Breeding fish

Water birds have not been shown to be directly affected by acidification. However, the prey of waterbirds may be of concern as these lower food-chain organisms may have elevated levels of toxic metals related to acidification of their habitat. Moreover, most water birds rely on some component of the aquatic food-chain for their high protein diet. Invertebrates that normally supply caJcium to egg-laying birds or their growing chicks are among the first to disappear as lakes acidify. As these food sources are reduced or eliminated due to acidification, bird habitat is reduced and reproductive rate of the birds is affected. The Common Loon is able to raise fewer chicks, or none at all, on acidic lakes where fish populations are reduced 37 and 5S). However, in some isolated cases, food supplies can be increased when competitive species are eliminated (e.g.. Common Goldeneye ducks can better exploit insects as food when competition from fish is eliminated). The collective influences of acidification are difficult to quantify on a specific area basis but for species that rely on a healthy aquatic ecosystem to breed, acidification remains a continuing threat in thousands of lakes across eastern North America 14). 

Ovemell, J., R. McIntosh, and T.C. Fletcher. 1987. The levels of liver metallothionein and zinc in plaice, Pleuronectes platessa L., during the breeding season, and the effect of oestradiol injection. Jour. Fish Biol. 30 539-546. 

Blus, L.J. and C.J. Stafford. 1980. Breeding Biology and Relation of Pollutants to Black Skimmers and Gull-Billed Terns in South Carolina. U.S. Fish Wildl. Serv. Spec. Sci. Rep. Wildl. 230. 18 pp. 

It is common to move adult zebrafish into breeding tanks when collections of embryos are desired. This type of breeding appears to be more stressful to the fish, but in most cases, zebrafish can be bred by this method approximately once per week. 

Remove the adults by lifting the insert out of the breeding box and transferring the fish to their home tank. 

Alternatively, fish can be set up in breeding tanks in pairs or small groups with a divider separating the males from females, and the divider is removed when spawning is desired. 

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