Eating salmon may be good for you, but catching them for a living could be hazardous to your health.
Commercial salmon fishermen in Alaska suffer from hearing loss at more than five times the national rate and also face higher rates of other serious health problems, according to a new study led by a researcher in the UW Department of Environmental & Occupational Health Sciences (DEOHS) and others from the School of Public Health.
"Commercial gillnet fishing is difficult and dangerous work," said senior author Debra Cherry, a DEOHS adjunct associate professor. "Gillnetting has unique risks compared to other types of fishing, especially for upper extremity injury. Fishermen have to set out and reel in the long net and pick off each salmon."
Catching Copper River salmon
The study, published in the Journal of Agromedicine, surveyed and assessed a group of gillnet fishermen along Alaska's Copper River who catch and sell what some call the world's finest salmon. The study was conducted in partnership with Alaska Sea Grant.
About 80 percent of fishermen who completed a hearing test had a pattern suggestive of noise-induced hearing loss, compared with the 15 percent norm for Americans. They also had significantly higher rates of upper extremity injuries, such as carpal tunnel syndrome and tendonitis, and were at increased risk for sleep apnea.
Researchers found evidence of upper extremity disorders of the hand, wrist, elbow and shoulder combined in 70 percent of physical exam participants. Rotator cuff tendonitis, in particular, affected 40 percent of participants. The national norm is 8 percent to 14 percent.
"The fleet is self-employed. There is no corporate entity that protects them," Cherry said. "We need to be mindful of the risk, provide guidance to these fishermen and advocate for the promotion of the least risky work practices."
Engine noise may be a factor
The start of salmon fishing season on the famed Copper River in Cordova, Alaska, is met every May with fanfare by people in the Pacific Northwest. The wild salmon is prized for its high fat content and rich flavor.
Some 550 fishing vessels are licensed to use drift gillnets to catch salmon. The nets are hung vertically in the water, up to 150 fathoms in length, drifting with the tide and current.
Cherry also points out the small size of typical boats used for gillnetting, which often have crews of only one to three people. "Fishermen are at risk of noise exposure because they're working so close to the boat's engine. It's just right there," she said. "However, many of the fishermen also had loud hobbies, such as hunting and snowmobiling, so we can't say for sure that their hearing loss was tied to their job."
The potentially high prevalence of obstructive sleep apnea is also concerning, say the authors. Less sleep combined with poor quality sleep may exacerbate fatigue during the fishing season.
Measuring fishermen’s health
Researchers surveyed fishermen before and halfway through the 2015 fishing season, which generally lasts four months. Study co-author Torie Baker, a marine advisory agent at Alaska Sea Grant, and members of Cordova District Fishermen United invited 600 fishermen to answer questions about medical and work history, sleep habits, alcohol and tobacco use, mental health, physical fitness and noise exposure.
Twenty fishermen underwent a complete physical exam, where their hearing and aerobic fitness were tested. Some were also outfitted with Fitbits to track activity and sleep habits.
Nearly 80 percent of the fishermen considered themselves healthy and had evidence of above-average fitness before fishing season began. Compared to the general Alaskan population, study participants reported less tobacco use, more regular doctors' visits for health maintenance and higher rates of health insurance.
Seventy percent of fishermen in the study were overweight or obese, which is about average for the population of Alaska, and participants reported less aerobic exercise during the fishing season, likely due to cramped space on fishing vessels.
Busy work schedules and excessive fatigue were also reported. Fishing periods usually lasted 24 to 48 hours, with little chance of sleep and unpredictable bursts of heavy activity.
Sixty-six fishermen took part in the preseason online survey, and 38 responded to the midseason survey. Most fishermen in the study were white males, at an average age of 49 with 27 years of commercial fishing experience.
The U.S. National Institute for Occupational Safety and Health funded the study through the Pacific Northwest Agricultural Safety and Health Center within DEOHS. Lead author Carly Eckert is a doctoral student in the UW Department of Epidemiology.