Sam Judd

Comment on the environment from columnist Sam Judd

Sam Judd: Canaries in a salty mine

Comb Jellyfish have conquered marine environments to the detriment of tourism, fishing and fun. Photo / Thinkstock
Comb Jellyfish have conquered marine environments to the detriment of tourism, fishing and fun. Photo / Thinkstock


As we continue to haul out resources from our lucrative salty mine - the ocean - science has found the dead canary - thousands upon thousands of slimy globules.

Jellyfish are blooming exponentially and threatening our ability to enjoy and exploit the ocean.

Thought to be harmless if not for the odd irritating sting, jellyfish are in fact the cockroaches of the sea - termed so because they thrive in damaged environments, which is why their proliferation is so worrying for us.

In fact they are responsible for thousands of human deaths annually and those numbers are rising steadily. They kill about 1000 times more frequently than shark attacks worldwide and in some places, such as Hawaii, lethal breeds of "box" jellyfish are the unwanted new arrivals which threaten the crucial tourism market.

The gelatinous troops are semi-transparent beings, that feed on other fish and scavenge food, using poisonous tentacles to stun their prey.



It is fairly common knowledge that our waterways in New Zealand are sick and getting sicker. As we continue to push to increase production on intensively used land, more and more nutrient-rich fertiliser and effluent enters our waterways. This provides nourishment for the small organisms on which jellyfish feed and the slimy army devours everything in its' path.

These small organisms, such as phytoplankton, frequently die en masse, sinking to the ocean floor where their bacterial degradation reduces the amount of oxygen in the seawater and creates a "dead zone". Jellyfish - unlike fish and shellfish - thrive in oxygen-deficient environments and conquer all - disrupting the food chain and making important fisheries unviable.

Such "dead zones" have doubled each decade since 1960- due to the heavy amounts of nutrients that activities such as dairy farming pump into the ocean- and it is getting worse.


- Source: National Science Foundation


Fonterra has finally admitted that their activities are damaging our waterways and now support clean-up initiatives - but without a huge concerted effort - this could be too little too late.

It is not just the rivers that suffer but also the coastlines, which impacts the fishing, aquaculture and tourism industries.

If we want to continue our economic honeymoon with tourism (which employs one in ten New Zealanders and contributes $9.5 billion to our export economy - ahead of dairy which is at $9 billion) we need to keep our beaches clean, open to swimming and supporting the existence of the fish that we love to catch and sell.

In the Black Sea, now thought to have passed an ecological tipping point, scientists have found that 90 per cent of the biomass is jellyfish- the army is hunting other species to extinction. Meanwhile, humans also harvest fish towards extinction, taking away competitors for the jellyfish.

If anyone out there wants to take on the slimy army and get involved with repairing our damaged waterways- we run corporate teambuilding events that plant out the riparian strip with native trees. This creates a natural buffer zone that sucks the damaging nutrients out of the water, cleaning it up before it enters the ocean. You can contact us here.

If you prefer not to get your hands dirty but still want to swim at the beach without being stung and eat fish, then you can donate $10 towards a native seedling that will be planted by school students here.

For more information, visit these interesting sites:

* Commonwealth Scientific and Industrial Research Organisation (Australia)

* National Science Foundation (USA)

* Jellyfish Facts

* Human shadows on the seas (New York Times article)

* Scientists claim increasing world jellyfish population is bad sign for planet (The Tech Herald article)

Sam Judd is Co-founder and Events director for Sustainable Coastlines - a registered New Zealand charity that motivates people to look after their coastlines.

Photos / Thinkstock, Sustainable Coastlines

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