[MARMAM] Re-emergence of nasal mite H. halichoeri in seals from German waters

[Lehnert-Sobotta, Kristina]

Dear colleagues,
on behalf of my co-authors I´m pleased to share the recent publication of our 
paper in IJP:PAW, which is now online:

Reckendorf, A., Wohlsein, P., Lakemeyer, J., Stokholm, I., von Vietinghoff, V., 
& Lehnert, K. (2019). There and back again – The return of the nasal mite 
Halarachne halichoeri to seals in German waters. International Journal for 
Parasitology: Parasites and Wildlife.

https://www.sciencedirect.com/science/article/pii/S2213224418301871?via%3Dihub


Abstract: The nasal mite Halarachne halichoeri (Acari; Halarachnidae) is 
adapted to live in the marine environment with pinnipeds as its primary host 
and can cause different levels of upper respiratory disease in both harbour 
seals (Phoca vitulina) and grey seals (Halichoerus grypus). Historical reports 
of H. halichoeri occurring in seals from German waters date back to the end of 
the 19th century. However, with the disappearance of the grey seal from German 
waters as a consequence of human over-exploitation, the mite vanished from the 
records and the fauna found in Germany for more than a century. Although a 
stranding network has been monitoring marine mammal health along the German 
coasts since the mid 1980s with extensive post-mortem investigations, this 
study reports the first and subsequent findings of H. halichoeri in grey and 
harbour seals from the North and Baltic Sea from 2014 onwards. The re-emergence 
of this endoparasitic mite in North and Baltic Sea habitats seems to have 
occurred simultaneously with the recolonisation of its primary host, the grey 
seal.  During the course of its recolonisation, it was probably transmitted to 
harbour seals sharing the same haul-out sites. Molecular analyses showed a high 
similarity of rDNA sequences with H. halichoeri collected from sea otters 
(Enhydra lutris) in the USA. However, more thorough analyses of additional gene 
loci are required to fully assess the exchange and diversity of this parasite 
between geographically isolated regions and species.

Kind regards,
Kristina Lehnert





Dr. Kristina Lehnert
Institute for Terrestrial and Aquatic Wildlife Research
University of Veterinary Medicine Hannover, Foundation
Werftstr. 6│25761 Buesum│Germany
Phone +49 (0) 511 856 8171
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[MARMAM] New publication: Evidence of Deep-Sea Interactions between Toothed Whales and Longlines (project OrcaDepred)

[gaetan-gs . richard]

On behalf of my co-author, I am please to announce our new publication: 

Gaëtan Richard , Julien Bonnel, Paul Tixier, John P. Y. Arnould, Anaïs Janc, et 
Christophe Guinet. ( 2019). Evidence of Deep-Sea Interactions between Toothed 
Whales and Longlines. Ambio 


https://doi.org/10.1007/s13280-019-01182-1 

The publication is available from the authors or at the link below: 
https://rdcu.be/bAkAi 

Abstract: 
Toothed whales (odontocetes) feeding on fish caught on hooks in longline 
fisheries is a growing issue worldwide. The substantial impacts that this 
behaviour, called depredation, can have on the fishing economy, fish stocks and 
odontocetes populations, raise a critical need for mitigation solutions to be 
developed. However, information on when, where and how odontocete depredation 
occurs underwater is still limited, especially in demersal longline fisheries 
(fishing gear set on the seafloor). In the present study, we investigated 
depredation by killer whales ( Orcinus orca ) and sperm whales ( Physeter 
macrocephalus ) on demersal longlines in the French Patagonian toothfish 
fishery (Southern Ocean). Using a combination of animal-borne behavioural and 
longline-attached data loggers, we demonstrated that both species are able to 
depredate longlines on the seafloor. This study, therefore, suggests that 
odontocetes whales–longline interaction events at depth may be unrecorded when 
assessing depredation rates from surface observations during hauling phases 
only. This result has implications for the management of fisheries facing 
similar depredation issues as underestimated depredation rates may result in 
unaccounted fish mortality in fish-stock assessments. Therefore, while further 
research should be conducted to assess the extent of deep-sea whale–longline 
interaction events during soaking, the evidence that depredation can occur at 
any time during the whole fishing process as brought out by this study should 
be considered in future developments of mitigation solutions to the issue. 

Best regards, 
Gaëtan RICHARD 
https://www.researchgate.net/profile/Gaetan_Richard3 

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