Mc. Fabrizio et al., Using linear models with correlated errors to analyze changes in abundanceof Lake Michigan fishes: 1973-1992, CAN J FISH, 57(4), 2000, pp. 775-788
Citations number
32
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
We examined annual changes in relative abundance of Lake Michigan fishes us
ing linear models with correlated errors in space and time. Abundance of bl
oater (Coregonus hoyi), deepwater sculpin (Myoxocephalus thompsoni), slimy
sculpin (Cottus cognatus), alewife (Alosa pseudoharengus), and rainbow smel
t (Osmerus mordax) was monitored with bottom trawls at 10 discrete depths (
between 18 and 110 m) off eight fixed ports from 1973 to 1992. The model de
scribing abundance included fixed effects of year, port, depth, and interac
tion terms as well as quadratic and cubic effects of year and depth because
changes in abundance were not strictly linear. Observed temporal trends in
abundance varied with species and depth. Additionally, trends in alewife a
nd slimy sculpin abundances depended on port. Cubic trends in the abundance
of bloater and quadratic trends in deepwater sculpin and rainbow smelt abu
ndances were similar among ports, permitting lakewide inferences for these
species. Mean bloater abundance was low throughout the 1970s, increased dur
ing the 1980s, and reached high levels by 1990. Mean abundances of deepwate
r sculpin and rainbow smelt increased from 1973 to the mid-1980s and declin
ed thereafter. The linear model with correlated errors can be readily appli
ed to repeated-measures data from other fixed-station fishery surveys and i
s appropriate for data exhibiting spatial and temporal autocorrelations.