E Brunton confirmed identifications of euphausiids
, and EL Bousfield and CT Shih identified the amphipods.
High abundance Pacific hake schools were often close to high abundance euphausiid
patches when these aggregations were close to the shelf-break, but this pattern of overlap was far less obvious along portions of transects further offshore.
Abstract: The zooplankton community structure, including copepods, euphausiids
, chaetognaths, and decapod larvae, was monitored during six circadian cycles using Bongo net (500 [micro]m mesh net) samples from Bahia Magdalena, on the southwest coast of Baja California, Mexico.
This difference in biomass is largely explained by the presence of large oceanic populations of euphausiids
(krill), which can account for more than 30% of the zooplankton biomass.
Predictor variable Type of variable Longitude Spatial Latitude Spatial Myctophid species Biological Myctophid standard length Biological Ostracod zooplankton (ZP) Biological composition Copepod ZP composition Biological Euphausiid
ZP composition Biological Zooplankton volume Biological Mixed layer depth (MLD) Oceanographic Sea surface salinity (SSS) Oceanographic Sea surface temperature (SST) Oceanographic Surface chlorophyll (SCHL) Oceanographic Predictor variable Mean (Min.
Community structure of euphausiids
and copepods in the distribution areas of pelagic fish larvae off the west coast of Baja California, Mexico.
Eight groups accounted for 95% of total abundance both in January (copepods, chaetognaths, euphausiids
, amphipods, polychaetes, pteropods, fish larvae and decapods) and May (copepods, amphipods, chaetognaths, euphausiids
, decapods, pteropods, fish larvae and gasteropods).
In the Shumagin region, the proportional weight of euphausiids
increased from 36% in LSum00 to 64% in Sum01; subsequently, in LSum01, 51% of the stomach contents were euphausiid
juveniles and adults and 40% were fish.
Vertical distribution of euphausiid
life stages in waters adjacent to Baja California.
For example, the range of euphausiid
electivity values observed may be due to the pooling of euphausiid
species and life-history stages, potentially obscuring euphausiid
prey selection patterns observed in other studies (Schabetsberger et al.
Daylight collection, and the use of a ring net, likely resulted in underestimating euphausiid
These indices are both lower than the 86% (55 of 64 whales) of bowhead stomachs that held over 50% euphausiid
contents reported by Lowry et al.