Breeding Oysters

Breeding has been a hallmark of agriculture since humans first adopted farming. Darwin used the principles of breeding to deduce the mechanism of evolution—slow, incremental change due to natural variability, carried out over many successive generations.

At ABC, our primary goals are to use family breeding to improve survival through disease resistance, and to increase growth rate so oysters can reach market size faster

Why does ABC use family breeding?

Oyster breeding programs around the world typically employ either line breeding or family breeding techniques, or some combination of both. Line breeding occurs when a group of oysters with a desirable characteristic are bred together in a mass spawn (lots and lots of parents) to produce or enhance the desirable quality in their offspring. Family breeding goes a step further, where individual male and female oysters with a desirable quality are mated together to create a family of siblings. Data on full-sibling and half-sibling families allows researchers to better understand the variability and heritability of a trait.

Breeding for disease resistance

Certain natural oyster populations have been shown to harbor resistance to the diseases MSX and Dermo. For example, Louisiana oyster populations are tolerant to dermo disease. ABC researchers are systematically examining disease resistance genes by selecting oysters that exhibit the highest survival rates in the face of strong, moderate, and weak disease pressure. They accomplish this by planting oysters at several different locations around Chesapeake Bay and monitoring their survival for up to two years. Multiple site locations allow researchers to tailor lines to the environments in which they will be commercially grown.

Breeding for fast growth rate

Commercial operations aim to harvest their crop in 18 months. Can this milestone be improved by selecting the fastest growing oysters as parents of the next generation? The answer is “yes.”  How early in the grow-out cycle, then, is it possible to select these fast-growing oysters? Early selection can reduce the handling of oysters in the field and perhaps shorten the generation time from two years to one year. ABC uses their family breeding program to estimate the correlations between early and late growth to make farms as efficient as possible.

Other Breeding Programs

Breeding in aquaculture is a relatively new activity, yet several oyster-breeding programs have sprung up around the world. These include the