WSP07311

• File Number: 8240.300.03
• Description: San Juan River - Recovery Implementation Program - General Info
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 1/1/1998
• Title: Secrion 9 ‎(Preliminary Draft)‎ Conclusions
• Water Supply Pro - Doc Type: Report/Study

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Develop the Conceptual Framework to Determine
Population Goals for the San Juan River Long Range Plan

Principals: Ecosystem Research Institute, Inc. and Miller Ecological Consultants, Inc.,
USFWS Grand Junction (USFWS funded separately)

Objectives:

1.) Develop a conceptual model or models which will allow the evaluation of
interim Management Objectives for the Endangered fish species and the native
fish community in the San Juan river.

2.) Develop the mechanistic models to calculate population goals for 5.1.1; 5.1.2;
5.1.3

Relationship to recovery Program objectives and research need:

Meets the needs to complete milestones in Sections 5.1; 5.1.1; 5.1.2; 5.1.3.; 5.1.4 of the
Long Range Plan

The intent of this project is to estimate the carrying capacity of the San Juan River relative to
population sizes of Colorado squawfish and razorback suckers. The approach to be taken
will be a combination of ecological and population modeling, quantitative native fish
population estimates, lower trophic level production estimates, and the transfer of upper
basin ecological data (literature review).

This approach provides an explicit framework that documents the assumptions and basis for
the population goals using empirical data from the San Juan and other Colorado River basin
rivers for the endangered and native fish community. Further, the multiple modeling
approach provides a method to verify and validate the population goals.

The modeling approach could be linked to the overall integration process for the San Juan
River.

Methods:

The first task in this project will be to develop conceptual models from the fields of
bioenergetics, habitat-based population response models, and logistic population growth
models. Because of data limitations within each type of model (ie lack of respiration data on
target species for bioenergetics or egg/yoy survivorship data needed for population modeling)
a multi modeling approach will be undertaken. The goal will be to see convergence between
model results upon application to the San Juan River.

Upon selection of the conceptual models and the evaluation of parameter inputs, a
subcommittee will be established from members of the Biology Committee to provide