peat from elsewhere suggests that submergence on Grand Cayman has taken place at a 
similar rate to that in Florida. 
1981 - 1983 
Dunson, W. A., and M. Seidel (1986) Salinity tolerance of estuarine and insular Emydid 
turtles ( Pseudemys nelsoni and Trachemys decussata). J. HerptoL 20(2):237-45. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Pseudemys nelsoni and 
Trachemys decussata inhabit brackish water in mainland areas of extreme southern 
Florida and on Grand Cayman Island. They appear to be intermediate in their salinity 
tolerance between truly freshwater forms and the highly specialized estuarine terrapin 
(Malaclemys ). Unfed P. nelsoni (730 - 1240 g) had especially low rates of mass loss 
(primarily net water loss) in 100% seawater (about 0.4% initial mass day' 1 ). Smaller 
T. decussata (200 - 240 g) had higher values (about 0.8%/day), yet these rates were 
still lower than four values obtained on typical freshwater species (1.8 - 7.6%/day) 
held in 100% seawater. Mean whole body water effluxes in 100% seawater of adult P. 
nelsoni and T. decussata larger than 60 g were low (0.24 - 0.47 mL 100 g' 1 h* 1 ). 
Hatchling T. decussata had much higher rates of water efflux (1.0 mL 100 g' 1 h' 1 ). 
Sodium effluxes in 100% seawater were low (less than 100 nmol 100 g* 1 h' 1 ) in all 
size classes. There was no stimulation in sodium efflux after salt loading in P. nelsoni, 
nor in T. decussata after dehydration in saline solutions. This implies the lack of salt 
glands in these species. Sodium influx in 100% seawater was very low in adult P. 
nelsoni and in T. decussata larger than 200 g. There was a progressive increase in 
sodium influx with declining size in T. decussata, so that hatchlings underwent a 
considerable net uptake of sodium in seawater. Hatchling T. decussata fed fish ad 
libitum were unable to maintain mass or grow when the salinity exceeded 41% 
seawater. Juveniles of about 80 g grew at salinities up to 59% seawater, representing 
a significantly increase in tolerance above that of the hatchlings. Additionally, 80 g 
turtles grew significantly faster in 25% seawater than in freshwater. Large individuals 
(>200 g) of both species tolerated immersion in 100% seawater for prolonged periods 
(at least 10-24 days). Their natural habitats vary seasonally in salinity, but remain 
on average quite dilute due to rainfall. 
1981 - 1986 
Robblee, M. B., and J. T. Tilmant (1989) Distribution, abundance and recruitment of the 
pink shrimp ( Penaeus duorarum) within Florida Bay. Symp. on Florida Bay: A Subtropical 
Lagoon. Miami, FL. June, 1987. Bull. Mar. Sci. . 44(1):522. 
[ABSTRACT ONLY] The Tortugas shrimping grounds were first exploited commercially 
in 1950 prompting intensive study of the early life history of the pink shrimp in the 
shallow near shore waters of South Florida, the primary nursery ground for the 
species. Within the Bay, the pink shrimp is an important source of food for gamefish 
species and wading birds. This paper reports the use of sled net and throw traps to 
study the seasonal and spatial distribution of the pink shrimp in Florida Bay from 1981 
to 1986. Seasonal observations and recruitment studies were concentrated in Johnson 
Key Basin, a high density shrimp area in western Florida Bay. Largest abundance was 
found between fall and winter with peak abundance between September and December. 
The pink shrimp was present throughout the year in Johnson Key Basin and was most 
abundant during fall and winter with peak abundance between September and December. 
During this study, average shrimp size varied seasonally, but was higher in 1986 when 
compared to 1985. During the fall and winter, pink shrimp were most abundant in near¬ 
key habitats in Johnson Key Basin when compared to bank and basin. While very small 
shrimp <9 mm CL were most abundant in near-key habitats, the distribution of shrimp 
size during the winter was similar among habitats. Based on sampling in January 1986, 
pink shrimp generally were most abundant in the west when compared with central and 
265 
