Male Pseudohermaphroditism in the Bowhead Whale, Balaena mysticetus

Abstract

Examination of two bowhead whales, Balaena mysticetus, revealed an unusual assembly of reproductive structures. Although the external phenotype was female, the gonads were underdeveloped testes. In the more thoroughly studied of the two whales, all derivatives of the mesonephric (wolffian) and paramesonephric (mtillerian) ducts were absent, and there was an apparently normal male karyotype (40 autosomes + XY). These findings suggest a failure of androgen expression consistent with the syndrome of complete testicular feminization reported in other species. Structural comparisons with two normal male bowheads confirm abnormal development in the two affected whales.

Organochlorine pesticides and polychlorinated biphenyls in fin whales (Balaenoptera physalus) from the Gulf of California

“…Considering that maximum OCs values found in the present study (2700 ng g −1 lw) were higher than those found in baleen whales characterized with endocrine disorders (1400 ng g −1 lw) (Tarpley et al, 1995; Hoekstra et al, 2002), the potential for these chemicals to present a health effect in the individuals with the highest concentrations should not be dismissed. Because of the low calf production [females give birth to a single calf every 2 years] (Aguilar, 2001), the grade of isolation (Bérubé et al, 1998, 2002), and the small population size (600 animals) of the Gulf of California fin whales (Urbán‐Ramírez et al, 2005; Díaz‐Guzmán, 2006), even slight impairment of reproduction effectiveness in a small number of individuals could affect the status this population (Bérubé et al, 1998, 2002; Urbán‐Ramírez et al, 2005).…”

“…Studies describing hormonal disorders in marine mammals caused by OC exposure have focused principally on odontocetii, and pinnipeds because they accumulate high amounts of OC in their tissues (Fossi et al, 1999; Spinsanti et al, 2006; Hickie et al, 2007). Evidence of contaminant induced endocrine disruption in mysticetii species is relatively limited, however, these chemicals have been associated with transformation of epididymal and testicular tissue in North Pacific minke whales ( B. acutorostrata ) (Fujise et al, 1998; Fossi et al, 2003), pseudohermaphroditism in bowhead whales ( Balaena mysticetus ) from Alaska [440 ng g −1 lw ( n = 71) of ΣDDT] (Tarpley et al, 1995; Hoekstra et al, 2002) and fin whales from the Mediterranean Sea [mean ΣDDT = 5000 ng g −1 lw ( n = 27)] (Fossi et al, 2003).…”

“…The findings from our study support the generally held concept that concerns for the health effects of POPs are more relevant for odontocetes and pinnipeds than mysticetes. However, the effects of exposure to OC insecticides and PCBs on endocrine function and reproduction in baleen whales have been documented and indicate that OC compounds can interfere with the reproduction of mysticetes (Tarpley et al, 1995; Hoekstra et al, 2002; Fossi et al, 2003). DDTs and PCBs among others OCs have the potential for both estrogenic‐ antiandrogenic and antiestrogenic‐androgenic properties in fin whales (Marsili et al, 1998; Fossi et al, 2003).…”

Organochlorine Contaminant Levels in Eskimo Harvested Bowhead Whales of Arctic Alaska

“…have been implicated in affecting sexual or gonadal development, as early as in utero (Yamamoto et al, 1996). Although there is no cause-effect implied, true hemaphroditism has been documented in the St. Lawrence Estuary beluga whale (De Guise et al, 1994) and pseudohermaphroditism in the bowhead whale (Tarpley et al, 1995).…”

Disorders of Sexual Development in Wild and Captive Exotic Animals

“…obs.]. Post-mortem evaluation of 2 bowhead whales (Balaena mysticetus) presumed to be female based on external phenotype revealed the presence of underdeveloped testes but total absence of other reproductive structures derived from either Wolffian or Müllerian ducts [Tarpley et al, 1995]. Chromosome analysis in both individuals revealed a nor- mal male karyotype, 42,XY, and the individuals were considered male pseudohermaphrodites.…”