Unexpectedly low calf numbers within the spinner dolphin population off Hawaiʻi Island were revealed in a study led by scientists with the Marine Mammal Research Program (MMRP) at the University of Hawaiʻi at Mānoa, along with national and international collaborators. Their research, published in Endangered Species Research, determined that calves make up only about 9% of the population, a stark contrast to the 17% expected in a healthy, stable population, raising urgent concerns about the long-term survival of this isolated population.