You can’t tell Mother Nature what to do, so the surf didn’t quite come up as expected for Thursday or today… Weekend outlook still for 1-2 metres but dead South – means more likely in the lower part of the range – ie about 1 metre or so.
Now for the Topic de Jour – Sharks.
TG’s “Baitfish Boats on the Harbour Index” (South Head to Bradley’s)
(started 4 March 2009 – before the Professor’s letter below)… Great minds ? Anyhoo, recapping and continuing this week’s informal observations (taken at the same time each day):
Monday: 20
Tuesday: 24
Wednesday: 3
Thursday: 10
Friday: 24 (South Head to Bradley’s), plus 5 (Manly to Middle Harbour).
While the latest observation could possibly include a “seasonal” factor (being a nice sunny day; more people having a day off work starting their own long weekend?), it’s clear to me that they weren’t out there for nothing! The fish are still around. (as confirmed also by the Daily Telegraph’s front page photo).
From SMH 6 March 2009
“A surprising aspect of the recent shark attacks is what we don’t know.”…
“We don’t know if it is due to the fish bait abundance, caused by recent strong upwelling.”…
“We don’t even know the life history of bull sharks – are they just summer tourists, and if so, where do they winter? At present all such speculation needs data, and the only long-term data is the controversial shark-meshing program.”
“First, data could be sourced from reliable observers of the harbour and beaches: ferry captains, charter fishing operators and experienced observers from high-rise apartments. They could dial in an observed index from 0 to 9 which, with other data (water temperature, rainfall, upwelling), could form the basis of a weekly shark risk, similar to UV risk.”
Professor Iain Suthers Sydney Institute of Marine Science, University of NSW
Observation is the starting point for all science.
However, sometimes data observation and common sense should come ahead of detailed analysis.
Also in the papers today:
http://www.theaustralian.news.com.au/story/0,25197,25146275-5006784,00.html
“Predatory sharks have not increased in numbers, but they might be congregating in new locations with an abundance of food, according to the CSIRO’s Great White shark expert Barry Bruce.”
http://www.theaustralian.news.com.au/story/0,25197,25144508-25209,00.html
“Sharks, like all consumers, go where the market provides the most food for the easiest effort and least risk.”
TG
