11. Safety notes
Aquaculture-related worker safety, especially for sea cages, requires a separate manual. Even so, a few relevant points that should be considered are briefly discussed in this chapter.
"SAFETY FIRST" are the two words, painted in capital letters, on the bridge that dominates many commercial vessel decks. A safe working environment is a MUST when people are working on the cages or boats in aquaculture (Plate 123). Risks for employees are increased on workboats at sea because of the use of tools and equipment in uncomfortable conditions, such as waves, wind and rain exposure. These environmental conditions make the work harder and increase stress and fatigue.
Specific regulations usually apply to work on the water. If no specific regulations for safety on cages are applicable, then comparable regulations on safety related to specific tasks (professional diving, working vessels, lifting equipment, etc.) may apply in cage culture operations.
The law does not usually require that every threat be eliminated, but it expects that risks are assessed and minimized and that workers are protected as far possible. Risk reduction and consequent increases in safety can be achieved through several actions, such as:
• Development of risk assessment plans, adoption of safety management systems, and identification of staff persons in charge of their implementation.
• Development of maintenance plans and maintenance scheduling for vessels, vehicles and lifting devices.
• Correct planning of daily activities. Overloading workers with tasks or underestimation of the correct number of people needed for a task may expose personnel to stress and fatigue, increasing the risks. Daily tasks should be planned according to the sea state forecast, avoiding heavy work (net changes, mooring maintenance, etc.) at times when bad weather is probable.
• Constant updating of staff training. Workers must be aware of possible risks, how these can be minimized, and how accidents are to be managed. The attention. level and conscientiousness of workers may be reduced if a task is considered "safe" - i.e. if it has been carried out many times without accident. However, risks can be everywhere. A culture of safety should be instilled.
PLATE 123
Hazardous conduct – loading of ropes and personnel on board a farm vessel
Availability of safety equipment that is in good working order. Workers must be protected and must be familiar with the use of protective equipment.
Have at least one or more workers trained in first aid, cardiopulmonary resuscitation (CPR) and in the use of an automated external defibrillator (AED).
Boats should be equipped with a radio that can be used in the event of severe accidents on the cage site. A radio distress call may be necessary to activate a first-aid response on land, or for requesting a rescue operation on the cages. Safety and rescue equipment must be available on board all vessels, including a life ring with lifeline, light buoy, flares, etc. Recommended standards and mandated regulations are usually provided by coastguard or other relevant authorities regarding the minimum type and numbers of safety equipment items to be stored on board any vessel, and their accessibility.
Suitable personal buoyancy equipment, such as lifejackets, should be provided by employers and should be worn by everyone while on workboats, and particularly during operations on cages.
Specific regulations on personal buoyancy equipment are usually available from the coastguard or other relevant authorities.
Helmets should be worn while a crane or other lifting device is in use, by anyone either operating or working in reach of the machine.
It is strongly advised that workers should not wear rings, bracelets and watches while working with nets because these objects can become caught in the netting mesh and may cause serious injury.
SCUBA DIVING
The use of divers should be minimized as much as possible, however when automated monitor systems to check the integrity and functionality of the farm are not available, divers provide a key support to the farm management and to ensure safety of the fish stock.
Professional diving, such as with scuba or hard-hat/hookah surface supplied systems, represents a significant source of risk for farm operators. Specific regulations for professional diving safety are usually established at the national level, but these regulations rarely address the specific challenges for cage farm divers. Therefore, safety rules and recommendations need to be adapted from the national regulations to the cage farm working environment, and then formally adopted by each company or aquaculture association.
Regulations and best practices that may be used as templates, or as references, are provided in detail by organizations and associations such as Health and Safety Executive (HSE), Association of Diving Contractors International (ADCI), International Diving Schools Association (IDSA), International Marine Contractors Association (IMCA) and others.
The appointment of a senior professional diver with specific skills on scuba safety. can support the cage farm management in the development of a dedicated risk analysis and prevention plan as well as in the supervision and audit of the diving team.
Only properly trained and licensed divers should be permitted on the farm. The use of professional divers is highly recommended rather than using farm workers to conduct occasional dives.
A safety buddy system should be mandated on the farm. Diving alone should be strictly forbidden. At least two divers must be assigned to complete any single task, with a third diver on the surface vessel, ready to provide assistance in the event of an underwater accident.
The bulk of farm diving work is usually done within the first 15-20 m. The maximum depth of diving operations depends on the specific tasks the divers are undertaking. Generally, depth profiles for each component are:
6-8 m for grid system maintenance;
0-15 m for cage maintenance and harvest operations;
15-20 m for sinkers and sinker tube maintenance.
These depth ranges are not particularly dangerous, and decompression diving should not necessary if the work is properly planned. Nevertheless, divers should always use conservative bottom-time estimates and conservative dive tables, and should always use safety stops. One recommended safety stop is at five metres for three minutes during any ascent.
The above-mentioned depth ranges are referred to 10–12 m deep cages. Specific safety procedures have to be developed and implemented for deeper fish cages (e.g. in tuna farming).
Decompression diving is frequently necessary when mooring lines and anchors need to be inspected or maintained. In this case, the diving must be carefully planned, with pre-dive assessment of the time to complete the tasks, the allowable bottom-time, the actual dive time required, and the number and duration of any decompression stops. This must be completed before starting the work.
All divers should always be equipped with a dive computer. This will inform divers of their present depth, maximum depth achieved, dive time, decompression stops (if needed) and safety stops. This tool could also be very useful to doctors in the event of an accident or a decompression illness that needs to be treated in a hyperbaric chamber. The diving data retrieved from the diving computer can be a great help to doctors if they need to determine the best hyperbaric treatment.
Some of the most common risks to be considered while diving in cage operations are:
• Becoming trapped in nets or ropes, mainly when harvesting or handling the harvest nets underwater or when passing through the diver door in the net wall. Equipment such as the dive mask or regulator may become entangled in the net (Plate 124).
• Ascent rate may be faster than normal or exceed a safe rate especially during harvest operations.
• Repeated "bounce" diving (yo-yoing) can represent a serious risk to divers, especially if the surface intervals are short, or if the dives are deep.
Divers are often required to work on mooring components that are operating under tension and where strong force loads are applied. Maintenance of these components may require the use of lift bags, hand-lever hoists (“come-along”) or boat cranes. The failure of a tool or a component under load or tension can cause accidents or exacerbate unsafe conditions.
Service vessel for divers must always be equipped with an oxygen supply unit that can be used for first aid in the field, in case symptoms of a decompression illness become apparent in a diver. All service vessel crew should be trained in the use of oxygen and other first-aid equipment, diagnoses and treatment of decompression illnesses or other barotrauma, and in the procedures for contacting farm management and emergency response services. Emergency contact numbers and communication equipment should be readily accessible to the boat crew.
PLATE 124
Protective cover made of knotless netting is wrapped around the first stage of a scuba diving regulator to reduce the risk of it becoming untangled in the seine net
SAFE WORKING LOAD
In any lifting operation, the safe working load (SWL; also called “working load limit” or WLL), of each lifting component must be respected and obeyed. The SWL is the load limit that is calculated by dividing the minimum breaking load (MBL) by some safety factor. This factor ranges from 4 to 10 and is usually provided by the component manufacturer.
For example, if a rope has a MBL of 1 500 kg and a safety factor of 6, the SWL will be: 1 500 ? 6 = 250 kg
The rope or lifting component must never be used for lifting heavier loads. The SWL of the weakest component must be considered the SWL of the entire rig in any lifting operation.