$$$eaweed
Who harvests seaweeds?
Written by: Dr. Carol Hopper Brill and Lisa Ayers Lawrence, Virginia Sea Grant, Virginia Institute of Marine Science
Summary
Using data from the United Nation's Food & Agriculture Organization and TradeDataNet, students will explore harvest and production data of seaweed around the world.
Objectives
- Compare the world harvest of different types of seaweed.
- Evaluate and graph seaweed production harvests.
- Interpret variation in global seaweed production.
Vocabulary
Algae, Phycocolloids, Agar, Alginate, Carrageenan
Introduction
Seaweed has been traditionally harvested in Europe, Asia and the Pacific
Islands for thousands of years, and today harvesting
Seaweed has
been traditionally harvested in Europe, Asia and the Pacific Islands for thousands of years,
and today harvesting seaweed is big international business. Not only are seaweeds
harvested for direct consumption of the plant itself, but also for the
intriguing and functional chemicals or "natural products" they produce. Many of these
compounds have application for human use. Chemicals derived from seaweeds are
used in medicines, food and beauty products, and industry. That's right, the
ice cream and chocolate milk in your fridge, the lipstick in your makeup bag,
and even the toothpaste you brushed your teeth with this morning may all be
made with seaweed extracts.
How does seaweed
end up in both whipped topping and paint? Most seaweeds are algae -- aquatic plants that lack roots, stems or leaves. Algae are divided
into three main types: red, brown and green. From each of these types of algae,
scientists have been able to identify and isolate compounds that can make foods
creamier and paint thicker. Red and brown algae produce phycocolloids ("phyco" = seaweed, "colloid" =
glue) that include agar, alginate and carrageenan.
Green algae produce the antioxidant beta carotene which is a precursor to vitamin A.
The use of these
compounds in food products took off in the second half of the 20th century as
the demand for prepared foods increased. Compounds like carrageenan improve the quality of the food and help to stabilize it, making the item more
appealing to consumers. Currently the import and export of seaweed is a $200
billion business, with the United States importing nearly $50
billion worth each year. And as more nations become developed, the need for
more prepared foods and pharmaceuticals will increase the demand for seaweed
compounds.
To meet this demand,
selected marine algae are grown, harvested and processed on large scales around
the globe. In 2002, farmed seaweed
production was 88% of total seaweed supplies (FAO
Report). Progress does have a price
tag, however. Some
of the most productive seaweed species have been transplanted outside their
natural range. In their new environment, they are "introduced" or "alien" species.
Despite the best intentions and efforts of researchers & industry, these
species sometimes escape into the wild (through the aquarium trade,
aquaculture, ship ballast waters and boat hulls) and
have serious ecological impacts. Hawai'i reports
problems with invasive
algae species and is trying different
methods to prune back algae growth affecting coral reefs.
Although seaweed
farming is an ancient practice, innovative methods are always being explored.
Bridgeport Regional Vocational Aquaculture School in Connecticut has been
working with Connecticut Sea Grant researcher Dr. Charles Yarish to improve aquaculture techniques for the red
alga, nori (see picture above). Students and
scientists are cultivating nori next to salmon
aquaculture pens. The red algae remove from the water excess nutrients produced
by the fish, and in turn use those nutrients to grow.
Who harvests and
imports seaweeds? The activity below will help you answer this question.
Data Activity
DATA ACTIVITIES
We'll start by using
the United Nations Food & Agriculture Organization (FAO) statistical site
to research fishery production of marine algae around the world. A report by
Trade Data International provides charts on countries that import and export
algae and the average import prices.
Who Harvests
Seaweeds?
What were
reported world seaweed harvests in 2001? Using the FAO Stats we can investigate
the world harvest of seaweeds:
- From the FAOSTAT Fisheries Data page, select “Fisheries” on the
left, then "Aquatic Plants" in the Processed Products field.
- In the left field, select "World+"
for the totaled harvest from all reporting countries. Select brown, green
and red seaweeds in the center field. (To select all three, push the CTRL
button as you click on each with the mouse).
- Designate "All Fishing Areas" on
the right, and "2001" in the far right.
- For output, select "table," set
X-axis as "years" and Y-axis as "countries", then
press "Submit to Database" to get the total. The units are
metric tons (MT).
· What was the total world harvest of brown seaweed in 2001? Of
green seaweed? Of red seaweed?
· Calculate the total world harvest of all three seaweed types and create a pie chart that
presents the 2001 harvest in a graphical way.
Next, let's focus
on the most significant harvests and where they come from. Which countries
harvested the most red seaweeds and brown seaweeds in 2001?
- Make a list of the top six countries in brown
seaweed production and in red seaweed production.
- Reset the left field for
"World>" for the harvest contributed by each reporting
country. Select a seaweed type, All Fishing Areas, and 2001. For the
"table" axes, set X as "countries" and Y as
"years." Submit.
For graphing
skills opportunities:
- With the data you gather, create a histogram
for each country with # metric tons on the Y axis. You could pin the
histogram columns on a world map to link the data with geographic
locations of seaweed sources.
- For side by side comparisons of output by the
top producing countries, you can combine the individual histograms onto a
single graph. Or, calculate the percentage of total world production
attributable to each country and create a pie chart.
Who Imports
Seaweeds?
Which countries
import the most seaweeds? Many countries import
seaweeds, including the United States. Use Trade Data
International's report to research who buys the most.
- Make a list of the top 5 seaweed-importing
countries in 2001.
- What was the value of seaweed imports into
all countries in 2001? (Use the average import price paid by the top importing
countries.)
- How much seaweed did the US buy in 2001? What
proportion of the world's seaweed market did this represent? From which
countries does the US buy seaweeds?
Sell Your Seaweed
Visit Ocean
Planet’s “There
Are Algae in Your House!” page, and use their list
of household foods containing seaweed products. Imagine that you would like to get into the seaweed business and culture
seaweed. Pick a type of seaweed that you might grow (red, green, or brown) and
determine which food companies might be interested in buying the corresponding
byproduct (carrageenans, beta carotene, or alginates)
from you. Design a marketing campaign to sell your seaweed byproduct.
Supply and Demand
Supply and demand
interactions drive the prices of commodities. Look at the Trade Data charts 10 & 13 of global seaweed imports and average import prices.
Describe the relationship between import quantity and price per ton. Think about what may affect supply of seaweed
products and what may affect demand for seaweed products. Also think about how this affects your
paycheck as a seaweed grower.
Seaweed products provide
just one example of how chemicals derived from marine organisms have become
increasingly important in our lives. The sea's biodiversity and extreme
environments continue to attract scientists as they search for new compounds,
organisms and biotechnology opportunities. The treasures we can extract from
the sea should also heighten our efforts to sustain healthy marine ecosystems.
