Long-term trends of bloater (Coregonus hoyi) recruitment in Lake Michigan: evidence for the effect of sex ratio

Long-term population trends are generally explained by factors extrinsic (e.g., climate, predation) rather than intrinsic (e.g., genetics, maternal effects) to the population. We sought to understand the long-term population dynamics of an important native Lake Michigan prey fish, the bloater Corego...

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Bibliographic Details
Published in:Canadian journal of fisheries and aquatic sciences 2006-04, Vol.63 (4), p.832-844
Main Authors: Bunnell, David B, Madenjian, Charles P, Croley II, Thomas E
Format: Article
Language:English
Subjects:
Agnatha. Pisces
Animal and plant ecology
Animal populations
Animal, plant and microbial ecology
Animals
Applied ecology
Biological and medical sciences
Competition
Coregonus hoyi
Demecology
Egg production
Environmental aspects
Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.)
Fish
Fishes
Freshwater
Fundamental and applied biological sciences. Psychology
Genetics
Lakes
Population biology
Predators
Sex ratio
Spring
Studies
Time series
Vertebrata
Winter
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Summary:Long-term population trends are generally explained by factors extrinsic (e.g., climate, predation) rather than intrinsic (e.g., genetics, maternal effects) to the population. We sought to understand the long-term population dynamics of an important native Lake Michigan prey fish, the bloater Coregonus hoyi. Over a 38-year time series, three 10- to 15-year phases occurred (poor, excellent, and then poor recruitment) without high interannual variability within a particular phase. We used dynamic linear models to determine whether extrinsic (winter and spring temperature, alewife predator densities) or intrinsic factors (population egg production, adult condition, adult sex ratio) explained variation in recruitment. Models that included population egg production, sex ratio, winter and spring temperature, and adult bloater condition explained the most variation. Of these variables, sex ratio, which ranged from 47% to 97% female across the time series, consistently had the greatest effect: recruitment declined with female predominance. Including biomass of adult alewife predators in the models did not explain additional variation. Overall our results indicated that bloater recruitment is linked to its sex ratio, but understanding the underlying mechanisms will require additional efforts.
ISSN:0706-652X
1205-7533
DOI:10.1139/f05-271