Publications

Chronic studies of Daphnia Pulex exposed to different concentrations of phenanthrene, nicotine, and pinane produced consistent sublethal effects among replicates and concentrations. The LOEC's for growth and fecundity with each chemical tested were 3 to 30% of the 48-hr EC50's. Growth decreased as concentration increased for each chemical tested, and fecundity approached zero at 2 to 5...

Prey-specific anti-predatory behaviour under different degrees of structural complexity determines foraging success of predators. The behaviour of piscivorous fish (largemouth bass, Micropterus salmoides and northern pike, Esox lucius) and their prey (bluegills, Lepomis macrochirus, and fathead minnows, Pimephales promelas) were quantified in 60-min experiments in laboratory pools (2...

Interstitial water quality was measured using a submersible at seven locations on Six Fathom Bank. Historically, the bank was an important lake trout spawning ground. It is currently the focus of coordinated, interagency efforts to rehabilitate lake trout in Lake Huron. Water quality, evaluated from measurements of biochemical oxygen demand, dissolved oxygen, ammonia, and hydrogen...

Native stocks of lake trout Salvelinus namaycush were virtually or completely extirpated from the lower four Great Lakes by the early 1960s. The failure of early attempts to reestablish self-sustaining populations of lake trout was attributed partly to the practice of stocking hatcheryreared juveniles at locations and over substrates that had not been used in the past for spawning by...

We conducted surveys in 1983 and 1984 of submersed macrophyte communities off six islands in the St. Clair and Detroit rivers using low altitude aerial photography and ground-truth collections. Sample collections in 1984 followed one of the coldest winters on record, during which ice up to 4 m thick developed in areas that were normally ice-free. Growth of many of the 20 taxa collected...

In the Laurentian Great Lakes, more than 300 contaminants have been identified in fish, other biota, water, and sediment. Current hazard assessment of these chemicals by the National Fisheries Research Center-Great Lakes is based on their toxicity, occurrence in the environment, and source. Although scientists at the Center have tested over 70 chemicals with the crustacean Daphnia pulex...

My purpose here is to review historic changes in the major fish resources of the five Great Lakes, and to identify the cause or causes for those changes. In some instances it will be clear that intensive fishing was the primary cause of change; in other instances it will be nearly as clear that predation by the sea lamprey played a significant if not dominant role in change; and in still...

Sampling of benthos at 166 stations in the lower two-thirds of the St. Marys River in 1974 and 1975 yielded a total of 9 mayfly and 20 caddisfly genera. Densities of mayflies (primarily the pollution sensitive Hexagenia) ranged from 0 to more than 2,000/m2 and caddisflies (primarily Polycentropus) from 0 to 744/m2 in individual samples. No mayflies were collected in a 20 km section of...

This study demonstrates the feasibility of using low-altitude aerial photography to inventory submersed macrophytes in the connecting channels of the Great Lakes. For this purpose, we obtained aerial color transparencies and collateral ground truth information about submersed vegetation at 160 stations within four study sites in the St. Clair and Detroit rivers, September 17 to October 4...

Seasonal growth and occurrence of an exotic submersed aquatic macrophyte, Nitellopsis obtusa, was monitored at the head of the Detroit River of the Great Lakes from June 1984 to April 1985.Nitellopsis obtusa first appeared in early July, increased in biomass from July to September, remained at relatively high biomass from September to late January, and decreased substantially as ice...

Most studies of the relationships between freshwater macrophytes and phytomacrofauna, or the macroinvertebrates associated with the macrophytes, have been based on individual plant collections or samples from monotypic plant stands. We describe the phytomacrofauna assemblages within naturally occurring, taxonomically mixed stands, and consider how macrophyte surface area and plant...

A part of the connecting channel system between Lake Huron and Lake Erie, the Detroit River forms an integral link between the two lakes for both humans and biological resources such as fish, nutrients, and plant detritus. This profile summarizes existing scientific information on the ecological structure and functioning of this ecosystem. Topics include the geological history of the...