Novel approach to studying marine fauna: using long-life remote underwater video cameras to assess occurrence and behaviour of threatened and data-deficient elasmobranch species in southern Mozambique DOI Creative Commons
Johanna Buschmann,

Kim G. Roques,

Jaime S. Davies

et al.

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Dec. 23, 2024

Understanding the behaviour and ecological role of elasmobranchs is essential for their conservation, particularly in regions harbouring threatened data-deficient species like Inhambane coastline southern Mozambique, southwestern Indian Ocean. This study employed long-life remote underwater video cameras (LL-RUV) to observe elasmobranch occurrence at a rocky reef near Praia do Tofo known frequent sightings. Between 2021 2024, 524 hours LL-RUV data were collected, revealing presence 14 species. Reef manta rays ( Mobula alfredi ), small eye stingrays Megatrygon microps oceanic birostris ) identified as primary users studied cleaning stations (n = 81, n 72 61 respectively), engaging mutualistic interactions with cleaner fish spending significant amounts time reef. In contrast, spotted eagle Aetobatus narinari blacktip sharks Carcharhinus limbatus solely observed cruising over without 40 27 respectively). addition, this provides evidence intra- inter-specific between rays, bowmouth guitarfish Rhina ancylostoma co-occurrences both ray smalleye “hitchhiker” including cobia Rachycentron canadum remoras Echeneis spp.). The use represents advancement marine research. These enable continuous, non-intrusive, long-term monitoring environments, capturing natural behaviours, while minimising disturbances caused by divers. As result, more accurate observations station dynamics can be recorded, which might missed during short-term surveys. research highlights potential powerful tools advancing our understanding underscores value informing targeted effective conservation strategies. Beyond research, LL-RUVs hold tremendous studying wide range habitats, offering versatile tool efforts across diverse ecosystems.

Language: Английский

Multi-decade catches of manta rays (Mobula alfredi, M. birostris) from South Africa reveal significant decline DOI Creative Commons
Michelle Carpenter, D. Stott Parker, Matthew L. Dicken

et al.

Frontiers in Marine Science, Journal Year: 2023, Volume and Issue: 10

Published: March 29, 2023

Manta rays ( Mobula alfredi and M. birostris ) are poorly understood in South Africa, despite their ecological importance charismatic appeal. This study analyzed a 41-year dataset from the KwaZulu-Natal bather protection program to investigate catch per unit effort between 1981-2021. We used Generalized Additive Models probability of encounter assess annual seasonal trends, as well effect location moon phases on rates. also evaluated size composition demographics caught manta using same dataset. Our analysis revealed significant decline overall ray catches since late 1990s (p<0.0001), with increased rates during summer, suggesting visitation African waters. found that were at least once all 46 netted beaches along 350 km span coastline, but significantly more Central Area, Anstey’s beach north Mtwalume south. observed phase had an presence, spring tides new full phases. Over half individuals juveniles, total 841 (52% catch) belonged confirmed juvenile class (1400-2500 mm disc width). further greater proportion (70%) juveniles southernmost sampled area, Hibberdene Mzamba These findings highlight waters habitat for southern coastline. The spatial-temporal patterns we have critical implications management conservation efforts. provides valuable baseline data future research underscores need continued monitoring these iconic marine species.

Language: Английский

Citations

10
Persistent declines in sightings of manta and devil rays (Mobulidae) at a global hotspot in southern Mozambique DOI Creative Commons
Stephanie K. Venables, Christoph A. Rohner, Anna L. Flam

et al.

Environmental Biology of Fishes, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 5, 2024

Language: Английский

Citations

3
Preliminary insights into manta ray (Mobula alfredi and M. birostris) population demographics and distribution in South Africa DOI Creative Commons
Morgan Carpenter, Nakia Cullain, Ryan Daly

et al.

Environmental Biology of Fishes, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Abstract Both the reef manta ray, Mobula alfredi and oceanic ray M. birostris , are repeatedly observed in South Africa, yet little is known about distributions of either species. In this study, we collated citizen science observations since 2003 to reveal six areas KwaZulu-Natal (KZN) Eastern Cape provinces, where rays have been sighted across multiple years. Using their unique ventral spot patterning, 184 individuals were photo-identified, comprising 139 45 . Most photo-identified encountered iSimangaliso Wetland Park (IWP) KZN (89%; n = 119) for Aliwal Shoal (48%; 22). We identified 32 new transboundary records 28 also photographed Inhambane Province, Mozambique, demonstrating connectivity, specifically Závora ( 27). One individual traveled times between IWP Závora, totaling 1305 km, another from Pondoland MPA a distance over 600 km. Further, extend southern range Africa by 500 km Mdumbi Beach Port Ngqura, Cape. These collective findings represent Africa’s first in-water assessment aggregations, showing particular be critical habitat movements documented here suggest population one most mobile globally. hope baseline data provided will drive increased research management along coastlines.

Language: Английский

Citations

0
Estimating the abundance and population trends of reef manta rays (Mobula alfredi) in Nusa Penida, Bali, Indonesia DOI

Janis Argeswara,

Stephanie K. Venables, Elitza S. Germanov

et al.

Environmental Biology of Fishes, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

Language: Английский

Citations

0
Movements and habitat use of reef manta rays around the Mozambique Channel Island of Mayotte, Southwestern Indian Ocean DOI
Christoph A. Rohner, Stephanie K. Venables, Anna M. Knochel

et al.

Environmental Biology of Fishes, Journal Year: 2025, Volume and Issue: unknown

Published: April 29, 2025

Language: Английский

Citations

0
Persistent transboundary movements of threatened sharks highlight the importance of cooperative management for effective conservation DOI
Ryan Daly, Stephanie K. Venables,

TD Rogers

et al.

Marine Ecology Progress Series, Journal Year: 2023, Volume and Issue: 720, P. 117 - 131

Published: Sept. 4, 2023

Migratory sharks play a key ecological role through movements within and among marine ecosystems, yet many populations are declining. Addressing the decline is especially challenging for wide-ranging species, as they may undertake between countries with disparate conservation priorities. To investigate transboundary migrations of threatened neighbouring South Africa Mozambique, we tracked 4 commonly occurring carcharhinid species (bull, blacktip, tiger grey reef sharks). A total 102 individuals were fitted long-life acoustic transmitters monitored yr (2018-2022) on an receiver network 350 receivers. During this period, 63% tagged bull (n = 19), 87% blacktips 13), 94% 16) 25% 3) undertook movements. The frequency mean per year ranged 1.3 ± 1.5 (SD) 81 35.6 sharks. Blacktip, all long-distance ranging from 980 to 2256 km. These data confirm high connectivity by undertaking persistent This study emphasizes need collaborative cooperation 2 alignment regional management plans interventions address declining shark in region Western Indian Ocean.

Language: Английский

Citations

7
Size at sexual maturity, seasonal variation by maturity stages, and fecundity of the spotted round ray (Urobatis maculatus) and the thorny stingray (Urotrygon rogersi) from the northern tropical eastern Pacific DOI Creative Commons
Alain García‐Rodríguez, Javier Tovar‐Ávila,

A. Hiromi Arellano‐Cuenca

et al.

Journal of Fish Biology, Journal Year: 2024, Volume and Issue: 104(5), P. 1587 - 1602

Published: Feb. 28, 2024

Abstract Round rays (family: Urotrygonidae) are commonly caught as by‐catch by shrimp trawl fisheries in the tropical eastern Pacific (TEP). However, little information on their life history and catch species composition exists for most round ray species, preventing evaluation of impact fishing populations. The mean size at sexual maturity ( DW 50 ), seasonal variation stages, fecundity two during research cruises south‐eastern Gulf California (northern TEP) were estimated using a multi‐model approach inference first time, to determine part population each that is being affected trawling. Disc width ) ranged from 7.0 30.9 cm spotted Urobatis maculatus 7.2–33.5 thorny stingray Urotrygon rogersi with females reaching larger sizes than males both species. was 12.8 11.8 U. , respectively, whereas U.rogersi it 15.0 18.4 females, respectively. Embryos found ≥14.5 maximum five embryos (mean = 3.1 ± 0.2 S.E. mode 4), six 3.0 0.3 2). Fecundity embryo did not vary maternal size. Male female immature mature individuals including pregnant catches all seasons year. Our results can help vulnerability studied populations pressure trawling northern TEP guide development future monitoring strategies conservation actions these if necessary.

Language: Английский

Citations

1
Perceptions regarding the recreational cobia fishery in relation to manta ray conservation DOI
R Blachman Braun, Julia Wester, Catherine Macdonald

et al.

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2024, Volume and Issue: 34(4)

Published: April 1, 2024

Abstract Understanding fisheries requires not only traditional modelling approaches but also the incorporation of local ecological knowledge (LEK) which can provide other types essential contextualizing knowledge. Recreational anglers within cobia fishery on east coast central and northern Florida target by seeking out manta rays often follow associate with, casting at or near them. Results suggest this poses a threat entanglement, injury disturbance to mantas in region, especially associated with practices behaviours inexperienced anglers. Expert angler responses interviews described changes habitat use reductions abundance Experienced pointed social media as key driver expansion an explanation for their perception growing presence novice engaged these practices. Respondents proposed best potential management interventions generally supported conservation action, including through willingness engage researchers support enforcement measures related fishery.

Language: Английский

Citations

1
Killer Whale Predation on a Giant Manta Ray (Mobula birostris), a Sicklefin Devil Ray (Mobula tarapacana) and a Tiger Shark (Galeocerdo cuvier) in the Southwest Indian Ocean DOI Creative Commons
Maeva Terrapon, Stephanie K. Venables,

Anthony Lokker

et al.

African Journal of Ecology, Journal Year: 2024, Volume and Issue: 62(4)

Published: Oct. 29, 2024

ABSTRACT Knowledge of killer whale ( Orcinus orca ) feeding ecology in tropical waters is scarce. In the southwest Indian Ocean, opportunistic sightings provide a valuable source information to better understand their behaviour, diet and distribution. Here, we compile existing records predation on elasmobranchs including three undescribed prey species regionally: giant manta ray Mobula birostris ), sicklefin devil tarapacana tiger shark Galeocerdo cuvier ). Documenting such observations important increase knowledge tropics cascading impact they might have populations.

Language: Английский

Citations

0
Novel approach to studying marine fauna: using long-life remote underwater video cameras to assess occurrence and behaviour of threatened and data-deficient elasmobranch species in southern Mozambique DOI Creative Commons
Johanna Buschmann,

Kim G. Roques,

Jaime S. Davies

et al.

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 11

Published: Dec. 23, 2024

Understanding the behaviour and ecological role of elasmobranchs is essential for their conservation, particularly in regions harbouring threatened data-deficient species like Inhambane coastline southern Mozambique, southwestern Indian Ocean. This study employed long-life remote underwater video cameras (LL-RUV) to observe elasmobranch occurrence at a rocky reef near Praia do Tofo known frequent sightings. Between 2021 2024, 524 hours LL-RUV data were collected, revealing presence 14 species. Reef manta rays ( Mobula alfredi ), small eye stingrays Megatrygon microps oceanic birostris ) identified as primary users studied cleaning stations (n = 81, n 72 61 respectively), engaging mutualistic interactions with cleaner fish spending significant amounts time reef. In contrast, spotted eagle Aetobatus narinari blacktip sharks Carcharhinus limbatus solely observed cruising over without 40 27 respectively). addition, this provides evidence intra- inter-specific between rays, bowmouth guitarfish Rhina ancylostoma co-occurrences both ray smalleye “hitchhiker” including cobia Rachycentron canadum remoras Echeneis spp.). The use represents advancement marine research. These enable continuous, non-intrusive, long-term monitoring environments, capturing natural behaviours, while minimising disturbances caused by divers. As result, more accurate observations station dynamics can be recorded, which might missed during short-term surveys. research highlights potential powerful tools advancing our understanding underscores value informing targeted effective conservation strategies. Beyond research, LL-RUVs hold tremendous studying wide range habitats, offering versatile tool efforts across diverse ecosystems.

Language: Английский

Citations

0