Evaluation of annual survival and mortality rates and longevity of bottlenose dolphins (Tursiops truncatus) at the United States Navy Marine Mammal Program from 2004 through 2013

Abstract

Objective-To evaluate annual survival and mortality rates and the longevity of a managed population of bottlenose dolphins (Tursiops truncatus). Design-Retrospective cohort study. Animals-103 bottlenose dolphins at the US Navy Marine Mammal Program (MMP). Procedures-Population age structures, annual survival and crude mortality rates, and median age at death for dolphins > 30 days old were determined from 2004 through 2013. Results-During 2004 through 2013, the annual survival rates for MMP dolphins ranged from 0.98 to 1.0, and the annual crude mortality rates ranged from 0% to 5%, with a mean of 2.7%. The median age at death was 30.1 years from 2004 through 2008 and increased to 32 years from 2009 through 2013. The maximum age for a dolphin in the study was 52 years. Conclusions and Clinical Relevance-Results indicated that the annual mortality rates were low and survival rates were high for dolphins in the MMP from 2004 through 2013 and that the median age at death for MMP dolphins during that time was over 10 years greater than that reported in free-ranging dolphins. These findings were likely attributable to the continually improving care and husbandry of managed dolphin populations.

Monitoring bottlenose dolphin leukocyte cytokine mRNA responsiveness by qPCR

“…Veterinary care of dolphins in managed populations has continued to progress with the adoption of advanced medical technologies available in humans and other animal species [ 1 ]. Concerns about the effects of anthropogenic pollutants have driven a considerable body of research into the immunotoxicology of marine mammals [ 2 ].…”

Increased Dietary Intake of Saturated Fatty Acid Heptadecanoic Acid (C17:0) Associated with Decreasing Ferritin and Alleviated Metabolic Syndrome in Dolphins

“…In these studies, MMP dolphins have been older, had no differences in body mass index, and had consistently lower levels of stress hormones compared to Sarasota Bay dolphins [ 12 ]. MMP dolphins have higher annual survival rates, lower mortality rates, and longer lives compared to wild dolphins, including those living in Sarasota Bay [ 12 , 14 , 15 ]. As such, in addition to advanced age, dietary differences have been proposed as a possible risk factor for metabolic syndrome in dolphins [ 14 ].…”

A 25-y longitudinal dolphin cohort supports that long-lived individuals in same environment exhibit variation in aging rates

“…While our findings demonstrate associations between accelerated aging rates and morbidity, including higher risks of developing anemia and lymphopenia compared with dolphins with slower aging rates, we did not include an analysis of mortality in our study, for two primary reasons. First, the annual mortality rate of dolphins at the Navy Marine Mammal Program is low (2.7%), and many dolphins in this study were still alive when we initiated it (40). Second, in general, evaluating associations between aging rate and mortality in natural, long-lived populations that are relatively small has significant limitations due to mortalities not associated with agingrelated processes (e.g., acute infections with primary pathogens).…”

“…Navy dolphins live in the same oceanic environment, are fed the same well-controlled and monitored fish diet, and do not typically receive chronic medications during their 30-to 50-y lifespan. This good care has resulted in Navy dolphins living longer than wild dolphins; whereas the average lifespan of wild dolphins is 20 y, Navy dolphins live an average of 32.5 y (39,40). More than 30% of the current Navy dolphin population is between 30 and 55 y old, with an oldest recorded age of 57 y. Interestingly, not all aging dolphins at the Navy develop overt chronic aging-associated conditions despite sharing the same environment, health care, and diet (20,41).…”