7016

• UCREFRP Catalog Number: 7016
• Author: Larval Fishes Laboratory.
• Title: Development of Marking and Otolith-ageing Techniques for Colorado Squawfish
• USFW Year: 1986.
• USFW - Doc Type: Report on Study-Phase 1.
• Copyright Material: NO

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!I -F= `'hi =e rr/1 m'. 4, 12 end h^'Irr' 3 5;7e
mg/l at 4, 12, an-di 36 hours; 500 mg/l at 4, 12, and
36 hours) with one control per life stage = 10
lots per life stage.
--Three life stages will be tested (see Muth et al.
1985 for roundtail chub developmental data): (1)
embryo (pigmented eye stage; for roundtail chub,
ca 105 hours after fertilization), newly hatched
larvae (early protolarva; for roundtail chub, ca
126-156 hours after fertilization), and pre
swim-up larvae (late protolarva; for roundtail
chub, swim-up occurs ca 48 hours after hatching);
three life stages X 10 lots per life stage = 30
lots.
--100-200 eggs/larvae per lot.
--Marking will be conducted in 1,000 ml beakers
containing the pH adjusted solutions; solutions
will be aerated and beakers placed in constant
temperature (19-20C) flow-through water baths;
larvae will not be fed during marking.
--After marking, 10 specimens from each lot will be
fixed and preserved; five in phosphate buffered
formalin (buffered near neutral; 10% buffered
formalin initial fixative, after 24 hr transferred
to 3% buffered formalin for preservation) and five
in 95% ethyl alcohol. The remaining eggs/larvae
will be transferred from the marking beakers to
three pairs of flow-through troughs (each pair
divided into 10 sections = 30 lots; eggs/larvae
will either be placed directly into troughs or
placed in containers, e,g., aerated jars). Samples
of 10 specimens from each lot will be taken every
seven days and fixed/preserved in the same manner
as noted above. Samples will be placed in separate
containers, labeled, and stored in the dark.
--Lots will be checked twice daily and dead fish-
removed, recorded, and preserved.
--Larvae (post swim-up) will be fed twice daily
(morning and evening) with brine shrimp nauplii
and commercial TetraMin Fry Diet and Staple Food.
--Water chemistry parameters (i.e., DO, pH, and
total water hardness) and water temperature will
be monitored during the experiment.
--Otoliths will be removed from specimens, mounted
on slides and examined under U-V light microscope
(Zeiss flourescent microsope, CSU Department of
Pathology, contact Charlie Curley). Precise
procedures will have to be worked out once
otoliths are removed from the specimens. It may
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