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Continuous Plankton
Recorder
WHY ARE WE SAMPLING?
WHO WE ARE
Principal Investigators
Sonia Batten
Sir Alister Hardy Foundation for
Ocean Sciences
[email protected]
Plankton are the base of every marine food chain. Many of the important
species (including herring, salmon, birds and marine mammals) that live in
Prince William Sound also seek food outside of the Sound for at least some
part of their life cycle. An understanding of the productivity within these
continental shelf and offshore areas is therefore important to our overall
understanding and predictions of fluctuations in the abundance of animals
that depend on the resources over this larger area. The objective of the
Continuous Plankton Recorder (CPR) project is to opportunistically sample
plankton from ships transiting the Gulf of Alaska. These “vessels of opportunity” are not research vessels, but carry CPR instrumentation as they transit.
Data about the abundance and biomass of different types of plankton has
been collected in this way and summarized and analyzed on a monthly basis
during spring and summer seasons beginning in 2000. This information is
important in helping us understand factors that may be causing changes
within the ecosystem both across time and within different regions.
WHERE ARE WE SAMPLING?
The current path that is sampled includes the inner part of Cook Inlet, onto the
open continental shelf and across the shelf break into the open Gulf of Alaska.
Location of the samples collected along the CPR transect (red dots) and the Seward Line stations (+).
www.gulfwatchalaska.org
[email protected]
HOW ARE WE SAMPLING?
The cargo vessel Horizon Kodiak tows a
Continuous Plankton Recorder (CPR, pictured)
northbound towards Cook Inlet approximately once per month between April and
September each year. The samples are
unloaded and the gear serviced each time by
Alaskan technicians who have been trained by
Sir Alister Hardy Foundation Ocean Sciences
(SAHFOS). Sample processing is carried out
A continuous plankton recorder is lowered into the
at the Department of Fisheries and Oceans
ocean to be towed behind a cargo ship.
laboratory in Sidney, British Columbia, and at
the SAHFOS laboratory.
The Horizon Kodiak is currently the
vessel of opportunity that tows the
Continuous Plankton Recorder across
the Gulf of Alaska.
The North Pacific CPR
WHAT ARE WE FINDING?
program is funded through a
The graphs below show monthly data for the shelf region and into Cook Inlet
from 2013. The abundance of diatoms peaked strongly in May and again in
September which is the typical pattern. Otherwise, their monthly abundance
values were slightly lower than average, but within the range seen previously.
Estimated mesozooplankton biomass was generally lower than average until
September. In contrast, zooplankton abundance was quite high in June and
September. Low biomass and relatively high abundance suggests a dominance
of smaller species at these times.
consortium managed by the
North Pacific Marine Science
organization, PICES. Vessels of
opportunity will tow the CPRs
along various shipping tracks
so that the data are consistent
and have a long time-scale
over which they are collected.
Copepods are important food sources for many
animals including seabirds, and juvenile salmon.
Copepod size, species and abundance information
collected by the continuous plankton recorder helps
scientists understand the environmental conditions
that contribute to the variability in the Gulf of Alaska
ecosystems.
Results from 2013 CPR sampling. Monthly means are overlaid
on the long time series of CPR observations from the Alaskan
Shelf/Cook Inlet region. Upper graph shows mean diatom
abundance (top), lower graphs show zooplankton biomass
(middle) and abundance (bottom).
www.gulfwatchalaska.org
[email protected]