What We Do in Alaska in the Winter: Rockfish Party!

by buzzbizz | Mar 25, 2014 | Uncategorized

February 21, 2014
by Molly Zaleski

It's a rockfish party up here in Juneau! We're bioprocessing young of the year (YOY) rockfish that were collected in 2013. What does 'bioprocessing' mean? It means we've taken fin clips from them so that a partnering lab can identify if they're Pacific Ocean perch or a different kind of rockfish. We've also taken tissue samples from some to measure their RNA/DNA ratios. On top of that, we removed their stomach contents so that we can get a snapshot of what these little fellows have eaten. This can be pretty difficult because, while most of them have been frozen nicely and look like this:

Some of them have been squished in the transfer from the Gulf of Alaska to Juneau and look like this:

But we've got a crack team on the job to pull the stomach contents proficiently! Shout-outs to our contractor team: Wess Strasburger, Casey Debenham, Hannah Findlay, Tayler Jarvis, and Eamon Conheady.

Finally, they rockfish are dried (to calculate how much of their bodies are tissue versus moisture), and then processed for their chemical components: energy, lipids, ash, and protein. The energy is calculated through bomb calorimetry which is a really fun way of saying we blow them up and calculate the resulting energy from their fish-splosion!

It's a lot of information from some very tiny fish! And while it's fun working with the rockfish, we've noticed, anecdotally, that their eyes seem to be the last things that grind up when we try to homogenize the fish into a fine powder, which leaves me with the Rockwell hit, “Somebody's Watching Me” stuck in my head. If it's now stuck in your head, you're welcome! 

Map Matters

by buzzbizz | Mar 10, 2014 | Uncategorized

Habitat maps are a useful tool to fisheries researchers and assessors but are not often available for a large scale project.  Jodi Pirtle, a postdoc working for the Gulf of Alaska project, applies her seafloor mapping skill set to the Gulf of Alaska Integrated Ecosystem project to provide information on habitat.

Born and raised in Cordova, Alaska, Pirtle finds a lot of meaning in the work she is contributing to the project. “I've been thinking about this stuff my whole life,” she says.  In the effort to better understand five species of commercially caught fish, Pirtle has been overlaying fisheries survey data on high resolution seafloor maps to get a better idea of the habitat preference of different fish. 

“It's landscape modeling which has been going on a long time on land, now applied to the ocean,” says Pirtle who works at the NOAA Auke Bay Lab in Juneau.  “We are taking GIS data of all kinds – kelp beds, geology, seafloor terrain – and merging that with fisheries survey data to generate habitat suitability models and maps.”  This kind of work has gone on on a small scale throughout the Gulf but this is the first large scale Gulf wide project of its kind.