Strandloper Project

18/08/2026

The recent die off of sardines has highlighted the vulnerability of our coastal areas to exposure of development and increasing urbanization.
There is lots of wild speculation of the causes for the die off, but as happens with nature, it is not always one factor.
I am currently up the west coast, about 80km south of the Namaqua National Park, and we have recorded washed out sardines on the beach.
This report highlights some of the factors that have most likely contributed to the recent die offs.



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📰 Sardine News Special Report
Cape Town’s Sewage Crisis and the Sardine Die-Off

🚨 Sewage Discharges off Cape Town
Atlantic Seaboard Outfalls:

Green Point, Camps Bay, and Hout Bay pump 27–32 million litres of raw sewage daily into the ocean.

These outfalls are exempt from faecal bacteria monitoring, meaning contamination is largely unchecked.

False Bay Pollution:

Failing sewage plants discharge 216 million litres/day of untreated or partially treated sewage into False Bay.

Total Sewage Load:

Cape Town releases 382 million litres/day — that’s ~139 billion litres/year of untreated or partially treated sewage into rivers and oceans.

🐟 Sardine Die-Off (2026)
Observed Symptoms: Sardines were seen gasping at the surface before dying — a classic sign of low oxygen stress linked to algal blooms and eutrophication.

Geographic Spread: Mortality stretched from Saldanha Bay to Gansbaai, with sardines most heavily affected.

Causes Investigated
Harmful Algal Blooms (HABs):

A bloom of Alexandrium catenella was confirmed offshore Saldanha.

HABs produce toxins and deplete oxygen, suffocating fish.

Pilchard Herpesvirus (PHV):

Viral genetic material was detected in dead and some healthy sardines.

Scientists caution virus alone is insufficient; environmental stress likely triggered mortality.

Oceanographic Stressors:

Enhanced upwelling, unusually cold nearshore water, and low oxygen in St Helena Bay preceded the event.

🔑 Why Sardines?
Sardines are filter feeders, highly exposed to HAB toxins and oxygen depletion.

Their physiology makes them more vulnerable than larger predatory fish.

PHV may have weakened sardines, but HAB-driven hypoxia explains the gasping behaviour before death.

⚠️ Risks & Implications
Ecological: Sardines are a keystone species — die-offs ripple through seabirds, seals, dolphins, and fisheries.

Public Health: Sewage-driven HABs can contaminate shellfish with toxins (e.g., paralytic shellfish poisoning).

Governance: Continued sewage pumping into marine protected areas violates environmental rights and fuels distrust in official narratives.

✅ Conclusion
The evidence points to Cape Town’s massive sewage discharges fueling HABs and oxygen depletion, which stressed sardines and triggered the die-off. PHV was present but likely acted as a secondary factor. The “gasping for air” symptom strongly supports the HAB/low oxygen explanation.

04/08/2026

Whales and dolphins by numbers.

One Thousand
TWO
And 4

That is how the day wound down to sunset.

We had stopped in at Kleinkrans to check for whales or dolphins. As we crested the dune and looked down at the ocean, the waves were streaked with dolphins. The pod stretched along 800m of surf and extended between 600m and 800m out to sea. There were easily 1000 dolphins, surfing, breaching, relaxing, and even about 30 flushing a flock of Cape Cormorants resting on the surface.
Far out to sea a spout betrayed the presence of a Humpback Whale on its journey east.

Next stop was Swartvlei Beach to look for the Humpback Dolphins. Unlike the clear air off Kleinkrans, Swartvlei Beach was closed in with mist, with zero chance of seeing anything.

Leaving the beach, a message came through : Whale just behind the breakers at the mouth.

At the mouth there was no sign of any whale, so we headed off to Myoli Beach and scanned from the viewing platform. A chance glimpse of a black back and white patches to the east had us eagerly dashing to the Cola Beach stairs to checkout a Southern Right Whale. .

And there she was, sky hopping in all her glory, with her calf slapping it's tail, as if both were beckoning us to join them.

Even in the low light, it was obvious that this was a new collosity pattern for the season, a central sequence of 7 small dots between her blowhole and the patch at the tip of her rostrum, a small blob on her right lower jaw, and a pair of stripes flanking either side of her blowhole. This is the fourth mother calf pair that we have identified between Wilderness and Buffalo Bay for the 2026 season.

One Thousand and two down, 4 to go.

As sunset approached, mom swam steadily east, with the calf partially piggy backing. Suddenly mom banked sharp left and the calf tucked tightly on her back.
A single Indian Ocean Humpback Dolphin surfaced and the mother continued in a tight circle, again shielding the calf. A pair of Humpback Dolphins surfaced, then dived under the whales.
Still uneasy, the mother turned again, as a fourth dolphin surfaced. The whales changed course away from the dolphin, and the sky shimmered with shades of sunset.

02/08/2026

67 minutes makes a difference to the Ocean.

As part of Nelson Mandela Day, learners from Oakhill School planned a beach cleanup.
They joined Strandloper Project at Swartvlei Beach, a Beach. To start, they had a talk on the impact of ocean plastic waste, how small changes in daily choices can have a positive outcome in reducing the flow of plastic pollution into the ocean and of some of the plastic research that Strandloper Project conducts on their annual coastal research expeditions.

300m west of the iconic Lion Rock of Gericke's Point is a washout point where plastic pollution, especially plastic bottles wash out. It was a great opportunity to conduct a plastic bottle survey, with 29 bottle counted on a 30m transect, a density of 1.9 bottle/m, which is a medium to high density.

A total of 5 and half trash bags were filled with plastic pollution, removing the potential on millions of bit of microplastics entering the marine eco system.

Every bit helps protect the marine ecology. If every beachgoer collects one shopping bag of plastic pollution on an outing, it will not only reduce the threat of microplastics, but also enhance the aesthetics of the beach landscape and elevate everyone's beach experience.

Well done to the leaners of Oakhill School.

01/08/2026

Reef, fanworms, and dorids beneath the waves.

To celebrate Marine Protected Areas Day, Strandloper Project volunteers conducted a Bio Blitz and reef clean up at Gericke's Point.

Diving in, the first thing that we heard was the high pitched squeaks and clicks of dolphins. There was a large pod of over 300 Bottlenose Dolphins and 8 Humpback Dolphins in the bay, and it was pleasure simply to remain suspended beneath the surface and listen to them.

Though technically, Gericke's Point is not an MPA, it has incredible marine biodiversity that deserves protection and conservation.

By documenting the intertidal and reef species, we contribute to the database of species that occur there, and note recruitment of new species due to rising sea temperatures.

Images are still being uploaded to iNaturalist, but we estimate that we managed to photograph over 75 species.

Sadly, any activity in the ocean nowadays results in encounters with snagged recreational fishing terminal tackle and ocean plastic pollution.

We collected 72 sinkers, 22 of them all clustered together in one crevice in the high cast zone.

Our intention was not to do a cleanup today, and as such we did not have our floating bucket to collect the snagged terminal tackle and will have to conduct a dedicated cleanup shortly.

Thank you to everyone that managed to today.

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29/07/2026

Whales, Dolphins and Oystercatchers on a trail of plastic.

Plans are underway for the 8th Strandloper Project coastal research expedition. In October our team will hike from Wilderness to Nature's Valley, approximately 145km along a predominantly rocky shoreline.

Strandloper Project began their annual coastal research expedition series in 2019 with the objective of mapping ocean plastic waste, washed-up fishing gear and indicator marine fauna species.

In the first series for five expeditions we hiked 980km between Hermanus and Cape Recife. For the second series, we are repeating the same strip of coastline, though have extended it from Pringle Bay to Cape Recife.

We use a combination of survey methods that categorize plastic types and quantify their densities. From the onset of the first series, we seperates plastic particles into colour spectrum categories.
Using ratios of colour spectrums, along with indicator items, we formulated a rough forensics methodology to determine the source of plastic plastic pollution flowing into the ocean, as densities of colours and indicator items changed the further that they had drifted in the ocean.
Recently, if was wonderful to see that various ocean plastic are now beginning to categorize microplastics into colours as studies fave found different densities of coliurs in tissue and blood of marine species, suggesting that certain colours are targeted by fish, sharks, turtles and birds.
On our initial expedition, the focus was on fishing debris and the risk of ghost fishing, entanglements and physical damage to reef cover, and we still record both recreational and commercial fishing debris on the route.
Another valuable database that we have built up is that of marine fauna as we hike on sections of shoreline that few researchers study.
African Black Oystercatchers are one of our primary avian species and we have recorded over 2000 birds between Pringle Bay and Cape Recife. This has crucial in identifying factors, such as intertidal geology and aspect, that influence the density and distribution of this species. We have observed also variations in territories, nesting and foraging behaviour along different sections of the shoreline.
So far, in the second series, we have recorded changes in regional population densities, with some populations increasing by more than 5% within a 3 year period.
This year, we will be focused on Oystercatchers again as the highest density of this species occurs between Wilderness an Buffalo Bay and it will be interesting to see if there is stability or change in the population.
We will also be recording Southern Right Whales, Indian Ocean Humpback Dolphins and Humpback Whales.
All our observations are recorded in our expedition program in Cybertracker, providing an accurate geo-referenced database for spatial analysis.
Each of our expeditions would not be possible without support and sponsorship of local businesses and residents along our hikes.
We are thankful to our anchor sponsors and angel donors for their support in the past and their pledge for this years expedition.
Accommodation and heat an meals are vital part of the success of each expedition, and this year is no different. We have already been pledge accommodation for 5 nights and are looking for 4 more nights on the route.
Anyone that is able to support our 2026 expedition can reach out via Whatsapp on 082 213 5931 or email on [email protected].

An so, the adventure begins as we collect more valuable data to assist with the conservation of our marine heritage along the Southern tip of Africa.

For more information visit our website.

28/07/2026

The 1st August is MPA Day, an event that started in South Africa and is now recognised internationally.
In recognition of this important marine conservation day, Strandloper Project will be conducting a combination of a Bio Blitz and a beach cleanup.

We will Bio Blitz on the walk to Gericke's Point and then collect trash on the way back.

A Bio Blitz is an event that aims to document as many species in an area, relying on enthusiasts to photograph all species seen and then to load them to iNaturalist. Species don't have to be identified when being photographed. When the images are loaded to iNaturalist identification is suggested and then confirmed by online experts. It is best to enable geo tagging for the photos.

It is also a great way to build up a baseline of biodiversity at a location.

For the Bio Blitz, you will need the following apps on your smart phone
1. iNaturalist
2. Seek for iNaturalist.

Seek allows instant identification of most of what you see.

If conditions are suitable, we will try to snorkel and get some underwater images to add to the Bio Blitz. If anyone else has an under water camera and wants to join, that would be great.

There will be bags available for collecting trash.

Logistics :
* Date : Sat 1st August
* Time : 10h00
* Meet : Swartvlei Beach parking area
* Gear needed - camera, smart phone, snorkel gear if you want to get underwater photos.

For more details contact Mark via Whatsapp on 082 213 5931.

23/07/2026

World Whale and Dolphin Day

As we celebrate World Whale and Dolphin Day, it is exciting to share some of our seasearch records.

Probably the most exciting is that yesterday we managed to identify a third mother calf pair of Southern Right Whales between Knysna and Wilderness.
We recordsed the first pair in early June, and using the mothers collosity pattern, recorded them at three different locations.
Then in early July, we identified a second pair near the Swartvlei Estuary mouth, the calf being much smaller than the first one, and a light grey colour.
Then yesterday, a third pair was spotted offshore from Wilderness. In addition to a distinctive collosity pattern, the mother also had a central white stripe on the upper side of her tail.

The Humpback Whales have also be around, though they are normally between 3.5km and 6km offshore. Still visible with binoculars, but not close enough to get any detail.

On Sunday, we did have a fortunate sighting of a mating pursuit, with 3 males chasing a female, about 1200m offshore from Buffalo Bay. They were cruising fast, the male vigorously ramming each other, in a three way challenge for mating rights. What was remarkable to see was the agility of the males as they turned to avoid being rammed and to cutoff a challenger from approaching the female.
Testimony to the effort of these challenges was the pause to get in four to five breaths before diving into the chase again.

The Indo-Pacific Bottlenose Dolphin pod has been regularly cruising between Buffalo Bay and Wilderness, with small breeding pods of 30 to 50 dolphins breaking off to rest after pack hunting. When hunting, the pod can be as many as 1000 dolphins, often with 500 faster dolphins leading the rest of the pod.

A personal favorite are the Indian Ocean Humpback Dolphins. The Swartvlei Beach site has been interesting to monitor over the past year, with an average of 8 dolphins and a maximum of 18.
Mating activity in June was interesting with one female successively mating with three males.
The energetic cost of such vigorous mating that lasted for over an hour, was evident when she was observed lying motionless on her back for close to two minutes. Two males nudged her, before she righted and continued.
They also seem to commute between Swartvlei Bay and Platbank in the Goukamma MPA to hunt.
Currently there are two calves present.
For two weeks, a lone dolphin was sighted in the bay.

Yesyerday, at sunset a mother calf pair of Humpback Whales performed a series of breaches about 3km offshore from Swartvlei Beach. It was overcast, the wind forming white water on the ocean. Through the clouds, a shaft of sunlight focused on the pair, their white underside and pectoral fins glowing while they were airborne. To far to photograph, but beautiful enough to close the day.

Here's to the remarkable marine fauna that we have the privilege to observe on a regular basis.

23/07/2026

Sub Antarctic Fur Seal Rescue

On Tueaday the Plett Stranding Network received an alert about a small seal on Myoli Beach.
The message was shared with the Sedgefield Stranding Network, and so began a smooth process of capture and transport of the seal to Bay World in PE for health maintenance and rehab prior to a future release.

Phase 1. Colleen from SAMS arrived with a dog crate and was assisted by Helia from the Island Conservancy and Strandloper Project , who are licensed handlers of stranded marine mammals, to secure the seal in the cage.

Sub Antarctic Fur Seals are a vagrant species from the Sub Antarctic region. In 2020, when Strandloper Project rescued their first Sub Antarctic Fur Seal (subbie), it was the 11th recorded one of this species documented in South Africa. During that winter approximately 9 were rescued, an indication of a change of conditions and food supply in the Southern Oceans.

Phase 2. Once the subbie was secured, it was driven by Strandloper Project to Plett and handed to Chanel from Cape Nature to stabalise it, and to await for Phase 3, the collection by Bay World for the final trip to Bay World for rehab.

The subbie was very small, thin and had small barnacles attached to it's rump, indicating that it had been floating for at least 4 weeks before washing up.

The first 24 hours after rescue are critical, and it was with a sigh of relief that we recived the news that the subbie had survived the night and had had a hearty meal of vitamin enriched fish gruel for breakfast. In addition to food, it will be inoculated against rabies to prevent it being a vector for the virus when it heads back to its colony in the Southern Oceans.

Phase 4. The process now is to feed it till it reaches a target weight appropriate to its length before it is taken about 40km offshore and dropped into the Agulhas current, where hopefully it heads south and returns to its home range, most likely at the Prince Edward Islands, approximately 4500km south east of our coastline.

From previous releases of GPS tagged subbies, their daily speed once in the Agulhas current is about 200km per day.

As the subbie was rescued in front of PiliPili, it has been named PiliPili, and if it gains weight, it should reach its target release weight in about 8 weeks time.

Gear for the Sedgefield Stranding Network. Two things that were highlighted from this rescue were firstly, the incredible Network of people and organizations that coordinate a time sensitive rescue for the well-being of a marine animal.
Secondly, that the Sedgefield Stranding Network require dedicated response equipment for future events. To save time, it would be ideal to have rudimentary PPE, catch poles, crates/ cages, toweling and strapping stored in one location. SAMS have volunteered their premises as a central storage. We now need to acquire the equipment.
Bay World will be providing a list of essentials gear for a rescue, and once we recieve it, we will request donations to purchase it.

Bay World is hoping to raise funds to get a GPS tracker for PiliPili so that we can monitor his return journey.

For now, we wait for the moment that PiliPili is released on his return to the Southern Oceans.

20/07/2026

Ghost fishing webinar this morning.
Date 20th July
Time :12h00
Link :

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18/07/2026

Ghost fishing and avian entanglements on

As part of the NRF | SAASTA National Science Month program, Mark Dixon will be presenting findings from the Strandloper Project's citizen science monitoring program on ghost fishing and avian entanglements caused by lost and discarded terminal tackle from shore based recreational fishing activities. The presentation will cover variations in causes of snagging, reef damage and reef regeneration, as vulnerable fish types.

The presentation will be online through the link below.

Date : 20th July

Time : 12h00 to 13h00