Organic matter and elemental composition of gelatinous and soft-bodied zooplankton in the Northeast Pacific

Gelatinous and soft-bodied zooplankton (GZ) have long been considered to have low energetic value and are insufficient to sustain higher trophic levels. However, the nutritional composition of GZ is often poorly known for entire groups, ignoring species-, size- and stage-specific differences. Organic matter and elemental composition (carbon and nitrogen) were measured for more than 1000 specimens from 34 GZ species collected in the Northeast Pacific between 2014-2020 using a variety of nets (CanTrawl250, Bongo net, Juday net, Multinet Medi, Dip net, Midwater trawl, Neuston net). Size-dependent variability was shown for several species. Differences in organic content and elemental composition by development stage were observed in a salp and scyphomedusa species, highlighting the need to consider life cycle stages separately.