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A comparison of condition factor and gonadosomatic index of sardine Sardinops sagax stocks in the northern and southern Benguela upwelling ecosystems, 1984–1999
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: A. Kreiner C. D. van der Lingen P. FréonTime-series of condition factor (CF) and gonadosomatic index (GSI) were generated using general linear models (GLM) for sardine Sardinops sagax stocks in the northern and southern Benguela ecosystems over the period 1984–1999. During this period the biomass of sardine in... -
COMPARISON OF FISH GONADS AND FISH MEAL AS MAJOR COMPONENTS IN THE DIETS OF YOUNG AFRICAN SHARPTOOTH CATFISH, CLARIAS GARIEPINUS (BURCHELL)
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: L.C. Hoffman --- Aquaculture Research Unit, South Africa J.F. Prinsloo --- Aquaculture Research Unit, South Africa J. Theron --- Aquaculture Research Unit, South AfricaThe replacement of fish-meal (two sources, arbitrarily designated FMA and FMB), with either freeze dried (GVD) or oven dried (GOD) gonads of Clarias gariepinus in a starter diet for larvae of this species, was tested. No significant difference in larval... -
SOME ASPECTS OF THE REPRODUCTION BIOLOGY OF LABEO CAPENSIS (SMITH, 1941) (PISCES, CYPRINIDAE) IN RELATION TO EXPLOITATION AND EXTREME ENVIRONMENTAL CONDITIONS IN HARDAP DAM, NAMIBIA
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: B.J. Van Zyl --- Department of Zoology, Research Unit for Aquatic and Terrestrial Ecosystems, South Africa C.J. Hay --- Department of Zoology, Research Unit for Aquatic and Terrestrial Ecosystems, South Africa G.J. Steyn --- Department of Zoology, Research Unit for Aquatic and Terrestrial Ecosystems, South AfricaThe sex ratio of Labeo capensisdid not differ significantly at a 95% confidence level from a 1♂:1♀, ratio during the study period. The smallest sexually mature male and female L. capensis were 20 cm and 21 cm FL, respectively. Fifty... -
Histological studies to evaluate gonad development in Barbus neefi (Cyprinidae), the sidespot barb, from South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: W VlokBarbus neefi gonads were collected seasonally from specimens from the Selati and Makutsi Rivers, tributaries of the Olifants River in Limpopo and Mpumalanga provinces, South Africa, preserved in 4% formalin solution and stained with hematoxilin/eosin. These collections represent new records... -
Differentiated gonochorism in Nile perch Lates niloticus from Lake Victoria, Uganda
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: RK Basiita --- , Uganda C Aruho --- , Uganda D Kahwa --- , Uganda E Nyatia --- , Uganda FW Bugenyi --- Department of Zoology, Uganda J Rutaisire --- , UgandaGonadal development and structure were examined in 317 Nile perch, Lates niloticus, of 4 to 157 cm SL taken from Lake Victoria, Uganda, in 2005–2006. Macroscopic and histological investigation showed a differentiated gonochoristic pattern, with no juvenile intersexuality. Oogonial cells... -
The breeding biology of the southern barred minnow Opsaridium peringueyi (Gilchrist and Thompson 1913) in the Incomati and Luvuvhu river systems, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: PSO Fouché --- Zoology Department, South Africa JA Venter --- School of Biological and Conservation Sciences, South AfricaData collected at two sites in the Luvuvhu and Sabie rivers show that, based on the gonadosomatic index, Opsaridium peringueyi has one major annual breeding event that occurs in early summer, following a period during which the general condition of... -
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... -
Reproductive biology of horse mackerel Trachurus capensis and Trachurus trecae in Namibia and Angola
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HON Ndjaula --- Department of Biology, Norway J-O Krakstad --- , Norway OS Kjesbu --- , NorwayHarvest control measures for Namibia and Angola are defined using reference points for spawning biomass, which requires knowledge of spawning potential and dynamics of fishery stocks. The reproductive biology of two species of horse mackerel, Trachurus capensis and Trachurus trecae,... -
Diagnosing the sexual pattern of Diplodus cervinus hottentotus (Pisces: Sparidae) from southern Angola
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: AC Winkler --- Department of Ichthyology and Fisheries Science, South Africa CV Santos --- Faculdade Ciências da Universidade Agostinho Neto (FCUAN), Angola WM Potts --- Department of Ichthyology and Fisheries Science, South AfricaThe sexual pattern of Diplodus cervinus hottentotus was investigated in southern Angola. Females were significantly smaller and found in greater numbers, with an adult sex ratio of 1.0:0.7, F:M. Histological observations of preserved gonads indicated that the species is a... -
Maturity, spermatogenesis and seasonal reproductive cycle of male Rhinobatos annulatus (Muller & Henle, 1841) from Algoa Bay, South Africa, and a novel description for sperm release from the spermatocyst
Item type: Journal Article • Journal: African Zoology • Authors: G.J. Rossouw --- Department of Zoology, South AfricaDespite the unique gonadal organization and reproductive strategies known for elasmobranchs very little is known about the reproductive biology of local species. The stages of spermatogenesis for the lesser guitar fish, Rhinobatus annulatus, has not been described and specifically the... -
The prevalence and association of low testosterone levels in a South African male, diabetic, urban population
Item type: Journal Article • Journal: Journal of Endocrinology, Metabolism and Diabetes of South Africa • Authors: Tanja Kemp --- Department of Internal Medicine, South Africa Paul Rheeder --- Department of Internal Medicine, South AfricaBackground: According to the literature, low serum testosterone levels are associated with diabetes mellitus. No or minimal data exist for its prevalence or predictors in South Africa. -
The reproductive biology of an open-water spawning Lake Malawi cichlid, Copadichromis chrysonotus
Item type: Journal Article • Journal: African Zoology • Authors: Lance W. Smith --- Research Officer, MalawiCopadichromis chrysonotus is a zooplanktivorous cichlid member of the diverse fish community inhabiting Lake Malawi’s rocky, littoral habitat. Like most Lake Malawi cichlids, this species’ reproductive strategy is based on maternal mouthbrooding, but it is the only littoral species known... -
Histological validation of gonadal macroscopic staging criteria for Labeo cylindricus (Pisces: Cyprinidae)
Item type: Journal Article • Journal: African Zoology • Authors: Anthony J. Booth --- Department of Ichthyology and Fisheries Science, South Africa Olaf L.F. Weyl --- Department of Ichthyology and Fisheries Science, South AfricaHistological examination of gametogenesis revealed that the current staging criteria used to assess gonadal recrudescence of the redeye labeo, Labeo cylindricus, were adequate. Gametogenesis was qualitatively similar to thatof freshwater teleosts with a clearly defined seasonal reproductive cycle. L. cylindricus... -
Changes in the abundance of cells in the anterior pituitary gland and the possible roles of luteinizing hormone, prolactin and progesterone in the control of delayed implantation in the straw-coloured fruit bat (Eidolon helvum)
Item type: Journal Article • Journal: African Zoology • Authors: J.A. Simbauni --- Kenyatta University, Kenya R.T.F. Bernard --- Department of Zoology & Entomology, South AfricaEidolon helvum (Megachiroptera) is a large frugivorous bat found in equatorial and tropical Africa. The reproductive cycle is characterized by a three-month period of delayed implantation and the total length of pregnancy may be as much as 10 months. A... -
Structure and cytology of the testes of Labeo victorianus (Pisces: Cyprinidae)
Item type: Journal Article • Journal: African Zoology • Authors: Justus Rutaisire --- Department of Wildlife and Animal Resources Management, Uganda Ruth T. Muwazi --- Department of Wildlife and Animal Resources Management, Uganda Anthony J. Booth --- Department of Ichthyology and Fisheries Science, South AfricaTestes macromorphology and histomorphology together with sperm cytology are described for a potamodrometic cyprinid fish, Labeo victorianus, from Lake Victoria. Testes were found to be paired and elongate, suspended by a mesorchium on either side of the swim bladder. A... -
An assessment of the reproductive biology of the Marico barb Barbus motebensis from the upper Groot Marico catchment, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D Kindler --- Department of Zoology, South Africa GM Wagenaar --- South African Institute for Aquatic Biodiversity (SAIAB), South Africa OLF Weyl --- Centre for Invasion Biology, SAIAB, South AfricaBarbus motebensis is endemic to the Groot Marico River catchment in the North West province, South Africa, and is considered of particular conservation importance due to being Red-Listed as Vulnerable. Due to its vulnerable conservation status, the aim of this... -
Mytilus galloprovincialis (Mollusca: Bivalvia) in a warm-temperate South African estuarine embayment
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: M Pollard --- Department of Zoology and Entomology, Knysna Basin Project, South Africa AN Hodgson --- Department of Zoology and Entomology, Knysna Basin Project, South AfricaThe distribution, population structure, condition and gonad indices, and the attachment strengths of the invasive Mediterranean mussel Mytilus galloprovincialis are described from the Knysna Estuary, South Africa. Mussels were found in the rocky intertidal at the mouth of the estuary... -
Aspects of reproduction of the brown mussel Perna perna at the Iture rocky beach near Cape Coast, Ghana
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: EA Krampah --- Department of Fisheries and Aquatic Sciences, Ghana K Yankson --- Department of Fisheries and Aquatic Sciences, Ghana J Blay --- Department of Fisheries and Aquatic Sciences, GhanaAspects of the reproductive biology of the brown mussel Perna perna at the Iture rocky beach near Cape Coast, Ghana, were studied from September 2014 to August 2015. The current study was aimed at providing information useful for managing the... -
Effects of marine reserves on the reproductive biology and recruitment rates of commonly and rarely exploited limpets
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MDV Nakin --- Biological and Environmental Sciences Department, South Africa CD McQuaid --- Coastal Research Group, Department of Zoology and Entomology, South AfricaWe tested the effects of marine reserve status on the reproductive biology and recruitment rates of two commonly exploited (Helcion concolor, Scutellastra longicosta) and two rarely exploited (Cellana capensis, Scutellastra granularis) limpet species using two reserve and two non-reserve sites... -
Health effects in fish from the polluted Orlando Dam and Klipspruit wetland system, Soweto, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: TS Bengu --- Department of Geography, South Africa J du Plessis --- Department of Zoology, South Africa LS Modley --- Department of Geography, South Africa JC van Dyk --- Department of Zoology, South AfricaPollution of aquatic ecosystems often results in adverse environmental disturbances, including physiological and/ or histomorphological changes in fish. The health of Clarias gariepinus sampled from two polluted water bodies, Orlando Dam and a pond in the Klipspruit wetland catchment, Soweto,... -
Reproductive strategies of smooth-head catfish Clarias liocephalus (Boulenger, 1898), in the Rwizi-Rufuha wetland system, south-western Uganda
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: J Yatuha --- Biology Department, Uganda J Rutaisire --- National Agricultural Research Organization, Uganda L Chapman --- Department of Biology, Canada J Kang’ombe --- Bunda College of Agriculture, Malawi D Sikawa --- Bunda College of Agriculture, MalawiThe reproduction of the smooth-head catfish (Clarias liocephalus), a heavily exploited wetland fish in Uganda, in a data-deficient fishery, was studied from January to December 2011. Analyses were based on a sample of 854 fish specimens obtained from a chain... -
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... -
Hypogonadism and associated risk factors in male patients with type 2 diabetes mellitus attending the diabetic clinic of Tikur Anbessa Specialized Teaching Hospital, Addis Ababa, Ethiopia
Item type: Journal Article • Journal: Journal of Endocrinology, Metabolism and Diabetes of South Africa • Authors: Sisay Teka --- College of Medicine and Health Sciences, Ethiopia Samuel Kinde --- College of Health Sciences, Addis Ababa University, Ethiopia Gobena Dedefo --- College of Health Sciences, Addis Ababa University, Ethiopia Kissi Mudi --- Ethiopian Public Health Institute, Ethiopia Getahun Tarekegn --- Tikur Anbesa Specialized Teaching Hospital, EthiopiaBackground: A high prevalence of hypogonadism among men with type 2 diabetes mellitus (T2DM) has been reported worldwide. This in turn creates a substantial public health burden in terms of inadequate sexual function and potential infertility. However, the status of... -
Describing gonad development and gametogenesis in southern Africa’s endemic box jellyfish Carybdea branchi (Cubozoa, Carybdeidae)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Mohamed --- Department of Biodiversity and Conservation Biology, South Africa H Skrypzeck --- Department of Biodiversity and Conservation Biology, South Africa MJ Gibbons --- Department of Biodiversity and Conservation Biology, South AfricaInformation on the reproductive development of species of box jellyfish (class Cubozoa) is poor globally, despite their significance as potent stingers and worrying projections about range expansions. While most species are confined to tropical and subtropical waters, the South African... -
First record of Labeo capensis (Smith, 1841) in the Crocodile River (West) system: another successful non-native freshwater fish introduction in South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: JH Erasmus --- Water Research Group, Unit for Environmental Sciences and Management, South Africa W Malherbe --- Water Research Group, Unit for Environmental Sciences and Management, South Africa R Gerber --- Water Research Group, Unit for Environmental Sciences and Management, South Africa OLF Weyl --- DST/NRF Research Chair in Inland Fisheries and Freshwater Ecology, South Africa B Sures --- Aquatic Ecology and Centre for Water and Environmental Research, Germany V Wepener --- Water Research Group, Unit for Environmental Sciences and Management, South Africa NJ Smit --- Water Research Group, Unit for Environmental Sciences and Management, South AfricaSouth Africa is one of six global fish invasion hotspots and as a result, non-native fishes are common components of the fish assemblages in all of the major river systems. The rate of establishment for introduced fish into South African... -
Acute changes in haematocrit leading to polycythaemia in late-onset hypogonadism patients that receive testosterone replacement therapy: a South African study
Item type: Journal Article • Journal: Journal of Endocrinology, Metabolism and Diabetes of South Africa • Authors: Jesslee du Plessis --- Medicine Usage in South Africa (MUSA), North-West University, South Africa Hermanus Lambertus Bester --- Private Hospital, Emalahleni, South Africa, Marlene Julyan --- Medicine Usage in South Africa (MUSA), North-West University, South Africa Marike Cockeran --- School for Computer, Statistical and Mathematical Sciences, North-West University, South AfricaBackground: According to the literature, parenteral testosterone replacement therapy (TRT)-induced polycythaemia is associated with cardiovascular events. No or minimal data exist for the prevalence of TRT-induced polycythaemia in late-onset hypogonadism (LOH) patients from South Africa. Polycythaemia is the side effect... -
Preliminary observations of the reproductive biology of the Frenchman seabream Polysteganus baissaci (Sparidae) from Mauritius
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Caussy --- Department of Biosciences and Ocean Studies, Faculty of Science, Mauritius C Appadoo --- Department of Biosciences and Ocean Studies, Faculty of Science, Mauritius WHH Sauer --- Department of Ichthyology and Fisheries Science, South Africa WM Potts --- Department of Ichthyology and Fisheries Science, South AfricaThe Frenchman seabream Polysteganus baissaci is an important commercial fish species found on the slopes of the fishing banks of the exclusive economic zone of Mauritius. Exploitation of this species started in 2007, and it is targeted using hydraulic reels... -
Reproductive biology of the mackerel scad Decapterus macarellus from Cabo Verde and the implications for its fishery management
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MPV Costa --- Instituto Nacional do Desenvolvimento das Pescas [National Institute for Fisheries Development ] (INDP), Cabo Verde DRS Cruz --- Faculty of Sciences of the University of Lisbon, Portugal LS Monteiro --- Federal University of Rio Grande, Brazil KSM Evora --- University of Cabo Verde, Cabo Verde LG Cardoso --- Federal University of Rio Grande, BrazilThe mackerel scad Decapterus macarellus is of great social and economic importance to Cabo Verde citizens; however, in recent years catches have shown an unexplained decline. The harvest is regulated by way of a minimum legal size and a seasonal... -
Gonadal development and intersex condition of marbled lungfish, Protopterus aethiopicus (Heckel, 1851), in contaminated sites in Lake Victoria, Uganda
Item type: Journal Article • Journal: African Zoology • Authors: Inuwa Badamasi --- , Uganda Robinson Odong --- , Uganda Charles Masembe --- , UgandaThe first evidence of the impact of environmental contamination on populations of Protopterus aethiopicus (Heckel, 1851) in terms of body indices, cellular development (histology) and intersex condition in Lake Victoria, Uganda is provided. Specimens were obtained from the more polluted... -
Size at maturity, maturity stages and sex ratio of tigerfish Hydrocynus vittatus Castelnau, 1861 in Lake Kariba, Zimbabwe: assessing the influence of decades of fisheries exploitation
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Terence Magqina --- , Zimbabwe Tatenda Dalu --- , South Africa Lindah Mhlanga --- , Zimbabwe Tamuka Nhiwatiwa --- , ZimbabweSize at maturity, sex ratio and maturity stages are key population parameters in fisheries management of exploited stocks because they influence survival of fish populations. The decline in Hydrocynus vittatus catches during the tigerfish competition and along the shoreline of... -
Spawning observations of Pomadasys commersonnii in the marine section of the Knysna estuarine bay, Western Cape, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: EC Butler --- , South Africa A-R Childs --- , South Africa MKS Smith --- , South Africa RM Foster --- , South Africa WM Potts --- , South AfricaKnowledge of the location and timing of spawning events is critical for fisheries management. As is the case for many southern African fishes, the spotted grunter Pomadasys commersonnii was historically thought to reproduce in the coastal waters off KwaZulu-Natal Province... -
Maturity length, fecundity and spawning season of Atlantic chub mackerel Scomber colias in the coastal waters of Ghana (west-central Gulf of Guinea)
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JE Kassah --- University of Cape Coast, Ghana J Blay --- Centre for Coastal Management (Africa Centre of Excellence in Coastal Resilience), University of Cape Coast, Ghana I Okyere --- University of Cape Coast, Ghana N Lazar --- University of Rhode Island, United StatesAspects of the reproductive biology of Atlantic chub mackerel Scomber colias are reported here based on data from random samples of artisanal fish landings from Ghana. The specimens were between 13.7 cm and 40.7 cm total length (TL), and both... -
The ecology of coastal wetland ponds created by diamond mining in southern Namibia. 3. Fish
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Maritz --- University of Cape Town, South Africa CG Attwood --- University of Cape Town, South Africa D Pillay --- University of Cape Town, South Africa GM Branch --- University of Cape Town, South AfricaDiamond mining in southern Namibia creates seawalls that hold the ocean at bay, yet seawater overwashes or seeps through to fill landward excavated areas, forming numerous coastal ponds that reach 380 000 m2. These ponds span ages of 1–40 years,... -
Effect of altitudinal gradient on reproductive and feeding behaviours of four congeneric endemic freshwater fish in the Zat Catchment (Morocco)
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: A Ahnich --- Polydisciplinary Faculty, Sultan Moulay Slimane University, Morocco F Aitboumalassa --- Polydisciplinary Faculty, Sultan Moulay Slimane University, Morocco H Khalki --- Polydisciplinary Faculty, Sultan Moulay Slimane University, Morocco M Naimi --- Polydisciplinary Faculty, Sultan Moulay Slimane University, MoroccoThe adaptive capacity of freshwater fish enables them to undergo morphological and structural changes in response to environmental fluctuations. Documenting these responses is crucial to assess species vulnerability to ecological perturbations. This study investigated the reproductive, feeding and physiological adaptations... -
Spatial and temporal distribution of shallow-water hake Merluccius capensis off the south coast of South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: LCJ Nomxego --- Fisheries and the Environment (DFFE), South Africa OS Kjesbu --- Institute of Marine Research, Norway WHH Sauer --- Rhodes University, South Africa MR Lipinski --- Rhodes University, South AfricaThis study investigated the spatial and temporal distribution of shallow-water hake Merluccius capensis off the south coast of South Africa, using 1 807 females collected by bottom trawling during industry and research surveys between 2014 and 2016. Mean body size...