Mapping and removing ghost gear from our oceansJanuary 29 2018
Together with the Global Ghost Gear Initiative and World Animal Protection we are planning to use underwater drones in order to map accumulated ghost gear in the waters of Java, Indonesia.
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Underwater Drones and Ghost Gear in Indonesia
Abandoned, lost or otherwise discarded fishing gear (ALDFG), also known as ‘ghost gear’ accounts for approximately 10% of marine debris and has serious impacts on marine wildlife, habitats and fish stocks. ALDFG may result in reduced profits when it continues to fish (‘ghost fishing’) and increased operational costs for vessel owners/operators and authorities through the replacement of lost gear and retrieval efforts. ALDFG also represents a navigational and safety at sea issue.
Fishing gear has been abandoned, lost or otherwise discarded since the earliest time when fishing began, but extensive use of low-cost, durable and non-degradable synthetic materials in fisheries worldwide since the 1960s has dramatically accelerated and intensified the problem. The overall increase in fishing capacity and the targeting of more distant and deep water grounds has further escalated the issue.
Research shows that gillnets, traps, pots and fish aggregating devices (FADs) are some of the most likely gear types to become ghost gear, and can have the most severe impact on mortality and welfare of marine species.
World Animal Protection through partnerships in the Global Ghost Gear Initiative and with funding from the Food and Agricultural Organization of the United Nations has been undertaking a field project in two pilot sites in Java, Indonesia relating to the issue of ALDFG. Indonesia was proposed as region for the project due to the severe issues of marine debris, including ALDFG, known to originate there, coupled with increased threat of IUU and the stated recognition and willingness of the Indonesian government to take steps towards addressing it.
Gillnets were proposed as a primary focus of the project due to both their prevalence and impact as ALDFG. Gillnets, designed to catch fish by entangling them around their gills, have been found to be one of the most damaging types of fishing gear, along with trammel nets, if not managed properly and make up a significant proportion of global marine fisheries landings. Gillnets and other entangling nets are able to maintain high ghost fishing catch rates for long periods, years in some cases.
On our pilot site in Sadeng, where the fishers operate in deeper waters in the Indian Ocean in less favourable weather conditions, high rates of gear loss were reported, with one study estimating 35,000 pieces of gillnet being lost in the spiny lobster fishery each year. Due to the low value of gillnets and a government subsidy programme providing nets to fishers there is limited incentive to retrieve lost nets in either project site, although repair and reuse of damaged nets is commonly reported.
Despite awareness that significant numbers of gillnets are being lost in Indonesian gillnet fisheries there is no data about volumes based on aerial, beach or marine surveys. The current estimates are based on face to face interviews for a research project. Therefore, it is important to verify the data from the surveys in the pilot sites to ascertain how much gear is lost, whether it is ghost fishing and entangling marine wildlife and whether it can be safely retrieved.
Following conversations with all the parties we propose that a solution to bridge the data gap and understand the severity and prevalence of ghost gear in hotspot areas in nearshore gillnet fisheries, underwater drones could be programmed using AI to identify ghost gear and be deployed on survey missions.
Using sensors, AI and a camera we hope that drones will be able to demonstrate where ghost gear is accumulating and start to indicate what type of impact it is having. Data collected during the surveys will not only inform the future development of our solutions work in Indonesia but also provide vital evidence for the Global Ghost Gear Initiative data portal, which is a project aiming to create the first and only global data set on trends and abundances of ghost gear.
With this dataset many things be established: the main contributors of these accumulated piles of ghost gear can be educated, the scope of this problem can be visualised and, therewith, politicians can be presured into taking more action.
We know that large amounts of fishing gear are lost at depth in the Southern pilot site, but this is potentially unsuitable for the capacity of the drones due to the conditions. However, gillnets are commonly lost inshore rocky habitats in shallower conditions, so we propose the drones could be tested in this environment to determine some key research questions:
- How much gear has accumulated in the focus area?
- How are the currents effecting the accumulation of ghost gear?
- Is there evidence of wildlife and marine flora entanglement?
- Is the gear in a position that indicates it can continue to ‘ghost fish’ (ie- hanging vertically in the water column, rather than snagged and rolled up on the sea bed?
- Is the gear safely retrievable?