UConn professor gives new insight into aquaculture, marine harvesting

11/07/08 - For University of Rhode Island students, going to the beach is just another day in the life. Sunbathers and surfers are frequently seen enjoying the scenic views and riding the waves rushing in with the tides. This may sound blissful, but on most days, mounds of seaweeds can be seen piled up along the shoreline and rolling around the shallow coastline. For Professor Charles Yarish of the University of Connecticut though, this is the highlight of a trip to the beach.

"I'm really a seaweed enthusiast," Yarish said.

Monday afternoon, a large crowd of URI undergraduate and graduate students, professors and colleagues welcomed the professor of biology and marine sciences to the URI campus.

Yarish spoke at the Weaver Auditorium in URI's Coastal Institute as part of the URI Ecological-Distinguished Speakers Series.

Yarish's work was entitled "Exploring Multi-Trophic Linkages Through Aquaculture Systems: Using Ecological Methods to Integrate the Cultivation of Seaweeds and Fish." It addressed the modern usage of aquaculture with the integration of seaweed as a means to increase quality and quantity of stock.

Yarish said "there is a good group [of people interested] in seaweed biology, fish biology and shellfish at URI."

Unaware to many, seaweeds have multiple uses, including food, animal feed, fertilizer, leather, cosmetics, textile and medicines. They are also a major source of phycocolloids, which are gelatinous compounds used in various products worldwide. The colloid industry alone is worth approximately $700 million.

According to a 2003 report on the composition of North American aquaculture, 78.1 percent is finfish, 20 percent is mollusks and 1.9 percent crustaceans.

The purpose of farming seaweeds along with other aquaculture produces is to "increase aquaculture without exacerbating nutrient levels of coastal waters," Yarish said. "We're trying to promote a balanced ecosystem management known as integrated multi-trophic aquaculture."

Professor Chris Lane, who will begin teaching biology at URI in the spring semester, said Yarish's presentation was a great addition to URI's outreach to other scientists because it is important "to learn about economics and industry and some of the ways we can mitigate the issues that connect with aquaculture, biofouling and nutrients in the water."

For 20 years, Yarish worked in mainland China to help implement a modernized aquaculture system that incorporated seaweed farming. While in Jiaozhou Bay in Qingdao, China, he observed green tides, which are caused by green macro algae linked to the presence of increased nutrient levels, otherwise known as eutrophication.

These green tides were affecting the finfish and shrimp aquaculture. With the help of government officials and native people whose livelihood depend upon the wellbeing of the aquaculture industry, Yarish introduced various species of seaweed into their farming methods. Kelp, for example, absorbs waste products that accumulate from sources such as shrimp farms, human influences and fish farms.

"Most Chinese production is seaweeds, shellfish and herbivores," Yarish said.

When seaweed is grown in the same vicinity as fish, the nitrogen content in the seaweed tissues reach a healthy level. This is because fish waste creates increased nitrogen levels in the water. When seaweed is added to the aquaculture system, ammonium levels are decreased in fish.

The overall effect is highly beneficial for the health of the fish and seaweed, as well as the farmers looking to make a decent profit.

Porphyra, commonly called Nori, or better known as the seaweed wrapping on sushi rolls, was first cultivated in Arieke Bay, Japan. As a result of its cultivation, Japan doubled its overall seaweed growth rate. The circulation of ocean water from up to 1,000 meters deep throughout the aquaculture systems implemented within this area also aided to the beneficial growth jump.

Today, many different species of Porphyra have been introduced into New England waters in efforts to recreate the quality of the seaweed grown in Japan, as well as create jobs for people and modernize North America's aquaculture industry.

"I'm very enthusiastic for New England, I see we have all the right [water] conditions [necessary for the growth of this seaweed species]," Yarish said.

"In our industrial practices, we're starting to take an ecosystem and integrative approach to manage our resources," said Leanna Heffner, a graduate student going for her Ph.D. at the University of Rhode Island Graduate School of Oceanography.

"I'm pleased we're starting to think in a more progressive way," she said.

Yarish has been a professor at UConn for 33 years, and he has introduced seaweed farming to South Africa, created similar aquaculture plans in Zanzibar and Southern Kenya, taught at the State University of New York at Stony Brook and at the Biologische Anstalt Helgoland in Germany, as well as at the University of Groningen in the Netherlands. Currently, he is in the process of implementing an integrated system working with kelp in Baja, Mexico.