Fishing gear has been lost, abandoned or otherwise discarded in all seas and oceans ever since fishing began. The extent and impacts of the problem have worsened significantly in recent years with the increasing levels of industrial fishing and also the increasing durability of fishing gear. Fishing activity has now extended to previously untouched offshore and deep-sea environments, which are often very sensitive to the impacts of abandoned fishing gear.
The most notable damage caused by ghost nets is the entanglement of marine life that affects not only the most visible marine animals like seals, sea lions, dolphins, whales and sea turtles, but also affects commercially important fish populations with direct impact on human coastal communities.
Ghost nets understandably concern us for environmental and ecological impacts. However, the increasing safety risk for navigation also deserves attention, especially considering that various cases of injury and loss of human life have been recorded.
Ghost nets removal is a complex dive operation that requires time and intensive labor, can be a challenging but also satisfactory experience, and often requires an extended team including working and safety divers as well as surface support personnel. There are several aspects to consider when planning a removal:
• Site inspection
• Equipment to be used
• Safety and emergency equipment
Unfortunately, there are no standards, practices or guidelines to properly face this problem; all techniques used today are relatively arbitrary. The actual procedures are typically created by sport diving instructors who know about technical diving and applied their knowledge and experience, or a public safety diver who learned how to remove fishing gear, in some cases these procedures do not meet the actual needs of the job, especially on safety. These techniques are generally not tested and are not discussed in forums with experts.
Removing any object from the sea bottom is a demanding task. It is an advanced diving activity that requires previous experience most likely in different environments and situations, excellent buoyancy control and skills to multitask and manage cutting devices, lines, ropes, clips, surface markers and lift bags. It is technical diving but not the technical diving associated with mixed gas, deep and extended time rather is it is technical in that it requires specialized training, procedures and guidelines.
Any diver participating in net removal should be trained at minimum as an Advanced Diver and on the use of Search and Recovery gear and techniques; keep in mind certification is not necessarily qualification. Before the actual dive operation, practice in the use of lift bags, cutting devices, ropes and lines on a controlled situation are highly recommended. This also generates team coordination and awareness of adverse situations or gear complications. Communication among the team members is crucial as underwater communications are limited; the use of hand signals and slates are essential, but must not replace an extended briefing about the upcoming task.
As a part of the process several topics need to be discussed, including but not limited to: weather, water conditions, equipment, pre-dive check, dive plan, safety and contingency procedures. The length of the briefing will be dependent on the team experience and environmental conditions. It is also important to consider the size, material and weight of the fishing gear to be recovered.
On site, prior to commencing the operation, an extensive briefing must cover both safety and operational aspects; like entry and exit points (using the appropriate method of getting into and out of the water could make the difference in the success of the dive) and discussing any hazardous features at the dive site, like currents or the presence of particular flora, fauna and boat traffic.
The Team Leader has to be sure all divers understand their roles and the specific use of all pieces of gear to be needed. Furthermore, a well-trained surface support team is also vital.
Ghost net removal is both equipment and personnel dependent. Sometimes, the simplest problems can easily evolve into major complications.
The recovery team should be capable of operating with perfect coordination, have an in depth knowledge of their gear and fully understand its capabilities. In many cases technical diving skills and gear configurations are needed. Being prepared to face different circumstances is always a challenge, because there is no consistency and similar situations may use significantly different procedures. Awareness and preparedness are useful tools.
There are some situations that may represent a risk for the participants. A diver getting entangled in the fishing gear is probably the most notorious, but we must also consider increased gas consumption due to hard work. Other factors to be considered are that in some cases the operation will be conducted at the same depth (square profile), perhaps the chances of running out of time and gas are larger, and water may be low in visibility because the sediment accumulated around or under the fishing gear. In most of the cases a single dive will not be enough to recover the fishing gear; when multiple dives are need it to complete the recovery task, it is necessary that a careful check of the gas upload in every diver is carried out and that the Team Leader is aware of any decompression requirements and plans accordingly.
Once the objective is located, the dive team performs several last minute checks for safety, adjustments to the dive plan as well an update on actual situations like sea conditions (currents, visibility, temperature), any marine life entangled and how to carefully release.
There is no recipe for dealing with underwater ghost gear removal. Only properly trained, qualified and competent advance divers can participate.
The first step is to cut and move the gear away from the live reef or the entanglement structure, with surface markers attached to provide awareness to the surface support team. Using ropes and lift bags, the ghost net can then be prepared for lifting and the boat crew will help to lift it on board.
Finally, divers document the sea bottom using video and photographs. With proper technical training, they will be able to use the minimum of technical resources needed to obtain the best possible results at the lowest cost and with a methodology that is simple to execute.
Strictly following safety procedures and committing to training, planning and coordination, will ensure that these vital operations are conducted safely.