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 dynamics.
- 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.