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Composition and location of simulated lake-shore redds influence incubation success in kokanee, Oncorhynchus nerka

Fisheries Management and Ecology

By:
, , and
DOI: 10.1111/j.1365-2400.2009.00690.x

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Abstract

Methods for improving spawning habitat for lakeshore spawning kokanee, Oncorhynchus nerka (Walbaum), were explored by quantifying incubation success of embryos exposed to three substrate treatments in Lake Pend Oreille, Idaho, USA. Substrate treatments included no modification that used existing gravels in the lake (EXISTING), a cleaned substrate treatment where existing gravels were sifted in the water column to remove silt (CLEANED) and the addition of new, silt-free gravel (ADDED). Incubation success was evaluated using Whitlock-Vibert incubation boxes buried within each substrate treatment that contained recently fertilised embryos. Upon retrieval, live and dead sac fry and eyed eggs were enumerated to determine incubation success (sac fry and eyed eggs ?? 100/number of fertilised embryos). Incubation success varied significantly among locations and redd treatments. In general, incubation success among ADDED redds (0.0-13.0%) was significantly lower than that for EXISTING (1.4-61.0%) and CLEANED (0.4-62.5%) redds. Adding new gravel to spawning areas changed the morphometry of the gravel-water interface and probably exposed embryos to disturbance from wave action and reduced embryo survival. Moreover, efforts to improve spawning habitat for lakeshore spawning kokanee should consider water depth and location (e.g. protected shorelines) as important variables. Adding clean gravel to existing spawning areas may provide little benefit if water depth or lake-bottom morphometry are altered. ?? 2009 Blackwell Publishing Ltd.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Composition and location of simulated lake-shore redds influence incubation success in kokanee, Oncorhynchus nerka
Series title:
Fisheries Management and Ecology
DOI:
10.1111/j.1365-2400.2009.00690.x
Volume
16
Issue:
5
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Fisheries Management and Ecology
First page:
395
Last page:
398
Number of Pages:
4