65
more than during the same period in 2017. Indonesia’s share of this volume declined
slightly from 50.1% in 2017 to 44.1% in 2018 (FAO-Globefish 2019b).
2.2.2.3 Some Important Crab Species
Crabs like shrimp and lobster also belong to the Decapoda order. Crabs can be
divided into two main groups as brachyuran crabs (infraorder brachyura) and anomalous crabs (infraorder anomura). Most species of Brachyuran crabs, also called
true crabs, can be easily distinguished by four pairs of well-developed walking legs
from the crabs of the infraorder Anomura, called false crab (Ng 1998).
Crabs are creatures collected in Crustacea class, the Decapoda order and Majidae,
Portunidae and Xanthidae families. The groups belonging to Brachyura infraorder
and called “true crabs” are the most known and studied crabs. There are 4000 species in 26 families.
Swimming Crabs
Carapace hexagonal, transversely ovate to transversely hexagonal, sometimes circular; dorsal surface relatively flat to gently convex, usually ridged or granulose; front
broad, margin usually multi dentate; usually 5–9 teeth on each antero lateral margin,
postero lateral margins usually distinctly converging. Endopodite of second maxillipeds with strongly developed lobe on inner margin. Legs laterally flattened to
varying degrees, last two segments of last pair paddle-like. Male abdominal segments 3–5 completely fused, immovable (Jose 2015). Ten species of interest to fisheries: Arenaeus cribrarius (Lamarck, 1818), Callinectes bocourti A. Milne Edwards,
1879; Callinectes danae Smith, 1869; Callinectes exasperatus (Gerstaecker, 1856);
Callinectes larvatus Ordway, 1863; Callinectes maracaboensis Taissoun, 1969;
Callinectes ornatus Ordway, 1863; Callinectes rathbunae Contreras, 1930;
Callinectes sapidus Rathbun, 1896; Callinectes similis Williams, 1966
(Tavares 1998).
Callinectes sapidus (Rathbun, 1896)
Callinectes name means beautiful swimmer. The blue crab has five pairs of legs.
Unlike other crabs, the last two legs are in the form of flat shovels to provide swimming. The first two legs end with sharp clamps. They use their clamps to catch and
keep their food (Poppke 1977). They also hold them with their clamps to protect
them from damage. If the crab is scared and wants to run away, it breaks or removes
the clamp and improves the new one. The other three legs are used to walk.
Sex is easily understood by the colour of claws in live crabs. In the females, the
colour of the claw is bright red orange. In males, blue and white are the source of
the general blue crab concept. Gender is also understood from the shape of the
abdomen. The lower part of the abdomen, called apron, is T-shaped. The females are
large and circular, while the young females are triangles (Yerlikaya 2002).
2.2 Crabs
more than during the same period in 2017. Indonesia’s share of this volume declined
slightly from 50.1% in 2017 to 44.1% in 2018 (FAO-Globefish 2019b).
2.2.2.3 Some Important Crab Species
Crabs like shrimp and lobster also belong to the Decapoda order. Crabs can be
divided into two main groups as brachyuran crabs (infraorder brachyura) and anomalous crabs (infraorder anomura). Most species of Brachyuran crabs, also called
true crabs, can be easily distinguished by four pairs of well-developed walking legs
from the crabs of the infraorder Anomura, called false crab (Ng 1998).
Crabs are creatures collected in Crustacea class, the Decapoda order and Majidae,
Portunidae and Xanthidae families. The groups belonging to Brachyura infraorder
and called “true crabs” are the most known and studied crabs. There are 4000 species in 26 families.
Swimming Crabs
Carapace hexagonal, transversely ovate to transversely hexagonal, sometimes circular; dorsal surface relatively flat to gently convex, usually ridged or granulose; front
broad, margin usually multi dentate; usually 5–9 teeth on each antero lateral margin,
postero lateral margins usually distinctly converging. Endopodite of second maxillipeds with strongly developed lobe on inner margin. Legs laterally flattened to
varying degrees, last two segments of last pair paddle-like. Male abdominal segments 3–5 completely fused, immovable (Jose 2015). Ten species of interest to fisheries: Arenaeus cribrarius (Lamarck, 1818), Callinectes bocourti A. Milne Edwards,
1879; Callinectes danae Smith, 1869; Callinectes exasperatus (Gerstaecker, 1856);
Callinectes larvatus Ordway, 1863; Callinectes maracaboensis Taissoun, 1969;
Callinectes ornatus Ordway, 1863; Callinectes rathbunae Contreras, 1930;
Callinectes sapidus Rathbun, 1896; Callinectes similis Williams, 1966
(Tavares 1998).
Callinectes sapidus (Rathbun, 1896)
Callinectes name means beautiful swimmer. The blue crab has five pairs of legs.
Unlike other crabs, the last two legs are in the form of flat shovels to provide swimming. The first two legs end with sharp clamps. They use their clamps to catch and
keep their food (Poppke 1977). They also hold them with their clamps to protect
them from damage. If the crab is scared and wants to run away, it breaks or removes
the clamp and improves the new one. The other three legs are used to walk.
Sex is easily understood by the colour of claws in live crabs. In the females, the
colour of the claw is bright red orange. In males, blue and white are the source of
the general blue crab concept. Gender is also understood from the shape of the
abdomen. The lower part of the abdomen, called apron, is T-shaped. The females are
large and circular, while the young females are triangles (Yerlikaya 2002).
2.2 Crabs