A novel non‐invasive tool for disease surveillance of free‐ranging whales and its relevance to conservation programs

Abstract

The numbers of potentially pathogenic microorganisms that have been isolated from stranded cetaceans in the last three decades underscore the urgent need for methods of detection of microorganisms that might cause significant disease and increase the likelihood of population declines. We have designed and implemented two non-invasive techniques for the collection of exhaled breath condensate (blow) from free-ranging whales and demonstrated their suitability for the detection of respiratory bacteria. We successfully collected 22 individual blow samples from eight cetacean species. Using well-established molecular techniques we detected three bacterial genera (Haemophilus, Streptococcus and Staphylococcus). Haemophilus spp. was detected in fin whale Balaenoptera physalus, sperm whale Physeter macrocephalus, humpback whale Megaptera novaeangliae and gray whale Eschrichtius robustus blows, while unidentified b-hemolytic streptococci and Staphylococcus aureus were detected in gray whale and blue whale Balaenoptera musculus blows. The detection limit of the test was determined as 1 CFU mL À1 . None of the identified bacteria were found in environmental (control) samples, suggesting that their presence in the blows was genuine and not due to inadvertent contamination. While the population-level relevance of these bacteria is as yet unclear and it is possible that they are commensal microorganisms, S. aureus has been identified previously as a high-risk pathogen to cetacean health, and streptococci have increasingly been associated with cetacean mortality events. We suggest that future cetacean monitoring programs of vulnerable or threatened species include blow sampling as a means to determine the prevalence of the respiratory bacteria in the populations and monitor spatiotemporal fluctuations as indicators of changes in cetacean health.

An Economical Custom-Built Drone for Assessing Whale Health

“…Due to the infancy of sampling whale breath as an assessment of whale health (AcevedoWhitehouse et al, 2010;Hunt et al, 2013), it is not clear as to the type of microflora/bacteria species that are considered 'normal' for northward migrating humpback whales off Sydney. Despite this, there are similarities in our collection of bacterial genera from the few studies that have collected blow for the assessment of microbiota (Acevedo-Whitehouse et al, 2010;Denisenko et al, 2012;Hunt et al, 2013). For example, Streptococcus and Staphylococcus genera were detected in our samples and have been detected in the blow of blue whales (Balaenoptera musculus), gray whales (Eschrichtius robustus) and Southern resident killer whales (Acevedo-Whitehouse et al, 2010;Denisenko et al, 2012;Hunt et al, 2013;Raverty et al, 2017).…”

“…Sampling exhaled breath or 'blow' from wild whales may therefore provide a more representative assessment of the health status of individuals because samples can be randomly taken from the population. From a single sample of whale blow, scientists may be able to collect respiratory bacteria, lipids, proteins, DNA and hormones (Hogg et al, 2005(Hogg et al, , 2009Schroeder et al, 2009;Acevedo-Whitehouse et al, 2010;Hunt et al, 2013Hunt et al, , 2014Thompson et al, 2014;Burgess et al, 2016;De Mello and De Oliveira, 2016;Raverty et al, 2017). This information is important for whale conservation, as it can be collected over time to help monitor the recovery of whale populations postwhaling.…”

“…In the marine environment, UAVs are revolutionizing the way marine species can be studied due to their small size, apparent minimal disturbance of wildlife and improved safety for both operators and animals (Nowacek et al, 2016;Fiori et al, 2017). UAVs have been utilized for a wide variety of applications including aerial surveys, monitoring, habitat use, abundance estimates, photogrammetry and biological sampling e.g., whale "blow" (Hogg et al, 2009;Acevedo-Whitehouse et al, 2010;Hodgson et al, 2013;Durban et al, 2015;Pomeroy et al, 2016;Schofield et al, 2017).…”

“…Accordingly, alternative approaches have long been sought. Acevedo-Whitehouse et al (2010) deployed a single-rotor UAV (a remote-controlled helicopter) to sample whale blow. Their study demonstrated the feasibility of the approach but loss of samples from the UAV as it careers through the sea air proved a potential issue as did contamination from airborne particulate not expired by the whale.…”

The marine mammal microbiome: current knowledge and future directions

“…In order to increase existing data on the marine mammal microbiome, logistically feasible, nonor minimally-invasive sampling protocols that are easily reproducible and provide biological material suitable for a range of studies are necessary. For example, respiratory blow can be used to examine host DNA 42 and hormone levels 43,44 as well as respiratory associated microorganisms 19,33,37 , while non-invasively collected fecal samples can be used to study host DNA 45 , prey items 46 and the gut microbiome 22,23 .…”