Since 1976, the Center for Whale Research has been conducting observation-based studies of killer whales in the Salish Sea. The unique dataset produced by this work has informed conservation efforts in both the USA and Canada and helped us understand these animals’ complex lives, revealing factors that influence survival, reproduction, social structure, and the evolution of this species unique life-history. Our research has established that a lack of salmon is the major factor constraining the recovery of the population. However, we still have many gaps in our knowledge.

 

Indeed the most recent NOAA/NMFS Priority Report for the SRKW in 2015 outlined two priority questions for future research:

1) What is causing decreased SRKW reproduction? 

2) What is causing increased SRKW mortality? 

 

Understanding individual and group (social) behavior is key to answering both of these questions. Our research objective for the UAV activities will directly address this knowledge gap by recording how individual behavior and the behavior of social groups relate to survival and reproductive success.

 

Nearly all our knowledge of Southern Resident killer whale behavior is based off surface observations, from boats, and from shore. However, killer whales spend nearly all their time submerged and out of sight. This means that we have not been able to document most of these whales’ lives in any detail. Using a UAV gives us the opportunity to get above the whales and look down into their world. We can position our drone, a DJI Matrice 600, hundreds of feet above the whales, and monitor their movements and behaviors as they move through their own world without interfering in their activity. Under the right conditions, the UAV can see to a depth of 10 meters underwater and a lot of behavior happens in this surface zone.

 

This summer has already seen several successful drone flights, documenting a variety of behaviors, from food searching to coordinated travel and foraging, to socializing. This data will help us to understand better social behavior and its consequences in this population, as well as foraging strategies and foraging efficiency and how this relates to survival and reproduction. With this information, we will be able to make future predictions for the health and survival of these amazing animals and inform strategies to recover this endangered population.

 

Spotlight on the UAV

The DJI Matrice 600 Pro was specifically chosen for this research because of its high reliability. It has six redundant batteries; six actively cooled motors; engine-out return-to-land capability; automatic return-to-land capability in the event of the loss of radio-signal; a triple redundant flight control system with diagnostic algorithms to compare sensor data from the three Global Navigation Satellite System units in real-time; a sine-wave driven electronic speed control for improved accuracy, reliability and safety; and real-time monitoring of aircraft position and all critical aircraft systems via telemetry downlink. The UAV was funded by donations to a crowdfunding campaign, and we are exceptionally grateful to everyone who supported this.

 

What about disturbance to the whales?

The UAV is a non-invasive method for recording behavior, and there is very little potential for noise disturbance to the SRKW. Recent work has shown that the noise produced by UAVs couples poorly into the water, and could only be quantified above the background noise of the recording sites at one-meter depth when flying at altitudes below 10 meters. All of our flights are conducted well above this height (typically 60 meters), and it is likely that the whales are not even aware of the presence of the UAV during our research flights.