Exploring the microzooplankton-ichthyoplankton link: a combined field and modeling study of Atlantic herring (Clupea harengus) in the Irish Sea

Authored by Myron A Peck, Marc Hufnagl, Franziska Bils, Marta Moyano, Nicole Aberle, Santiago Alvarez-Fernandez

Date Published: 2017

DOI: 10.1093/plankt/fbw074

Sponsors: German Federal Ministry of Education and Research (BMBF)

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

The microzooplankton-ichthyoplankton link remains poorly resolved in field studies due to a lack of simultaneous sampling of these predators and potential prey. This study compared the abundance, distribution and growth of larval Atlantic herring (Clupea harengus) and the abundance, biomass and composition of micro-and small mesozooplankton throughout the Irish Sea in November 2012 and 2013. In contrast to warmer months, microzooplankton biomass was highest in eastern areas, in the vicinity of the main spawning grounds of herring. Although the protozoan composition differed somewhat between years, dinoflagellates (e.g. Gymnodinium spp., Protoperidinium spp., Ceratium furca) dominated in abundance and/or biomass, similar to other temperate shelf seas in autumn/winter. Spatial differences in the protozoan community were strongly related to hydrographic characteristics (temperature, salinity). Significant relationships between the abundance of larval herring and dinoflagellates (positive) and copepodites (negative) suggested that complex grazing dynamics existed among lower trophic levels. When different, in situ size fractions of zooplankton were used as prey in a larval herring individual-based model, simulations that omitted protozooplankton under-predicted observed (biochemically-based) growth of 8-18 mm larvae. This study suggests that small planktonic organisms (20-300 mu m) should be routinely surveyed to better understand factors affecting larval fish feeding, growth and survival.

Tags

Individual-based model zooplankton growth Prey Life-history North-sea Larval fish Rna/dna ratios Annual cycle 1st food Protists Autumn-spawning herring Protozooplankton community Microzooplankton-ichthyoplankton link