Safety on Aquaculture Farms

FISH FARMING
TECHNOLOGY
SUPPLEMENT
Safetyon Aquaculture Farms
SUPPLEMENT

A
quaculture has many hazards that are expected when
agriculture in an aquatic environment is performed.
Avoiding injury maintains aquaculturists’ health and
quality of life as well as their economic security. Injury
can be costly due to lost work hours, medical expenses and
possible lawsuits, so maintaining safe working conditions on fish
farms has multiple benefits.
Occupational safety survey research performed in the US
(Melvin Myers, Robert Durborow, Henry Cole, Tiffany Ogunsanya,
et al. from 1997 to 2012 – see below) and the U.K. (Durborow
and Gomelsky, unpublished, presented at the U.S. Trout Farmers
Association annual meeting, Denver, Colorado in September 2012)
identified twelve potential hazard categories present on aquaculture
farms: muscle strains, falls, entanglement, drowning, electrocutions,
working in confined spaces, equipment overturns, chemical expo-
sures, impalement, self-injections, dark working conditions and lack
of emergency communication.
In safety studies, the old adage of “being careful” is considered
the least advanced of injury prevention intervention, avoiding the
hazardous behavior is a bit more advanced while engineering the
work environment to eliminate the hazard is considered the most
advanced intervention.
Muscle strains
A common muscle strain occurs in the lower back region, often
caused by lifting and carrying heavy loads. Leg muscles rather than
back muscles should be used primarily to lift heavy weights and twist-
ing (turning the upper body independent of the lower body) while
holding a heavy load should be avoided.
A fish production facility in the US found that if workers carry
smaller, more manageable loads of fish in nets, they avoid muscle
strains, increase the speed of transferring fish between tanks, and
avoid inadvertently dropping fish out of overloaded nets onto the
floor (which not only stresses the fish but slows down the fish-
moving process). In the effort to increase fish farm safety, one could
by Robert M Durborow, Professor and Aquaculture
Specialist, Kentucky State University, and Melvin L. Myers,
Associate Professor and Safety Engineer, Emory University
Rollins School of Public Health, Atlanta
SAFETY
on aquaculture
farms
002 | INTERNATIONAL AQUAFEED | Fish Farming Technology
FISH FARMING TECHNOLOGY
Figure 1: Feed trucks eliminate the need for handling feed.
Figure 2: This hydraulic feeding system runs feed from the
feed bin through a pipe out to chambers located above the
raceway water. This feeding mechanization eliminates much of
the labour, repetitive motion and muscle strain involved when
feeding is done manually.
Figure 3: The two pulleys above this dip net reduce the load
weight by a half, and the whole net system can slide on a
metal track (where the blue scale is) to the end of the tank for
unloading.

“be careful” while carrying feed bags around a farm or, better yet, one
could use a truck or utility vehicle to transport the bags, but the best
option for avoiding muscle strain during feeding is to fill a bin on a feed-
ing truck and mechanically blow the feed from the bin through a pipe
to dispense it into the ponds or raceways (an engineering intervention;
Figure 1).
A large trout farm in the US eliminates the truck and simply augers
the feed from a stationary feed storage bin through a pipe that has dis-
charge ports over each raceway receiving a pre-determined amount of
feed programmed by computer (Figure 2). Other interventions designed
to reduce muscle strains include keeping the fish tank loading dock at
the same level as the fish hauling truck bed to avoid having to step up
and down while carrying heavy loads; constructing fish hauling tanks
to be waist-high so heavy loads of fish in a dip net do not have to be
hoisted chest-high; using metal chutes at the hauling tank discharge ports
to allow for quick and easy stocking of fish; using dip nets attached to
pulleys for easy lifting and a track for sliding (done manually in Figure 3
and mechanically in Figure 4); and using cranes and forklifts for all general
lifting activities on the farm (Figure 5). Water pumps (Figure 6) and fish
pumps (Figure 7) save time and prevent muscle strain.
Fall prevention
Settings with water, and possibly ice, have the inherent hazard of
potential slips, trips, and falls (which includes the obvious risk of drown-
ing after a fall). Walking on trout raceway crosswalks or on the narrow
raceway walls themselves involves risks especially if the crosswalks
are broken, rusty or splayed and the raceway walls are crumbling or
simply very narrow. Metal crosswalks in good condition with traction/
grip (‘grip-strut’) and widened raceway walls (wide concrete in Figure
8 and wide metal ‘grip-strut’ attachments in Figure 9) reduce falling
risk. Wooden surfaces can be given more traction even when wet
by veneering with rough, unfinished lumber or attaching chicken wire
to the surface (commonly seen in the U.K.). Newly poured cement
surfaces can be given a rough texture by a coarse broom before the
cement dries completely (Figure 10); this helps to avoid the extremely
slippery wet smooth cement that poses an extreme falling hazard. Slips
Figure 5: Oxygenated fish-holding buckets are carried and
elevated by forklifts to load baitfish on this Arkansas minnow
farm’s live haul truck.
Figure 6: Water is pumped into tanks conveniently as the
hauling truck drives underneath the water supply pipe. This
alleviates the need for filling up tanks manually bucket-by-
bucket.
Figure 4: The overhead crane in this photograph can move
heavy loads of minnows between tanks and onto live haul
trucks.
"Injury can be costly
due to lost work hours,
medical expenses
and possible lawsuits,
so maintaining safe
working conditions
on fish farms has
multiple benefits"
Fish Farming Technology | INTERNATIONAL AQUAFEED | 003

Figure 10. Rough concrete floors, providing traction even
when wet, can be created with a coarse broom when the
newly-poured drying concrete is still wet.
Figure 11: The red pipe on this feed bin extends up to the bin
top allowing feed trucks to fill the bin from ground level. This
intervention engineers the falling hazard out of this farm task.
Figure 7: In the back of the truck is a fish pump mounted
to the right of the oxygen cylinder. Pumping fish onto the
truck during loading is more efficient and safer than dip-
netting or using a crane to move them.
Figure 8: The tops of the raceway walls at this federal
facility are wider (14 inches wide) than the walls themselves
(about 10 inches wide). This width is noticeably wider than
the top of most raceway walls. The U.S. government’s
Occupational Safety and Health Administration (OSHA)
inspects this hatchery because it is a federal facility.
Figure 9:
Raceway walls
can have a
metal crosswalk
bolted onto the
top; the extra
width is just at
the top where
the worker must
walk, while
the raceway
wall itself is
fairly narrow.
This allows for
a maximum
amount of
water for
the fish and
a minimum
amount of
cement to pour
the wall (thereby
conserving
costs).

Figure 15: Those working near or on
equipment must take precautions to
assure that the power in the breaker
box is turned off and locked. The
Lock Out–Tag Out system should be
practiced; a worker doing equipment
repairs locks the breaker box in the off
position and a second worker working
on another piece of equipment coming
off of the same breaker box also locks
the breaker box switch so that one
worker does not complete his job and
then return to the breaker box to turn it back on while the
other worker is still working on his piece of equipment.
Figure 16: This ground fault
interrupter (GFI, also called a
ground fault circuit interrupter,
GFCI) is used in the power box of
a permanent electric paddlewheel
aerator. On this farm, two workers
were in the pond rewiring a
paddlewheel aerator (all power
was turned off while they were
working on the wiring). After they
finished the rewiring, a third worker turned the aerator on
prematurely while they were still in the water (one waist-
deep and the other ankle-deep). Both men received heavy
electrical jolts, especially the worker who was waist-deep.
The shock occurred because the workers had erroneously
connected the ground wire to the hot, and the hot wire to
the ground.
Figure 17: Trout farm waste in North Carolina is collected
in concrete reservoirs where it is held until it can be used
for things such as agricultural field fertilization. Drowning
and exposure to toxic fumes are potential hazards in
these concrete tanks. Geo-tubes are an alternative waste
collection method. Hydrogen sulfide and carbon dioxide
are decomposition products from fish waste. Both gases
are heavier than air (i.e., have a higher specific gravity)
and both can accumulate, even in an open topped tank.
Even when tanks are empty or nearly empty, workers
entering tanks for cleaning and maintenance can be
overcome by harmful gases. Unconsciousness can result in
a few seconds and death shortly thereafter. Even worse is
that approximately one third of such deaths are to other
workers who entered such structures to rescue a colleague
and, as a result, also died.
Figure 12: The side-mounted walkway on this fish hauling
truck is swung down to be used as a walking and standing
platform during loading and unloading of fish. Most live haul
trucks have this hinged platform, but the unique feature on
this truck is the retractable guardrail that rolls out from the
tanks.
Figure 13: The netting mounted on the wooden frames keeps
birds and other predators out of the trout raceways and
can also break workers’ falls, preventing possible drowning.
The neat mounting of the netting also helps to prevent
entanglement that may occur if it were loosely draped over
the raceways.
Figure 14: This PTO shield is cut near the tractor to allow for
lubrication to be applied. The farm owner recommended that
PTO shield manufacturers provide a way to lubricate the PTO
shaft without having to remove the shield. PTO shields protect
farm workers from getting caught and entangled in this
rapidly spinning tractor part.

can occur when walking from a rough to smooth surface, and con-
versely, trips can occur when walking from a smooth to rough surface.
Falls from high places like the tops of feed bins can be avoided by
active safety measures such as enclosed metal guards surrounding the
metal ladder on the feed bin sides. Active safety measures require the
person to play a role in their safety such as catching oneself on the
metal guard in the event of falling. An engineered safety intervention
of having a cable attached to the feed bin lid that can be pulled from
ground level to open the lid eliminates the need to climb to the top,
and an even better engineering intervention is having a pipe extend
from the feed bin top to ground level where a feed tanker truck can
attach to the pipe and blow feed into the top of the feed bin (Figure
11).
In cases, however, when someone needs to climb ladders, a har-
ness attached to a cable paralleling the ladder can be worn by the
worker. Usually when a worker is on a hauling truck side platform, the
potential fall is only three or four feet unless the truck is parked on a
ledge or steep levee; under this scenario, falls could exceed 20 feet.
To safeguard against such hazards, an Idaho trout farm has engineered
retractable guard rails for the side of their hauling trucks (Figure 12).
Under icy conditions (on hauling trucks or elsewhere on the
farm), salt can be applied to melt ice or prevent it from forming. To
increase traction, one Kentucky operation surfaced their trucks with
SlipNOT® high traction metal plating (“pepper plate”) that is also
used on battleship decks.
Entanglement, drowning and electrocution
Loose and random placement of bird netting around raceways
and ponds can present an entanglement hazard that can lead to
drowning. Using a more rigid netting material fastened to wooden
frames is effective in excluding bird predators without posing a
drowning hazard; additionally, workers falling into these structures will
likely have their fall broken, reducing the chance of injury (Figure 13).
Drowning can also be prevented by having anchored rope ‘life-
lines’ extending into ponds, especially ponds with slippery rubberized
pond liners on the levees. Aquaculturists should also be aware of a
rare drowning threat present at wastewater treatment facilities; fish
are sometimes produced in decommissioned (retired) concrete tanks
at wastewater treatment plants. Some bodies of water at these plants
are aerated so intensively that the water loses its buoyancy friction,
making it impossible to swim in the “foamy” water.
Another type of entanglement that can occur on fish farms is being
caught in a tractor’s power take-off (PTO) while aerating a pond or
being caught and traumatized in a paddlewheel aerator. PTOs should
have a protective guard to prevent workers from having their clothing
Figure 20: A safety precaution commonly practiced in the
coal mining industry is to construct an earthen berm on the
edge of the road to deflect truck or tractor tires away from
the drop-off.
Figure 18: This confined space used to collect fish waste has
pump controls that have been moved to the pit’s surface
eliminating the need for workers to go down into the pit/
confined space. Previously this hole was covered with a
metal lid with a manhole in it. A tripod had to be used
on top of the hole with a tether attached to a worker in a
harness.
Figure 19: The dual tires in the rear of this tractor and the
wide-set front tires help to keep this tractor from rolling over
when on steep terrain including pond banks. The cab acts
to protect the driver from injury in the event of a roll-over
and maintains a controlled temperature to prevent hyper- or
hypo-thermia. The side of the cab with the door (left side in
this picture) should always face away from the pond water
when driving on the levee top (the driver could easily exit
the cab if the tractor landed in the pond on its right side).
Modern tractors with cabs have breakout panels at the rear
for a second exit, and tractors in Scandinavian countries
have an escape hatch at the top of the cab.

caught in it and being spun and beaten to death on the ground (Figure
14). Likewise, aquaculturists working near or on a paddlewheel aerator
must take precautions to assure that the main breaker box as well as
individual aerator switches in the breaker box are turned off.
The Lock Out – Tag Out system of breaker box locking should be
practiced (Figure 15); a worker doing electrical repairs on an aerator,
for example, locks the breaker box in the off position and a second
worker working on equipment coming off of the same breaker box
also locks the breaker box so that the first worker does not complete
his job and then return to the breaker box to turn it back on while the
second worker is still working on his or her piece of equipment. This
prevents both workers from being exposed to entanglement trauma as
well as electrocution hazards.
Also in the realm of electrocution prevention, ground fault inter-
ruptors should be used around outlets and on breaker boxes (Figure
16). A farm in North Carolina raised their overhead electrical wires
from their original 30 foot height up to 45 feet to prevent cranes from
contacting the wires when moving trout between raceways. Another
precaution taken by a fish farm in Arkansas is to use only gasoline-
powered power washers; one of the farm owners was killed using an
electric-powered washer when the plastic insulation on some internal
wires eroded away allowing the metal wires to come into contact with
the metal casing of the washer.
Confined spaces
Toxic gases that are heavier than air (such as hydrogen sulfide and
carbon dioxide) can accumulate in deep confined spaces including in-
ground manure collection tanks on trout farms (Figure 17). Calibrated
multi-gas monitors should be lowered into confined spaces to test air
quality before workers descend into them, and in all cases these work-
ers should wear harnesses and be observed/assisted by a co-worker
at ground level. As with other safety issues, engineering the hazard
out of the procedure is the best approach; figure 18 shows a confined
space at an Idaho trout farm where the controls have been moved to
where workers at ground level can make adjustments without entering
the space.
Equipment overturns
Farm equipment (notoriously tractors) can roll over and crush the
driver unless a proper rollover protection structure (ROPS) is used.
A combination of a roll bar or enclosed cab with a seatbelt keeps
the driver in a protected zone of the equipment. Using dual tires on
tractors adds to their stability (Figure 19). Proper management of
the farm’s roadways, especially on levees, can also help to prevent
rollovers. Maintaining an adequate gravel surface and repairing areas
Figure 21: Mounting a metal screen on the tractor ROPS can
block debris (rocks, logs, etc.) propelled toward the driver.
Figure 23: Locking hinges on hauling tank lids prevent
them from being blown closed onto workers’ hands.
Other techniques for keeping tank lids open include using
wedges, bungee cords and screw-down clamps.
Figure 22: Workers should protect their arms and hands by
wearing long rubber gloves when using chemicals such as
formalin for treating fish pathogens.

where the road has eroded (or at least keeping grass mowed so any
washed-out areas can be seen and avoided more easily) can keep a
vehicle from sliding or rolling off the road and into a pond.
Additionally, the water in a pond can erode the levee causing a
cavity into the levee in which the under-cut can give way from the
weight of equipment on the levee. This erosion can be mitigated
with aggregate at the interface between the levee and water. A
safety precaution commonly practiced in the coal mining industry is
to construct an earthen berm on the edge of the road to deflect the
truck or tractor tires away from the drop-off (Figure 20). An addi-
tional safety intervention is to mount a metal screen on the tractor
ROPS to block debris (rocks, logs, etc.) propelled toward the driver
(Figure 21).
Chemical exposures, impalement, falling
hauling tank lids, and self injection
In a somewhat miscellaneous listing of potential hazards in aqua-
culture, respiratory, eye and skin protection (Figure 22) should be
worn when applying chemical treatments including fertilizers, disease
therapeutants and herbicides. Protruding rebars used to enforce the
strength of concrete should either be capped with plastic protectors
or bent to a horizontal position to prevent impalement. Bruises and
cuts can also occur from falling hauling tank lids; hands have been
broken and fingers can be severed. This can be prevented by install-
ing locking hinges (Figure 23) or even by using lightweight lids (e.g.,
sheet metal).
When injecting trout with vaccines, corrugated fiberglass roofing
material (Figure 24) can help to stabilize the trout to prevent them
from making sudden movements that could lead to self-injection by the
worker. Accidental injections of fish vaccines into people can cause a
strong inflammatory response or even anaphylactic shock (if the person
had a previous accidental injection of the vaccine). If previously injected
with a fish vaccine, a person should consult a physician about keeping
an EpiPen® injection kit handy in the event of another inadvertent
vaccine injection. Moreover, automatic fish vaccination machines have
been produced in Norway and Denmark that eliminate manual vac-
cination of fish.
Dark working conditions and
lack of communication
Much work on fish farms takes place at night, a time when vis-
ibility is compromised. Being visually restricted makes it more likely
for farm workers to experience injury; sufficient lighting can help to
reduce this risk. Aquaculture ponds often require aeration at night
when respiration is at its peak and fish experience low oxygen
stress. Working in a hurried fashion in an attempt to save as many
hypoxic fish as possible while not being able to see very well can
result in serious injury; a catfish farm manager in Alabama had
electric cables powering pond aerators get tangled under his truck
in the middle of the night – his attempts to free the wires resulted
in his electrocution. Similarly, on a North Carolina trout farm in the
middle of the night during the winter, the water intake to the trout
raceways was frozen and clogged; a farm manager died during his
attempt to clear the intake and restore the water supply. In both
cases lighting was inadequate. Installing bright overhead lights on
utility poles and on pickup trucks can provide increased visibility to
make the nighttime tasks less risky.
Having adequate communication during emergencies can help to
avoid tragedy. Mobile telephone service in remote locations (typical
of many fish farm settings) is often unreliable. Fish farmers in rural
Alabama often rely on two-way radios to reach co-workers or family
members during such emergencies.
The objective of presenting this aquaculture occupational safety
information is to make aquaculturists aware of potential hazards in the
fish farm workplace and provide ideas on how to avoid or eliminate
them. The text should be helpful in explaining these ideas, but the
photos and captions may even be more helpful by triggering the
thought process involving circumstances that are similar to those on
the reader’s farm. For more detailed information and references, please
contact robert.durborow@kysu.edu.
Figure 24: Trout are held securely on this vaccination table for injection. The corrugated surface prevents the fish from
moving or slipping, reducing the chances of self-injection. Severe anaphylactic shock can occur when workers are
injected with trout vaccines, especially if they had been accidentally injected previously. Consult a physician to see if
carrying an EpiPen® would reduce workers’ risks.

Safety on Aquaculture Farms

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