Alec G. Maule

Cortisol mediated suppression of salmonid lymphocyte responses invitro

The suppressive activity of cortisol on the in vitro induction of coho salmon (Oncorhynchus kisutch) B cell activation was examined. Suppression was observed with splenic and pronephric (anterior kidney) derived lymphocytes. The kinetics of cortisol-induced suppression revealed distinct differences in the sensitivity of splenic and pronephric lymphocytes. Pronephric lymphocytes were only sensitive to cortisol early in the induction of the antibody response, whereas the splenic cells were sensitive to cortisol throughout the culture period. Addition of supernatants from antigen stimulated pronephric cultures completely restored the ability of pronephric lymphocytes to produce an antibody response, suggesting that this glucocorticoid-suppression may be mediated by inhibition of lymphokine production.

Physiological Effects of Collecting and Transporting Emigrating Juvenile Chinook Salmon past Dams on the Columbia River

Abstract Emigrating juvenile salmonids are collected at McNary Dam on the Columbia River and transported past the three downstream dams to avoid mortalities caused by passage through power-generating turbines. During the 1982–1984 seaward migrations of juvenile fall and spring chinook salmon Oncorhynchus tshawytscha, we used an array of physiological measurements (plasma cortisol and glucose, white blood cell counts) and challenge tests (saltwater challenge, secondary stress, and swimming endurance) to identify the stressful elements in these activities. Sequential increases in plasma cortisol titers offish sampled at the physically separable points in the collection system led us to conclude that the elements of the system stressed fish cumulatively. Furthermore, there were decreases in numbers of white blood cells, in osmoregulatory ability, and in swimming endurance during the first 24 h after fish were collected. Increasing the water flow rate in the system after the 1982 season seemed to reduce total...

Glucocorticoid receptors in leukocytes and gill of juvenile coho salmon (Oncorhynchus kisutch)

We demonstrated that cytosol from the gill of coho salmon (Oncorhynchus kisutch) had saturable, high affinity, low capacity binding to radiolabeled [3H]cortisol (Kd = 2.24 +/- 0.28 nM, mean +/- 1 SE; Nmax = 41.4 +/- 7.4 fmol/mg protein) and radiolabeled [3H]triamcinolone acetonide (TA; Kd = 0.38 +/- 0.03 nM, Nmax = 37.8 +/- 4.9 fmol/mg protein). Similarly, TA bound to cytosolic fractions of leukocytes harvested from spleen (Kd = 0.32 +/- 0.03 nM, Nmax = 8.3 +/- 2.0 fmol/mg protein) and anterior kidney (Kd = 0.37 +/- 0.03 nM, Nmax = 30.2 +/- 5.2 fmol/mg protein) and to whole leukocytes from spleen (Kd = 0.30 +/- 0.04 nM, Nmax = 445 +/- 57 sites/cell) and anterior kidney (Kd = 0.40 +/- 0.04 nM, Nmax = 1198 +/- 180 sites/cell). The competition hierarchies of steroid competitors were the same for both ligands and all tissues (TA greater than cortisol greater than 17 alpha-hydroxyprogesterone greater than cortisone greater than aldosterone greater than testosterone). The differences in ligand binding in leukocytes from spleen and anterior kidney are consistent with previously reported organ-dependent sensitivity of leukocytes to cortisol.

Evidence of Detrimental Effects of Environmental Contaminants on Growth and Reproductive Physiology of White Sturgeon in Impounded Areas of the Columbia River

This study sought to determine whether wild white sturgeon from the Columbia River (Oregon) were exhibiting signs of reproductive endocrine disruption. Fish were sampled in the free-flowing portion of the river (where the population is experiencing reproductive success) and from three reservoirs behind hydroelectric dams (where fish have reduced reproductive success). All of the 18 pesticides and almost all of the 28 polychlorinated biphenyls (PCBs) that were analyzed in livers and gonads were detected in at least some of the tissue samples. Metabolites of p,p′-dichlorodiphenyltrichloroethane (DDT) [p,p′-dichlorodiphenyldichloroethylene (DDE) and p,p′-1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD)] were consistently found at relatively high levels in fish. Some males and immature females showed elevated plasma vitellogenin; however, concentrations were not correlated with any of the pesticides or PCBs analyzed. Negative correlations were found between a number of physiologic parameters and tissue burdens of toxicants. Plasma triglycerides and condition factor were negatively correlated with total DDT (DDD + DDE + DDT), total pesticides (all pesticides detected – total DDT), and PCBs. In males, plasma androgens and gonad size were negatively correlated with total DDT, total pesticides, and PCBs. Fish residing in the reservoir behind the oldest dam had the highest contaminant loads and incidence of gonadal abnormalities, and the lowest triglycerides, condition factor, gonad size, and plasma androgens. These data suggest that endocrine-disrupting chemicals may be accumulating behind dams over time. Overall, results of this study indicate that exposure to environmental contaminants may be affecting both growth and reproductive physiology of sturgeon in some areas of the Columbia River.

Identifying stakeholder-relevant climate change impacts: A case study in the Yakima River Basin, Washington, USA

Designing climate-related research so that study results will be useful to natural resource managers is a unique challenge. While decision makers increasingly recognize the need to consider climate change in their resource management plans, and climate scientists recognize the importance of providing locally-relevant climate data and projections, there often remains a gap between management needs and the information that is available or is being collected. We used decision analysis concepts to bring decision-maker and stakeholder perspectives into the applied research planning process. In 2009 we initiated a series of studies on the impacts of climate change in the Yakima River Basin (YRB) with a four-day stakeholder workshop, bringing together managers, stakeholders, and scientists to develop an integrated conceptual model of climate change and climate change impacts in the YRB. The conceptual model development highlighted areas of uncertainty that limit the understanding of the potential impacts of climate change and decision alternatives by those who will be most directly affected by those changes, and pointed to areas where additional study and engagement of stakeholders would be beneficial. The workshop and resulting conceptual model highlighted the importance of numerous different outcomes to stakeholders in the basin, including social and economic outcomes that go beyond the physical and biological outcomes typically reported in climate impacts studies. Subsequent studies addressed several of those areas of uncertainty, including changes in water temperatures, habitat quality, and bioenergetics of salmonid populations.

Gas Bubble Disease Monitoring and Research of Juvenile Salmonids : Annual Report 1996.

This document describes the project activities 1996--1997 contract year. This report is composed of three chapters which contain data and analyses of the three main elements of the project: field research to determine the vertical distribution of migrating juvenile salmonids, monitoring of juvenile migrants at dams on the Snake and Columbia rivers, and laboratory experiments to describe the progression of gas bubble disease signs leading to mortality. The major findings described in this report are: A miniature pressure-sensitive radio transmitter was found to be accurate and precise and, after compensation for water temperature, can be used to determine the depth of tagged-fish to within 0.32 m of the true depth (Chapter 1). Preliminary data from very few fish suggest that depth protects migrating juvenile steelhead from total dissolved gas supersaturation (Chapter 1). As in 1995, few fish had any signs of gas bubble disease, but it appeared that prevalence and severity increased as fish migrated downstream and in response to changing gas supersaturation (Chapter 2). It appeared to gas bubble disease was not a threat to migrating juvenile salmonids when total dissolved gas supersaturation was < 120% (Chapter 2). Laboratory studies suggest that external examinations are appropriate for determining the severity of gas bubble disease in juvenile salmonids (Chapter 3). The authors developed a new method for examining gill arches for intravascular bubbles by clamping the ventral aorta to reduce bleeding when arches were removed (Chapter 3). Despite an outbreak of bacterial kidney disease in the experimental fish, the data indicate that gas bubble disease is a progressive trauma that can be monitored (Chapter 3).