The white steenbras (Lithognathus lithognathus), one of South Africa’s most sought after and threatened endemic coastal fishery species, has traditionally been targeted by recreational, subsistence and commercial seine net fishers, and as a result stocks of this species are in a collapsed state. Catch, size and gear restrictions have failed to decrease exploitation or restore spawner biomass levels. Although much is known about its biology, a lack of intimate knowledge on the movement patterns, habitat use and stock integrity, has resulted in difficulties in effective management of this species. The study aims to describe the life-history characteristics, habitat use, movement patterns and genetic diversity of the white steenbras, in South Africa, to provide sound knowledge on which management decisions should be based.

The study will include an assessment of the status of white steenbras stocks in South Africa, using current and historical data, to show trends in catch and effort over the past two decades. Such information will provide insight into the effectiveness of current and historical management measures for the protection of this species. Acoustic telemetry will be used to describe the movement patterns and determine habitat use of juvenile white steenbras within selected South African estuaries, and determine the periodicity and duration of the fishes’ movements between estuarine and marine environments. Such information is essential for estuarine and marine management decisions, and for understanding effects of habitat alteration, degradation or loss and environmental change on the species. Tag-recapture data will be used to determine longshore movement patterns of white steenbras, as well as dispersal from the estuarine environment, along the coastline. Such an understanding of the longshore movement of white steenbras is essential to provide guidelines for management of the species. DNA sequencing will be used to adopt a phylogeographic approach to identify the spatial distribution of genetic diversity within this species.

This study will make use of innovative techniques to investigate the movement patterns, habitat use and habitat connectivity of white steenbras, and the research findings will provide information necessary to assist the corrective management of this over-exploited estuarine-dependent fishery species.

The dusky kob (Argyrosomus japonicus) is an important estuarine-dependent fishery species. High levels of juvenile exploitation in estuaries and habitat degradation has lead to the collapse of the South African dusky kob stock. The current spawner biomass per recruit ratio is only two percent, where 25 to 39 percent constitutes over-exploitation. While the life-history of this species has been studied extensively, large information gaps with regard to spatial and temporal movement dynamics, critical for fisheries management, still exist. This study will make use of innovative techniques, namely acoustic telemetry and otolith microchemistry, and conventional techniques such as mark-recapture, to investigate movement behaviour, estuarine dependency and multiple habitat use of dusky kob. A detailed telemetry study will be conducted in Algoa Bay (Eastern Cape). Sixteen acoustic listening stations will be deployed along the length of the Sundays Estuary to determine estuarine residence and habitat use patterns within the estuarine environment. Additional listening stations will be deployed in the mouths of several adjacent estuaries (Swartkops, Gamtoos, Kromme, Bushmans, Kariega, Kowie, Great Fish) and the Coega and PE Harbour. This will determine multiple habitat use and will quantify the extent of exchange between different estuaries. Fifty juvenile and adult dusky kob (350−1200mm TL) will be tagged with V13 acoustic coded transmitters and will be monitored for a minimum period of one year. Otolith micro-chemical constituent analysis will be conducted on juvenile specimens collected from several estuaries, including the Sundays Estuary, to map the unique chemical fingerprints of these systems (i.e. their natal estuaries) and on larger individuals to identify their estuarine origin and reveal whether they home to their natal estuaries or utilise multiple estuaries throughout ontogeny. Micro-chemical analysis of the strontium/calcium ratio in otoliths will be used to determine ontogenetic changes in habitat use (i.e. life-history use of estuarine and marine environments) and assess the importance of estuaries to dusky kob. This multi-faceted approach to obtain empirical data on the movement dynamics of dusky kob will not only improve our scientific knowledge, but will provide information to assist with the corrective management of this over-exploited estuarine-dependent species.

Lutjanids (snappers) are reef and bottom-associated fish occurring in tropical and sub-tropical marine waters throughout the eastern Pacific, Indo-West Pacific, and western and eastern Atlantic. Fifteen species are known to occur in the South Western Indian Ocean (SWIO). Snappers are a major component of the subsistence fisheries of the Western Indian Ocean countries and contribute substantially to coastal livelihoods.

The aim of the present study is to determine the biogeographic and phylogeographic patterns, and patterns of connectivity in selected lutjanid species (Lutjanus bohar, Lutjanus fulviflamma and Lutjanus lutjanus) in order to understand the origins of diversity and the factors influencing the distributions of diversity in the SWIO. Understanding the processes that affect these species in relation to life history characteristics will provide the knowledge of how each of the species responds to changes in their environment or has responded to historical changes. Such information and an understanding of patterns of connectivity is integral to effective management of these marine resources.

This study will include samples from various regions of the SWIO (including Comoros, Kenya, Madagascar, Mauritius, Mozambique, Reunion, Seychelles, South Africa and Tanzania) and regions on the periphery of the SWIO (e.g., Red Sea, Arabian Peninsula, Maldives and Chagos Islands and Western Australia). These regions were selected to span a range of potential physical and oceanographic barriers, habitats and biogeographic boundaries. DNA sequence data generated from two mitochondrial gene regions (Cytb and ND2) and a nuclear gene will be examined. Data will be analysed under a phylogenetic framework to examine genetic structure, diversity and connectivity among the identified regions, for each of the three species.

Development of a model for optimum economic use of inland fisheries.

Motivation:
Globally, common carp, Cyprinus carpio, is one of the most widely introduced fish species. The life-history traits of carp conform to those predicted for typical successful invaders, so that adverse ecological disruptions are commonplace following carp translocations. On the other hand, carp may significantly contribute to the yield in capture and recreational fisheries and can therefore contribute to food security and tourism, development priorities of South Africa’s rural areas.
Aim:
To provide an assessment of the impact and resource potential of common carp by:
Developing new models to standardise and accurately access catch rates, effort and total yield for common carp by area and sector  (recreational/subsistence);
Understand the biology and population dynamics of common carp;
Comparing life history strategies of common carp and the endemic species, Mudfish Labeo capensis and smallmouth yellowfish Labeobarbus  aeneus; 
Applying meta-analysis to assess the post-impoundment trends of endemic large cyprinids compared to alien carp;
Describing the lake food web dynamics using stable isotope analysis of nitrogen and carbon.

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