The tide line at Noetzie Beach is a long and winding treasure chest. Beautiful bleached driftwood, a few special shells and amazing creatures.
Sadly, litter from the polluters out at sea and Knysna’s storm water drains also line the shore. We started cleaning the tide-line a few years ago and this has also trained our eyes to find and locate all objects that are out of place or beautiful. We once found an injured Boomslang. It was almost in the sea water and still moving, we guessed that a bird could have dropped it onto the beach. We carefully placed it back in the forest, using a pair of braai tongs.
Other interesting finds were scores of dead pipefish. See Fran Kirsten’s article , in full published in the Knysna Plett Herald
Scores of Pipefish Dead
01:00 (GMT+2), Thu, 08 December 2011
These pipefish (Syngnathus Capensis) are related to the seahorse and occur in all the local estuaries and are preyed on by various fish species that enter the estuaries. The resident offered a hypothesis, “Perhaps the dredging at Ashmead or somewhere in the lagoon, or the recent pollution from sewage, is killing them, and the westerly winds then wash them onto Noetzie Beach.”
Another report of dead pipefish was received from a diver who had recently dived at the Knysna Heads. “It is the sewage” he said, “I went for a scuba dive on Friday, December 2 and I saw lots [dead pipefish] at The Heads.”
Professor Brian Allanson, Knysna resident and aquatic and estuarine ecologist said, “To have such a high mortality, points to a major environmental disturbance.”
He explained that pipefish prefer to live within the estuary’s eelgrass beds. “If these beds are exposed to pollution, then the pipefish will be exposed to many dangers – predation or rapid lowering of dissolved oxygen linked to sewage pollution and associated toxic compounds such as dissolved ammonia.”
Allanson added that he was “tempted to point a finger at the recent extreme sewage pollution of the estuary. This would have reduced dissolved oxygen and introduced ammonia.”
In closing he said that the fact that the dead pipefish have been washing up for over a month, suggests that a major pollution event was the most likely cause.
André Riley, area manager for Knysna Garden Route National Park, said that although it is often difficult to pin-point the cause of high mortalities in the environment, he agreed with Allanson that “it [the dead pipefish] is linked to an environmental event. However these events are in some cases natural and/ or as a result of disturbances caused by humans.”