Evaluating dispersal potential of an invasive fish by the use of aerobic scope and osmoregulation capacity

Abstract

Non-indigenous species (NIS) can impact marine biodiversity and ecosystem structure and function. Once introduced into a new region, secondary dispersal is limited by the physiology of the organism in relation to the ambient environment and by complex interactions between a suite of ecological factors such as presence of predators, competitors, and parasites. Early prediction of dispersal potential and future ‘area of impact’ is challenging, but also a great asset in taking appropriate management actions. Aerobic scope (AS) in fish has been linked to various fitness-related parameters, and may be valuable in determining dispersal potential of aquatic invasive species in novel environments. Round goby, Neogobius melanostomus, one of the most wide-ranging invasive fish species in Europe and North America, currently thrives in brackish and fresh water, but its ability to survive in high salinity waters is unknown to date. We show that AS in round goby is reduced by 30% and blood plasma osmolality increased (indicating reduced capacity for osmoregulation) at salinities approaching oceanic conditions, following slow ramping (5 PSU per week) and subsequent long-term acclimation to salinities ranging between 0 and 30 PSU (8 days at final treatment salinities before blood plasma osmolality measurements, 12–20 additional days before respirometry). Survival was also reduced at the highest salinities yet a significant proportion (61%) of the fish survived at 30 PSU. Reduced physiological performance at the highest salinities may affect growth and competitive ability under oceanic conditions, but to what extent reduced AS and osmoregulatory capacity will slow the current 30 km year-1 rate of advance of the species through the steep salinity gradient from the brackish Baltic Sea and into the oceanic North Sea remains speculative. An unintended natural experiment is in progress to test whether the rate of advance slows down. At the current rate of advance the species will reach the oceanic North Sea by 2018/2019, therefore time for taking preventative action is short.

Using acoustic telemetry and snorkel surveys to study diel activity and seasonal migration of round goby (Neogobius melanostomus) in an estuary of the Western Baltic Sea

“…Thriving in brackish and fresh water (Demchenko & Tkachenko, ), it has been speculated that high salinity provides a dispersal barrier for the species as it approaches the North Sea (Kornis et al., ). Yet, a study revealed that slow acclimation to increasing salinities enables high survival of adults and only marginally reduces physiological performance at salinities as high as 30 psu (Behrens, van Deurs & Christensen, ).…”

“…Yet, a study revealed that slow acclimation to increasing salinities enables high survival of adults and only marginally reduces physiological performance at salinities as high as 30 psu (Behrens, van Deurs & Christensen, 2017).…”

Size‐dependent predation of round goby Neogobius melanostomus on blue mussels Mytilus edulis

“…One of the most wide‐ranging invasive species of fresh‐ and brackish‐water environments is the round goby Neogobius melanostomus (Pallas) (Kornis, Mercado‐Silva, & Vander Zanden, ) . Originating from the Ponto–Caspian region, the round goby is a highly successful invader of novel environments (Behrens, van Deurs, & Christensen, ; Nurkse, Kotta, Orav‐Kotta, & Ojaveer, ), with established populations in the North American Great Lakes, the Baltic Sea and many European rivers (Jude, Reider, & Smith, ; Azour et al, ; Buřič, Bláha, Kouba & Drozd, ; Kotta, Nurkse, Puntila, & Ojaveer, ). The round goby feeds heavily on bivalves, both in its native (Skazkina & Kostyuchenko, ) and invaded ranges (Järv, Kotta, Kotta, & Raid, ; Raby, Gutowsky, & Fox, ).…”

Evolved for success in novel environments: The round goby genome

“…for unperturbed osmoregulation(Behrens et al 2017). However, the round goby's repertoire of key-719 genes in myo-inositol production and accumulation might bestow the species with the potential to 720 eventually tolerate higher salinities, for example through the evolution of altered gene regulation 721 patterns, and colonize higher PSUs.…”