Top 10 Problems
Offshore fish farming, also known as open ocean aquaculture, involves giant cages located about 30 feet under water anywhere from three to 200 miles off the coast.
Here are 10 reasons why this is so problematic.
Open water aquaculture facilities could cause conflict of interest. Areas of current significant competing economic use or public value must be eliminated for consideration for open ocean aquaculture. These areas include 1) fishing grounds and routes to those fishing grounds; 2) vessel traffic lanes; 3) military sites and areas of concern regarding national security; 4) marine reserves and otherwise protected areas; and, 5) areas of significant multiple use.
Offshore aquaculture of finfish uses cages or pens. These containers, even if well engineered and built, will allow some fish escapes into the open ocean, due to various complications like severe weather, equipment failure or human error. In the case of net pens, predators may tear the enclosures. Escapement can affect native populations through disease and dilution of locally adaptive gene complexes, disrupt natural ecosystems and jeopardize the recovery of depleted or endangered species. Consequences could be widespread and devastating.
Growing Exotic / Mutated Species
Several problems are associated with aquaculture production of non-native species. While the use of local species in aquaculture presents less harmful impacts should escapement occur, often when cultured species reproduce in captivity, they or their offspring are different behaviorally or even genetically. These ‚new” species may invade local areas, breed with or overtake natural populations, through escapement, causing widespread environmental concerns.
Growing Genetically Modified /Transgenic Organisms (GMOs)
Farm raised fish are bred for profit, thus, those that have certain marketable traits are the most desirable. Selecting and only breeding fish with advantageous characteristics (e.g. largest and fastest growers) is one means to alter genetic composition over time. In some instances, direct genetic manipulation occurs in a lab, to change, for example, appearance and breeding abilities. In either of these circumstances, the outcome produces a genetically different fish than those found in the wild. Similar to problems associated with culture of exotic and mutated species, proposed farming of GMOs raises concerns that through escapement, the constitution of the ecosystem may be altered, not to mention unknown health concerns to the consumer.
Use of the U.S. EEZ for aquaculture requires construction of appropriate facilities and in some areas could include severe habitat impacts. Dredging, drilling and other sediment and bottom habitat disturbances, can cause displacement of ocean wildlife and other potentially significant ecological changes.
Cultured species are fed wild species. This is an inefficient use of wild fish. There are particular concerns that aquaculture operations may increasingly rely on natural food sources, such as krill, squid and other small coastal pelagic fish. These lower trophic level species are a crucial part of the marine ecosystem, serving as prey for marine mammals, birds and fish. Many commercially and recreationally important fish species depend directly on the availability and abundance of such prey species for their survival and recovery. Wild fish populations can only recover if the ecosystem upon which they depend is intact.
Mitigation Plans for Hazards
A number of threats to wildlife and the environment can come from open water aquaculture. A facility should be prepared to address emergency situations, especially where immediate containment or clean-up are necessary. Permits should only be provided once the applicant develops and submits a plan to mitigate potential harms due to unexpected circumstances, including escapement of fish, chemical pollution, illness and others.
Human Health Concerns
Studies indicate that farm-raised fish contain higher levels of chemical pollutants than wild fish, including PCBs, which are known carcinogens. This is due to higher concentrations in the fish feed. Antibiotics are also a problem with farm-raised fish, effecting consumers directly as well as by developing super strains of bacteria that are resistant to antibiotics, making diseases less treatable, and perpetuates the cycle of increased antibiotic use.
Unexpected Environmental Harm and Abandoned/Bankrupt Facilities
Open-ocean aquaculture depends on various factors, including weather, currents, disease control and human precision. Some of these are not controllable. It is possible that a facility is damaged by any number of unplanned events, causing a major escape or significant chemical pollution. Remedying such situations requires significant monetary resources that might not be available from the company at the time of the occurrence.
Water pollution concerns include the following:
- excess food;
- cage materials; and,
- antibiotics/other cleaning/algal growth prohibiting chemicals.
Water flowing out of an aquaculture facility can carry excessive nutrients, particulates, bacteria, other diseased organisms and polluting chemicals. These may harm surrounding habitats, cause algal blooms, poison ocean wildlife and other severe disturbances. Feed and fecal matter from aquaculture facilities can deplete the dissolved oxygen concentrations within and around the site. Since different fish have varying tolerances to dissolved oxygen levels, the wastewater being discharged from an aquaculture operation may have large impacts outside the facility long before a problem is detected within. Anti-fouling agents used to keep cages/pens clean are highly toxic. For example, the common anti-fouling agent butyltin (specifically tributyltin) has been linked to reproductive problems in gastropod mollusks (i.e. whelks and abalone) and is suspected to cause immune suppression in marine mammals including dolphins, seals and sea otters.