In your front-page lead story of January 26, Cathy Webb of Seafood NZ says “algal blooms have been a health issue since 1993. They are naturally occurring and not as a result of pollution, rainfall, etc.” This information is incorrect and raises questions over the validity of science by industry representatives.
MPI.govt.nz states: “Nutrient pollution from human activities can make the problem worse. This leads to blooms occurring more often.” Nutrient pollution includes human sewage and agrochemicals — fertiliser from farming and forestry. Run-off may be partially responsible for this unprecedented rise in occurrence, particularly in years of high rainfall. Our heaviest rains have coincided with both spring and autumn applications of fertiliser and other agricultural chemicals.
Higher concentrations of glyphosate in water also correlates with increased cyanobacteria, according to studies in the Baltic Sea. Glyphosate is widely used both in farming and forestry as well as in an urban setting in New Zealand. In the 1990s it became the most profitable pesticide ever to appear on the global market. Since the expiry of the original patent later that decade, it has been cheaply made in China and its use has increased exponentially worldwide.
In NZ the EPA recommends for glyphosate: “Keep away from streams, lakes or ponds. Do not put down stormwater drains” — yet its use is continued by contractors to GDC to control vegetation in drainage ditches.
Our oceans and seafood will not be healthy until we adopt safer agricultural and forestry practices.
Susie Lees
