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Japanese mitten crab, Eriocheir japonicus (de Haan), migrates between stream and sea and breeds in shallow coastal areas, exhibiting a catadromous life cycle. This study investigated how the crabs adjust reproductive strategy and migratory behavior to climate fluctuation and what kind of life history strategy individual crabs adopt in a disturbed environment. We conducted a 14-year monitoring study from 1998 to 2011 in Lo-Mei Stream in northern Taiwan. Streamflow and flood timing are controlled by precipitation and typhoons. Abundance of crabs was lower after disturbances by several typhoons and by lower temperatures associated with cold winters in 2006 and 2007. Samples from 2003 showed a reversal in reproductive trends, with increasing size in the same pattern of oocytes, compared to reproductive biology from 1999 to 2005. The life history of E. japonicus can be divided into three stages: spawning migration, growth period, and upstream migration of juveniles to compensate for downstream migration of mature crabs. Reproductively, in E. japonicus the combination of semelparity and synchronous breeding can increase reproductive potential and increase survival in a less disturbed environment at the optimum time. Environmental cues play an important role as major triggers in the persistence of populations. [ABSTRACT FROM AUTHOR]

Orchid Island (Lan-Yu) (22°1′N 121°5′E), Taitung county, a remote island off Taiwan, harbours well developed hard coral communities. These may provide various favourable habitats for their obligate symbionts, gall crabs. Until now, not even a single species of these crabs had been recorded from Orchid Island. For this study, we collected hard corals by SCUBA diving at the coral reefs surrounding Orchid Island. We identified nine species of gall crabs belonging to nine genera. They include Cryptochirus coralliodytes inhabiting Goniastrea australensis; Lithoscaptus paradoxus on G. australensis; Hiroia krempfi on Hydnophora exesa; Neotroglocarcinus hongkongensis on Turbinaria mesenterina and T. peltata; Pseudocryptochirus viridis on T. mesenterina; Dacryomaia edmonsoni on Psammocora contigua; Opecarcinus crescentus on Coscinaraea columna and Pavona venosa; Utinomiella dimorpha on Pocillopora verrucosa; and Hapalocarcinus marsupialis on P. verrucosa. Including the new records from Orchid Island in this study, the established brachyuran crab fauna of Taiwan now stands at 611 species. [ABSTRACT FROM AUTHOR]