David W. Weller

Nontargeted Biomonitoring of Halogenated Organic Compounds in Two Ecotypes of Bottlenose Dolphins (Tursiops truncatus) from the Southern California Bight

Targeted environmental monitoring reveals contamination by known chemicals, but may exclude potentially pervasive but unknown compounds. Marine mammals are sentinels of persistent and bioaccumulative contaminants due to their longevity and high trophic position. Using nontargeted analysis, we constructed a mass spectral library of 327 persistent and bioaccumulative compounds identified in blubber from two ecotypes of common bottlenose dolphins (Tursiops truncatus) sampled in the Southern California Bight. This library of halogenated organic compounds (HOCs) consisted of 180 anthropogenic contaminants, 41 natural products, 4 with mixed sources, 8 with unknown sources, and 94 with partial structural characterization and unknown sources. The abundance of compounds whose structures could not be fully elucidated highlights the prevalence of undiscovered HOCs accumulating in marine food webs. Eighty-six percent of the identified compounds are not currently monitored, including 133 known anthropogenic chemicals. Compounds related to dichlorodiphenyltrichloroethane (DDT) were the most abundant. Natural products were, in some cases, detected at abundances similar to anthropogenic compounds. The profile of naturally occurring HOCs differed between ecotypes, suggesting more abundant offshore sources of these compounds. This nontargeted analytical framework provided a comprehensive list of HOCs that may be characteristic of the region, and its application within monitoring surveys may suggest new chemicals for evaluation.

Spotted seal haul-out patterns in a coastal lagoon on Sakhalin Island, Russia

Spotted seals (Phoca largha) are pagophilic seals distributed mainly in the Okhotsk, Bering, and Chukchi Seas (Shaughnessy and Fay 1977), but use coastal haul-outs during ice-free months (Burns 1970). These hauling areas are common in bays, estuaries, and river mouths, where spotted seals congregate near seasonally available and abundant prey, primarily spawning fishes (e.g., Tikhomirov 1961; Gol’tsev 1971; Makhnyr and Perlov 1988). Although the presence of spotted seals at coastal haul-outs can be continuous throughout the open water season (Frost et al. 1993), individual seals tend to spend relatively little time in these areas between extended near-shore foraging trips (Lowry et al. 1998). While annual habitat use patterns of spotted seals at sea have been documented (Lowry et al. 2000), haul-out patterns of seals summering in coastal regions are not well described. Spotted seals occur along the coast of Sakhalin Island, Russia, in the western Okhotsk Sea, during ice-free periods (Tikhomirov 1961; Kosygin et al. 1986; Lagarev 1988). Previous summer counts of spotted seals have suggested that nearly 10,000 seals use hauling areas on Sakhalin Island, which are found predominantly on the island’s eastern coast (Kosygin et al. 1986). Results presented here provide information on habitat use, numbers, and haul-out patterns of spotted seals in a coastal lagoon located on northeastern Sakhalin Island.