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Information tables associated with a risk assessment for bull trout introduction into Sullivan Lake, northeastern, Washington including population donor sources and resident species

April 28, 2022

Introduction and translocation programs require thoughtful planning to increase the likelihood of success and to understand the benefits, risks, and constraints of such programs. A risk assessment was completed for bull trout introduction into the Sullivan Lake and Harvey Creek watershed, northeastern Washington. The risk assessment was designed to evaluate potential risks to resident fish species, to bull trout introduced into Sullivan Lake, and to bull trout donor source populations. The risk assessment describes the potential risks associated with pathogens, genetics, and ecological interactions. Literature reviews were completed for fish species composition and abundance in Sullivan Lake watershed to assess potential ecological interactions and risks to these populations and to the introduced bull trout. A resident species table was designed to summarize general information to aid in assessing the type (such as predation, competition, prey) and frequency of interactions between resident species and introduced bull trout. Population status metric scores were assigned by U. S. Geological Survey (USGS) on the basis of a review of the data on past fish surveys and discussions with regional biologist. Population status metrics included: abundance, trend, and distribution, and were assigned ranking scores between 1 and 5 for the relative species composition. Species specific pathogen concerns were identified. Literature reviews were used in conjunction with discussions among regional biologists to identify and compile potential donor source populations and their population attributes into a donor source table. A decision framework was developed by USGS in collaboration with Kalispel Tribe of Indians biologists that identified desirable population attributes (life history behavior, abundance, population viability, feasibility of collection, and environmental match) associated with donor source populations and established ranking criteria. The population attribute information was used with the (1) decision framework, (2) established ranking criteria, and (3) expert opinion of regional biologists, to assign scores for overall ranking of donor source populations.