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For manufactured nanomaterials (MNs), given the breadth of forms produced, it is not ethical or practical to test all materials using vertebrates. This study aimed to show how alternative methods could predict the in vivo bioaccumulation potential of MNs in fish. This included exploring the physico-chemical properties of MNs as predictors of bioaccumulation, using the ex vivo gut sac technique to measure total metal uptake, and an in chemico digestibility assay to simulate the bioaccessible metal in the gut lumen of fish. An apparent plateau in net metal accumulation by rainbow trout was evident from data on dietary exposures to CuO nanoparticles (NPs), Ag NPs or Ag2S NPs in vivo. From the metal concentrations in the tissues compared to the diet, it was possible to derive nano biomagnification factors (nBMFs). The nBMF for the liver showed the best correlations with the physico-chemical parameters, with a significant correlation to the particle dissolution rate (Spearman's correlation, p < 0.01). Moreover, there was a significant relationship between the total metal released in the stomach compartment of the digestibility assay and the total metal concentration in the liver of trout in vivo (Pearson's correlation coefficient, p = 0.02), suggesting the in chemico digestibility assay can predict bioaccumulation potential. The ex vivo gut sac technique also gave good correlations to in vivo results, with r2 values between 0.8–0.9. In conclusion, the meta-analyses supports the development of an integrated and tiered approach to bioaccumulation testing that considers the 3Rs (replacement, reduction, refinement) and minimises the use of the fish bioaccumulation test (OECD TG 305), for nanomaterials.

Freshwater recreational angling is growing in popularity internationally. Due to the potential negative environmental impacts, various regulatory systems exist. In South Africa, freshwater recreational angling is regulated through a complex legal framework, consisting of national and provincial legislation dating back to the 1960s.The legislation also relates to historical and current provincial boundaries, adding to the regulatory complexity. Due to this complexity, the question arises whether freshwater recreational bank anglers in South Africa are aware of the regulatory requirements applicable to them. Low levels of awareness could lead to non-compliance, which would suggest an ineffective regulatory system. The aim of this research was thus to determine the environmental regulatory awareness of freshwater recreational bank anglers in South Africa. This was achieved through a literature review of national and provincial legislation, as well as the rules applicable to organised freshwater recreational bank angling. An online survey was completed by 100 members of the South African Freshwater Bank Angling Federation (SAFBAF). The results of the survey ndicate that the regulatory awareness of the sample of SAFBAF freshwater recreational anglers is low in certain key areas, such as bag and size limits for specific fish species, catch and release requirements, as well as legal definitions for alien and invasive and TOPS species listings. However, the low level of awareness can be ascribed to the complex regulatory system and not unwillingness of anglers to comply per se. It is recommended that (i) a single consolidated and simplified regulatory system for freshwater recreational bank angling be developed, and (ii) that angling organisational and competition rules be aligned with relevant regulatory requirements, to improve overall awareness and promote higher levels of regulatory compliance.

Southern Africa has one of the highest densities of temporary pools and some of the most understudied temporary wetlands in the world. Additionally, the eastern African annual killifishes (Nothobranchius spp.) are rare in southern Africa and found exclusively in temporary habitats. There is a notable lack of literature regarding the diet of these fish, as well as the foodweb structures of temporary ecosystems. The current study aimed to address this paucity in literature by assessing the foodweb of a temporary pool located in the Ndumo Game Reserve (NGR) in northern Kwa-Zulu Natal using stable isotopes analysis. In addition, Bayesian mixing models were used to assess the diet of the spotted killifish Nothobranchius orthonotus over two seasons (dry and wet seasons). The foodweb consisted of only three trophic levels and comprised different foodweb items between the two seasons. Stable isotope analysis indicated significant increases in δ15N from the dry to wet season. It further revealed the diet of N. orthonotus to be more varied and omnivorous with primary producers contributing a much greater percentage toward their diet than previous studies have reported. This study contributes valuable information to the paucity of knowledge regarding foodweb structure and food-chain length of temporary pools in South Africa, as well as new insights into the extended diet of N. orthonotus. The analytical techniques used in this study could also be utilised as part of future research in ecological assessments of temporary pools and other aquatic ecosystems in Africa and globally

South Africa is the world’s main supplier of Pt. The Bushveld Igneous Complex in South Africa contains 75% of the world’s Pt resources. Mining of this precious metal requires large volumes of water for production and removal of waste products. Most of this wastewater is discharged into river systems. Although the source of contamination with Pt in aquatic systems due to mining activities is known, little to no information is available about the impact of Pt on aquatic organisms. Additionally, other metals are released as byproducts of Pt mining, which might also be discharged into the environment. Therefore, concentrations of Cr, Ni, Cu, Zn, Cd, Pt and Pb were determined in water, sediment and macroinvertebrate samples from a reference site (Site 1), a highly impacted site (Site 2) and a moderately impacted site (Site 3) along the Hex River, South Africa. Aquatic invertebrate families representing different functional feeding groups i.e. scraper-grazers (Lymnaeidae), collector-gatherers (Potamonautidae, Hydropsychidae, Tubificidae and Chironomidae), shredders (Baetidae) and predators (Coenagrionidae and Libellulidae) were studied. In the sediments, the concentrations of Cr and Pt were significantly higher at Site 2 than at Sites 1 and 3, respectively, whereas concentrations of Ni, Cu, Cd, and Pb showed no significant differences between the sites. Depending on the metal, the aquatic invertebrate families showed different grades of bioaccumulation. The results from especially Lymnaeidae, Baetidae, Tubificidae and Chironomidae showed great promise for the use of these taxa for biomonitoring of metal contaminations. The macroinvertebrates accumulated metals associated with Pt mining, with epi-benthic dwelling taxa (Tubificidae) accumulating higher concentrations of Pt and Cr than other families (e.g. Potamonautidae, Coenagrionidae and Lymnaeidae). These results provide valuable information on the behavior of metals related to Pt mining in aquatic ecosystems and therefo

Although temporary wetlands are often biodiversity hotspots that deliver multiple ecosystem services, they are also threatened by human exploitation. We conducted a comparative field study to investigate the impact of reserve protection on the diversity and community structure of aquatic macroinvertebrates of temporary wetlands (pans) in South Africa. Specifically, we compared the diversity and community composition of macroinvertebrates with a special focus on large branchiopod crustaceans in pans of a protected nature reserve (Ndumo Game Reserve) with that of pans in the surrounding anthropogenically disturbed area (Ndumo Communal Area). Our results show that reserve protection has a significant positive effect on the diversity and community structure of the aquatic macroinvertebrates. The taxon diversity for macroinvertebrates in general and large branchiopods in particular was significantly higher in the Ndumo Game Reserve, compared with the Ndumo Communal Area. Overall, our results illustrate the need for continued protection of reserve areas and pans in this tropical region in South Africa for the conservation of macroinvertebrate species

Caenorhabditis elegans presents functioning, biologically relevant phenotypes and is frequently used as a bioindicator of toxicity. However, most C. elegans in vivo effect-assessment methods are laborious and time consuming. Therefore, we developed a novel method to measure the oxygen consumption rate of C. elegans as a sublethal endpoint of toxicity. This protocol was tested by exposing 50 larval stage one C. elegans individuals for 48 h (at 20 °C) to different concentrations of two toxicants i.e. benzylcetyldimethylammonium chloride (BAC-C16) and cadmium (Cd). Following exposures, the oxygen consumption rate of the C. elegans individuals were measured using the high-throughput functionality of the Seahorse XFe96 Extracellular Flux Analyzer. Dose-response curves for BAC-C16 (R2 = 0.93; P = 0.001) and Cd (R2 = 0.98; P = 0.001) were created. Furthermore, a strong, positive correlation was evidenced between C. elegans oxygen consumption rate and a commonly used, ecologically relevant endpoint of toxicity (growth inhibition) for BAC-C16 (R2 = 0.93; P = 0.0001) and Cd (R2 = 0.91; P = 0.0001). The data presented in this study show that C. elegans oxygen consumption rate can be used as a promising functional measurement of toxicity

South Africa is in the process of developing a National Freshwater (Inland) Wild Capture Fisheries Policy. A properly focused research strategy is essential to guide the policy development process, and thus a dedicated ‘Inland Fisheries’ workshop was convened by the South African Society for Aquatic Scientists in June 2018 to update and further develop a list of priority knowledge requirements for inland fisheries in the country. The main themes that emerged during the workshop were developed and contextualised as ten research questions. These were: (1) What is the exploitation potential of inland fisheries? (2) What are the health risks from consuming freshwater fishes? (3) Who currently uses inland fisheries and what are their harvests? (4) What can we learn from historical constraints to inland fisheries development? (5) How will governance of fisheries have to change in an evolving sectoral environment? (6) What are the options for fisheries enhancement? (7) What are the most appropriate fisheries technologies? (8) What value chains and employment opportunities are associated with inland fisheries? (9) What is the impact of water level fluctuations on fish production? (10) What are the impacts of pathogenic diseases on fish populations?

More than 65% of the South African coastline is threatened as a result of pollution, a large proportion of which is land derived. To date the majority of published data on metal monitoring has been on limited regions or once-off sampling events. In this paper, we present the first data on metal exposure at sites along the eastern seaboard of South Africa in resident brown mussels (Perna perna) from six harbour sites (Cape Town, Durban, East London, Mossel Bay, Port Elizabeth and Richards Bay Harbours) over a two-year period (2008 and 2009). These data do not represent historical or the current metal exposure levels, but rather an indication of the degree of metal exposure fluctuations over two years at the same site. Metal accumulation of aluminium, arsenic, cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, lead, selenium, strontium, uranium and zinc was determined by thermo-inductive coupled plasma mass spectrophotometry. The results showed marked fluctuations in metal concentrations between years and identified Cape Town, Mossel Bay and Port Elizabeth Harbours as those sites where mussels had the highest metal levels. Statistically significant variations in metal concentrations were observed between the two sampling periods and the six harbours. Metal concentrations decreased from 2008 to 2009, which was largely attributed to changes in ambient metal concentrations, as a result of variable non-point discharges of metals into the harbours and larger-scale oceanographic changes in upwelling events. The results further emphasise the necessity for annual monitoring of the South African marine environment