7785

• UCREFRP Catalog Number: 7785
• Author: Thompson, J. M.
• Title: The Role of Size, Condition, and Lipid Content in the Overwinter Survival of Age-0 Colorado Squawfish.
• USFW Year: 1989.
• USFW - Doc Type: Colorado State University,
• Copyright Material: NO

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

23

(however, all seven of the deaths among these fish were
attributable to being suctioned onto the slotted siphon
tubes and not to depletion of fat reserves). At day 210,
only 6 of the original 90 starved medium fish were still
alive (19 were removed for lipid analysis on day 70 and 12
on day 140). As was the case with small fish, fed medium
fish showed significantly higher survival than their unfed
counterparts. At day 210, only 2 of the original 125
pellet-fed medium fish had died (27 were removed for lipid
analysis on day 70 and 12 on day 140). The medium fish that
were fed brine shrimp had 31 survivors on day 210 from the
original 32 fish. All large fish (mean length = 44 mm),
both pellet-fed and starved, were alive after 210 days
(notwithstanding a small number of large fish that died in
October-November due to the effects of ichthyobodiasis
(costiasis)). Large brine-shrimp-fed fish experienced high
mortality due to an Ichthyobodo infestation during December.
The surviving nine fish were sacrificed to prevent the
spread of the disease to the other brine-shrimp-fed fish in
the other aquaria.
Body water content is inversely related to lipid
content (Love 1970; Niimi 1972; Toneys 1977). Fish with
high fat contents tend to have lower fractions of body water
because only small amounts of water are required in the
storage of fat (Odum et al. 1964). I found that, as lipid
content decreased in age-O Colorado squawfish, percent body
water increased linearly (Figure 4).