scholarly journals Aerial Survey as a Tool to Estimate Abundance and Describe Distribution of a Carcharhinid Species, the Lemon Shark,Negaprion brevirostris

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
S. T. Kessel ◽  
S. H. Gruber ◽  
K. S. Gledhill ◽  
M. E. Bond ◽  
R. G. Perkins
Keyword(s):  
High Tide ◽  
Central Area ◽  
Aerial Survey ◽  
Successful Implementation ◽  
Shark Species ◽  
Lemon Shark ◽  
Test Species ◽  
Negaprion Brevirostris ◽  
Coastal Marine ◽  
High Site

Aerial survey provides an important tool to assess the abundance of both terrestrial and marine vertebrates. To date, limited work has tested the effectiveness of this technique to estimate the abundance of smaller shark species. In Bimini, Bahamas, the lemon shark (Negaprion brevirostris) shows high site fidelity to a shallow sandy lagoon, providing an ideal test species to determine the effectiveness of localised aerial survey techniques for a Carcharhinid species in shallow subtropical waters. Between September 2007 and September 2008, visual surveys were conducted from light aircraft following defined transects ranging in length between 8.8 and 4.4 km. Count results were corrected for “availability”, “perception”, and “survey intensity” to provide unbiased abundance estimates. The abundance of lemon sharks was greatest in the central area of the lagoon during high tide, with a change in abundance distribution to the east and western regions of the lagoon with low tide. Mean abundance of sharks was estimated at 49 (±8.6) individuals, and monthly abundance was significantly positively correlated with mean water temperature. The successful implementation of the aerial survey technique highlighted the potential of further employment for shark abundance assessments in shallow coastal marine environments.

Functional morphology of the olfactory organ of two carcharhinid shark species

1987 ◽  
Vol 65 (10) ◽  
pp. 2406-2412 ◽  
Author(s):  
Eckart Zeiske ◽  
Birgit Theisen ◽  
Samuel H. Gruber
Keyword(s):  
Ventral Side ◽  
Sensory Epithelium ◽  
Shark Species ◽  
Basal Cells ◽  
Lemon Shark ◽  
Negaprion Brevirostris ◽  
Receptor Cells ◽  
Silky Shark ◽  
Inlet Chamber ◽  
Outlet Chamber

The paired olfactory organs of both the lemon shark (Negaprion brevirostris) and the silky shark (Carcharhinus falciformis) are located in solid cartilaginous nasal capsules, which open at the ventral side of the snout and are entirely separate from the mouth. The olfactory rosette consists of two rows of lamellae arising from a central raphe. The lamellae possess secondary folds covered with sensory epithelium, which contains microvillous receptor cells, supporting cells with both cilia and microvilli, basal cells, and goblet cells. No ciliated receptor cells were found. Gaps between facing lamellae connect the inlet chamber with the outlet chamber. The inlet chamber receives the ventilatory water through the incurrent nostril and the outlet chamber discharges the water through the excurrent nostril. A nasal flap, a septum, and paired valve flaps form an incomplete barrier between incurrent and excurrent nostrils and may have hydrodynamic functions, which are discussed.

scholarly journals Description of the microbiota in epidermal mucus and skin of sharks (Ginglymostoma cirratum and Negaprion brevirostris) and one stingray (Hypanus americanus)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10240
Author(s):  
Susana Caballero ◽  
Ana Maria Galeano ◽  
Juan Diego Lozano ◽  
Martha Vives
Keyword(s):  
Microbial Communities ◽  
Pathogenic Bacteria ◽  
Rrna Gene ◽  
Shark Species ◽  
Lemon Shark ◽  
Skin Mucus ◽  
Negaprion Brevirostris ◽  
Opportunistic Bacteria ◽  
Ginglymostoma Cirratum ◽  
Skin Samples

Skin mucus in fish is the first barrier between the organism and the environment but the role of skin mucus in protecting fish against pathogens is not well understood. During copulation in sharks, the male bites the female generating wounds, which are then highly likely to become infected by opportunistic bacteria from the water or from the male shark’s mouth. Describing the microbial component of epithelial mucus may allow future understanding of this first line of defense in sharks. In this study, we analyzed mucus and skin samples obtained from 19 individuals of two shark species and a stingray: the nurse shark (Ginglymostoma cirratum), the lemon shark (Negaprion brevirostris) and the southern stingray (Hypanus americanus). Total DNA was extracted from all samples, and the bacterial 16S rRNA gene (region V3-V4) was amplified and sequenced on the Ion Torrent Platform. Bacterial diversity (order) was higher in skin and mucus than in water. Order composition was more similar between the two shark species. Alpha-diversities (Shannon and Simpson) for OTUs (clusters of sequences defined by a 97% identity threshold for the16S rRNA gene) were high and there were non-significant differences between elasmobranch species or types of samples. We found orders of potentially pathogenic bacteria in water samples collected from the area where the animals were found, such as Pasteurellales (i.e., genus Pasteurella spp. and Haemophilus spp.) and Oceanospirillales (i.e., genus Halomonas spp.) but these were not found in the skin or mucus samples from any species. Some bacterial orders, such as Flavobacteriales, Vibrionales (i.e., genus Pseudoalteromonas), Lactobacillales and Bacillales were found only in mucus and skin samples. However, in a co-occurrence analyses, no significant relationship was found among these orders (strength less than 0.6, p-value > 0.01) but significant relationships were found among the order Trembayales, Fusobacteriales, and some previously described marine environmental Bacteria and Archaea, including Elusimicrobiales, Thermoproteales, Deinococcales and Desulfarculales. This is the first study focusing on elasmobranch microbial communities. The functional role and the benefits of these bacteria still needs understanding as well as the potential changes to microbial communities as a result of changing environmental conditions.

Anatomy of the feeding apparatus of the lemon shark,Negaprion brevirostris

1995 ◽  
Vol 226 (3) ◽  
pp. 309-329 ◽  
Author(s):  
Philip J. Motta ◽  
Cheryl A. D. Wilga
Keyword(s):  
Feeding Apparatus ◽  
Lemon Shark ◽  
Negaprion Brevirostris

Demography of the central california population of the Leopard Shark (Triakis semifasciata)

1992 ◽  
Vol 43 (1) ◽  
pp. 183 ◽  
Author(s):  
GM Cailliet
Keyword(s):  
Population Growth ◽  
Reproductive Rate ◽  
Shark Species ◽  
Sandbar Shark ◽  
Lemon Shark ◽  
Carcharhinus Plumbeus ◽  
Net Reproductive Rate ◽  
Leopard Shark ◽  
Triakis Semifasciata ◽  
Leopard Sharks

Demographic analyses can be quite useful for effectively managing elasmobranch fisheries. However, they require valid estimates of age-specific mortality and natality rates, in addition to information on the distribution, abundance, habits and reproduction of the population, to produce reliable estimates of population growth. Because such detailed ecological information is usually unavailable, complete demographic analyses have been completed for only four shark species: the spiny dogfish, Squalus acanthias; the soupfin shark, Galeorhinus australis; the lemon shark, Negaprion brevirostris; and most recently the sandbar shark, Carcharhinus plumbeus. In California, reliable estimates of age, growth, mortality, age at maturity, and fecundity are available only for the leopard shark, Triakis semifasciata. A demographic analysis of this species yielded a net reproductive rate (Ro) of 4.467, a generation time (G) of 22.35 years, and an estimate of the instantaneous population growth coefficient (r) of 0.067. If the mean fishing pressure over 10 years (F= 0.084) is included in the survivorship function, Ro and r are reduced considerably, especially if leopard sharks first enter the fishery at early ages. A size limit of 120 cm TL (estimated age 13 years), especially for female sharks, is tentatively proposed for the leopard shark fishery.

RECONSTRUCTION OF PARENTAL MICROSATELLITE GENOTYPES REVEALS FEMALE POLYANDRY AND PHILOPATRY IN THE LEMON SHARK, NEGAPRION BREVIROSTRIS

Evolution ◽  
2004 ◽  
Vol 58 (10) ◽  
pp. 2332 ◽  
Author(s):  
Kevin A. Feldheim ◽  
Samuel H. Gruber ◽  
Mary V. Ashley
Keyword(s):  
Lemon Shark ◽  
Negaprion Brevirostris

scholarly journals Assortative interactions and leadership in a free-ranging population of juvenile lemon shark Negaprion brevirostris

2011 ◽  
Vol 423 ◽  
pp. 235-245 ◽  
Author(s):  
TL Guttridge ◽  
SH Gruber ◽  
JD DiBattista ◽  
KA Feldheim ◽  
DP Croft ◽  
...  
Keyword(s):  
Lemon Shark ◽  
Negaprion Brevirostris ◽  
Free Ranging

scholarly journals Nursery area and size structure of the lemon shark population, Negaprion brevirostris (Poey, 1868), in Los Roques Archipelago National Park, Venezuela

2016 ◽  
Vol 21 (1) ◽  
pp. 33 ◽  
Author(s):  
Rafael Tavares ◽  
Jon Paul Rodriguez ◽  
Misael Morales
Keyword(s):  
Management Strategy ◽  
Size Structure ◽  
Size Composition ◽  
Nursery Area ◽  
Lemon Shark ◽  
Ecological Benefits ◽  
Time Activity ◽  
Negaprion Brevirostris ◽  
Lemon Sharks ◽  
Different Sources

The protection of the habitats used by juvenile sharks is a management strategy that has recently caught the attention of fishery biologists. In the present study, we evaluated the population of the lemon shark (<em>Negaprion brevirostris</em>) from Los Roques Archipelago in order to identify the nursery area, describe the size composition, and examine the variation in nocturnal activity of the juvenile individuals. The data analysed came from three different sources: commercial shark fishery, tag-recapture sampling, and visual records. A total of 375 lemon sharks with total lengths between 55 and 281 cm were recorded during the study period. Overall data showed that the area occupied by juvenile lemon sharks was clearly partitioned into primary and secondary nurseries. Additionally, nighttime activity seemed to change according to the size of sharks in the primary nursery, suggesting a reduction of time activity overlapping among juveniles of distinct size/age. Results suggest that the strategy of utilization of the primary nurseries by the lemon shark may lead to important ecological benefits by reducing the competition, predation and natural mortality.

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