At the PICES Thirteenth Annual Meeting (October 2004, Honolulu, U.S.A.),
Dr. William Peterson (Hatfield Marine Science Center, NMFS, U.S.A.) submitted
a proposal entitled International “Year of the euphausiid”
study: Comparative life history of euphausiids in continental shelf and
slope waters around the Pacific Rim. The idea was for PICES scientists
to add euphausiid sampling and live euphausiid experiments to their current
research efforts. The following highlights the importance for comparative
studies of euphausiids:
||Euphausiids are among the most important
links in coastal and oceanic food webs, transferring energy from primary
and secondary producers to higher trophic level animals such as salmon,
herring, sardines, mackerel, Pacific whiting, sablefish, many rockfish
species, auklets, shearwaters and whales.
||Given their importance in the food chain, euphausiids
may be considered keystone sentinel organisms.
||We have very little information on the seasonal cycles
of abundance, feeding, reproduction or growth rates of these animals.
Comparative studies are needed to understand their trophic status
and how climate change may affect their population dynamics.
||Given that many scientists within PICES have made great
progress in applying NEMURO and ECOSIM models to the study of ecosystem
dynamics, PICES scientists would benefit greatly from increased efforts
to provide better estimates of euphausiid biomass and vital rates
so as to properly parameterize the euphausiid component of these models.
Improvements to the models will result in a tool that will allow us
to investigate quantitatively the role of euphausiids in food chain
||PICES scientists are uniquely capable of increasing
our understanding of euphausiids because many oceanographic stations
and monitoring lines are routinely sampled for hydrography and zooplankton.
PICES scientists could easily incorporate sampling of euphausiids
into these existing monitoring programs (by sampling at night) and,
with some instructions and basic supplies, could learn how to collect
living animals at night to make measurements of reproduction, molting
and growth rates.
||One species of euphausiids, Euphausia pacifica,
is of special interest. This species ranges from the cool upwelling
regions off Mexico, north through the waters of California, Oregon,
Washington and British Columbia, into the downwelling environment
of the Gulf of Alaska, and across the Pacific in the Transition Zone,
then south through the western Pacific from Russia to China. In the
western Pacific this species inhabits waters where temperatures range
from sub-arctic to sub-tropical (the Oyashio, the Kuroshiro, the Japan/East
Sea, and the East China and Yellow Seas). There are few species that
occupy such a wide variety of ecosystems and such a wide range of
latitudes. Thus, we ask, “What are the unique characteristics
of the life history of this cosmopolitan euphausiid species that allows
it not only to populate but dominate such a wide variety of ecosystems?”
||How do populations in the eastern
and western Pacific respond to ENSO and PDO cycles?
||How do individuals manage to survive year-around
in the very warm water regions of the Yellow Sea, East China
Sea and Japan/East Sea?
||How do individuals deal with low primary production
in winter in the Northern California Current, Gulf of Alaska
and Transition Zone?
|In addition to studies of Euphausia
pacifica, members of the genus Thysanoessa are key components
of coastal systems in cooler regions around the Pacific Rim and should
be included in comparative studies.
To make the idea of comparative studies a reality, written protocols
are needed in order to standardize sampling and experimental methods among
researchers. The posted document is intended to serve this purpose. The
document is the updated version of the protocols distributed to euphausiid
researchers at the PICES Fourteenth Annual Meeting (October 2005, Vladivostok,
Russia). Our lab at the Hatfield Marine Science Center (Newport, Oregon,
U.S.A.) has used and refined these protocols over a period of five years.
We have an extensive data set of growth rate and egg production measurements
for Euphausia pacifica in the eastern North Pacific, off the
coasts of Oregon and Washington. We are very excited at the prospect of
expanding this data set to encompass the entire North Pacific.
We also suggest that scientists interested in comparative studies of
euphausiids meet at the PICES Fifteenth Annual Meeting (October 2006,
Yokohama, Japan) to discuss the feasibility of establishing a Working
Group on Euphausiids.