Potential Fishing Zone

Fishes are known for their nutritional values. It becomes an

important source globally when considered in backdrop of United
Nations' Population Projections data; where many of the countries
believed to see rise, are under-developed and face problems such
as malnutrition. While fishery as a practice of feeding has been
documented since pre-historic times industrial revolution has
changed the scenario. More and more efficient crafts and gears
especially with improved navigational, safety and resource locating
instruments in later half of the 20th century, has put resources
under unprecedented stress. This has resulted in collapse of many
commercially important fisheries. Fishery management gets
further complex - and yet, more important – with primary reports
about climate-change impact over ecosystems have started
coming. At the same time, we have inadequate knowledge of
probable response from species towards such environmental
changes and stress from exploitation. Productivity of oceans
depends on nutrient availability in sun-lit upper waters known as,
euphotic zone. Oceanographic phenomena such as upwelling help
contribute to much of this requirement, by entraining
nutrients above mixed layer depth and in turn, allowing
phytoplankton to sustain food-web with the help of
photosynthesis. Stronger the upwelling, deeper the upper mixed
layer of oceanic water column. This allows colder nutrient rich
waters to surface and resultantly lowering Sea Surface
Temperature (SST). Thus, SST provides handy signature in
detecting upwelling zones with the help of remote-sensing data.
Productive waters may initially attract only planktivorous fishes
but eventually, also to bigger fishes which prey upon them. This is
the very reason how SST was harnessed as a tool towards first of
fishery resource predictions. Commercially important species such
as Tuna, are believed to have temperature specificity. This has
reflected in studies which show positive correlation of specific
temperature range with better hooking rates. Ocean-color
missions have provided more than one dimensions to our
understanding of ecosystem level interactions in ocean. Cooler SST
signature with higher concentration with chlorophyll in compare
to surrounding waters indicates upwelling-induced productivity
and often correlated with higher Catch per Unit Effort (CPUE).
Based on this science, services - often business model - have come
handy; to motivate fishermen leave overexploited near shore
continental-shelf waters and shift focus to open ocean. Such
studies and services are however limited to few countries, often the
developed ones. Presently US, Canada & Japan are known to have
such services available to fishermen commercially. Additionally,
Sri Lanka & Indonesia have similar fishermen support program in
earlier stages of development.
Indian marine fishery is a typical multi-species tropical fishery.
First major rise in annual marine fish production occurred in
1960s with introduction to mechanization of fleet. However, fishery
remained mostly individual affair and till date it has not taken any
corporate format. This had inhibited the fleet from venturing away
from the shore in many parts of the country till early 1990’s when
primary studies started towards locating resources with the help
of satellite. Fishery research organizations with the help of Indian
Space Research Organization (ISRO) laboratories took up primary
studies with encouraging results. Such efforts were utilizing
satellites by US and European countries for SST and Chlorophyll,
respectively. However, towards the end of the decade, India
launched its first satellite for the study of oceans – IRS-P4,
known as Oceansat-1. Oceansat-1 with sensor Ocean Color
Monitor (OCM) on board started providing Chlorophyll data. This
has followed by initiation of Potential Fishing Zone (PFZ) program,
as a no-cost service to Indian fisher community. Initially this
service used SST data from international missions. Eventually
data from more satellite such as MODIS-Aqua & Oceansat-2 were
also incorporated. The service initiated as a one-day delay product
made available weekly-thrice, is now being provided in Near-Real
Time mode every day. Validation experiments carried out in 2000's
shown highly encouraging results, similar to the feedback from
fisher-folk. Today the Indian Marine Fishery Advisory System
(MFAS) is a unique program with decade-plus long experience and
data-archive. For the long term interest towards sustainability, it
is the need of time to understand spatio-temporal distribution of
PFZ (i.e. productive and thermal gradients) within Indian Exclusive
Economic Zone region. In this atlas, we present for the first of its
kind, such analysis with the help of geospatial tools.
Potential Fishing Zone Advisories
The Ministry of Earth Sciences (MoES), earlier known as the
Department of Ocean Development (DOD), initiated Marine
Satellite Information Services (MARSIS) programme in June
1990, to device methods to use the oceanographic data, especially
the satellite data to address the issues involved with the usage of
oceanic resources. One of the objectives of MARSIS was the usage
of remote sensing data and its applications for the management
of coastal oceans and to devise the methods to use the satellite
data to harvest food from sea. At this juncture, the scientists from
marine sciences, remote sensing and fishery science collaborated
to develop a technique that can use the remotely sensed sea
surface temperature (SST) to identify the locations of fish
aggregation. The concerted collaborative efforts of scientists from
Earth Sciences, space and fishery science have resulted in
successful demonstration of the application of satellite derived
data for the demarcation of ‘ Potential Fishing Zone (PFZ)’ as a
proxy to ‘ potential shoals of fish aggregation’ in the Indian
waters

Utilizing the remotely sensed data available from various

satellites, ESSO-Indian National Centre for Ocean Information
Services (INCOIS), provides these advisories to the fishermen on
a daily basis with specific references to 586 fish landing centers
along the Indian coast. This operational service is rendered by
ESSO-INCOIS throughout the year except during the periods of
Marine Fishing ban imposed by Government of India and adverse
sea state conditions such as Cyclones, High Waves, Tsunamis,
etc.

The data on Sea Surface Temperature (SST) and Chlorophyll

retrieved regularly from thermal-infrared channels of NOAA-
AVHRR (USA) and Eumetsat (ESA)’ s Met-Op series satellites
along with optical bands of Oceansat-II (India) and MODIS Aqua
(USA) satellites are used for the identification of Potential Fishing
Zones (PFZ) along the Indian coastline. Divided over 14 sectors -
viz. Gujarat, Maharashtra, Goa, Karnataka, Kerala, South Tamil
Nadu, North Tamil Nadu, South Andhra Pradesh, North Andhra
Pradesh, Orissa, West Bengal, Lakshadweep Islands, Andaman
Islands and Nicobar Islands - the PFZ advisories are generated for
each sector in the form of PFZ Maps and text. The PFZ Maps
contains information on the major landing centers, bathymetry
and the location of PFZ (latitude and longitude information). Due
to the dynamic nature of the ocean the fishing zones identified on
the maps could shift from the marked location. Hence, to guide
the fishermen on the probable shifts in PFZ, the wind speed and
direction information is also incorporated on the PFZ maps. This
information helps the fishermen in locating the PFZ identified in
the maps even if they reach the location after a day.

For the comfort of fishermen, the PFZ maps as well as the PFZ
text are also provided in the native languages of each sector. The
PFZ Text provides the information on location (latitude,
longitude), the depth at PFZ location and the distance and
direction from easily identifiable prominent sites on the coast like
fishing landing centre, light houses.