It’s April. Is your boat in the water? Are your traps repaired? Are your ropes ready to fish? At what price to your health was all this work? Did you experience respiratory symptoms during the time you were working with the ropes and traps?
It would not be surprising if you answered “Yes” to all the above questions. The dust from handling ropes and traps can bring on congestion and perhaps a cough that hangs around while you are busy with the rope and traps, but which mysteriously disappears once you are back on the water and not indoors working with rope.
In occupational health and safety studies it is classic to find that symptoms disappear when workers leave a workplace environment that exposed them to dust, chemicals or repetitive tasks, for example. If you felt as if you had long-lasting congestion or a cold during the winter months when you worked inside with old rope and on other gear-related tasks, there is a good chance that you were exposed to a dust that contained endotoxin.
What is endotoxin?
Endotoxin is present in very low levels in the environment. It is present in higher levels in rural areas and in even higher levels in agricultural settings or where textiles are processed. Endotoxin is the material or dust which is left over when Gram-negative bacteria die (Gram-negative bacteria are those that don’t absorb a colored stain during the identification process). Endotoxin can be present in substantial amounts on dry trap rope. Algae and seaweed on rope and the rope itself harbor Gram-negative bacteria. When the rope is out of the water, the algae die, then the bacteria die, leaving a dust that contains endotoxin.
Making the connection between rope dust and endotoxin
Nearly 20 years ago, I went to Vinalhaven Island with several exposure scientists from the Harvard Chan School of Public Health. After taking a variety of particulate measurements in a lobsterman’s workshop, the researchers took some rope back to the lab and analyzed the dust on it for endotoxin. And guess what? The endotoxin level on the rope was very much higher than the background endotoxin level.
Lobstermen inhale the dust on ropes and traps when working with them. This inhaled dust results in symptoms that include cough or persistent cough with or without phlegm, tightness of chest, shortness of breath, increased susceptibility to lung infection and loss of pulmonary function with continued exposure. But because the symptoms of endotoxin exposure are similar to those of flu, colds and COVID-19, it is difficult for healthcare providers to differentiate between this exposure and the illnesses. Moreover, many doctors would not know to connect your symptoms with your exposure to rope.
Biofilms
Then there are biofilms. Biofilms are a collection of microorganisms that readily accumulate on living and inanimate material, such as algae, fish scales, and plastics. In a 2021 review article entitled “Microbial Life on the Surface of Microplastics in Natural Waters,” the authors stated that all the dominant microorganisms in biofilms that cover microplastic particles are Gram-negative bacteria. Surprisingly, different kinds of bacteria prefer different types of plastic. For example, the Alphaproteobacteria prefer the polyvinylchloride plastics (think PVC lobster buoys).
You can assume that there are biofilms of Gram-negative bacteria on algae, on the microplastics that are lodged among the algae, on poly rope, and probably on lobster buoys. Although a few of these Gram-negative bacteria may be pathogenic, they are not a problem until the bacteria die, and we inhale the endotoxin that is left behind as dust.
To reduce exposure to endotoxin on trap rope, the rope should be dunked in a hot water bath, such as the hot tank that some fishermen have on board, or put through a dilute chlorine bath. Perhaps also acceptable would be to give the rope a good rinse after being sun-dried, then dry it again before working with it. Regarding the PVC buoys, they probably do not present much of a problem, but they do “live” at the air/water interface that these biofilms enjoy. You might want to think about this if you are working with buoys (painting or taping) that have been in the ocean. The good news is that endotoxin-related symptoms will likely disappear once you are no longer working intensively with rope, buoys and traps, and are back on the water most of the day.
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