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Saturday, September 12, 2015

August 28th: Last Official OBI Encounter of the Season

As August came to a close, it was about time for my research partner Michael to head back to start his senior year at Reed College....but not before one final whale encounter! It happened out at Lime Kiln as J- and K-Pods went north in spread out groups, our 59th research encounter of the summer.

J41 Eclipse

J47 Notch
J27 Blackberry and J46 Star

From left to right J27 Blackberry, J31 Tsuchi, J28 Polaris, and J46 Star

At the end of the passby, some of the K13s were north and some were south of Lime Kiln. The pods have been splitting into smaller and constantly changing groups over the last few years, but it's still highly unusual for a matriline to split, so we figured one of he partial groups of the K13s would go join up with the other. Indeed, that's what happened - though it took K20 Spock going back south to round up the rest of her family! She went down there, got them, and then they all came back north.

Spock detours back south to get the rest of her family

While I'll still continue to collect some behavioral data as I have whale encounters throughout the year, this marked somewhat of an ending of our first field season at the Orca Behavior Institute. It's worth taking a little time to reflect on all the data we collected this year - much more than I think either of us hoped for! 

Our 59 research encounters resulted in over 91 hours of behavioral observations and 129 hydrophone recordings totaling more than 38 hours. Surprisingly, K-Pod was present for more of our encounters (47) than J-Pod (46), though our most encountered matriline was the J19s (present for 38 encounters).

Here's how our 91 hours of behavioral observations parsed out in terms of which pod or pods were present:

It seems to be making less sense to look at socialization in Southern Residents in terms of pods, however, as pods aren't as stable as they were when studies began 40 years ago. Instead, matrilines seems to be the most stable social unit. Here's how our data collection for the summer breaks out by matriline, showing which family groups we spent the most and least time with. J-Pod families are in blue, K-Pod in yellow, and L-Pod in red. The two smallest bars, L12+ and L54+, refer to the L12 and L54 sub-groups which are stable units made up of several small matrilines.

Finally, our behavioral observations ranged throughout most of the daylight hours, from before 7:30 AM until after 9:30 PM. Here's how out observations of the Southern Residents broke down by time of day. The peak observation hour ended up being between 5 and 6 PM:

Much more advanced analysis will be happening over the coming months as Michael works on his senior thesis, but for now I thought this was an interesting overview of who we spent time with this summer. Stay tuned for much more from the Orca Behavior Institute, and in the meantime, my whale encounters certainly haven't come to a stop!

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