日本大眼蟹 英文分类简介

Macrophthalmus japonicus

Classification: Biota > Animalia (Kingdom) > Arthropoda (Phylum) > Crustacea (Subphylum) > Malacostraca (Class) > Eumalacostraca (Subclass) > Eucarida (Superorder) > Decapoda (Order) > Pleocyemata (Suborder) > Brachyura (Infraorder) > Eubrachyura (Section) > Thoracotremata (Subsection) > Ocypodoidea (Superfamily) > Macrophthalmidae (Family) > Macrophthalminae (Subfamily) > Macrophthalmus (Genus) > Macrophthalmus (Mareotis) (Subgenus)

The ocypodid crab Macrophthalmus japonicus is an intertidalmud crab widely distributed in Japan, Korea, NorthChina, Formosa, Singapore and Australia (Sakai 1976). In Japan, this species is one of the most common macrobenthicanimals on many intertidal mudflats (Ono 1965).

The CW of crabs from each sampling station was measuredto the nearest 0.1 mm using hand calipers or a micrometerunder a binocular microscope. Sex and presence of eggs was recorded and most crabs were then released in the areas. To estimate size at maturation for males, thelength of the chela propodus (from the lower end of articulationwith the carpus to the tip of the immovable finger)was measured for males sampled in June to August (N~ 100for each population) and a change in the allometric growthof the chela was determined as described by Simons (1981).Female crabs were classified as immature or mature basedon the size of the smallest ovigerous crabs. Crabs less than5.0 mm CW were difficult to differentiate, and were thereforeclassified as juveniles, assuming an equal sex ratio.Growth patterns were determined by graphical analysis ofthe modal progression of successive size-frequency distributions.Modes in the size-frequency distributions of each sexwere distinguished by plotting cumulative size-frequencieson a probit scale (Cassie 1954). The density of each cohortwas determined in the same manner as growth patterns.Females with recently deposited eggs, sampled in Juneand August

Mortality

In the second year was also higher in the Fukuoka population.Moreover, most females in the Fukuoka populationdied before August in the third year, while most females inthe Amakusa population survived until the end of breeding season