Aquaculture, like any other industry, has its costs and benefits, as well as its proponents and opponents. Students will discuss some of the pros and cons related to aquaculture. As a class, the students will discuss the hypothetical case studies provided. In cooperative learning groups, students will engage in an aquaculture debate in the style of a town meeting.
2 class session
This activity supports the following National Academy of Sciences science education standards.
This activity supports the following National Council for the Social Studies standards.
Aquaculture - the production of aquatic organisms for human use-is an increasingly important source of seafood. Many believe that it can help fill the gap between the growing demand for seafood and what can be caught in the wild. It can also provide jobs and rejuvenate the seafood processing industry in some places.
Aquaculture exists in almost every country in the world, but the US produces relatively little. Even though national policy is aimed at encouraging aquaculture initiatives, there are still many barriers to starting new aquaculture ventures including:
Starting a new aquaculture venture is expensive, it requires a large initial capital investment, and it may be quite some time before entrepreneurs begin to see a profit. Banks may be skeptical about loaning large sums of money to small aquaculture entrepreneurs. As a result, new aquaculture enterprises often favor large businesses over smaller, community operations.
Not every body of water can serve as a site for an aquaculture facility and many species are farmed inland in human-made ponds or raceways. Very specific requirements must be met. For example, to raise Pacific White shrimp, pond water must remain near 75-85 degrees for three to four months while the shrimp grow to full size. For salmon or other finfish grown in net-pens in the ocean, you must have very strong tides to disperse the wasted produced from the finfish or you risk polluting the surrounding waters. For oysters, mussels and other mollusks, you must have nutrient-rich water. Culturing mollusks and aquatic plants usually has minimal negative environmental consequences.
Aquaculture operations in the ocean and on the coast are always at the mercy of Mother Nature. Storms and other oceanographic and meteorological conditions can wreak havoc on one's fish, mollusk, or shrimp farm. A specific threat related to farmed bivalves is a tiny organism called fecal coliform bacteria which can enter the water via sewage, particularly during times of flooding. Because these bacteria can contaminate the bivalves and threaten the health of consumers, mollusks must be grown in clean waters. In spite of all these hazards, excellent environments for aquaculture operations across the U.S. do exist.
Aquaculture production of some species and in some areas is being done in a way that minimizes environmental impact. Several conservation organizations such as Monterey Bay Aquarium, Environmental Defense, and Blue Ocean Institute publish seafood cards that rate farmed catfish and tilapia, for example, “green” (the best designation). But many people are concerned that some forms of aquaculture can create more problems than they alleviate. On fish farms, species such as shrimp and salmon are fed high-protein pellets which include high percentages of fishmeal and fish oil made from small wild fish such as anchovies. There is a range of scientific opinion about exact conversion ratios, but fisheries experts agree that raising carnivorous species currently consumes more fish than it produces, putting pressure on wild fish populations.
To make way for modern aquaculture operations, farm fields may be flooded for catfish ponds, shrimp farms may be adjacent to sensitive coastal forests, and waters in coastal areas may be fenced to raise “crops” of salmon, mollusks, and seaweed.
Dead fish, uneaten food, and excrement wash directly into waterways from many modern aquaculture operations. And the antibiotics, vaccines, and chemicals that many farmers use to fight disease get flushed away, too, with unknown effects on wild fish and their habitat. The U.S. Environmental Protection Agency recently established national standards to control the effluent from aquaculture operations.
Fish farms often raise fish that aren't native to the area. Farmed fish are usually stocked in cages when disease-free. They often catch diseases that are naturally occurring in the water and on wild fish, and then amplify the disease or parasite due to high stocking densities. Now the disease can become a much larger threat to wild fish that swim by the net-pens. When farmed fish escape, they can become established in the wild, and compete with or prey on native fish. Up to 50% of salmon caught in certain rivers in Norway are of farmed origin, and on average they estimate that 1/4 of all salmon in the wild are of farmed origin (not just escapees, but also offspring of escapees).
Among the biggest barriers to starting new aquaculture ventures in the U.S. is a lack of appropriate areas for mariculture or culture of species along the coast combined with local public opposition. Although there are many people who support and encourage a growing aquaculture industry, there are others who oppose growth in this industry if it does not appear sustainable.
A long-term goal of the aquaculture industry and government proponents is to help offset the annual $8 billion seafood trade deficit (as of 2005). For example, the US is the largest importer of farmed shrimp, and currently, over 70% of the seafood that Americans consume is imported, and at least 40% of our seafood imports are aquaculture products. Success with aquaculture in the United States requires high rate and high yield production systems that are both environmentally and economically sustainable and yield a high quality product.
Before the Activity
Prior to class, have the students read the Two Florida Communities handout.
In the aquaculture debate, groups of students will role play a position on aquaculture and defend it in a town meeting. Select about six roles from this list, or create roles appropriate to your community: commercial fisherperson, tourist bureau representative, homeowner, vacationer, local/state politician, small-scale aquaculture entrepreneur (local), large-scale aquaculture entrepreneur (international), scientist, or conservation group representative.
Before the debate, stress the professionalism and decorum which ought to take place in a town meeting. Establish a set of guidelines based on mutual respect so that the debate does not degenerate into a shouting match. You may need to stress that the point of a debate is to adopt the position of the group and defend that position. The position may or may not reflect the students' own opinions. Therefore, students ought not to feel personally attacked and have the advantage of learning how to argue positions other than their own. Students should gain an understanding of the complexity of community issues.
Break the class up into as many groups as there are roles. Assign (or let the groups choose) a different role for each cooperative learning group. You may want to provide a “blurb” describing each group's general position on aquaculture. However, be careful not to pigeonhole groups into black and white categories. There are advantages to letting the students struggle with defining the roles of these groups themselves, rather than providing them with a predetermined script. Encourage groups to approach this as a real-life scenario.
Give students time (20-30 minutes) to prepare their case. They can use the Two Florida Communities handout and the Aquaculture Pros and Cons as reference materials to help build their arguments. Case statements can include stipulations such as: “I support aquaculture in the community if x, y, and z are included.”
Ask students to write an essay describing their personal opinion regarding the class vote and explain their reasoning.
Adapted with permission from “To Culture or Not to Culture: The Controversy Continues” in the Maine Aquaculture Curriculum Guide by the Maine Aquaculture Innovation Center
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