WITH CASE STUDIES ON LIGHT FISHING: EXPERIENCES IN JAPAN Prof. Dr. Takafumi Arimoto
Tokyo University of Marine Science and Technology (TUMSAT), Japan
Background
The improvement of gear selectivity has been a traditional goal for fishing technology, for reducing of impacts from fishing, especially to minimize the waist of unwanted species and sizes. Selective fishing is achieved by means of mesh size enlargement, the use of a variety of by-catch reduction devices, as well as closed seasons and areas. This concept can be applied in an ecosystem-based approach for fisheries management, by identifying different zones (e.g. coastal and off-shore) with different biodiversity aspects, for different users of small-scale and large-scale fisheries, which require different management system. Historically, in the management system in the coastal waters in Japan, the Fishermen’s Cooperative Association created the “own- garden concept” with fishing access limited to the cooperative members. Sato-umi is another concept for sustainable and harmonious establishment of areas allocated to Nature and for human activities in the coastal area. In order to enhance the autonomous management concept, it is essential to provide technical support to identify the better, smarter usage of fishing gear in accordance with the specific type of capture and with the required selectivity performance for species and sizes in each gear type.
As a case study for technical approach to reduce the impacts from fishing, the application of Light Emitting Diode (LED) lamp for establishing the eco-harmonic fishing is reviewed through the experiences in the recent implementation process in Japan.
General Concept on Ecosystem-based approach
• What is Fishing Impact?
Fishing Impacts can be classified into several aspects as eco-system level and biodiversity impact including the direct impact to target resources, as well as the environmental impact such as habitat disturbance and pollutions. Both of the positive and negative impact should be well analyzed and described, for better understanding what is wrong, and what are the right things to do for minimizing the negative impacts and maximizing the positive impacts.
• Fishing Gear Selectivity-Function and Limitation
Gear Selectivity can be the tool for solution to reduce the impacts of fishing, by minimizing the discarding waist for unwanted sizes/species, but never be perfect for selectivity function, together with the awareness on fishing mortality of escapees.
Another new issue is the awareness on the undesirable effect of selective fishing for targeting the larger size group depleting from the stock, for resulting into the genetic disturbance to create the different characteristics for remaining the smaller size group in the stock. The very different idea is the balanced exploitation for maintaining the ecosystem, while we are far behind to understand the full image of ecosystem structure.
Long-term monitoring of catch composition for species and sizes is the key function to evaluate the impacts of fishing, for understanding the sustainability of the concerned fishing gear type in the concerned fishing ground. Then, the management approach is simple; needs to stop “overfishing by over-capacity of fishing activities”, but really difficult to do right things in anywhere of the world fisheries.
• Zoning for Fishing Activities and Role of Fishermen’s Cooperative
Another point for the sustainable approach is the zoning of fishing activities, especially to protect the coastal fisheries resources against the large-scale commercial fisheries such as trawl and purse seine. The problem is the present fishing regulation for zoning arrangement which is set through the distance from shore, depth range and boat size in each region, and not always fit in coordination with the ecosystem. Different scenario for fisheries management is required for different category of fishing activities, by fishing zone arrangement between the large-scale commercial fisheries and the small-scale artisanal/subsistence fisheries.
In case of Japan, the autonomous management system for coastal waters is covered by the local Fishermen’s Cooperative, with the limited fishing access only for Cooperative members. Each Cooperative sets regulations for fishing gear and methods with the fishing ground allocation, and coordinates with neighboring Cooperatives. Voluntary settings are also commonly implemented for the closed area/season together with the stock enhancement by seedling and artificial reefs, the fishing abstention days, and minimum landing size for marketing arrangement. The Cooperative actions are under the networking in each prefecture, under the umbrella of all Japan Federation with support and advice from National Fisheries Agency.
“Tragedy of Commons” is the reason of difficulty for management of coastal waters, while the concept of Local Commons can work as the front sea is the own garden under own responsibility, and the fish here is also own property with responsibility for keeping them to the next generation.
• Sato-umi movement
Sato-umi is another concept appealed in 2010 Nagoya CoP10 on Biological Diversity, defined as the dynamic mosaics of managed socio-ecological systems that produce a bundle of ecosystem services for human well- being. This concept of Sato-umi can work as the coastal management tool, through the human activities including fisheries going together with the Nature of coastal waters with symbiotic relationship on harmonious base. The participatory actions of city people can be also enhanced to enjoy the local amenities including fresh fish and fisheries products, local cultures and scenery of fishing villages, and to join the nature conservation program through the eco-tourisms.
Case studies on Light Fishing
• What is Impact of Light Fishing?
Fishing with light has been one of the most advanced and efficient methods for attracting and controlling fish and squids for capture purpose. All fishers/fishing boats wish to have higher lighting output than others for better catch, which is accelerated through the technical development of lighting devices for the Incandescent lamp, Halogen lamp and Metal halide lamp, so as to accelerate the lighting power competition among the fishing boats in the congested fishing ground. This resulted into cost increase due to the high fuel consumption, really the negative impact for fishers by decreasing the income in cost-benefit balancing. The negative environmental impact is the CO2 emission through the exhausting fumes, which is directly linked with the global warming issues.
The positive impact is the very species-selective capture function in case of squid jigging, while the negative biodiversity impact is the mixed catch of species and sizes in case of purse seine. Another negative impact can happen in the coastal waters for the small-scale fisheries through the very efficient way of attracting and catching with large-scale fishing.
• How to Monitor the Impact of Light Fishing?
The research process for evaluating the impact is firstly to monitor the lighting output and the underwater light intensity, thorough the direct measurement at sea, or simulation process to calculate the light intensity according to the lighting output. The comparative fishing with differed lighting output is very practical approach to evaluate the rational use of lighting devices and to prevent the excessive use of lighting outputs.
For this purpose, the evaluation of catch quantity and quality according to the lighting quantity ( kW and number of bulbs) and quality (color or wavelength patterns) can be helpful, together with the better understanding of Physiological and behavioral response of target and unwanted species to light.
• How to Minimize the Impact of Light Fishing?
Awareness building for cost-benefit balance is a good idea for changing the fishers’ attitude, to minimize the cost for fuel consumption on fishing light. For the challenging attitude to reduce the lighting output, the setting of the maximum level is required, otherwise the higher output boats can affect the catch of lower output boats in case of fishing in the close vicinity of the fishing ground. In this point, the distance among boats for positioning to fish can be the key for giving the fair opportunity among boats to attract and catch animals.
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Zoning of the fishing ground can be also of practical approach for protecting the small-scale fisheries in the coastal waters, against the very effective commercial fisheries with light such as purse seine. Even among the commercial scale boats, the zoning for fishing ground according to the fishing capacity such as the boat size, lighting output can be a good idea.
• LED Application for reducing the fuel consumption
The Application of Light Emitting Diode (LED) for light fishing is now progressing in Japan for the purse seine, stick-held lift-net and squid jigging as onboard or underwater lighting system. In the initial trial stage since 2000, the governmental supports have been deployed for installing the new devices of LED panels by replacing the conventional lamps, and for long-term monitoring the trend of catch and fuel consumption through the practical commercial scale operations, for confirming the decrease of fuel consumption. Even with the high investment cost for introducing new LED devices, it was confirmed for the stick-held lift-net to depreciate the initial cost in 5-10 years, by keeping the catch trend as before.
The LED application can also give the innovative fishing strategy to control the response of fish and squids, by means of the instantaneous on/off flickering patterns or of the color conditions with RGB mixture, for attracting, herding and barrier trapping, in order to develop the smarter usage of fishing light, including the species/size-selective control in the very near future.
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Annex 18