69
Crabs are caught with baited traps. These traps were designed to allow the crab to
enter easily, but to trap it. The catching power of the traps depends on the attractiveness of the bait. Almost all kinds of fish and crustaceans can be used as bait.
Fishermen make their own bait preferences. But the price and availability of bait
affect the preference (Edwards and Early 1978).
Two types of traps are used in crab fishing: (1) Creel, (2) two-Inkwell pot.
Creel consists of rectangular timber base and frames. The frame is covered with
natural or synthetic nets. There is a funnel-shaped opening which allows prey to
enter easily. These opening narrows to prevent the prey from escaping into the end
of the trap. Inkwell pot is round shape. It has a single eye on top. Most fishermen
make their own traps and fix it. But they are made of different materials (Edwards
and Early 1978).
2.2.2.6 Nutritive Composition of Crabs
Chemical composition of crab meat has been studied by several researchers. These
studies have been conducted on different crab species. Table 2.4 shows proximate
composition of crab meat reported by researchers. The table shows that crab meat
with high moisture content is an important source of protein and on the other hand
it is a dietary nutrient with low fat content. In a study, total lipid levels in Paralithodes
camtschaticus, Paralithodes platypus, Chionoecetes opilio, Chionoecetes angulatus
and Chionoecetes japonicus muscles were determined as 0.61, 0.60, 1.57, 0.96 and
0.53, respectively (Latyshev et al. 2009). Total lipid level was reported as 0.5% for
Carcinus maenus (Skonberg and Perkins 2002), 0.75% for Chionoecetes opilio
(Addison et al. 1972), 0.5% (Sidwell et al. 1974) and 2.6% (Otwell et al. 1984) for
P. camtschaticus.
It was determined that the chemical composition of crab varies according to age,
gender, and season. In Carcinus aestuarii, females were found to have high fat and
protein content in gonad and hepatopancreas, and they contained lower moisture and
ash compared to males. The highest fat content was found in winter and spring, while
the lowest in the autumn. Due to the high protein and low-fat content it has been
reported that the best season to consume the crab is autumn (Baklouti et al. 2013).
It is also reported by researchers that crab meat contains n-3 fatty acids at a significant level (Celik et al. 2004). The content of polyunsaturated fatty acid (PUFA)
was found higher in Portunus pelagicus (43.8–45.3%) than in Callinectes sapidus
(39.2–42.8%) (Ozogul et al. 2010). Baboli et al. (2016) found that total n-3 PUFA
ranged between 11.31–20.26% in P. pelagicus. Ramamoorthy et al. (2016) found
the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in
Portunus pelagicus to be 0.89% and 0.63% respectively. On the other hand, EPA
(5.47–7.22%) and DHA (7.27–11.96) contents of the same species (P. pelagicus)
have been reported to be different according to breast meat, claw meat, male and
female. The highest EPA and DHA were determined in the female claw (Baboli
et al. 2016). The ratio of PUFA in total fatty acids in Carcinus maenus harvested
2.2 Crabs
Crabs are caught with baited traps. These traps were designed to allow the crab to
enter easily, but to trap it. The catching power of the traps depends on the attractiveness of the bait. Almost all kinds of fish and crustaceans can be used as bait.
Fishermen make their own bait preferences. But the price and availability of bait
affect the preference (Edwards and Early 1978).
Two types of traps are used in crab fishing: (1) Creel, (2) two-Inkwell pot.
Creel consists of rectangular timber base and frames. The frame is covered with
natural or synthetic nets. There is a funnel-shaped opening which allows prey to
enter easily. These opening narrows to prevent the prey from escaping into the end
of the trap. Inkwell pot is round shape. It has a single eye on top. Most fishermen
make their own traps and fix it. But they are made of different materials (Edwards
and Early 1978).
2.2.2.6 Nutritive Composition of Crabs
Chemical composition of crab meat has been studied by several researchers. These
studies have been conducted on different crab species. Table 2.4 shows proximate
composition of crab meat reported by researchers. The table shows that crab meat
with high moisture content is an important source of protein and on the other hand
it is a dietary nutrient with low fat content. In a study, total lipid levels in Paralithodes
camtschaticus, Paralithodes platypus, Chionoecetes opilio, Chionoecetes angulatus
and Chionoecetes japonicus muscles were determined as 0.61, 0.60, 1.57, 0.96 and
0.53, respectively (Latyshev et al. 2009). Total lipid level was reported as 0.5% for
Carcinus maenus (Skonberg and Perkins 2002), 0.75% for Chionoecetes opilio
(Addison et al. 1972), 0.5% (Sidwell et al. 1974) and 2.6% (Otwell et al. 1984) for
P. camtschaticus.
It was determined that the chemical composition of crab varies according to age,
gender, and season. In Carcinus aestuarii, females were found to have high fat and
protein content in gonad and hepatopancreas, and they contained lower moisture and
ash compared to males. The highest fat content was found in winter and spring, while
the lowest in the autumn. Due to the high protein and low-fat content it has been
reported that the best season to consume the crab is autumn (Baklouti et al. 2013).
It is also reported by researchers that crab meat contains n-3 fatty acids at a significant level (Celik et al. 2004). The content of polyunsaturated fatty acid (PUFA)
was found higher in Portunus pelagicus (43.8–45.3%) than in Callinectes sapidus
(39.2–42.8%) (Ozogul et al. 2010). Baboli et al. (2016) found that total n-3 PUFA
ranged between 11.31–20.26% in P. pelagicus. Ramamoorthy et al. (2016) found
the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in
Portunus pelagicus to be 0.89% and 0.63% respectively. On the other hand, EPA
(5.47–7.22%) and DHA (7.27–11.96) contents of the same species (P. pelagicus)
have been reported to be different according to breast meat, claw meat, male and
female. The highest EPA and DHA were determined in the female claw (Baboli
et al. 2016). The ratio of PUFA in total fatty acids in Carcinus maenus harvested
2.2 Crabs