MARINE DEBRIS and MICROPLASTICS - BOTH HUGE and INCREASING ISSUES

- July 01, 2024

In previous blog posts you may recall me talking about marine debris and ghost nets being an issue around Croker Island. From the air, beaches like the one below look clean however a closer look often reveals a very different situation.

In early June we had two officers from the Commonwealth Government's Department of Agriculture, Forestry and Fisheries (DAFF) here for a few days. During this time they trained us to conduct a Marine Debris Transect Survey. The results were quite alarming!! Read on to find out more.

The survey involves marking a section of beach 100 metres by 20 metres. We choose a section of east facing beach near Cape Croker (northern part of Croker Island). Then we had to pick up all the debris within this marked area, weight it, sort it into 50 categories and then count these categories. The data was then entered into the Biosecurity Topwatch app on our iPads to be sent off to DAFF when we returned to the office and WiFi connection. I won't go through all categories but below are just four.

Plastic bottle caps = 409
Pieces of net/rope = 160
Thongs and shoes = 77
Pieces of plastic = 373

The 409 plastic bottle caps particularly shocked me - 409 off this small section of beach! I thought, how many of these things are there floating around in our oceans and lying in the coastal areas of our planet?

Below we are collecting the debris from the survey area.

Back at the ranger base we sort the debris into categories and count.

Over the last year we have collected around 2400 kgs of marine debris off the beaches of Croker Island.

Plastics make up most of this debris. The sun breaks down plastics into smaller and smaller pieces referred to as 'microplastics'. This is an emerging and not well understood issue. For those interested, check out the link below.

https://www.marineconservation.org.au/microplastics/

Recently I attended an Indigenous Rangers Biosecurity Conference in Darwin. There were rangers there from right across northern Australia. I sat at a table with ranger coordinators from Normanton, Mornington Island and Burketown. They all have significant marine debris (including ghost nets) problems. The photo below shows where the Biosecurity Indigenous ranger groups are located. We are in the middle up the top of the map - just under the 'g' in Ranger.

The Google Earth screenshot below shows a large ghost at McClure Island just off the beach. We retrieved this net off a reef and anchored it here in late 2022. We have been waiting over 18 months for the various government departments to decide how to dispose of this large net. There has been a lot of 'buck passing'!