128 



only naturally occurring sea otter population in the Western Hemi- 

 sphere south of Alaska. Only 33 years after its exciting rediscovery, 

 the rare southern sea otter, opening its polluted shellfish with pop 

 bottle, rock, or beer can for tool, is faced with new threats to its 

 survival. In the southern portion of their range, otters are occasion- 

 ally shot and, with increasing small craft traffic, more are being fatally 

 injured in boating accidents. 



The City of Monterey, Calif., expects to quadruple its accommoda- 

 tions for boats, thanks to $300,000 in Federal assistance, thus greatly 

 increasing the threat of boating deaths. From my analysis of the data 

 concerning 111 recovered carcasses, fatal boatmg accident injuries 

 appear to be the greatest single cause of death. 



Female sea otters continue to bear pups within sight of oil tankers 

 whose frequency of passage and potential for spills increase yearly. 

 Completion of the controversial Alaskan pipeline will compound this 

 threat. 



One of the sea otters killed by the three commercial aibalone divers, 

 who were sentenced last year, contained in its fat 33 p.p.m. total DDT 

 residues. Although they were nearly exterminated for their furs, not 

 their meat, analytical data from many otters reveal that their tissues 

 greatly exceed the 7 p.p.m. considered unfit for human consumption. 



The fate of the California and Florida brown pelicans is well 

 known. Large numbers of aborted California sea lions were dis- 

 covered in May 1970.^ Karl Kenyon of the Fish and Wildlife Service 

 reported 1,200 p.p.m. DDT in one sea lion pup on San Miguel Island.^ 

 Recent studies have indicated that DDT can cause reproductive dam- 

 age in newborn mammals.^ 



Recent public health awareness of chlorinated hydracarbons, such 

 as DDT, and heavy metals, such as cadmium and mercury, appear- 

 ing in many species of marine life has resulted in great economic losses 

 to some affected commercial fisheries. 



For example, the jack mackerel fishery in southern California was 

 condemned in 1969 because of high DDT levels and 89 percent of the 

 swordfis'h were condemned this year because of high mercury levels, 

 as well as approximately 2 percent of the tuna. 



At the present time, Dr. John Martin and George Knauer at Hop- 

 kins Marine Station, Pacific Grove, Calif., are determining heavy 

 metal levels in plankton, surface and midwater fishes, cephalopods and 

 marine mammals inhabiting the central and southern California cur- 

 rent regions. 



Sea otter livers and kidneys from recovered carcasses have been 

 tested for their cadmium, chromium, copper, lead, and zinc con- 

 tent. All these metals can be toxic to mammals, and three of them, 

 cadmium, lead and chromium^ — especially chromium with a valence 

 of six — are well known cumulative poisons. 



Of the three elements, cadmium is by far the most potentially dan- 

 gerous, as it is responsible for several known harmful conditions in 

 mammals. These include decalcification of human bones, degenera- 



^Odell, D. 1970. Premature pupping in the California sea Hon, Proc. Seventh Ann. 

 Conf. Biol. Sonar and Div. Mamm., Menlo Park, Calif., Stanford Research Institute, 

 pp. 185-190. 



' Kenyon, K. W. 1970. Personal communication to James A. Mattlson, Jr., M.D., 506 

 East Romie Lane, Salinas, Calif. 93901. 



» Heinrich, W. L., et al. 1971. DDT administered to neonatal rats induces persistent 

 estrus syndrom. Science, vol. 173. Aug. 



