7332

• UCREFRP Catalog Number: 7332
• Author: Valdez, R. A., et al.
• Title: Final Report Habitat Suitability Index Curves for Endangered Fishes of the Upper Colorado River Basin.
• USFW Year: 1987.
• USFW - Doc Type: \
• Copyright Material: NO

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During the first day of the workshop, the data were introduced and
described to the species experts and participants. The experts agreed that a
data point or observation (n) was defined as the data associated with a single
fish. It was also agreed that only the parameters of depth, velocity, and
substrate were available in the database to develop HSI curves. Depth was
defined as the total water depth in feet at the fish location. Velocity was
defined as the average water column velocity (at 0.6 or 0.2 and 0.8 depth) in
feet per second at the fish location. Only the dominant substrate type was
used, although a secondary substrate was specified in much of the data. The
experts recognized that most of the substrate classifications in the database
were from subjective judgement based on the Wentworth scale (See Table B-1 in
Appendix B for codes and substrate sizes). .

Also, the experts requested documentation of all habitat types in which
samples were taken (See Table B-2 in Appendix B for habitat codes and
defini tions) . I t was decided that appropriate temperature data were not
available, and an attempt should be made to develop category 1 curves at
workshop #2. The cover parameter was also missing from the database (was not
collected by most investigators), and the experts decided to identify, during
Workshop #l, life stages where this parameter may be important.

For each of the three target species, a set of nine criteria was individ-
ually evaluated to determine the type of data to include or exclude from
analyses. Nine cd teria were initially recommended by BIO,/WEST a{ld retained
throughout Workshop #1 by the panel of species experts. These criteria
included: life stage, river, strata, year, gear, time of year, time of day,
sample design, and habitat parameters.

Each criterion became a decision point at which the panel of experts was
asked if there was a need to sort or partition data. If the answer was no, the
evaluation proceeded to the next criterion. If the answer was yes, all
possible options were presented and fully evaluated. A consensus was then
reached on which of the identified partitions were to be retained. Where
multiple partitions were retained for a particular criterion, one of two
approaches was identified by the experts to guide BIOjWEST in pooling the data
or retaining the partitions. The 'test' and 'decision/test' approaches are
described in the following section entitled Stratify, Pool, and Analyze Data.

The workshop chairman conducted these decision-making exercises with the
aid of flip charts. Each size category of each species was treated separately,
and the experts decided the type of data that should be used for analysis.
This approach was used, instead of discussing each individual study, to insure
that a standard set of criteria was applied to all datasets, and to reduce the
amount of time needed to discuss each study in the 23-year span of data.

Results

Consensus of the five species experts in Workshop #1 resulted in a total
of 291 data partitions that were the basis for data analyses for possible
category 2 curves. The experts also identified 48 partitions for category 1
curve development (See Species Dendrograms, Figures 1- 8 and Table 4). A

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