Predatory impact on ichthyoplankton by Mnemiopsis leidyi (Ctenophora) is size-dependent: an experimental approach

Abstract

Understanding the size-related predatory effects of Mnemiopsis leidyi on ichthyoplankton is crucial for evaluating its effects on fish populations. This study examines the capabilityof M. leidyi to consume ichthyoplankton and assesses whether consumption of fish eggs is dependent on ctenophore size. Laboratory experiments indicated that M. leidyi (4.6–10.5 cm totallength) ingest fish eggs and larvae of Seriola lalandi. Ingested fish larvae were fully digested, whileeggs were often regurgitated undigested; however, most regurgitated eggs were non-viable. Ourresults also revealed a significant positive relationship between ctenophore size and egg ingestion.These findings suggest that M. leidyi can consume ichthyoplankton. However, the predatoryimpact that this ctenophore could exert on fish recruitment in areas where these taxa co-occur willmost likely depend on ctenophore abundance and body size.