One of the most isolated populations of fin whales occurs in the Gulf of California (GOC) with 400-800 individuals. This population shows reduced neutral genetic variation in comparison to the North Pacific population and thus might also display limited adaptive polymorphism. We sampled 36 fin whales from the GOC and assessed genetic variation at exon 2 of the major histocompatibility complex class II DQB-1 genes responsible for eliciting immune responses. Three divergent alleles were found with higher nonsynonymous than synonymous substitution rates within the peptide-binding region positions as well as the likely retention of ancient alleles, indicating that positive selection has shaped diversity in this species. Limited levels of nonneutral polymorphism, in addition to previously described low levels of neutral polymorphism, are consistent with the results of previous studies on vertebrate populations that have remained small and demographically stable for a very long time. Such low genetic variation in the GOC fin whales could be explained by 2 demographic scenarios: an ancient isolated population with limited gene flow or a more recent founder event after the last glacial maximum with very restricted gene flow.
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http://dx.doi.org/10.1093/jhered/esm087 | DOI Listing |
J Fish Biol
January 2025
Key Laboratory of Aquatic Ecology and Aquaculture of Tianjin, College of Fisheries, Tianjin Agricultural University, Tianjin, People's Republic of China.
Understanding the developmental sequence characteristics of the vertebral and appendicular skeletons of the larvae and juveniles of Larimichthys crocea (Naozhou population) can provide theoretical basis for seedling cultivation, environmental adaptation, and taxonomic identification. The cartilage-bone double staining method was used to stain, observe, and analyse the vertebrae, pectoral fins, anal fins, caudal fins, and dorsal fins of the larvae and juveniles of L. crocea (0-30 days post-hatching [DPH]).
View Article and Find Full Text PDFPrevious studies have described two distinct vascular systems in cetacean fins. However, these studies have been limited to Delphinoidea species, with little information on their three-dimensional structures. In this study, the anatomical analysis of the caudal and dorsal fins of a dwarf sperm whale was conducted using X-ray computed tomography and gross dissection with staining, providing the first confirmation of the two vascular systems in the fins of the family Kogiidae.
View Article and Find Full Text PDFAnimals (Basel)
December 2024
Faculté des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada.
Anthropogenic activities impacting marine environments are internationally recognized as welfare issues for wild cetaceans. This study validates a first evidence-based physical indicator for the welfare assessment protocol of humpback (n = 50) and fin whales (n = 50) living in a highly anthropized environment. Visual assessments of body condition, skin health, prevalence of injuries and parasite/epibiont loads were performed using a species-specific multi-scale measuring tool.
View Article and Find Full Text PDFPLoS One
November 2024
Ocean Acoustics Group, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
Sci Total Environ
December 2024
Institute of Environmental Assessment and Water Research (IDAEA)-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
This study explores the behavior of organophosphate esters (OPEs) in different species within marine ecosystems and their potential for bioaccumulation and biomagnification. The concentrations of OPEs were analyzed in marine species (krill (Meganyctiphanes norvegica), jellyfish (Pelagia noctiluca), European sardine (Sardina pilchardus), European anchovy (Engraulis encrasicolus), European hake (Merluccius merluccius), loggerhead turtle (Caretta caretta), European squid (Loligo vulgaris), fin whale (Balaenoptera physalus) and striped dolphin (Stenella coeruleoalba)) from different trophic levels, to understand their distribution and contamination profiles. The study provides insights into the metabolism of OPEs and their biomagnification on species occupying higher trophic levels.
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