Laboratory studies of ingestion and food utilization in lobate and tentaculate ctenophores 1

Abstract

Ctenophore ingestion rates are linearly related to food density up to concentrations much higher than those usually assumed to be representative of the natural environment. Daily rations in excess of l,OOO% of their body weights at high prey densities are matched by growth rates characteristic of phytoplankton (daily doublings). Digestive efficiencies >70% were recorded at moderate prey densities. Growth efficiencies rarely exceed 10% bccausc the bulk of assimilated food (up to 80% of that ingested) is required for the energy metabolism of these organically dilute (carbon 2% of dry wt) creatures.

Predation efficiency in visual and tactile zooplanktivores

“…Thus, the feeding rate of B. infundibulum also reached satiation. This phenomenon has been observed for lobate ctenophores in previous studies (Reeve and Walter 1978;Kremer 1979) but has seldom been recognized for its importance in, for example, energy budgets.…”

“…2 and 3). It is a common feature for ctenophores to obtain linear predation rates (Reeve and Walter 1978). However, at high prey densities, prey are killed but not eaten by B. infundibulum.…”

Seasonal refugia, shoreward thermal amplification, and metapopulation dynamics of the ctenophore Mnemiopsis leidyi in Narragansett Bay, Rhode Island

“…Before reaching these temperatures, pulses likely were ephemeral because the thermal physiology of M. leidyi constrains reproductive potential and the ctenophores had no mechanism for population replacement to counter advective losses caused by high average flushing rates in Narragansett Bay (Pilson 1985). Once temperature limitation was relaxed by spring warming throughout the bay, the dramatic feeding (Reeve et al 1978;Kremer 1979) and reproductive capacities (Kremer 1975;Sullivan unpubl. data) of M. leidyi allowed rapid colonization and population expansion throughout the bay.…”

“…The importance of Mnemiopsis leidyi as a planktonic predator has been documented by a large body of research on its feeding capabilities (Kremer 1975;Reeve et al 1978;Waggett and Costello 1999) and trophic impacts (Kremer 1979;Shiganova et al 2001;Sullivan et al 2001). These predatory capabilities underlie the importance of recent range expansion patterns for M. leidyi.…”

“…We propose that earlier occurrences of M. leidyi during recent years are due to amplification of pulsed spring warming events that permit early reproduction in the shallow embayments that serve as source regions for M. leidyi in Narragansett Bay. We further suggest that the source-sink perspective we describe is relevant not only to Narragansett Bay but other temperate regions of the world persistently occupied by M. leidyi.The importance of Mnemiopsis leidyi as a planktonic predator has been documented by a large body of research on its feeding capabilities (Kremer 1975;Reeve et al 1978;Waggett and Costello 1999) and trophic impacts (Kremer 1979;Shiganova et al 2001;Sullivan et al 2001). These predatory capabilities underlie the importance of recent range expansion patterns for M. leidyi.…”