Many of the dangers associated with fishing are well-known. Trips, slips and falls, getting caught in machinery and falling overboard are all documented – but what about the occupational health impacts that are often associated with the profession?
As the FISH Safety Foundation began searching for targeted information in this area, we came to a frustrating conclusion – while some of the negative health outcomes associated with fishing are discussed, the scope of the problem is hard to quantify due to the lack of research in the area. Conditions such as musculoskeletal disorders, respiratory concerns, mental health disorders and some cancers have been linked to the occupation, but the details of these relationships need further attention.
By reviewing the information that does exist (and remains relevant) the Foundation has created an overview of the health conditions that warrant further discussion within this group. To ensure relevance for all fishing communities, this will be undertaken in two separate reports focusing first on occupational health in the developed world, followed by an overview of occupational health in developing countries.
Occupational Health in the Developed World
Compared to land-based populations, the health of marine populations remains poor  and the need for further research has been highlighted in multiple studies. Evidence suggests fishermen have a higher prevalence of occupational ill health than other occupational groups as well as the general population. 
Fitness for Duty examinations have long been required for seafarers to ensure their health is compatible with work at sea, yet these obligations often don’t apply to many fishermen despite the dangers of their work. The Work in Fishing Convention C.188  has established a requirement for medical assessment for fishers working on all vessels unless the competent authority has granted an exemption. Unfortunately, due to the slow uptake of C188, most fishermen are not yet protected by this guideline.
Despite some of the risks of fishing being universal, the size of the vessel, crew size and roles onboard can all influence injury and illness rates. Previous research into commercial fishing has been largely focused on large scale operations. Small scale commercial fishermen comprise a significant proportion of the workforce and injury burden but continue to be under-researched.  Those working on small to medium sized vessels will likely perform more manual work, such as throwing and hauling lines, and catch treatment. Accommodation spaces on these smaller vessels may be limited with less protection from vibration and noise, all of which are likely to generate high physical and psychosocial demands on fishermen. Smaller crew sizes can also increase risks, with fishermen performing multiple tasks with tighter shift rotations, increasing levels of fatigue.
|Health problems within the fishing industry|
|Musculoskeletal conditions||Respiratory conditions|
|Gastro intestinal disorders||Dermatological complaints|
|Mental Health / Neurological conditions||Cancers|
|Ocular concerns||Hearing loss / Tinnitus|
|Dental conditions||Heart / Circulatory disease|
It is critical to understand the interrelated effects of work on health, and of health on work. Just as risks from the job can impact on your health, the state of your health can impact on your work. One is not separate from the other, and there are often multiple contributing factors at play at any given time.
Not only do the specific duties and exposures associated with the industry contribute to ill health, but the working conditions and culture in fishing influence behaviours which increase risk factors for common chronic diseases.
The resulting health outcomes can be considered in two different ways – Occupational Lifestyle Impacts which have been influenced by lifestyle or behavioural aspects associated with commercial fishing and Occupational Exposure Impacts which have been influenced by the working conditions and duties of that position. Some conditions, such as cancers, can be classified differently, or even jointly, depending on the type and location of the disease.
- Occupational Lifestyle Impacts
Fishermen are often seen to exhibit unhealthy behaviours in their day to day lives, such as high levels of smoking, poor stress management, inadequate quality and quantity of sleep, and poor nutritional habits.
Sleep and Fatigue
Fatigue is the most frequently discussed of the occupational health issues, and for good reason, with some reports indicate that fishermen may work 24 -96 hours or more without restorative sleep. A reduction of sleep length to 4 or 6 hours for 14 days will cause cognitive impairments comparable to 48 hours without sleep. The danger with this is that people’s ability to judge their own level of fatigue is generally poor.  In another study comparing sleep loss with alcohol intoxication, 17 hours of wakefulness resulted in a performance drop comparable with a blood alcohol concentration of 0.05%, increasing to 0.10% after 24 hours. 
This is supported in an interview with an Alaskan fisherman, who when discussing sleep rotation, described shifts of 14 hours on and five off. He stated that this had the tendency to change with weather and fishing conditions, which
resulted in crew working around the clock to ensure a catch. While OSHA recommends having more crew on board to allow for longer sleep rotations, this is not enforced. 
Shift work disrupts the body’s circadian rhythm, which has been linked with increased chances of cardiovascular events, intestinal disorders, obesity and neurological events such as anxiety and depression – all problems highlighted in this community. [12,13] As the quality of sleep reduces with age, so does the body’s ability to cope with it, making this a major area of concern for the aging fishing population.
The sleeping environment itself has a significant impact on the quality of sleep, with noise, high room temperature and poor ventilation increasing psychological stress and reducing sleep quality.
The impacts of fatigue vary, with a recent survey highlighting mood swings, mistakes, falling asleep at the wheel, poor decision making and inability to concentrate as the most common. With 70-80% of maritime accidents thought to be the result of human error, this is a critical area of concern.  This exhaustion also contributes to the unhealthy behaviours observed in fishermen, such as poor diets and smoking. 
|Potential health concerns linked to fatigue and shift work|
Smoking levels among fishermen vary from area to area, with a common trend of an increased use of tobacco products while at sea. 81% Of male Turkish fishermen surveyed smoke, compared to 39.5% of the general male population. [15,16] On the other end of the spectrum, only 38% of Scottish fishermen smoke, compared to 23% of the general male population. This suggests that while areas with anti-smoking campaigns, such as those in Scotland, may be effective in reducing smoking within the total population, smoking may still be considered a cultural or social norm within the industry. [17,18]
Due to the confined space of a fishing vessel, all crew members are exposed to cigarette smoke regardless if they smoke or not. Research from the USA into the impact of passive smoking suggests that there is one smoker dying from an illness caused from second hand smoke exposure for every eight smokers who die from tobacco related disease. 
Studies in Nordic countries show an increased rate of cancers amongst male fishermen. Some of these will be classed as an Occupational Exposure Illness, whilst the location patterns for others strongly indicate the role of tobacco smoke as a causal factor. When the relationship between occupation and smoking was studied, it showed that the greatest health hazard to fishermen in North East Italy was lung and liver cancer, and the mortality from lung cancer was related to smoking. 
The weight of fishermen has been discussed in various studies, and when considering the risk factors indicated for obesity this may be more of a ‘correlation not causation’ case. Low education has been related etiologically with obesity. While education levels amongst fishermen vary by country, multiple studies indicate that fishermen involved in small scale fishing often have low formal education levels. [15, 21, 23, 24, 25]
In some cases, fishermen may be at an increased risk for weight issues than non-fishing males, such as seen in a Danish study indicating that 73% of the Danish fishing population was classed as overweight or obese, more than that of the local population. 
A 2015 study in Alaska had different results and indicated that 70% of surveyed fishermen were overweight or obese, which was consistent with that of the general population.  Regardless of the cause, obesity is still a significant concern to the health of the fishing community.
There are multiple health problems linked to excess weight, including:
|Health problems linked to excess weight|
|Type 2 diabetes||Heart disease and stroke|
|Fatty Liver Disease||Kidney Disease|
Evidence also indicates that obesity may increase the risk of certain other occupational diseases and conditions including musculoskeletal disorders, cardiovascular disease, asthma, vibration induced injury, and even the physiological and immune response to chemicals exposure on the job.  One study examined the role of obesity in alteration of the intensity of response to occupational hazards, including heat exhaustion and heat stroke in hot environments, physiological strain during the performance of hard physical work, respiratory strain and disorders during hard physical work and accidents involving equipment operators and other duties. It concluded that obesity should be considered a significant occupational risk. 
Dietary habits again vary from country to country, with nutritional intake remaining consistently poor.
One of the many challenges with on board nutrition is the perception the fishermen has on the quality of their own diet. Fruit and vegetable consumption in this demographic is low, with only 23% indicating they ate more than one serving of fruit or vegetable per day while at sea. Interestingly this same sample group still considered their diet to be good (21.7%), very good (24.4%) or excellent (6.3%) despite falling significantly short of dietary recommendations. 
In the short term, poor nutrition contributes to lower energy, concentration, and performance levels. High fat foods, irregular meals and large meals before sleeping may disrupt sleep and exacerbate gastrointestinal problems and can be linked to the high use of ulcer healing medications and antacids in fishermen. In the long term, serious digestive problems and nutritional deficiencies may occur, increasing the fisherman’s susceptibility to stress, injury, infection, and illness. [15, 20, 28, 29] Nutrition is also a key contributor to the weight issues discussed above.
|Dietary issues observed on fishing vessels|
|Diets lacking in essential nutrients||Inconsistent eating times|
|Reduced dietary fibre intake||Large portions|
|High fat and protein consumption||Increased caffeine intake|
|Low fruit and vegetable intake|
The factors shown in Table 4 all increase the risk for chronic health problems, such as diabetes, hypertension, cardiovascular disease, heart attack and stroke and some cancers. While no large-scale studies exist on these issues in fishermen, studies of general populations clearly demonstrate the relationship.
Chronic illnesses carry a high risk of acute and serious complications while at sea or might impair an individual’s ability to carry out safety critical tasks.  Unwell fishermen pose further risk to themselves and crew if these conditions remain undiagnosed or uncontrolled. Lifesaving equipment such as survival suits or lifejackets may be unsuitable or not fit those who are obese and those suffering from fatigue are more prone to making mistakes. Poor nutrition and fatigue are both linked to altered reaction times and decision making.
Figure 2: The Nutrition Cycle
2.) Occupational Exposure Impact
Fishermen often encounter dangerous substances, heavy lifting and high noise levels. While some attention has been placed on the immediate implications (such as asphyxiation, injury and death) little of the potential chronic health problems these may cause has been investigated. The use of and exposure to substances such as preservatives, carbon monoxide, refrigerants, diesel motor emissions and solvents are common. 
Asthma / Respiratory Diseases
It is estimated that up to 15% of adult asthma cases are associated with work place exposure.  Occupational asthma is frequently seen in the fishing industry and is associated with several types of fish and products used on board. It has been shown to be related to the exposure to crustaceans and molluscs such as shrimp, crabs, and shellfish. Chemicals such as sodium metabisulphite (SMBS) have also been shown to contribute to occupational asthma through single or repeated exposure. SMBS is widely used in the food and beverage industry, and in the fishing industry as a preservative, particularly for prawns.  Only 44% of respondents to a survey into the factors influencing safety of commercial fishermen had awareness of the procedures surrounding the use of chemicals / preservatives, which highlights this as being an area to which increased education should be considered. 
The medical tests on subjects exposed to the agent suggests SMBS induces inflammation and irritability of the airway by acting as an irritant. The smoking history of the subjects with this form of occupational asthma have been poorly recorded, so little conclusion can be drawn as to the importance of smoking as a co-factor. 
The development of respiratory problems is additionally significantly associated with working in cold conditions, exposure to gas and smoke, and biological hazards such as the processing of fishmeal and grinding of shells. [5, 6]
The most frequent health complaint among fishermen are musculoskeletal problems. These include a broad array of medical conditions involving muscle, tendon, nerve ligament and bone tissue. The injuries may occur acutely (trauma), or result from repetitive stress (overuse).  Musculoskeletal issues are seen to affect 67% - 91 % of fishermen, typically in the back and upper body. This occupational disease is typically caused by physically hard, repetitive or unfamiliar work tasks and working postures or sudden straining movements. Trips, slips and falls are also a contributing factor. When one considers the unstable work platform and characteristics of the movements required to haul gear or complete other tasks on board, it is unsurprising that injuries are common. [2, 5, 25, 36]
Carpal Tunnel Syndrome is a particular disorder common for salmon fishers or those working with a gill net. Spending for 18 hours a day detangling fish from the netting uses a lot of finger strength, often resulting in severe pain. The use of over the counter analgesics such as ibuprofen is frequently seen in an attempt to manage pain. 
Painful conditions such as osteoarthritis – can be the result of long-term repetitive movements or injuries to joints, and are often seen in professions such as fishing where long periods of standing, heavy lifting or other repetitive movements are required. 
Hazardous exposures at sea have been associated with chronic ill health. 
Occupational exposures are of the biggest concern to seafarers working in the engine room, where exposure to carcinogenic chemicals are most frequent. The use of different chemicals, such as lubricants which provide exposure to aromatic hydrocarbons, are widely seen in engine rooms. These products main method of penetration is through the skin, and exposure leads to significant risk of lung and bladder cancers. Asbestos exposure and diesel fumes are also of particular concern. [ 1, 39, 40]
|Increased cancer incidence rates for various cancers have been seen in fishermen|
It must be acknowledged that some of these cancers will have lifestyle influences and may not purely be the result of occupational exposures. The interaction between different carcinogens must be considered. This can be seen in a case study of a fisherman who was a smoker (lifestyle influence) and was exposed to asbestos in old paint (occupational exposure). The concomitant effect of these two substances on the risk of lung cancers is compatible with a multiplicative model. For a person exposed to asbestos, the risk of lung cancer is increased by exposure to tobacco, which can increase the risk of developing this cancer by 50 times compared to an unexposed person. A similar relationship has been noted between smoking and the exposure to diesel fumes and polycyclic aromatic hydrocarbons. 
Another example is cancer of the lip which is considered to be the joint effect of ultraviolet radiation from the sun and smoking. Skin cancers on other areas of the body however, are more likely to be more strongly associated with sun exposure, while the pattern of location for other cancers strongly indicates the role of tobacco smoke.[1, 41]
While studies have found an elevated risk of stomach cancer in fishermen, the cause of this remains unknown, but is likely to include occupational lifestyle influences. 
Decreased hearing as the result of noise exposure is well recognised within the industry. Those working in the engine room or processing areas are at extreme risk, as are those working with older equipment. The type of fishing will influence this, as well as the size and design of the vessel, and the individual’s job on board. The results of questionnaires in this area differ, with as little as 6% of respondents citing hearing issues, ranging to as high as 46% [ 6, 20, 42, 43] While noise levels may fit within OSH guidelines, exposure times at those levels are often significantly longer than recommended.
Figure 3: Noise exposure levels and durations 
Skin diseases affecting hands and forearms are common, with possible causes including acute or chronic contact with fish, seafood products and various agents. Algae, bacterial or marine toxins, gas produced by the decomposition of fishing products in anaerobic conditions, as well as chemical additives used as preservatives are all documented causes . As much as 25% of fishery workers report sensitive skin, 49.6% itchy skin, and 54% sun related injuries. [6, 29, 44] Infections can occur easily occur from fish spikes, inadequately cleaned wounds and other biological hazards 
|Causal Agents for itching skin in fishermen||%|
|Algae / Aquatic plants||49.3|
|Fish, crustaceans, molluscs, cephalopods, jellyfish||16.9|
|Other work – related causes (exposure to sun, mucilage, waxed protective overalls, bait, detergent / washing powders)||15.5|
|Non-occupational causes (weeds, bushes, dog fur)||2.8|
While this list only covers a small portion of the problem, it allows us to highlight the sheer scale of the problem. This is not a minor issue. With the rates of fishermen being impacted by any one of these conditions, it is likely that every single person working in this industry will experience a negative health outcome directly related to their career.
Work into some of these areas has already begun. The most frequently reported of these occupational healthy concerns, musculoskeletal conditions, have already been the top of many existing (albeit small scale) studies. The resulting information is enough to draw some conclusions on the mechanisms behind the injuries, and provides sufficient material to begin the development of educational material. Likewise, the topic of mental health and suicide rates in the fishing industry is the topic of a current study by Deakin University in Australia, which intends to provide an outline of the situation.
The need to raise awareness of the risk of developing chronic disease leading to permanent incapacity through health promotion and education has been established. Further studies and the promotion and development of educational resources should become a priority if there is any chance at improving the health outcomes of fishermen.
The FISH Safety Foundation will continue to actively investigate and share lessons learnt in this area. For further information into this work please contact Sam Holliday: firstname.lastname@example.org