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Killer waters – why the UK’s polluted sea led to the death of a whale

  • Written by  Tess McKain
  • Published in Oceans
Tests run on ‘Lulu’ the killer whale found her blubber to have 100 times the amount of PCB contamination required to cause damage to the species Tests run on ‘Lulu’ the killer whale found her blubber to have 100 times the amount of PCB contamination required to cause damage to the species John Bowler/RSPB Scotland
24 May
2017
Analysis into a killer whale found dead off the shores of western Scotland have revealed the shocking levels of chemical pollutants in the UK’s waters

On a cold November in 2016, a female killer whale washed up on the shores of the Isle of Tiree in western Scotland, having been caught up in fishing lines used to haul lobster cages up from the seabed. Known as Lulu, the deceased animal was a member of the UK’s last resident killer whale pod, which hunts amid the waters in and around the UK all year round. Lulu was estimated to be around 20-years-old, and was part of a pod that had been monitored for 23 years.

Lulu’s appearance on the beach was unexpected, and scientists seemed to be at a loss to explain how an otherwise healthy killer whale was unable to orient herself out of danger once she had become tangled in the fishing lines. Although the circumstances surrounding Lulu’s death were known, why it had occurred remained a mystery.

Lulu (Image: John Bowler/RSPB Scotland)Lulu’s corpse was washed up last November after having been caught in fishing lines (Image: John Bowler/RSPB Scotland)

Six months later, following a post mortem conducted by Dr Andrew Brownlow, head of the Scottish Marine Animal Stranding Scheme and veterinary pathologist at Scotland’s Rural College, results from an analysis of Lulu’s blubber have revealed that she had the highest levels ever recorded of toxic PCBs in her system, which could have affected her ability to free herself once she became caught up. According to a WWF report on Lulu’s death, the whale was found with 950mg of PCB in her blubber, which is over 100 times upper limit of 9mg that is known to cause damage to marine species. The average contamination level for killer whales in the Atlantic Ocean is 150mg.

The analysis of the blubber also goes some way towards explaining why no calves have ever been been seen with the pod – excessive exposure to PCBs is known to cause infertility in animals, leading many to fear that the pod are now likely to become extinct.

Whale pods are traditionally migratory, but Lulu’s group kept to the shores of the UK (Image: Monika Wieland Shields)One effect PCBs have on the species is to cause a loss of fertility (Image: Monika Wieland Shields)

PCBs, or polychlorinated biphenyls, are man-made chemicals known to cause adverse health effects in both humans and wildlife. PCBs were developed in the 1930s, when they were widely used as dielectric and coolant fluids in electrical goods. It wasn’t until the 1970s that health implications of widespread PCB use were realised, with known side effects to continued exposure resulting in possible hepatic and respiratory damage in humans, and a host of dangerous side effects in animals, including infertility and death.

Although most countries have banned the manufacture of PCBs, issues surrounding their disposal have continued to linger. PCBs take a very long time to deteriorate, and as demonstrated by the toxic levels discovered in Lulu’s blubber, some have found their way into the world’s oceans. Killer whales are apex predators, meaning that no other predator feeds on them. This makes them highly susceptible to PCB contamination, as levels of the contaminant build up in consistently larger levels higher up in the food chain.

The death of Lulu represents a small but important slice of the wider legacy of ocean pollution that is being revealed as time passes. Whilst most whale pods are migratory, Lulu’s group of eight killer whales were the only known pod to reside exclusively in waters off the west coast of the UK.

Whale pods are traditionally migratory, but Lulu’s group kept to the shores of the UK (Image: Tony Mills)Whale pods are traditionally migratory, but Lulu’s group kept to the shores of the UK (Image: Tony Mills)

PCBs are an odourless, colourless pollutant, and Lulu’s death was a visible consequence of an otherwise invisible pollutant in the UK’s waters. In recent years, ocean pollution has moved into mainstream discourse in the UK media, but PCBs are just one of a slew of pollutants affecting marine life in the UK.

The UK government’s website notes that oil spills, plastic pollution, and overfishing are all factors that contribute to pollution and wildlife loss in and around UK waters. Over the last year the Scottish government has set up over 30 new Marine Protected Areas in order to try to reverse the increasing lack of biodiversity in Scottish waters. The purpose of marine protected areas is to ‘adopt an ecosystem approach to manage the growing pressures of diverse human activities in an environmentally sustainable way’. Part of this process is to ensure that issues such as overfishing and plastic pollution are addressed.

Currently, 60 per cent of Scottish fishing industries are operating at capacity, with a further 30 per cent consistently overfishing. The UK is governed by the EU’s common fisheries policy, which underwent major reform in 2013 in an attempt to make fishing more sustainable in the long-term. Although this is positive news, there are concerns about how environmental policy will be shaped by the UK’s exit from the EU, with some charities urging the government not to abandon its pledge for ocean sustainability post-Brexit.

Sixty per cent of Scotland’s fishing industry is operating at capacity (Image: Marten Lagendijk)Sixty per cent of Scotland’s fishing industry is operating at capacity (Image: Marten Lagendijk)

Recent government initiatives in the UK and the EU have also focused on trying curb the use of some single-use, non biodegradable plastics, such as plastic bags and cutlery. Estimates for how much plastic ends up in the sea per year very, but the World Economic Forum estimates that around eight million metric tons of plastic ends up in the world's oceans annually. The implications for this on wildlife is huge, with many fish and bird mistaking plastic for food. Non biodegradable PCBs and plastics have even been found 10km deep in the Mariana trench.

Erik van Sebille, a research fellow and lecturer at Imperial College, London, notes that ‘until we know where the millions of tons of plastics reside in the ocean, we can’t fully understand the full suite of its impacts on the marine ecosystem.’ He suggests we act now to ‘turn off the tap’ to prevent waste from entering the oceans in the first place.

Waste plastics have been found in the Mariana trench at depths of 10km (Image: Rich Carey)Waste plastics have been found in the Mariana trench at depths of 10km (Image: Rich Carey)

The UK government now enforces strict rules on the disposal of PCBs, but unfortunately it is estimated that up to ten per cent of all PCBs ever produced are now already in the world’s oceans. The death of Lulu, and the apparent infertility of her pod is a stark reminder of the ecosystems at stake through the inadequate disposal of non-biodegradable materials. In the case of PCB pollution, knowledge of the dangers of the chemical came after its mass manufacture, which then created the problem of its safe disposal. On the other hand, plastics continue to be manufactured at an ever increasing rate, without due precautions as to how to dispose of them after use – despite knowledge of the damage they cause to oceanic ecosystems.

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