y de bahi'as costeras alrededor de la isla St. John, mantienen langostas espinosas 
adultas y juveniles. Las observaciones de mas de 15,000 ejemplares de P. argus 
marcados en las poblaciones de estos parques, estan resumidos para proveer 
informacion del desarrollo, mortalidad, reproduccion y movimiento. Los factores que se 
encontraron afectaban mas el desarrollo, fueron las estaciones y danos a los juveniles, 
y el sexo de los adultos. Las poblaciones virgenes proporcionaron estimados directos de 
mortalidad natural. El tamano de la madurez primaria en las problaciones virgenes fue 
mayor que en las poblaciones mas explotadas. Juveniles de P. argus demostraron 
movimientos direccionales extensivo hasta de 200 km, mientras los adultos 
demostraron movimientos restringidos por aproximadamente dos anos. Las devolu- 
ciones de las placas de identificacion durante la temporada de 1977 - 1978 en la Florida 
se dividieron igualmente entre Pescadores deportivos (49%) y comerciales (51%). Sin 
embargo, las devoluciones de las placas de identificacion que fueron situadas directa- 
mente en las nasas o trampas comerciales demostraron que solamente 11% de las 
placas de identificacion en las nasas fueron reportadas. Estas devoluciones demuestran 
que la captura deportiva fue 9% del total en la parte node de los cayos de la Florida si 
todas la placas fueron reportadas. El escape promedio de la langosta de nasas no 
recobradas fue de 1.2% diario durente los 14 dias de caladas. 
1975 - 1988 
Halley, R. B., P. K. Swart, R. E. Dodge, and J. H. Hudson (1994) Decade-scale trend in 
seawater salinity revealed through 5 18 0 analysis of Montastraea annularis annual growth 
bands. Bull. Mar. Sci. . 54(3):670-8. 
Stable oxygen isotope ratios (8 ie O) of coral skeletons are influenced by ambient water 
temperature and by the oxygen isotope ratio in the surrounding seawater, which, in 
turn, is linked to evaporation (salinity) and precipitation. To investigate this 
relationship more thoroughly, we collected hourly temperature data from the Hens and 
Chickens Reef in the Florida Keys between 1975 and 1988 and compared them to the 
6 18 0 of Montastraea annularis skeleton that grew during the same interval. To ensure 
that we obtained the correct oxygen isotopic range in the skeleton we typically sampled 
the coral at a resolution of 20 - 30 samples in one year; in one year we sampled the 
coral at a resolution of 70 samples yr' 1 . Despite our high-resolution sampling, we were 
unable to obtain the full temperature-induced 5 18 0 range in the skeleton. Our data 
suggest that, during the summer, evaporation causes isotopic enrichment in the water, 
partially masking the temperature-induced signal. Our data also show that oxygen 
isotopic composition of seawater at the reef has increased since 1981. This increase 
indicates that salinity has increased slightly during the past decade, perhaps as a result 
of increased evaporation in waters of Florida Bay and the Keys. This phenomenon is 
probably not caused by a decrease in the outflow of freshwater into Florida Bay from 
the Everglades but may be related to the measured deficit in precipitation that has 
occurred over the past decade. 
1976 
Halley, R. B., and R. P. Steinen (1979) Ground water observations on small carbonate 
islands in southern Florida. Guide to Sedimentation for the Drv Tortuqas . R. B. Halley 
(compiler). Southeastern Geol. Soc. Publ. 21. 82-9. 
The ground water of Loggerhead and Cluett Key differs significantly from surrounding 
seawater despite the relatively small size (a few hundred m) of these islands. Climate 
alone does not determine the character of these ground waters; for example, 
Loggerhead Key is underlain by less saline ground water than Cluett Key despite the 
fact that it receives less rainfall. Ground water under small islands such as these is 
formed from a complex variety of variables that affect the hydrology of the islands. 
These variables include topography, sediment character, vegetation, and many more 
220 
