470
The severe harassment on right whales by kelp gulls (Rowntree et al. 1998;
Marón et al. 2015), has been suggested to contribute to right whales immigration to
Brazil (Groch et al. 2005). The percentage of living mothers and calves with gull
lesions in Argentina increased from an average of 2% in the 1970s to 99% in the
2000s (Marón et al. 2015), when the rapid increase in the Brazilian population
started. Resightings in Brazil of whales previously photographed off Argentina
(Best et al. 1993, Groch and Rowntree ongoing research), as well observations of
whales with kelp gulls attack marks (Groch, unpublished) support the immigration
hypothesis. Kelp gulls attacks on right whales was first reported in Brazil in early
2000s (Groch 2001), consisting of occasional pecking bouts with no obvious lesions
on the whale’s back. No evidence of increase have been observed so far.
On the other hand, it has been found that right whales from southern Brazil are
isotopically distinct from those from central Argentina, meaning that individuals
from the two areas exploit different feeding grounds (Vighi et al. 2014). The isotopic difference also might indicate that intermingling between the two areas is limited or non-existing, supporting the authors hypothesis of isolation between the
right whales off central Argentina and southern Brazil. The results contradict the
resightings of individuals between these areas, and indicate the occurrence of some
level of structure in the Southwest Atlantic right whale population. The authors suggest the use of two management units for the southern right whale in the Southwest
Atlantic Ocean and independently focused conservation regulations, calculations of
their biological parameters and demographic trends.
The ongoing comparison of the photo-identification catalogs from Brazil and
Argentina will help define the extent of the overlap between both populations, the
direction of movement between these breeding areas, and if the high mortalities off
Argentina can affect the recovery of the right whale population off Brazil.
16.10 The Future
Regardless of the recent rapid increase, the low number of mature females and the
potential threat of coastal anthropogenic activities and habitat degradation right
whales are listed as “endangered” in the List of the Brazilian Threatened Fauna (Ott
et al. 2008; Rocha-Campos and Camara 2011).
The National Action Plan for the Conservation of Aquatic Mammals in Brazil
(Rocha-Campos and Camara 2011) emphasize that more effective measures must be
taken to ensure compliance with legislation, such as adequate supervision of protected
areas and periodic review of legal instruments with the aim to their improvement.
A Conservation Management Plan (CMP) for the southern right whale Southwest
Atlantic population was developed by experts of range states from the International
Whaling Commission (IWC 2013). The overall objective of the CMP is to protect
southern right whale habitat and minimize anthropogenic threats to maximize the
likelihood that southern right whale will recover to healthy levels and recolonize
their historical range.
K. Groch
The severe harassment on right whales by kelp gulls (Rowntree et al. 1998;
Marón et al. 2015), has been suggested to contribute to right whales immigration to
Brazil (Groch et al. 2005). The percentage of living mothers and calves with gull
lesions in Argentina increased from an average of 2% in the 1970s to 99% in the
2000s (Marón et al. 2015), when the rapid increase in the Brazilian population
started. Resightings in Brazil of whales previously photographed off Argentina
(Best et al. 1993, Groch and Rowntree ongoing research), as well observations of
whales with kelp gulls attack marks (Groch, unpublished) support the immigration
hypothesis. Kelp gulls attacks on right whales was first reported in Brazil in early
2000s (Groch 2001), consisting of occasional pecking bouts with no obvious lesions
on the whale’s back. No evidence of increase have been observed so far.
On the other hand, it has been found that right whales from southern Brazil are
isotopically distinct from those from central Argentina, meaning that individuals
from the two areas exploit different feeding grounds (Vighi et al. 2014). The isotopic difference also might indicate that intermingling between the two areas is limited or non-existing, supporting the authors hypothesis of isolation between the
right whales off central Argentina and southern Brazil. The results contradict the
resightings of individuals between these areas, and indicate the occurrence of some
level of structure in the Southwest Atlantic right whale population. The authors suggest the use of two management units for the southern right whale in the Southwest
Atlantic Ocean and independently focused conservation regulations, calculations of
their biological parameters and demographic trends.
The ongoing comparison of the photo-identification catalogs from Brazil and
Argentina will help define the extent of the overlap between both populations, the
direction of movement between these breeding areas, and if the high mortalities off
Argentina can affect the recovery of the right whale population off Brazil.
16.10 The Future
Regardless of the recent rapid increase, the low number of mature females and the
potential threat of coastal anthropogenic activities and habitat degradation right
whales are listed as “endangered” in the List of the Brazilian Threatened Fauna (Ott
et al. 2008; Rocha-Campos and Camara 2011).
The National Action Plan for the Conservation of Aquatic Mammals in Brazil
(Rocha-Campos and Camara 2011) emphasize that more effective measures must be
taken to ensure compliance with legislation, such as adequate supervision of protected
areas and periodic review of legal instruments with the aim to their improvement.
A Conservation Management Plan (CMP) for the southern right whale Southwest
Atlantic population was developed by experts of range states from the International
Whaling Commission (IWC 2013). The overall objective of the CMP is to protect
southern right whale habitat and minimize anthropogenic threats to maximize the
likelihood that southern right whale will recover to healthy levels and recolonize
their historical range.
K. Groch