FISH FARMING TECHNOLOGY
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.
can occur when walking from a rough to smooth surface, and conversely, 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 harness 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
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.
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 ‘lifelines’ 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. 006 | INTERNATIONAL AQUAFEED | Fish Farming Technology
Published on Mar 16, 2015