Naturally spawning Chinook salmon (Oncorhynchus tshawytscha) from the effluent of a wastewater treatment plant

Chinook salmon (Oncorhynchus tshawytscha) observed spawning in the East Chicago Sanitary District Earthen Channel, East Chicago, Indiana. Lake-wide genetic variation among stocked salmonids is believed to be relatively high in this species and is reflected in the allozyme variation observed in the survey of spawning adults taken from the Earthen Channel. As an addendum to visual observation of salmon spawning and to collections in 1995 of parred juveniles within this tributary, allozyme data were obtained as a preliminary assessment of populational genetic structure. These data will form a basis for comparative studies in future years. This was the first observation and collection of parred and smelt chinook salmon from a single natural spawn in the southern basin of Lake Michigan.