Most mesopelagic fishes perform large diel vertical migrations from the deep-sea zone to the surface. Although there is a trade-off between a higher food availability at the upper layers and an energy cost and predation risk, incursion towards the surface also implies a transport by currents, where the fish are exposed to a stranding risk on the coast. Here, we reported the first documented stranding of mesopelagic fishes along the southeast shore of Gran Canaria Island. Our study hypothesized that (1) the influence of the Canary Current, (2) the dominant incidence of the Trade Winds during summer, and (3) the presence of an upwelling filament coupled with an anticyclonic eddy south of Gran Canaria Island were the causative mechanisms of the strandings. (Myctophidae family) was the main species found as observed from an external morphological analysis using traditional taxonomy. The otolith contour analysis suggested the presence of other spp. and . Nevertheless, the otolith morphological features described in the literature suggested that all the specimens were actually . Errors in the identification were mainly due to the high intraspecific variability found in the otolith morphology. Even so, two patterns of oval and elliptic shapes were described with significant differences in its morphometry.
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http://dx.doi.org/10.3390/ani12243465 | DOI Listing |
Dokl Biol Sci
December 2024
Institute of Biology, Karelian Research Center, Russian Academy of Sciences, Petrozavodsk, Russia.
The contents of main classes of storage lipids (triacylglycerols, cholesterol esters, and waxes) in muscles and the liver of the beaked redfish Sebastes mentella were studied across the depth gradient and in different areas of the North Atlantic. Significant differences in storage lipid contents were observed between fish from different fishing horizons. The depth-dependent changes in lipids in fish tissues and organs were assumed to indicate that triacylglycerols (TAGs), cholesterol esters (CEs), and waxes are utilized as energy sources, in particular, to maintain the buoyancy during vertical migration.
View Article and Find Full Text PDFEcol Lett
September 2024
MARBEC, University of Montpellier, CNRS, Ifremer, IRD, Sète, France.
J Fish Biol
December 2024
Department of Biological Sciences, Florida International University, North Miami, Florida, USA.
In June 2024, a large female oceanic whitetip shark (Carcharhinus longimanus) was observed near San Andres Island, Colombia, bearing at least 41 healed circular scars on its skin. These scars, resembling those left by cookiecutter sharks on large teleost species, suggest repeated predation events. Cookiecutter sharks typically leave one or two bite marks per prey item, with a small percentage showing five or more marks.
View Article and Find Full Text PDFPLoS One
September 2024
CNRS, IRD, Ifremer, LEMAR, Univ Brest, Plouzané, Brest, France.
The impact of a cyclonic (C), an anticyclonic (AC) eddy and transition zone (TZ), which is the area between the two eddies, on acoustic groups representing various mesopelagic organisms, was investigated using a semi-supervised multifrequency classification approach (hereafter, Escore algorithm). The Escore algorithm involved selecting regions of interest (ROIs) within multifrequency (18, 38, 70, and 120 kHz) echograms and classifying into four clusters or echo-classes using Sv differences (Sv18-38, Sv70-38, and Sv120-38). Acoustic densities and diel vertical migration strength varied between the AC, C, and TZ according to the frequency.
View Article and Find Full Text PDFMar Pollut Bull
November 2024
College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai, China.
We employed Fourier infrared spectroscopy, laser infrared technology, and stable isotope analysis to investigate the relationships between characteristics of ingested plastics and size-related feeding ecology of a mesopelagic predator, longnose lancetfish Alepisaurus ferox. Plastics were detected in 81.48 % of specimens, up to 8.
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