Dramatic increase in sterility of male Sitka Blacktail deer in Alaska believed to be due to environmental contamination

[Emily]

Hunters noticed sterility in male Sitka Blacktail deer in the mid-1990's:

http://nrahuntersrights.org/Article.aspx?id=1797

An Outstanding Sitka Blacktail ?Cactus Buck?
By James P. ?Jake? Jacobson Published: 4/8/2009
[snip]
I harvested my first buck in 1957 and my first non-typical buck in 1994. All objects of my hunting pursuits have been unique and special to me, but that non-typical was near the top of the list. It was a bilaterally cryptorchid buck, meaning its testes had not descended from the gut into the scrotum?a cactus buck, as they are often called, with antlers still in velvet in November. In 1995 I harvested three more non-typicals, all cryptorchids, all sterile. Since then, the percentage of these non-typicals in the areas I hunt has increased exponentially. Since 2003, 74 percent of the bucks taken in one ?hot zone? have been sterile cryptorchids....

The latest studies favor an environmental toxin being the cause of the sterility.
http://onlinelibrary.wiley.com/doi/10.1111/j.1469-1795.2008.00174.x/abstract

Animal Conservation

Volume 11, Issue 3, pages 234?246, June 2008

Competing hypotheses for the etiology of cryptorchidism in Sitka black-tailed deer: an evaluation of evolutionary alternatives
E. K. Latch1,
R. P. Amann2,
J. P. Jacobson3,
O. E. Rhodes Jr.1

Article first published online: 15 APR 2008

DOI: 10.1111/j.1469-1795.2008.00174.x

? 2008 The Authors. Journal compilation ? 2008 The Zoological Society of London

Abstract

On the Aliulik Peninsula (AP) of Kodiak Island, Alaska, 70% of male Sitka black-tailed deer (SBTD; Odocoileus hemionus sitkensis) are bilaterally cryptorchid (both testes fail to descend; male is sterile). Both genetic and environmental factors have been proposed as possible causes of this problem. We investigated the possibility that population genetic processes (isolation, inbreeding and genetic drift) have contributed to an increased frequency of cryptorchidism in this population. Overall, SBTD on major islands throughout Alaska have unusually low levels of genetic diversity, though we identified a likely glacial refugium on Prince of Wales Island in the Alexander Archipelago. Within the Kodiak Archipelago, deer on the AP did not exhibit the patterns of genetic isolation, inbreeding and drift that would be expected if cryptorchidism in this population was the result of a founder mutation(s). Instead, our data favor exposure to environmental contaminants as a likely alternative mechanism causing high prevalence of cryptorchidism on the AP.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1874179/

Environ Health Perspect. 2006 April; 114(S-1): 51?59.
Published online 2005 October 21. doi: 10.1289/ehp.8052

PMCID: PMC1874179
Copyright This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI

Monograph
Testis and Antler Dysgenesis in Sitka Black-Tailed Deer on Kodiak Island, Alaska: Sequela of Environmental Endocrine Disruption?
D.N. Rao Veeramachaneni,1 Rupert P. Amann,1 and James P. Jacobson2
1 Animal Reproduction and Biotechnology Laboratory, Colorado State University, Fort Collins, Colorado, USA
2 Arctic Rivers Guide Service, Kodiak, Alaska, USA
Address correspondence to D.N. Rao Veeramachaneni, Animal Reproduction and Biotechnology Laboratory, Campus Delivery 1683, Colorado State University, Fort Collins, CO 80523.
The authors declare they have no competing financial interests.
Received January 31, 2005; Accepted July 13, 2005.


Abstract
It had been observed that many male Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Kodiak Island, Alaska, had abnormal antlers, were cryptorchid, and presented no evidence of hypospadias. We sought to better understand the problem and investigated 171 male deer for phenotypic aberrations and 12 for detailed testicular histopathology. For the low-lying Aliulik Peninsula (AP), 61 of 94 deer were bilateral cryptorchids (BCOs); 70% of these had abnormal antlers. Elsewhere on the Kodiak Archipelago, only 5 of 65 deer were BCOs. All 11 abdominal testes examined had no spermatogenesis but contained abnormalities including carcinoma in situ?like cells, possible precursors of seminoma; Sertoli cell, Leydig cell, and stromal cell tumors; carcinoma and adenoma of rete testis; and microlithiasis or calcifications. Cysts also were evident within the excurrent ducts. Two of 10 scrotal testes contained similar abnormalities, although spermatogenesis was ongoing. We cannot rule out that these abnormalities are linked sequelae of a mutation(s) in a founder animal, followed by transmission over many years and causing high prevalence only on the AP. However, based on lesions observed, we hypothesize that it is more likely that this testis?antler dysgenesis resulted from continuing exposure of pregnant females to an estrogenic environmental agent(s), thereby transforming testicular cells, affecting development of primordial antler pedicles, and blocking transabdominal descent of fetal testes. A browse (e.g., kelp) favored by deer in this locale might carry the putative estrogenic agent(s).
Keywords: antler dysgenesis, CIS, cryptorchidism, Leydig cell tumor, microlithiasis, rete carcinoma, seminoma, Sertoli cell tumor