Aquaculture
AQUACULTURE



Section 1:

For thousands of years we've grown food on the land. We haven't simply collected what grew there naturally, we've planted the crops that we wanted to grow, tended them, improved them, and let them sustain us. We've selectively bred larger and "better" animals. Larger cows, meatier chickens, faster growing and healthier animals are our goals. The strange thing is, as far as the ocean is concerned, we essentially still only collect that which the sea provides. It makes a lot of sense to me to apply our techniques used in agriculture (growing food on land) to Aquaculture (growing food in the water).

Seventy one percent of the Earth's surface is covered by ocean water. Much more of this water could be producing food for us in an intensive, controlled, safe and sustaining way.

The first step may be to change our perceptions of what is good to eat. The "trash fish" of today may be the preferred food items of tomorrow. This has certainly been the case many times in the past. Not so long ago, in Maine, lobsters were collected by the basketful from tide pools along the shore and dumped into home gardens as cheap fertilizer! Today you and I, and lots of tourists pay up to eight or nine dollars a pound for this fertilizer! The great thing about Aquaculture is that you can apply the techniques to many traditionally eaten species as well. Scientists have been able to produce oysters, mussels, scallops, salmon, sea bass, even seaweed species for the consumer. Aquaculture can be used to improve the species, or simply to assure a constant and plentiful supply. Some forms of Aquaculture have been compared to the well established process of stocking certain fish species in freshwater locations to assure an ample supply for an ever increasingly demanding public. Aquaculture can be a valuable business proposition too. Even though we Mainers don't think much of the lowly sea urchin, and certainly wouldn't be tempted to sit down to a plate of sea urchin roe instead of our fish and chips, not everyone in the world feels the same way. Several successful businesses in Maine are now collecting and selling the urchins to an eager Japanese market. In the past few years we've seen companies grow seaweed for export. There's even an organization growing seaweed for biomedical research. Imagine, the next big discovery in the fight against certain diseases may well come from the ocean in Maine's own backyard! 

Maine has the ideal environment in which to practice Aquaculture. Our 3,000+ miles of sheltered coastline are ripe for aquacultural development. In his 1995 Inaugural Speech, Maine's Governor Angus King stated that Aquaculture is one of Maine's great emerging industries. If we were to develop an industry similar in scope to that of Norway, it is estimated that the industry would employ some 9,000 workers! Aquaculture could easily become the largest industry, and largest employer, in the State!


Section 2:

Aquaculture Techniques

OYSTER FARMING: The successful culture of oysters necessitates a complete understanding of the oyster's life cycle. This is pretty much true though no matter what you want to raise or grow. An oysters' life cycle begins with male and female organisms producing a fertilized egg. When this egg hatches it becomes a type of free-swimming larva known as a TROCHOPHORE LARVA. Only in this larval stage is the oyster at all a mobile creature. When conditions are right, the oyster sets. When an oyster sets, it builds a shell and settles onto the bottom, usually on other oyster shells. From this point on the oyster is strictly a bottom dweller, incapable of any movement. It filters the water for food and pretty much remains this way for the rest of its life.

It is possible to collect the tiny oysters just after they set. At this time in their lives, they are referred to as SEED OYSTERS.

The culture of oysters is carried out in two predominant ways.

Bottom Culture of Oysters- This is perhaps the simplest, though not always the most efficient method of growing an oyster. The Aquaculturist places crushed shells on the bottom of the ocean. This is necessary, as oysters will only live and grow on beds such as this, or at the very least, on some other source of Calcium Bicarbonate, the substance of which shells are composed. The naturally occurring larvae will "set" upon these shells and the Aquaculturist is assured of a harvest when the stocks mature. A variation of this method involves actually placing the "seed oysters" on the beds of shells in the ocean. This could be equated to a farmer preparing the field and then actually planting seeds in the field. It is so simple that it makes perfect sense. A lot of the aquaculture techniques that we will explore are examples of this type of "common sense". The benefits of this method are that the Aquaculturist mimics what happens in nature, except that he or she gets to have some control over the location of the stock. This method is relatively inexpensive and requires little equipment. Oyster loss can be high however, from predators, parasites and competition. Oysters raised in this way take a little longer to reach market size, sometimes twice as long as oysters raised in using the suspended tray method. Oysters raised on the bottom may have thicker shells and a lower quality meat product than the tray cultured variety.

Raising Oysters in Suspension- Another method of oyster aquaculture involves raising the oysters from seed to adult in suspended screens or trays. The trays are often stacked upon one another and suspended from buoys on the water's surface. The seed oysters are placed in these trays. Periodically, the Aquaculturist cleans and scrubs each tray. The advantages of this method are numerous. The oysters are protected from bottom-dwelling parasites and ocean predators. Since the trays are suspended higher in the water column, they are exposed to more surface currents which carry food, oxygen and nutrients to the oysters. The end result is that the oysters grow faster than they normally would, reaching market size in a fraction of the time usually necessary. The oyster meat will generally be a higher quality product, grit and parasite-free. Of course, all of these benefits come with a price. The Aquaculturist must buy and maintain the equipment, pay for labor and transportation costs, and supply the seed. The suspended trays can be damaged by vandals and storms, causing great monetary losses. Additionally, the tray-raised oysters are at-risk during Maine's cold winter temperatures. (and we've certainly got plenty of cold temperatures during one of our winters!)

Japanese Pearl Oysters-

All oysters, and most shellfish, produce "pearls". A pearl is simply a way for the oyster to neutralize something that is irritating it within its shell. These irritants include parasites and tiny pieces of sand and rock. The irritant is covered up with layer upon layer of shell, the same type of shell that lines the inside of the oyster's shell. A pearl grows larger as time passes. Unfortunately, most pearls are not very valuable at all. One oyster produces jewelry-quality pearls, and is being successfully culture in Japan. The oysters are raised in a tray culture, and early in their lives, they are temporarily removed from the trays so that tiny round objects can be place within their shells. When the oysters are replaced in the trays, they start to build up layer upon layer of pearl coating around the offensive object. In about two years, the pearls are large enough for harvest. A single strand of perfect, matched pearls can cost thousands of dollars!!

Mussel Farming: The Aquaculturist's techniques used to raise mussels are quite similar to those used for oysters. Certainly it is quite possible, though expensive, to raise the mussels in suspended trays. Mussels are also being raised in suspended bags made of mesh. Another popular method is called Longlining.

The longline method of mussel aquaculture:

Mussels produce a BYSSAL THREAD. Mussels use these tough, threadlike strands to anchor themselves in the turbulent Balanoid zone. This byssal thread can attach to pretty much anything; rocks, weeds, docks, etc. Aquaculturists have discovered that if you suspend a long rope to a float in the water, mussels will attach to it. These longlines have the advantage of raising the growing mussels up off from the bottom, garnering all of the benefits accrued by the tray culture of oysters. Mussels raised in suspension grow to maturity in only about 2 years, rather than the 7 years that it takes in the wild. A larger percentage of cultured mussels survive to market size as well, because of the protection from parasites and predators, which mostly all live on the ocean floor. All mussels will develop pearls after about two years living on the ocean bottom. The presence of pearls decreases the value, and edibility of mussel meat. Unlike the pearls from certain oysters, mussel pearls have no value. Since cultured mussels are all only about two years old or younger, they rarely contain pearls. Cultured mussels are less affected by parasites and have better quality of meat overall than do bottom-raised mussels. Cultured mussels also tend to have thinner shells, meaning that there is more mussel meat per pound of mussels sold, making them a better value for the consumer. The last time I purchased mussels, wild mussels sold for less than a dollar a pound, while cultured, or farm-raised mussels were selling for about two dollars a pound. Even though cultured, or farm-raised mussels are more expensive, I greatly prefer them to the non-farm-raised variety. The absence of all grit and pearls, in my opinion, justifies the difference in price.


Section 3:

Aquaculture of Atlantic Salmon

Salmon are an interesting species, born in freshwater, they travel downstream to the ocean where they spend the first two or three years of their adult lives, then they return to the same stream in which they were born to spawn, (lay their eggs), and eventually, die. Salmon are also a very valuable and much sought after species by commercial and game fishermen. Like many of our valued species, population numbers have been steadily decreasing lately. Mankind has an often devastating effect on the environment of the salmon. When we build dams, divert river flows or develop land near rivers and streams, we are often destroying the salmon's habitat. At the very least, we can make it difficult or even impossible for the salmon to reach its goal. (Try swimming upstream over a dam sometime if you don't believe me!). Because of these problems, and the ever-increasing demand for quality salmon by consumers, it makes more sense than ever to explore the methods by which salmon can be raised using the techniques of Aquaulture. Even since I've started putting together this website, several aquaculture operations have begun in Maine, with more apparently on the way.

Two salmon aquaculture techniques enjoy widespread use today.

Salmon Farming: This process works much as you would suspect. Young salmon are raised from an egg to adulthood in a hatchery setting. Advantages of this method are that you can retain a high degree of control over the fish. You can care for them, and insure their continued healthy and productivity. You can practice the science of genetic selection, to actually improve the species. The fish are yours, you own them. Major disadvantages include the various costs associated with this method. Electricity to run the hatchery, medical costs, food costs, upkeep of the hatchery facility as well as hired labor costs to keep everything running smoothly. Not to mention the fact that you need money to buy the land and the hatchery facility in the first place!

Salmon Ranching: This process takes advantage of the salmon's natural homing ability. The fertilized eggs are raised until they are small salmon, about six inches long, sometimes called "fry", or "fingerlings". The salmon fry are released into the ocean to seek their fates. Many will die due to disease and predators, as well as fishing pressure from both commercial and sport fishermen. Some small percentage of the salmon manage to survive to maturity and in time (2-3 years) will return to the very stream (and hatchery) where they were born. At this point, the salmon are collected and brought to market. The benefits of this type of system all revolve around the great cost savings that you can gain by not having to keep a hatchery running. Your initial monetary outlay can be fairly small, and even though only a small percentage of the fish survive, if you start with large enough quantities of fry, the fish that return can more than pay for the bills piled up during their maturation process. The major drawback is your loss of control over these fish. You are powerless to protect them from predation or disease, devastation by commercial or sport fishermen, or just plain bad luck. The ocean can be a harsh environment, and those little fish look mighty tasty to a wide variety of the ocean's inhabitants. The entire concept of Salmon Ranching really hinges on the fish finding their way back home, and the percentage of fish who manage to carry out that daunting task.

Both Salmon Ranching and Salmon Farming are quite successful operations in the Pacific Northwest and Alaska. Maine has a promising industry in this area, one that is becoming more widespread in our region each year. A short trip to the top of Cadillac Mountain can confirm how many Aquaculture operations are going on right under our noses. The lovely town of Eastport, Maine has been another great example of how the culture of Salmon can revitalize the economy of an area. Connor's Aquaculture, based in Eastport has a large, multi-million dollar operation. What a great way to breathe life into a sagging economy. Other countries such as Norway and Scotland also practice this method of Aquaculture. But the Maine Atlantic Salmon tastes best! So those are the ones you should buy!


Section 4:

Intensive Aquaculture Techniques

The term "Intensive Aquaculture" refers to what is the next logical step in the Aquaculture industry. It involves maximizing yield and carrying out as efficient an operation as is possible. Advantages include an increased cost effectiveness and species productivity.

Monoculture- This term refers to the growing of one species only in a given area, much like our fields of wheat and corn in America. by carefully supporting the environment, you can reap a much more productive harvest. Many times more productive than in the wild. In the southern parts of the United States, some farmers have given up raising cotton, wheat or other traditional crops and have flooded their fields. These flooded fields become the home to large populations of cultured catfish and prawn.

Polyculture- This term refers to growing more than one species, each with different needs, in the same area. The process involves having an in-depth understanding of the needs of each species that you want to put in the area. The Chinese, longtime participants in the science of Aquaculture (but not human rights), have developed what has become a world renowned model of polyculture, the Carp Pond. In these small ponds, many fish populations, each with different food and habitat needs, are raised in the same area. The species do not compete with each other for the limited food or space, since they all eat different things and live at different levels within the pond. These ponds can be five or more times more productive than a pond of a similar size in the wild. These ponds are a shining example of how to maximize space, food and labor efficiency.


Section  5:

Future Trends

I find the science of Aquaculture particularly enjoyable because we are still in the process of discovering its true potential. New ideas, experiments and successes happen every day. Living in Maine, a place which could become a leader in the field, is especially enjoyable. These are lots of new ideas out there, and a section titled "Future Trends" will probably be outdated before this site hits the Internet. Some promising looking areas to monitor in Maine are described below.

Lobster Seeding: In Maine, and around the world, the Maine Lobster is well know and a prize most highly sought after. Unfortunately, lobsters are notoriously difficult to raise in captivity. Today, there might not be much interest in the culture of lobsters, since each year for the past decade or so, Maine fishermen have brought ashore more lobsters each year than the last. This worries me. It seem logical that we can't go on catching more and more members of a population without messing the system up somehow. We've certainly made similar mistakes with other species, the Cod, the Haddock, Salmon, lots of trees...pretty much everything but black flies! The point is that it makes sense to me to explore the possibilities of raising Lobsters using Aquaculture. A successful industry in this area could relieve some of the pressure on the native populations. Maybe we could use genetic selection to actually improve the lobsters that we raise. Experiments currently underway are attempting to create a habitat suitable for lobsters, both in the wild and in a hatchery setting. The idea is that if the habitat is there, the lobster population will expand to utilize it. A second experiment involves "seeding" lobsters. That is, raise young lobsters in a hatchery setting and then transplant them into your prepared areas when they are able to survive on their own. Results are not conclusive at this time as to the practicality of these methods, but certainly a cheap, plentiful, sustainable supply of aquacultured lobsters is an attractive prospect.

Nori- Nori is a protein rich seaweed. You may see it as the crispy green coating wrapped around sushi and the like. It can be used as a protein source and food supplement. Nori is also important in the biotechnology industry, also gaining footholds in Maine. You can follow the links below to learn more about this most interesting aspect of aquaculture.

The time to explore these ideas with vigor is upon us. The future of this wonderful world literally depends upon finding ways to provide enough food for all of its people. Aquaculture has got to be a part of that solution. Maine, and its great people, have the opportunity to lead in the search for that solution. Long ago, in another time of strife and uncertainty the people of this land had a slogan "As goes Maine, so goes the Nation", perhaps it is time to prove that those words can still be true today.