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All posts by Mr Pietri
Release day on Sanday
If the islands were bathed in warm sunshine last Wednesday, the weather certainly took a turn for the worse over the week-end and this morning, the prospects of decent weather for release day were unlikely…
However, after dinner, it was mild and the winds were light, and if it hadn’t been for the persistent rain, paddling in the loch, releasing trout would have almost been enjoyable!
Still, it was a relief to see our healthy fry swim away and disappear into the cover of the margins.
A few scoops with a fine mesh net revealed a lot of freshwater shrimps (gammarus) which probably constitute the staple diet of the Bea Loch’s trout population.
In spite of the rather dull weather, it was good to see that it wasn’t just the children who were interested in the peedie troot, but a number of adults also showed interest and joined the group by the banks of the loch: Councillor Clakson, Mr and Mrs Allan and Mr Thorne, the Sanday Ranger, who gave us a little presentation about the species of birds which can be found on or near the loch. He explained to a captive audience that we could, not only see mute swans but also Whooper swans which would soon start their migration to Iceland. Mr Thorne also spoke about the two main species of ducks present on the loch: tufted ducks and widgeon.
Back to the school, the shed was tidied up, the tank and gravel rinsed, all to be ready for the 2015 edition of Troot in the Shed…
Thank you to Mrs. Lennon and Mrs Muir who accompanied the pupils to the loch but also to Irene who checked the tank daily with the pupils and kept a watchful eye on the development of our fry.
Mr P.
The Stronsay alevins swim free…
For the second year in a row, release day on Stronsay couldn’t have happen on a better day! A bright sun was out and the surface of the Meikle Water was more like a sheet of glass…
Mrs Denisson’s class walked down to the bank of the loch and once all the 150 or so small fish had been transferred into small poly bags, it was time to let them swim freely into their new environment which seemed very welcoming on such a gorgeous spring day!.
Our next mission was to try and find out what the newly stocked fry would be feeding on for the next few years: nets, trays and magnifying glasses came out and soon, the pupils were bringing back some very interesting tiny creatures: water beetles, fresh water shrimps, water boatmen (corixa), stone fly larvae, caddis larvae and a type of flatworm (see our photos below).
After a very enjoyable afternoon, with the calls of greylag geese and oyster-catchers in the background, it was time to catch the minibus back to school.
Well done to the Stronsay pupils for carefully looking after the small trout and once more, achieving to bring to fry stage most of the ova (around 95%) the school received back in early February!
Mr P.
Troot in the Shed 2014 update
Hi everybody,
Just a quick update on Troot in the Shed 2014 so far:
- Stromness Primary: The alevins were successfuly released in the Mill Burn last week.
- Sanday School: The alevins are very healthy and have suffered virtually no loss. The release date in Bea Loch is for 17/03.
- Stronsay School: Same situation as on Sanday with a release in the Meikle Water planned for 12/03.
- St. Andrews Primary: There isn’t much left of the alevins’ yolk-sacs and they should be swimming freely in the Burn of Quoykea by 13/03…
- Papdale Halls of Residence: I’ve just received an update from Mr. Cuddihy and their alevins are doing very well but still have a substantial yolk sac, so the release into the Wideford Burn is probably still a couple of weeks away.
- North Walls School: The alevins are healthy and well looked after – Thanks, Olivia, for letting us know!;-)
- Dounby Primary: The release in the Burn of Hourston is scheduled for week starting 13/03.
All these dates, subject to the whims of the Orcadian weather of course…
We’ll keep you posted on the future developments…
Mr P.
Stromness Primary release their fry in the Mill Burn.
Last Thursday, Mr Taylor’s P6 class put on their wellie-boots and headed for the banks of the Mill Burn which runs only a few trout leaps away from their school… What started as a handful of pea-sized orange eggs had turned into very healthy fry, with hardly a hint of a yolk sac left. It must have taken a lot of care and dedication to reach such a successful outcome as the tank temperature at Stromness Primary was in the “danger” zone of 11-12˚C. Mr. McLeod and the pupils must have kept a very close eye on water quality!
Malcolm Thomson led the release operation and all the pupils managed to let some fry swim freely into the lovely little burn which starts its short journey to the sea in the Stromness Hills, runs under the Academy car-park through a pipe and eventually meets Scapa Flow below the school.
Extra care was needed when releasing the fish in order to avoid thermal shock and the tank water temperature which was 9°C was gently lowered by adding burn water and bringing it to around 5˚C to match the new fry environment.
Malcolm also did a few “kick-samples” by stirring the bottom of the burn and collecting micro-invertebrates into a fine mesh net. The children were able to see what the diet of their fish was going to be for the next few years: gammarus (freshwater shrimps), snails, mayfly nymphs, small worms and a chiton. It’s all very reassuring to see the larder full before our fry start feeding on their own!
A big thank you to Malcolm for making himself available and for sharing his vast knowledge of trout with the youngsters!
Mr P.
Papdale Hostel’s ova nearly all hatched.
This evening I received a worried phone call from Craig as hatching had started at the mini-hatchery kept in the bike shed, with only about 20 ova to go yet… Craig is no stranger to hatching trout eggs, since he was already involved in the pilot project back in 2011, and he quite rightly thought it was too early in comparison to the previous years… However, it just shows how much milder the winter has been this year and all schools have witnessed ova hatching earlier. The set-up at the Hostel is also quite interesting as it only relies on an air pump to produce oxygen as opposed to impeller pumps to create a current as well as air bubbles and aerate the water. The big advantage of not using an impeller pump is that you don’t have to worry about eggs or alevins getting sucked up the pump and polluting the whole tank in a matter of days if not hours.
This is their set up:
All eggs hatched on Sanday!
As we read in one of the comments by Mrs Muir on “New batch of trout eggs for the Sanday school”, the Sanday ova started hatching last Wednesday (12/02). Today, all the eggs, bar 2, had hatched and some very healthy alevins were hiding amongst the gravel. It’s interesting to go back in time in the blog and notice that in 2012, the last ova hatched around 27/02. The tank water was at 4⁰C this morning and if the weather could stay a bit chilly for the next couple of weeks, it would make the alevins’ yolk sacs last longer and we could delay the release, giving them a better chance of survival once in the wild.
Congratulations to the Sanday pupils and staff who have been monitoring the project and kept in touch. 😉
Mr P.
Rescue operation at St.Andrews!
Mrs. Reid emailed us a couple of days ago and sounded rather worried about the fate of the alevins at the St.Andrews tank… The water was murky, it was very difficult to see what was going on inside the tank and we couldn’t help thinking about last year’s disaster, when all the alevins died… Conrad, the janitor, had cleaned the pump which revealed a few eggs trapped in the impeller, had fitted a very ingenious filter and did a partial water change. Everything had been done by the book, so what could possibly go wrong?
A quick visit at the school yesterday afternoon revealed a tank full of very murky and smelly water… Hardly any alevin could be seen over the mesh grid and the water quality was obviously going down quickly. So, today, drastic measures were needed! First, most of the water was siphoned out, the mesh was removed and we discovered hundreds of healthy alevins underneath but also a lot of debris like small chunks of eggs and dead alevins which had probably fallen victim of the impeller pump… All the alevins were then transferred into a bucket full of clean rain water, the tank was cleaned, the pump was fitted with a bottle type filter and the alevins were poured back into the half-full tank, making sure the pump outlet produced plenty of water movement and air bubbles. The battle might not be won yet as the rain water we used was 4ºC colder (6.5º) than the water in the tank and some fish may have been affected by the thermal shock. This is what the tank looks like now:
Stronsay alevins are out early!
There was a new entry this morning on the Troot in the Shed 2014 homepage by James, announcing that this morning as the pupils went for their routine “troot check”, most eggs had hatched!
This is the earliest we’ve had ova hatching on Stronsay (14/02 in 2011 – 15/02 in 2012 and 18/02 in 2013) but the mild winter has probably sped up the process.
Mortality has been kept to a minimum and so far, things are looking good!
Mr P.
Hatching started at North Walls
I’ve just received a message from Mr Stout this morning saying that some ova have started hatching over the week-end! The Hoy team are still doing a great job and have kept mortality levels extremely low with only one more dead ovum.
Now that alevins are out and about, extra care will need to be taken: all pumps need to be fitted with a filter of some sort: a small bottle with pin holes no bigger than Ø 3mm or even a piece of nylon tights for pumps where a bottle cannot be fitted.
Looking forward to hearing more news about the Hoy alevins!
Mr P.
