Strandloper Project’s team prepare for their 2024 coastal research expedition

What started out as a desire to learn more of the impact of recreational fishing along the southern Cape coastline, has, for the Strandloper Project, grown into an extensive series of coastal expeditions surveying the density and distribution of ocean plastic waste.

Since 2019, in their first series of expeditions, volunteers of the Strandloper Project have hiked 960km along the shoreline between Hermanus and Cape Recife. Depending on if the shoreline is rocky or sandy beaches, the team of volunteer’s hike between 15km and 30km per day, surveying for plastic pollution, washed up fishing gear, marine fauna, and African Black Oystercatchers.

This year, between the 5th and 18th October, a team of six hikers, supported by their backup driver, will hike from Pringle Bay to Struisbaai, a distance of approximately 220km.

Using a variety of survey methods, all plastic and fishing debris is recorded using CyberTracker which captures a geo-referenced dataset for detailed analysis after the expedition. The primary survey method is their Trashy20 survey which is conducted every 5km. Each survey comprises three 10m x 2m transects at the highwater mark, within which every piece of plastic pollution and fishing gear is collected to be categorized and counted. Drawing on surveys from their 2019 expedition, the Strandloper Project has identified the top 20 types of plastic recorded, hence the name Trashy20, which provide valuable insight into the origins of plastic pollution in the ocean.

One of the 20 categories is microplastic, pieces of plastic that are between 1mm and 10mm. For the survey, microplastics are divided into 5 subcategories, namely nurdles, white spectrum, blue spectrum, red spectrum and black items, each of which appears to have different drift distances.

Documenting the density and distribution of nurdles is of particular interest, as it can provide insight into sources of their loss into the ocean. While the 2017 and 2020 nurdle spills in Durban and the Eastern Cape respectively are well documented, less well known is the almost constant washup of these plastic pellets along the South African shoreline. Surveys in 2018 and conducted during their 2019 expedition, prior to the 2020 nurdle spill, indicate that there are significant densities of nurdles washing up that are not related to catastrophic spill events, with possible sources from industrial sites flowing into the ocean through rivers and municipal infrastructure.

To compliment the Trashy20 surveys, mini transects of plastic lids, microplastics, earbud shafts and plastic bottles are conducted.

Incidental sightings of marine mammal and bird species are recorded, and on previous expeditions have provided valuable information to Cape Nature, SANParks and state vets as they were able to provide current information on a daily basis during the Cape Cormorant avian flu epidemic in 2021, as well as the elevated Cape Fur Seal mortalities of the same year. This year, with the current rabies outbreak in Cape Fur Seals, Strandloper Project will again provide daily updates of seals exhibiting rabid behavior.

On the environmental side, data collected from expeditions between 2020 and 2023 have provided valuable insight into various factors that influence the density and distribution of African Black Oystercatchers, and Strandloper Project are eager to extend their dataset to Pringle Bay, as well as compare data from their second series of expeditions to determine what the impact of sea level rising has on this species. Their initial research in the Garden Route indicates that intertidal shelves have been inundated by sand during mid-summer, the peak of the breeding season of oystercatchers, significantly reducing recruitment in affected areas through lower food availability.

A focus of this year’s expedition will be to document snagged and discarded monofilament used by recreational fishermen. In the first series of expeditions, the worst affected shoreline of washed out monofilament was during the 2021 expedition between Arniston and Hermanus. Associated with the high incidence of monofilament was the number of fish, primarily elasmobranchs, killed as a result of ghost fishing, the lethal process of being unable to escape from snagged terminal tackle, particularly in kelp forests. Each expedition has two or three items that have higher densities than other regions, and around the southern tip of Africa, it is undisputably monofilament.

As the world prepares for the fifth International Intergovernmental Negotiating Committee in South Korea to develop an internationally binding instrument relating to plastic pollution, expeditions such as this contribute valuable information by providing precise information categorizing the density and distribution of ocean plastic waste and its geological reference to regional human settlements.

You can follow the progress of the Strandloper Project on their 2024 coastal research expedition on their social media platforms. For more information you can visit their website at www.strandloperproject.org or email expedition leader Mark Dixon on ghostfishing@strandloperproject.org

Note : Expedition crew

  • Mark Dixon
  • Chris Leggatt
  • Jonothan Britton
  • Mandy Pelser
  • Liz Bazin
  • Ariadne Van Zanbergen
  • Nick Leggatt – back up driver
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