As tags pop off the fish and begin transmitting data, investigators will post the data on the web site. Data to be posted include tagging location and daily light, temperature and depth archives. From these data, students might be able to predict the movements of the fish, by examining charts of bottom topography, images of sea surface temperatures and nautical almanacs (time of sunrise and sunset, etc.). Some knowledge of the temperature preferences and behavior of the fish might be useful in predicting fish movements, and these data might also be found on the internet (e.g. http://www.fishbase.org/). Maps of fish tracks will be provided so that students can check their predictions.

Students and teachers are encouraged to email the project Principal Investigator with questions regarding the project. When tagging commences, we will add daily logs to the web site, and visitors will be able to email the R/V Palmetto with questions. Students will be able to follow the daily cruise track and activities.

Will They Stay, or Will They Go?

We are tagging sharks in Spring, when many coastal species, such as sandbar shark, undergo migrations from warm wintering grounds in the south to summer feeding areas farther north.  As Spring comes to temperate latitudes, day length and plankton productivity increases, and many coastal species migrate to higher latitudes to feed on organisms associated with the Spring plankton bloom.  Oceanic sharks, such as blue sharks, live year-round in ocean waters that are not as subject to seasonal variations in temperature and productivity, and may not undertake annual migrations.  Sharks prefer certain water temperatures, and migrate to stay within those temperatures as water temperatures fluctuate with changing season.  We predict that the sharks we tag will move to areas of high productivity and higher latitude, as Spring and Summer spread northward from South Carolina waters.  As the days get longer and the water warms up, these sharks might move to the north to find food and to stay within their temperature preferences.  Temperature preferences for many sharks can be found at http://www.fishbase.org/, by entering the name of the shark.  By looking at temperature preferences, you might be able to predict where sharks will go.

For example, when we look at blue shark, at http://www.fishbase.org/, we find that they prefer cool waters, from 7 - 21°C, and that they occur in the Atlantic from latitude 66°N down to 55°S.  It is known that they occur from the surface down to 350 m depth.  Sea surface temperature can be measured with satellites, and we might be able to use the satellite images to predict where blue sharks might go to find the water temperatures they prefer.  Sea surface temperature images (SSTs) can be found at many sites, including:

http://www.sstcharts.com/

http://coastwx.com/cgi-bin/makesstSouth.pl?reg=1 - anchor101

Note that interactive, real time SST images are not available on cloudy days, when the satellites cannot “see” the ocean.  Archived images are available from previous years, at the following sites:

http://dcz.gso.uri.edu/avhrr-archive/archive.html

http://www.educnet.education.fr/meteo/ocea_atm/courants/html/coumar24.htm

The latter site contains “instant” images of the North Atlantic SST, that might be useful for predicting where sharks might go.

Sharks and other fishes like to concentrate around thermal fronts, because plankton and other food sources are often found there.  SST images can indicate where warm water meets cooler water, and sharks may migrate along these fronts.  By looking for thermal fronts in SST images, you might be able to predict where sharks will move.

Sharks and other fishes may just drift with the currents.  Oceanographers follow the paths of currents with satellite-tracked drifters.  We can look at the paths of these drifters, and perhaps predict the movements of sharks that passively drift with the currents.  Will they follow the path of satellite-tracked drifters?

When the data are retrieved from the satellite tags, we will know more about the temperature preference and movements of sharks, including vertical and horizontal migration patterns, and we can see how the sharks moved in relation to sea surface temperature, depth, thermal fronts and circulation patterns.