Additional Information and Advice
Table of Contents
- Procedures for Setting Advisories
- Information on Chemicals in Sportfish and Game
- Good Sanitary Practices - Bacteria, Viruses and Parasites in Fish
- Advice on Eating Raw or Partially Cooked Fish and Shellfish
- Bacteria in Clams, Oysters and Mussels
- Algal Toxins in Clams, Oysters, Mussels, Scallops, Snails, Crabs and Lobsters
- Blue-Green Algae Blooms
- Deformed or Abnormal Fish
- Botulism in Fish
Procedures for Setting Advisories
In New York State, these advisories are primarily based on information that NYS DEC gathers on contaminant levels in fish and game. NYS DEC collects fish samples each year from different waterbodies. In recent years, NYS DEC has annually collected approximately 2,000 fish from more than 50 locations/waters and analyzed these fish for various contaminants. Sampling focuses on waterbodies with known or suspected contamination, waterbodies susceptible to mercury contamination, popular fishing waters and waters where trends in fish contamination are being monitored. Also, testing focuses on those species that are most likely to be caught and eaten by sport anglers. NYS DEC also tests some game species (e.g., waterfowl, snapping turtles) that accumulate chemical contaminants.
Information on Chemicals in Sportfish and Game
Most of what we know about the potential health effects of these chemicals comes from high-dose laboratory animal studies or in people exposed by accidents or in the workplace. Chemicals that cause health effects in laboratory animals and people after high level exposures may also increase the risk of effects in people exposed to lower levels for long periods of time.
PCBs (polychlorinated biphenyls) are a mixture of man-made chemicals that were used in many commercial and electrical products until their manufacture was banned in the mid-1970s. PCBs are persistent in the environment and accumulate in the fat of fish and other animals. Thus, PCBs still remain a fish and game contaminant.
Studies of women and their children show a link between elevated levels of PCBs in their bodies and slight effects on their children's birth weight, short-term memory and learning ability. A study of older adults (49-86 years old) who ate fish containing PCBs suggests that higher PCB exposure is associated with decreased memory and learning. Other studies have suggested a link between increased PCB exposure and effects on the human reproductive system, including changes in sperm quality, time to pregnancy and menstrual cycles. These studies suggest that the effects were caused by PCBs, but other factors may have played a role too. Some PCBs have been shown to cause cancer in laboratory animals exposed to high levels of the chemical throughout their lifetime. Studies of workers exposed to PCBs raise concerns that these chemicals can cause cancer in people, but the information is not adequate to prove that this is the case.
Mercury is a metal that occurs naturally in the environment and can also get into the environment from human activity. Most of the mercury that accumulates in fish is an organic form called methylmercury. Fish that live longer and eat other fish tend to have more methylmercury than do smaller fish.
Methylmercury can cause effects on the nervous system. Exposure to methylmercury is more of a concern for children and unborn babies because their nervous systems are still developing. People who ate fish that contained large amounts of methylmercury had permanent damage to the brain, kidneys and fetus. Some research on populations that eat a large amount of fish finds that methylmercury can affect children's memory, attention and language development. Other research on a different population that also eats large amounts of fish has not found such effects.
Chlordane, DDT, Dieldrin and Mirex
Chlordane, DDT, dieldrin and mirex are all man-made organochlorine chemicals that were once used as insecticides. Mirex was also used as a flame retardant in a number of materials. Although these chemicals have been banned in the United States since the 1970s (with the exception that chlordane and dieldrin, which were allowed for termite control until the 1980s), they are very persistent in the environment and accumulate in the fat of fish and other animals. Thus, these chemicals can still be found as fish and game contaminants.
Chlordane, DDT, dieldrin and mirex can cause effects on the nervous system and the liver in laboratory animals. Chlordane, DDT and dieldrin have also caused effects on the nervous system of people. Some of these chemicals can also cause effects on the kidneys, the thyroid gland and on reproduction in animals and people. The levels of exposure that caused these effects are typically much higher than would likely occur from eating fish containing these chemicals. Chlordane, DDT, dieldrin and mirex also caused cancer in laboratory animals exposed to high levels over their lifetimes. Whether these chemicals cause cancer in people is not known.
Dioxins and Furans
Dioxins (polychlorinated dibenzo-p-dioxins or PCDDs) and furans (polychlorinated dibenzofurans or PCDFs) are two closely related families of chemicals. Some dioxins and furans are unwanted byproducts of manufacturing and also come from the smoke or ash of motor vehicles, municipal waste incinerators, wood fires and trash burning. Dioxins and furans are very persistent in the environment and accumulate in the fat of fish and other animals. Thus, these chemicals are fish contaminants.
Most of what we know about dioxins and furans come from one particular dioxin, but many of these chemicals are likely to cause similar health effects. Dioxins and furans have been associated with causing skin effects as well as changes in reproductive hormone levels and indicators of liver function in people. Weaker evidence suggests that these chemicals can also cause a number of other health effects in people. Such effects include an association between a mother's exposure and effects on her child's nervous system, hormone levels and immune system. Some dioxins have been shown to cause cancer in laboratory animals exposed to high levels of the chemicals throughout their lifetime. The available human studies provide strong evidence of an association between exposure to one dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) and cancer.
Cadmium is a naturally-occurring metal found in small amounts in soil and water. Cadmium is used in many industrial operations and in consumer products such as paints, plastics and batteries. Cadmium also occurs in foods (especially fruits, vegetables and cereals) and tobacco. Cadmium can also be found in fish and shellfish from some waters.
Cadmium accumulates in the body, mainly in the kidneys, with continued exposure. Some people with long-term cadmium exposure have had effects on their kidneys, bones and blood.
Lead can be found in fishing tackle (especially sinkers and jig heads).
Lead can cause health problems when it builds up in the body. Because the unborn baby and young child are at the greatest risk, it is particularly important for pregnant women, women of childbearing age and young children to minimize their lead exposures. Lead poisoning can slow a child's physical growth and mental development and can cause behavior and other nervous system problems, reproductive problems, kidney and liver damage, blindness and even death in both adults and children.
To reduce exposure to the lead in these products, you should:
- Keep all lead objects away from young children (young children often put their hands and objects in their mouth).
- Wash hands with soap and water after holding or using lead sinkers and jig heads.
- Never put lead sinkers in your mouth. This includes biting down on lead sinkers.
- Never eat, drink, or smoke immediately after handling lead sinkers, wash hands first.
- Take proper precautions when melting lead and pouring sinkers at home.
Consider non-lead alternatives. NYS DOH recommends that non-lead fishing sinkers and lures be used whenever possible. NYS DEC encourages anglers to use non-lead alternatives for sinkers and jig heads to reduce the risk of lead poisoning to birds. New York State law prohibits the sale of lead fishing sinkers (including "split shot") weighing one-half ounce or less. More information is provided on the NYS DEC website.
Good Sanitary Practices - Bacteria, Viruses and Parasites in Fish
Fish can be contaminated with bacteria, viruses or parasites that can cause illness. Avoid directly handling fish when you have cuts or open sores on your hands. You should harvest fish that act and look healthy, and follow good sanitary practices when preparing them. We recommend that you wear nitrile, rubber or plastic protective gloves while filleting or skinning. We also recommend that you remove intestines soon after harvest, don't eat intestines and avoid direct contact with intestinal contents. Hands, utensils and work surfaces should be washed before and after handling any raw food, including fish. Fish should be kept cool (with ice or refrigerated below 45°F or 7°C) until filleted and then should be refrigerated or frozen.
Advice on Eating Raw or Partially Cooked Fish and Shellfish
Foods of animal origin, such as pork, poultry, beef, dairy products, eggs, fish and shellfish, can be contaminated with bacteria, viruses or parasites that can cause illness. Persons at high risk (for example, those who are immunocompromised, suffer from liver disease or other chronic diseases) can be more susceptible to and more severely affected by these infectious diseases. This is why we recommend that all of these foods be thoroughly cooked before eating. Government agencies and the food industry strive to minimize contamination of raw animal foods and provide healthful food products.
Bacteria in Clams, Oysters and Mussels
NYS DEC routinely tests clam, oyster and mussel beds for bacteria. Based on these tests, an area may be closed to shellfish harvesting. Contact NYS DEC for more information.
Algal Toxins in Clams, Oysters, Mussels, Scallops, Snails, Crabs and Lobsters
Under certain environmental conditions, some types of marine algae will grow in abundance ("bloom") and produce saxitoxin, a dangerous neurotoxin. These events are generally temporary, occurring midspring to early summer in New York State waters. Because mussels, oysters, clams and scallops filter feed they can concentrate the saxitoxin in their body tissues. Carnivorous snails (conch, whelks and moon snails) can accumulate dangerous levels of the toxin as they feed on contaminated shellfish.
Eating foods contaminated with saxitoxin can cause paralytic shellfish poisoning (PSP), which affects the nervous system and in severe cases can lead to paralysis, respiratory failure and death. Saxitoxin cannot be removed through cooking. If consumption of saxitoxin is suspected, seek medical attention immediately.
NYS DEC monitors shellfish for saxitoxin, and temporarily closes harvest in areas with elevated levels of saxitoxin. Do not harvest or eat clams, oysters, mussels, scallops or carnivorous snails (conch, whelks, and moon snails) from areas closed to shellfish harvest due to saxitoxin.
NYS DOH advises that people not eat the soft green material (mustard, tomalley, liver or hepatopancreas) found in the body section of crabs and lobsters from any waters because cadmium, PCBs and other contaminants as well as toxins produced by some marine algae concentrate there. Because contaminants may be transferred to cooking liquid, people should also discard crab or lobster cooking liquid.
Check the NYS DEC website for information on shellfish harvest and for information on saxitoxin and other marine toxins. You can also call NYS DEC at (631) 444-0475 for information on shellfish regulations, including areas in which clam, oyster and mussel collection are permitted and at (631) 444-0480 for the latest information on emergency closures.
Blue-Green Algae Blooms
Blue-green algae are microscopic organisms naturally present in lakes and streams. They can become very abundant in warm, shallow, undisturbed surface water, forming "blooms" (often called algal blooms) that discolor the water or form scums on the water surface. Some blue-green algae produce toxins that could pose a health risk to people, pets and livestock when they are exposed to them in large enough quantities. Therefore, you should avoid all water contact (including swimming, wading and fishing) in areas where you can see algal blooms, and don't eat fish caught in areas with visible algal blooms. Rinse exposed skin with clean water if you contact algal blooms. For more information on algal blooms go to NYS DEC's website and for more information on potential health effects go to the NYS DOH website.
Deformed or Abnormal Fish
The health implications of eating deformed or abnormal fish are unknown. Any obviously diseased fish (marked by tumors, lesions or other abnormal condition of the fish skin, meat or internal organs) should be discarded.
Botulism in Fish
In recent years, large numbers of some species of Lake Erie fish and waterfowl have been found dead, sick and dying, many of them as a result of botulism poisoning. The botulism poison is produced by Clostridium botulinum, a bacterium that is common in the environment and can produce harmful levels of botulism poison under some conditions. This poison has been found in some of the affected fish and waterfowl. The botulism poison can cause illness and death if eaten by humans or animals. Cooking may not destroy the botulism poison. This problem may also occur in other waters, and we don't know whether all or only some fish and waterfowl species can be affected. NYS DEC continues to monitor and investigate this problem.
No human cases of botulism poisoning have been linked to these events. However, as a precaution, do not eat any fish or game if they are found dead or dying, act abnormally or seem sick. If you must handle dead or dying fish, birds or other animals, cover your hands with disposable nitrile, rubber or plastic protective gloves or a plastic bag.