Manipulation
of fertilization procedures to improve hatchery walleye egg fertility and
survival
A.A.
Moore-2003
North
Americal Journal of Aquaculture, 65(1): 56-59
Abstract:
The purpose of this investigation was to determine
the effect of egg depth and the timing of semen presentation on the egg
survival of walleye Stizostedion vitreum and to alter these procedures to
improve egg fertility and subsequent survival and hatch. Tests were
conducted evaluating egg depths of 4, 7, and 10 mm and one to three semen
additions during the first minute of fertilization. The findings indicated
that an egg depth of 4 mm resulted in significantly more fertile eggs (86%)
than depths of 7 mm (77%) and 10 mm (65%) and that a 7-mm egg depth will
yield significantly more fertile eggs than a 10-mm depth. Tests using the
multiple addition of semen (extended 2: 1) to 473 mL of eggs at a depth of 4
mm resulted in the highest fertility rate of 83% when 3.0 mL of semen was
added initially and then 30 s and 60 s later, compared with a 79% fertility
rate for a single, 9.0-mL addition (P < 0.05). Using an egg depth of 12
mm and 9.0 mL of extended semen resulted in a fertility rate of 70%.
(Iowa
Dept. Nat. Resources,
Cold Springs State PK, 57744 Lewis Road, Iowa City IA 51544, USA, e-mail :
andy.moore@dnr.state.ia.us)