Thursday, July 24, 2014

Isotopes. Stable ones.

It’s not so easy to get to the Amazon, and it’s even harder to get the right permits to collect data in a protected reserve in Peru.
VIVA PERU!!! We happened to be on site for Peruvian Independence Day, which is a Big Deal in Peru (as it should be.) Photo by Greta
But in general, in life, I operate under the assumption that I may not pass this way again, and so I try my hardest to make the most of a situation, no matter what.  Since most of the hard logistical stuff had already been worked out by the folks running the show here, I thought I’d seize the opportunity and gather as much data as I could this summer while simultaneously pretending to be on vacation.
As an end-of-the-summer-treat, we had the great pleasure of participating in the first-ever PV2 Olympics. Despite our best efforts and intentions, and due to a very unfortunate translation debacle, what should have been a Canoe Dream Team (Nico, Ellen, Samwell) resulted in a disappointing loss. In order, those are the faces of "WE COULD HAVE WON," "Meh...yay for trying," and "We were racing?" 
As I type, things are still a bit in flux (the lack of interwebs makes it difficult to get in touch with folks in the Know…), but the wheels are in motion and I got the initial clearance to use inevitable gill net mortality for the advancement of science.
Other fish mortalities were NOT used for the advancement of science; instead we smoked them on a palm-frond barbeque that was delicious. In unrelated news, at 5' 8", I am a giant in Peru.
Thanks to all our previous work on Lake Tanganyika, my brain automatically thinks in terms of food web relationships whenever I enter a new ecosystem. And so in the 11th hour (literally hours before I left for Peru), Pete and I set to fleshing out the details of how I could use the gillnet catches to amass a muscle tissue sample set for stable isotope analysis.
There are some armored-catfish surprises here and there, so we have THAT to look forward to (there are quite a few different species of carachama, though they all look pretty much the same, dead, in a bowl of broth, looking back at you...)
When I first arrived, all was easy. The water levels were near-peak (but falling), fish were living it up (eating, having babies) in the flooded forest, and diversity was high. Interested onlookers offered to help with fish dissections and take photos of each sample or write in my log book when my hands were too bloody or slimy to hold the pencil. And since it’s my secret mission to educate the world on the incredible properties (and existence) of otoliths, others watched in awe and horror as I picked around brain tissue to find those precious stones (completely unrelated to current scientific pursuits, but since we were already in there…). I measured gut lengths and rummaged through stomach contents to get a sense of trophic position and recent diet, and (most importantly), I got that tiny piece of muscle tissue so we can (hopefully) reconstruct the food web. 
One of my favorite things to do is go set/retrieve the gillnets with the Peruvian guides. Euclides and I made our way into water lettuce heaven one day, but all we really caught was wolf fish (yawn).
And then everything changed.

The water has come down about 20 feet since I first arrived.
It's kind of hard to appreciate the depth change until you need to get back on the boat from shore. Then Shit Get's Real...
Instead of motoring up to the lake and parking the boat in the forest, we’re suddenly in danger of grounding the boat. The lake I assumed to be a permanent park fixture will dry up completely in the coming months. Instead of 40 or so fish of moderate diversity, we started catching LOTS (hundreds) of ONE species of fish (local name carachama, the once-endearing armored catfish). They’re common aquarium fish in the US since they eat algae.
This has become our go-to fishing spot, and our days here are numbered as well. Here, Pool's on a quest to retrieve a piranha that feel between the floorboards (a common problem in our world).
I usually leave the net-emptying to the experts, but on that particular day I offered to help Euclides (who was giggling like a little kid at catching so many fish) since we were running out of daylight. A thousand tiny cuts ensued, but I think I gained some street cred in the process. Carachama soup is a delicacy here, so we kept some for dinner. I think I expected chunks of meat in some kind of broth, but instead I was presented a bowl full of broth and a giant fish staring back at me.
Death by a thousand cuts. It probably saved us at least 30 minutes when I joined the remove-carachama-from-the-gillnet quest, but there were consequences...
"Mmmm...." (stifles gag reflex...)
I’m not sure how this will play out for my research purposes, but I still have 2 weeks to go. Here’s hoping. 
Even under the worst of circumstances, it's hard to get too worked up when you have sunsets like this on a nightly basis. (I think Mario took this picture)
[UPDATE! and not a good one. My boss says the food web probably isn't "complete enough" to be "useful" (I'm struggling to remember why I work for this person...). Plus they samples in question are still technically stuck in Peru since I don't have the permits in place yet. Ho hum. Yay for trying??]


  1. I always wondered what they made those armored catfish into. It was always kindof horrifying to see them in the market with all their fins hacked off with a machete and still alive despite being out of water for a long time. They must be pretty resilient buggers.

    1. It's *shocking* how long they could be of water. But fear not: they are highly prized (and fought-over) soup meat, and nothing really goes to waste! On an unrelated note, I think armored catfish are my spirit animal ;).

  2. So sorry to hear about the food web! Would it be possible to get all of the samples back and put it together and reevaluate then? I feel like I have often heard the same thing from advisors and occasionally have been able to come back with a stronger and more complete argument for why we should keep working on something.

  3. I'm still working on it. A good friend of mine (Pool!) is keeping them for me until I can get the right permits. The red tape sucks, but I guess it exists for a reason...