Prevalence and Abundance of Cyamid “Whale Lice” (<i>Cyamus ceti</i>) on Subsistence Harvested Bowhead Whales (<i>Balaena mysticetus</i>)

Abstract

We present findings on the prevalence and abundance of cyamid ectoparasites (Cyamus ceti) or “whale lice” on bowhead whales (Balaena mysticetus) harvested for subsistence in the Bering, Chukchi, and Beaufort Seas from 1973 to 2015. Cyamids were present on 20% of the 673 whales that were examined for cyamid ectoparasites. Logistic regression was used to determine factors associated with cyamid prevalence. The probability of cyamid presence increased with age, length, and improving body condition, but decreased over the past 35 years. Cyamid presence was also more probable on whales harvested in the spring than on those harvested in the fall. When present, cyamid abundance was typically low(&lt; 10 per whale). Case histories provide ancillary information about the relationships between abundance of cyamids and their bowhead hosts. Environmental change and increasing anthropogenic disturbances are expected to occur in the Arctic regions inhabited by bowheads. We recommend continued monitoring of subsistence harvested whales for cyamids, as well as further investigations into the roles of environmental and anthropogenic variables in cyamid prevalence and abundance, as part of a comprehensive program of Arctic ecosystem assessment.

Evidence of molting and the function of “rock-nosing” behavior in bowhead whales in the eastern Canadian Arctic

“…There are biological factors affecting skin condition that may explain why bowhead whales molt. One is that they may slough their skin to shed ectoparasites such as cyamids (i.e., whale lice) [ 42 , 43 ] and accumulated diatoms (i.e., phytoplankton) [ 44 ] that may damage their epidermis and potentially impede thermoregulation. Another possibility is that bowhead whales are shedding solar damaged skin [ 45 ].…”

Whale lice (Isocyamus deltobranchium & Isocyamus delphinii; Cyamidae) prevalence in odontocetes off the German and Dutch coasts – morphological and molecular characterization and health implications

“…So far, mostly opportunistic findings were reported, describing cyamid infections on harbour porpoises and a white-beaked dolphin from the North Sea ( Stock, 1973a ; Fransen and Smeenk 1991 ; Lehnert et al, 2007 ), but also from more rarely observed visitors like a Northern bottlenose whale ( Hyperoodon ampullatus ) and a sperm whale ( Physeter macrocephalus ) ( Stock, 1973b ). Few systematic surveys on whale lice have been performed worldwide, e.g., for odontocetes on I. delphinii on pilot whales off the Faroe Islands ( Balbuena andRaga, 1991 ), and Syncyamus aequus on striped dolphins in the Mediterranean ( Fraija-Fernández et al 2017 ) and for baleen whales on Cyamus ceti on bowhead whales ( Baleana mysticetus ) ( Von Duyke et al, 2016 ), on C. boopis on humpback whales ( Megaptera novaeangliae ) ( Iwasa-Arai et al, 2018 ) and on C. ceti , C. kessleri and C. scammoni on gray whales ( Callahan, 2008 ). Whale lice prevalence in the present study was low compared to other commonly occurring parasite species in harbour porpoises in the North Sea, like gastric and lung nematodes (30–90%), or hepatic trematodes (50%, Lehnert et al, 2005 ).…”

“…Whale lice prevalence in the present study was low compared to other commonly occurring parasite species in harbour porpoises in the North Sea, like gastric and lung nematodes (30–90%), or hepatic trematodes (50%, Lehnert et al, 2005 ). For odontocetes, whale lice prevalence of 27% on striped dolphins in the Mediterranean ( Fraija‐Fernández et al, 2017 ), and 30% on Faroe Island pilot whales ( Balbuena and Raga, 1991 ) have been reported and for baleen whales a prevalence of 20% was for bowhead whales from the Bering, Chukchi, and Beaufort Seas ( Von Duyke et al, 2016 ). A striking difference in whale lice prevalence was found between the harbour porpoises stranded in the Netherlands and those stranded on the German coastline, with a lower prevalence observed in Germany (1.6%) compared to the Netherlands (7.6%) in this study.…”

“…In general, lower intensities on odontocetes ( Fraija‐Fernández et al, 2017 ) were observed compared to mysticetes, where high loads of whale lice are reported ( Leung, 1965 ; Rice and Wolman, 1971 ; Takeda and Ogino, 2005 ). Low intensities on smooth-surfaced bowhead whales ( Von Duyke et al, 2016 ) and high intensities on right whales ( Eubalaena glacialis ) with lesions ( Kaliszewska et al, 2005 ) were found, reflecting the necessity for these ectoparasites to find suitable sheltered microhabitats on their hosts.…”

Diseases and parasites

“…Since cyamids have no free-swimming stage, infection depends on direct physical contact between whales. Cyamid prevalence and body burden of BCB bowhead whales is around 20% with an average body burden of 1–5 whale lice ( Von Duyke et al, 2016 ). Heavy cyamid infestations (~50–100 cyamids) are uncommon, but have been observed in bowhead whales entangled in fishing gear, bowhead whales with old entanglement injuries, and previously harpooned bowhead whales.…”