scholarly journals Effects of a COVID‐19 lockdown‐induced pause and resumption of artificial provisioning on blacktip reef sharks ( Carcharhinus melanopterus ) and pink whiprays ( Pateobatis fai ) in French Polynesia (East‐Pacific)

Ethology ◽  
2021 ◽  
Author(s):  
Clémentine Séguigne ◽  
Johann Mourier ◽  
Thomas Vignaud ◽  
Nicolas Buray ◽  
Éric Clua
Keyword(s):  
French Polynesia ◽  
East Pacific ◽  
Reef Sharks ◽  
Carcharhinus Melanopterus

scholarly journals Same species, different prerequisites: investigating body condition and foraging success in young reef sharks between an atoll and an island system

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ornella C. Weideli ◽  
Ian A. Bouyoucos ◽  
Yannis P. Papastamatiou ◽  
Gauthier Mescam ◽  
Jodie L. Rummer ◽  
...  
Keyword(s):  
Body Condition ◽  
Prey Availability ◽  
Management Strategies ◽  
Maternal Investment ◽  
French Polynesia ◽  
Foraging Success ◽  
Site Specific ◽  
Reef Sharks ◽  
Island System ◽  
Carcharhinus Melanopterus

Abstract Acquiring and storing energy is vital to sharks of all age-classes. Viviparous shark embryos receive endogenous maternal energy reserves to sustain the first weeks after birth. Then, in order to maintain body condition, sharks must start foraging. Our goal was to understand whether maternal energy investments vary between blacktip reef sharks (Carcharhinus melanopterus) from two populations and to what extent body condition and the initiation of foraging might be affected by presumably variable maternal investments. A total of 546 young sharks were captured at St. Joseph atoll (Seychelles) and Moorea (French Polynesia) between 2014 and 2018, and indices of body condition and percentage of stomachs containing prey were measured. Maternal investment was found to be site-specific, with significantly larger, heavier, and better conditioned individuals in Moorea. Despite these advantages, as time progressed, Moorea sharks exhibited significant decreases in body condition and were slower to initiate foraging. We suggest that the young sharks’ foraging success is independent of the quality of maternal energy resources, and that other factors, such as prey availability, prey quality, and/or anthropogenic stressors are likely responsible for the observed differences across sites. Insights into intraspecific variations in early life-stages may further support site-specific management strategies for young sharks from nearshore habitats.

scholarly journals Relationship between the biomass of reef shark and fish in South Morotai Waters, North Maluku, Indonesia

2020 ◽  
Vol 21 (12) ◽  
Author(s):  
JIBRIEL FIRMAN SOFYAN ◽  
AMBARIYANTO AMBARIYANTO ◽  
KEN SUWARTIMAH ◽  
Abdul Hamid A. Toha
Keyword(s):  
Regression Analysis ◽  
Positive Relationship ◽  
Biomass Estimation ◽  
Functional Composition ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Reef Shark ◽  
Triaenodon Obesus ◽  
Reef Sharks ◽  
Carcharhinus Melanopterus

Abstract. Sofyan JF, Ambariyanto A, Suwartimah K, Toha AHA. 2020. Relationship between the biomass of reef shark and fish in South Morotai Waters, North Maluku, Indonesia. Biodiversitas 21: 5605-5613. This study aims to determine the biomass of reef shark and fish in South Morotai Waters in North Maluku, Indonesia. The Audible Stationary Count and Underwater Visual Census method were used to collect the data of reef sharks and fish. Seven and one site locations of coral reef and shark ecosystems were surveyed and, the data were analyzed using regression analysis to obtain a correlation between the variables. The three reef sharks found were Carcharhinus melanopterus, Triaenodon obesus, and Carcharhinus amblyrhynchos. Biomass estimation of reef sharks and fish ranged from 0.59 to 19.97 kg/ha and 30.95 kg/ha to 49.92 kg/ha, consisting of 8 families. In the area of aggregations, both species were found in 7 sites, and the population of reef shark amounted to 86.96 kg/ha and fish was around 55.705 kg/ha, consisting of 9 families. There was a positive relationship between the biomass of reef shark and fish in South Morotai waters, and the index of determination was 0.8043, showing that the biomass of reef shark was influenced by that of fish. These results indicated the importance of biomass in determining the functional composition and diversity of reef shark and fish.

scholarly journals Home range of newborn blacktip reef sharks (Carcharhinus melanopterus), as estimated using mark-recapture and acoustic telemetry

Coral Reefs ◽  
2020 ◽  
Vol 39 (5) ◽  
pp. 1209-1214 ◽  
Author(s):  
Ian A. Bouyoucos ◽  
Martin Romain ◽  
Lorine Azoulai ◽  
Kim Eustache ◽  
Johann Mourier ◽  
...  
Keyword(s):  
Home Range ◽  
Acoustic Telemetry ◽  
Mark Recapture ◽  
Reef Sharks ◽  
Carcharhinus Melanopterus

scholarly journals Response of blacktip reef sharks Carcharhinus melanopterus to shark bite mitigation products

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Madeline Thiele ◽  
Johann Mourier ◽  
Yannis Papastamatiou ◽  
Laurent Ballesta ◽  
Eric Chateauminois ◽  
...  
Keyword(s):  
Reef Sharks ◽  
Carcharhinus Melanopterus

Physiological response and immediate mortality of gill-net-caught blacktip reef sharks (Carcharhinus melanopterus)

2017 ◽  
Vol 68 (9) ◽  
pp. 1734 ◽  
Author(s):  
Derek R. Dapp ◽  
Charlie Huveneers ◽  
Terence I. Walker ◽  
Richard D. Reina
Keyword(s):  
Conservation Status ◽  
Management Strategies ◽  
Population Monitoring ◽  
Mortality Rates ◽  
Plasma Lactate ◽  
Elevated Plasma ◽  
Gill Net ◽  
Reef Sharks ◽  
Carcharhinus Melanopterus ◽  
Related Mortality

To investigate factors contributing to immediate mortality in gill-net-caught elasmobranchs, we caught and blood sampled a total of 64 sharks and rays. Blacktip reef sharks (Carcharhinus melanopterus) were the most commonly caught species and had significantly elevated plasma lactate (mean 23.3 mM) and potassium (mean 6.2 mM) concentrations following capture, suggesting physiological disturbance. The overall immediate mortality rate of C. melanopterus was 38% and mortality was significantly influenced by body size, but not location of entanglement or sex. Of the other species caught, nervous sharks (Carcharhinus cautus) were of particular concern, because this species is often caught as bycatch by gill-net fisheries throughout its range and experienced high immediate mortality rates when captured (66%; n = 12) in the present study. The results suggest that juvenile C. melanopterus are particularly susceptible to gill-net-related mortality and that fisheries management strategies for C. melanopterus bycatch should focus on reducing the likelihood of juvenile sharks encountering this gear. Given that this species is not currently considered to be threatened with extinction, population monitoring should be performed such that the suggested regulations can be implemented if populations decline to levels threatening the conservation status of the species.

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