Effect of lake-wide planktivory by the pelagic prey fish community in Lakes Michigan and Ontario

Abstract

We compared predatory demand by pelagic planktivorous prey fish with invertebrate production in Lake Michigan during 1987 and in Lake Ontario during 1990. Predation by the planktivores in Lake Ontario was nearly fourfold higher than in Lake Michigan Qapprox. 87 g wet ~e i g h t -r n -~-~e a r -' ) .Predation rates on Mysis were comparable in Lakes Michigan and Ontario (approx. 21 g-m-2-year-'), while predation on Diporeia was markedly higher in Lake Michigan than in Lake Ontario (21.3 vs. 8.5 g wet ~e i g h t . m -~.~e a r -' ) .In Lake Ontario, predatory demand on zooplankton exceeded our best estimate of production by a factor of 1.7. Similarly, predation estimates on Mysis in Lake Ontario were 1.2-2.0 times the estimated rate of production, depending on the production model used. Lake Michigan planktivores consumed approximately 55% of available zooplankton production in 1987, indicating that competition for prey resources, if operating, was not as intense as that in Lake Ontario in 1990. It is unclear how to resolve the paradox that predation could markedly exceed available prey production in some cases. There could be sources of error in the estimates of both the supply and demand sides of these trophic relationships.RCsnmC : Nous avons compare B la production d'invertCbrCs la demande predatrice des poissons pelagiques planctivores servant eux-rnemes de proies, en 1987 dans le lac Michigan et en 1990 dans le lac Ontario. Dans ce dernier lac, la prkdation par les planctivores Ctait prks de quatre fois plus ClevCe que dans le lac Michigan (environ 87 g poids frai~-rn-~.an-'). Les taux de predation 5 17&gard des Mysis 6taient comparables dans les deux lacs (environ 21 g.ms2.an-'1, tandis que la prddation i lqCgard des Diporeia etait nettement plus haute dans le lac Michigan que dans le lac Ontario (21,3 contre $ 3 g poids frai~-m-~-an-l). Dans le lac Ontario, la demande des prkdateurs i l'kgard du zooplancton dkpassait d'un facteur de 1,7 notre meilleure estimation de la production.Be meme, les estimations de la prCdation a l'kgard des Mysis dans le lac Ontario correspondait B 1,2-2,0 fois le taux estimC de production, selon le modkle de production retenu. Les planctivores du lac Michigan ont consommC environ 55% de la production disponible de zooplancton en 1987, ce qui indique que la concurrence 8 l'Cgard des ressources em proies, si elle existait, n'itait pas

Particle Transport, Nutrient Cycling, and Algal Community Structure Associated with a Major Winter-Spring Sediment Resuspension Event in Southern Lake Michigan

“…On a lake scale, it is known that the quantity and composition of phytoplankton strongly depends upon available resources (Holland and Beeton 1972, Kilham and Hecky 1988, Makulla and Sommer 1993 including light, phosphorus, silica, and nitrogen. Food quality (the composition of phytoplankton) is a major factor affecting the composition and production rates of invertebrates (pelagic and benthic) that in turn serve as prey for forage fish in coastal ecosystems (Barnhisel and Harvey 1995, Rand et al 1995, Almond et al 1996.…”

The effects of temperature and predator—prey interactions on the migration behavior and vertical distribution of Mysis relicta

“…Water was exchanged on a daily basis, but prior to the exchange, water was extracted and diluted to a concentration believed to be representative of a low and high alewife density in Lake Ontario (0.073 fish m 23 and 1 fish m 23 , respectively). Low concentration (LC) was calculated as 50% of the estimate of alewife abundance in Lake Ontario of Rand et al (1995) from the summer of 1991 (2.2 alewife m 22 equally distributed in the top 15 m of the water column, or the average depth of the epilimnion in August 1995). High concentration (HC) was set to 14 times higher than low concentrations (1 fish m 23 ).…”

Widespread consumption-dependent systematic error in fish bioenergetics models and its implications

“…BEMs are appealing because they are based on balanced, energy-fate equations that have been thought to promote reasonable predictive behavior. These models have been widely used to evaluate factors that constrain fish growth (Hayward and Margraf 1987;Hill and Magnuson 1990), impacts of fish predation on prey populations (Jones et al 1993;Rand et al 1995;Kershner et al 1999), contaminant bioaccumulation in fishes (Jackson 1996), and waste loads from aquaculture (Axler et al 1994). They have also been applied to enhance understanding of basic ecological processes such as the role of fish in lake nutrient cycling (Schindler and Eby 1997), and commonly serve as subcomponents of individual-based models of fish life history and population dynamics (Trebitz 1991;Rose and Cowan 1993) and other model types (Hayes et al 2000;Burke and Rice 2002).…”