Environmental Engineering Reference
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tern suggests that the closely related and endangered least tern is not being affected
by DDT. The IAP to the Organochlorine TMDL for Newport Bay and Watershed
has recommended (IAP
2009
) the least tern as a sensitive indicator for the potential
toxicity of DDT to wildlife in Newport Bay.
3.1.6
DDT in Marine Mammals
In April 2006, and again in December 2013, a comprehensive review of the scien-
tifi c literature was undertaken to assess what is currently known regarding the
effects of DDT in marine mammals, either resident to, or capable of visiting,
Newport Bay, California. The fi rst step of the review was to determine the species
that should be included. Although there are numerous marine mammal species
found in the northwestern Pacifi c Ocean, relatively few species reside in, or visit,
Newport Bay.
Those that may potentially reside in the area for signifi cant periods include the
California sea lion (
Zalophus californianus
) and harbor seal (
Phoca vitulina
). Those
species that may enter Newport Bay for at least short periods—an unlikely but con-
servative approach—include the Pacifi c bottlenose dolphin (
Tursiops gilli
), rough-
toothed dolphin (
Steno bredanensis
) and common dolphin (
Delphinus delphis
), and
two fi lter-feeding baleen whale species—the minke whale (
Balaenoptera acuto-
rostrata
) and the migratory gray whale (
Eschrichtius gibbosus
; Ingles
1965
; Burt
and Grossenheider
1976
).
Therefore, electronic database searches were conducted via both the ISI Web of
Science and BIOSIS Previews using the following topical keywords:
Seals and DDT
Sea Lions and DDT
Dolphins and DDT
Whales and DDT
Several hundred documents dating from the mid-1960s through 2013 were iden-
tifi ed. However, most involved species not relevant to the Newport Bay region
(i.e., not listed above). Notwithstanding, a signifi cant number of reports were iden-
tifi ed and are summarized below. Although no search can necessarily identify and
locate all publications on a topic, those summarized below provide a reasonable
summary of what is currently known regarding DDT in marine mammals that may
either reside in or visit Newport Bay.
One important factor to consider in this review is the virtual lack of publications
encountered that describe the toxic actions or endpoints of DDT in the subject
marine mammals. There are two key reasons for this. First, logistically marine
mammals are very diffi cult to directly utilize in the statistically-signifi cant numbers
needed for valid potency or other mechanistic investigations. Although sea otters
may only weigh a few pounds, whales are excessively large and not practical to
handle or house. Second, marine mammals have been protected by the United States
Government for many years, which has signifi cantly reduced access for any purpose,
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