A tradeoff evolution between acoustic fat bodies and skull muscles in toothed whales.

Toothed whales have developed specialized echolocation abilities that are crucial for underwater activities. Acoustic fat bodies, including the melon, extramandibular fat body, and intramandibular fat body, are vital for echolocation. This study explores the transcriptome of acoustic fat bodies in toothed whales, revealing some insight into their evolutionary origins and ecological significance.

Notes on stomach contents of pygmy and dwarf sperm whales (Kogia spp.) from around Japan.

The diets of pygmy (Kogia breviceps) and dwarf (K. sima) sperm whales in Japanese waters are poorly known. We report new information on the diets of these two species from these waters based on identifiable hard-part remains recovered from the stomach contents of 29 whales (11 pygmy and 18 dwarf sperm whales) that stranded between 1991 and 2021; those of a further two dwarf sperm whales were empty.

Assessing the costs of GHG emissions of multi-product agricultural systems in Vietnam.

Besides a vital sector of the economy, agriculture is a primary source of greenhouse gas (GHG) emissions. The present paper investigates the impact of carbon tax policy on Vietnamese agriculture by focusing on multi-product systems such as rice, livestock, and aquaculture, traditionally called the Vuon (Garden)-Ao (Pond)-Chuong (livestock pen) system (VAC). In it, farmers use garden, pond, and pen by-products as fertilizer and feed.

Diphyllobothrium stemmacephalum (Cestoda: Diphyllobothriidae) found from a harbor porpoise in northern Japan, with comments on a geographical gap with human infection cases in southern Japan.

Even though the cetacean tapeworm Diphyllobothrium stemmacephalum occurs in both cold and warm waters, human infections and final host occurrences have been confined to temperate areas in and near Japan. We recently obtained a strobila of this cestode that was excreted from a harbor porpoise accidentally caught offshore of Hokkaido of northern Japan. Genetic analysis of 28S rDNA and cox1 genes confirmed that the cestode was D.

Gastric ulceration caused by genetically identified Anisakis simplex sensu stricto in a harbor porpoise from the Western Pacific stock.

The genus Anisakis is a well-known group of nematodes that parasitize cetaceans as the final host and cause mucosal damage to their stomach. However, little has been done to precisely identify the nematodes recovered from the final hosts, especially in the Western Pacific, because of taxonomic confusion about the discrimination of sibling species and the difficulties of obtaining specimens from cetaceans. We describe the results of genetic identification and histopathological observations of specimens recovered from an ulcerated lesion and stomach contents in the forestomach of a female harbor porpoise accidentally caught by a set net fishery in Usujiri, southern Hokkaido, Japan.

Foraging activity of harbour porpoises around a bottom-gillnet in a coastal fishing ground, under the risk of bycatch.

Bycatch of harbour porpoises (Phocoena phocoena) by gillnets is a recognised threat to populations. To develop effective mitigation measures, understanding the mechanics of bycatch is essential. Previous studies in experimental conditions suggested foraging activity is an important factor influencing porpoises' reaction to gillnets.

Description of a new species of beaked whale (Berardius) found in the North Pacific.

Two types of Berardius are recognised by local whalers in Hokkaido, Japan. The first is the ordinary Baird's beaked whale, B. bairdii, whereas the other is much smaller and entirely black.

Surveillance of amyloidosis in stranded and bycaught cetaceans off Hokkaido, Japan.

Systemic amyloidosis is rarely reported among cetaceans, and a surveillance dedicated for its occurrence across a certain geographic location has not been reported. Between 2013 and 2018, comprehensive gross and histopathologic examinations were conducted on 54 animals comprising 11 species of stranded and bycaught cetaceans in Hokkaido, Japan. Systemic amyloidosis was diagnosed in 2 out of 3 Stejneger's beaked whales (Mesoplodon stejnegeri), through Congo red staining and immunohistochemistry for amyloid A.

Different profiles of naturally produced and anthropogenic organohalogens in the livers of cetaceans from the Sea of Japan and the North Pacific Ocean.

Levels and profiles of naturally produced halogenated bipyrroles (BrCl-DBP and Cl-MBP), methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47), anthropogenic perfluoroalkyl substances (PFASs) and legacy persistent organic pollutants (POPs) were investigated in the livers of 14 cetaceans from the Sea of Japan and the North Pacific Ocean. The concentrations of BrCl-DBP (4 to 4900 ng/g-wet), Cl-MBP (16 to 3960 ng/g-wet) and 6-MeO-BDE47 (7 to 190 ng/g-wet) were higher in the order of killer whales > toothed whales > baleen whales. Profiles of PFASs were dominated by perfluoroundecanoic and perfluorotridecanoic acids (10 to 540 ng/g-wet), sum of which accounted for 70% of total measured PFASs.

Click emission in Dall's porpoise Phocoenoides dalli, focusing on physical properties of tissues.

Dall's porpoise (Phocoenoides dalli) is one of most common North Pacific porpoise species, for which information on sound-emitting processes is limited. To evaluate the mechanism of click emission in the head of this porpoise, the distribution of acoustic impedance in head tissues was calculated using density and Young's modulus'which is a measure of linear resistance to linear compression. Two Dall's porpoise heads were examined: one for macroscopic dissection, and one for investigating the distribution of acoustic impedance calculated from CT-measured density, and Young's modulus measured by creep meter.

Prominent hepatic ductular reaction induced by Oschmarinella macrorchis in a Hubbs' beaked whale Mesoplodon carlhubbsi, with biological notes.

Beaked whales are among the least known group of cetaceans, and information regarding their pathology and parasitology is especially scarce. We describe a case of significant parasitism by a trematode found in the liver of an adult male Hubbs' beaked whale Mesoplodon carlhubbsi that stranded in Hokkaido, Japan. Post-mortem examinations revealed a localised area of discolouration restricted to the hilar region of the left hepatic lobe, where spindle-shaped trematodes occupied the dilated and hypertrophic bile ducts.

Tissue-specific bioaccumulation of long-chain perfluorinated carboxylic acids and halogenated methylbipyrroles in Dall's porpoises (Phocoenoides dalli) and harbor porpoises (Phocoena phocoena) stranded in northern Japan.

This study investigated accumulation of perfluoroalkyl substances (PFASs), persistent organochlorines (OCs), and naturally produced halogenated compounds (NHCs), including brominated methylbipyrroles and methoxylated bromodiphenyl ethers, in liver, blood, and blubber from Dall's porpoises (Phocoenoides dalli) and harbor porpoises (Phocoena phocoena) stranded in Hokkaido, northern Japan. Profiles of the PFASs were dominated by perfluoroundecanoic acid and perfluorotridecanoic acid, both of which accounted for 70% of the total measured PFAS concentrations in both porpoise species. The mean concentrations of the ∑PFCA were 573ng/g wet weight (ng/g-wet) in liver, 62ng/g-wet in whole blood, and 28ng/g-wet in blubber from the Dall's porpoises, and were significantly higher (p<0.

Polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues in the blood of harbor, Dall's and finless porpoises from the Japanese coastal waters.

This study investigated the accumulation of polybrominated diphenyl ethers (PBDEs) and their hydroxylated and methoxylated analogues (OH-PBDEs and MeO-PBDEs) in the blood of harbor porpoises, Dall's porpoises, and finless porpoises stranded or bycaught in Japanese coastal waters and in the North Pacific Ocean. Moreover, we suggested the origins of these contaminants and the factors affecting their pattern of accumulation. Levels of PBDEs in Dall's porpoises were one order of magnitude greater than those in the other species.

Concentration and congener pattern of polychlorinated biphenyls in blubber and liver of Hubbs' beaked whale (Mesoplodon carlhubbsi), using a sulfoxide and an Ag-ION solid phase extraction cartridge as a simplified cleanup technique for biological samples.

We performed the first known study of polychlorinated biphenyls (PCBs) concentrations and patterns in the blubber and liver of a Hubbs' beaked whale. Samples were pretreated with Supelclean™ sulfoxide and Discovery® Ag-ION solid phase extraction cartridges to remove whale oil. PCB concentrations in the blubber and liver were 13,000 and 7300ng/g lipid, respectively.

Tissue physical property of the harbor porpoise Phocoena phocoena for investigation of the sound emission process.

The process by which sound is propagated in the head of a toothed whale is still a subject of discussion. Investigating the distribution of acoustic impedance calculated by density and Young's modulus is effective for quantitative comprehension because acoustic impedance determines the reflection coefficient of a sound wave. However, the sound propagation process of the toothed whale has been mainly examined by either anatomical techniques or the measurement of density or sound velocity.

Brown adipose tissue in cetacean blubber.

Brown adipose tissue (BAT) plays an important role in thermoregulation in species living in cold environments, given heat can be generated from its chemical energy reserves. Here we investigate the existence of BAT in blubber in four species of delphinoid cetacean, the Pacific white-sided and bottlenose dolphins, Lagenorhynchus obliquidens and Tursiops truncates, and Dall's and harbour porpoises, Phocoenoides dalli and Phocoena phocoena. Histology revealed adipocytes with small unilocular fat droplets and a large eosinophilic cytoplasm intermingled with connective tissue in the innermost layers of blubber.

Stable isotope ratios of carbon, nitrogen and oxygen in killer whales (Orcinus orca) stranded on the coast of Hokkaido, Japan.

We analyzed δ(13)C, δ(15)N and δ(18)O in the muscle and liver from killer whales stranded on the coast of Japan. The δ(15)N values in the muscle samples from calves were apparently higher than those in their lactating mothers, suggesting that nursing may result in the higher δ(15)N values in the muscle samples of calves. The δ(15)N value in the muscle samples of male and female whales, except for the calves, were positively correlated with the δ(13)C values and body length, suggesting that the increases in δ(15)N were due to the growth of the whales and increase in their trophic level.

Halogenated phenolic contaminants in the blood of marine mammals from Japanese coastal waters.

Information on accumulation of halogenated phenolic contaminants in the blood of marine mammal is limited. The present study, we determined the residue levels and patterns of chlorinated and brominated phenolic contaminants (OH-PCBs, OH-PBDEs and bromophenols) in the blood collected from pinnipeds (northern fur seal, spotted seal, Steller sea lion and ribbon seal) and small cetaceans (harbor porpoise and Dall's porpoise) from Japanese coastal waters. Concentrations of PCBs and OH-PCBs found in pinnipeds were the same as in small cetaceans living in the same coastal area.

Accumulation of hydroxylated polychlorinated biphenyls (OH-PCBs) and implications for PCBs metabolic capacities in three porpoise species.

The present study investigated polychlorinated biphenyls (PCBs) and hydroxylated metabolites of PCBs (OH-PCBs) in blood from three porpoise species: finless porpoises (Neophocaena phocaenoides), harbor porpoises (Phocoena phocoena), and Dall's porpoises (Phocoenoides dalli). The porpoises were found stranded or were bycaught along the Japanese coast. Concentrations of OH-PCB were the highest in Dall's porpoises (58pgg(-1) wet wt), second highest in finless porpoises (20pgg(-1) wet wt), and lowest in harbor porpoises (8.