Individual families are kept in their own mini-downwellers before moving out to the nursery when they reach 1-2mm.
Our spawning season at ABC gets off to a later start than for commercial hatcheries. But when we do, the scope of work is intense for about three months, until the slate of crosses is complete for the year. For a while, I used to think of the hatchery as the center of operations for our breeding work, as in, it defined us. But that notion has changed.
The hatchery is only one of our tools in the breeding process. Sure, the crosses start here, but really they only stick around for 5 weeks before they are out in the nursery and, then, only in the nursery for about the same amount of time before they are in the field. Ten weeks out of about 90 (the total length of time from spawn to selection) for any given cohort (a cohort is a group of spawns that were done at the same time). Of course, what defines a breeding program is the number spawns in a cohort as well as the number of cohorts overall.
For example, first up this season was the founding population of families for our new family breeding approach. It consisted of making 130 families (a mating between one male and one female) about three weeks ago, and then a re-spawn to fill in the families that were going less well than we wanted – another 44 crosses. In the end we ended up with 115 individual cultures that made it to setting. Our first cohort, then, was 115 low salinity families. These families will be deployed to two low salinity sites in the early Fall.
Next up, our line spawns. We continue to produce our bread and butter lines – DBY, XB, Lola, and hANA – even while we are starting our new families. For lines, a cohort will consist of three lines from each of our test sites, York, Lynnhaven, and Kinsale. Three lines from York will be one cohort, three lines from Lynnhaven – another, etc.
Finally, while the larvae from the lines are still growing, we do the final set of high salinity families – another 130 or so of them. At the peak of the season, we might have about 150 individual, albeit small scale, spawns running simultaneously. During “drops” (water changes) 6 microscopes will be in use examining the larvae.
All these crosses make for a flurry of activity in the hatchery. The starting date is dictated by the arrival of our OAT (Oyster Aquaculture Training program) participants in about mid-April so we have sufficient help for the glut of spawns. The end date is dictated by the deterioration of water quality for growing larvae in mid-July. Overall, about three months of hatchery activity determines the scope of work for field tests in the following year.
Next up – Spawning Season at KAC.