Editing Selective breeding (section)

====Oysters====

Selection for live weight of Pacific oysters showed improvements ranging from 0.4% to 25.6% compared to the wild stock.<ref>{{Cite journal | doi = 10.1016/s0044-8486(02)00621-x| title = Yields of cultured Pacific oysters Crassostrea gigas Thunberg improved after one generation of selection| journal = Aquaculture| volume = 220| issue = 1–4| pages = 227–244| year = 2003| last1 = Langdon | first1 = C. | last2 = Evans | first2 = F. | last3 = Jacobson | first3 = D. | last4 = Blouin | first4 = M. | bibcode = 2003Aquac.220..227L}}</ref> Sydney-rock oysters (''Saccostrea commercialis'') showed a 4% increase after one generation and a 15% increase after two generations.<ref>{{Cite journal | doi = 10.1016/0044-8486(96)01328-2| title = Progress in a Sydney rock oyster, Saccostrea commercialis (Iredale and Roughley), breeding program| journal = Aquaculture| volume = 144| issue = 4| pages = 295–302| year = 1996| last1 = Nell | first1 = J. A. | last2 = Sheridan | first2 = A. K. | last3 = Smith | first3 = I. R. | bibcode = 1996Aquac.144..295N}}</ref><ref>{{Cite journal | doi = 10.1016/s0044-8486(98)00408-6| title = Third generation evaluation of Sydney rock oyster Saccostrea commercialis (Iredale and Roughley) breeding lines| journal = Aquaculture| volume = 170| issue = 3–4| pages = 195–203| year = 1999| last1 = Nell | first1 = J. A. | last2 = Smith | first2 = I. R. | last3 = Sheridan | first3 = A. K. | bibcode = 1999Aquac.170..195N}}</ref> Chilean oysters (''Ostrea chilensis''), selected for improvement in live weight and shell length showed a 10–13% gain in one generation.
Bonamia ostrea is a protistan parasite that causes catastrophic losses (nearly 98%) in European flat oyster ''Ostrea edulis'' L. This protistan parasite is endemic to three oyster-regions in Europe. Selective breeding programs show that ''O. edulis'' susceptibility to the infection differs across oyster strains in Europe. A study carried out by Culloty et al. showed that 'Rossmore' oysters in Cork harbour, Ireland had better resistance compared to other Irish strains. A selective breeding program at Cork harbour uses broodstock from 3– to 4-year-old survivors and is further controlled until a viable percentage reaches market size.<ref>{{Cite journal | doi = 10.1016/s0044-8486(01)00569-5| title = An investigation into the relative resistance of Irish flat oysters ''Ostrea edulis'' L. to the parasite ''Bonamia ostreae''| journal = Aquaculture| volume = 199| issue = 3–4| pages = 229–244| year = 2001| last1 = Culloty | first1 = S. C. | last2 = Cronin | first2 = M. A. | last3 = Mulcahy | first3 = M. I. F. }}</ref><ref>{{Cite journal | doi = 10.1016/j.aquaculture.2004.04.007| title = Potential resistance of a number of populations of the oyster ''Ostrea edulis'' to the parasite ''Bonamia ostreae''| journal = Aquaculture| volume = 237| issue = 1–4| pages = 41–58| year = 2004| last1 = Culloty | first1 = S. C. | last2 = Cronin | first2 = M. A. | last3 = Mulcahy | first3 = M. F. | bibcode = 2004Aquac.237...41C}}</ref>

Over the years 'Rossmore' oysters have shown to develop lower prevalence of ''B. ostreae'' infection and percentage mortality. Ragone Calvo et al. (2003) selectively bred the eastern oyster, ''Crassostrea virginica'', for resistance against co-occurring parasites ''Haplosporidium nelson'' (MSX) and ''Perkinsus marinus'' (Dermo). They achieved dual resistance to the disease in four generations of selective breeding. The oysters showed higher growth and survival rates and low susceptibility to the infections. At the end of the experiment, artificially selected ''C. virginica'' showed a 34–48% higher survival rate.<ref>{{Cite journal | doi = 10.1016/s0044-8486(02)00399-x| title = Dual disease resistance in a selectively bred eastern oyster, ''Crassostrea virginica'', strain tested in Chesapeake Bay| journal = Aquaculture| volume = 220| issue = 1–4| pages = 69–87| year = 2003| last1 = Ragone Calvo | first1 = L. M. | last2 = Calvo | first2 = G. W. | last3 = Burreson | first3 = E. M. | bibcode = 2003Aquac.220...69R}}</ref>