**ABSTRACT NOT FOR CITATION WITHOUT AUTHOR PERMISSION. The title, authors, and abstract for this completion report are provided below. For a copy of the full completion report, please contact the author via e-mail at troy@purdue.edu; thook@purdue.edu; dbunnell@usgs.gov . Questions? Contact the GLFC via email at frp@glfc.org or via telephone at 734-662-3209.**
DEVELOPMENT
AND CORRELATION OF PHYSICAL PROCESS INDICES WITH INTER-ANNUAL RECRUITMENT
VARIABILITY IN LAKE MICHIGAN
2 Lyles
School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West
Lafayette, IN,47907-2051
3 Department
of Forestry and Natural Resources, Purdue University, 715 W. State Street, West
Lafayette, IN 47907-2061
4 Great
Lakes Science Center, United States Geological Survey, 1451 Green Road, Ann
Arbor, MI, 48105-2807
July 2017
ABSTRACT:
This project examined the relationship between interannual fish recruitment variability, synchrony, and
potential physical drivers of recruitment.
First, multiple fish species in Lake Michigan were examined for spatial
synchrony in recruitment, and linkages between this synchrony and interannual climate variation. Fish species examined included bloater (Coregonus hoyi),
rainbow smelt (Osmerus mordax),
yellow perch (Perca flavescens),
and alewife (Alosa pseudoharengus).
Residuals from stock–recruitment relationships
revealed yellow perch recruitment to be correlated with recruitment of both rainbow smelt (r = 0.37) and alewife (r =0.36).
Across all four species, recruitment synchrony was manifested as higher than
expected recruitment in 5 years between 1978 and 1987 and then lower than
expected recruitment in 5 years between 1996 and 2004. Generalized additive
models revealed warmer spring and summer water temperatures and lower wind
speeds corresponded to higher than expected recruitment for the nearshore spawning
species, and overall variance explained ranged from 14% (yellow perch) to 61%
(alewife). For all species but rainbow smelt, higher recruitment also occurred
in extremely high or low years of the North Atlantic Oscillation index. Additional work investigated inter-annual (1966–2008)
variation in yellow perch (Perca flavescens) recruitment using 16 combined datasets
describing populations located in four of the five Laurentian Great Lakes
(Erie, Huron, Michigan, and Ontario) and Lake St. Clair. Relative year-class
strength (RYCS) was indexed using catch-curve residuals for each year-class across
2–4 years and compared relative year-class strength among sampling locations.
Results indicate that perch recruitment is positively synchronized across the
region. In addition, the spatial scale of this synchrony appears to be broader –
approximately 150km - than previous estimates for both yellow perch and
freshwater fish in general. Year-class strength was compared to regional
indices of annual climatic conditions (spring-summer air temperature, winter air
temperature, and spring precipitation) using data from 14 weather stations
across the Great Lakes region. Regional recruitment synchrony was found to be
positively related to spring-summer air temperature, suggesting that at least
one abiotic factor is responsible for the observed synchrony. Work examining inter-annual variation in
recruitment among lake whitefish (Coregonus clupeaformis) populations in lakes Huron, Michigan and
Superior was carried out, using fishery-dependent and -independent data from
1971 to 2014. RYCS was calculated from catch-curve residuals for each year-class
across multiple sampling years to quantify annual recruitment success. Pairwise
comparison of RYCS among datasets revealed no significant associations either
within or between lakes, suggesting that recruitment of lake whitefish – unlike
yellow perch - is spatially asynchronous. There was no consistent correlation between
pairwise agreement and the distance between datasets, and models to estimate
the spatial scale of recruitment synchrony did not fit well to these data.
These results suggest that inter-annual recruitment variation of lake whitefish
is asynchronous across broad spatial scales in the Great Lakes. Because these findings differ from research
on some other Coregonus
species, they are suggestive that local biotic or density-dependent factors may
contribute strongly to lake whitefish recruitment rather than inter-annual
variability in broad-scale abiotic factors.
Ongoing work seeks to quantify interannual
variations in physical processes that may be linked to recruitment synchrony,
in particular variations in air/water temperatures and over-lake winds.