The dominant attached filamentous algae of Georgian Bay, the North Channel and Eastern Lake Huron: Field ecology and biomonitoring potential during 1980

Hydrobiologia ◽  
1988 ◽  
Vol 163 (1) ◽  
pp. 149-171 ◽  
Author(s):  
Michael B. Jackson
Keyword(s):  
Lake Huron ◽  
Filamentous Algae ◽  
Georgian Bay ◽  
The North

Gravitational oscillations of Lake Huron, Saginaw Bay, Georgian Bay, and the North Channel

1977 ◽  
Vol 82 (15) ◽  
pp. 2105-2116 ◽  
Author(s):  
David J. Schwab ◽  
Desiraju B. Rao
Keyword(s):  
Lake Huron ◽  
Saginaw Bay ◽  
Georgian Bay ◽  
The North

Lake Huron: Effects of Exploitation, Introductions, and Eutrophication on the Salmonid Community

1972 ◽  
Vol 29 (6) ◽  
pp. 877-887 ◽  
Author(s):  
A. H. Berst ◽  
G. R. Spangler
Keyword(s):  
Water Quality ◽  
Fishery Management ◽  
Management Practices ◽  
Quality Criteria ◽  
Sea Lamprey ◽  
Lake Huron ◽  
Water Quality Criteria ◽  
Saginaw Bay ◽  
Georgian Bay ◽  
The North

Lake Huron is a large, deep, oligotrophic lake, centrally located in the St. Lawrence Great Lakes system. Manitoulin Island and the Bruce Peninsula divide the lake into the relatively discrete water masses of the North Channel, Georgian Bay, and Lake Huron proper. Water quality in Lake Huron has deteriorated only slightly since the early 1800s. The only significant changes are confined to areas adjacent to centers of human activity, chiefly Saginaw Bay and various harbours and estuaries in Georgian Bay and the North Channel. The lake has supported a commercial fishery which has produced annual catches as high as 13000 metric tons. A dramatic decline in landings of commercially valuable species and an instability in fisheries resources has occurred in all areas of the lake since the 1940s. This depression of populations of valued species was associated with the accidental introduction of the sea lamprey, instances of overfishing and deterioration of water quality in Saginaw Bay. The present depressed state of the fisheries will undoubtedly persist until sea lamprey control is achieved and climax predators are reestablished. Governments are proceeding toward the establishment of water quality criteria and fishery management practices which, hopefully, will stabilize the fisheries and prevent further deterioration of the aquatic environment.

A comparison of the effectiveness of sea lamprey control in Georgian Bay and the North Channel of Lake Huron

Hydrobiologia ◽  
1988 ◽  
Vol 163 (1) ◽  
pp. 215-222 ◽  
Author(s):  
B. G. Herbert Johnson
Keyword(s):  
Sea Lamprey ◽  
Lake Huron ◽  
Georgian Bay ◽  
The North

Density-dependent growth of double-crested cormorant colonies on Lake Huron

2006 ◽  
Vol 84 (10) ◽  
pp. 1409-1420 ◽  
Author(s):  
Mark S. Ridgway ◽  
J. Bruce Pollard ◽  
D.V. Chip Weseloh
Keyword(s):  
Time Series ◽  
Population Growth ◽  
Carrying Capacity ◽  
Colony Size ◽  
Lake Huron ◽  
Population Increase ◽  
Density Dependent ◽  
Georgian Bay ◽  
The North ◽  
Dependent Growth

By analyzing 20+ years of data, we found that the nesting colonies of double-crested cormorants ( Phalacrocorax auritus (Lesson, 1831)) in the North Channel and Georgian Bay of Lake Huron exhibit density-dependent population regulation. This conclusion is based on four lines of evidence. First, a time series of nest counts at specific colonies (1979–2001) showed density-dependent growth based on randomization tests of the time series. Second, the per capita rate of change in colony size declined with increasing colony size over a 10-year period. Third, a Ricker model of aggregate nest counts showed that population growth of nesting double-crested cormorants stabilized in recent years (through 2003), with K, the carrying capacity parameter, being 11 445 nests in the North Channel and 10 815 nests in Georgian Bay. Fourth, a colony area index showed near complete coverage of coastal areas by adult nesters coinciding with overall declines in population growth. High rates of population increase of double-crested cormorants on Lake Huron have largely come to an end, but changes in fish abundance may result in changes in carrying capacity.

Coastal zone occupancy by double-crested cormorants on a Laurentian Great Lake before, during, and after a food web regime shift

2015 ◽  
Vol 72 (7) ◽  
pp. 1004-1014 ◽  
Author(s):  
Mark S. Ridgway ◽  
Trevor A. Middel
Keyword(s):  
Food Web ◽  
Coastal Zone ◽  
Regime Shift ◽  
Lake Huron ◽  
Alosa Pseudoharengus ◽  
Occupancy Models ◽  
Coastal Habitat ◽  
Coastal Regions ◽  
Georgian Bay ◽  
The North

The Lake Huron food web has been undergoing change since the invasion of driessenid mussels (Dreissena spp.) (late 1990s), especially in 2003 featuring the lake-wide loss of alewife (Alosa pseudoharengus) among other elements that year. Collectively the changes in 2003 satisfy a number of criteria for a regime shift. Based on multiflight surveys (2001–2005), we modeled coastal zone occupancy of foraging double-crested cormorants (Phalacrocorax auritus) in the North Channel and Georgian Bay of Lake Huron during the regime shift period. At the start of the regime shift (2003), there were a number of plausible occupancy models based on a set of spatial covariates, the only year in the study when this occurred. Annual shifts in the magnitude and sign of coefficients indicated movement of cormorants between the two coastal regions, especially during and immediately after the regime shift period. Declines in cormorant occupancy of coastal habitat were not confined to 2003 but extended through 2004, with declines in occupancy in the North Channel (2003) preceding that in Georgian Bay (2004). Declines in occupancy in offshore areas in both coastal regions preceded declines in nearshore areas, possibly reflecting the loss of alewife at the time. The spatial response of predators or prey in regime shifts could serve as early indicators of tipping points in ecosystems.

scholarly journals Toxins and Other Bioactive Metabolites in Deep Chlorophyll Layers Containing the Cyanobacteria Planktothrix cf. isothrix in Two Georgian Bay Embayments, Lake Huron

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 445
Author(s):  
Arthur Zastepa ◽  
Todd R. Miller ◽  
L. Cynthia Watson ◽  
Hedy Kling ◽  
Susan B. Watson
Keyword(s):  
Thermal Stratification ◽  
Chemical Defence ◽  
Euphotic Zone ◽  
Lake Huron ◽  
Metabolic Inhibitors ◽  
Bioactive Metabolites ◽  
Total Biomass ◽  
Key Factors ◽  
Georgian Bay ◽  
And Function

The understanding of deep chlorophyll layers (DCLs) in the Great Lakes—largely reported as a mix of picoplankton and mixotrophic nanoflagellates—is predominantly based on studies of deep (>30 m), offshore locations. Here, we document and characterize nearshore DCLs from two meso-oligotrophic embayments, Twelve Mile Bay (TMB) and South Bay (SB), along eastern Georgian Bay, Lake Huron (Ontario, Canada) in 2014, 2015, and 2018. Both embayments showed the annual formation of DCLs, present as dense, thin, metalimnetic plates dominated by the large, potentially toxic, and bloom-forming cyanobacteria Planktothrix cf. isothrix. The contribution of P. cf. isothrix to the deep-living total biomass (TB) increased as thermal stratification progressed over the ice-free season, reaching 40% in TMB (0.6 mg/L at 9.5 m) and 65% in South Bay (3.5 mg/L at 7.5 m) in 2015. The euphotic zone in each embayment extended down past the mixed layer, into the nutrient-enriched hypoxic hypolimnia, consistent with other studies of similar systems with DCLs. The co-occurrence of the metal-oxidizing bacteria Leptothrix spp. and bactivorous flagellates within the metalimnetic DCLs suggests that the microbial loop plays an important role in recycling nutrients within these layers, particularly phosphate (PO4) and iron (Fe). Samples taken through the water column in both embayments showed measurable concentrations of the cyanobacterial toxins microcystins (max. 0.4 µg/L) and the other bioactive metabolites anabaenopeptins (max. ~7 µg/L) and cyanopeptolins (max. 1 ng/L), along with the corresponding genes (max. in 2018). These oligopeptides are known to act as metabolic inhibitors (e.g., in chemical defence against grazers, parasites) and allow a competitive advantage. In TMB, the 2018 peaks in these oligopeptides and genes coincided with the P. cf. isothrix DCLs, suggesting this species as the main source. Our data indicate that intersecting physicochemical gradients of light and nutrient-enriched hypoxic hypolimnia are key factors in supporting DCLs in TMB and SB. Microbial activity and allelopathy may also influence DCL community structure and function, and require further investigation, particularly related to the dominance of potentially toxigenic species such as P. cf. isothrix.

Chemical limnology of Georgian Bay and the North Channel between 1974 and 1980

Hydrobiologia ◽  
1988 ◽  
Vol 163 (1) ◽  
pp. 77-83 ◽  
Author(s):  
R. R. Weiler
Keyword(s):  
Georgian Bay ◽  
The North
Sign in / Sign up

Export Citation Format

Share Document