Page 



The zooplankton of Western Lake Erie 200 



Introduction 200 



Pre\dnus investigations in the Great Lakes 200 



Materials and me thods 201 



Data and discussion 208 



Qualitative data 208 



Quantitative data 210 



Island Section 210 



Horizontal distribution 210 



Vertical distribution 211 



Seasonal dis tribution 212 



Season of 1928 212 



Season of 1929 2l5 



Season of 1930 219 



Comparison of seasonal distribution in 1928,1929 



and 1930 223 



Adequacy of the sampling program 226 



■"Abundance of zooplankton compared with that of other 



lakes 227 



Portage River Section 229 



Maumee Bay Section 231 



River Raisin Section 237 



Detroit River Section 238 



Comparison of abundance of zooplankton in different 



sections of Western Lake Erie 2U2 



The bottom organisms of the offshore waters of Western Lake Erie 2^9 



Introduction 2U9 



Previous investigations in the Great Lakes 2^9 



Materials and metho ds 2^0 



Criteria of pollution 252 



Acknowledgments 256 



Data and discussion 256 



Qualitative data 256 



Organisms taken in quantitative dredges 256 



Organisms taken in bottom sled 258 



Quantitative data 259 



Island Section 259 



Abundance of bottom organisms 259 



Weight of organisms 266 



Portage River Section 267 



Maumee Bay Section 267 



Regular stations 267 



Extent of pollution out from the mouth of Maiimee River. 273 



Pollution near the entrance to Toledo Harbor 275 



Summary statement regarding pollution in the Maumee 



Bay Section 281 



River Raisin Section 282 



Station 117 282 



Extent of pollution out from mouth of River Raisin... 28U 



