The effect of sodium and calcium concentrations on the hatching of eggs and the survival of the yolk sac fry of brown trout, Salmo trutta L. at low pH |
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| Authors: | D J A Brown S Lynam |
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| Institution: | C.E.R.L. Freshwater Biology Unit, Midlands Region, Scientific Services Department, Ratcliffe-on-Soar, Nottingham NG11 0EE, U.K. |
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| Abstract: | The effect of various external concentrations of sodium and calcium on the survival and hatching of brown trout, Salmo trutta , eggs at pH 4.5 was tested. A calcium concentration of approximately 10 ppm (500 μE l−1) enables freshly fertilized eggs to survive whereas eyed ova are tolerant of deionized water acidified by sulphuric acid with no other ions added. Concentrations of sodium and calcium of 1 ppm (44 and 50 μE l−1, respectively) are sufficient to ensure the successful hatching of eyed ova and subsequent survival of the alevins. At pH 4.5 hatching is prolonged by the alevins passing through a temporary encapsulated stage. |
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