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8.1. Summary

is one of the most significant producer of animal protein and protein
requirement of mankind can be fully met with the enormous fishery resources of
world oceans. Most of the problem faced by humans can be connected to energy
use in one way or another. Role of fuel in fishery is important and well
established recently in the scenario of increasing fuel price. However in the
midst of growing concern for rationalization of fisheries management, role of
energy and green house gas emission in global warming and climatic change,
healthy and unhealthy competition among fishermen of different sectors and for
consumer appreciation for low carbon food products, the issue of fuel
consumption needs further exploration.

represents one of the largest cost associated with fishing operation while
actual proportion attributed to fuel varies greatly between fisheries. Being
the most energy intensive fishing system, all these concerns are highest in
trawlers compared to other fishing techniques. India being a developing country
which relies heavily on fishery for livelihood, employment and foreign exchange
earnings the problem in fishery sector affects at most level. Being one among
the most advanced in fishery sector among state of the country Kerala also
follows similar pattern. In the present study, results of the investigations
conducted during 2014-2017 on trawl fishery of Kerala are presented along with an
approach to energy conservation. The content of the thesis is organized into 8

First chapter
of the thesis includes a general introduction, literature review of the topics
covered, rationale and objectives of the study. The objectives set for the
study were; to profile the mechanised trawl fishery of Kerala, to investigate
the growth in trawl fishery of Kerala, to estimate the fuel consumption of
commercial trawlers, to understand the economic performance of mechanised
trawlers in Kerala, to study the drag of trawl nets and evaluation of
efficiency of low drag trawl.

Second chapter
specifies the materials and methods adopted for entire study. It explains areas
covered for the study, methods adopted for data collection, description of
instruments used, research vessel, trawl nets used for experiment, etc.   

Third chapter
is a profile of mechanised trawl fishery of Kerala, in which present status of
technical specifications of trawlers; trawl nets and operation are discussed.
Methodology adopted for profiling is a survey conducted along the entire Kerala
coast starting from Kasargod to Kollam where more than 80% of the mechanised
trawlers are distributed. From the survey it is observed that in Kerala four
category of trawlers are operated; small trawlers, medium trawlers, large
trawlers and very large trawlers. At present small trawlers constitute 20%,
medium trawlers 7%, large trawlers 67% and very large trawlers 3% of the total
trawl fishing fleet of Kerala. One of the major finding is the steep decline in
number of small and medium trawlers which is resulted from fishermen’s
preference toward large and very large trawlers as they perform better in
amount of catch and profit. At present in Kerala, majority of trawlers are
constructed with steel and conduct multiday fishing. Trawlers conduct fishing
throughout the year except trawl ban period. small trawlers are an exception in
which trawlers are made of wood conducting single-day operations exist and they
operate for seven months from August to February. At present in Kerala, most of
the trawlers are coming under the category of large trawlers which are having LOA
16-24 m. Maximum size of trawlers observed at present in the state is 33.5 m. Large
and very large trawlers exclusively use imported engines of higher power.
Indian made engines are popular among small trawlers and medium trawlers. Engine
power of each size class of trawlers was significantly varying among which
small trawlers use 116 – 350 hp, medium trawlers 240 – 427hp,
large trawlers 350 – 495hp and very large trawlers 427 – 550
hp. Four types of trawl nets are popular in the state viz., fish trawls, shrimp
trawls, cephalopod trawls and gastropod trawls. Most common material used for
fabrication of trawl nets are HDPE webbing of varying mesh size and twine size.
Largest trawl net observed in the state have a head rope length of 125.0 m and
the maximum mesh size observed is 10m. ‘V’ form steel otterboards are most
widely used except in small trawlers. Three seasons of fishing exists among
mechanised trawlers of the state viz., one is targeting shrimps, second
targeting finfish and third there with no specific target and operation will be
depending on availability of resources.

chapter is an assessment of temporal growth taken place in mechanised trawl
fishery of Kerala. Trawlers are introduced commercially during 1950s in the
state since then it became popular and constituting major portion of total
fishing fleet of the state and constituting large portion of marine fish
landings. Since 1980s, 5 times increment in number of trawlers is estimated until
2010 but, since 2000 there is no significant growth as a result of fishermen’s
urge to bigger vessels instead of numerous small vessels. While analysing size
of trawlers in the state, it is understood that 5 time growth in LOA
of trawlers occurred since introduction. Proportionately growth in engine power
is also evident and it is estimated to be 55 times since introduction. Design
of trawl nets in the state also showed significant changes. By quantifying the
changes taken place in size it can be concluded as size of trawl nets attained 15
times increment. By analyzing changes in wing end mesh size, shrimp trawls do
not show significant change but in fish trawls, wing end mesh size showed 200
times growth since 1993. Significant growth in size and power of trawlers, size
of trawl net, mesh size and depth of operation are evident, but codend mesh
size is showing no change which is always kept less than the regulations.

Fifth chapter
is fuel consumption, energy efficiency and environmental burdens of mechanised
trawlers of Kerala. Data for the chapter is collected continuously for two
years from June, 2014 to May, 2016 from trawlers operated at Cochin and
Munambam harbours. Quantified data on fuel consumption of each trip of 40
selected trawlers (10 trawlers from each size class) were collected using
pre-tested proforma. From the data, rate of fuel consumption in terms of fuel
consumption per hour, fuel consumption per day, fuel consumption per trip and
fuel consumption per year are estimated for each size class trawlers. In
addition to rate of fuel consumption, fuel efficiency, energy requirement, energy
intensity and carbon emission of all size class of trawlers were also
quantified. Hence from the chapter it is evident that rate of fuel consumption
is in linear relationship with length overall of trawlers which ranged from
0.01 to 0.15 million litres in trawlers annually. By analyzing fuel consumption
rate of similar sized single-day and multi-day trawlers, it is understood that
single-day trawlers consume 57% less fuel compared to multi-day trawlers. Fuel
consumption per hour of trawlers ranged from 7.5 to 48.5 litres in various
length classes. On an average Kerala trawl fishery consumed 165.3 million
litres of fuel annually during the period of study at an average rate of 0.96
kg per kg of fish landed which ranged from 0.28 to 3.45 kg. Energy required of mechanised
trawlers in the state in the form of fossil fuel ranged from 18.4 to 110.43 GJ
of energy in a year exclusively for operation. Energy intensity of mechanised
trawlers in the state on an average can be estimated to be as 36.25 GJ per
kilogram of fish landed. Regarding carbon emission, Kerala trawl fishery
released 0.45 million tonnes of carbon in a year exclusively through fuel use
at the rate of 2.24 kg CO2 per kg of fish landed during the period
of study. Comparing different length class of trawlers, it is understood that
rate of carbon emission is least in very large trawlers (1.87 kg per kg of
fish) followed by medium trawlers (1.98 kg per kg of fish), large trawlers (2.6
kg per kg of fish), small trawlers (single-day) (2.73 kg per kg of fish ) and
small trawlers (multi-day) (4.03 kg per kg of fish).

Sixth chapter,
economic performance of mechanised trawlers in Kerala delineates capital
investment, costs expended annually and its economic efficiency of trawlers in
Kerala. Data were collected through a survey conducted among mechanised
trawlers operated in three districts Kollam, Ernakulam and Kozhikode. Centres
selected were Neendakara, Sakthikulangara, Cohin, Munambam, Beypore, Puthiyapa
and Chombal. Additionally data were also collected from trawlers of Cochin and
munambam harbours which were selected for studying fuel consumption. Through
the study it is understood that capital investment for mechanised trawlers in
Kerala ranged from 0.45 to 13.74 million rupees. Cost or expenditure of
trawlers are two types; fixed cost and operational cost (variable cost). Fixed
cost is estimated on annual basis which includes interest on capital, cost of
insurance and cost of depreciation cost. It varied from 0.3 to 2.5 million
rupees in different length class of trawlers. Second category of cost which is
most considered in trawl fishery is operational cost in which cost of fuel,
wages, daily allowance and food, cost of ice and baskets, cost of lubrication
oil, landing charges, auction charges, repair and maintenance and miscellaneous
charges are included. It ranged from 1.21 to 14.52 million rupees in trawlers
of the state and contribution of fuel cost to the operational cost of trawlers
ranged from 47 to 55% with an average of 51% and from the revenue obtained, 26
to 37% is spent towards fuel cost. By analyzing the profit very large trawlers
found to be efficient however time medium trawlers found to be more efficient
by analysing economic efficiency indicators.  

literature review and studies on fuel consumption of mechanised trawlers, need
for fuel conservation in fishing especially trawling have emerged. Low drag
trawls found to be an optimum technology to reduce fuel use of trawlers without
much effort. On these background, seventh
chapter describes the efficiency of low drag trawl in fuel consumption and
fish capturing. A low drag trawl was designed by incorporating reduced twine
size which will be beneficial in reducing twine surface area and reduced drag.
But when using thinner twines, it should be assured that the twines are capable
of providing equal or more strength than conventional twines. To provide the
optimum strength, at lower twine size, UHMWPE is selected as suitable material.
The evaluation was done through experimental fishing trials conducted from
ICAR-CIFT departmental vessel, Matsyakumari II using two trawl nets of 24.0 m
head rope length one fabricated with UHMWPE webbing and the second with HDPE
webbing. The results showed that usage of UHMWPE material is beneficial in
reducing 36% drag which will be beneficial to 23% savings in fuel. While
reducing fuel consumption, UHMWPE trawl also showed improvement in fish
capturing, there was 2.5% increment in catch per unit towing time and 52%
increment in catch per unit litre of fuel used. Through the experiments an
assessment of impact of operational parameters on drag and impact of drag on
fuel consumption of trawlers were also carried out in which it is estimated
that 6.3% decrease in towing speed makes 1% decrease in drag and 1.9% reduction
in drag of trawl nets make 1% reduction in fuel consumption of trawlers.

chapter of the thesis is summary and recommendations in which summary of all
chapters and some recommendations based on findings of the thesis are given.

8.2. Recommendations

Number, size and
engine power of existing trawlers and size of trawl net found to be very high
from the optimum capacity and strict regulations on the same is needed.

Codend mesh size
found to be smaller at every region which results in huge bycatch and crucial
monitoring is needed.

As rate of fuel
consumption fund to be very high compared to previous studies, which is a
result of the excess engine power and in-efficiency of engine which should be

trawling exists in every districts which is having no regulations in mesh size
or fishing time and is less noticed, regulations in mesh size and fishing time
is necessary in the same.

feasibility of UHMWPE webbing is to be studied on a commercial level.

As low drag
trawls are found to make fuel saving, commercialization is needed.