Project Summary
Mark D. Ohman and Edward G Durbin
U.S. GLOBEC: Life History Events of Calanus Finmarchicus (Copepoda)
on Georges Bank, A Component of U.S. GLOBEC: Ichthyoplankton and
Zooplankton in the Georges Bank Region
U.S. GLOBEC Phase I and II results showed that the abundance and
production rates of Calanus finmarchicus and Pseudocalanus
spp. differ
greatly between the shallow well-mixed crest waters of Georges Bank and
the deeper waters of the northeast peak and the southern flank. Dr. Ohman
and associates suggest that this smaller scale temporal and spatial variability
is controlled by variations in vital rates (recruitment, growth and mortality)
and frontal processes on GB (convergences, exchange rates across fronts).
They will address these questions through the following specific objectives:
(1) Determine spatial and temporal changes in abundance of nauplii of
Calanus, Pseudocalanus, and of other copepods on
Georges Bank during the
winter/spring period as a part of the zooplankton broad-scale survey. (2)
Determine the spatial, seasonal and inter-annual variation in egg production,
growth rates, physiological condition and mortality for the dominant copepod
species including Calanus and Pseudocalanus.
(3) Determine abundance,
individual growth rates, and physiological condition of the target copepod
species, as well as the abundance of other zooplankton species, over fine
spatial scales across the crest-southern flank tidal mixing front during late
April-early May. (4) Provide the modeling and synthesis groups with data on
copepod distribution, recruitment, growth and mortality rates. This project is
composed of four separate components which have been combined in one
proposal. These components are: (1) the broad-scale pump survey, (2) the
egg laying rate measurements of Calanus, Pseudocalanus,
and other dominant
copepods (3) the growth rate measurements of Calanus and
Pseudocalanus,
and (4) the estimation of egg and naupliar mortality of Calanus and
Pseudocalanus. The pump survey will take place during each of the broad
scale survey cruises while the latter three components will be carried out
during each of the process cruises although broad scale survey female
abundance data will be used in bank-wide egg production estimates.