Invasive ctenophore Mnemiopsis leidyi in Norway

Abstract

We present data on the occurrence of the invasive ctenophore Mnemiopsis leidyi in Norway after the initial observations made in 2005. Our data comes from several net sampling investigations conducted along the Norwegian coast in 2008-2014, as well as beach seine bycatch from the south coast (September -October 2005. In 2008-2010, M. leidyi occurred in moderate abundances (≤0.56 lobate ind m 23 ) during autumn, with northernmost observations from Trondheimsfjord. Mnemiopsis leidyi was not observed in 2011 -2012 and was scarce in 2013, but in 2014 it was again abundant along the south and west coasts. While temperature and salinity conditions along the Norwegian south coast and its fjords are sufficient for survival and reproduction by M. leidyi, temperature may limit egg production rates. Biological factors including food limitation as well as competition and predation by native gelatinous predators can also constrain populations. Mnemiopsis leidyi populations in Norway are likely to exhibit source-sink dynamics, with advective losses and suboptimal conditions preventing overwintering in large areas along the coast. The presence of M. leidyi in the southern North Sea, coupled with the cyclonic circulation pattern, suggests that outbreaks may nevertheless be expected in years with favourable conditions and/or significant inflow from the southern North Sea. Climate change could enhance reproduction of M. leidyi in Norway and protected inner fjords may offer a suitable habitat for establishment of local populations in the future.

Patterns of invasive ctenophore Mnemiopsis leidyi distribution and variability in different recipient environments of the Eurasian seas: A review

“…In other regions of Norway, M. leidyi was recorded in Oslofjord (September-October 2010), along the southern Norwegian coast and northward from Bergen up to Trondheimsfjord (2009-2012) (Fig. 7) (Hosia et al, 2013). Our analysis of M.leidyi distribution and current patterns allow assuming that Swedish coast population could be a source for M.leidyi dispersal along the Norwegian western coast.…”

“…We assess the patterns of M. leidyi distribution in all known recipient areas to analyze its seasonal and interannual variability and to identify its potential for continued expansion in new habitats. Pereladov, 1988;Vinogradov et al, 1989;Mutlu, 1999;Studenikina et al, 1991;Mirsoyan et al, 2006;Shiganova et al, 2001A;Shiganova, 1993;Shiganova & Malej, 2009;Galil et al, 2009;Boero et al, 2009;Lilley et al, 2014;Fuentes et al, 2010;Marambio et al, 2013;Javidpour et al, 2006;Boersma et al, 2007;Faasse & Bayha, 2006;Hansson, 2006;Oliveira, 2007;Tendal et al, 2007;Van Ginderdeuren et al, 2012;Antajan et al, 2014;Hosia & Falkenhaug, 2013;Delpy et al, 2012;Cruz et a.,2018;Zaghloul et al, in press).…”

Selection for life‐history traits to maximize population growth in an invasive marine species

“…100 generations after establishment in southern and northern Europe, respectively, populations in the invasive realm remain selected for opportunistic traits. The dynamic nature of marine environments along with multiple reinvasions (Ghabooli et al., ; Reusch et al., ) and a constantly moving range expansion front in northern Europe (Hosia & Falkenhaug, ) may explain sustained invasive traits in western Eurasian populations of M. leidyi , despite the long time since the species was first recorded. As connectivity is much higher in the marine realm compared to near shore, terrestrial, or fresh water systems (Kinlan & Gaines, ), density dependence might be temporarily and spatially offset.…”

Assessing the Value of a Citizen Science Approach for Ctenophore Identification

“…Scientific literature contains relatively few mentions of ctenophores from Norway, let alone specific species found in the region. So far, baseline data on species richness, diversity and distribution patterns of ctenophores are lacking (see e.g., Hosia and Falkenhaug, 2015;Johansson et al, 2018;Majaneva et al, 2021;Shiganova and Abyzova, 2021). The aim of this study was to target this knowledge gap by mapping the pelagic ctenophore diversity along the Norwegian coast from the North Sea to Svalbard.…”