Marine litter in UK waters
More than half of minke whales that have been subject to post-mortem examination in Scotland displayed evidence of entanglement around their head or mouth and other parts of the body, where they had become entangled in ropes or static fishing lines. As in many other parts of the world, the entanglement of whales is a considerable threat, especially in coastal waters.
For whales and dolphins, becoming tangled in discarded or active fishing gear is a major welfare issue. A minke whale was found dead off the coast of Shetland, Scotland in June 2007 after becoming entangled in plastic strapping usually used for packaging. The whale was initially sighted at sea; the animal was alive but clearly emaciated and had a large wound behind its head caused by the strapping. The discarded packaging had become wrapped around the head of the animal and is likely to have prevented the whale feeding properly for a considerable time.
Such entanglement is a real welfare concern that can often impair the animals’ ability to swim, breathe and find food. Entanglement may also cause injury and wounds as the animal tries to disentangle itself from the litter, which can subsequently lead to infection. A recent US scientists recently wrote "Chronic cases can involve impaired foraging, increased drag, infection, hemorrhage, and severe tissue damage. The individual suffering of these cases appears to be extreme".
Many whales and dolphins have been found to ingest marine litter, either accidentally but most likely because they look similar to prey species usually taken by the animals. Consumption of marine litter can cause physical damage of the digestive tract. Once ingested, the litter can block the digestive tract, prevent digestion and lead to starvation. Litter can also accumulate in the stomach of the animal and produce a false sensation of being full, reducing the animal’s instinct to feed or the ability of the digestive tract to absorb nutrients. This is also likely to result in starvation.
In 2003, a Cuvier’s beaked whale washed up on the coast of Mull, Scotland. This species is usually found in deep, offshore waters and feeds primarily on squid. Analysis of the stomach and intestinal contents of the dead animal revealed a proportion of shredded plastic bags. It is highly likely that the whale mistook this litter for squid, and that ingestion of the plastic contributed to the death of the whale (www.whaledolphintrust.co.uk). In 2002, a minke whale washed up on the northern French coast and, shockingly, had ingested almost 800g of plastic bags.
We all have a role to play in reversing this trend. A recent Marine Conservation Society report shows an increase of 126% in the amount of plastic debris recorded in UK beach cleans since the ongoing survey began in 1994.
In 2007, a Memorandum of Understanding was formed between the United Nations Environment Programme (UNEP) and OSPAR to look at ways of producing worldwide protocols for monitoring marine litter. We hope this terrible trend starts to reverse now with increased awareness and most recently, the introduction of the Marine Strategy Framework Directive, which also includes measures specifically to deal with marine litter.
However, the issue of marine litter remains a serious one that is potentially life threatening to whales and dolphins in UK waters. WDC conducts regular beach cleans at our Scottish Dolphin Centre, including as part of the Marine Conservation Society's beachwatch.
Please dispose of your rubbish responsibly to prevent it ending up in the sea and harming wildlife.