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  • Author or Editor: Stephanie K. Venn-Watson x
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Abstract

Objective—To evaluate health indicators for a population of bottlenose dolphins in the US Navy Marine Mammal Program (MMP) by use of data acquired from 1988 through 2007.

Design—Retrospective cohort study.

Animals—167 bottlenose dolphins.

Procedures—The following indicators were used to evaluate the health of dolphins during the 20-year period: 5-year age structure, median survival age, annual survival rates, mortality rates, and neonatal and calf survival and mortality rates. Limitations of these population measurements as health indicators for dolphins were assessed.

Results—Crude mortality rates of dolphins for 1988 through 1992, 1993 through 1997, 1998 through 2002, and 2003 through 2007 were 3.1%, 4.7%, 3.6%, and 2.4%, respectively; during these same 4 study periods, median survival ages were 14.3, 14.4, 17.7, and 26.1 years, respectively, and mean survival rates were 0.98, 0.97, 0.97, and 0.99, respectively. From 1988 through 1997, 1998 through 2002, and 2003 through 2007, neonatal mortality rates were 4 of 16, 5 of 20, and 2 of 14 neonates, respectively. During these 3 study periods, mean annual survival rates for calves < 3 years old (excluding neonates that died at < 30 days old) were 0.97, 0.92, and 0.99, respectively.

Conclusions and Clinical Relevance—Although there were limitations to the measurement of some health indicators, use of multiple methods indicated that the health of dolphins in the MMP population was comparable to, if not better than, that published for other dolphin populations. The MMP population of dolphins may provide useful reference values of health indicators for use in assessment of other managed dolphin populations.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Case Description—3 adult (24- to 43-year-old) Atlantic bottlenose dolphins (Tursiops truncatus) with chronic episodic malaise and inappetence associated with high serum aminotransferase (alanine aminotransferase and aspartate aminotransferase) activities, high serum iron concentration, and serum transferrin saturation > 80% were evaluated.

Clinical Findings—Results of histologic examination of liver biopsy specimens revealed hemosiderosis in all 3 dolphins. Except for chronic lymphocytosis in 1 dolphin, results of extensive diagnostic testing revealed no other abnormalities. For each dolphin, a diagnosis of iron overload of unknown origin was made.

Treatment and Outcome—Phlebotomy treatment was implemented to reduce body stores of iron. Each phlebotomy procedure removed 7% to 17% (1 to 3 L) of estimated blood volume. Treatment consisted of an induction phase of weekly phlebotomy procedures for 22 to 30 weeks, which was complete when serum iron concentration and aminotransferase activities were within reference ranges and serum transferrin saturation was ≤ 20% or Hct was ≤ 30%. Total amount of iron removed from each dolphin was 53 to 111 mg/kg (24.1 to 50.5 mg/lb) of body weight. One dolphin required maintenance procedures at 8- to 12-week intervals when high serum iron concentration was detected.

Clinical Relevance—Although the cause of the iron overload and high serum aminotransferase activities remained unknown, phlebotomy treatment successfully resolved the clinicopathologic abnormalities, supporting a role of iron overload in the hepatopathy of the 3 dolphins.

Full access
in Journal of the American Veterinary Medical Association

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.

Full access
in Journal of the American Veterinary Medical Association