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International Journal of Marine Science 2015, Vol.5, No.7, 1-4
http://ijms.biopublisher.ca
1
Research Report Open Access
Economic performance efficiency of gillnet based on mesh size and net color
Fatemeh Radfar
1
, Houshang Ansari
2
, Mohammad Hasan Gerami
3,4
, Mehdi Dastbaz
1
1. Gorgan University of Agricultural and Natural Resources, Gorgan Iran
2. Iranian Fisheries Research Organization, South Iran Aquaculture Research Center, Ahvaz, Iran
3. Gonbad Kavous University, Gonbad Kavous Iran
4. Young Researchers & Elite Club, Shiraz Branch of Islamic Azad University, Shiraz, Iran
Corresponding author email
International Journal of Marine Science, 2015, Vol.5, No.7 doi: 10.5376/ijms.2015.05.0007
Received: 10 Dec., 2014
Accepted: 25 Jan., 2015
Published: 04 Feb., 2015
Copyright
©
2015
Radfar et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Radfar et al., 2015, Economic performance efficiency of gillnet based on mesh size and net color, International Journal of Marine Science, Vol.5, No.7 1
-
4 (doi:
Abstract
Increasing efficiency of fishing is one of major goals of fisheries researchers. The aim of this study was to evaluate the
efficiency of gillnet with three different colors of green, blue and white, and three different mesh size 3.75, 6 and 10 cm (STR) in
Khuzestan waters. Data were recorded from three fishing harbor Arvand, Choobedeh of Abadan and Khoramshahr during 2008-2009.
Simpson diversity and economic diversity index were used to analyze data. Results showed that economical index of green net was
more than the other colors. In addition, the efficiency of 10 cm (STR) mesh size was higher than two treatments. In conclusion,
results demonstrated that using green net with 10 cm (STR) mesh size is more economical.
Keywords
Gillnet; Mesh size; Color; Efficiency
Introduction
Optimizing and improving efficiency of fishing gears
is one of the important issues that fisheries and
environmental sciences emphasize to. Gillnet is a wall
structure of net that lied in water column and catch the
fish school. Less requirements of gillnet fishing rather
than other fishing methods (like trawl and purse seine)
made it as a popular method in Iran (Dastbaz, 2011).
Scombridae, Clupeidae, Carcharhinidae, Carangidae
and
Rachycentridae
are the main groups of pelagic
fish that found in catch composition of gillnet (Gerami
and Dastbaz, 2013). There are 740 fishing vessels and
more than 1200 fishing boats using gillnet (pelagic
and bottom) in Khouzestan waters.
36 species (70% total catch) of gillnet catch are
bycatch (Ansari, 2013). Therefore it is necessary to
improve efficiency of gillnet for reducing bycatch.
Several studies about catch composition of gillnet
were done in Persian Gulf (Dastbaz, 2011; Parsa et
al., 2014). Efficiency of stable gillnet with 170 cm
(STR) mesh size due to reduce catching Persian
sturgeon (
Acipenser
persicus
) was also investigate
(Behrooz Khoshgalb et.al, 2010). Determining
standard mesh size of gillnet for Yellowfin tuna
(
Thunnus albacares
) in Oman Sea was another
investigation done by Hosseini (2003).
The aim of present survey is to evaluate the efficiency
of gillnet according to mesh size and color. Net color
is one of the important factor affecting gillnet catch.
The more net color fading in water the more out of
sight of fish, then the operation of this net is
successful. Fish are myopic animal and they can see
10 m at a 20 m depth from the surface (Balık and
Çubuk, 2001). This creatures have color detection
ability, thus different net color can affect catch
(Backiel and Welcomme, 1980). Gillnets are used in
various color in and fishermen don’t have any
knowledge of its great function, so the present tries to
introduce basic information of gillnet with three
different colors and mesh size and state best
economical one.
1 Materials and Methods
Gillnets catch data were recorded from fishing vessels
of three harbors Arvand, Choobedeh of Abadan and
Khoramshahr (Khouzestan Province, Iran) during
2008-2009 in Khouzestan waters, Persian Gulf (Figure
1). Because of different sunlight that radiate to water
during a day, we try to assimilate hanging up
(remaining) and setting time of net. Thus data were
classified and outlined data were removed. Simpson
and economic diversity indexes were used to
analyzing the efficiency of nets.