Application of Remote Sensing and GIS in Fisheries


Seminararbeit, 2018

30 Seiten


Leseprobe

CONTENT

INTRODUCTION

BASIC CONCEPTS OF REMOTE SENSING

APPLICATIONS OF REMOTE SENSING IN CAPTURE FISHERIES

GEOGRAPHICAL INFORMATION SYSTEM (GIS)

CONCLUSION

REFERENCES

PREFACE

The study material on the “Application of Remote Sensing and GIS in Fisheries” is a humble attempt to convey the physical understanding about the techniques like GIS and Remote sensing to the students from fisheries. Realizing the need for a material describing the application especially in fisheries sector, it was my fervid aspiration to develop a text book.

Even though much care has been given in checking the misprints and mistakes in preparing this material, it is difficult to claim its perfection. It will be thankfully acknowledged in case if any omissions or corrections brought to my notice .The author is also thankful tot the publisher of this book

INTRODUCTION

The Worlds highest producer of fish and fishery products from capture fisheries are identified as major fishing areas by FAO.The countries within the Southeast Asian region considered as a major producer of capture fisheries. In 2019, the world’s fisheries production was amounted to 195.7 million metric tons (MT) of which, 94.6 million MT was from capture fisheries and 101.1 came from aquaculture (SEAFDEC, 2017). Southeast Asian region accounted for about 42.2 million MT that constitute around 22% of the total landing. Among them, Indonesia, the highest producer generated about 20.6 million MT (SEAFDEC, 2017). Considering this scenario, the effective management of the region’s inland and coastal areas is very essential to reinforce the trend of fisheries and aquaculture in geographical region and thereby can ensure food security of peoples within the whole world.

There are existing technologies that would be used for better planning and management of fisheries and aquaculture, e.g. GIS and Remote Sensing technologies. The usage of those technologies is therefore worth exploring, especially in obtaining the required information for formulating appropriate approaches, policies, further as management plans for medium and long-term sustainable utilization of fishery resources and environmental facilities for fisheries and aquaculture. GIS is within the sort of hardware, software, and data that permits any trained staff to update, manipulate, analyze, and display geographically the referred information (Rahel, 2004). Since GIS integrates hardware, software, and data for capturing, managing, analyzing, and displaying all varieties of geographically referenced information, it can provide the unlimited amount of data needed in research (Foote and Lynch, 2015). In fact, GIS has many applications associated with planning, management, transport/logistics, insurance, telecommunications, and business (Maliene et al., 2011). Foote and Lynch (2015) added that the various innovations, like GIS could boost the region’s efforts to enhance fisheries development and management as it links variety of technologies, and thus it emerges as a strong technology.By using this technology, the researchers get assured that the data can be integrated in ways in which it support the traditional sorts of geographical analysis, like map overlay analysis. In addition it is a new kinds of analysis and modeling that are beyond the aptitude of manual methods. Hence GIS can be made use possible to map, model, query, and analyze large quantities of knowledge all held together within one database (Foote and Lynch, 2015). Correspondingly, a technology using satellite or aircraft-based sensor technologies referred to as Remote Sensing, that can be employed to detect and classify objects on earth, including those on the surface, in atmosphere and oceans, supported propagated signals (e.g. electronic radiation). The instruments of Remote Sensing are categorized as passive and active instruments (Earth Observatory, 2018). The Passive instruments will not detect natural energy emitted from observed source, like reflected sunlight. The common passive Remote Sensing instruments include: radiometer, imaging radiometer, spectrometer, spectroradiometer. While active instruments are those accustomed illuminate the objects observed using the radiation they supply. The active remote sensors are radio detection and ranging (radar), scatterometer, light detection and ranging (lidar), and laser altimeter.

Satellite oceanic remote sensing is setting out to play a really important role in India for fishery forecasting, research and management by providing synoptic oceanic measurements. These can then be used for evaluating environmental effects, which ultimately affects the abundance and availability of fish populations. Indian seas have multi species composition. India has a coastline of 8118 kilometer, an EEZ of 2.02 million sqare kilometer and a shelf area of 0.53 million square kilometer (Anon, 2002). it's a well-known incontrovertible fact that changes in ocean conditions greatly influence the natural distribution of fish stocks. Hence the knowledge on variations in ocean conditions is critical to grasp the influence they cause on fish stocks and their distribution. This data will immensely help in formulating the most effective fishery management strategies and developing efficient harvesting methods for fishery resources. Many of the physical features within the ocean like changes in temperature, wind speed, upwelling and eddies directly affect the productivity of the ocean. Because of these changes in particular area within the ocean, the areas are found to be richer in nutrients and phytoplankton. Sequential aggregation of fishes of all levels in area with high organic matter is typically observed in areas of high productivity. Banse & Macclain (1986) earlier reported that seasonal reversing of winds in sea ends up in large-scale change in SST (Sea Surface Temperature). It brings the nutrients to euphotic zone. Hence there's an urgent need in the understanding of influence of ocean variability on fishery resources for timely prediction of productive fishing grounds. Knowledge on ocean variability is obtained by collecting sea truth data with the assistance of vessels by placing equipment attached to buoys. Remote sensing is found to be an effective means of acquiring data as an enormous area of ocean may be covered in a single day. In India majority of the fishing fleet is dominated by small and medium class of vessels. The trouble put by these vessels is restricted up to 120m depth of the sea bottom area. The potential yield of fishery resources in Indian EEZ has been estimated to be 3.92 million tones. Presently only 2.6 million tonnes are exploited leaving most of the oceanic and deeper water resources (Somvanshi, 2002). Commercial fishermen have always been concerned about making the most effective catch for the quantity of your time expended within the search of productive fishing grounds and thanks to the sharp increase within the cost of fuel commercial fishing in deeper waters is becoming economically risky business. to confirm profit by reducing the scouting for productive areas and good catches, it's become necessary to utilize available technological and scientific tools like remote sensing.

BASIC CONCEPTS OF REMOTE SENSING

Human beings are done remote sensing in their day to day life as they collect the features of the objects, through vision, hearing and sense of smell. The collected data can be of many forms viz., variations in the distributions of acoustic wave (e.g. SONAR), variations in force distribution (e.g. gravity meter), variations in electromagnetic energy distributions (e.g., eye) etc.

Remote Sensing (RS) refers to the branch of science that derives information about objects from measurements made at a distance i.e. information is collected without any contact with the object. Conventionally remote sensing deals with the utilization of sunshine i.e. radiation as the medium of interaction. Remote Sensing identifies the earth features by detecting the characteristics electromagnetic wave that's reflected by the planet surface. Every object reflects a little of electromagnetic wave incident depending on its physical properties. In addition to this objects also emit radiation depending upon their temperature & emmisivity. Reflectance pattern at different wave lengths for every object is different. Such a group of characteristics is understood as spectral signature of the item.

Hence the surface parameters can be measured from the electromagnetic radiation (EMR) reflecting or emitting from the surface of Earth in the technology of Remote Sensing. By analyzing the electromagnetic (EM) energy emanating from distant objects of various materials, we can identify and categorize the objects by class or type, substance and spatial distribution.

Remote sensing is not entirely unaccustomed to fishery scientist or to fishermen harvesting marine living resources. It is a very old age practice of inspecting visually to gather information about an object. So the traditional fishermen from ages are using visual kind of remote sensing by elevating themselves above the water surface. The fishermen had using crow’s nests on ships, hot-air balloons, and aircrafts for the watch out or to find the shoal of fishes using their conventional wisdom. The sensor makes use of the optics, usually aided by binoculars or telescopes in observing objects remotely. Visual style of remote sensing is common in many fisheries worldwide. The operation of helicopters from modern Tuna Purse Seiners in finding of schools of fishes and fishing on the high seas are common.

The aircrafts carrying instruments to collecting the oceanographic measurements which supports the research studies in fisheries like identifying areas favorable for fishing or the potential fishing zones are also considered as the a method of remote sensing. Among all the tools, the satellite remote sensing having a satellite fitted with sensor which is employed for viewing the ocean, is treated as the foremost successful remote sensing. The success is principally due to its ability in covering vast area of ocean within the minimum possible time.

Evolution of Indian Satellite Remote Sensing

The use of satellite remote sensing in oceanography started in early 1970’s but expanded considerably by late 1970’s. The satellite with dedicated oceanographic sensors was first launched in 1978 (Laurs & Bucks, 1984). Remote sensing is considered as an important part of Indian Space Programme. The Indian Remote Sensing Satellite Missions was started in 1979 with the launch of Bhaskara-1. Subsequently, Bhaskara-2 was launched in 1981. Their payload consisted with TV cameras and radiometers. the primary generation remote sensing satellites is IRS-IA Linear imaging self-scanning sensors was launched in 1988. It helped to satisfy the growing demand of ocean related information.

The requirement for utilizing space borne remote sensing techniques for ocean related applications IRS-P4 was launched in 1999 (Fig. 1). This satellite is considered as an operational ocean remote sensing satellite containing two sensors. The primary sensor is Ocean Colour Monitor (OCM), with eight spectral bands having revisit capability of two days. The second sensor is Multi-frequency Scanning Micrometer Radiometer (MSMR), operating with four frequencies with global coverage capability. OCM is an 8-channel payload within the visible and near infrared frequencies of the spectrum. The radiometric resolution of the sensor is 12 bits. The sector view of the optics is plus or minus 43° providing a swath of 1420 km from 720 km altitude. The resolution of the sensor is 360 m (Anon, 1999). Department of Space started its initial study on remote sensing of the marine resources using the Advanced Very High Resolution Radiometer (AVHRR) data of National Oceanic and Atmospheric Administration (NOAA) satellite by late 1970s. This research activity continued for over a decade. The knowledge thus acquired has resulted in designing Ocean Colour Monitor (OCM) sensor for IRS P4 and algorithms for our tropical seas. This sensor is capable of retrieving chlorophyll intensity using its 8 wavelength bands. The second sensor on board IRS P4 is Multi-frequency Scanning Microwave Radiometer (MSMR), which is capable of retrieving sea surface temperature and sea surface winds that would give information on the wave patterns using the 8 channels.

Principle of Remote Sensing

Different objects reflect the energy at different amount and different bands which reflects the characteristics of the objects. The properties of the incident energy like intensity, angle of incidence and wavelength also influence the amount of energy reflecting from the objects. The devices that are used to detect the electromagnetic energy reflected or emitted from the objects are called sensors. In Remote Sensing the vehicle carrying the sensors are known as platform (eg. Aircrafts and Satellites).

All materials emit or radiate energy within the range of electromagnetic radiation spectrum.In Remote Sensing Technology, the electromagnetic radiation is expressed generally by its wavelength, λ. Distribution of continuum of energy expressed as a function of wavelength or frequency is known as EMR Spectrum(Fig. 1). So electromagnetic energy can be expressed as E=hcf or E= hc/ λ.

where h is Planck's constant (6.626 x 10ˉ³ Joules-sec), c is a constant that represents the speed of light (3 x 10m/sec), f is frequency in Hertz and λ is the wavelength in micro meters (1µm = 10ˉ6 m).

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Fig. 1 Electromagnetic Radiation Spectrum

Types of remote sensing

1) BASED ON THE SOURCE OF ELECTROMAGNETIC ENERGY

Remote sensing can be classified based on the source of electromagnetic energy as Passive Remote Sensing and Active Remote Sensing.

A. PASSIVE REMOTE SENSING:

In Passive Remote Sensing, the source of energy is that the naturally available source like the Sun. Most of the remote sensing system works with passive mode uses solar energy as the source of Electromagnetic Radiation. The solar energy of specific band width emitting from the target depending on the characteristics of the target. This energy is recorded by the sensors onboard the airborne or space-borne platforms.

An energy band capable of transmitting through the atmosphere without any significant energy loss by the atmospheric interactions are generally used in remote sensing in order to ensure the signal strength at sensors. Any objects having temperature above 0° Kelvin radiates energy and thus Earth also emits radiation as the ambient temperature of the Earth is about 300° Kelvin. This Earth radiance can be measured by using the Passive sensors but the sensors are not much popular as the energy content is very poor.

B. ACTIVE REMOTE SENSING:

In active remote sensing, energy is generated and sent towards the target from the platform. The energy reflects back from the target and are being recorded by the sensors located on the platform. The Microwave Remote Sensing is mostly done through active remote sensing.

II) CLASSIFICATION BASED ON THE ELEVATION OF SENSORS FROM EARTH’S PLATFORM

The remote sensing platforms can be classified based on the elevation of the platform from the Earth surface as Ground Level Remote Sensing, Aerial Remote Sensing and Space borne Remote Sensing. The remote sensing can be done either with Active Sensor and Passive Sensor from these platforms.

The downward or side wise mounted sensors are used to get the images of earth in case of airborne remote sensing. Even though it gives very high spatial resolution images, this can not be used to map a large area. Airborne remote sensing are single time operations. Digital photography, thermal imagery, videography, aerial photography and LiDAR are some of the common airborne remote sensing. The high cost per unit area of coverage and the less coverage area are the major demerits of this airborne remote sensing.

Space borne remote sensing continuously monitors the earth surface and in this remote sensing the sensors are placed on space shuttles. The satellites orbiting Earth like Geostationary and Polar orbiting satellites are used in Space borne remote sensing. Space borne remote sensing covers large area. The unit cost/area of coverage, and automatic or semi automatic computerized analysis are the advantages of space borne remote sensing.The lower resolution of satellite imagery compared to aerial photography is the major disadvantage.

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Fig.2. Classification based on the position of remote sensing platform

(Source: http://www.ilmb.gov.bc.ca/risc/pubs/aquatic/aerialvideo/assets/figure1.gif)

Stages in remote sensing

1) Finding an energy source (Sun or an EMR source placed on platform)
2) Energy transmission from source to object (Scattering and absorption of EMR)
3) Interaction of EMR with target followed emission or reflection
4) Transmission of energy from object to sensor
5) Recording of energy by sensor which can be photographic or non - photographic sensor
6) Transmission of recorded data to the ground stations
7) Image processing of the data & analysis
8) Application

This figure was deleted by the editors due to copyright issues

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Fig. 3. Technique of Remote Sensing (Source: http://geoportal.icimod.org)

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Details

Titel
Application of Remote Sensing and GIS in Fisheries
Autor
Jahr
2018
Seiten
30
Katalognummer
V1173978
ISBN (Buch)
9783346594631
Sprache
Deutsch
Schlagworte
application, remote, sensing, fisheries
Arbeit zitieren
Amrutha R Krishnan (Autor:in), 2018, Application of Remote Sensing and GIS in Fisheries, München, GRIN Verlag, https://www.grin.com/document/1173978

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