NEWSLETTER May 2005
In this newsletter
· Minister’s Decision on QMS for seaweed
· Harvesting Trials underway for Ecklonia radiata
· Beware this seaweed!
· Research - Culture of the native red seaweed Gigartina atropurpurea
· Department of Conservation Coastal and Marine Conservation Policy
DECISION ON SEAWEED IN THE QUOTA MANAGEMENT SYSTEM
A small group of dedicated SANZ members worked long and hard to submit to the Ministry of Fisheries that not enough information was available to reliably introduce seaweed quotas, without jeopardising the seaweed stocks in New Zealand coastal waters.
The Minister of Fisheries decision not to introduce 7 seaweed species into the QMS for the 2005 year is welcomed by SANZ Inc.
Chairperson, Jill Bradley says –
Already, a valuable research trial is underway – directed by Dr Tim Haggitt PhD, and sponsored by Ocean Organics Ltd.
The intension and purpose of the research is to develop a sustainable harvesting strategy for the laminarian alga Ecklonia radiata.
Over a 2-3 year period, the research with specifically address:
· Determining the standing stock of E. radiata for a given area of seabed
· Quantifying the impacts of harvesting (cutting) natural populations, including
a) regeneration of harvest areas
b) effect on other marine species.
This information will be used to:
· Determine when E. radiata should not be cut and what size areas should be cut
· Develop a harvesting / reseeding model for E. radiata.
The full scope of the trial is available to SANZ members on application.
SANZ Inc would encourage more trials of this nature, especially for the 7 seaweeds proposed to enter the QMS (sometime). Those seaweeds are:
Ø agar weed (Pterocladia lucida, Pterocladia capillacea)
Ø bladder kelp (Macrocystis pyrifera)
Ø brown kelp (Ecklonia radiata)
Ø bull kelp (Durvillea spp)
Ø gracilaria weed (Gracilaria chilensis)
Ø lessonia (Lessonia variegata)
Ø porphyra (Porphyra spp)
Beware this seaweed !!
Caulerpa taxifolia is native to the tropical Atlantic, Pacific, and Indian Oceans, and its attractive growth form has made it popular with people who keep saltwater aquariums. It has become a major problem, however, because of a robust and cold-tolerant strain developed at Stuttgart Zoo under artificial aquarium conditions. This strain was then transferred to Monaco. It can grow up to 8 cm a day, tolerate complete darkness, and survive out of water for up to 10 days – and regrow from tiny fragments. It can grow at depths of between 3 and 35 m, though it has been recorded at 100 m.
The "normal" form of this tropical seaweed has specific growth requirements for warmer water, cannot tolerate exposure to air or long periods of dark, and has a much more restricted ecological range.
A small amount of C. taxifolia was recently found in a saltwater aquarium in Auckland, causing a great deal of concern. Was it the tropical or aquarium strain? Did it occur elsewhere in New Zealand? Was there a risk of fragments being released into the environment when aquarium owners cleaned their tanks?
Visit NIWA site to see the answers to these questions: http://www.niwa.co.nz/pubs/mr/archive/ncabb/abb/2002-01/green
Department of Conservation : Marine and Coastal Conservation
“Marine conservation is an important responsibility of the Department of Conservation.
DOC is responsible for marine reserves and for marine mammals such as dolphins, whales, sea lions and fur seals.
The Department also administers the regulations for the whale and dolphin watching industry.
Less than 0.1 per cent of New Zealand's marine environment is currently protected, compared to about 30 per cent of its land area.
The Department is also responsible for the New Zealand Coastal Policy Statement which promotes the sustainable management of the natural and physical resources of the foreshore, seabed, coastal water and airspace from the high tide mark to the 12 nautical mile limit.”
Culture of the native red seaweed Gigartina atropurpurea
Gigartina atropurpurea is a leafy-bladed red alga which grows from the intertidal zone to deeper than 10 m throughout New Zealand. It contains valuable polysaccharides called carrageenans that are used as suspension agents in dairy products worldwide. Results from joint trials by NIWA and Industrial Research Limited (IRL) during 2000-01 suggest that Gigartina may have potential as a seasonal crop for export of carrageenans.
Trials to determine a farming and harvesting strategy included ascertaining the importance of life stage, plant variety (intertidal vs subtidal), and the effect of timing and frequency of harvesting on growth of experimental plants. The trials were held at Bruce Hearn’s Apex Marine Farm in the Marlborough Sounds and at Mahanga Bay, NIWA’s aquaculture research facility in Wellington.
The results were encouraging: farmed plants grew as rapidly as, and often better than, control plants in the wild. The main growing season was spring when, on average, plants grew to at least 300% of their original weight in as little as 44 days. There was also significant growth in autumn. Harvesting twice a month gave better yields than harvesting only once during a season or the controls, suggesting that frequent harvesting accelerated growth.
For farming to be feasible, techniques for hanging seaweed lines between mussel droppers must be developed to enable effective integration of the two species on the same line without compromising growth or harvest of either. Methods for reliably seeding spores on ropes for out-planting must also be developed before culture can become a reality.
This work was funded by the Foundation for Research, Science and Technology (contract C01X0002).
Mike Page (NIWA)
Ruth Falshaw and Sally McNeill (IRL)© Copyright 2005 by NIWA