Spatial and Temporal Dynamics of Invasive Freshwater Shrimp (Mysis diluviana): Long-Term Effects on Ecosystem Properties in a Large Oligotrophic Lake

Abstract

Invasion of Mysis diluviana from upstream stockings drastically altered the food web of 480 km 2 Flathead Lake, Montana (USA). Mysis increased exponentially after establishment in 1982, preying upon large zooplankters, thereby substantially altering zooplankton community composition, favoring small-sized species. In consequence, primary production increased by 21% owing to changes in zooplankton feeding efficiency. Moreover, the abundant Mysis provided forage for the nonnative lake trout that also rapidly expanded, causing concomitant extirpation of kokanee salmon and near loss of native fishes. This has become a case history of how introduced species can mediate trophic cascades. Here we examine the long-term (1982-2014) dynamics of Mysis in Flathead Lake and how distribution and abundance of this invasive species is related to chemical, physical, and biological factors. We show that Mysis is a strong interactor, regulating zooplankton and phytoplankton biomass interactively with nutrient (N and P) dynamics. Moreover, changes in life history and changing spatial dynamics are strengthening the regulatory role of the Mysis, despite seemingly strong top-down pressure via predation of the Mysis by lake trout. The Mysis are structuring nearly all interactions within and between the biota of Flathead Lake.

Impacts of freshwater aquaculture on fish communities: A whole‐ecosystem experimental approach

“…In many Ontario lakes, nutrient targets are dictated by cold water oxygen requirements for lake trout (Nelligan, Jeziorski, Rühland, Paterson, & Smol, ; Nicholls, ; Young, Winter, & Molot, ), which are a highly sought after recreational fish species across Canada and the U.S.A. (Evans, Nicholls, Allen, & McMurtry, ; Gunn & Mills, ; Gunn, Steedman, & Ryder, ). Additionally, Mysis is an important prey species to lake trout (France & Steedman, ; Trippel & Beamish, ), and Mysis abundance can greatly influence lake trout growth and life history dynamics (Devlin et al., ; Ellis et al., ; Mills, Chalanchuk, Mohr, & Davies, ). Moderate nutrient increases can have some positive impacts on the growth and condition of coldwater fish species (Lienesch, McDonald, Hershey, O'Brien, & Bettez, ; Mills & Chalanchuk, ) but potentially also long‐term negative impacts on recruitment (Lienesch et al., ).…”

Metabarcoding of native and invasive species in stomach contents of Great Lakes fishes

“…Metabarcodinging analysis of the three native prey in predator scDNA contributes to understanding the Lake Michigan offshore food web and exhibited frequencies of occurrences similar to published conventional diet analyses [i.e., 22 , 37 , 69 ]. Outside the Great Lakes, the three native prey identified in scDNA are of conservation concern [ 72 , 73 , 76 , 77 ]. Sample site, predator species, and predator TL significantly influenced AIS and native prey occurrence patterns.…”

“…The three native species were selected as we expected them to be common diet items in both native and non-native predators [ 37 , 69 ] and because they are likely to interact with the target AIS directly or indirectly [ 70 , 71 ]. Additionally, these three native invertebrate species have been reported as invasive or as posing invasion risks outside the Great Lakes [ 72 , 73 ]. BLAST analyses against the custom databases were performed using the map reads to reference function in QIIME with default parameters, except having adjusted the minimum match value to 98% for reads from the universal primer set, and having set this value to 96% as a minimum match value for reads from any of the target AIS primer sets.…”

Benthic habitat is an integral part of freshwater Mysis ecology

“…For example, estimates of Mysis consumption have generally assumed a diet of 100% zooplankton (Bunnell, Davis, Warner, Chriscinske, & Roseman, 2011;Chipps & Bennett, 2000;Gal et al, 2006;Hrycik et al, 2015;Murtaugh, 1984;Rudstam et al, 1989;Rudstam, Hansson, Johansson, & Larsson, 1992; but see Stewart & Sprules, 2011). The impact that Mysis can have on zooplankton community composition and size structure and the subsequent negative consequences for pelagic planktivorous fishes is unequivocal, as clearly seen in systems where Mysis have been introduced (Devlin et al, 2016;Lasenby et al, 1986;Nesler & Bergersen, 1991). However, estimates of Mysis zooplanktivory based on pelagic sampling, bioenergetics, and assumed consumption of 100% zooplankton will be biased high because these estimates under-represent how much benthic energy flows through Mysis, and consequently the amount of benthic energy that flows through other components of the food web that directly or indirectly interact with Mysis (Johannsson et al, 1994(Johannsson et al, , 2001Viherluoto et al, 2000).…”