7782

• UCREFRP Catalog Number: 7782
• Author: Toney, D. P.
• Title: Observations on the Propagation and Rearing of Two Endangered Fish Species in a Hatchery Environment
• USFW Year: 1974
• USFW - Doc Type: Proc. of the Western Association of State Game & Fish Committees
• Copyright Material: YES

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Control of the parasite was attempted by moving the fish to an indoor
holdirig tank~ where a rapid water flowcauld be maintained. The condition
of the fish deteriorated rapidly and fungused areas began to appear over the
body. A rough estimate of the number of parasites was 100 per square inch
over the entire body. The fish were painted \'/ith 1/1000 of potassium per....an-
ganate with little, if any, benefits. By mid-April, it was evident that a
control had to be found or we would lose the fish. It was decided to move the
fish back to the outside holding facility and allow the water temperature to
rise, to accelerate the life cycle of the parasite. In the process, we-painted
the fish with potassium permanganate and one died a few hours later. The fish
that died was frozen, and subsequent examination by Biologist Rosenlund
revealed numerous myxosoma spores, species undetermined, in the liver and
kidney.

Twenty-five milligrams per liter of formalin and .05 milligrams per liter
malachite green (Leteux and ~\eyer, 1972) was added to the water every other day
for three weeks, beginning April 16th. Water temperature of 550F. rose to
6l.toF. over this period. The condition of the fish began to improve within two
days, and no parasites could be found after three weeks.

Spawning

./

When initially received, the fish appeared to be in spa\...ning conditio71.
A first attempt at hand stripping was unsuccessful on ,L\ugust 1L;, 1973. TrIO
mature males, producing sperm, and, possibly, two females \'/ere found. 0" the
21st of August, three possible females, no t~bercles, were injected with
chorionic gonadotrophin, 900 units per pound. Checks over the next t\VO \-leeks
produced nothing, with the exception that the males discontinued sperm produc-
tion. This was rather disheartening, but we also felt partially successful,
because we had mature males and probably three females.

Plans for the coming year included temperature regulation, a plentif~l
food suppiy, and the previously described gravel spawning area. ~!ater recircu-
lation and temperature in the high sixties to mid-seventies Has maintained
until mid-October. At this time, the recirculation was discontinued, and
550F. river \...ater was run through the holding facility. We planned to CO:1tinue
the S50F. river water until mid-Hay the following year, and then start recircu-
lation to allow the temperature to gradually rise to 760F.

As previously noted, the recirculation was started a month early, due to
the parasite problem. Water temperature of 6l.toF. on the first of May gradually
rose to 690F. by the end of May. Temperatures varied from lOoF. to 740F.
during the month of June. We weighed, measured and tagged the fish on May 30,
1974. We also noted any external sexual characteristics.

Three of the fish had tubercles on the tip of the snout and on the opercu-
lum. Two of these produced a very watered down appearing milt. The lensth of
the genital papillae was 7/16 of an inch on the three probable fer.~les. On
the males, it \olas 5/16 of an inch on two, and 1/2 inch on the other. Papilla
length, or protru"ion, appears to be the opposite of that for Columbia squaw-
fish Ptychocheilus oregonerlsis (Jeppson, 195]). He stated that one exte.;)al

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