Life after death: behaviour of multiple shark species scavenging a whale carcass

2019 ◽  
Vol 70 (2) ◽  
pp. 302 ◽  
Author(s):  
J. S. E. Lea ◽  
R. Daly ◽  
C. Leon ◽  
C. A. K. Daly ◽  
C. R. Clarke
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Sperm Whale ◽  
Shark Species ◽  
Tiger Shark ◽  
Nurse Shark ◽  
Life After Death ◽  
Galeocerdo Cuvier ◽  
Carcharhinus Leucas ◽  
Bull Shark

A drone was used to study the richness and behaviour of scavengers attracted to the carcass of a sperm whale (Physeter microcephalus) in Seychelles, Western Indian Ocean. Over 30 sharks of 3 species (tiger shark Galeocerdo cuvier, bull shark Carcharhinus leucas and tawny nurse shark Nebrius ferrugineus) were recorded scavenging on the carcass. Tiger sharks dominated the scavenging, but with no evidence of agonistic behaviours or hierarchy, and may have facilitated scavenging by other species. Drone use allowed the analysis of such behaviours without observer influence, providing new insights into communal scavenging events.

scholarly journals New records of sharks (Elasmobranchii) from the Andaman and Nicobar Archipelago in India with notes on current checklists

2018 ◽  
Vol 6 ◽  
Author(s):  
Zoya Tyabji ◽  
Rima Jabado ◽  
Dipani Sutaria
Keyword(s):  
Geographical Location ◽  
Shark Species ◽  
Tiger Shark ◽  
Limited Information ◽  
Nurse Shark ◽  
Important Species ◽  
Inaccurate Information ◽  
Management Measures ◽  
Bull Shark ◽  
Over Exploitation

The diversity of sharks occurring off the Andaman and Nicobar Archipelago in India has received increased attention in recent years. Yet, available checklists are out of date, often with inaccurate information and a number of commercially important species have not been documented through research and fish landing surveys. Here we report on shark species examined during fish landing surveys conducted from January 2017 to March 2018. Records of twelve previously unreported species from the archipelago are presented and include the bignose shark (Carcharhinusaltimus), pigeye shark (Carcharhinusamboinensis), bull shark (Carcharhinusleucas), snaggletooth shark (Hemipristiselongata), slender weasel shark (Paragaleusrandalli), Arabian smoothhound shark (Mustelusmosis), Indonesian houndshark (Hemitriakisindroyonoi), sand tiger shark (Carchariastaurus), Indonesian bambooshark (Chiloscylliumhasseltii), tawny nurse shark (Nebriusferrugineus), dwarf gulper shark (Centrophorusatromarginatus), and the Indonesian shortsnout spurdog (Squalushemipinnis). These records increase the reported shark species for the archipelago from 47 to 59 and for India from 114 to 116. Additionally, a size extension in the total length ofC.hasseltiiby 27 cm and ofP.randalliby 8 cm is reported. Owing to the bio-geographical location of these islands, species diversity around the archipelago is unique and appears to overlap with that of southeast Asia. With increasing reports of over-exploitation and the operation of a targeted shark fishery by distant water fleets in these waters, the limited information on shark diversity from this region is of concern. Systematic and long-term monitoring of catches, combined with accurate species identification, is crucial to provide information on management measures.

scholarly journals Diet of the bull shark, Carcharhinus leucas, and the tiger shark,Galeocerdo cuvier, in the eastern Pacific Ocean

2017 ◽  
Vol 41 ◽  
pp. 1111-1117 ◽  
Author(s):  
Colombo ESTUPIÑÁN-MONTAÑO ◽  
José Félix ESTUPIÑÁN-ORTIZ ◽  
Luis Germán CEDEÑO-FIGUEROA ◽  
Felipe GALVÁN-MAGAÑA ◽  
Carlos Julio POLO-SILVA
Keyword(s):  
Pacific Ocean ◽  
Eastern Pacific ◽  
Tiger Shark ◽  
Eastern Pacific Ocean ◽  
Galeocerdo Cuvier ◽  
Carcharhinus Leucas ◽  
Bull Shark

New insights into the reproductive biology of the tiger shark Galeocerdo cuvier and no detection of polyandry in Reunion Island, western Indian Ocean

2020 ◽  
Vol 71 (10) ◽  
pp. 1301 ◽  
Author(s):  
Agathe Pirog ◽  
Hélène Magalon ◽  
Thomas Poirout ◽  
Sébastien Jaquemet
Keyword(s):  
Indian Ocean ◽  
Reproductive Biology ◽  
Population Biology ◽  
Western Indian Ocean ◽  
Analysis Of Covariance ◽  
Tiger Shark ◽  
Reunion Island ◽  
Frequency Distributions ◽  
Galeocerdo Cuvier ◽  
Réunion Island

The reproductive biology of the tiger shark Galeocerdo cuvier remains poorly documented because it is difficult to obtain data on a sufficient number of mature individuals to conduct appropriate analyses and thus to adequately investigate its population biology. In this study, the reproductive traits of 150 individuals caught during a shark control program in Reunion Island (western Indian Ocean), including five gravid females, were investigated. Specific microsatellite loci were used to investigate the occurrence of polyandry. The total length (TL) of the studied individuals was 130–415cm for males and 175–429cm for females. Sizes at maturity were estimated at 278.5cm for males and 336cm for females. Although the length–weight relationships differed between both sexes (analysis of covariance (ANCOVA): intercept, n=49, F1,45=0.95, P=0.34; slope, n=49, F1,45=8.39, P=0.01), the TL–frequency distributions did not differ significantly. Parturition likely occurs during the warm season, in December–January. No evidence of genetic polyandry was detected, and this supports recently published results. This absence of polyandry in the species likely reflects both a long reproductive cycle and a specific reproductive behaviour related to the oceanic nature of the tiger shark. These results are valuable for improving conservation and management plans for this species.

scholarly journals Feeding patterns of two sympatric shark predators in coastal ecosystems of an oceanic island

2017 ◽  
Vol 74 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Clément Trystram ◽  
Karyne M. Rogers ◽  
Marc Soria ◽  
Sébastien Jaquemet
Keyword(s):  
Trophic Ecology ◽  
Dietary Habits ◽  
Stomach Contents ◽  
Nitrogen Isotope ◽  
Oceanic Island ◽  
Apex Predators ◽  
Coastal Habitat ◽  
Galeocerdo Cuvier ◽  
Carcharhinus Leucas ◽  
Bull Shark

Stomach contents and stable carbon and nitrogen isotope analyses (δ13C and δ15N) were used to investigate the trophic ecology of two apex predators, tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas), from Reunion Island to describe their dietary habits at both the population and individual levels. In this oceanic island, the tiger and bull sharks were more piscivorous and teutophagous than noted in previous research from other localities. The δ13C values suggested that bull sharks depended on more neritic organic matter sources than tiger sharks, confirming a coastal habitat preference for bull sharks. Moreover, the total length of the bull shark influenced δ13C values, with smaller individuals being more coastal than larger individuals. All indicators suggest that there is a higher degree of similarity between individual tiger sharks compared with the more heterogeneous bull shark population, which is composed of individuals who specialize on different prey. These results suggest that the two species have different functions in these coastal habitats, and thus, they must be considered independently in terms of conservation and management.

scholarly journals First evidence of multiple paternity in the bull shark (Carcharhinus leucas)

2017 ◽  
Vol 68 (1) ◽  
pp. 195 ◽  
Author(s):  
Agathe Pirog ◽  
Sébastien Jaquemet ◽  
Marc Soria ◽  
Hélène Magalon
Keyword(s):  
Multiple Paternity ◽  
Western Indian Ocean ◽  
Reproductive Behaviour ◽  
Selection Processes ◽  
Carcharhinus Leucas ◽  
Management Plans ◽  
Bull Shark ◽  
Zygotic Selection ◽  
First Time

The present study assessed the occurrence of multiple paternity in four litters of bull shark Carcharhinus leucas (n=5, 8, 9 and 11 embryos) sampled at Reunion Island in the Western Indian Ocean. Using 21 microsatellite loci, we revealed that two litters were generated from two sires each, demonstrating for the first time multiple paternity for this species. We also reported a high paternal skew (10:1 in Litter 1 and 7:1 in Litter 3), which may be because of post-copulatory or post-zygotic selection processes. These results contribute to a better understanding of the reproductive behaviour of the bull shark, which remains poorly documented. The present study must be expanded to assess the frequency of multiple paternity in this species, and to test for genetic or cryptic benefits (convenience polyandry), which is important for long-term conservation and management plans.

scholarly journals NEW RECORDS AND PRELIMINARY REPRODUCTIVE ASPECTS OF ELASMOBRANCHS OF THE TRINDADE-MARTIN VAZ INSULAR COMPLEX

2021 ◽  
Vol 25 (01) ◽  
pp. 159-165
Author(s):  
Thierry Salmon ◽  
Bianca de Sousa Rangel ◽  
Carlos Eduardo Malavasi-Bruno ◽  
José Roberto Kfoury-Jr
Keyword(s):  
Abundant Species ◽  
Shark Species ◽  
Tiger Shark ◽  
Blue Shark ◽  
Galeocerdo Cuvier ◽  
Shortfin Mako ◽  
New Information ◽  
Thresher Shark ◽  
Pelagic Fishing ◽  
First Time

Here we presented records of elasmobranchs obtained during a longline pelagic fishing monitoring around the Trindade-Martin Vaz insular complex, including one new record. New information on the reproductive aspects of the blue shark (Prionace glauca) and pelagic stingray (Pteroplatytrygon violacea) suggest the use of this area as mating and parturition ground for these species. The most abundant species was the P. glauca (N = 65), followed by shortfin mako shark Isurus oxyrinchus (N = 12). We also recorded for the first time the smooth hammerhead shark Sphyrna zygaena (N = 3) and the bigeye thresher shark Alopias superciliosus (N = 2), and other shark species previous reported for the insular complex, including the oceanic whitetip Carcharhinus longimanus (N = 2), and the tiger shark Galeocerdo cuvier (N = 1). Our findings highlight the importance of further studies at the Trindade-Martin Vaz insular complex considering the pelagic biodiversity and reproductive aspects of elasmobranchs.

scholarly journals On the taxonomy of the first record of rare deep-water rough shark species of Oxynotidae (Chondrichthyes: Squaliformes) in the western Indian Ocean

2018 ◽  
Vol 10 (6) ◽  
pp. 11732
Author(s):  
Sarah Viana ◽  
Mark W. Lisher
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
First Record ◽  
Hepatosomatic Index ◽  
Shark Species ◽  
General Description ◽  
Intraspecific Variations ◽  
Eastern Atlantic Ocean ◽  
Viable Population ◽  
Morphological Differences

An immature female specimen of rough shark was collected south of Reunion Island in the Madagascar Basin in 2009 aboard R/V Dr. Fridtjof Nansen, representing the first official record of the family Oxynotidae in the western Indian Ocean.  The specimen is herein identified as Oxynotus sp. due to morphological differences with its closely similar congeners O. centrina and O. bruniensis regarding morphometrics, shape of dorsal, pectoral and caudal fins, shape of the head and colouration, refuting the hypothesis of occurrence of these two species in the region.  These results indicate that Oxynotus sp. is possibly an undescribed species.  A general description of the external morphology, external morphometrics and photographs of Oxynotus sp. are provided.  The specimen has a hepatosomatic index of 36.33% which reveals that it was possibly approaching maturation, suggesting that a viable population of Oxynotus sp. exists in the western Indian Ocean.  Intraspecific variations in O. centrina from the Mediterranean Sea and eastern Atlantic Ocean are also noticed, requiring further taxonomic scrutiny.  

Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean

2015 ◽  
Vol 37 (2) ◽  
pp. 199-208 ◽  
Author(s):  
A Blaison ◽  
S Jaquemet ◽  
D Guyomard ◽  
G Vangrevelynghe ◽  
T Gazzo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
West Coast ◽  
Seasonal Variability ◽  
Western Indian Ocean ◽  
Tiger Shark ◽  
Reunion Island ◽  
The West ◽  
Réunion Island

scholarly journals PARAMETER PERTUMBUHAN HIU MACAN (Galeocerdo cuvier Peron & Lesuer, 1822) DI PERAIRAN SELATAN NUSA TENGGARA BARAT

2019 ◽  
Vol 24 (4) ◽  
pp. 253 ◽  
Author(s):  
Umi Chodrijah ◽  
Agus Arifin Sentosa ◽  
Prihatiningsih Prihatiningsih
Keyword(s):  
Mortality Rate ◽  
Indian Ocean ◽  
Average Length ◽  
Conservation Status ◽  
Total Mortality ◽  
Landing Site ◽  
Iucn Red List ◽  
Tiger Shark ◽  
Galeocerdo Cuvier ◽  
Total Length

Hiu macan (Galeocerdo cuvier Peron & Lesuer, 1822) merupakan predator puncak yang ditandai dengan sebaran yang luas dan ukurannya lebih besar.  Spesies hiu ini masuk dalam famili Carcharhinidae yang banyak tertangkap di perairan Samudera Hindia. Status konservasi jenis ini masuk dalam Daftar merah IUCN dan hampir terancam (NT) serta informasi tentang biologi khususnya parameter pertumbuhan spesies ini masih sangat terbatas.Tujuan penelitian adalah untuk mendapatkan informasi parameter pertumbuhan hiu macan di perairan Samudera Hindia bagian Selatan Nusa Tenggara Barat. Penelitian dilakukan di tempat pendaratan ikan  Tanjung Luar, Lombok Timur pada bulan Januari sampai dengan Desember 2016. Pengamatan meliputi panjang total tubuh dan jenis kelamin yang dilakukan dengan pengukuran dan pengamatan langsung secara visual di lapangan. Hasil penelitian terhadap 808 ekor ikan contoh menunjukkan bahwa kisaran panjang total untuk hiu macan (Galeocerdo cuvier)  terdistribusi pada ukuran antara 116 - 400 cmTL dengan panjang rata-rata 242,8 cm TL serta modus pada ukuran 240 cmTL. Perbandingan kelamin ikan hiu macan  jantan dan betina dalam keadaan tidak seimbang, dengan jumlah jantan lebih besar.  Estimasi panjang asimtotik (L∞) sebesar 420 cmTL dengan laju pertumbuhan (K) 0,260/tahun, laju kematian total (Z)  1,10/tahun, laju kematian alamiah (M) 0,35/tahun serta laju kematian akibat penangkapan (F) 0,75/tahun. Estimasi laju eksploitasi sudah mengarah kepada penangkapan yang berlebih (E = 0,68) oleh karena itu perlu dilakukan tindakan pengelolaan agar pemanfaatannya tetap lestari.Tiger sharks (Galeocerdo cuvier Peron & Lesuer, 1822) were widely held in the depths of the Indian Ocean. Its conservation status was on the IUCN Red List and was near threatened (NT). The purpose of this study was to obtain the parameters of growth in the South off West Nusa Tenggara waters. The study was conducted at Tanjung Luar landing site, East Lombok in January until December 2016. The observation included total length and sex with visual measurement and observation in the field. The results of the study showed the number of 808 individues that the total length range for tiger shark (Galeocerdo cuvier) caught in Indian Ocean waters landed on Tanjung Luar was distributed on a size between 116-400 cmTL with an average length of 242.8 cmTL and a mode at 240 cmTL. The sex ratio of male and female tiger sharks was in an unbalanced state, with larger females. Estimation of asymptotic length (L∞) of 420 cmTL with growth rate (K) 0.260 / year, total mortality rate (Z) 1.10 / year, natural mortality rate (M) 0.35 / year and mortality rate due to arrest (F) 0.75 / year. Estimation of the rate of exploitation has led to overfishing (E = 0.68) therefore it was necessary to take regulatory and management measures to ensure sustainable utilization.

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