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SC/69B/CMP/15
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Resource ID
22058
Access
Open
Document Number
SC/69B/CMP/15
Full Title
The Southwestern Atlantic Southern Right Whale, Eubalaena australis: updated population rate of increase
Author
Enrique A. Crespo, Mariano A. Coscarella, Nicolas Sueyro And Santiago Fern ndez
Authors Summary
This paper reports on aerial surveys conducted to estimate the relative abundance and trend in growth of the southern right whale (Eubalaena australis) population from Pen¡nsula Vald‚s. The number of whales counted tripled from 1999 to 2023. We modelled number of whales, number of calves, number of Solitary Individuals and number of individuals in Breeding Groups using as predictive variables the Year, the Julian day and Julian day2 by means of generalized linear models. The rate of increase decreased from near 8% in 2007 to 0.08% for the total number of whales and from 7.5% in 2007 to 2.99% for number of calves, respectively for 2023. Trends in the rates of increase for total number of whales and number of calves were negative (of -0.576% and -0.342%, respectively). We conclude that whales are still increasing their abundance, while the rate of increase starting to fluctuate near zero for the total number of whales and it continues to be positive for the calves. Additionally, the solitary individuals and the mating groups are decreasing in the area, Differences in the rates of increase of the group types and changes in habitat use are consequence of a density dependence process.
Publisher
IWC
Publication Year
2024