Snowshoe hares
Tomorrow I'm mailing my camera back to Cuddeback to be fixed or replaced. It's aggravating because I have bears and moose and lynx and wolves literally running through my backyard and I want to see them!
Anyway, what this post is actually about is the dissection of pink salmon (humpies) that I was able to participate in with local K-4th graders.
**WARNING**
This is another gory posting!
These salmon were collected by the state of Alaska (Alaska Department of Fish and Game, like the NYSDEC), and deemed for whatever reason for educational use only. So Cheryl (Fish Biologist who specializes in Conservation and Outreach) and I packed up 12 salmon, dissection equipment and headed for a local school. K-12 students have been out for summer vacation since before Memorial Day here, so the students we were working with were in a summer school program.
Our setup...a nice mild breezy day outside is always nice for a fish dissection!
A female pink salmon
First Cheryl or I would cut the fish down the belly from right under the gills to the vent...this was before the kids came outside. The dissection was done by hand, once we slit the fish open.
Inside a female...check out the eggs! I think I was more excited than some of the kids. They've grown up cleaning salmon, but I've never experiences it. Way cool!
Eggs or roe
On the left: liver
On the right: Milt sacs (sperm)
Stomach and small/large intestines
Heart
Swim bladder...the fish can control how much/little air is in this organ to move it through the water column! So cool to see...and we were able to pull this one out and look at it. It looked like a balloon..to the kids, haha!
Swim bladder
And NOW for a bit of education :)
Anadromous: a fish (salmon specificall) that is born into freshwater, migrates to salt water where it spends the majority of its life, and swims a final migration back to its birthplace in freshwater where it will spawn, and then die.
These fish will undergo a secondary sexual morph when they re-enter freshwater for the final stage of life. Often in the ocean, they pretty much look like silvery fish...individual species are identifiable, but they look very similar. But when they start to move upstream, they take on color changes and even the males will turn into montrous looking creatures. Below are pictures of some physical changes the pinks go through.
Female pink: not sure of the changes she goes through on the outside. Due to my minimal knowledge of salmon and fish in general, I think that this is what she will probably look like her whole life.
The males on the other hand, will at one point, look similar to the female above. But once they hit the freshwater they start to morph. They will often "darken" in color: taken on a pinkish hue and some watermarking. I hope to have examples of this later in the season with FRESH fish...these were all frozen. But I think the most marked change is that face. They will develop a kype, which is a pronounced curvature of the jaw. It, I suppose, is supposed to look "sexy" to the ladies. The teeth develop more and lengthen, although once the salmon hit freshwater they stop eating. The pink salmon males will also develop this huge hump on the back posterior to the dorsal fin. This one didn't really have one- I think he was taken early in the spawning season. Below is a picture of what they will eventually look like.
That was a really fun day with the kids. I love doing that stuff, not only working with children, but dissections are great! They can be gross (I did have to walk away at one point, after watching a kid gouge out the eyes with his bare hands), but such a great learning experience. I think I got just as much out of it as they did!
Wooo! 100 posts, that is quite the feat. There are so many eggs!!!! Is working with these kids anything like our camp? :)
ReplyDeleteCongratulations on 100 posts!
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