Think twice before anchoring in seagrass.
Full write-up and photos:
blog.arribasail.com/2014/11/anchoring-in-seagrass-please-dont.html
Good reminder, it is offends in NSW.
Guess in SA Gulfs is serious issue.
Used to sail top half of Spencer Gulf, it's hard to find
place to anchor without sea grass.
With CQR anchor, there is no holding.
Later in Vic. Westernport Bay, I use small Admirality, excellent holding.
I understand that in places, such as Spencer Gulf, it can be very hard to find an anchorage that is not weedy. I just want to encourage everyone to take an extra hard look, before dropping anchor. Often there are "white holes" (existing sandy holes in the seagrass) that can be reused.
Excellent write up and we should all think long and hard about our marine environment that we rely so heavily on to enjoy not only our favourite past times but also our fish stocks, sand stability and biodiversity. In terms of real threats, lets keep this in perspective. A temporary anchor in a seagrass meadow is a very, very minor contribution to the loss of seagrass. Seagrasses shed their leaves coming into winter so raking an anchor through them will not cause the loss of a plant or meadow. I do not feel guilty in anchoring in seagrass.
A permanent chain mooring will cause significant damage and we can see evidence of this in SA. See picture below
The key threats of seagrass in SA are nutrient pollution from sewage discharges, stormwater and agricultural runoff and sea cage aquaculture (in Spencer Gulf).
In higher wave energy locations (metro SA) when we have a considerable scar in a meadow, we can get a blowout which is an expansion of the loss which with Posidonia genus seagrass is often irreversible (the grow very slowly). Beachport seagrass is an example of catastrophic seagrass loss due to an initial possibly short term driver which has expanded uncontrollably due to higher wave energy resulting in almost complete loss.
In a recent Gov. publication high resolution aerial photography was used to map seagrass coverage and distinct circles were found about 15 km off shore from Adelaide in a very consistent pattern. We concluded that these were caused from seismic testing undertaken in the 1950-60's sometime and have not regrown even though all observable conditions should allow regrowth. This is also seen in an area mined of seagrass matt in the 1930's off Port Broughton (Irving 2013: Ecography 36).
So I agree that we should protect what we have got or else it will be gone and unlikely to ever return
To keep up to date on the condition of SA marine waters check out the EPA's report cards www.epa.sa.gov.au
Full disclosure - I designed and actively manage this program
