Plastic in the Ocean: What Divers Can Do

The Scale of the Problem

An estimated 8–12 million tonnes of plastic enter the ocean annually — primarily from coastal communities in regions without adequate waste management infrastructure. The cumulative amount already in the ocean is estimated at over 150 million tonnes. It is present at every depth that has been sampled: surface waters, the water column, the deep sea floor, and within the tissues of marine animals from plankton to sperm whales.

For divers, plastic is not an abstract issue — it is encountered on virtually every dive in every ocean. Ghost nets entangled on reefs. Plastic bags caught on coral branches. Micro-pellets in the sediment. Single-use packaging on dive site floors. The encounter is personal in a way that surface-level knowledge of ocean plastic is not.

The Types of Marine Plastic

Macroplastics (>5mm): Bags, bottles, fishing gear, ropes, packaging. Directly hazardous through entanglement (sea turtles in ghost nets, marine mammals in netting) and ingestion (turtles consuming plastic bags mistaken for jellyfish).

Microplastics (1µm–5mm): Produced by the degradation of macroplastics under UV radiation and wave action, or from direct sources (microbeads from personal care products, microfibers from synthetic textiles in laundry). Ingested by fish, shellfish, and filter feeders including manta rays and whale sharks — which filter millions of litres of water daily. Studies have found microplastics in the muscle tissue of commercially sold seafood.

Ghost fishing gear: Lost or abandoned fishing nets, lines, and traps that continue to catch and kill marine life indefinitely. The most immediately visible plastic problem on dive sites globally — particularly on reefs adjacent to fishing areas. A single ghost net can entangle dozens of sea turtles, sharks, and reef fish before it is removed.

What Divers Can Do

Dive Against Debris (PADI): The most widely adopted citizen science framework for diver-based marine debris monitoring. Divers log debris type, quantity, location, and GPS coordinates, contributing to a global dataset used by researchers and policy advocates. 30+ minutes of certification training, a debris bag and slate, and internet access to upload results is all that is required.

Remove what you safely can: During any dive, safely retrievable macroplastics (bags, bottles, easily accessible nets) can be collected and surface-disposed. The limits: do not attempt to remove ghost nets in open water without proper training (entanglement risk is real); do not disturb debris that marine animals are actively using as habitat (a crab living inside a bottle is safer with the bottle than without it if removal requires disturbing a reef section).

Project AWARE Foundation: Supports dive-driven ocean clean-up events, reef monitoring training, and advocacy for single-use plastic reduction legislation. AWARE-affiliated dive centres run regular debris removal events.

Ghost Net Removal: Specialised training is available for removing large entangled fishing gear from reef systems — typically taught as part of dive leadership programs or specialist conservation courses. Experienced teams use knives designed for cutting net, float systems for controlled ascent of large debris, and surface support. This is not solo-diver work.

Systemic Action

The honest analysis: individual diver action — removing bottles from reefs, choosing reusable water bottles — has negligible impact on the 8–12 million tonnes entering the ocean annually. The structural solutions are:

• Extended producer responsibility legislation: Making plastic manufacturers financially responsible for end-of-life disposal
• Investment in waste management infrastructure in the coastal communities responsible for the largest inflows
• Bans on single-use plastics with viable alternatives in place

Diver advocacy — through organisations, at the ballot box, and in supporting businesses with genuinely reduced plastic footprints — has leverage beyond individual clean-up dives. The most effective environmental advocates are people with genuine personal stakes in the outcome. Divers qualify.