As explained in previous posts, the Sanday mini-hatchery was, this year, subjected to the vagaries of the Orcadian winter and boy, wasn’t it an interesting one…
By early-March the floating basket containing the ova became encased in 6in. of ice for a few days! This doesn’t sound too unusual for many parts of the country but Orkney winters tend to be much milder as can be seen on the graphs below:
By the time the thaw came, nobody was expecting the fragile trout eggs to have survived the freezing conditions! However, we had underestimated their resilience and forgotten that brown trout did thrive in Britain through the various ice ages when they certainly would have been confronted to much nastier weather conditions! This was a very pleasant surprise and during the weeks which followed, the alevins reabsorbed their yolk sacs and were ready to be released in the wild by the end of April, nearly a month later than in the previous years.
As we were by the Bea Loch in early spring, it was a good opportunity to do a bit of “kick sampling” with fine mesh nets and find out what our trout would be feeding in the years to come. The pupils caught huge amounts of freshwater shrimps (Gammarus), water boatmen (Corixa) and even a stickleback, which shows how rich those North Isles lochs are!