The Mighty Sturgeon

Afternoon everyone,
A beautiful afternoon in a beautiful place. Blue herons, river otter, hummingbird, eagles, hawks, fish jumping, common terns and laughing children.
The mighty white sturgeon of the Fraser river was the topic of the day.
To begin with we took a look at a pic of the mighty sturgeon then immediately moved on to play a true or false game. Splitting the children into groups armed with their true/false pack they went to work discussing each statement deciding whether they should choose try or false. When finished we went through the statements, the children moving their statements around to place them in the correct column.We used examples and pics to back up our answers.
Here are a few of the statements,
  1.The white sturgeon has two rows of teeth.
 Answer: False.   The sturgeon has a vacuum like mouth, swallowing their prey whole and using their very strong stomach muscles to crush the food. On the front of their mouth they have BARBELS that contain their taste buds. Using these they can search for their favourite foods.
 2. The sturgeon can grow to 4 metres.
 False, the white sturgeon can grow to 6 metres. We measured this out and the children were very surprised indeed.
 3.The body of the sturgeon is covered in scales.
 False, even though the sturgeon is a fish the have SCUTES that run along the top, sides and belly. We checked out the pics for this                            one.
 4.White sturgeon can live up to a maximum of 50 years old.
 False, the oldest sturgeon recorded was between 150-160 yrs old.
5. Scientists think that sturgeons have been around for 200 million years.
 True, they have survived 2 ice ages in the Fraser.
 The island is situated in an estuary next to a salt marsh. We took a few minutes to discuss the ecology of the marsh and estuary. The white sturgeon can adapt to both salt and fresh water and has been known to head out into the ocean to feed.
The river is full of life under the murky surface and life can be quite full bring to find your place, food, safety from predators. We stood in a circle. Each child chose 2 other children in their minds that they would avoid but stay equal distance between the two.  When I said go with arms spread we began to move trying to find our place in the river. A great discussion followed about the dynamics of the river.
We then took a look at the life cycle of the white sturgeon.
The largest freshwater fish in North America eggs are a 1/4 size of a pea. There were gasps as the children thought that they would at least be the size of a baseball considering their size as an adult. The female carries 400,000 to 4 million eggs. The older she is the more she will carry. Young female sturgeons will spawn every 3-6yrs, older may wait from 6-12 yrs.
 Sturgeons do not make nests like salmon they rely on the rivers currents to bring the milt and egg together. This does not always happen so many eggs rot. The eggs float to the bottom of the river and stick to gravel, rocks or any other hard surface on the river’s bottom. 7 days later they will hatch and are 1cm long with yolk sac still attached. 14 days later they are fry. They lose their sac and will float in the currents to find their own place down river. During their first year they turn into juveniles and grow the pointy scutes. They grow 7cm each time until they reach 120 cm. Sturgeons continue to grow until they die.
The juveniles will float downstream at night to avoid predators. We of course played a game next….
FLOATING FOR YOUR LIFE!
Setting up our river we placed cones periodically to act as safety zones. 3 children acted as currents, 4 were juveniles and I was the predator.
The idea was for the juveniles  to drift downstream using the rocks to hide from the predator while using the currents to propel them forward by spinning around with arms linked. (A safety discussion was had before any currents were let loose as you can imagine.)
No broken bones, a few juveniles survived and lots of laughter!
Off to find a rock for snack and story. Tale of a great white fish written by Maggie de Vries is set in the Fraser river. It’s a timeless tale and beautifully illustrated by Renne Benoit. The children very much enjoyed this tale, all you could hear was the lapping of the river and the odd tarn overhead.
Drawing and labelling next, I was very impressed by the detail and imagination of everyone.
We gathered in the shade ,yes we were actually hot, to go over why the sturgeon is in danger.
The sturgeon had remained virtually unchanged for 65 million years until humans came along and nearly wiped them out in only 100 years.
Over fishing, poaching, pollution, water temperature changes, basically all the usual subjects. The sturgeon are protected by laws that prohibit commercial or private fishing. You can catch them but need to release them straight away, many are injured due to mishandling. Sturgeon roe goes for many hundreds of dollars so poaching is still done along the Fraser.
In 100 years the sturgeon population decreased from hundred of thousands to 4,500 due to overfishing mainly.
We discussed the various problems using examples. Bio accumulation is a major one.
We went off to create a skit involving how sturgeon are affected by bio accumulation due to run off.
Great ideas from the children and a brilliant presentation. Each child had their role-Davis was the current, Jon Hunter the sturgeon, Gabrielle and Nathaniel the insects and Sophia as the pollution, oscars all round I think!
Have a great week everyone,
Lisa

May 09, 2012 | Category: Uncategorized | Comments: none

 


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