I've been involved in a project to assess the condion of fish
populations in the Fraser River. Part of the work included application
of a fish health assessment index, variously adapted by Marshall Adams
from the system presented by Goede and Barton some time ago. We sampled
two species, mountain whitefish and peamouth chub at a number of areas
in the Fraser River basin.
The health assessment index uses a coding scheme to measure a deviation
from an expected "normal" condition were the fish happy and healthy.
Some of the variables in the scheme include colour of internal organs,
like liver or kidney.
The peamouth, in particular, were showing an interesting range in colour
from pale brown/beige to nearly black. Circumstances of the sampling
sites suggest that there is some contaminant exposure from upstream
discharges, but a causal link between these discharges and colour change
would be hard to prove without more work.
Anyone know of factors affecting colour in fish liver, particularly in
cyprinids? Any references so I might do some digging? Thus far, it's
been a pretty slim search so any help would be greatly appreciated!
Thanks to all -
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