Posted in Science and other Hands On activities

Today Kelly from the Quinsam Fish Hatchery that we had just visited a couple of weeks ago for a field trip was able to come out to one of the mom's houses and have the kids participate in the dissection of a Coho. She is extremely knowledgeable on the subject so it was a great learning experience for K : )

 

 

Once you have removed the gill covering on the outside of the fish you can easily get to the gills beneath and remove them. This is a photo of one up close. They are really quite stiff and the spikes on the gill are like little rakes. So when the fish takes in a bug or something to eat it isn't flushed back out the gills. These little rakes hang onto the food and keep it so that it can be digested. Once the gill was removed from the fish you can easily put your finger inside the opening and into the fish and pop out his eyeball. After doing this the children got to cut open the eye and remove the lens to have a look at. It is like a tiny little ball, much smaller than the cow's eyeball that I dissected when I was in school : )

 

 

Here Kelly is opening up the fish so that everyone can have a look inside. The pink part that you can see right inside the opening in the fishes belly is the milt sack. She continued taking out parts such as the liver, heart, digestive tract, spleen and so on and quizzing the children on what each function they performed within the body.

 

 

This is the swim bladder. If you pinch off the end when you remove it from inside the fish you can actually keep the air inside it which makes it look like a balloon. Do you know what the swim bladder would be for? This is a sac that holds air that the fish sucks into it and helps it to float higher in the water. So the more air it sucks into the swim bladder the higher the fish can float and of course the less air in it the closer to the bottom of the river or ocean the fish can swim. 

 

 

K got a little light headed through part of the dissection and ended up having to sit with his head between his knees. Poor guy. He really doesn't like to see blood and guts or even talk about it because it makes him feel queasy so I was really proud of him when he helped to cut open the underside on one of the coho when the children were aloud to work on their own fish.

 

Did you know that you are never supposed to handle a fish by his tail? If you catch a fish and he hangs from his tail and thrashes about as he tries to get away it actually causes the vertebrae in his back to separated and cause him to have back problems. Kelly held one of the fish by its tail and pulled downward to simulate what it would be like if the fish were thrashing downwards and we got to hear what the spine separating sounded like. It's like someone cracking all of their knuckles at the same time. Ew, sort of gross sounding if you ask me : )

 

The kids loved it though. Especially when they got to investigate the fish on their own!

 

Blessings,

BChsMamaof3