Our Dying Seas and the fate of the Toheroa – NZ’s Canary in the Coal Mine


In light of the current die-off happening at Waitarere & Hokio in the Horowhenua this week, see what has been happening to our oceans & shellfish stock NZ wide. The demise of these bottom feeders are, like the canary in the coal mine, the early warning signs of worse to come if preventive measures are not taken. Preventive however is not on any corporate radar unfortunately & it may well be too late now going by the information in this article at seafriends.org.nz  

EnvirowatchRangitikei


Never before have so few people done so much harm to the environment,
and over such large areas and in such a short time period as here in New Zealand. – Dr Floor Anthoni

Some 40 years ago the toheroa was New Zealand’s most loved icon, not only unique to our country but also big, and one could catch and eat it. The toheroa (Paphies ventricosa) is a large clam that lives in wave-washed beaches along NZ’s west coast from Wellington to North Cape. In the late 1970s it became protected by a reduced harvest season of only two days per year. Then it became fully protected. It was expected that its populations would recover within a few years but they did not. Instead their numbers dwindled further until today, it remains economically extinct.

toheroa and tuatua ecology Paphies spp

On left the native toheroa (Paphies ventricosa) (1) in the act of digging, and next to it the much smaller but similarly shaped tuatua (Paphies subtriangulatum) (2) and the small tawera or morning star (Tawera spissa), each having  its place and depth on the beach. The toheroa is found from Ninety Mile beach down to Auckland, around Levin and a pocket in the very south of the South Island. It burrows at mid tide, the best place to be for abundant plankton. By comparison the tuatua is found between low and spring low tide. Tawera burrows well below low tide in calmer sandy bottoms. Both tuatua and toheroa are active burrowers, capable of keeping up with the turbulent sand under waves.  


disappearing scallops
The scallop (Pecten novaezelandiae) is another NZ icon on the way out. Only twenty years ago, scallops were numerous and easy to gather but now entire scallop beds have disappeared (red marks on map) and some are not even recognizable. The shells have become small, stunted and empty of their delicious gonads (roe). The burrowed scallop photographed under water (picture below) has not reached legal size, even after ten years of growth. It takes normally 2-3 years to reach legal size. Its margins are stunted (blunted) and it has no content to eat.



New Zealanders did not realize that the toheroa was the first coal miner’s canary (whistle blower) to warn of something terrible happening to our seas. For if total protection could not save it, neither could marine reserves or any other fisheries regulation. It heralded the beginning of a new era, that of dying seas, culminating most likely in the extinction of Maui’s dolphin and the loss of most of our coastal fisheries.

READ MORE

http://www.seafriends.org.nz/indepth/shellfish_collapse.htm#toheroa

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