Panulirus Brunneiflagellum

''Panulirus brunneiflagellum'' is a species of spiny lobster that lives around the Ogasawara Group (Bonin Islands) of southern Japan. Its members were previously included in '' P. japonicus'', although it may be more closely related to '' P. femoristriga''. It has been fished for more than 150 years by Japanese fishermen, who call the species ''aka-ebi''. It differs from related species by the lack of banding along the flagella of the first pair of antennae.

Distribution

The Ogasawara Group, or Bonin Islands, are an outlying archipelago of Japan in the western Pacific Ocean, on the Izu–Bonin–Mariana Arc. They lie around south of Tokyo, and north of Saipan in the Mariana Islands. ''P. brunneiflagellum'' is the dominant ''Panulirus'' species around the southern islands in the group, but has also been recorded from Hachijo Island, at the north end of the Izu Ridge, from the Japanese mainland.

Description

''Panulirus brunneiflagellum'' is a typical spiny lobster. Adults vary in carapace length in the range . The chief distinction between ''P. brunneiflagellum'' and related species of spiny lobster is in the colouration of the antennules (first antennae). In ''P. brunneiflagellum'', the bases of the antennules are blackish purple, with white spots around the joints. The flagella are brownish, with no bands of colour. ''P. longipes bispinosus'' has paler antennules, and the flagella have four white bands across them.

Taxonomy

In 1991, Hideo Sekiguchi reported the presence of two distinct forms of '' Panulirus femoristriga'' in Japanese waters. These were known to native fishermen as ''aka-ebi'' (literally "brown whisker") and ''shirahige-ebi'' (literally "white-banded whisker"). A third form is known as ''shironuke-ebi''.

In 2005, Ray W. George assigned ''P. brunneiflagellum'' to an Indo-Pacific group within the genus ''Panulirus'', which also contained '' P. japonicus'', '' P. cygnus'', '' P. marginatus'' and '' P. pascuensis''. It was thought to have split from ''P. japonicus'' as a result of volcanic activity, either during the formation of the West Mariana fore-arc () or during the extension of the Ogasawara Chain (). Subsequent molecular analyses have suggested that its sister species may instead by ''P. femoristriga''.

Ecology

''Panulirus brunneiflagellum'' lives in clear, tropical waters at depths of up to , where temperatures are in the range . It lives in open caves, sometimes in association with '' P. longipes bispinosus'', but usually near the entrance, whereas ''P. l. bispinosus'' shelters in the depths of the caves.

Fishery

Japanese settlers colonised the Ogasawara Group in the 1860s, and began fishing ''P. brunneiflagellum'' soon after arriving. The fishery uses rectangular steel lobster traps covered in plastic mesh, roughly 1.0 × 0.5 × 0.5 metres in size. The traps are set daily at depths of , and baited with fresh fish. Up to 24 boats are involved, 20 from Chichi-jima and up to four from Haha-jima. Between them, they catch per year, of which 98% is ''P. brunneiflagellum'' (the remainder being ''P. longipes bispinosus'' and occasional '' P. penicillatus''); Most of the catch is frozen and dispatched to Tokyo. A closed season is in force in June, July and August, to protect ovigerous (egg-bearing) females. In the absence of any detailed information, ''P. brunneiflagellum'' is listed as ''Data Deficient'' on the IUCN Red List.

References

External links

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{{Taxonbar, from=Q5501333

Achelata
Crustaceans of the Pacific Ocean
Crustaceans of Japan
Crustaceans described in 2005