Things are going just swimmingly at the Mosier School! This is Caitlin Kidder (Class of 2013, Environmental Studies & International Relations major), again bringing you an update from the Mosier School's salmon egg rearing project. Last time I blogged, our salmon were merely eggs, but now they're tiny alevin swimming around their tank! Well, mostly hiding in the rocks at the bottom (as they tend to do in the wild, to hide from predators). But the kids are still loving learning about such fascinating creatures, and we've covered a lot of ground in the past few weeks! We've discussed the salmon lifecycle, which is rather complicated and involves both river and ocean habitats.
(The salmon lifecycle by Barbara Harmon)
We also watched a great collection of videos that Professor Rachel Fink gave me, which showed egg development shot through a microscope in a wide variety of animals. The kids kept insisting I rewind to the frog and fish clips, and they ooh-ed and ahh-ed as individual cells migrated and formed various organs and body systems right in front of their eyes. Also on a microscopic level, we scooped up a few of the alevin one morning and viewed them under the school's dissecting microscope (we didn't actually dissect the salmon, don't worry - the term just means a microscope that has a lower magnification power and is used to look at small organisms in their entirety rather than individual cells!), which is hooked up to a video projector. It was absolutely amazing to see the tiny fish's eyes, skin pigment cells, fins, and gills up close. We asked the students to write about the differences they saw between the fish when they were embryos and now, in the alevin stage. The most noticeable difference is the absence of the yolk sac, which the fish have been using as their main source of nutrients up until now. What will they eat next?
(Photo credit: Flickr)
Brine shrimp, of course! Also known as fairy shrimp or sea monkeys, we have a brine shrimp growing system complete with aerators and lights all set up in the classroom. We even gave one of the alevin we took from the tank briefly a brine shrimp egg while it was under the microscope, and it ate it right up! Hopefully by the end of the week the brine shrimp will be fully grown and the alevin will be ready to gobble them up.
Our next project will be setting up a tank in the classroom to house critters that the students will eventually encounter on their field trip to the Connecticut River, when the salmon are to be released. Tomorrow I'll head to the rivers and lakes on Mount Holyoke's campus and try to collect various insects, bugs, leaf matter, small logs, and other bits and pieces to create a terrarium of sorts in the classroom. It will provide a valuable opportunity for the students to practice using a dichotomous key and field guides to help them practice identifying organisms, as they will do on their field trip. Many of the invertebrates also serve as food for young salmon in the wild (they don't start feeding on more substantial fare until they reach the ocean, usually) so maybe they will eventually serve as dinner for our alevin/soon-to-be fry!
I've been working closely with the classroom's teacher and my mentor, Mrs. Gagnon, to prepare curriculum for the last month or so of school. It's a much larger task than I ever imagined! Trying to integrate guidelines for state testing (the MCAS) into our salmon lessons has meant we've strayed from the topic somewhat at times, but it still brings me great joy to be teaching science to such an enthusiastic eighth graders. I'm really looking forward to the last few weeks I get to spend with this group of fourth graders before I go home for summer vacation, and I can't wait to continue working with Mrs. Gagnon on curriculum that can be used by any teacher in any classroom participating in the Atlantic Salmon Egg Rearing Project (ASERP) after I've graduated from Mount Holyoke and after Mrs. Gagnon's well-deserved retirement. In the mean time, please cross your fingers that our young salmon stay healthy before their impending journey down the Connecticut in just a short time!