The quick and the dead: copepods dominate as cladocerans decline following invasion by Hemimysis anomala

Abstract

The North American invasion of a non-native mysid, Hemimysis anomala, has been expanding since 2006, with the first inland lake invasions detected for Oneida Lake in 2009 and Seneca Lake in 2010. Although we know that Hemimysis primarily consumes zooplankton, our ability to predict the community-level impact of an invasion is hampered by a lack of information on taxon-specific effects. To investigate the effects of Hemimysis on native zooplankton, we conducted two mesocosm experiments that compared composition between communities with and without Hemimysis and studied how the effects of this predator on zooplankton species composition varied across a natural gradient of low to high invader densities (0.01–0.1 individuals·L−1). Our first experiment found that Hemimysis primarily affected cladocerans, and particularly Daphnia, shifting communities towards dominance by copepods. Our second experiment showed that Hemimysis invasions may do little to suppress Daphnia abundances until between 0.067–0.11 individuals·L−1 or higher. Cladocerans are important links in freshwater trophic transfer and the nutrient cycle, and disruption of these linkages following Hemimysis invasion could result in both bottom-up and top-down impacts in nearshore food webs. However, Hemimysis can also fill a similar trophic role as the zooplankton they consume, and longer-term experiments are required to better assess their eventual impacts on native communities.

WITHDRAWN: The Ecological Biases of Zooplankton Invasions: Taxonomic, Geographical And Methodological Perspectives

“…The fact is that geographic and taxonomic biases are linked. Although the distributions of the most studied species are not native, they persist and establish themselves in new regions as part of the trophic web (Sinclair et al 2016), one of their invasive characteristics. Thus, it is evident that studies carried out in these regions will generate more data related to species already well studied (Figure 3).…”

“…(ii) The collection of information on biomass, abundance and density of species is quite frequent and uses simpler methodologies and techniques in comparison to aspects of the individual and ecosystem levels, for example. Thus, a methodological bias exists with respect to research on non-native zooplankton, where numerical data collected from individuals leads to more frequent observations of demographic effects, which could have different results at larger scales of space (Guerin et al 2018), and time (Sinclair et al 2016) or with different methodologies. This factor certainly in uences the frequency with which studies that show evidence of this type of ecological impact appear in the literature on non-native zooplankton species.…”

Redescription of Deltamysis holmquistae Bowman & Orsi, 1992 (Crustacea: Mysida: Mysidae), a mysid species new to the Atlantic Ocean with observations on the taxonomic status of Kochimysis Panampunnayil & Biju, 2007

“…The first, Praunus flexuosus (Müller, 1776), is endemic to European waters (see Wigley 1963;Ruiz et al 2011), and now is present along the Northeast US coast. The second, Hemimysis anomala Sars, 1907, from the Ponto-Caspian Region, has invaded the Great Lakes-St. Lawrence ecosystem and surrounding inland lakes (Sinclair et al 2016). But the original discovery location of D. holmquistae suggests its native range is likely Asia as hinted by Bowman & Orsi (1992).…”

Touch too much: aquatic disinfectant and steam exposure treatments can inhibit further spread of invasive bloody-red mysid shrimp Hemimysis anomala

“…The bloody-red mysid shrimp, Hemimysis anomala Sars, 1907, is a highly invasive, eurytolerant and ecosystem-destabilizing crustacean species of Ponto-Caspian origin, which has invaded European waterways and the Laurentian Great Lakes (Iacarella et al 2015;Sinclair et al 2016). Notably, H. anomala has been observed to form self-sustaining populations in wetland ecosystems, such as within the Rhine and Danube rivers deltas, which have acted as major source pools for its further spread (Audzijonyte et al 2008).…”

“…Notably, H. anomala has been observed to form self-sustaining populations in wetland ecosystems, such as within the Rhine and Danube rivers deltas, which have acted as major source pools for its further spread (Audzijonyte et al 2008). Hemimysis anomala can negatively affect populations of native zooplankton and mysid species, resulting in both bottom-up and top-down impacts in nearshore food webs (Iacarella et al 2015;Sinclair et al 2016). Here, we assessed the effectiveness of disinfectant immersion and mist-spray treatments for two commonly used aquatic disinfectants: Virasure Ò and Virkon Ò Aquatic.…”