Effects of the 1997-1998 El Niño on early-juvenile Pacific hake Merluccius productus: Age, growth, abundance, and diet in coastal nursery habitats

Abstract

The effects of anomalous oceanographic conditions on growth, abundance, spawn-date distributions, and diet of early-juvenile Pacific hake Merluccius productus were examined in nursery grounds off the coast of central California, USA. Spring collections from 2 consecutive years of El Niño conditions, 1997 and 1998, 1 year of La Niña conditions, 1999, and 1 non-anomalous year, 1995, were examined. During spring of 1997, the first year of the El Niño event, early-juvenile hake appeared to compensate for anomalous ocean conditions by ingesting a wider variety of zooplankton taxa and sizes. Continuation of El Niño conditions through spring 1998 appeared to have a strong impact on the 1998 year class. Very low levels of macrozooplankton biomass in February 1998 resulted in poor growth and reduced survival of hake from early spawns.