EARTH OBSERVATION OPPORTUNITIES IN THE FISHERIES AND AQUACULTURE SECTORS

Transcription

1 EARTH OBSERVATION OPPORTUNITIES IN THE FISHERIES AND AQUACULTURE SECTORS T.G. Boivin (1), A.M. Dean (1), D.W. Werle (2), E. Johnston (1), G.S. Bruce (1), P. Suvanachai (3), O. Tsui (1) (1) Hatfield Consultants Ltd., Bellevue Avenue, West Vancouver, British Columbia, Canada, V7V 1A6 (2) Ærde Environmental Research, Box 1002, 5112 Prince Street, Halifax, Nova Scotia, Canada, B3J 2X1 (3) Fisheries Information Technology Division, Department of Fisheries, Bangkok, Thailand, ABSTRACT Aquaculture ranks among the most dynamic food production industries in the world, with an annual growth rate of 9.2% since 1970 [1]. Both the fisheries and aquaculture sectors are facing strengthened regulations, with an emphasis on improving sustainable growth and environmental protection. The New Earth Observation Markets for Fisheries and Aquaculture (NEMA) project has established a number of opportunities for the application of EO technologies in these sectors, where present levels of utilisation are currently low. Several EO initiatives are now underway, including the development of monitoring and warning systems related to algal blooms, which can have negative impacts on aquaculture production facilities. However, such applications require significant technical and service development within the global fisheries and aquaculture sector. Additional opportunities are also emerging because of other environmental market drivers. 1. INTRODUCTION The ESA funded project initiative, New Earth Observation Markets for Fisheries and Aquaculture (NEMA) is targeted at the fisheries and aquaculture industries, and in particular, large multi-national companies operating in these sectors. Generally, the term fisheries describes the collective enterprise of harvesting fish from water bodies for either commercial or recreational purposes. It may involve capture of wild fish or cultivation of fish through aquaculture. The goal of the NEMA project is to determine the main market forces that influence and drive the fisheries and aquaculture sectors, and to elaborate appropriate responses for the EO industry to address these market drivers. Knowledge of these emerging market forces will help to identify opportunities for the application of innovative EO technologies and the development of customized services. Hatfield Consultants Ltd. (Hatfield, Canada) is the prime contractor for this project, and is supported by the following organizations: Apolloni Virtual Studio (Italy); Ærde Environmental Research (Canada); Nefisco Foundation (Netherlands); and Strata360 (Canada). EO service industry reviewers included ACRI-ST (France) and DHI Water and Environment (Denmark). 2. KEY MARKET DRIVERS IN THE FISHERIES AND AQUACULTURE SECTORS A number of factors influence the demand for EO in the aquaculture market sector: Emphasis by industry and government to increase production and product quality; Increasing pressure to minimize environmental impacts; Increasing conflicts over site location and new site selection; and Strengthened environmental regulations and improved governance of the sector. Within the capture fisheries sector, the main driver is improved management and conservation of fish stocks: Efforts to address illegal, unreported and unregulated (IUU) fishing, through implementing port and trade regulations. Increasing role of Regional Fisheries Management Organizations (RFMOs) in resolving resource conflicts, overlapping jurisdictions, and international disputes; and Enforcement of Marine Protected Areas (MPAs) as progress is made toward sustainable management of marine resources. Proc. of the 2004 Envisat & ERS Symposium, Salzburg, Austria 6-10 September 2004 (ESA SP-572, April 2005)

2 2.1 Environmental / Health Environment factors play a critical role in the selection, maintenance, and management of aquaculture sites. For instance, water quality is a key environmental parameter for successful aquaculture operations, but other factors such as currents, waves and weather also play a significant role. Also, aquaculture can also have adverse impacts on the surrounding environment, and monitoring of water quality is essential for both regulators and operators. Harmful algal blooms (HABs) cause significant financial losses within the aquaculture industry and result in increased consumer concerns over healthrelated issues. For the aquaculture industry, this is one of the key environmental drivers generating a demand for new techniques to monitor and predict HAB events. Information is required to prevent losses at existing facilities, and to improve the site selection process for new facilities. Within the capture fisheries sector, monitoring water quality and habitat degradation in MPAs are likely to be important drivers with regards to the demand of geo-information products and services. 2.2 Political / Legal The rapid growth and industrialization of the aquaculture industry, coupled with growing competition for resources, has focused attention on the need for enhanced policy measures and regulatory frameworks in order to better manage the sector. There are significant differences in the design and operation of aquaculture industries in North America and Europe, as well as in Latin America and Asia. Environmental regulations and enforcement efforts differ significantly, depending on the technology employed, history of development, and cultural perceptions on fisheries and natural resource development. Formulation of appropriate regulations in many countries is constrained by a shortage of information on aquaculture facilities, their designated lease boundaries, interaction of aquaculture production systems with the environment, and impacts of facilities on the environment. This presents an opportunity for the EO sector to provide useful, accurate and timely information in support of environmental management and monitoring. The challenge for the EO industry will be to identify measurable criteria for monitoring parameters, validate and integrate EO within existing systems, and effectively lobby governments and industry to include EO as part of regulation and monitoring systems. 2.3 Economic Global production from capture fisheries and aquaculture is currently the highest on record and remains a significant factor in global food security. The aquaculture industry is the fastest growing food production sector in the world, having grown at an annual rate of 9.2% since 1970 [1]. In 2002, the international trade in fish products increased to a new record of US$ 58.2 billion; the market share of world fish exports from developing countries, in value terms, is just over 50% [2]. Reported global capture fisheries (excluding China) are relatively stable, or have declined slightly since the late 1980s, but there are significant regional disparities [1]. In many areas, capture fisheries are in crisis, due to economic pressures, or from ecological changes in the structure of marine food webs [3]. 3. KEY OPPORTUNITIES The NEMA project has identified several key opportunities for EO related products and services in the fisheries and aquaculture sector. 3.1 Aquaculture Mapping and Monitoring The formulation of appropriate regulations is affected by a shortage of information on the precise location of facilities, and interactions between aquaculture production systems and the environment. Even where information is available, predictive models for aquaculture-environmental interactions still require considerable improvement with regard to their accuracy, general applicability and affordability. Aquaculture facilities include fish cages, pens, and traps, as well as hatcheries. In addition, ponds are common, particularly for rearing of shrimp. Experiments aimed at detecting aquaculture facilities by means of EO satellite have been conducted with a variety of imaging instruments, including radar. Useful results were obtained from RADARSAT-1 Fine Mode and ERS 1 & 2 SAR image analysis [4], [5]. High resolution optical data (e.g., IKONOS or QuickBird) has mapping potential, but may be limited by cloud cover and relatively high cost. Alternating Polarisation Envisat ASAR data has yet to be thoroughly investigated with regard to facilities detection; however, insufficient spatial resolution is a likely limiting factor. Of particular interest in this respect are the forthcoming RADARSAT-2 and TerraSAR-X radar systems. Offshore aquaculture technology has received significant attention in recent years, although

3 environmental, legal, regulatory, and technical issues are yet to be resolved. Major initiatives are underway, such as the Farming the Deep Blue forum [6]. Future movement toward operational offshore farming offers a clear opportunity for EO to provide important scientific data, regular mapping and monitoring products, and optimal site selection data (see Section 3.2 and 3.3). 3.2 Water Quality Monitoring Important water quality measurements around aquaculture production sites are currently obtained through in-situ water sampling, with subsequent laboratory analysis. The following are prerequisites for such monitoring: High temporal and spatial resolution; and Known accuracy. Integration of local in-situ sampling with regional measurements obtained through remote sensing may produce cost-reduction benefits and extend spatial coverage. EO has its strength at the medium and large temporal and spatial scales, and its best use is made as a complement to in-situ sampling [7]. The most tangible demand for water quality monitoring relates to HABs. The demand for EO information related to HABs pertains to [8]: High temporal and temporal resolution of observation for specific sites or areas; Algal species identification and toxicity information; Observation in all weather conditions; Prediction and observation of HAB formation; and Near Real Time (NRT) warning systems. Although, all of these demands cannot be met through EO and significant research is still required to improve understanding of the causes of HABs. EO technology has the potential of providing timely, cost-effective information that can be of tremendous value to the aquaculture industry. A number of programs are underway, for example ESA Coastwatch [9, 10] and projects co-ordinated by INTESAL [11, 12]. There are several issues affecting HAB monitoring/warning systems, which are also relevant to the wider geo-information market: Integration of in-situ and EO information and associated spatial and temporal resolution issues; Management of time-series data; and Integration of different EO sensors. The supply of geo-information for HABs monitoring presents challenges to the EO industry, but also significant opportunities, in particular for application of MERIS and MODIS imagery. With regards to prospective offshore aquaculture operations, several physical parameters can be measured using optical, thermal and radar sensors. Offshore developments in open waters, where optical properties are less confounded by auxiliary factors, i.e. suspended sediment, makes analysis relatively easier and simplifies requirements for remote sensing algorithms. This assists in the operational delivery of information products. 3.3 Aquaculture Site Selection Given the important impact of the environment on aquaculture facilities, and vice-versa, optimal site selection for an expanding industry is important. In coastal areas, integration of EO data with other spatial, environmental and regulatory information has the potential to become an important component during the site selection processes. Legal criteria often have a spatial dimension, such as proximity to sensitive habitats or other coastal uses. Therefore, the inherent integrative power of geographical information systems (GIS) can provide a framework for utilization of EO data. Further lobbying is required to foster the application of EO data into existing assessment mechanisms, such as environmental impact assessments (EIA) and integrated coastal zone management (ICZM). Future planning and development efforts for offshore aquaculture activities will likely spur the need for oceanographic EO data. Since, certain spectral, spatial and temporal resolution capabilities appear to be more compatible with offshore demands at least when compared with the more stringent requirements for the near-shore operations. EO archives now contain time series of some oceanographic or biological parameters, such as sea surface temperature (SST), waves, and chlorophyll content, which allow for the effective integration of historical data.

4 4. CASE STUDIES 4.1 Shrimp Aquaculture Monitoring, Thailand In this example, the primary objective was to determine the activity of shrimp aquaculture in a coastal area of Thailand. Shrimp ponds are usually above the high tide zone and consist of concrete ponds. There are generally three levels of activity of shrimp ponds: 1) fully operational, aeration devices functioning (Fig. 1); 2) inactive, but filled with water; and 3) inactive and drained of water for cleaning. There have been previous studies with regards to site mapping and detection of shrimp ponds [4]. So far, radar has been used to distinguish ponds, for example using ERS or RADARSAT-1 Fine Mode imagery. Advantages of radar are its all-weather imaging capability and relatively high resolution. However the importance of aerator activity has not been addressed. The latter is of crucial importance for the regulatory authorities for revenue collection. A combination of EO sensors and ground reference data collection has the potential for assisting regular and cost-effective survey. The potential for radar to map shrimp pond aquaculture is clear from Fig. 2, where a Fine mode image and GIS data from the Department of Fisheries (DoF) in Thailand are compared. It is clear that in the southeast corner of the study area, an expansion of farming has occurred since the GIS data was collected. It is unlikely that without complementary multi-temporal or multispectral imagery that automatic feature extraction could be applied, but the radar data has potential for improved efficiency in manual data collection. Concurrent field data were collected with the radar image acquisition in order to provide information on the activity, number and type of pond aerators, and local wind/weather conditions. A close examination of RADARSAT-1 data reveals that water surface disturbance caused by active aeration devices can be distinguished in many cases. The Department of Fisheries in Thailand is still processing a significant part of the field data, but preliminary data reveals that mean pond backscatter is higher for some active ponds. However, even with Fine Mode 1 imagery, spatial resolution is clearly a limiting factor. With upcoming sensors, particularly RADARSAT-2 and TerraSAR-X, which will have sophisticated imaging capabilities and very high spatial resolution, a more rigorous examination of remote monitoring of shrimp pond activity holds considerable promise. Ultimately, the detection of active/inactive shrimp ponds would not necessarily require near real time data delivery and information, which is an important for service development. 4.2 Fisheries Habitat Mapping in the Mekong River Basin Fig. 1. Shrimp pond with active aerators. The objective of the investigation was to map shrimp pond locations and determine whether radar sensitivity to water surface roughness is sufficient to determine activity. Sensitivity is maximized at steep incidence angles [13]. High resolution RADARSAT-1 Fine Mode 1 was selected (HH polarization, incidence angle ca ) for maximum sensitivity to water surface conditions. (Note: The use of Envisat data would enable the assessment of cross-polarisation imagery for increased information content regarding surface water (incidence angle ca. 23 ). However, Envisat ASAR data were not available under the EOMD project, and the desired investigation of cross-polarisation information could not be made.) Natural fish populations in the Mekong Basin are declining as a result of over-fishing, habitat destruction, pollution, and water-management schemes [14]. The impact of uncontrolled development and population growth in the Mekong watershed is of concern to all countries in the region, particularly Cambodia, which relies heavily on the fisheries resources of the Tonle Sap ( Great Lake ) area. A basin-wide approach to fisheries habitat issues, and capture fisheries management in general, is urgently needed in order to ensure sustainable use of the aquatic resources in the Great Lake and Mekong River Basin. Gaps in the current knowledge base pose a serious obstacle to conservation and sustainable management of aquatic resources, especially when considered in light of modern technologies that make possible the overexploitation of the lake's natural products [15]. A critical, yet poorly understood issue is the extent and duration of seasonal flooding in many parts of the

5 Fig. 2. RADARSAT-1 Fine Mode 1 SAR image of shrimp ponds along the northeast coast of Thailand. The image was acquired on July 2, 2004, and overlaid with GIS data provided by the Department of Fisheries in Thailand. (Copyright RADARSAT International, 2004) Mekong River Basin and its relation to fish habitat, fish migration, and fish harvesting. For this region, radar remote sensing is a logical choice as cloud coverage during the monsoon season is a major obstacle for optical sensors. In this example, Envisat Alternating Polarisation and RADARSAT-1 Wide Mode data were compared to determine the boundaries and extent of critical floodplain and wetland habitats. In Fig. 3, the enhanced information content of an Envisat crosspolarised image can be seen compared to like- polarised data, even when the latter is composed of multi-temporal data. The ASAR colour composite image reveals the different radar backscattering behaviors of surface features (mainly vegetation) to the different polarisation configurations of the ASAR instrument. Flood plain vegetation communities provide stronger radar responses in the cross-polarized configuration C-VH, particularly along the edges of waterlogged terrain. These signatures correspond, in part, to the emerging rice crop. In this sense, multi-polarization imagery provides significantly more information than

6 Fig. 3. Single-date Envisat ASAR image (Nov 21, 2003, red: VV, green: VH, blue: VV/VH) and multi-temporal Multi RADARSAT-1 Wide Mode composite image (red: Oct 11, 1999, green: Jan 15, 2000, blue: May 20, 1999) of the Tonle Sap and Great Lake are of Cambodia. the individual single-polarization images of which it is composed. In addition to the main course of the rivers, many waterlogged areas are still in evidence. They are marked by very dark image tone. In order to protect and conserve the fisheries resources, it is essential that local fisheries managers have access to up-to-date information and cost-effective tools for monitoring fish habitat, fishing activities and potential impact sources. EO technology can make a substantial contribution for monitoring fisheries habitats and wetlands in the Mekong Basin. Fig. 4 provides another opportunity to evaluate Envisat Alternating Polarisation data in relation to fishing administrative boundaries in Cambodia and multi-temporal RADARSAT-1 Fine Mode data. Radar imagery, and Envisat ASAR in particular, offers considerable fisheries habitat monitoring capabilities. In the Mekong region, its analysis has helped to improve the mapping of sensitive habitats and the administration of fishing lots and fish reserves. Protection of aquatic habitats will result in

7 Fig. 4. Administrative fishing lot boundary (white) overlaid on A: Envisat ASAR image (as above) and B: RADARSAT-1 Fine Mode composite (red: Oct 4, 1999, green: July 24, 1999, blue: May 13, 1999) in Kampong Tralach, Cambodia. the protection of fisheries resources, which in turn, will help ensure long-term food security in the Mekong Basin. Integration of remote sensing imagery, fisheries information and other environmental and socio-economic data in a GIS format is an effective method for displaying, analyzing and disseminating vital information to all user groups. 5. ACHIEVEMENTS The NEMA project is an on going project that will include implementing prototype EO responses in Phase 2 of the project. Through research, industry meetings, and visits to aquaculture facilities, the following outputs were developed: Identification of market drivers, blockages, and areas of opportunity for EO-based products and services; and Documentation of demand for EO-based products and services by the capture fisheries and aquaculture industry, as well as government regulators. To date, the NEMA project has identified potential opportunities for the integration of satellite technologies into operational activities in the aquaculture and capture fisheries industries. Exploitation of this market requires a comprehensive understanding of the industry. Areas of particular interest where satellite technologies have capacity to make immediate contributions are: Water quality monitoring; Aquaculture site mapping, monitoring, and selection; Regulatory requirements. The NEMA team will be formally presenting the findings of the project and potential fisheries and aquaculture applications to the aquaculture industry at the AquaFlow industry forum. AquaFlow is part of the Aquaculture Europe 2004 Conference, to be held in Barcelona, Spain on October 21, DISCUSSION There is undoubtedly a considerable opportunity for integration of EO technologies into various operational activities within the fisheries sector. However, specific blockages to widespread adoption of EO technologies have been identified through the NEMA project. These blockages can be identified under four general categories: End-users; Products; Service Supply and Distribution; and Benefits and Cost. Limitations of current technologies, level of awareness and lack of integrated services addressing various aspects of aquaculture development, will need to be resolved before widespread adoption of EO technology in the target market will be achieved.

8 A collaborative relationship between the fisheries and aquaculture industries and companies specialising in satellite technologies is required to overcome these blockages and lead to development of enhanced products and services that are not-solely based on EO, but also the integration of a variety of geo-information. An improved understanding of certain aspects of data usage, integration, service development, and delivery mechanisms is also required. With reference to new forms of geo-information (including EO) there is a requirement for: Cost-effective data; Quality standards; and Data that can be easily transferred and integrated with existing operations. Future satellite systems are likely to provide considerable benefits for development of products and services, in particular RADARSAT-2 and TerraSAR-X. 7. REFERENCES 1. FAO, The State of World Fisheries and Aquaculture, FAO, Rome, FAO, Yearbook of fisheries statistics: summary tables 2002, accessed from ftp://ftp.fao.org/fi/stat/summary/default.htm, August Pauly, D. et al. Fishing Down Marine Food Webs, Science, Vol. 279, 6 February Cracknell, A.P., et al. The ABDMAP (Algal Bloom Detection, Monitoring and Prediction) Concerted Action. International Journal of Remote Sensing, Vol. 22(2) , Coastwatch website, accessed from August Morel, A., et al., A Bloom Tale, Coastwatch News, accessed from August INTESAL, Integral Management of the Salmon Industry through Remote Sensing and Oceanographic Techniques of the Latest Generation, accessed from August Rodriguez-Benito et al. Implementation of New Technologies To Monitor Phytoplankton Blooms in the South of Chile, Proceedings of the MERIS User Workshop, Frascati, Italy, November Touzi et al. Ship detection and characterization using polarimetric SAR. Canadian Journal of Remote Sensing, Special issue: RADARSAT-2, Vol. 30(3), , Kottelat, M. and T. Whitten, Freshwater biodiversity in Asia with special reference to fish, World Bank Technical Paper No. 343, Washington, D.C., McDonald, J.A., et al. Plant communities of the Tonle Sap floodplain: Final report for UNESCO, IUCN, Wetlands International, and European Commission, Travaglia, C. et al. Inventory and Monitoring of Shrimp Farms in Sri Lanka by ERS SAR Data, Working Paper No. 1, Environment and Natural Resources Service, FAO, Rome, Italy, Travalgia, C. et al. Mapping Coastal Aquaculture and fisheries Structures by Satellite Imaging Radar (Draft), FAO, Rome, Farming the Deep Blue website, accessed from August Brockmann, C., et al. Operational coastal water quality monitoring: are space borne products an alternative to in-situ measurements - Where are we now? Proceedings of the MERIS User Workshop, Frascati, Italy, November 2003.