Falling productivity as a constraint on native fish abundance Where have all the fish gone? Nick Bond, Daryl Nielsen, Jim Thomson, Paul Humphries, David Crook, Jian Yen, Gavin Butler, John Koehn, David Hohnberg, Rick Stoffels, Kirk WineMiller, Paul Reich, Nicole McCasker, Mark Kennard, John Morrongiello
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Productivity and freshwater fish abundance. Jian Yen. ACEAS Grand 2014
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Falling productivity as a constraint on native fish abundanceWhere have all the fish gone?
Nick Bond, Daryl Nielsen, Jim Thomson, Paul Humphries, David Crook, Jian Yen, Gavin Butler, John Koehn, David Hohnberg, Rick Stoffels, Kirk WineMiller, Paul Reich, Nicole McCasker, Mark Kennard, John Morrongiello
Historical declines
Historical declines
OverfishingDe-snaggingClearingRiver regulationInvasive species
Historical declines
OverfishingDe-snaggingClearingRiver regulationInvasive species
A bio-energetic approach
A bio-energetic approach
What is the current carrying capacity for fish?
What limits fish abundances?
a) Less primary productivityb) Altered energy pathwaysc) Non-energetic caused) A combination of these...
We consider (a) and (b) explicitlyWhat is their importance relative to (c)?
ProductionAutochthonous (algae)~21 kg C / river km . Year
ProductionAutochthonous (algae)~21 kg C / river km . YearFloodplain production~30-100 kg C / river km . Day
ProductionAutochthonous (algae)~21 kg C / river km . YearFloodplain production~30-100 kg C / river km . DayPotentially big losses from altered flood regimes
ProductionAutochthonous (algae)~21 kg C / river km . YearFloodplain production~30-100 kg C / river km . DayPotentially big losses from altered flood regimes