Respiratory Microbiome of Endangered Southern Resident Killer Whales and Microbiota of Surrounding Sea Surface Microlayer in the Eastern North Pacific

Abstract

In the Salish Sea, the endangered Southern Resident Killer Whale (SRKW) is a high trophic indicator of ecosystem health. Three major threats have been identified for this population: reduced prey availability, anthropogenic contaminants, and marine vessel disturbances. These perturbations can culminate in significant morbidity and mortality, usually associated with secondary infections that have a predilection to the respiratory system. To characterize the composition of the respiratory microbiota and identify recognized pathogens of SRKW, exhaled breath samples were collected between 2006–2009 and analyzed for bacteria, fungi and viruses using (1) culture-dependent, targeted PCR-based methodologies and (2) taxonomically broad, non-culture dependent PCR-based methodologies. Results were compared with sea surface microlayer (SML) samples to characterize the respective microbial constituents. An array of bacteria and fungi in breath and SML samples were identified, as well as microorganisms that exhibited resistance to multiple antimicrobial agents. The SML microbes and respiratory microbiota carry a pathogenic risk which we propose as an additional, fourth putative stressor (pathogens), which may adversely impact the endangered SRKW population.

An Economical Custom-Built Drone for Assessing Whale Health

“…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). Bacteria from the Streptococcus genus is common in mucous membranes of animals (and humans) and is known to be found in the upper respiratory tract (Krzyściak et al, 2013).…”

“…Bacillus sp. was also identified via blow collection from western North Pacific gray whales and Southern resident killer whales (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.…”

“…Early approaches to sampling whale blow involved passing a cotton gauze or nylon stocking on the end of a carbon fiber pole through the blow when the animal surfaced (Hogg et al, 2009;Hunt et al, 2014). Recent advancements on this method have seen the use of a pole with a number of petri dishes with lids to sample wild killer whales (Raverty et al, 2017). However, this method requires extremely close vessel approaches to whales (Hogg et al, 2009).…”

Genetic and genomic monitoring with minimally invasive sampling methods

“…that antibiotic resistant bacteria were present in the respiratory microbiome of apparently healthy individuals (Raverty et al, 2017). Therefore, microbiomes could be regularly screened using MIS for the presence of both beneficial and harmful components as part of an ongoing genetic monitoring scheme.…”