Producción CyT
Seabird attacks contribute to calf mortality in a whale population
Articulo
Autoría:
Piotto, M ; BARBERÁ, IVÁN ; Sironi, M ; Rowntree, VJ ; Uhart, MM ; Agrelo, M ; Fernández Ajó, AA ; Seger, J ; Marón, CFFecha:
2024Editorial y Lugar de Edición:
INTER-RESEARCHRevista:
MARINE ECOLOGY PROGRESS SERIES, vol. 746 (pp. 1-16) INTER-RESEARCHResumen *
Reports of seabirds attacking marinemammals have become frequent in the 2000s. South-ern right whales Eubalaena australis off PenínsulaValdés (PV), Argentina, have suffered the effects ofmicropredation by kelp gulls Larus dominicanus sinceat least the 1970s. During 2003–2013, this populationexperienced 9 yr of unprecedented high calf mortal-ity. Using a 25 yr dataset (1995–2019) of focal followsof gull–whale interactions, we studied long-termchanges in gull attack intensity (attacks h –1 ) and fre-quency, and explored whether they influenced calfmortality. We also asked whether calf mortality wasaffected by prey density at maternal feeding groundsduring gestation. Applying Bayesian models, we foundthat the intensity and frequency of attacks increasedsignificantly from 1995 to the 2000s, and that in 2004–2019, calves received 2.85 times as many attacks asdid mothers. Moreover, attacks significantly con-tributed to increase the probability of calves dying,such that a year with average overall harassment had2.26 times the mortality of a hypothetical year with noattacks. In years of high intensity and frequency ofattacks, many older calves died near the end of theseason, probably reflecting the cumulative effect ofgull harassment on calf health. However, calf mortal-ity was not affected by prey density, and extremelyhigh mortality was not related to extremely high fre-quency or intensity of attacks, indicating that deathsare also influenced by other unidentified factors.These findings imply that chronic micropredationcontributed to the unprecedented high calf mortalityobserved in PV and that other marine mammal popu-lations ex periencing seabird attacks could bethreatened. Información suministrada por el agente en SIGEVAPalabras Clave
kelp gullsright whalesmicropredationcalf deathsstress