Variation in <scp> δ ¹³ C </scp> and <scp> δ ¹⁵ N </scp> values of mothers and their calves across southern right whale nursery grounds: The effects of nutritional stress?

Southern right whales (SRW) are capital breeders that use stored energy reserves to sustain themselves and their calves on nursery areas. With successful calving events declining in some SRW populations, it has been hypothesized nutritional stress adult females causes reproductive failure or death of shortly after birth. Here we compared offsets carbon nitrogen isotope values mothers offspring (Δ13Ccalf-cow Δ15Ncalf-cow) among three populations. from Aotearoa New Zealand, with high population growth rates body conditions scores, have negative Δ13Ccalf-cow suggesting utilizing 13C-depleted lipid milk fuel the synthesis nonessential amino acids used build new tissues rapidly grow. In contrast, a significantly positive offset previously reported for Argentina during mass die-off event was be due consuming low content. Patterns Δ15Ncalf-cow were more difficult interpret highlight complexity transfer between mother offspring. When combined similar data collected Brazil mortality year Argentina, hypothesize this approach provides way retrospectively compare condition breeding female across