Irish Moss

BIO Scientist Develops Cultivation Method for Unique Strain of Irish Moss

BIO scientist Glyn Sharp has developed an innovative technique for cultivating a unique strain of Irish Moss found only in the semi-sheltered waters at Basin Head, Prince Edward Island. Continued success in grow-out, harvesting and re-seeding would help diversify the livelihood of local oyster farmers, and create a new supply of carrageenan for world markets.

The Team

Glyn Sharp is a Research Biologist with the Invertebrate Fisheries Division of the Department of Fisheries and Oceans who works out of the Bedford Institute of Oceanography. Sharp began to take an interest in Basin Head Chondrusin 1989 when he learned that a unique strain was growing in a basin in Prince Edward Island. His research had been focused on nearshore beds of marine plants commercially harvested in western P.E.I. He became interested in developing an aquaculture method for cultivating the sea plant so it could be raised and harvested in the wild, as opposed to in tanks. He also saw the importance of protecting the unique habitat that had given rise to this particular strain of Chondrus.

Dr Thierry Chopin of the University of New Brunswick at St. John has led the investigation of the physiological characteristics of this strain in a world-class biochemical laboratory.

Bob Semple, an underwater photographer and marine biology technician, has worked with Sharp since 1990. Bob has extensive knowledge of the commercial marine plant beds of Prince Edward Island.

The Rationale

This particular strain of Irish Moss is 50% more valuable than the common variety of Irish Moss because it yields 50% more of the gelling-type (kappa) carrageenan used in processed milk products such as ice cream and pudding. (The carrageenan that is normally harvested is a mixture of kappa and lambda carrageenan. While the latter does not gel in water, through interacting with proteins it acts as a dairy products stabilizer.)

The Challenge

With the potential value of this strain of Irish Moss established, the challenge was to devise a cultivation method that could be replicated elsewhere (this strain had only grown at Basin Head, PEI), with the labour-saving efficiencies that would be required for commercial grow-out and harvesting.

Among the challenges were:

• Previous attempts to transfer the sea plant from Basin Head to other sites on the island had been unsuccessful.
• The common belief was that Irish Moss could only be grown in tanks. Cultivation was unproven.
• Since the Chondrus was free-floating (it was not attached to the bottom like other sea plants) a method had to be devised for holding the plants in place.
• The grow-out technique had to be accomplished with no human handling until harvesting time.
• Harvesting and re-seeding would have to be accomplished with minimal human effort.

• The team had to identify the habitat conditions required for grow-out, and replicate them at the selected sites.
• It was vitally important to protect the only known supply of this particular strain of Chondrus.

The Solution

In 1995, Sharp transferred the plants to five locations on the western end of the island. After experimenting with nets and bags, and hanging the plants from buoyed ropes, he finally set them in the polyethylene socking used by mussel growers. (Fig. 1 –Socking Method)

In one experiment, in 1998, Sharp abandoned the notion that it was necessary to hang the Chondrus-stuffed socking from longlines (Fig. 2 – Hanging Technique) in order to expose it to sunlight from every direction. Instead, he laid the socking on the bottom, weighted by cinder blocks at either end of the line. (Fig. 3 – Bottom Technique) When Glyn Sharp and Mr. Semple returned in the spring to thin the growth, the socking was nowhere to be found due to ice movement… until it was relocated in the fall! The fact that growth had continued unimpeded, and there was little or no fouling of other plants or animals despite the lack of thinning, boded well for cultivation.

Meanwhile, Basin Head was on track for designation as a Marine Protected Area (because of the rarity of the sea plant), and this further motivated Sharp to transplant the Irish Moss elsewhere. The management plan only permits the removal of one ton per year, reinforcing the need to develop seed stock at another location.

Grow-Out Criteria

In selecting the pilot sites, Sharp ensured they conformed to these criteria:

• shallow water areas
• no shallower than one metre at low tide,
• maximum water depth of five metres,
• semi-sheltered waters,
• salinities above 20 parts per thousand,
• good water circulation, and
• temperature of at least 20 degrees in the summer.

Sharp and Semple continue to study the characteristics and growth of the unique strain of Chondrus crispus in tanks at the Bedford Institute of Oceanography.

Harvesting Method

Next, Sharp set about identifying a method to automate the process of filling the socking, and he teamed up with Eric Wagner, an oyster farmer in Malpeque. Wagner discovered a Nova Scotia-designed mussel-socking machine that would enable him to seed 20 kilometres of socking in one day. The machine stuffs special webbed tubing with pieces of moss at a rate of 300 feet per minute. Harvesting and re-laying for the next growth period would take place at the same time.

On retrieval of the mature sock, the excess growth on the outside of the sock is cut with a circular blade.

The specialized culturing process Sharp and his colleagues have developed over the years has been supported by the Prince Edward Island Department of Fisheries, Aquaculture and the Environment, the Atlantic Canada Opportunities Agency, Department of Fisheries and Oceans, and Human Resources Development Canada.

Projected Growth

In the summer of 2000, Sharp reports, the farmed sea plant grew by a rate of 4 to 6% per day.

Based on the recent rate of growth at the five pilot sites in western PEI, Sharp figures that two more growing seasons (May to October) are needed to amass enough Irish Moss (10 tons) for Wagner to begin growing in commercial quantities. He expects that Wagner will launch his commercial operation towards the end of 2002. Fifty tons are projected for the end of the first two growing seasons in August, 2003.

Commercial Interest

So far, two organizations have expressed an interest in purchasing the unique strain of Chondrus crispus: Brittany-based Centre d’Etude et de Valorisation des Algues, the research and development arm of the seaweed industry in France, and Acadian Seaplants Ltd. of Dartmouth.

Sharp notes that the socking technique is also suitable for other seaweeds including Gracilaria, which yields the chemical, agar. In 2001, the grow-out method will be tested in the Bay of Fundy with dulse (Palmaria palmata). While Wagner’s operation will be initially geared towards supplying Canadian growers, Sharp says it should also be possible to grow Chondrus cripsus and other sea plant species outside Canada, given the right conditions.

Last Modified: 2005-10-18

Important Notices