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WDC team at UN Ocean conference

Give the ocean a chance – our message from the UN Ocean Conference

I'm looking out over the River Tejo in Lisbon, Portugal, reflecting on the astounding resilience...
We need whale poo 📷 WDC NA

Whales are our climate allies – meet the scientists busy proving it

At Whale and Dolphin Conservation, we're working hard to bring whales and the ocean into...
Humpback whale underwater

Climate giants – how whales can help save the world

We know that whales, dolphins and porpoises are amazing beings with complex social and family...
Black Sea common dolphins © Elena Gladilina

The dolphin and porpoise casualties of the war in Ukraine

Rare, threatened subspecies of dolphins and porpoises live in the Black Sea along Ukraine's coast....
Minke whale © Ursula Tscherter - ORES

The whale trappers are back with their cruel experiment

Anyone walking past my window might have heard my groan of disbelief at the news...
Boto © Fernando Trujillo

Meet the legendary pink river dolphins

Botos don't look or live like other dolphins. Flamingo-pink all over with super-skinny snouts and...
Risso's dolphin entangled in fishing line and plastic bags - Andrew Sutton

The ocean is awash with plastic – can we ever clean it up?

You've seen pictures of plastic litter accumulating on beaches or marine wildlife swimming through floating...
Fin whale

Is this the beginning of the end for whaling off Iceland?

I'm feeling cautiously optimistic after Iceland's Fisheries Minister Svandís Svavarsdóttir wrote that there is little...
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Minke whale hunts stop in Iceland

Iceland’s commercial hunt of minke whales has ended for this year. The common minke whale is the...
Port River dolphins

New report reveals 100,000 dolphins and small whales hunted every year

When you hear the words ‘dolphin hunts’ it’s likely that you think of Japan or...

Australian Government to block Japanese whaling proposal

Japanese Government officials have reportedly confirmed that they will propose the resumption of commercial whaling...

Pregnant whales once again a target for Japanese whalers

Figures from Japan's whaling expedition to Antarctica during the 2017/18 austral summer have revealed that...

Did Icelandic whalers really kill a blue whale?

*Warning - this blog contains an image that you may find upsetting* They say a...

Icelandic whalers breach international law and kill iconic, protected whale by mistake

Icelandic whalers out hunting fin whales for the first time in three years appear to...

Doubts remain after Icelandic Marine Institute claims slaughtered whale was a hybrid not a blue

Experts remain sceptical of initial test results issued by the Icelandic Marine Institute, which indicate...

Japan set to resume commercial whaling

Reports from Japan suggest that the government they will formally propose plans to resume commercial...

End the whale hunts! Icelandic fin whaler isolated as public mood shifts

Here’s a sight I hoped never again to witness. A boat being scrubbed and repainted...

Norway increases whaling quota despite declining demand

Norway's government has announced an increase in the number of minke whales that can be...

Icelandic fin whale hunting to resume

Iceland’s only fin whaling company, Hvalur hf,  announced today that it will resume fin whaling...

SOS alert for whales off Norway!

I have to admit to bitter disappointment when I arrived in Tromsø, northern Norway, a...

Mayday Monday – Legacy Toxins and Bioaccumulation

Primary Threat #2: Legacy Toxins and Bioaccumulation

Chemical pollution is another major threat to the orcas: the Southern Resident orcas are one of the most contaminated marine mammal populations in the world. They are a long-lived top predator, which makes them incredibly vulnerable to pollutants that accumulate up the food chain. Their home in Puget Sound is very urban, and toxins that originate on land make their way to the rivers and coastal habitats where they are absorbed by tiny plankton – these plankton are eaten by small baitfish and work their way up the food web to the salmon that orcas eat. At every step in the food chain, the concentration of contamination is compounded, a process called biomagnification. 

Toxins of greatest concern are the “persistent organic pollutants” or POPs, such as the pesticide DDT, PCBs (a known carcinogen) and PBDEs, (flame retardants). Exposure to these chemicals is linked to disease in orcas because they depress the immune system and act as endocrine disrupters that cause reproductive problems. These chemicals are known as “legacy toxins” because of their tendency to persist in the environment. Both DDT and PCBs have been banned in the US, but are still present in alarming concentrations in whales’ blubber layer. Because these toxins are found in reproducing females, calves will continue to be exposed to – and accumulate – these same “legacy toxins” for generations to come. Young whales have particularly high toxin levels that they acquire from their mothers, who use their fat stores to help the growth and development of their calves. The health of new babies is compromised from the beginning because of this toxin offloading between mother and calf. The level of PCBs found in the blubber of Southern Residents greatly exceeds the level we know to be detrimental to other marine mammals. High levels of toxins play a prominent role in preventing them from increasing at the rate needed for recovery.

The three pods differ in their levels of each specific toxin: L and K have higher levels than J pod of DDT, which is more likely to occur off the California coast, indicating that these two pods spend more time feeding on prey there – an area not included in critical habitat but part of the proposed expansion. The National Marine Fisheries Service (NMFS) has collected fecal samples from the Southern Residents as they travel the outer coast, which could provide new information about their contaminant levels, but samples from the past three years have yet to be analyzed and the results made public.

While DDT and PCBs are banned in the US, chemical pollution is still an issue because of historic use, retention in blubber, and their use in developing countries where they still enter the ocean and circulate to west coast waters. Critical habitat will not directly help to remove threats associated with toxin exposure and accumulation, but will help manage the ongoing harmful human actions that affect the Southern Residents, and adds protection from any future activities that may result in more toxins entering their habitat. The severity and persistence of these toxins makes it all the more important that we take what actions we can to lessen other stressors.

Help us expand the Southern Residents’ critical habitat by signing our letter urging NMFS to act NOW.

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