Applied and theoretical considerations for constructing spatially explicit individual-based models of marine larval fish that include multiple trophic levels
Authored by S Hinckley, BA Megrey, AJ Hermann, JM Napp
Date Published: 2001
DOI: 10.1006/jmsc.2001.1087
Sponsors:
United States National Oceanic and Atmospheric Administration (NOAA)
Platforms:
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Model Documentation:
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Abstract
Individual-based modelling (IBM) techniques offer many advantages for
spatially explicit modelling of marine fish early life history. However, computationally efficient methods are needed for incorporating spatially
explicit circulation and prey dynamics into IBMs. Models of
nutrient-phytoplankton-zooplankton (NPZ) dynamics have traditionally
been formulated in an Eulerian (fixed spatial grid) framework, as
opposed to the pseudo-Lagrangian (individual-following) framework of
some IBMs. We describe our recent linkage of three models for the
western Gulf of Alaska: (1) a three-dimensional, eddy-resolving, wind-
and runoff-driven circulation model, (2) a probabilistic IBM of growth
and mortality for egg and larval stages of walleye pollock (Theragra
chalcogramma), and (3) an Eulerian, stage-structured NPZ model which
specifies production of larval Pollock prey items. Individual fish in
the IBM are tracked through space using daily velocity fields generated
from the hydrodynamic model, along with self-directed vertical
migrations of Pollock appropriate to each life stage. The NPZ dynamics
are driven by the same velocity, temperature. and salinity fields as the
pollock IBM, and provide spatially and temporally varying prey fields to
that model. The resulting prey fields yield greater variance of
individual fish attributes (e.g. length), relative to models with
spatially uniform prey, Practical issues addressed include the proper
time filtering and storage of circulation model output for subsequent
use by biological models, and use of different spatial grids for
physical and biological dynamics. We demonstrate the feasibility and
computational costs of our coupled approach using specific examples from
the western Gulf of Alaska.
Tags
Early-life history
Theragra-chalcogramma
Walleye pollock
Pacific-ocean
Shelikof-strait
Mixed-layer
Eddy-resolving model
Of-alaska shelf
Fisheries oceanography
Standing stock