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Evaluating Salmon Spawning Habitat Capacity Using Redd Survey Data
Author(s) -
Groves Phillip A.,
Chandler James A.,
Alcorn Brad,
Richter Tracy J.,
Connor William P.,
Garcia Aaron P.,
Bradbury Steven M.
Publication year - 2013
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1080/02755947.2013.793628
Subject(s) - escapement , oncorhynchus , habitat , chinook wind , fishery , carrying capacity , environmental science , fish <actinopterygii> , population , ecology , biology , demography , sociology
Management and recovery goals for fish populations often rely on estimating the number of fish that can be supported by finite habitats. In the absence of direct measures of carrying capacity, management decisions are commonly informed by results of habitat models. However, the shortcomings and spatially explicit nature of most habitat models result in making assumptions, often preclude inclusion of important variables, and are rarely validated at the reach level. We analyze long‐term, redd‐count data for a population of Chinook Salmon Oncorhynchus tshawytscha to evaluate spawning habitat capacity of a major river. Adult escapement generally increased during the years 1994–2012; consequently site use and total redd counts also increased. Together, the annual use of spawning sites and the redd counts (as functions of adult escapement) provided evidence for density‐dependent changes in the availability and capacity of spawning sites. Redd counts exceeded one recovery criterion specific to one spawning aggregate of the population during 11 years of our survey data, supporting the conclusion that adequate spawning habitat is available to attain a management goal set for this aggregate. Received May 31, 2012; accepted March 27, 2013