Post by Admin on Jan 2, 2016 18:26:43 GMT
Contaminant exposure in outmigrant juvenile salmon from Pacific Northwest estuaries of the United States
Lyndal L. Johnson · Gina M. Ylitalo · Mary R. Arkoosh · Anna N. Kagley · Coral Stafford · Jennie L. Bolton · Jon Buzitis · Bernadita F. Anulacion · Tracy K. Collier
Abstract To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured in tissues and prey of juvenile Chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest. PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of Chinook and coho salmon sampled from all estuaries, as well as in Chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently. Of the two species sampled, Chinook salmon had the highest whole body contaminant concentrations, typically 2–5 times higher than coho salmon from the same sites. In comparison to estuarine Chinook salmon, body burdens of PCBs and DDTs in hatchery Chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were highest in Chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries’ estimated threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile Chinook salmon from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in Chinook salmon from the Duwamish Estuary and Grays Harbor .Juvenile Chinook salmon are likely absorbing some contaminants during estuarine residence through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents ,at concentrations significantly correlated with contaminant body burdens in fish from the same sites.
Keywords Chinook salmon. Coho salmon .Contaminants. PAHs. PCBs. DDTs. Pesticides .Washington. Oregon. Estuary
Introduction
Estuaries are important habitats for salmon during the juvenile stage of their life cycle, when they make the transition from freshwater to the ocean (Healey, 1982). Estuaries provide outmigrating juvenile salmon with a refuge from predators, a rich food supply that supports rapid growth, and appropriate conditions for the physiological adaptation to saltwater (Dorcey et al., 1978; Simenstad et al., 1982). However, urban and industrial development may impair the quality of estuar-ine habitats. Estuaries located near urban centers often receive inputs of toxic contaminants from municipal and industrial activities (Brown et al., 1998; USEPA, 1997), which may be taken up by juvenile salmon and their prey. Because juvenile salmon are in a period of rapid development, and undergoing many physiological changes during their residence in estuarine environments, they may be especially vulnerable to the deleterious effects of toxic chemicals.
The well-documented presence of chemically contaminated sediments in Puget Sound urban estuaries (e.g., Malins et al., 1982) prompted a series of studies to examine the degree to which juvenile salmon were exposed to toxic chemicals during estuarine residence (McCain et al., 1990; Varanasi et al., 1993; Stein et al., 1995; Stehr et al., 2000). Juvenile salmon (primarily Chinook and coho, Onchorhynchus tshawytscha and O. kisutch) were sampled from several urban and non-urban estuaries in Puget Sound including the Green River/Duwamish Estuary system in Seattle, the Puyallup River/Hylebos Waterway system in Tacoma, and the more rural Snohomish River and Nisqually River Estuaries. Juvenile Chinook salmon from hatcheries associated with sampled estuaries were also collected and whole bodies and stomach contents were analyzed for chemical concentrations. Results of these surveys showed that outmigrating juvenile Chinook salmon from the Duwamish and Hylebos Waterways exhibited consistent evidence of exposure to contaminants. Juvenile Chinook salmon from the Snohomish Estuary, which has some urban development, also appeared to be exposed to contaminants, but to a much lesser degree than salmon from the Duwamish and Hylebos Waterways. In addition, when held in tanks with flow-through seawater for a period of several months, juvenile salmon from the Duwamish Estuary exhibited reduced growth and reduced disease resistance when compared to salmon from either the Green River Hatchery (the primary source of salmon for the Duwamish Estuary) or to salmon from the nonurban Nisqually system (Arkoosh et al., 1998; Casillas et al., 1995). Similar effects were observed for juvenile salmon from the Hylebos Waterway (Arkoosh et al., 2001; Casillas et al., 1998). Chemical contaminant exposure in the estuary appeared to place additional stresses on juvenile Chinook salmon that could affect their long-term health and survival as they enter the marine environment.
To increase our knowledge of concentrations of chemical contaminants in outmigrant salmon in the Pacific Northwest, we carried out an expanded study from 1996–2001 in which juvenile coho and Chinook salmon were collected for contaminant analyses from a number estuaries in Washington and Oregon. Classified by the overall level of development and channel alteration in each estuary (Cortright et al., 1987), the sampling areas included: five deep draft estuaries, with the maximum level channel alteration and urban development (Duwamish Estuary, Columbia River, Grays Harbor, Yaquina Bay, and Coos Bay); two shallow draft estuaries with less extensive channel alteration and some urban and industrial development (Tillamook Bay and Coquille River), four conservation estuaries, where channel alteration is minimal and development is limited (Skokomish Estuary, Nisqually Estuary, Willapa Bay and Alsea Bay); and two natural estuaries, which are largely undeveloped for residential, commercial or industrial uses (Elk River and Salmon River). Predominantly wild fish were collected in the estuaries, although some fish of hatchery origin may have been sampled due to incomplete marking of hatchery fish. Juvenile Chinook salmon were also sampled from regional hatcheries to evaluate contaminant uptake during rearing but prior to release. Our results indicate that exposure to chemical contaminants is widespread in outmigrant juvenile Chinook and coho salmon, and concentrations in tissues of Chinook salmon from several estuaries are high enough to pose a potential threat to their health and survival.
Lyndal L. Johnson · Gina M. Ylitalo · Mary R. Arkoosh · Anna N. Kagley · Coral Stafford · Jennie L. Bolton · Jon Buzitis · Bernadita F. Anulacion · Tracy K. Collier
Abstract To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured in tissues and prey of juvenile Chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest. PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of Chinook and coho salmon sampled from all estuaries, as well as in Chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently. Of the two species sampled, Chinook salmon had the highest whole body contaminant concentrations, typically 2–5 times higher than coho salmon from the same sites. In comparison to estuarine Chinook salmon, body burdens of PCBs and DDTs in hatchery Chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were highest in Chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries’ estimated threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile Chinook salmon from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in Chinook salmon from the Duwamish Estuary and Grays Harbor .Juvenile Chinook salmon are likely absorbing some contaminants during estuarine residence through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents ,at concentrations significantly correlated with contaminant body burdens in fish from the same sites.
Keywords Chinook salmon. Coho salmon .Contaminants. PAHs. PCBs. DDTs. Pesticides .Washington. Oregon. Estuary
Introduction
Estuaries are important habitats for salmon during the juvenile stage of their life cycle, when they make the transition from freshwater to the ocean (Healey, 1982). Estuaries provide outmigrating juvenile salmon with a refuge from predators, a rich food supply that supports rapid growth, and appropriate conditions for the physiological adaptation to saltwater (Dorcey et al., 1978; Simenstad et al., 1982). However, urban and industrial development may impair the quality of estuar-ine habitats. Estuaries located near urban centers often receive inputs of toxic contaminants from municipal and industrial activities (Brown et al., 1998; USEPA, 1997), which may be taken up by juvenile salmon and their prey. Because juvenile salmon are in a period of rapid development, and undergoing many physiological changes during their residence in estuarine environments, they may be especially vulnerable to the deleterious effects of toxic chemicals.
The well-documented presence of chemically contaminated sediments in Puget Sound urban estuaries (e.g., Malins et al., 1982) prompted a series of studies to examine the degree to which juvenile salmon were exposed to toxic chemicals during estuarine residence (McCain et al., 1990; Varanasi et al., 1993; Stein et al., 1995; Stehr et al., 2000). Juvenile salmon (primarily Chinook and coho, Onchorhynchus tshawytscha and O. kisutch) were sampled from several urban and non-urban estuaries in Puget Sound including the Green River/Duwamish Estuary system in Seattle, the Puyallup River/Hylebos Waterway system in Tacoma, and the more rural Snohomish River and Nisqually River Estuaries. Juvenile Chinook salmon from hatcheries associated with sampled estuaries were also collected and whole bodies and stomach contents were analyzed for chemical concentrations. Results of these surveys showed that outmigrating juvenile Chinook salmon from the Duwamish and Hylebos Waterways exhibited consistent evidence of exposure to contaminants. Juvenile Chinook salmon from the Snohomish Estuary, which has some urban development, also appeared to be exposed to contaminants, but to a much lesser degree than salmon from the Duwamish and Hylebos Waterways. In addition, when held in tanks with flow-through seawater for a period of several months, juvenile salmon from the Duwamish Estuary exhibited reduced growth and reduced disease resistance when compared to salmon from either the Green River Hatchery (the primary source of salmon for the Duwamish Estuary) or to salmon from the nonurban Nisqually system (Arkoosh et al., 1998; Casillas et al., 1995). Similar effects were observed for juvenile salmon from the Hylebos Waterway (Arkoosh et al., 2001; Casillas et al., 1998). Chemical contaminant exposure in the estuary appeared to place additional stresses on juvenile Chinook salmon that could affect their long-term health and survival as they enter the marine environment.
To increase our knowledge of concentrations of chemical contaminants in outmigrant salmon in the Pacific Northwest, we carried out an expanded study from 1996–2001 in which juvenile coho and Chinook salmon were collected for contaminant analyses from a number estuaries in Washington and Oregon. Classified by the overall level of development and channel alteration in each estuary (Cortright et al., 1987), the sampling areas included: five deep draft estuaries, with the maximum level channel alteration and urban development (Duwamish Estuary, Columbia River, Grays Harbor, Yaquina Bay, and Coos Bay); two shallow draft estuaries with less extensive channel alteration and some urban and industrial development (Tillamook Bay and Coquille River), four conservation estuaries, where channel alteration is minimal and development is limited (Skokomish Estuary, Nisqually Estuary, Willapa Bay and Alsea Bay); and two natural estuaries, which are largely undeveloped for residential, commercial or industrial uses (Elk River and Salmon River). Predominantly wild fish were collected in the estuaries, although some fish of hatchery origin may have been sampled due to incomplete marking of hatchery fish. Juvenile Chinook salmon were also sampled from regional hatcheries to evaluate contaminant uptake during rearing but prior to release. Our results indicate that exposure to chemical contaminants is widespread in outmigrant juvenile Chinook and coho salmon, and concentrations in tissues of Chinook salmon from several estuaries are high enough to pose a potential threat to their health and survival.