Thursday, January 21, 2010

Lotsa Lamprey!

Greetings Fish Dish readers! I'm a fish biologist working for the Vancouver Fisheries office and was asked to write a guest blog about some of the work that we do here. Since I'm relatively new to the region, one of the first things that came to mind was when I got to see lamprey out in the field, especially since I'd never seen them before. And let me tell you: They. Are. Cool.

First, we have three species of lamprey in our area: Pacific, river, and western brook. A couple of months ago I tagged along with Jeff and Greg (also from our office, see picture at right) who were testing the efficiency of sampling gear in collecting lamprey. It was wet and rainy out, but lamprey don't care about that - we tromped down into a small creek and set up shop to shock as many lamprey as we could in a short stretch of the water. Don't worry - the electroshocking that we were doing didn't harm any of the lamprey - it momentarily stunned them so that we could get them from the water into a bucket. But geez, were they fast and slippery! They were generally wriggling again before we could get them out of the water and it was a challenge (at least for me) to even net them once the shocker tickled them out of the gravel and towards our nets.

We saw two species on that occasion - Pacific and western brook lamprey. River and Pacific lamprey are anadromous (in this case, they spend a couple years in the ocean then return to freshwater to spawn) and parasitic (they grab on to fish and marine mammals with their round many-toothed mouths and feed until they are full). These guys can get big - up to about 30 inches long when they are adults! Western brook lamprey, on the other hand, spend their entire lives in freshwater and are not parasitic. They stay small (reaching only about 6 inches, max) and filter feed on small bits of plants and animals in the water column, and get this - adults don't generally feed on anything at all! Crazy, huh?

So we pulled A LOT of lamprey out of this little creek - but it is difficult to tell the difference between Pacific and western brook lamprey when they are young (larval lamprey are called ammocoetes, see top picture below). We did catch several macropthalmia (bottom picture below), which are Pacific lamprey that are old enough to migrate to the ocean. They are a bit bigger, and are an amazing silver color - their "snout" kind of reminds me of Snoopy's nose because it is big and blunt.





Metamorphosis occurs shortly after and that's when their oral disc and teeth appear so that they can beef up on all the yummy food in the ocean. But check out the mouth of this larval lamprey (below) - it's not formed into a disc yet, and there are very few teeth.

We also shocked for lamprey on the Willamette River from a boat - the setup was a bit different because the water was much deeper. We didn't catch nearly as many lamprey, but it's always fun to get outside and get our feet wet (but not necessarily our entire bodies, which nearly happened to me when I took a minor fall as I was operating the shocking plate winch. Ooops!!!).

If you'd like to learn more about lamprey in the Pacific northwest, check out the USFWS Pacific Lamprey Conservation Initiative website. If you like these pictures, feel free to use them but please give photo credit to Marci Koski, USFWS. Thanks for reading!

1 comment:

  1. VERY nice pictures. You actually get paid for this?

    ReplyDelete