Population dynamics and zooplankton-predation impact of the indigenous scyphozoan Aurelia aurita and the invasive ctenophore Mnemiopsis leidyi in Limfjorden (Denmark)

Abstract

The invasive ctenophore, Mnemiopsis leidyi, which had its first mass occurrence in Limfjorden (Denmark) . During that period, copepods and other mesozooplankton organisms were virtually absent while ciliates were a substantial part of the zooplankton biomass. In "pre-Mnemiopsis years", there seems to have been large variability in the grazing impact on zooplankton depending on the seasonal abundance of A. aurita. With the addition of the second carnivore M. leidyi, however, additional predation pressure caused the zooplankton stocks to be severely depressed throughout 2008 and 2009 when copepods and cladocerans no longer showed the high seasonal peaks in abundance typical of previous years.

Abundance, seasonal patterns and diet of the non-native jellyfish Blackfordia virginica in a Portuguese estuary

“…13 Riisgård et al, 2012), compete with other zooplanktivorous species, including fishes (Purcell & Arai, 2001) and have a direct impact on fish stocks by feeding on fish larvae and eggs (Purcell, 1985). In the present study, the majority of B. virginica medusae did not have zooplankton prey in the guts (89.4% vacuity index).…”

Effect of neurotoxic compounds on ephyrae of Aurelia aurita jellyfish

“…in coastal areas (Purcell et al, 2001(Purcell et al, , 2007. Nowadays, it is extensively accepted that gelatinous zooplankton are key components of marine food web both as major predators of metazooplankton (Purcell, 1997;Riisgard et al, 2011) and as prey of apex predators, such as tuna, billfish, sunfish, and sea turtles (Arai, 2005;Cardona et al, 2012). In addition, increasing evidence has shown that gelatinous zooplankton influence the microbial food web, through direct and indirect effects, besides regulating the marine biogeochemical fluxes (Pitt et al, 2005;Turk et al, 2008).…”

Top-Down Impacts of Sea Nettles (Chrysaora quinquecirrha) on Pelagic Community Structure in Barnegat Bay, New Jersey, U.S.A.

“…Specifically, in the Black Sea M. leidyi has caused rapid community shifts and depletion of fish stocks (Oguz and Gilbert, 2007). More recently, their proliferation in the North and Baltic seas has generated substantial research into the potential top-down and competitive structuring forces in pelagic food webs (Hosia and Titelman, 2011;Javidpour et al, 2009;Kellnreitner et al, 2013; but see Hamer, Malzahn, and Boersma, 2011;Jaspers et al, 2011) and species interactions between M. leidyi and other gelatinous zooplankton species (Riisgård, Barth-Jensen, and Madsen., 2010;Riisgård et al, 2012). Within its native range, M. leidyi has always played an important role in pelagic food webs (Deason and Smayda, 1982;Mountford, 1980;Nelson, 1925), but with increasing anthropogenic stresses related to eutrophication and overfishing, their relative abundance and influence on communities has led to broader structuring effects in coastal communities (Breitburg et al, 2010;McNamara, Lonsdale, and Cerrato, 2010;.…”