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Sea, land, river

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Community

For earlier materials see Table of Contents

Climate Change?	Or ‘Regime shifts’?
	Or ‘we don’t know’?

While sockeye strongest a decade ago – much of the variation on above graph of Gulf of Alaska regions is due to pink salmon
Source PDF --

Skeena River sockeye catch

Here I have taken out the years that are on the 2008 catch cycle --- Four years ago (2004) the sockeye return was dismal – thus the caution 2008 being treated with BUT---

2006 returns already were showing a good ‘rebound’

Part of the problem in 2006 was the fish showed up ‘late’ at the mouth of the Skeena --- but it would have taken a real optimist to predict such a strong return looking back at 1998 and 2002

Similar late returns and expectation of 2.4M fish in 2007 (but data not available in IPSR format so won’t use for fear of compatibility data)

Part of ‘explanation’ is that 2005 was an El Nino year – but the waters have become steadily cooler (more productive?) off our coast since then (and the sockeye runs returning to recent historical averages – as at left) – question is will it continue?

	2008 looks like on cycle of most productive recent times
	With 1996 best year from this series – 1988 and 1992 also strong --- so looks like the genetics there for good run – the ‘ocean conditions’ being biggest remaining question – presumably why 2002 so small

Whatever the ‘cause’ OCP is not ‘constant’ from year to year

Above the PDO shifts seem to ‘explain some intervals like 1978-’88 for the 100-150M deep waters – (maybe)
Source of figure PICES PDF

Ocean Conditions and regime shifts

Almost every ‘expert’ has a different idea – some deny existence of ‘Regimes’ like PDO (Pacific Decadal Oscillation) etc – while others place great value in them (but useful mainly in hind sight)

At left is a series of actual measurements temperatures made at Ocean Station Papa (OCP) off BC coast – for last 30 years – I have put in the dotted lines --- clear break 1977-78, but the 1999 ‘break’ debatable --- something is going on – but not clear what or what the biological implications are –

BC salmon catch in decline

Overall trend is for more salmon in N Pacific

I will return to this tomorrow

http://www.pices.int/publications/presentations/PICES_13/PICES_13_S9/Crawford_S9.pdf

PICES 2005 Marine Ecosystems of the North Pacific

Created by LG on 24/6/2008

Last updated on Tuesday, June 24, 2008

NATURE

PEOPLES

For earlier materials see Table of Contents

Or ‘Regime shifts’?

BC salmon catch in decline