Multivariate Time Series Analysis of the Canadian Fisheries System in Lake Superior

Data for the Canadian fisheries system in Lake Superior were organized into monthly time series of catch and effort from January 1963 through December 1976 for six fish species. Multivariate, autoregressive (ARMA) models were identified for the system based on data for the first 140 mo. Forecasts were compared to data for the last 28 mo. The structure of the models indicate that (1) within the system, AR processes, as opposed to MA processes, were of overriding importance, (2) intraspecific interactions (inferred from data on catch-per-unit-effort, CPUE) were more prevalent than interspecific interactions, (3) interactions within the system occurred with lags of 1, 4, 12, 24, 25, 28, and 36 mo, (4) some of the trophic relationships among the fish species were revealed by the models, and (5) CPUE time series of lake trout (Salvelinus namaycush) affected, but was not affected by, the CPUE time series of other species. The models were used to forecast catch and CPUE for the last 28 mo, and the data were generally within one standard error of the forecasts. The models may help policy decision makers to explore the effects of inputs (e.g. quota regulations) and feedbacks within the fisheries' system on outputs (e.g. production, CPUE).

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Changes in Species Interactions of the Lake Superior Fisheries System After the Control of Sea Lamprey as Indicated by Time Series Models

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-028 ◽

1990 ◽

Vol 47 (2) ◽

pp. 251-261 ◽

Cited By ~ 3

Author(s):

Jeff N. Stone ◽

Yosef Cohen

Keyword(s):

Time Series ◽

Fish Species ◽

Species Interactions ◽

Lake Trout ◽

Interspecific Interactions ◽

Sea Lamprey ◽

Trophic Relationships ◽

Time Series Models ◽

Catch Per Unit Effort ◽

Intraspecific Interactions

Interspecific and intraspecific interactions of fish species in the Canadian commercial fisheries changed following the control of sea lamprey (Petromyzon marinus). These changes were detected by a multivariate time series (MVTS) analysis of monthly time series of catch-per-unit-effort for lake trout (Salvelinus namaycush), lake whitefish (Coregonus clupeaformis), lake herring (C. artedii), chubs (Coregonus spp.), walleye (Stizostedion vitreum), and yellow perch (Perca flavescens). The identified MVTS models reflected known trophic relationships among fish species and indicated that significant intraspecific interactions were more numerous than interspecific interactions. Lake trout interactions with other species appear to have changed due to stocking and diet change. Single species time series models confirmed the lag structure of the MVTS models and were useful for forecasting abundance.

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Vulnerability, Stability, and Coherence of the Fish Community in Lake Superior

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-341 ◽

1987 ◽

Vol 44 (S2) ◽

pp. s404-s410 ◽

Cited By ~ 4

Author(s):

Y. Cohen ◽

J. N. Stone ◽

T. L. Vincent

Keyword(s):

Fish Species ◽

Spectrum Analysis ◽

Structural Changes ◽

Lake Trout ◽

Lake Superior ◽

Sea Lamprey ◽

Dominant Frequency ◽

Vulnerability Analysis ◽

Predatory Fish ◽

Before And After

Vulnerability analysis and spectrum analysis were found useful in examining potential structural changes in fisheries systems influenced by large perturbations. In the 1950's the Ontario fisheries of Lake Superior experienced a major perturbation due to invasion by sea lamprey (Petromyzon marinus). Vulnerability analysis indicated that invasion by sea lamprey and the consequent shifting of the fisheries to more intensive fishing on lower trophic level species resulted in higher vulnerability of the predatory fish species; i.e. likelihood of extinction increased. Spectrum analysis was then applied to the yield series of five fish species from Lake Superior. Analysis of the data before and after invasion by sea lamprey indicated major structural changes in the fishery: (1) except for lake trout (Salvelinus namaycush), either the dominant amplitude, the dominant frequency, or both decreased; (2) partial coherencies between pairs of yield series changed after the invasion; (3) lake whitefish (Coregonus clupeaformis) and lake trout replaced lake herring (C. artedii) as the species whose fluctuations in commercial yield were most highly synchronized with those of the other species of commercial importance.

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A stable isotope evaluation of the structure and spatial heterogeneity of a Lake Superior food web

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f00-072 ◽

2000 ◽

Vol 57 (7) ◽

pp. 1395-1403 ◽

Cited By ~ 58

Author(s):

Chris J Harvey ◽

James F Kitchell

Keyword(s):

Stable Isotope ◽

Spatial Heterogeneity ◽

Food Web ◽

Lake Trout ◽

Trophic Position ◽

Lake Superior ◽

Salvelinus Namaycush ◽

Trophic Relationships ◽

Rainbow Smelt ◽

Western Lake

We used stable isotope analysis to derive trophic relationships and movement patterns for components of the western Lake Superior food web. Trophic linkages implied by previous gut content studies were only marginally supported by stable isotope data. Siscowet lake trout (Salvelinus namaycush siscowet) were the top predators, and trophic overlap between siscowet and lean lake trout (Salvelinus namaycush) was low. Exotic Pacific salmon (Oncorhynchus spp.) occupied a lower trophic position than native piscivores because the latter relied more on coregonids. To evaluate spatial heterogeneity of the food web, we assumed that the adjacent cities of Duluth and Superior (DS) were a point source of 15N, and we measured isotopes of organisms close to and far from DS. Slimy sculpin (Cottus cognatus) were enriched in the DS area relative to other sites, implying that they are relatively sedentary. Rainbow smelt (Osmerus mordax) showed no differences at any sites, implying high vagility. Other organisms showed differences that could not be attributed to DS, implying that other mechanisms, such as trophic ontogeny, were influencing their isotopic signatures.

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Changes in Mortality of Lake Trout (Salvelinus namaycush) in Michigan Waters of Lake Superior in Relation to Sea Lamprey (Petromyzon marinus) Predation, 1968–78

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-247 ◽

1980 ◽

Vol 37 (11) ◽

pp. 2063-2073 ◽

Cited By ~ 23

Author(s):

Richard L. Pycha

Keyword(s):

Fishery Management ◽

Lake Trout ◽

Lake Superior ◽

Petromyzon Marinus ◽

Total Mortality ◽

Sea Lamprey ◽

Salvelinus Namaycush ◽

Catch Per Unit Effort ◽

Instantaneous Rate ◽

Unit Effort

Total mortality rates of lake trout (Salvelinus namaycush) of age VII and older from eastern Lake Superior were estimated from catch curves of age distributions each year in 1968–78. The instantaneous rate of total mortality Z varied from 0.62 to 2.31 in close synchrony with sea lamprey (Petromyzon marinus) wounding rates on lake trout. The regression of transformed Z on the index of lamprey wounding, accounted for over 89% of the variation in lake trout mortality (r2 = 0.893). An iterative method of estimating rates of exploitation u, instantaneous rates of fishing mortality F, K (a constant relating sample catch per unit effort to population size), instantaneous normal natural mortality rate M, and instantaneous rate of mortality due to sea lamprey predation L from the sample catch per unit effort and total catch by the fishery is presented. A second method using the results of a 1970–71 tagging study to estimate the mean F in 1970–77 yielded closely similar results to the above and is presented as corroboration. The estimates of u, F, and M appear to be reasonable. F ranged from 0.17 in 1974 to 0.42 in 1969 and M was estimated at 0.26. L varied from 0.21 in 1974 to 1.70 in 1968. Management implications of various policies concerning sea lamprey control, exploitation, and stocking are discussed.Key words: lake trout, sea lamprey, lamprey control, mortality, predation, Lake Superior, fishery, management

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