What is the purpose of the volunteer sampling program for mercury in fish?
The purpose of the volunteer fish sampling program is to better characterize the levels of mercury that are accumulating in freshwater fish that are commonly caught and consumed from New Hampshire surface waters. Through the use of volunteers, fish can be collected and analyzed from surface waters throughout the state.
The program consists of three basic steps: volunteers collect fish and submit them to the NHDES Limnology Center; NHDES processes the fish (records location, length & weight and removes ear bones for aging) and submits them to the Public Health Laboratory; and the Public Health lab analyzes a fillet of the fish for total mercury.
Who can submit fish?
Anyone can submit fish that was caught in the fresh waters of New Hampshire.
Note: All fish should be collected in a manner that is consistent with acceptable methods, laws and rules as stated in the NH Freshwater Fishing Digest, published by the NH Fish and Game Department.
What equipment is needed?
- Ziplock freezer bags
- Ice chest
- Ruler or tape measure (optional)
What is the collection protocol:
- Scrub ice chest with detergent and rinse well
- Wash hands prior to leaving for field
- Avoid contact of the fish to any unclean or painted surfaces or to metal
- Measure fish length (optional)
- Place fish in ziplock freezer bag
- Seal bag and place in an ice-filled cooler
What information is needed?
- Name of water body and town
- Species of fish (DES will help if unknown)
- Date of collection
- Fish length (optional)
Can I freeze the fish?
The preference is to place the fish on ice and submit to NHDES within 24 hours of collection. This is because there will be some loss of weight from dehydration from freezing. However, the fish may be frozen if a 24-hour delivery is not possible. If frozen, the fish should be frozen flat (not curled) in the ziplock bag, length measured where possible, and submitted within 7 days of collection.
When should fish be submitted?
Fish can be collected and submitted at any time during the year.
What size and species of fish can be submitted?
All species and sizes (within legal limits) of fish can be submitted, but sizes and species of fish commonly caught and consumed are preferred because of human health effects. Larger fish tend to accumulate higher levels of mercury than smaller fish, and warmwater predatory fish tend to have higher mercury levels than coldwater or plankton-eating fish.