Floridas freshwater stingrays:

1
Floridas freshwater stingrays Atlantic
stingrays of the St. Johns River.
Jim Gelsleichter Center for Shark Research
2
Freshwater elasmobranchs diversity and
distribution
Sharks
Rays
3
The St. Johns River the river of lakes

• Ancient intracoastal lagoon system
• Longest river in FL (310 miles)
• Width varies (2 miles)
• Slow moving, poor flushing
• Commercially/recreationally impt.

4
The Atlantic stingray Dasyatis sabina

• Most abundant elasmobranch on SE U.S. coast
• Small (

5
(No Transcript)
6
Differences in osmoregulation
WATER SALT
WATER
Low urea
urea
Marine elasmobranch
Euryhaline elasmobranch (bull shark)
No urea
Low urea
Obligate freshwater ray (potamotrygonid)
D. sabina in St. Johns River
7
Ecological differences

• predators
• prey
• parasites

8
Goals of present study Role of calcitonin in
reproduction and development of elasmobranchs
Calcitonin 32 amino acid peptide hormone
9
Role of calcitonin in D. sabina.
Objective Investigate calcitonin bioactivity in
Atlantic stingrays, Dasyatis sabina, throughout
reproduction

• Specific objectives
• Evaluate changes in UBG development/activity
• Re-evaluate serum CT profiles in male and female
  stingrays
• Immunolocalization of CT and CT-binding sites in
  tissues

• Why stingrays?
• largest UBG of all elasmobranchs
• highest serum CT
• availability of dasyatid CT

10
Reproduction in D. sabina
aplacental viviparity with uterolactation

• Reproductive cycle of D. sabina
• annual cycle
• 7-month male sperm storage/mating
• 1-4 pups/litter
• 4-month gestation

11
Animal collection
Lake Jesup
12
Sampling procedures
13
(No Transcript)
14
(No Transcript)