"Growth and feeding of larval..."

	Growth and feeding of larval cod
	(Gadus morhua) in the Barents Sea and the Georges Bank
	Trond Kristiansen, Frode Vikebø, Svein Sundby, Geir Huse, Øyvind Fiksen, Greg Lough, Larry Buckley, and Cisco Werner

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Coupled IBM+ROMS

	Three types of models:
	A mechanistic individual-based model for simulating
	bioenergetics, behaviour, and feeding of larval cod
	A general circulation model to simulate the dynamics
	of the ocean (the ROMS model)
	A 3D zooplankton model to simulate the dynamical
	prey field

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Objectives

	Study how environmental conditions such as:
		Light
		Temperature
		Turbulence
		Food abundance
		affect growth rate of larval fish

Definitions

		Specific growth rate (SGR): the amount of weight increase over 24 hours relative to total weight
		Maximum growth: The physiologically possible growth restricted by temperature alone

"Varying light and prey availability..."

	Varying light and prey availability at two locations for two different levels of temperature, and zero turbulence.

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"Varying light and prey availability..."

	Varying light and prey availability at the two locations, and increasing temperature by 2 degrees C.

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"How do light and temperature..."

	How do light and temperature for two levels of food abundance and turbulence regulate growth of 5mm on April 1 and May 1?

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"Varying light and temperature"

	Varying light and temperature, with estimated prey distribution from the zooplankton model for larva kept fixed in space.

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"Preliminary conclusions"

	Preliminary conclusions
	Light is limiting feeding and growth prior to mid-April.
	By early May, the number of light hours increases (17/24) and growth is mainly determined by water temperature.
	High prey densities is not a requirement for growth, but may reduce the activity level of the larvae and reduce their visibility to predators.

Two important cod stocks in different habitats

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"Spawning migration"

		Spawning migration:
		Georges Bank: Short spawning migration
		Barents Sea: Very long spawning migration
	Central recruitment hypothesis:
		Barents Sea: Match-mismatch
		Georges Bank: Larval loss
		Temperature-recruitment relations:
		Georges Bank: No clear temperature-recruitment relation
		Barents Sea: Srong temperature-recruitment relationships
		Dominant prey for larvae and early juveniles
		- Georges Bank: Pseudo/Paracalanus spp.
		Barents Sea: Calanus finmarchicus
		Light, climate, spawning and larval growth:
		Georges Bank: Extended spawning period in winter/spring
		Barents Sea: Compressed spawning around equinox and rapid larval and juvenile growth thereafter

Future work

	Objectives: Use the same model setup for the Barents Sea and the Georges Bank ecosystems and model drift, dispersal, growth, feeding, survival, and behavior.
	Identify the major processes that affect survival variability between ecosystems.
	Simulate a set of years that contributed strongly to recruitment in each of the ecosystems, and try to understand the major underlying causes.
	Meet objectives using:
	- Physical model (ROMS)
	- Individual based model (IBM)
	- What about prey fields? Modeled prey fields? Theoretical prey fields? Observed prey fields?
	-  How many prey stages should be included?
	- What type of atmospheric data to use?
	- +++