My guess (which is a total stab in the dark) is that the skilled anglers were down there either at high tide (mid afternoon) or very early in the morning, which would have been a receding tide.
The seagrass beds on the RHS of the jetty were only about 2m deep when I was there.
Will try again over the coming week, when the high tide coincides with twilight.
Hopefully will have some luck.
Edited by glen, 12 January 2011 - 04:37 PM.