The shortfin mako shark () demonstrates low productivity and is thus relatively sensitive to fishing. Natural mortality () and fishing mortality () data are critical to determine their population dynamics. However, catch and fishing effort data are unavailable for this species in the South Pacific Ocean, making stock assessments difficult. Demographic quantitative methods aid in analyzing species with limited data availability. We used a two-sex stage-structured matrix population model to examine the demographic stock status of mako sharks. However, data-limited models to determine fishery management strategies have limitations. We performed Monte Carlo simulations to evaluate the effects of uncertainty on the estimated mako shark population growth rate. Under unfished conditions, the simulations demonstrated that the mako sharks showed a higher finite population growth rate in the 2-year reproductive cycle compared to the 3-year reproductive cycle. Protecting immature mako sharks led to a higher population growth rate than protecting mature mako sharks. According to the sex-specific data, protecting immature male and female sharks led to a higher population growth rate than protecting mature male and female sharks. In conclusion, sex-specific management measures can facilitate the sustainable mako shark conservation and management.
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http://dx.doi.org/10.3390/ani12223229 | DOI Listing |
Ecotoxicol Environ Saf
December 2024
Sea Shepherd Brazil, São Paulo, Brazil.
Elasmobranchs, including sharks, rays, and skates, are a global protein source but face threats from overfishing and population declines. Despite their lower market value, increased consumption raises sustainability and public health concerns. Commonly landed species like the Blue Shark, Shortfin Mako, and Spiny Dogfish are particularly vulnerable to bioaccumulation of metals such as mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As), posing health risks to consumers.
View Article and Find Full Text PDFActa Biomater
November 2024
Department of Chemistry and Biochemistry, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431, USA. Electronic address:
Shark cartilage presents a complex material composed of collagen, proteoglycans, and bioapatite. In the present study, we explored the link between microstructure, chemical composition, and biomechanical function of shark vertebral cartilage using Polarized Light Microscopy (PLM), Atomic Force Microscopy (AFM), Confocal Raman Microspectroscopy, and Nanoindentation. Our investigation focused on vertebrae from Blacktip and Shortfin Mako sharks.
View Article and Find Full Text PDFBiomimetics (Basel)
July 2024
Department of Mechanical Engineering, Universidad de La Frontera, Temuco 4780000, Chile.
The automotive industry continuously enhances vehicle design to meet the growing demand for more efficient vehicles. Computational design and numerical simulation are essential tools for developing concept cars with lower carbon emissions and reduced costs. Underground roads are proposed as an attractive alternative for reducing surface congestion, improving traffic flow, reducing travel times and minimizing noise pollution in urban areas, creating a quieter and more livable environment for residents.
View Article and Find Full Text PDFJ R Soc Interface
August 2024
School of Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku , Tokyo 152-8550, Japan.
The ridges of the dermal denticles of migratory sharks have inspired riblets to reduce the frictional drag of a fluid. In particular, the dermal denticles of white sharks () are characterized by a high middle ridge and low side ridges. The detailed morphology of their denticles and their variation along the body, however, have never been investigated.
View Article and Find Full Text PDFBiomimetics (Basel)
June 2024
Department of Aerospace Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.
The passive bristling mechanism of the scales on the shortfin mako shark () is hypothesized to play a crucial role in controlling flow separation. In the hypothesized mechanism, the scales are triggered in response to patches of reversed flow at the onset of separation occurring in the low-speed streaks that form in a turbulent boundary layer. The two goals of this investigation were as follows: (1) to measure the reversing flow occurring within the low-speed streaks in a separating turbulent boundary layer; (2) to understand the passive flow control mechanism of movable shark skin scales that inhibit reversing flow within the low-speed streaks.
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