Friday, July 26, 2013

Fish Rodeo

It’s all fun and games…

until someone wrecks their right ear by  diving too deep hunting clams and can’t equalize because of a sinus infection.   

I’ll back up.

Last summer, we collected 4 species of fish along with some clams and snails at each of our 12 survey sites, cut out a little piece of their muscle, and prepped the dry, ground powder for stable isotope analysis. It basically tells us who’s eating what (or whom, as the case may be) in the lake, and based on those data, it would appear that the food chain is getting shorter (gasp!).
A Perissodus, one of our target species! Their foraging strategy is to EAT SCALES OFF OTHER FISH (what the what!), so they (usually) manage to catch themselves in the net when they prey on other net-victims.
To convince ourselves that it’s real, we’re re-doing the entire survey this summer. Pete has years of experience wrangling fish, but I’m new to this game and have marginal (at best) skills to bring to the team. To date, I’ve only caught one Lepidiolamprologus (!), and Pete has captured the other 83 fish solo (I’m such a failure!). But since we still have 5 sites to go, I’m counting on the chance to improve my stats in the 11th hour.
Pete, doing what he does
My supposed contribution was to collect the clams and snails, and usually this isn’t too hard since even in my ineptitude, I’m brilliant at hunting things that don’t move too fast or too much.  But clams were hard to come by at certain sites, and I ended up freediving a bit deeper than I’m (apparently) capable of going. The clotty blood in my spit was a sign that all was not well up in my sinuses. That, and the fact that it felt like someone was stabbing me in the ear with a sharp object every time I went under.
It's no big deal when they're nice and shallow, but that's not always the case.
Luckily my far-sighted teammates were ready for such an event, so I’ve been bumming ear meds from buddies and trying to keep my face out of the water in the meantime. 

Fish rodeo days get kind of long, especially when most of the cutting and tagging occurs after dinner. We’re pickling these guys and bringing them back to the States with us, so if you want to see them up close and personal, come to the Zoology Museum in Madison this fall! 
Since death by hammer awaits my unlucky victims, these clams have good reason to remain evasive.
As for the food chain question, we won’t have stable isotope data in hand for quite awhile...but it would appear that big changes have occurred in this lake in the past 10 years. Stay tuned.

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