[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Stone crabs 
are high level carnivores that exhibit sexual dimorphism and support an important 
commercial fishery in southwest Florida. Previous population surveys of stone crabs 
used remote sampling methods (trapping), whereas the information discussed in this 
paper on distribution and abundance, habitat use and reproductive patterns in western 
Florida Bay and the Florida Keys was obtained from quantitative diving surveys. 
Density of stone crabs was highest on the Gulf of Mexico side of the middle Keys and 
lowest on the Atlantic Ocean side of the upper Keys. Mean size of males was largest in 
western Florida Bay and smallest on the Gulf side of the Keys; mean size of females 
was smallest on the nearshore Atlantic side and largest in western Florida Bay and 
offshore on the Atlantic side. Density in the Keys shifted seasonally, being highest on 
the Atlantic side in spring and on the Gulf side in fall. Stone crabs excavate burrows 
under emergent hard substrate (rocks, large sponges, coral heads) or in seagrass 
(Thalassia testudinum) beds. Density was highest in mixed rock/seagrass habitat, 
where stone crabs occur in greater densities in holes under hard substrate than in 
seagrass burrows. Females apparently inhabit rock/seagrass preferentially (average 
male: female ratio 1:2), whereas males apparently prefer mixed rock/sand habitat 
(average ratio 3:1). Seasonal habitat occupancy changed between sexes and differed in 
proportion of habitat types available. On the Gulf side of the Keys, where proportions of 
seagrass and hard substrate were roughly equal, sex ratio shifted between habitats 
during the fall mating season. Males occurred principally in holes under hard substrate 
and females in burrows in adjacent seagrass beds. In western Florida Bay, where hard 
substrate constituted approximately 5% of available habitat, no difference in den 
habitat between sexes was noted, and individuals were distributed randomly. Gravid 
females occurred in disproportionately high numbers under hard substrate in mixed 
rock/seagrass habitat. Mating pairs occurred during spring and fall (principally April 
and October) throughout the study area. Mean size of mating males was significantly 
larger than that of all males, and mean size of mating females was significantly smaller 
than that of all females. Size of mating pairs was not correlated. Percent of spawning 
females was highest in August, when nearly all females were gravid. The population 
structure of stone crabs suggested territoriality and/or habitat dominance related to 
reproductive patterns. Seasonal use of den habitat type changed during mating and 
spawning seasons. Males may have competed for females, and mating habitat use varied 
on a sliding scale, dependent upon relative proportions of habitat types available (e.g., 
emergent hard substrate vs. seagrass). Dens excavated under hard substrate 
presumably require less energy to dig and were quite stable. Preference for that 
habitat by males during mating season and females during spawning season may be 
related to ease of den excavation and/or defense. 
1989 0 
Burke, C. D., and W. D. Bischoff (1989) Chemical differences among the shells of two 
euryhaline species of fossil ostracoda (Crustacea): a preliminary study. Trans. Kansas 
Acad. Sci. . 92(1-2):94-106. 
[ABSTRACT ONLY. DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Microfossils 
were extracted from a Florida Bay sediment core, and brackish and marine 
environments were interpreted on the basis of fossil ostracode and foraminiferid 
assemblages. A total of 48 hand-picked specimens of two species of euryhaline 
ostracodes ( Cyprideis salebrosa and Peratocytheridea setipunctata) were chemically 
analyzed for Ca, Mg, Sr, and Fe concentrations to determine the effect of salinity on 
bulk skeletal chemistry. Results indicate that adult specimens of the two species have 
similar Mg and Sr concentrations, but Fe is more concentrated in the shells of C. 
salebrosa. There are no differences in trace element concentrations in adult specimens 
from brackish or marine sections of the core. Nodose and non-nodose instars of P. 
322 
