What is the project about?
Lots of things to do with salmon and the waters they live in! By the end of the project you will know so many interesting things about them that you can tell your family and friends. One of the main things you will have learnt is how to care for and rear salmon eggs in your school until they are old enough to be returned to a suitable river or burn.
What does the project involve?
Every project may be run slightly differently depending on local circumstances.
In most cases, you will be visited by an expert and given an interesting illustrated talk. The expert will tell you all about salmon with emphasis on their lifecycle, needs and threats. They will also tell you about ways that we can protect salmon and the environment in which they live.
At the same time or soon after you will be given a specialised hatchery tank and up to 100 eyed salmon eggs to care for in the school which you will raise for a few weeks until they are big enough to be released. You may also go for a fascinating trip around other places associated with what you have learnt such as other larger hatcheries, fish farms or even a smokehouse! You will also get a chance to check up on your fish months after they have been released by electrofishing your release site.
QUESTION: Can you think of any ways that you could remove any dead eggs or alevins?The most important part of the whole project is looking after your salmon eggs. The expert who visits you will provide the necessary equipment and go through all the main things you need. To help you remember we have listed below a few key things:
Hatchery Tank - you will be provided with a suitable tank for rearing your fish in. There are a number of different designs, some have only one tank whilst others have two tanks linked by pipes - all will do the job!
Salmon Eggs - you will be provided with about 100 eyed eggs which will be close to hatching. You will be able to see the eyes of the alevins inside the eggs. If you look closely they may even move their whole bodies! It will be important to consider what the eggs should be placed upon in the tanks as they need water to circulate around them. You could use metal grids or gravel from a nearby river.
Water - you will obviously need water around the eggs! You must not use tap water though as it may contain chemicals which, although good for people, can be deadly for fish. Make sure though that the river or burn that your teacher collects the water from is clean and unpolluted. Water may also leak or evaporate from your tank so keep a store of water to top up water levels when necessary.
Water Temperature- the eggs in the river will experience cold temperatures throughout the winter and spring. It is important to try to keep conditions within your hatchery as natural as possible so it is crucial to keep water temperatures low. Due to the heating in your school, if the water in the tank was left it would heat up until it was too warm and the eggs would die. You must monitor the water temperature using a thermometer to ensure that the water temperature does not exceed 10°c. The different type of tank systems all have different ways to keep the water cool. Some will use ice packs (that you will need to freeze) placed in a second tank and a water pump is used to pump the cold water to the other tank containing the eggs. Other systems may have a specialised 'cooler unit' which ensures the water is kept at a constant cool temperature.
Light - again, remember where the eggs would naturally be? When they are hidden deep in the river bed they are always in the dark. Too much light can affect their development so make sure you think of a way to keep the egg tank dark.
Egg Shells - For every egg that hatches there will be an egg shell! If all your eggs hatch there will be a lot of egg shells floating around your tank which could block filters or grids. You will need to clean these to make sure the water can flow freely at all times. Also remember once your eggs hatch, although the alevins will not move very much, as they get older they will swim around and could be sucked into filters or pipes. Too make sure this does happen you will need to put some sort of barrier over these but ensure water can still move around.
Death - some eggs and alevins will probably die, this also happens in nature. A dead egg or alevin will quickly turn totally white when it dies, and remember alevins do not move much when they first hatch and may appear lifeless even though they are healthy! It is important for the hygiene of your hatchery to remove any dead eggs or alevins and you will have to think of ways to do this without harming the surrounding healthy ones.
Feeding the Fish - once hatched the alevins will feed themselves using their yolk sac! Once the yolk sac has nearly been used up it will be time to return them to the wild.
Releasing the Fish - it is one of the most exciting days of the project when you go to release the fish! You will take your fry to the river in a bucket (make sure you remember to put your wellies on!) and gently pour them into the river. It will be important to put them somewhere that they will like to live. The knowledgeable person who has been helping you with your project will be able to show you a good place to put them. You will be surprised to see how quickly they hide away in the rocks and gravel! Now you will leave the fry to go about their business until the summertime when you will come back and electrofish to see them again.
Catching Your Fish - On the day you go and catch your fish again you will go back to the place that you released your fish. To do this, the people delivering your project will use a process called 'Electrofishing'. Electrofishing is quite a magical process that uses electricity in a controlled way to catch the fish.
Make sure you listen to the people who are showing you electrofishing. They will tell you all about the process and will give you important information to do with your safety and the safety of the fish. Make sure you keep out of the water when the biologists are working and never put your hands in the water when the electrofishing equipment is in the water.
QUESTION: Is the river habitat different in these places?Watch the biologists carefully whilst they are working. It's amazing how the fish suddenly appear! The biologists will probably catch other fish as well as salmon in the electrofishing site. They might catch some trout or perhaps an eel! Look and see where the different types of fish come from.
The biologists will put the fish into one bucket whilst they are working but will split the fish they capture between several buckets when they show you the fish so that everyone gets a chance to look. At this point, you will be able to hold the fish and see how they've grown! To make sure that you don't hurt them, only touch the fish when your hands are wet as dry hands make the salmon's skin burn.
Also try to always hold the fish over a bucket when you're looking at them - then if they jump, they land back in the water unharmed!
QUESTION: How long can you see them for?Once you have finished looking at the fish, you will carefully put them back into the river. Watch how quickly they disappear back into the rocks.
