Ecology of nonnative Siberian prawn (Palaemon modestus) in the lower Snake River, Washington, USA

Abstract

We assessed the abundance, distribution, and ecology of the nonnative Siberian prawn Palaemon modestus in the lower Snake River, Washington, USA. Analysis of prawn passage abundance at three Snake River dams showed that populations are growing at exponential rates, especially at Little Goose Dam where over 464,000 prawns were collected in 2015. Monthly beam trawling during 2011-2013 provided information on prawn abundance and distribution in Lower Granite and Little Goose Reservoirs. Zero-inflated regression predicted that the probability of prawn presence increased with decreasing water velocity and increasing depth. Negative binomial models predicted higher catch rates of prawns in deeper water and in closer proximity to dams. Temporally, prawn densities decreased slightly in the summer, likely due to the mortality of older individuals, and then increased in autumn and winter with the emergence and recruitment of young of the year. Seasonal length frequencies showed that distinct juvenile and adult size classes exist throughout the year, suggesting prawns live from 1 to 2 years and may be able to reproduce multiple times during their life. Most juvenile prawns become reproductive adults in 1 year, and peak reproduction occurs from late July through October. Mean fecundity (189 eggs) and reproductive output (11.9 %) are similar to that in their native range. The current use of deep habitats by prawns likely makes them unavailable to most predators in the reservoirs. The distribution and role of Siberian prawns in the lower Snake River food web will probably continue to change as the population grows and warrants continued monitoring and investigation.

Environmental and ecological factors influencing the spillover of the non-native kelp, Undaria pinnatifida, from marinas into natural rocky reef communities

“…Zero-inflated models have commonly been used to identify environmental and ecological factors influencing the distribution-abundance patterns of rare or restricted-range aquatic species, including marine NNS (e.g. Anton et al 2014 ; Cambie et al 2017 ; Erhardt and Tiffan 2016 ; Fletcher et al 2013 ; Hoogenboom et al 2015 ). Factors affecting the distribution and abundance of Undaria at coastal sites were assessed using zero-inflated negative binomial models (ZINB, Zuur et al 2009 ).…”

Risk assessment for the reintroduction of anadromous salmonids upstream of Chief Joseph and Grand Coulee Dams, Northeastern Washington

“…In the lower Columbia River reservoirs, upstream movements of nonnative and historically estuarine invertebrates have largely followed the footprint of impoundment. For example, the Siberian prawn, Exopalaemon modestus, originally introduced in the Columbia River Estuary through barge traffic, expanded its range upstream, and is now an important component of reservoir food webs as predator and prey (Haskell and others, 2006;Erhardt and Tiffan, 2016). Similarly, the estuarine mysid, Neomysis mercedis, has extended its range into lower Columbia and Snake River reservoirs (Haskell and Stanford, 2006) and has become abundant.…”