Investigations in Concurrent Disinfection and
De-adhesion of Lake Sturgeon Eggs
H.J.
Bouchard III, D.B. Aloisi-2002
North
American Journal of Aquaculture, 64(3): 212–216
Abstract:
Recent
interest in the restoration of lake sturgeon Acipenser fulvescens and in the
development of new culture techniques has led to many new management
programs designed to stabilize and enhance existing wild populations. The
spread of pathogens affecting both wild and propagated sturgeon is a major
concern for restoration programs. In 1999, two methods of egg de-adhesion
were used on two separate groups of lake sturgeon eggs prior to disinfection
with 100 mg/L of iodine for 10 min. The de-adhesion of eggs with
urea-NaCl–tannic acid solutions produced hatch and 14-d-posthatch survival
rates of 77.2% and 71.0%, respectively. These results were compared with
those for eggs treated with Fuller's Earth (control), which had survival
rates of 88.0% and 86.0%, respectively, at hatch and 14 d. In 2000, we
compared three methods of de-adhesion: (1) a solution of distilled water
(jelly inhibitor) and iodine, (2) a solution of urea, NaCl, and tannic acid,
and (3) a solution of Fuller's Earth and iodine. With all three methods,
eggs were disinfected with a 50-mg/L buffered iodine solution for 30 min
during or immediately following de-adhesion. Survival to hatchout for the
distilled water, urea-NaCl-tannic acid, and Fuller's Earth methods was 95.3,
99.6, and 97.7%, respectively. Survival to 14 d posthatch was 76.8, 84.2,
and 85.6%, respectively, for the three methods. Iodine disinfection during
the de-adhesion and water absorption processes does not appear to be toxic
to lake sturgeon eggs. Topical iodine disinfection of lake sturgeon eggs
immediately (<10 min) following fertilization increased the exposure of
both the internal and external portions of the egg to the iodine during the
hydration of the egg envelope.
(U.
S. Fish and Wildlife Service, Pittsford National Fish Hatchery, 4 Holden
Road, North Chittenden, Vermont 05763, USA)