7926

• UCREFRP Catalog Number: 7926
• Author: Annear, T. C. and A. L. Conder.
• Title: Relative Bias of Several Fisheries Instream Flow Methods.
• USFW Year: n.d.
• USFW - Doc Type: Cheyenne, Wyoming.
• Copyright Material: NO

a potentially serious problem as it is difficult to know when these assump

are met without intimate familiarity with a given stream ecosystem.

dity of this assumption should not be routinely accepted as it may often

inval id.

To best identify seasonal flow needs, a combination of methods could be

used. Spawning and incubation flow needs may be addressed using PHABSIM models

and late-summer MF needs may be best addressed by habitat retention models. An

urgent need exists for a model that can assess winter MF needs.

Until one is

,
available, biologists may elect to specify, the monthly average flow for the

period of record or, perhaps, employ some modification of the habitat retention
Ii;;:;"?

mod e 1 .

Instream flow, despite all the attention directed toward the subject,

remains a vaguely defined term.

As such, the current challenge facing fishery

biologists is not the development of new models but the biological validation of

existing ones. While this study identified relative biases of several methods,

the reader is still left asking the question, which method(s) is/are be~~

The general prine ip1es, assumptions, and pred ic tive tendencies assoc iated

with each of the methods in this study apply wherever the methods are used.

However, the adequacy of any of the recommendations relative to available water

supply in a river system in any geograph~c location must be based on local

hydrologic conditions. Also, the adequacy ~f recommendations for fisheries was

not addressed in this paper and, for the present, this must still be determined

by the user on a case by case basis. The question of adequacy of any instream

method for fisheries will only be resolved by long-term biological

,
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