EFFECTS OF SALINITY AND STARVATION ON THE LARVAL DEVELOPMENT OF SESARMA-CURACAOENSE DEMAN, 1892, A MANGROVE CRAB WITH ABBREVIATED DEVELOPMENT (DECAPODA, GRAPSIDAE)

The ecology and development of the mangrove crab Sesarma cuaracoense w as studied in Jamaica. Salinity and temperature were measured in the n atural habitat of this crab, and the effects of various salinities, di fferent temperatures, and starvation regimes were studied in the labor atory. The crab inhabits mangrove swamps where salinity and temperatur e ranged from 8-45 ppt and 22.2-39.0 degrees C, respectively, and its larval stages were found in the mangrove area and in an offshore lagoo n. Females produced relatively few (112-980) moderately sized eggs (me an diameter = 0.58 mm after spawning). Development was abbreviated and consisted of 2 swimming, morphologically advanced zoeal stages and 1 megalopa, and the first crab was reached after an average of 13.5-19.3 days when larvae were fed. Development to the first crab stage was co mpleted at salinities ranging from 10-55 ppt. However, a high mortalit y appeared at the extremes of 10 and 55 ppt. When starved from hatchin g, yolk reserves were sufficient for development to the megalopa stage , during which food was required in order to molt to the first crab. S esarma curacaoense had fewer larval stages, the larvae tolerated a wid er range of salinities for development, and showed a higher degree of lecithotrophy than reported for other species of Sesarma outside Jamai ca. Its mode of development is similar to that in the endemic Jamaican species (2 zoeae), and its degree of lecithotrophy is intermediate be tween its semiterrestrial and truly fresh-water and terrestrial relati ves.