CZS Sarasota Dolphin Program

Friday, April 4, 2008

Franciscana Dolphins Tracking Day #32

The animals remain in Bahia San Blas, with Kure and Tunken remaining in a very tight pair, and the other two seemingly less tight. Dive patterns among the three dolphins with TDRs (Kure, Tunken, Nahuel) are very consistent. Based on preliminary analyses of more than 80,000 dive records, common dives are to 5-15 meters, and last 60-90 seconds. Rarely, dives appear to have lasted 4-5 minutes or more. Maximum dive depths reach the bottom in the deepest waters of the area, 30-35 meters.

Thursday, April 3, 2008

Franciscana Dolphins Tracking Day #31

The dolphins continue their patterns in Bahia San Blas. Kure and Tunken moved outside the mouth, and remain together. Earlier, they were in very close proximity to Nahuel deep inside the bay.

Wednesday, April 2, 2008

Franciscana Dolphins Tracking Day #30

The patterns continue. Both pairs of animals continue to move through Bahia San Blas.

Tuesday, April 1, 2008

Franciscana Dolphins Tracking Day #29

The dolphins remain in or just outside of Bahia San Blas. Although the pairs seem pretty tight, there was at least one occasion when Kona and Nahuel moved through the channel separately.

Monday, March 31, 2008

Franciscan Dolphins Tracking Day #28

Both sets of animals remain in Bahia San Blas, and although their final locations for the day could not indicate they were together (because they were at different times), they were together for much if not all of the period prior to the end of the day's transmission session.

Science as it Happens!

Ranging Patterns and Habitat Use of Franciscana Dolphins off Argentina: 2008

In March 2008, Chicago Zoological Society conservation scientists Randall Wells, Jason Allen, and Aaron Barleycorn returned to Bahia San Blas, Argentina, to work with Pablo Bordino and his dedicated team of students, colleagues, and fishermen, and a veterinary team from Disney’s Animal Programs, to conduct additional satellite-linked tagging of franciscana dolphins. Building on the tagging and tracking work during 2007 that indicated a high degree of residency to Bahia San Blas over periods as long as six months, the next phase of the project was designed to address specific questions about:

1) what part of the water column the dolphins use – if the dolphins show preference for water of particular depths, then fishermen might be able to set their nets at different depths in order to avoid the dolphins. Up to three satellite-linked transmitters with time-depth recorders (TDRs) will provide information on the depths of dives as well as locations.

2) developing correction factors for aerial and boat surveys for dolphin abundance that take into account the dive patterns of the animals – the TDRs provide information on dive durations and time spent at specific depths where the animals might be visible to scientists.

3) social patterns – deploying tags with identical duty cycles, it is possible to determine if the animals exhibit a stable or fluid pattern of social associations, through examination of their location data to see if they remain together or separate. In addition to the location data from the TDR tags, as many as 5 location-only tags may be deployed. Genetic samples collected during the tagging process will allow determination of relatedness of dolphins caught together.

The first two transmitters, both TDRs, were deployed on a juvenile male (#42483) and an adult female (#42485) on March 4, 2008. As data are received from these and subsequent transmitters, they will be displayed on this site, as maps showing dolphin locations.

The radio transmitter ("tag") was specially designed for dolphins and weighs only 15 grams. The expected battery life is approximately four weeks, and the tag naturally falls off some time later.

Major support for this project was provided by the Chicago Zoological Society and Disney’s Animal Programs, with tags and tag data processing assistance provided by Dolphin Quest.