Bitter medicine required

A109 Light Utility Helicopter flight with mayor Gisborne City from the air in November 2023.

The current toxic shellfish warning is another sign of poor land-use decisions. What we do on land ends up in the sea — poisonous seafood is the payback we get for abusing Mother Earth.

Algae and phytoplankton blooms are not just the result of shallow, slow-moving, warmer water but also the outcome when water is overloaded with runoff from the land — fertiliser, agri-chemicals, animal and human pollution, and silt.

Blue bioluminescence may produce cool photos, but it is deadly to dogs, and makes seafood toxic to humans.

In 2017 a Niwa scientist speaking about the increase in bloom events in lake, river and sea noted the Gisborne-East Coast region had not seen these events until that year, but said they were occurring more often around New Zealand.

The latest alert from the Ministry for Primary Industries says the paralytic shellfish toxins detected in Hawke’s Bay, Wherowhero Lagoon and Tolaga Bay are over the safety limit for food . . . at Tolaga Bay, 11 times over that limit.

Algae and phytoplankton blooms — and silt — affect (kill) sealife by clogging gills, smothering the sea floor, depleting oxygen in the water and reducing visibility.

Land, Air and Water Aotearoa says blooms “can be exacerbated by nutrient inputs from land-based sources” — and the biggest input here by far is the huge amount of silt washed off the land.

Why? Because human activity stripped the land of its protective covering — land which is hilly, geologically young, of soft sedimentary composition with no harder rock to resist the erosive force of rain.

Human activity — roads, buildings, farming and forestry — all contribute to the ongoing disturbance of the soil, resulting in rivers of silt washing out to sea every time it rains.

The warning about shellfish is just another symptom of how we have mistreated the land, and is a clear lesson in how everything is symbiotically linked.

We humans caused this deadly disease — we are also capable of coming up with the cure.

The cure will be bitter medicine — do we have the stomach to fight our leaders, governments and big business for a better future? That is the single most important question.

Roger Handford