GIS preliminary results

GIS preliminary results from our 2009 and 2010 report
This image shows the observation in the month of August 2010, of mothers and calves. August is the peak season for mothers and calves in Ste Marie, as reported in 2009 and 2010.
Geo-referentiated data was plotted into the public software of Google Earth 2010, compiling different layers, separated by each month in the 2 years collected (2009 and 2010). So, one layer, represents all data of mothers (with their calves) in July 2009 and other, the data set in July 2010. The point taken to represent in the map was the beginning of the contact as noted by field observers. After plotting all data, a perimeter of the outer dots was set up to have a general idea of the location of the observations.
The monthly patterns shows, in both years 2009 and 2010, a shift of mother observations from the Eastern and North eastern (July and August) to the the south-eastern and south. It is important to take into account that the observation could also be a results from the whale watching trips intrinsic factors (sea state, route chosen by tourists, guides or skippers; among the most important ones). Nevertheless we can confirm, based in the 2 years data, that:
- in the month of July mothers and calves start to enter the area of Ste Marie.
- August is the peak season and the outer barrier of Ile aux Nattes seems to be a spot for this type of groups where they tend to congregate. This behavior can be explained because of the shallow waters and calm sea in this area, where mothers use the shallows to protect from bigger males. Mothers also use the calm waters to rest with their youngsters. It seems this area is also the favorite one for training calves to swim into open waters southerly, as they progress they tend to leave the shallow waters, but until then the mother and the calf will return to the safe waters of couple of meter away from the south barrier of Ile aux Nattes.
- Mothers an calves densities shows that this type of groups are within few meters from the coast of Ste Marie (from 200m), demonstrating that within the coastal line of Ste Marie can be considered a vulnerable site for humpback whale calving.
Lazo, R. and Faria, M (2010).

Note: please if you want to use this information cite it as follows
CETAMADA. 2010. – Activities and Results Report for 2009 and 2010.
Chapter GIS: Lazo, R. and Faria, MA
Chapter Socio-environmental activities: Boyer, M. and Faria, MA
Chapter Scientific data: Razafindrakoto, Y., Boyer, M., and Faria, MA

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