Infestation with larvae of the sea anemone Edwardsia lineata affects nutrition and growth of the ctenophore Mnemiopsis leidyi

Abstract

SUMMARYThe lobate ctenophore Mnemiopsis leidyi is a periodically abundant and voracious plankton predator in coastal waters along the east coast of the United States. In the 1980s it was accidentally introduced to the Black Sea where it caused a dramatic reduction in fisheries. We investigated how M. leidyi is affected by infestation with parasitic larvae of the sea anemone Edwardsia lineata. Infested M. leidyi contained 1–30 (median 7) E. lineata larvae. Within M. leidyi most larvae had their mouth in the gastrovascular system near the aboral end of the pharynx. Parasitic E. lineata ingested all food previously ingested and pre-digested by M. leidyi. Non-infested M. leidyi had higher growth rates than infested individuals, which had zero or negative growth rates. Egg production was similar for infested and non-infested M. leidyi of similar size. Simulation based on the empirical data suggests that growing, non-infested, M. leidyi are expected to have a larger life-time egg production than infested shrinking individuals. E. lineata could be at least partially responsible for the sharp decline of M. leidyi populations in fall in US coastal waters. Advantages and disadvantages of E. lineata as a potential candidate for the control of the artificially introduced M. leidyi population in the Black Sea are discussed.

Parasitic anemone infects the invasive ctenophore Mnemiopsis leidyi in the North East Atlantic

“…In the native habitat of the ctenophore, parasitic infections from the sea anemone Edwardsiella lineata are common and parasitized Mnemiopsis have significantly lower, sometimes negative growth rates. Prevalence can be higher than 50% (Crowell 1976;Reitzel et al 2007) and as a consequence parasite infection may be one of the factors that contribute to population control (Bumann and Puls 1996). Here we report of the first occurrence of parasitic sea anemone larvae in M. leidyi from the NE Atlantic, together with densities of the parasite and the host ctenophore during 2007 and 2008.…”

“…Furthermore, B. ovata had smaller E. lineata parasites that required longer time to metamorphose compared to parasites from Mnemiopsis (Reitzel et al 2007). It is likely that the occurrence of E. lineata in B. ovata is a case of incidental transmission rather than true parasitism (Bumann and Puls 1996). Nevertheless, it can not be excluded that E. lineata may parasitize some of the native ctenophores in the Skagerrak, and it would be desirable to find out if the local species of ctenophores; Bolinopsis infundibulum, Beroe cucumis.…”

“…On one hand, Bumann & Puls (Bumann and Puls 1996) found that the growth rate decrease, often to negative values in infected Mnemiopsis. Parasite infection had no detectable direct effect on fecundity, but due to the relationship between size and fecundity in Mnemiopsis, Buman and Puls calculated *50% decrease in fecundity of infected Mnemiopsis after 2 days of infection and *80% decrease after 7 days of infection compared to uninfected individuals.…”

Symbionts of marine medusae and ctenophores

“…After the parasite assumes a spherical, planula-like shape, and exits the host, it reinfects another host or settles as a polyp. The endoparasite absorbs nutrients from the host, leading to its starvation and a reduction in fecundity (Bumann & Puls 1996). Both small-and large-sized parasitized individuals showed significantly lower growth rates than did non-parasitized ones even after only a short period, 20 hours ( Fig.…”

“…3C). Bumann & Puls (1996) implied that this parasite might be the only parasite affecting the host populations. Reitzel et al (2007) have intensively investigated the infection of the parasitic stage of E. lineata on three species of ctenophores off Wood Hole on the coast of the northern Atlantic during summer and early winter.…”