Distribution and reproduction of four intertidal crabs (Crustacea, Brachyura) in the Tonda River Estuary, Japan

Abstract

Poss~ble relahons between habitat and hfe history attnbutes of 4 estuarine crabs, Devatonotus tondensis Sakai, Hemigrapsus penlcdlatus (De Haan), Ptychognathus ishu S a k a and Ptychognathus capdhdgitatus Takeda were ~nveshgated Although all species Inhabited ~n t e r h d a l cobble shores in the Tonda k v e r Estuary, central Japan D tondensis dominated the upper reaches, whereas the others were prevalent in the lower reaches AU species grew rapldly after settlement, bred after thelr fust ovennntenng, and had annual breeding cycles Egg size decreased in the order D tondensis, P ~s h , H penlcdlatus, P capdhdgitatus The number of eggs per brood in same-s~zed females decreased in the order P capdhdgitatus, P ishu or H penicdlatus D tondensls Reproduchve effort per year was eshmated to be h g h e s t in D tondensis among the 4 specles The relabvely unstable e n w o n m e n t of the upper reaches, as shown by greater cobble movement, may have favored hlgher reproduchve effort