Reef Clean Up : Knysna Heads

Jessica from the Knysna Basin Project gave the dive briefing. There were two groups, free divers on the shallower reef and SCUBA divers on the deeper reef.

In conjunction with Knysna Basin Project, Strandloper Project volunteers conducted a clean up dive to remove lost and snagged recreational fishing gear on the eastern side of the channel flanking the Paquita Wreck.

The planned clean up dive along the reef on the eastern side of the channel, extended from a cove south of the wreck to the northern edge of the wreck.

There were 20 volunteers divers from Mosselbay, Sedgefield, Knysna and Harkerville.

Illegal Fishing

Despite clear signage demarcating the area as a no fishing zone, sadly it is continuously fished by all LSM groups, both from the shoreline and boat.

During our briefing there were locals fishing, right next to the signage alerting the public that the area is a no fishing zone.

The combination of the strong currents and the gradually shelving channel provides an ideal feeding ground for a variety of estuarine and oceanic fish species which aggregate over the wreck and along the reef in the adjacent coves.

As the tides change, particularly at the start of the outgoing tide, the fish aggregate, ready to feed on the detritus and nutrients flushed out of the estuary, making this section of the shoreline a popular fishing location.

Sublime Dive Conditions

Notorious for sketchy ocean conditions, planning a dive in the the channel at the Knysna Heads has to take into account tide, viz, wind and temperature to make it worthwhile. With 8m viz, 17Deg C and no swell, we could have not asked for better conditions for our clean up dive.

Shore entry through the arch

Free divers entered through the arch south of the East Head Cafe and focused on the immediate cove, while SCUBA divers entered from the NSRI slipway and headed to the channel north of the wreck.

Acceptable visibility and mild sea temperatures made for ideal dive conditions.

An example of the typical ‘birds nest’ of entangled monofilament found on the reef in the Knysna Heads.

Removing the monofilament from the reef and red bait requires delicate manipulation.

The majority of the snagged fishing tackle removed was entanglements of multiple lines which had snagged on each other.

It was interesting to see that lead sinkers had accumulated in pockets and were surrounded by a bare patch of reef, a possible impact of lead poisoning.

Monster Haul of Monofilament

Divers with the haul of monofilament recovered from the dive. Most of the monofilament was collected by the SCUBA divers in the deeper water

In over four years of reef clean up dives at Gericke’s Point and in the Knysna Heads, this is the largest haul of monofilament.

What is interesting to note is that almost 50% of the snagging occurred as a result of tackle snagging on existing snagged tackle.

The rest of the snagging, common to this section of reef, is caused when a hook embeds in to a red bait and the fishermen breaks the line off. While this reduces the incidences of ghost fishing, it does result in high amounts of monofilament being lost.

Approximately 110 lead sinkers and 40 spark plugs were recovered. In addition, there were some innovative sinker substitutes.

The post dive sorting of the recovered fishing tackle is tedious, but it offers some insight into what categories of fishermen the tackle is originating from.

An interesting find on the shallow reef were a number of stones wrapped in plastic, an innovation by low income fishermen who can’t afford lead sinkers. While this reduces the amount of lead lost on the reef, sadly it contributes to the plastic pollution in the Estuary.

Lures provide insight into the socio economic demographics of fishermen using the site.

Appreciated Efforts

An oceanic ‘High Five’ to all the volunteers for their efforts t clean the reef.

I would like to extend a huge thank to everybody for helping with the cleanup efforts on this clean up dive. Sadly, we have plenty more to do, one dive at a time.

Strandloper Project

For more information on the impact that snagged recreational fishing tackle has on reef biodiversity and productivity, visit our Strandloper Project website.