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Holohalaelurus regani and Scyliorhinus capensis are relatively small catsharks, which both occur off the continental shelf around South Africa and are often caught together as by‐catch in demersal trawls. The present study used data collected during annual demersal research surveys conducted between 2009 and 2015 and is a first attempt at modeling the potential intra‐ and interspecific associations, by maturity stage and depth, of H. regani and S. capensis to elucidate species‐specific patterns in their distributions in South African waters. Intraspecifically, both species displayed a wide overlap in distribution between maturity stages, but only H. regani displayed marked changes in distribution with maturity stage, with mature individuals found further eastwards and occupying deeper waters than immature individuals. Interspecifically, the two catsharks displayed an inverse relationship in their distribution, with an increase in the abundance of H. regani and a decrease in the abundance of S. capensis when moving from the south coast to the west coast. Some localized patches of co‐occurrence were, however, evident between species and maturity stages, especially in offshore areas. Overall, our results indicated a stronger co‐occurrence of mature and immature stages within each species and a rather weak co‐occurrence of maturity stages between the two species. The spatial information provided in the present study provides useful information on how sharks with similar morphologies and lifestyles may partition their habitat as a mechanism for potentially reducing competition between them. [ABSTRACT FROM AUTHOR]

Washed-up chondrichthyan egg cases were collected along three different sandy beaches around Plettenberg Bay, South Africa, between April 2016 and March 2017. GPS location was recorded upon collection, and, after being soaked in fresh water for 12 hours, egg cases were identified to species level. Additionally, boreholes, damage, biofouling and state of the hatchling slit were recorded. The hatching success of each egg case was inferred from these factors. Over the year, 6 996 egg cases of nine species were collected. Egg cases of the tiger catshark Halaelurus natalensis had the highest hatching rate at 70%. Egg cases of the leopard catshark Poroderma pantherinum had the highest predation rate at 57%. Season had no significant effect either on overall egg-case counts or on per-species counts. Location, however, significantly affected the overall egg-case counts, as well as per-species counts, with the exceptions of H. natalensis and the St Joseph Callorhinchus capensis. The results of this study provide insight into chondrichthyan species occurrence and spatial variation along a section of the Garden Route in the Western Cape Province and can act as a baseline for future research. [ABSTRACT FROM AUTHOR]

Despite the high abundance of the gobiid fish Glossogobius callidus in many freshwater ecosystems in South Africa, very few studies have assessed the biology and ecology of the species. Here, we investigated the diet of G. callidus populations sourced from Sundays River irrigation ponds. A total of 571 fish grouped into two size classes (TL, range ± SD: juveniles of 20–60 ± 45 mm; adults of 61–140 ± 85 mm) were sampled by seine netting; prey items were removed from the guts and identified and sorted to obtain dietary information for each prey group. Of the examined guts, 97% contained prey comprising 17 taxa within 10 taxonomic groups. Teleosts were identified to species level, whereas most dietary components were identified to a broad taxonomic group. Aquatic invertebrates were the most important component of the diet of G. callidus, but the index of relative importance (%IRI) of dominant invertebrate taxa varied according to ontogenetic stage of G. callidus and season. Prey taxa included: Diptera, Hemiptera, Trichoptera, Odonata, Cladocera, Copepoda, Hydracarina, Amphipoda, Mollusca and Teleostei. Dipteran prey taxa were consistently encountered in both size classes and across all seasons. G. callidus can therefore be regarded as a generalist invertivore. [ABSTRACT FROM AUTHOR]