Petrocephalus catostoma (Family: Mormyridae)
Item type: Journal Article • Journal: African Zoology • Authors: N.N. Nicolaai --- Department of Zoology and Biology, South Africa A. Jooste --- Department of Zoology and Biology, South AfricaThe morphology of the sagittal otoliths of two South African mormyrid fish, Marcusenius macrolepidotus and Petrocephalus catostoma, were studied to determine possible morphological significance. The sagittae of M. macrolepidotus and P. catostoma are kidney-shaped and oblong, respectively. The ventral margin... -
Age and growth of the estuarine-dependent sparid Acanthopagrus berda in northern KwaZulu-Natal, South Africa
Item type: Journal Article • Journal: African Zoology • Authors: N. C. James --- Oceanographic Research Institute, South Africa B. Q. Mann --- Oceanographic Research Institute, South Africa L. E. Beckley --- Oceanographic Research Institute, South Africa A. Govender --- Oceanographic Research Institute, South AfricaAges were estimated for the tropical sparid, Acanthopagrus berda, caught in northern KwaZulu-Natal estuaries. Whole otoliths were used in the age determination. Age estimates were validated by marginal increment analysis and oxytetracycline labelling, which indicated that opaque deposition occurs primarily... -
Otoliths versus scales: evaluating the most suitable structure for ageing largemouth bass, Micropterus salmoides, in South Africa
Item type: Journal Article • Journal: African Zoology • Authors: G.C. Taylor --- Department of Ichthyology and Fisheries Science, South Africa O.L.F. Weyl --- Centre for Invasion Biology, South African Institute for Aquatic Biodiversity, South AfricaThe suitability of scales for ageing Micropterus salmoides was determined by comparing the precision of growth zone counts on scales with those obtained from sectioned sagittal otoliths from a sample of 496 fish collected from Wriggleswade and Mankazana Impoundments in... -
Insights into the diet of a poorly known species: pygmy killer whale Feresa attenuata from Cape Verde, West Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: PR O'Dwyer --- Marine Biodiversity Research Group, Ireland S Berrow --- Marine Biodiversity Research Group, Ireland P López-Suárez --- Bios, C Oujo Lamao --- Bios,Despite having a worldwide distribution in tropical waters, knowledge on pygmy killer whales Feresa attenuata, including diet, is poor, with only a few studies carried out to date. The presence of otoliths and beaks in stomachs that have been examined... -
Age and growth of Cape stumpnose Rhabdosargus holubi (Pisces: Sparidae) in the Eastern Cape, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MW Farthing --- Department of Ichthyology and Fisheries Science, South Africa NC James --- South African Institute for Aquatic Biodiversity, South Africa WM Potts --- Department of Ichthyology and Fisheries Science, South AfricaRhabdosargus holubi is a small (maximum weight=2.4 kg) yet important fishery species in the estuaries of the south-east coast of South Africa. Little is known of its biology and specifically its growth rate, which is essential for sustainable management of the... -
Otolith shape as a valuable tool to evaluate the stock structure of swordfish Xiphias gladius in the Indian Ocean
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: K Mahé --- Ifremer, Laboratoire Ressources Halieutiques, France H Evano --- Ifremer, Délégation Océan Indien, France T Mille --- Ifremer, Laboratoire Ressources Halieutiques, France D Muths --- Université Européenne de Bretagne, France J Bourjea --- , FranceSwordfish Xiphias gladius is an oceanic-pelagic species. Its population structure in the Western Indian Ocean was studied from the shape of the sagittal otoliths of 391 individuals collected from 2009 to 2014. Normalised elliptical Fourier descriptors (EFDs) were extracted automatically... -
Age and growth of redeye round herring Etrumeus whiteheadi off the South African coast
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: Y Geja --- Branch Fisheries Management, Department of Agriculture, Forestry and Fisheries, South Africa MD Durholtz --- Branch Fisheries Management, Department of Agriculture, Forestry and Fisheries, South Africa CL Moloney --- Zoology Department and Marine Research Institute, South AfricaAges of redeye round herring Etrumeus whiteheadi were estimated with associated errors and used to infer life-history information, such as age composition, age-at-maturity and instantaneous mortality rate. Samples were collected in November 2005 during a research survey aimed at estimating... -
The age and growth of hottentot seabream Pachymetopon blochii before and after the South African linefish state of emergency in 2000
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MW Farthing --- Department of Ichthyology and Fisheries Science, South Africa AC Winkler --- Department of Ichthyology and Fisheries Science, South Africa K Anderson --- Department of Ichthyology and Fisheries Science, South Africa S Kerwath --- Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries (DAFF), South Africa C Wilke --- Branch: Fisheries Management, Department of Agriculture, Forestry and Fisheries (DAFF), South Africa WM Potts --- Department of Ichthyology and Fisheries Science, South AfricaThe hottentot seabream Pachymetopon blochii is a small-sized (maximum 2.67 kg) sparid endemic to southern Africa. It is an important target in South Africa's Western Cape traditional linefishery, particularly in the absence of more valuable pelagic species (such as Thyrsites... -
Fifty-five-year longevity for the largest member of the family Sparidae: the endemic red steenbras Petrus rupestris from South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AH Andrews --- , United States MJ Smale --- , South Africa PD Cowley --- , South Africa N Chang --- , South AfricaA previous study that explored the age and growth of red steenbras Petrus rupestris (Valenciennes, 1830), a large sparid (family Sparidae, seabreams or porgies) endemic to South Africa and reported to approach 2 m in length, provided estimates as a... -
Life-history traits of seabream Boops boops (Linnaeus, 1758) in the central eastern Atlantic Ocean (Canary Islands)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: A Massaro --- , Italy JG Pajuelo --- , SpainLife-history traits of the sparid Boops boops are studied for the first time in an isolated Atlantic population. Boops boops is a hermaphrodite species characterised by late gonochorism or non-functional hermaphroditism. The 1:0.852 ratio of females to males was significantly... -
Age and growth of the Cape knifejaw Oplegnathus conwayi, an endemic South African teleost
Item type: Journal Article • Journal: African Zoology • Authors: RM Foster --- , South Africa A-R Childs --- , South Africa BQ Mann --- , South Africa WM Potts --- , South AfricaThe South African spearfishery targets a variety of data-deficient species, which are consequently poorly managed. This study aimed to describe the age and growth of one of these species, the Cape knifejaw, Oplegnathus conwayi, which is endemic to the southern...