scholarly journals Notes on the Bull shark Carcharhinus leucas in the lagoon region of Cananéia, Brazil

1971 ◽  
Vol 20 (2) ◽  
pp. 71-78 ◽  
Author(s):  
V Sadowsky
Keyword(s):  
Stomach Contents ◽  
Abundant Species ◽  
Feeding Inhibition ◽  
Adult Females ◽  
Carcharhinus Leucas ◽  
Caudal Vertebrae ◽  
Open Sea ◽  
Bull Shark

Ninety one young specimens and 3 adult females of BulI shark ("cação cabeça chata") caught in the lagoon region of Cananéia were examined, their tooth formula being 27/25 and the number of pre-caudal vertebrae ranging from 109 to 115. The proportion between the 1st and 2nd dorsal fins were found to be 2.3 and 2.8 for the young,and 2.9 to 3.1 for the adults. These data confirm that the studied form belongs to C. leuoas. Young occur regularly but in limited numbers.As regards the adults, however, females only appear during the short parturition period, i.e., from November to February. The number of embryos in the litters were from 7 to 9, their sizes ranging between 768-812 mm. The length of the smallest free young found was 697 mm, but young presumably 9 to 12 months old had 98 to 112 cm; between 21 and 24 months they were reaching 124 to 128 cm, that is, the same size they have when they start migrating to the open sea. The feeding inhibition phenomenon during the period of parturition was not observed in the female specimens caught in the lagoon. The more abundant species found in the stomach contents were: Arius spixii; Chloroscombrus chrysurus; A. grandicassus; A. barbus; Felichtys marinus; Genidens genidens; Chanophorus tajacica and Carcharhinus porosus.

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.

A multi-faceted approach for quantifying the estuarine - nearshore transition in the life cycle of the bull shark, Carcharhinus leucas

2011 ◽  
Vol 62 (12) ◽  
pp. 1421 ◽  
Author(s):  
J. M. Werry ◽  
S. Y. Lee ◽  
N. M. Otway ◽  
Y. Hu ◽  
W. Sumpton
Keyword(s):  
Habitat Use ◽  
Acoustic Telemetry ◽  
Inductively Coupled Plasma ◽  
Stomach Contents ◽  
Inductively Coupled ◽  
Carcharhinus Leucas ◽  
Bull Shark ◽  
Plasma Mass Spectrometry ◽  
Shark Attacks ◽  
Δ15n And Δ13c

Understanding the ontogenetic habitat linkages of sharks is important for conservation and managing human interactions. We used acoustic telemetry, catch data, elemental and stable isotope signatures and dietary analyses to investigate ontogenetic habitat use in south-east Queensland, Australia, by the bull shark Carcharhinus leucas, a IUCN ‘near-threatened’ species that is implicated in many shark attacks on humans in urban estuaries. Sequential analyses for δ15N and δ13C of vertebrae from five adult C. leucas and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) for elemental composition from 23 C. leucas, including a pregnant female, were also used to trace ontogenetic habitat dependence. Acoustic telemetry indicated large juvenile and subadult C. leucas remained in estuarine habitats. δ15N values across shark vertebrae showed an ontogenetic shift in diet with total length (TL), confirmed by stomach contents. LA-ICPMS data reflected the ontogenetic movements of C. leucas from natal habitats. Differences among adults were gender related. Shifts in habitat use by subadults were correlated with a sigmoidal δ13C relationship with TL. C. leucas have a multipartite, stage-specific dependency in their transition between habitats along the freshwater–estuarine–marine continuum, making them particularly susceptible to the habitat alteration that is occurring globally.

scholarly journals Variable response to electric shark deterrents in bull sharks, Carcharhinus leucas

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. R. G. Gauthier ◽  
E. Chateauminois ◽  
M. G. Hoarau ◽  
J. Gadenne ◽  
E. Hoarau ◽  
...  
Keyword(s):  
New Caledonia ◽  
White Shark ◽  
Mitigation Measures ◽  
Control Board ◽  
Variable Response ◽  
Carcharodon Carcharias ◽  
Behavioural Changes ◽  
Carcharhinus Leucas ◽  
Bull Shark ◽  
Over Time

Abstract Although relatively rare, human-shark interactions and sharks bites are increasing globally, which has led to the development of various mitigation measures. Electric shark deterrents (ESDs) have, so far, been the most effective personal deterrents, but have only been scientifically tested on one of the species most frequently responsible for shark bites, i.e. white shark (Carcharodon carcharias). We tested the effectiveness of five ESDs (E-Shark Force, NoShark, Rpela v2, Freedom + Surf, Freedom + Surf—Shortboard) on bull sharks, Carcharhinus leucas, over a period of 21 days in September 2019, in New Caledonia. Standardised bait was attached 30 cm below an experimental board that had an active ESD for up to 15 min, or until a bull shark touched the bait or the board. We compared the numbers of baits taken, numbers of passes and reactions around the board, as well as the distance between the sharks and the board among ESDs and against a control board with bait and no active ESD. The Freedom + Surf was the most effective ESD, reducing the amounts of baits taken by 42.3%, while the Rpela v2 and Freedom + Surf—Shortboard also significantly reduced the number of baits taken by 16.5% and 16.2% respectively. Mean distance between sharks and the bait was not affected by the ESDs, but the number of approaches and the proportion of reactions were both significantly higher when the Freedom + Surf was active compared to other ESDs. The effectiveness of all ESDs decreased over time, with the likelihood of the bait being taken increasing and the number of approaches and distance between sharks and the bait decreasing. Our findings show that the ability of ESDs to deter bull shark varies between products, with the Freedom + Surf resulting in the most behavioural changes, followed by the Rpela v2 and Freedom + Surf—Shortboard. However, none of the products tested completely stopped sharks from taking the bait.

scholarly journals On the Food of Young Plaice (Pleuronectes platessa)

1922 ◽  
Vol 12 (4) ◽  
pp. 678-687 ◽  
Author(s):  
Andrew Scott
Keyword(s):  
Present Report ◽  
Stomach Contents ◽  
Annual Reports ◽  
Irish Sea ◽  
Pleuronectes Platessa ◽  
Larval Stages ◽  
Marine Biological Association ◽  
Open Sea ◽  
Pelagic Eggs ◽  
The Irish Sea

The investigation of the food contents in the stomachs of young fishes was included in the scheme of scientific investigations drawn up and initiated by Professor Herdman for the Lancashire Sea Fisheries Committee nearly thirty years ago. The lengthy series of Annual Reports contain here and there accounts of the observations made on the stomach contents of various Pleuronectidæ captured close inshore, and the pelagic stages of other fishes caught from time to time in the plankton tow-nets. No systematic attempt has, however, been made, in connection with the investigation of the Irish Sea, to determine the food of any particular species of fish during the early part of its life history.Other observers working in other areas, notably Dr. Marie Lebour at Plymouth, have added very much to our knowledge of the early food of young fishes. Dr. Lebour's reports, published in the Journal of the Marine Biological Association, Vols. XI and XII, deal with a very large number of larval and post-larval stages of the more important food fishes caught in the tow-nets and young fish-trawl in Plymouth Sound and beyond.The present report gives an account of the food contained in the stomachs of young plaice (Pleuronectes platessa, Linn.) from a few days after hatching to about five months old. The samples examined in April and May were taken from the spawning pond at Port Erin, Isle of Man, where they had hatched from the pelagic eggs spawned by the adult plaice early in 1921. The later stages examined during May to August represented young plaice hatched in the open sea about the same time as those in the pond, and which had made their way close inshore.

The Status of the Bull Shark, Carcharhinus leucas, in the Amazon River

Copeia ◽  
1972 ◽  
Vol 1972 (3) ◽  
pp. 601 ◽  
Author(s):  
Thomas B. Thorson
Keyword(s):  
Amazon River ◽  
Carcharhinus Leucas ◽  
The Status ◽  
Bull Shark

scholarly journals First photographic inland records of bull shark Carcharhinus leucas (Carcharhiniformes: Carcharhinidae) in Sumatran waters, Indonesia

2019 ◽  
Vol 22 ◽  
pp. 171-176
Author(s):  
Muhammad Iqbal ◽  
Elisa Nurnawati ◽  
Arum Setiawan ◽  
Zulkifli Dahlan ◽  
Indra Yustian
Keyword(s):  
River Basin ◽  
Nursery Area ◽  
Carcharhinus Leucas ◽  
Bull Shark ◽  
Musi River ◽  
Photographic Records

Two specimens (c.700 mm) of bull sharks Carcharhinus leucas (Müller & Henle, 1839) were caught and photographed by fishermen using trammel net on 29 September and 1 October 2017 in Musi River, South Sumatra province, Indonesia. These photos are considered as second record after 20 years (1997-2017), and first confirm inland record for Sumatra. Photographic records indicate specimens of C. leucas found in Musi River basin recorded about 75 km inland, and apparently very young juveniles. Further study and monitoring is needed to asses the possibility of the importance of Musi River basin as nursery area of C. leucas.

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