(Everglades Mullet Wrapper)
Sawfish Research
Continued Success Locating & Tagging Juvenile Smalltooth Sawfish
by Dana M. Bethea
NOAA Fisheries Panama City Laboratory Panama City, FL
The cooperative acoustic tagging project between the Florida State
University's Coastal and Marine Laboratory and the NOAA Fisheries
Service Panama City Laboratory has had much success in 2011.
Researchers on the Smalltooth Sawfish Abundance Survey have
captured and tagged 5 neonate and 20 small juvenile animals this year
in the Ten Thousand Islands Backcountry Region. The abundance
survey has been funded through 2012.
The acoustic tagging project is slated to continue through
November 2011 in the backcountry waters of Everglades National
Park from Turner River to Lopez River and inside Chokoloskee Bay.
During this project, immature (less than 150 cm or 59 in) smalltooth
sawfish will be fitted with acoustic transmitters in order to study
movement patterns and habitat utilization. The tag is attached to the
first dorsal fin.
In March, five small juvenile animals were caught in Everglades
National Park. They were all under 30 inches and too small to tag
with an acoustic transmitter. Smalltooth sawfish grow very fast in
their first year of life. Data suggests that they grow up to 4 inches in
one month. In April, four small juvenile smalltooth sawfish (all over
34 inches) were caught tagged in Mud Bay, Everglades National
Park. In May, four more small juveniles (all over 35 inches) were
captured in the park – 1 in Mud Bay and 3 near the boat ramp at
Outdoor Resorts. In June, 2 small juveniles (both over 37 inches)
were caught and tagged on the west-side of Hwy-29. In July, six
small juveniles (all over 43 inches) were captured and tagged on the
west-side of Hwy-29. As of July 30, there were 10 juvenile
smalltooth sawfish tagged with acoustic tags swimming throughout
the array. There are plans tag up to 10 more small juveniles this
summer and early fall.
The acoustic station array was recently expanded from 16 to 32
receivers. Acoustic stations, which record the acoustic tag number as
the individual animal swims by, are now be anchored on the east and
west sides of Chokoloskee Island and along Turner River, Hurdles
Creek, Mud Bay, Cross Bays, Crooked Creek, and the Lopez River.
These stations consist of an acoustic receiver attached to a cinderblock
and are marked with a single white float. Please stay clear of all
acoustic stations. A map of station locations is located at the boat
ramp at Outdoor Resorts on Chokoloskee Island.
In addition to using the acoustic array to monitor movements, a
graduate student from the Florida State University has been actively
tracking animals. Each acoustic tag emits an ultrasonic "ping" at a
unique frequency. Using a hydrophone attached to a receiver and a
kayak, she has been able to actively track (or follow) 5 animals for up
to 28 hours. On her most recent trip in July, she actively tracked one
animal over a 4 days span from July 27-30. Tracking animals in this
manner adds fine-scale movement data to the larger-scale presenceabsence
data collected by the acoustic array.
Researchers with the Smalltooth Sawfish Abundance Survey will
be back in Everglades City August 21-28.
If you see or encounter a smalltooth sawfish, please contact the
National Sawfish Encounter Database at (352) 392-2360. Be prepared
to give the date, time, and location of the encounter. Input and
cooperation from the general public is greatly valued.
This research follows permits EVER-2011-SCI-0010 and ESA-
13330 and is funded through the NOAA Fisheries Service Southeast
Regional Office in St. Petersburg, FL.
http://www.evergladesmulletrapper.com/pdfs/full_issue.pdf
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