Fall 2009 and Winter 2010
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Incubation Biology

Incubating salmonid eggs not only develop over time but also according to temperature. Eggs incubated at 10 C° develop twice as fast as eggs incubated at 5 C°. To keep track of the development within an egg, scientists have a system that uses "Accumulated Thermal Units" (ATU).

Simply put, 1 ATU is one degree for one day. In water of 10 C°, we would accumulate 10 ATU per day, after 13 days we would have 130 ATUs, if the water was five C°, in 13 days we would have 65 ATUs.

Below is the table representing the different ATU and life stages for the various species.

 
Eyed Eggs
Hatch Into Alevins
Emerge from incubator
Pink Salmon
350-400
550-650
900-950
Chum Salmon
300-350
475-525
900-1000
Coho
220
400-500
700-800
Chinook
280
480-540
900-1000
Sockeye
230
500-550
900-1000
Steelhead
190
330
490-530
Cuthroat
185-200
310-330
575

Calculate your egg incubation time below

Average Daily Temperature in C° (use whole degrees)

Select fish type

Date Of Fertilization