Tuesday, February 9, 2010

Alevins

Did you know that rainbow trout were introduced into the UK from north America and the sea-going version in the USA are called 'steel head'.The Americans were very proud of that fact when we went benchmarking in north Carolina last November.They told me everything good in Europe originated in America.!!!
Anyway to continue our life cycle.The eyed eggs shown in my previous blog have hatched.The time of hatching depends on the water temperature. an enzyme is secreted which softens the eggs shell and allows the alevin to break through.The alevin has retained its yoke sac and we sometimes refere to this as the SWIM-UP stage. We don't feed as the alevin get its nutrients from the sac.I had a family who came for a visit yesterday and they were absolutely in awe.
I took this photograph this morning and it shows 2 alevin. it is quite hard to get a detailed photo and they are approximately 16mm.Another few weeks and they will loose their sac and require food. Very expensive food may I add. i just got word this morning that the food price will increase by €50/tonne which is very bad news indeed. Its a combination of fish meal/fish oil prices but you know what I have heard all the excuses before.Chin up.!!

Monday, February 1, 2010

Rainbow trout lifecycle


Not sure if you can see this image but you can google trout life cycle. We buy our eggs from a specialised hatchery in the USA and Isle of Man. we kept our own brood stock up to a number of years ago but found it much more convenient to buy them in 6-8 times a year as it is better for farm management.We could only strip eggs once a year and our brood stock took up lots of pond space and lost condition after the process . We buy our eggs from Trout lodge who are very active in research and development of the best quality eggs possible in terms of disease resistance etc. we don,t buy the cheapest but we do buy the best.

The eggs come by plane to Heathrow and are transported by road to Dublin.Unfortunately we can no longer clear these eggs in Dublin since before Christmas which is a pain.!!

The eggs are striped from the hens(females) and mixed with the milt of the cocks(males) and fertilise. They hatch at 300degree days i.e.30days at 10degree Celsius .They usually arrive at 240 degree days and will generally hatch 4-5days later depending on the water temperature here. We got these eggs 21st of December and this photo shows them just before they hatched 25th Jan.They are called eyed ova at this stage. Notice 1 egg has hatched. I will take a picture tomorrow to show you the next stage which is the Alevin stage. Isn't it fascinating. Living nature.Please send me any questions you have and feel free to make comments. I have none to date.!!!