Rhett Hamilton Bennett

Wildlife Conservation Society | WCS · Western Indian Ocean shark and ray conservation program

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO and adjacent waters (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endanger...

In recent decades, a combination of increasing demand and economic globalisation has created a global market for elasmobranch products, especially the highly prized shark fins for Asian markets. Morphological species identification, as well as traditional cytochrome c oxidase subunit I (COI) barcoding of shark fins and other products, become challe...

The southwest Indian Ocean (SWIO) is a hotspot of endemic and evolutionarily distinct sharks and rays. We summarise the extinction risk of the sharks and rays endemic to coastal, shelf, and slope waters of the SWIO and adjacent waters (Namibia to Kenya, including SWIO islands). Thirteen of 70 species (19%) are threatened: one is Critically Endanger...

Red list assessment of Dasyatis chrysonata

The Critically Endangered shorttail nurse shark Pseudoginglymostoma brevicaudatum (Günther, 1866) is a small-bodied Orectolobiform shark found only in the Western Indian Ocean (WIO). We report here on a significant range extension for P. brevicaudatum based on four records of the species in southern Mozambique, recorded during research surveys, inc...

• The white‐spotted wedgefish (Rhynchobatus djiddensis) is a Critically Endangered shark‐like ray in the family Rhinidae. Throughout its Western Indian Ocean distribution, it is targeted for its valuable meat and fins and is reported to have undergone major population declines. However, there remains a need for species specific time‐series data to...

Tourism generated through bonefish (Albula spp.) fishing contributes to the economies of many isolated tropical islands and atolls. However, little research has been conducted on bonefish in the Indian Ocean. This study aimed to contribute to the understanding of bonefish ecology in the Indian Ocean by quantifying the spatial and temporal movements...

The giant trevally Caranx ignobilis (Forsskål) is an important apex predatory fish typically associated with coral reef communities. It is prized in recreational and commercial fisheries, yet little is known about its aggregation dynamics and susceptibility to fishing pressure. This study reports on a previously undocumented aggregation of mature g...

Decreasing populations of common estuary-associated marine fishes are being documented globally and red flags associated with such declines are often ignored due to the high relative abundance of these species when compared to more rare and threatened taxa. The Cape stumpnose Rhabdosargus holubi (Steindachner 1881) is an abundant and widespread sou...

Connectivity — movements of animals between and among numerous habitats — and the factors (rhythmic cycles and environmental variables) influencing connectivity of juvenile Lichia amia (Teleostei: Carangidae) were assessed in complementary acoustic telemetry studies in two geographically separated estuaries (620 km apart) in South Africa. The studi...

Predictable fish aggregations of commercially valuable species are particularly susceptible to overexploitation. Giant trevally Caranx ignobilis are ecologically important top predatory fish targeted in both recreational and commercial fisheries; however, little is known about their aggregation dynamics or susceptibility to overexploitation. This s...

The Acoustic Tracking Array Platform (ATAP) is a marine science programme that monitors the movements and migrations of inshore marine animals along the South African coastline. Acoustically tagged animals are monitored by an expanded network of approximately 100 automated data-logging acoustic receivers moored at strategic node sites, from Cape Po...

Understanding movement behaviour is essential for effective management of fishery species. Dart tags were used to study coastal movement patterns of white steenbras Lithognathus lithognathus, an overexploited seabream (Sparidae) in South Africa. In total, 6 962 fish (190–1 080 mm fork length) were tagged throughout the species’ distributional range...

A total of 21 juvenile Cape stumpnose (Rhabdosargus holubi) were tagged with internal acoustic transmitters in the lower, middle and upper reaches of the Kowie Estuary, South Africa. The movements of all fishes were continually monitored for five months using 22 stationary data-logging acoustic receivers, positioned along the length of the estuary....

Twenty-one juvenile Cape stumpnose Rhabdosargus holubi (140–190 mm fork length) were tagged with internal acoustic transmitters in the lower, middle and upper reaches of the Kowie Estuary, South Africa. The movements of each fish were continually monitored from October 2014 to February 2015 using 22 stationary data-logging acoustic receivers situat...

Understanding the level of connectivity between estuarine and coastal waters is essential for appropriate management of estuarine-associated taxa. Most studies have focused on the role of a single estuary, while limited research exists on the importance of multiple estuaries to individuals of estuarine-associated species. This study used acoustic t...

Understanding and characterising movement and area-use patterns of fishes within estuaries, as well as understanding the degree of connectivity between estuaries and the marine environment, can provide important insights into a species’ ecology, which is fundamental for effective management and conservation. Mark-and-recapture data obtained from th...

White steenbras Lithognathus lithognathus (Teleostei: Sparidae) is an overexploited marine fish species endemic to South Africa. Overexploitation in recreational, subsistence and commercial fisheries has resulted in stock collapse and the need for improved management of the species. Adults are thought to undertake large-scale annual spawning migrat...

Collection of data from animals for research purposes can negatively impact target or by-catch species if suitable animal ethics practices are not followed. This study aimed to assess the ethical requirements of peer-reviewed scientific journals that publish primary literature on fishes, and review the ethical considerations and animal care guideli...

Habitat connectivity is a fundamental component of estuary-associated fish behaviour. Understanding this is critical to understanding population dynamics and the nursery role of estuarine habitats. This study aimed to elucidate the intra-population structure of juvenile Argyrosomus japonicus and the role of estuarine and coastal habitats for this w...

This study provides empirical data on the exploitation of fishery resources on the Sundays Estuary on the south-east coast of South Africa. Total annual effort was estimated at 63 785 angler-hours, which accounted for an annual yield of 16 214 fish (8.0 t). Effort and mean catch per unit effort exhibited seasonal trends and were highest during summ...

Acoustic telemetry and long-term seine-netting data were used to assess distribution, area use, home range dynamics and movement patterns of estuarine-dependent juvenile white steenbras Lithognathus lithognathus in the temporarily open/closed East Kleinemonde Estuary. Using 15 years of biannual seine-netting data, it was shown that white steenbras...

The spatial dynamics and home range sizes of early juvenile white steenbras (Lithognathus lithognathus Cuvier, 1829) in the permanently open Great Fish Estuary, South Africa, were assessed using acoustic telemetry. Seven individuals (154–184 mm fork length) tagged with acoustic transmitters spent the majority of their time in the mesohaline to olig...

Standardised sampling protocols for monitoring fish stocks are essential to assess changes in stock status and provide a means to evaluate the effectiveness of fisheries management measures, such as marine protected areas (MPAs). This study aimed to optimise two standard sampling methods, namely underwater visual census (UVC) and controlled angling...

Marine Protected Areas (MPAs), the Ecosystem Approach to Fisheries management (EAF) and Integrated Coastal Management (ICM) have been identified as possible alternatives to traditional linefish management measures, which have largely failed.Monitoring and assessment of fish communities on a long-term basis is necessary, and will provide a means to...