Hobart

Seminar Abstract

Friday 4 December 2009, 11.30am (Tas time)
CSIRO Auditorium, Hobart

Anna B Neuheimer
Postdoctoral Fellow
Marine Ecology
Department of Biological Sciences
Aarhus University
Denmark

Disentangling variation in fish growth: Climate, food and fishing

Fish growth is affected by variations in a number of factors including climate (eg temperature), food consumption and fishing. The effects of these factors on resulting length-at-age variation must be disentangled to allow for the development of successful management strategies. Of the factors impacting variation in growth, temperature is a controlling factor governing growth via reaction rates at the cellular (metabolic) level and the effects of temperature on length-at-age variation must be examined foremost. Here I employ a physiologically relevant temperature metric (growing degree-days, GDD, degree Celsius d) to quantify the influence of temperature variation on length-at-age of two exploited fish populations in the northwest Atlantic (Atlantic cod, Gadus morhua, and haddock, Melanogrammus aeglefinus) where significant declines in size-at-age for mature fish are observed over the past ~ 30 years; declines that are coincident with high fishing pressure and changing environmental conditions. I explore remaining, temperature-independent length-at-age variation with information on food consumption (where available) and present evidence that remaining variation in length-at-age is consistent with sustained intensive and size-selective fishing of large (ie fast-growing and late-maturing) fish. Finally, I demonstrate that subtle changes in climate may have a large effect on fish size-at-age, something that is not easily predicted using extant fish-growth models.

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Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Clothilde Langlais, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5399
Natalie Kelly, (Biology/Modelling seminars) CSIRO Marine and Atmospheric Research 0438 452 483
Jillian Enraght-Moony, (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5320
Communications Manager, Antarctic Climate and Ecosystems CRC (03) 6226 2265
Margaret Hazelwood, Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2971

Last updated 4/12/09