Whale Pollution Victims: Counting The Casualties Of Human Impact

Marine pollution is a serious threat to whales, with human activity posing a direct danger to these giant mammals. Oil spills, industrial pollutants, litter, sewage, noise pollution, and plastic waste are all factors that contribute to the issue. One of the most pressing concerns is the presence of PolyChlorinated Biphenyls (PCBs) in the water, which build up in the food chain and have detrimental effects on the fertility and longevity of whales. Whale health is a critical indicator of ocean health, and with more than 11 million metric tons of plastic entering the ocean each year, it is clear that human activity is having a devastating impact on these majestic creatures.

Plastic ingestion

Marine plastic pollution is a pressing issue that affects all kinds of marine life, including whales. Plastic ingestion is one of the two primary ways in which plastic pollution harms marine life, the other being entanglement.

Whales are ingesting plastic in larger quantities than previously thought, and nearly all of it comes from their prey rather than from the seawater they gulp when feeding. A recent study published in Nature Communications focused on blue, fin, and humpback whales and their consumption of microplastics. The study found that whales predominantly feed 50 to 250 meters below the surface, which coincides with the highest concentrations of microplastic in the open ocean.

The planet's biggest creature, the blue whale, ingests the most plastic, with an estimated consumption of 10 million pieces per day as it feeds almost exclusively on krill. Humpback whales that subsist primarily on fish such as herring and anchovies ingest an estimated 200,000 pieces of microplastic per day, while those consuming mostly krill ingest at least 1 million pieces. Fin whales, which feed on both krill and fish, ingest an estimated 3 million to 10 million microplastic pieces per day. Consumption rates are likely even higher for whales foraging in more polluted regions, such as the Mediterranean Sea.

Whales are not the only species affected by plastic ingestion. Dolphins, sea turtles, seabirds, and fish around the globe are also impacted. Globally, more than 240 wildlife species, including whales, are known to have ingested plastic, which can result in internal injuries and death.

Plastic bags and packaging are responsible for the largest proportion of deaths from debris, primarily due to gastric obstructions. Flexible plastics can block the breathing passages and stomachs of whales, leading to excruciating and sometimes fatal consequences. In one case, a stranded sperm whale in Indonesia was found to have ingested over 13 pounds of plastic, including bags and flip-flops. Even deep-diving species like True's beaked whales have been found with plastic in their stomachs after stranding on beaches in Ireland.

Microplastics, plastic pieces smaller than 5mm, are of particular concern for baleen whales as these giant creatures can end up ingesting large amounts of microplastics along with their prey while filter feeding. Additionally, microplastics can act as "pollution sponges," absorbing and concentrating toxic chemicals from the surrounding seawater. These toxic chemicals can then be released into the bodies of whales and other marine organisms that ingest them, potentially causing harm to their reproductive and overall health.

Addressing Plastic Pollution

Plastic pollution is a global issue that requires a coordinated effort to address. Organizations like the World Wildlife Fund (WWF) are advocating for better waste management systems, bans on single-use plastics, and legally binding targets to eliminate plastic waste by 2030. Individuals can also play a role by reducing their plastic consumption, especially single-use plastics, and supporting initiatives to clean up and protect our oceans and marine life.

Entanglement in fishing gear

The consequences of entanglement can depend on the location and severity of the entanglement on the whale's body. For example, a study found that the average survival time for North Atlantic right whales that could not free themselves was about five months, with some living for years and others dying immediately.

Responding to entangled whales can be dangerous, and it requires trained experts to handle the situation effectively. The process involves understanding whale behaviour, biology, and health, as well as handling ropes and coordinating response teams. The tools used for disentanglement, such as specialised knives, lines, and large buoys, also pose risks to responders, including the possibility of being pulled overboard.

In recent years, there has been an increase in reported whale entanglements, with a total of 46 confirmed cases off the coasts of California, Oregon, and Washington in 2018. The sources of the entangling gear are often unknown, and any lines, cables, or chains in the ocean can pose a risk.

To address this issue, organisations like the National Marine Fisheries Service (NMFS) in the US have implemented regulations as part of an Atlantic Large Whale Take Reduction Plan. These regulations aim to reduce entanglement-related deaths, especially those caused by lobster traps and gillnets. However, the effectiveness of these regulations is uncertain, as right whale deaths attributed to fishing gear have increased since rulemaking efforts began.

The problem of whale entanglement is not limited to a specific region, and it requires global efforts to address it effectively. The International Whaling Commission (IWC) launched a Global Whale Entanglement Response Network in 2011 to build safe and effective response capabilities worldwide. This programme includes training for scientists, conservationists, whale watching operators, fishers, government representatives, and coast guard services.

Oil spills

The 1989 Exxon Valdez oil spill in Alaska's Prince William Sound is a notable example of the devastating effects of oil spills on whales. The spill released 11 million gallons of oil into the ocean, and two groups of killer whales swimming through the sound at the time experienced an unprecedented number of deaths in the following year and a half. One pod of resident killer whales lost 33% of its population, while a pod of transients lost 41%. One pod of resident killer whales has still not recovered, with their numbers continuing to decline steadily and significantly since the spill.

There are various ways in which oil spills can affect whales. One of the main ways is through ingestion of oil, either by eating prey that has been contaminated or by swallowing oil while swimming through it. Inhaling fumes from the oil or toxic chemicals evaporating from its surface can also be harmful, potentially causing pneumonia and other complications. Oil can also irritate the skin of whales, causing ulceration.

In addition to the direct impact on whales, oil spills can also kill off smaller animals, such as krill, that are a food source for whales. This can reduce the availability of food for whales and further contribute to their decline.

To mitigate the impact of oil spills on whales, "hazing" methods are sometimes used to deter whales from entering the area of the spill. These methods include acoustic deterrent devices, pre-recorded whale calls, Oikomi pipes, boat traffic, helicopters, and fire hoses. However, these techniques are not always effective, and capture and rehabilitation of whales affected by oil spills is often not feasible.

Noise pollution

The primary sources of ocean noise pollution are ship traffic, oil and gas exploration, scientific research, and military sonar and communications equipment. These activities generate intense underwater noises that can cause acoustic trauma and even death among whales and other marine life. The constant drone of ship engines, for instance, has been linked to the slow reproduction of large aquatic mammals.

Noise can also disrupt the social networks of whales, who depend on vocalisations to locate food and stick together. It can cause them to lose track of pod members and separate mother-calf pairs. Feeding and mating behaviours may be disrupted, affecting the sustainability of whale populations.

In addition, noise pollution has been linked to mass strandings, where droves of whales beach themselves. A 2009 study reported 136 documented mass strandings of beaked whales between 1874 and 2004, with all but ten occurring after the introduction of high-powered military sonar in 1950. Some investigations have expressly implicated sonar in these strandings.

The oil and gas industry's use of seismic surveys, which employ loud air guns, has also been identified as a contributing factor to mass strandings. These surveys create loud, frequent explosions that can radiate for miles underwater. A mass stranding of around 100 melon-headed whales in Madagascar in 2008 was attributed to seismic surveys conducted by ExxonMobil.

While the exact number of whale deaths due to noise pollution is challenging to calculate, it is evident that human-generated ocean noise is having a significant detrimental impact on whale populations.

Chemical pollution

Marine pollution is one of the biggest environmental threats to our planet, and whales are among the species that face its consequences. Chemical pollution is a significant aspect of this, with toxic chemicals entering the ocean and affecting whales and other marine life.

Sources of Chemical Pollution

Another source of chemical pollution is the use of pesticides and other agricultural chemicals. These chemicals can enter water bodies through runoff from agricultural lands and contaminate the ocean, posing risks to marine ecosystems.

Impact on Whales

The impact of chemical pollution on whales is profound. One of the main ways whales are affected is through the consumption of contaminated prey. Small fish absorb these chemicals, which are then consumed by larger fish, seals, and eventually whales. This process, known as biomagnification, results in the highest levels of toxins in top predators like orcas.

The toxins that accumulate in the whales' bodies can lead to various health issues, including cancer, immune system suppression, birth defects, and reproductive issues. The toxins are stored mainly in the whales' fatty tissue, or blubber, and when the whales break down this blubber for energy, the toxins are released into their bodies.

One well-known case is that of Lulu, an orca from the Scottish West Coast Community. Lulu died with toxic chemical levels 20 times the safe limit, and her body was considered toxic waste. Unfortunately, Lulu's story is not unique, and many whale populations are declining due to the impacts of chemical pollution.

Addressing Chemical Pollution

To address the issue of chemical pollution, several measures have been proposed and implemented. On a global scale, the Stockholm Convention, signed by 90 countries and the European Community, aims to reduce or eliminate the production, use, and release of persistent organic pollutants (POPs). Additionally, there have been calls for stricter regulations, improved waste management, and the banning of certain toxic chemicals.

Local initiatives, such as the Cap Cetacés research project by WWF France, also contribute to addressing chemical pollution. This project focuses on understanding the impact of invisible toxic and plastic pollution on cetaceans in the Mediterranean region.

Despite these efforts, chemical pollution continues to be a significant threat to whales and other marine life, highlighting the need for continued advocacy, research, and action to protect our oceans and the species that depend on them.

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