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The movement and growth of spotted gully sharks Triakis megalopterus (family Triakidae) along the coast of South Africa were investigated using external dart tagging. Of a total of 7 211 sharks tagged, 657 (9.1%) were recaptured over a 37-year period, from 1984 to 2021. Average distance moved by recaptured sharks was 31 (SD 82) km, with a maximum distance moved of 911 km. The longest time at liberty was 6 332 days (17.3 years). Most recaptures (66.9%) displayed resident, philopatric behaviour, although adults moved significantly more than juveniles. There was strong seasonality in the catches, with more individuals caught during summer months (October–March); however, there was no evidence to suggest that adults undertook seasonal migrations to and from mating or pupping areas. Similarly, the findings suggested that pupping likely takes place throughout their distribution and is not confined to a particular region. Growth of recaptured individuals was slow, with an average growth rate of 50 mm year−1. This was similar to the growth rate determined by vertebral band counts but suggested that individuals could reach a theoretical maximum age of 41 years. Based on the species' resident behaviour and slow growth rate, we advocate for maintenance of the current fishing regulations and greater protection in no-take marine protected areas with suitable habitat within their distribution. Further research using acoustic telemetry is also recommended. [ABSTRACT FROM AUTHOR]

The African blackspot shark Carcharhinus humani (until now commonly known as Human's whaler shark) is a small-sized requiem shark (family Carcharhinidae) found in tropical coastal waters of the western Indian Ocean as far south as Port St Johns on the east coast of South Africa. It was only recently recognised as being distinct from the blackspot shark C. sealei, which occurs elsewhere in the Indo-Pacific. This study utilised four datasets to investigate the movements, temporal and geographic distributions, life history and population status of this species in South African waters. The recapture of eight individuals of 294 that were tagged by shore anglers revealed an average distance moved of 33 km (range 1–192 km). Competitive shore anglers caught an average of 39 C. humani per annum along the entire KwaZulu-Natal (KZN) coast, with no marked trend in catch rate over time. Catches in the KZN bather protection programme were extremely low but included 30 pregnant females which displayed a highly seasonal pattern of embryo development. Sightings of C. humani on stereo baited remote underwater video systems (stereo-BRUVS) in the iSimangaliso Marine Protected Area were dominated by females (7.7:1) and were mostly in deeper water of 26–35 m. In all datasets most of the individuals were mature and were present year-round, but with a clear peak in summer and autumn, especially in the catches taken by shore anglers. Competitive shore-angling catch data were used to conduct a risk assessment for the South African population, and, based on values of probability of encounter, the sampled population satisfies the IUCN Red List criteria for Least Concern. [ABSTRACT FROM AUTHOR]

A tag-recapture study was undertaken on the Natal seacatfish Galeichthys troworum in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 473 fish were tagged over a period of 8 years, and 136 individuals (28.8%) were recaptured over a period of 16 years, some of them on multiple occasions. Most recaptures (82%) were caught within 200 m of their release site, with movements ranging between 0 and 617 m, and time-at-liberty ranging between 0 and 3 407 days (9.3 years). Data analysis showed that all recaptured fish remained in relatively small home ranges (of ∼360 m linear distance) and none of them abandoned their home range and moved out of the 2-km2 sampling blocks. While the no-take area of the PMPA provided effective protection for these fish, their relative abundance was similar in an adjacent exploited area. This is likely because G. troworum is not a desired linefish species, with most individuals caught being released, coupled with high post-release survival. [ABSTRACT FROM AUTHOR]

A tag-recapture study was undertaken on Polysteganus praeorbitalis in the Pondoland Marine Protected Area (PMPA) on the east coast of South Africa. A total of 1 042 fish were tagged over a period of 16 years and 255 individuals (24.5%) were recaptured, some of them on multiple occasions. Data analysis showed that 84.7% of recaptured fish remained in relatively small home ranges (-750 m linear distance), while 13.3% abandoned their home ranges and undertook unidirectional movements (of 21-1 211 km) along the KwaZulu-Natal coast in a north-easterly direction, most likely to spawn. While the no-take area of the PMPA provides effective protection for resident fish, the export of adult P. praearbitalis provides strong evidence of the benefits that no-take MPAs can offer to adjacent fisheries. Based on the tag-recapture length data, the growth rate was found to be relatively slow, averaging 46 mm y-1. This growth rate was similar to that determined by a study of ageing using sectioned otoliths. Reliable tag-recapture data can thus be used to provide a valuable means of validating growth rates determined by other methods. [ABSTRACT FROM AUTHOR]

Scientific output has proven the value of the Oceanographic Research Institute's Cooperative Fish Tagging Project (ORI-CFTP) to biological and fisheries research, with more than 95 published manuscripts based on data from the ORI-CFTP. This study reviews the project from the perspective of participating anglers. A total of 267 members of the ORI-CFTP responded to an online survey designed to gather data on the profile of tagging members, their preferred methods of communication, attitudes towards fish tagging and fish conservation in general, changes in angling behaviour since becoming a member of the project, and support for the continuation of the ORI-CFTP. The results reveal that the ORI-CFTP has indeed made a considerable contribution towards improving the conservation ethics and behaviour of marine recreational anglers in South Africa. Improved communication with anglers— both taggers and non-taggers—through the ORI-CFTP has the potential to amplify much-needed conservation information to the broader angling community and thereby enhance environmental awareness. Recommendations on how to improve the ORI-CFTP and other angling-related citizen science projects are provided. [ABSTRACT FROM AUTHOR]

The diamond ray Gymnura natalensis is endemic to southern Africa where its preference for shallow coastal habitats makes it vulnerable to recreational shore-based angling. Although it makes up approximately 1% of the shore-based tag numbers, little is known about its movements, reproduction or population status in South Africa. This study used three independent long-term (34–41 years) datasets, including tagging by recreational anglers, competitive shore angling catches and shark net catches, to investigate the species' movements, catch composition and population status in South Africa. Of the 3 739 individuals tagged (1984–2018), only 30 (1%) were recaptured after an average of 487 days at liberty. The majority (60%) of the recaptures occurred within 10 km of the release site, while 7% had moved more than 1 000 km along the coast. The longest recorded movements (1 577 and 1 756 km) were undertaken by adult rays tagged in the Western Cape Province moving to KwaZulu-Natal Province (KZN). The competitive shore angling catch (1977–2018; n = 9 150) from KZN was dominated by adult rays caught north of Durban, while the shark net catch in KZN (1981–2018; n = 584) was dominated by juvenile rays primarily from the central beaches of Durban. All the datasets exhibited strong seasonal trends with most catches taking place in summer. A risk assessment confirmed a stable to increasing population trend over four generations, suggesting that the population sampled along the east coast of South Africa should be classified as Least Concern. [ABSTRACT FROM AUTHOR]

Information on the movement ecology of endangered species is critical for the implementation of effective conservation measures. This study made use of a long-term dart tagging dataset to reveal the movement patterns and growth rates of two size classes of the Critically Endangered whitespotted wedgefish Rhynchobatus djiddensis within its southern African distribution, which can have important implications for fisheries management. A total of 4 768 individuals were tagged with 340 recaptures recorded, ranging from 1 to 2 639 days (7.2 years) at liberty. Most of the tag releases and recaptures occurred within the KwaZulu-Natal central region in South Africa, with catches increasing significantly during summer (October to March). Most recaptures (43%) were recorded within 5 km of the tagging (release) site. Tagged adults recorded significantly greater distances moved than juveniles (p < 0.002) but there was no significant difference between juveniles or adults in terms of their direction of movement (p > 0.30). A Francis growth model showed that smaller individuals had a substantially faster growth rate (198.69 [SE 21.75] mm year−1) compared with larger individuals (57.41 [SE 27.83] mm year−1) confirming that the species is relatively slow-growing. Ultimately, this study identified important knowledge gaps in the broadscale movement patterns of R. djiddensis and provided new information on the growth rate of this Critically Endangered species. Filling in these knowledge gaps will aid in conservation measures for two important size classes of the R. djiddensis population as the species faces increasing targeted fishing pressure. [ABSTRACT FROM AUTHOR]