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This article discusses a study on the stomach contents of two species of dolphins stranded along the United Arab Emirates coastline. The study aimed to understand the feeding habits of these threatened dolphins by analyzing their stomach contents. The results showed that the dolphins consumed a variety of fish and cephalopods, with some variation between individuals. The study emphasizes the importance of understanding the feeding ecology of these dolphins for their conservation and the overall health of marine ecosystems. Additionally, the study raises concerns about the potential overlap between the dolphins' diet and commercially important fish species in the region. [Extracted from the article]

Abstract--This study documents validation of vertebral band-pair formation in spotted gully shark (Triakis megalopterus) with the use of fluorochrome injection and tagging of captive and wild sharks over a 21-year [...]

Abstract: A Cormack-Jolly-Seber model was developed to estimate abundance, survival, and probability of capture for juvenile (1.8 m TL) raggedtooth sharks (Carcharias taurus) along the east coast of South Africa. [...]

A mass spawning of squid resembles, at first glance, a chaotic 'nuptial dance' (1). But for the first time, we have applied 3-D, radio-linked acoustic positioning (RAP) to this confusing process, and our early results now reveal a choreography that is, in fact, well organized in time and space. Remote tracking with RAP of individual Loligo vulgaris reynaudii off South Africa has provided insights into the daily sequence of behaviors that lead these animals to aggregate for sexual selection. Each dawn, the squid navigate for several kilometers, toward the shore, to small, well-defined zones near egg beds on the substrate. After several hours of circling above these egg beds, a pelagic, 3-D lek-like aggregation of large males forms; females are drawn in, and the aggregation condenses as the females and males pair, mate, and lay eggs. Smaller 'sneaker males' remain on the periphery of the mating arena and, from this station, attempt extra-pair copulations (EPCs). The mating system of squids is thus unexpectedly complex, rivaling those of mammals and birds (2, 3). Commercial squid-jigging fishermen in South Africa have recently been attracted to the spawning grounds, and they have been successful. Moreover, their activities may be selective for large males. Thus, attention should be devoted to ensuring that such targeted fishing does not alter the characteristics of squid population genetics. Remote tracking and video observations, in combination with genetic analyses, may offer a new opportunity to monitor mating effort and reproductive success, and thus to manage the fishery., Determining the reproductive behavior of highly mobile marine animals is challenging, but the results can be rewarding, particularly in situations in which the species is the target of a fishery [...]

Mustelus mustelus from the Langebaan Marine Protected Area (LMPA) has been largely protected from fishing activities for the past 30 years; therefore, its biology represents those of an unfished stock. The reproductive biology, diet, growth and maturity of M. mustelus was studied in the Langebaan Lagoon region in the south-western Cape Coast of South Africa between 2007 and 2009. In total, 217 sharks (females: 381-1734 mm total length (TL); males: 467-1267 mm TL) were examined. Sharks in the Bay represented the largest specimens among six regions, globally. Female parturition, ovulating and mating occurred between November and December after a gestation period of 10-11 months. No ontogenetic shift in diet was evident, with the diet predominantly consisting of the following three species of crustaceans; Hymenosoma orbiculare, Upogebia africana and Callichirus kraussi. The von Bertalanffy growth parameters for combined sexes were L∞ = 1594 mm TL, k = 0.15 year-1, t0 = -2.01 year (n = 95). Possible age over-estimation was investigated using micro-computed tomography, which highlighted the existence of false check marks. This study indicated that the LMPA represents a pupping, nursery and feeding ground as well as a refuge area for the largest and oldest recorded smoothhound sharks globally, emphasising its importance in spatial conservation of this species. [ABSTRACT FROM AUTHOR]

The life history of Risso's dolphins (Grampus griseus) remains poorly known and data from strandings can help provide important information. Data from 126 Risso's dolphins stranded or bycaught along the southeastern coastline of South Africa between 1958 and 2017 were analyzed in relation to their sex, age structure, and diet. Mean estimated length at birth was 146.9 cm, while maximum length was 325 cm for males and 313 cm for females; small sample sizes precluded detailed examination of sexual dimorphism. Age estimates for 33 individuals (14 males, 17 females, 2 unknown sex) indicated a maximum age of 13 years (males) and 17 years (females), respectively; the oldest animal was 19 years (unknown sex). Mean length and age at attainment of sexual maturity were estimated at 280 cm and 7.1 years in males and at 282 cm and 7.7 years in females. Stomach contents from 27 individuals showed that diets of immature and mature males and females overlapped and consisted predominantly of cephalopods. Reported strandings decreased between 2000 and 2017, possibly due to a lack of reporting associated with a ban on driving on beaches or related to the collapse of the local "chokka" squid (Loligo reynaudii) fishery in 2014–2015. [ABSTRACT FROM AUTHOR]

The seasonal occurrence of white sharks visiting Gansbaai, South Africa was investigated from 2007 to 2011 using sightings from white shark cage diving boats. Generalized linear models were used to investigate the number of great white sharks sighted per trip in relation to sex, month, sea surface temperature and Multivariate El Niño/Southern Oscillation (ENSO) Indices (MEI). Water conditions are more variable in summer than winter due to wind-driven cold water upwelling and thermocline displacement, culminating in colder water temperatures, and shark sightings of both sexes were higher during the autumn and winter months (March–August). MEI, an index to quantify the strength of Southern Oscillation, differed in its effect on the recorded numbers of male and female white sharks, with highly significant interannual trends. This data suggests that water temperature and climatic phenomena influence the abundance of white sharks at this coastal site. In this study, more females were seen in Gansbaai overall in warmer water/positive MEI years. Conversely, the opposite trend was observed for males. In cool water years (2010 to 2011) sightings of male sharks were significantly higher than in previous years. The influence of environmental factors on the physiology of sharks in terms of their size and sex is discussed. The findings of this study could contribute to bather safety programmes because the incorporation of environmental parameters into predictive models may help identify times and localities of higher risk to bathers and help mitigate human-white shark interactions. [ABSTRACT FROM AUTHOR]

The deep demersal fish fauna at depths of 100–400 m in canyons off the St Lucia Marine Protected Area along the north coast of KwaZulu-Natal is compared with similar fish communities at the Comoro Islands and in the Indo-Pacific region. Fifty-four fish species were seen or photographed from the submersible Jago or by the discovery team of scuba divers in the coelacanth, Latimeria chalumnae, habitat of the canyons off Sodwana Bay. An additional 94 fish species known from depths of 100–200 m along the coast of northern KwaZulu-Natal are likely to occur in the canyon habitat. The fish fauna of the Sodwana canyons shares at least 18 species with the deep demersal fish community off tropical coral reefs of the Indo-Pacific region. Thirty-seven of the Sodwana canyon fishes are also known from the coelacanth habitat in the Comoros. [ABSTRACT FROM AUTHOR]

Underwater observations of the coelacanth, Latimeria chalumnae Smith, 1939, from a research submersible provided opportunities to study the deep demersal fish fauna at the Comoro Islands. The demersal habitat in depths of 150–400 m at the volcanic island of Ngazidja is low in fish diversity and biomass, compared with the shallow-water coral reef habitat of Ngazidja or the deep demersal habitats of other localities in the Indo-Pacific region. The resident deep demersal fish fauna at Ngazidja is dominated by the coelacanth, an ancient predator that is specially adapted for this low-energy environment. Other large fish predators are scarce in this environment, because of the heavy fishing pressure from local fishermen. Eighty-nine fish taxa (including 65 recognizable species) were recorded from videotapes, photographs, visual observations, fishermen's catches and ancillary attempts to sample the fish fauna with baited fish traps, gill nets, and hook and line. Although no coelacanth feeding events were seen, seven fish species are known from coelacanth stomach contents, and 64 other fish species in this habitat are considered potential prey of this dominant predator. [ABSTRACT FROM AUTHOR]