HARVESTING TRIAL IN NEW ZEALAND
BULL KELP - see synopsis below or go to
FARMING TRIALS FOR NATIVE RED SEAWEED, Gigartina atropurpurea
REPORT FROM U.S.A. - Aqua culture, re-seeding
COMMUNITY MODIFICATION BY THE SOUTHERN BULL KELP Durvillaea antartica
Kelp Growing Plan a First
HARVESTING TRIAL IN NEW ZEALAND
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
- Quantifying the impacts of harvesting (cutting) natural populations
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
The full scope of the trial is available to SANZ members on
- Develop a harvesting / reseeding model for E. radiata.
top of this page
SELF-REPLACEMENT AND COMMUNITY MODIFICATION BY THE
SOUTHERN BULL KELP Durvillaea antartica
David I. Taylor,
David R. Schiel
Research Group, School of Biological Sciences, University of Canterbury,
Private Bag 4800, Christchurch 1, New Zealand
ABSTRACT: Stands of
the southern bull kelp
provide considerable biomass and a major habitat in the lower intertidal zone
of exposed shores on the austral land masses. Whiplash effects of adult fronds
(up to 10 m long) can affect recruitment, growth and survival of understorey
species and potentially large brown algal competitors, thereby affecting
community development. In southern New Zealand,
is one of several
species of large brown algae inhabiting the low intertidal zone. Effects of
its canopy and its associated understorey coralline algae on community
development were tested at 2 sites (Moeraki and Kaikoura) at different times
of year between February 1999 and October 2001. Removal of
surprising results compared to most studies where canopies of large brown
algae were removed. The greatest initial recruitment of bull kelp occurred
beneath intact canopies, usually in areas where corallines were removed.
Recruitment was highly variable through time, with peaks occurring in June and
October (austral winter–spring), depending mostly on when canopies were
removed. There was an order of magnitude difference in recruitment between
sites. The cover of turfing coralline algae, however, increased in all canopy
removal treatments. A major source of mortality of young recruits was grazing
by the herbivorous fish
Its distinct grazing marks were seen on recruits, almost exclusively outside
the canopy of bull kelp where 80% of recruits were grazed. We show that
has the ability to
recruit beneath adult canopies, but that survival and growth ultimately depend
on the extent of canopies, underlaying benthic algae and escapes from grazing
by herbivorous fish.
Large brown algae
dominate many marine rocky shores world-wide, providing biomass, food and
biogenic habitat that support most inshore species. Although many species of
algae, particularly those of the order Fucales, are desiccation-resistant and
occur throughout the intertidal zone, the large and dense stands usually begin
along the intertidal–subtidal fringe (Stephenson & Stephenson 1972). Here,
aerial exposure occurs only during the lowest of tides, but on high-energy
shores, wave splash ameliorates this effect. As few of the species that occur
at this fringe can survive either higher in the intertidal zone (cf. Schonbeck
& Norton 1978) or lower in the subtidal zone (cf. Choat & Schiel 1982, Chapman
1995), this habitat is likely to be unique in the combination of processes
that structure and maintain it. If this is the case, general models accounting
for community structure (Menge et al. 1997) will require modification.
Furthermore, a general understanding of structuring processes must include
regional or global differences in the important taxa (Menge & Branch 2001).
One of the largest
species of algae in the southern hemisphere occurs at the intertidal–subtidal
fringe of exposed shores. The southern bull kelp
is abundant on most
land masses at latitudes between 45 and
including Tasmania, Chile, New Zealand and the
islands (Hay & South 1979, Santelices et
1980, Santelices 1990a). This species is the largest
of the order Fucales (Hurd 2000) and is surpassed in size only by a few of the
largest laminarian algae. Fronds of this species can reach 10 m in length,
while their biomass reaches up to 80 kg m–2
et al. 1980, D.R.S. unpubl. data). Its positive effects on communities include
the provision of habitat for grazing invertebrates that reside in and around
hold fasts of adult plants (Hay 1977, Santelices 1990a, Edgar & Burton 2000).
For example, Edgar & Burton (2000) found 23 macro-invertebrate taxa associated
holdfasts on the
subantarctic Heard Island.
can also reduce or
eliminate other species through the whiplash effects of its fronds (Santelices
et al. 1980), leaving only a few species of tough foliose and coralline algae
intact near canopies of
Unlike Chile, however, where most of the potentially competing species are
laminarian algae, particularly the tough
(Santelices et al.
1980, Santelices & Ojeda 1984, Santelices 1990a), southern New Zealand has a
rich flora of fucalean species as well as a wide variety of red algae in the
lowest intertidal zone (Naylor 1953, Hay 1977, Schiel 1990, Nelson 1994,
Schiel et al. 1995).
exclusively at exposed, outer coast sites, occasionally intruding into
semi-exposed areas (such as behind headlands), but never into sheltered areas
(Santelices 1990a, Taylor & Schiel 2003). There are usually few other foliose
algae present, except hardy turfing coralline and other red algae, in the
vicinity of adult bull kelp. Recruitment can be extensive. In southern New
Zealand, Hay & South (1981) found that dense recruitment occurred in patches
where plants were removed. This tended to be seasonal because in southern New
austral autumn and winter (April to September) (Hay 1977) and greatest
recruitment occurs during late winter–early spring.
Algal canopies can
affect spore dispersal, light and nutrient supply to areas below, and the
whiplash of fronds and the extensive areas occupied by holdfasts can pre-empt
successful recruitment (Kennelly 1983, Dayton et al. 1984, Santelices & Ojeda
1984, Schiel & Foster 1986, Foster & Schiel 1987, Schiel 1988, 1990,
Santelices 1990b, Connell 2003a). Consequently, large brown algae often
recruit poorly beneath adult canopies compared to gaps outside them. For
example, Santelices & Ojeda (1984) found that canopy effects and grazing
combined to inhibit recruitment of
Bory in central
Chile. For multi-species assemblages, however, much of our understanding of
the effects of large brown algae canopies comes from subtidal studies. For
example, Dayton et al. (1984) followed demographic patterns of populations in
southern California over a 10 yr period, removed canopies and seeded areas
with sporogenic material of several algal species. They found a dominance
hierarchy for light competition determined by adult canopy height, but a
trade-off in the ability of higher canopies to withstand wave stresses. Of
overriding importance, however, were the life-history constraints such as
dispersal abilities and growth rates that determined the ability of each
species to invade and persist under canopies of other algal species.
between recruitment of large brown algae and the corallines that occur beneath
them is unclear. Coralline algae, a common feature of the understorey in lower
intertidal and subtidal habitats, have been found both to inhibit the
recruitment of some species and facilitate others (Connell 2003a,b). For
example, Camus (1994) suggested that encrusting coralline algae reduced
in northern Chile
by shedding epithallial cells. In other studies, turfing corallines
facilitated recruitment of fucoid algae by providing suitable micro-habitat
conditions (Brawley & Johnson 1991, 1993, Benedetti-Cecchi & Cinelli 1992).
Here, we seek to elucidate the structuring processes in one of the most
dominant and extensive assemblages in southern New Zealand (Nelson 1994). We
test the effects of
understorey corallines and the influence of different timing of disturbances
on algal community development. These are then discussed with reference to the
prevailing understanding of these processes in other related assemblages.
Note: The materials and methods
section is available as part of the full paper, also the intra-specific and
interspecific sections - full
paper PDF click here.
appears to dominate
these highly disturbed environments by arriving and recruiting in great
numbers near adult canopies. We found that this is most likely to occur when
free space occurs during winter and, because of winter storms, this is the
time when free space is most readily available.
canopies appears to
modify the understorey community by suppressing understorey turfing coralline
algae and excluding all other species of large brown algae.
References available as part of full paper.
top of this page
Bull Kelp- From filaments to fish food for a habitat-forming
David Taylor, Marine Ecology Research Group, School of Biological Sciences,
University of Canterbury, Christchurch, New Zealand, email:
"My research has explored some of the processes determining its
distribution along intertidal shores. In particular, I have examined
factors affecting the growth and survival of different life stages across
gradients of wave exposure."
Click here to read the paper Bull Kelp - David Taylor
IRL Research into seaweed farming
Article from Industrial Research Ltd website
9 January 2006
Scientists from Industrial Research and NIWA (The National
Institute of Water and Atmospheric Research) have achieved the successful pilot
scale production of seaweed from spores for the first time in New Zealand.
Many years of painstaking effort have gone into finding the best
conditions for commercially growing red seaweed (Gigartina atropurpurea) in this
country, Industrial Research scientist Ruth Falshaw says.
The seaweed spores are carefully put on three metre strings and
placed in the clear blue waters of the Marlborough Sounds at the top of the
South Island. Industrial Research has discovered several new and exciting
polymers, such as agars, carrageenans and fucans from New Zealand seaweeds, but
the issue is always obtaining commercial quantities of raw material.
Developing a seaweed farming industry, which does not compete as
a commodity product but sells on added value is the project aim, Ruth Falshaw
says. A whole new seaweed growing industry could spread to the mussel farms in
the Marlborough Sounds if this project is successful.
“Our ultimate aim is to make high value pharmaceutical products.
“I think the way we need to go is to add value. We’re not going to go far
sending containers of seaweed overseas, we want to be looking at things like
cosmetics, nutraceuticals and pharmaceuticals,” Ruth Falshaw says.
Industrial Research and NIWA want to develop a seaweed industry
in New Zealand, but there have to be sufficient stocks available for
commercialisation to proceed, she says. Once transferred, spores grow at a rate
of around three millimetres per day and suffer little competition from other
Initial trials have been preparing red seaweed for food industry
applications, as there is a ready made market for this area. Applications
include use as thickening and stabilising products, and use in the medical area
is also being explored.
“I have people overseas who are interested in buying this
material, but they need to know that there is a sustainable, reliable harvest
before they can consider buying it,” Ruth Falshaw says. “We are just on the cusp
on moving to a commercialisation phase for this.”
The quality of the New Zealand product is comparable to that
received from South America, commercial tests have shown. Seaweed aquaculture is
widespread in the tropics, but little is undertaken in temperate areas. And in
South America where they collect seaweed from the wild, they are at the mercy of
what grows naturally.
“I have people in Ireland and the United States who say once we
have 20 tonnes of seaweed available then come and talk to us,” Ruth Falshaw
Fellow Industrial Research scientist Susie Carnachan says one of
key results of their research has been to discover that pruning seaweed twice in
a season produces more biomass than pruning it just once. “The more you cut them
back the more they grow.”
So far the scientists been successful at growing male and female
plants, but have not been successful with tetrasporic (or non-sexual) plants and
are continuing research in this area.
for more see -
plan a first
The success of an unusual New Plymouth experiment in kelp growing is
likely to open the way for
major environmental projects along the New
The research project is proving that it is possible to artificially grow
kelp, which is among the
most important sea-floor vegetation. Scientists
are now growing the plant on
dozens of specially made concrete blocks
placed in strategic areas
off New Plymouth.
When the vegetation has reached a suitable size, the blocks will then be
relocated to other parts of
the Taranaki foreshore in an effort to
create new kelp "forests" -
perfect habitat for a wide range of marine
life. "It's like a potted
plant industry in a way," said oceanographer
Peter McComb, in New
Plymouth last week. We think it has real potential.
If this research project works, the results could have a very wide
application - from people
transplanting the kelp to help enhance their
favourite dive spots, to
re-establishing it in coastal areas that have
been devastated by storms."
The research project is the initiative of the joint venture Shell, Todd
and OMV which owns the
Pohokura offshore gas field that is about to be
developed in Taranaki.
During the resource consent process for the
project, concern was
expressed that the construction of offshore
production platforms and
laying of pipelines would damage existing kelp
plantations in the area. At the joint venture's request, special
conditions were built into
the consents requiring a kelp reseeding
project. Once the Pohokura
field has been developed, the concrete blocks
carrying the young kelp will
be placed on the sea floor in the area.
The project is being carried out by Hamilton-based marine consulting and
research company ASR Ltd in
conjunction with the Pohokura field's
operating company Shell Todd
Oil Services. The Taranaki Regional
Council, Department of
Conservation, Niwa and Port Taranaki are also
Dr McComb said research showed that kelp spores travelled distances of
no more than five metres,
which meant that natural colonisation of the
marine plant was a slow
process. The project is experimenting whether
this can be accelerated.
Dozens of concrete blocks have been placed in
an existing kelp forest near
one of the islands off Port Taranaki, and
more have been placed among kelp off the Waiwhakaiho River. Dr McComb
said success has already
been achieved at both areas. "The kelp is
growing really well on the
blocks - some of the juvenile plants are
already more than 6cm high.
The next step is to see if these blocks can
now be relocated.
The project is also trialling artificial kelp seeding. More concrete
blocks were placed in large
tanks at a paua farm at Port Taranaki, and
after kelp was artificially
stimulated into releasing spores, the blocks
were then transferred on to
the harbour floor. Unfortunately, an algal
bloom occurred in the
harbour some weeks ago and smothered the spores,
Dr McComb said, and that
part of the project had to start again. "But we
know we did get a good spore
release in the artificial seeding. So it
looks like the project will
come down to deciding which way is the most
efficient - the natural
seeding or the artificial way."
This spring, scientists also intend placing reproductive kelp into
crayfish pots and locating
it on barren reefs off New Plymouth, to see
if the plant is capable of
naturally transferring to a new site. Dr
McComb said research showed
that there were no large kelp forests in the
Pohokura area. Rather, there
were numerous patches of it. "Kelp is a
really important primary producer in the ocean. It's like grass, in that
everything feeds on it. In
areas where there are large kelp forests,
there are 100 times the
density of marine life species, because it
provides food, shelter and habitat."
Taranaki Daily News,
top of this page
REPORT FROM U.S.A. - Aqua culture, re-seeding
Rockweeds (Fucus spp.) and knotted wrack (Ascophyllum spp.) are two of the
most commercially important seaweed species in the Northeast. Thousands of tons
of these seaweeds are harvested each year for use as fertilizer, animal feed,
packing material for the lobster and marine baitworm industries, and the
extraction of algin. Several other countries have also expressed interest in
harvesting large quantities of these species from the coast of Maine. With the
possibility of increased harvesting activity, many are concerned about the
effects of overharvesting.
Since Ascophyllum and Fucus are found mainly in open coastal and estuarine
habitats, they are susceptible to over-harvesting. Robert Vadas, researcher at
the University of Maine, is studying how knotted wrack and rockweeds colonize
and attach themselves to rocks in order to determine the best harvesting
methods, as well as appropriate rates and amount of harvesting, to avoid
damaging the resource.
Vadas found that knotted wrack, which lives 20 to 25 years, should be cut 12
to 15 inches above the substrate where it is attached in order to maintain a
healthy plant. If the plant is cut or broken too low, it does not regenerate
well. He also discovered that knotted wrack does not "recruit" easily (
i.e., the zygotes or early stages of the plant do not stick well to rocks). This
could help explain its inability to recolonize or reseed itself.
A species of rockweed (Fucus distichus subspecies evanescent) lives only two
to five years and recruits much more readily. By comparing the recruitment and
attachment mechanisms of knotted wrack zygotes to those of Fucus species and the
effects of water movement on recruitment, this study could provide crucial
information for reseeding denuded or overharvested shores.
University of New Hampshire (UNH) researchers Arthur Mathieson and Subhash
Minocha are studying the kelps, another ecologically and commercially important
group of seaweeds. These large brown algae provide substrata and cover for a
host of marine organisms and are another important source of algin. UNH
researchers are exploring the genetic basis for the inheritance of desired
traits by the kelps Laminaria longicruris and Laminaria saccharine, information that is essential
to their cultivation. In addition, these scientists are seeking to identify
genetic markers for desirable traits, indicators that will aid in the selection
of the strains most suitable for aquaculture.
top of this page
page last updated November 2005