Delayed hatching
Posted 67 days ago, on Oct 31 2008Jed Goldstone
We've recently (last 2 months) started to see delays in hatching. Normal hatch is supposed to be ~72 hpf plus or minus a few hours. We're seeing hatch rates of <10% at 96 hpf, and sometimes delays until 120 hpf. This is true using both E3 and 0.3x Daneau's, with and without methylene blue. (We have looked at both the TL and our small batch of ABs and found this). Any ideas on what to look at/modify in our systems?
1 Comments:
Christian Lawrence
So they hatch at 4-5 days post-fertilization with no problems.
Have you looked at their developmental stage as they progress? in other words, are they where they "should" be at 3 days developmentally?
Obvious things you've probably thought of are changes in environmental conditions, particularly temperature. dropping the temp even a few degrees below 26-28 will slow them down considerably.
Sometimes you will see delays in hatching in poor quality lines. In some instances, you may see this in a few individual within a single clutch. These types of observations suggest a genetic component. If you are seeing it throughout your stocks then it is more likely to be environmental.
Any changes that may have been made in the diet and/or environment over the past month or two could be underlying this.
Not easy to pinpoint but there are simple tests you could do to narrow things down.