Try your luck and help scientists: match your humpback whale with CETAMADA´s free database!

En ligne le 13 août 2010 | 61 commentaires

Methods for reliably identifying and monitoring individuals are critically important to understanding the behavior of animals. Naturally occurring distinctive features have proven particularly useful for studies of free-ranging populations of marine mammals, especially in those cases where artificial marking could potentially harm animals or bias behavioral data collected. Since its first use in the 1970s photo-identification has emerged as a dependable, non-invasive technique for measuring social grouping, movements, residency, abundance, and life history of many cetacean species. It has proven particularly useful for examining associations between individuals at different spatial and temporal scales. Most photo-identification studies of dolphins and porpoises rely on nicks and cuts in the dorsal fin that provides long-lasting, individually unique markings; somebody scars and pigmentation patterns also persist over many years and can be used for identification.
Many techniques have been developed to standardize and facilitate comparison of photographic records including tracing of dorsal fins onto standardized sheets and calculation of parameters such as the dorsal ratio. With the advent of computer-aided photo-identification database sorting and semi automated photographic matching techniques, catalogs of distinctively marked individuals are increasingly being maintained in a digitized format.
Humpback whales are exceptional and among them each individual is unique. As our fingerprints are specific to each person, flukes (the internal area of the caudal fin or tail) are the main feature used up to day to identify individuals; further studies have been done to use as well dorsal fins. Fortunately, as humpbacks descend deeper, they arch their back steeply and often raise their flukes or tail into the air. If positioned correctly, you can snap a photo of the ventral side (underside) of their flukes as they are diving. This photo can then be used to identify each animal. A close look at a good fluke photo can reveal specific markings that are unique to each whale.
In order to keep track of the population of humpback whales (Megaptera novaeangliae) that comes around Ste Marie during the winter to breed and mate, fluke photographs are constantly being taken all through the season (June 15 to September 30). These photographs are assessed by eye and assigned rank values on a 1 to 5, white to black scale, based on the proportion of white and black coloration present on the flukes.
Photo identification can be used to answer some of the questions on the following subjects:
Migration and Movements
Breeding Site Fidelity
Kin/Social Relationships
Age/Longevity
Reproductive Success
Age of First Successful Reproduction
Population Estimates

Cétamada has been putting lots of efforts to set up the new free database in order to help understand the subjects below. Whales migrate for more than over 5.000km passing coast of many countries and they do not distinguish between political frontiers, neither from different scientific NGOs and projects, that is why it is so important to provide free data base in order to share the information gather around their migration areas. We hope many other scientific associations would follow this initiative and C{etamada hopes as well the active participation of many people around the world that have and will enjoy the pleasure of taking pictures of these wonderful animals and help us understand better their behaviors.
We invite you to try luck with the following individuals and if you got a match please do not hesitate to contact us, we will be happy to receive your picture and details.
NOTE:
When matching fluke photos, there are some tricks to make it simpler.
• Remember that coloration and markings may be more or less pronounced depending on the lighting and angle.
• Also keep in mind that some markings can be acquired in the time between taking each photo.
• If you are taken pictures of individuals please keep track of the exact place were the picture was taken (GPS point).
• When possible, use the trailing edge to confirm a fluke match. This tends to remain fairly stable through the whale’s life, and thus, is a reliable tool in identification.
• If you have access to photo editing software, there are some tools that can help “bring out” details and markings on a fluke that may otherwise be difficult to see. First, rotate the image so the fluke in the image is not slanted in the frame. Next, crop the photo so the fluke is the majority of the frame. You can alter the exposure of the photo by increasing and decreasing the gamma and contrast. It is not advisable to use the other exposure options, as those editing options are more dramatic and could make some markings “appear” that are not actually there.
• If possible, use photos that are the same size. This can be done by cropping your photo to a designated size.
• Be sure to always keep a copy of the original photo in case you want to go back to it.

Mettre une réponse

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>