FYI

Abstract

Aerial surveys are frequently used to estimate the abundance of marine mammals, but their accuracy is dependent upon obtaining a measure of the availability of animals to visual detection. Existing methods for characterizing availability have limitations and do not necessarily reflect true availability. Here, we present a method of using small, vessel-launched, multi-rotor Unoccupied Aerial Vehicles (UAVs, or drones) to collect video of dolphins to characterize availability and investigate error surrounding group size estimates. We collected over 20 h of aerial video of dive-surfacing behaviour across 32 encounters with Australian humpback dolphins Sousa sahulensis off north-western Australia. Mean surfacing and dive periods were 7.85 sec (se = 0.26) and 39.27 sec (se = 1.31) respectively. Dolphin encounters were split into 56 focal follows of consistent group composition to which example approaches to estimating availability were applied. Non-instantaneous availability estimates, assuming a 7 sec observation window, ranged between 0.22 and 0.88, with a mean availability of 0.46 (CV = 0.34). Availability tended to increase with increasing group size. We found a downward bias in group size estimation, with true group size typically one individual more than would have been estimated by a human observer during a standard aerial survey. The variability of availability estimates between focal follows highlights the importance of sampling across a variety of group sizes, compositions and environmental conditions. Through data re-sampling exercises, we explored the influence of sample size on availability estimates and their precision, with results providing an indication of target sample sizes to minimize bias in future research. We show that UAVs can provide an effective and relatively inexpensive method of characterizing dolphin availability with several advantages over existing approaches. The example estimates obtained for humpback dolphins are within the range of values obtained for other shallow-water, small cetaceans, and will directly inform a government-run program of aerial surveys in the region.

     Take care and be safe!

Aloha and Drone On!

Perhaps you could provide a translation in laymans' terms.

Maybe show an example.

Sean-bumble-bee Posted at 1-31 04:40
Perhaps you could provide a translation in laymans' terms.

Aloha Sean,

     This is an update on how drones are impacting whale and dolphin research in a very positive way.  Some of the technical details are provided.  Basically, this is a "good news" story.

     We have researchers who frequent this Forum and they are interested in how drones can help them in their research.   We have had exchanges that they found useful.

     Take care and be safe!

Aloha and Drone On!

DAFlys Posted at 1-31 05:14
Maybe show an example.

Aloha Flys,

     This forum regularly has examples of the basic form of observation noted in this research abstract.  You are on this forum so much, that I would venture a guess that you may find an example in the month of February (even though it is the shortest month!).  

     Drones are impacting our lives in really good ways and those examples should be noted.  Maybe you can contribute in that effort by helping note this type of observation?

     Take care and be safe!

Aloha and Drone On!

That was a little too much for me to absorb on one reading but it's good to see drones helping out with research like that.

Prairie Chicken Posted at 2-1 11:37
That was a little too much for me to absorb on one reading but it's good to see drones helping out with research like that.

Aloha PC,

     Yes, very much so!  State of the art scientific research using state of the art DJI drones like we use recreationally, but they use it for science.  When we see an aspiring youngster with drone skills and we live in an area near a research center, we should be able to make the connection and suggest for the kid to see if the research center needs drone help.  Who knows, maybe the kid might get a degree through the research center and the center might solve research issues through the kid's skills?  Sounds good to me!

     Take care and be safe!

Aloha and Drone On!

Cetacean Posted at 2-1 14:03
Aloha PC,

     Yes, very much so!  State of the art scientific research using state of the art DJI drones like we use recreationally, but they use it for science.  When we see an aspiring youngster with drone skills and we live in an area near a research center, we should be able to make the connection and suggest for the kid to see if the research center needs drone help.  Who knows, maybe the kid might get a degree through the research center and the center might solve research issues through the kid's skills?  Sounds good to me!

Best of luck with it. I hope it works out.

Prairie Chicken Posted at 2-6 08:12
Best of luck with it. I hope it works out.

Aloha PC,

     Actually, this abstract post was from MARMAM, a marine mammal discussion group.  I pull from that group when it is useful elsewhere like with this forum.  I am way too old to be out on the water doing other than holding on for dear life!  Mahalo for the good wish though!

     Take care and be safe!

Aloha and Drone On!

Sounds like they have a whale of a time using drones for good porpoises. Best of luck to them.

Prairie Chicken Posted at 2-7 03:25
Sounds like they have a whale of a time using drones for good porpoises. Best of luck to them.

Aloha PC,

     LOL!!!  Very apropos!

     Take care and be safe!

Aloha and Drone On!