Search USGS⌕ Search

Geology topics

A.C. Matz

Publications and source records attributed to A.C. Matz.

3 recordsLinked to original sources
USGS2016

An exploratory assessment of thiamine status in western Alaska Chinook salmon (Oncorhynchus tshawytscha)

This study was conducted to investigate the thiamine status of Chinook salmon Oncorhynchus tshawytscha . Egg thiamine levels in Yukon and Kuskokwim River Chinook were examined in 2001 and 2012. Muscle and liver thiamine in Chinook, coho O. kisutch , chum O. keta , and pink O. gorbuscha salmon were measured in northern Bering Sea juveniles and the percentage of the diet containing thiaminase, an enzyme that destroys thiamine, was calculated. Only 23% of the eggs were thiamine replete (> 8.0 nmol·g -1 ) in 2012. Seventy-four percent of the eggs had thiamine concentrations (1.5–8.0 nmol·g -1 ) which can lead to mortality from secondary eff ects of thiamine defi ciency. Only 3% of the eggs had < 1.5 nmol·g -1 associated with overt fry mortality. In 2001 egg thiamine in upper Yukon Chinook was 11.7 nmol·g -1 which was higher than that measured in 2012 (6.2 nmol·g -1 ) and paralleled Chinook productivity. Total thiamine (nmol·g -1 ) in Bering Sea Chinook muscle (3.8) was similar to coho (4.15), but lower than in chum (8.9) and pink salmon (9.6). Thiaminase-containing prey in Chinook (63%) and coho (36%) stomachs were elevated compared to those of chum (3%) and pink (5%) salmon. These results provide evidence of egg thiamine being less than fully replete. Thiamine deficiency was not observed in juvenile muscle tissue, but differences were present among species reflecting the percentage of diet containing thiaminase. Additional studies are recommended.

Alaska↗
USGS2009

Red-throated loons (Gavia stellata) breeding in Alaska, USA, are exposed to PCBs while on their Asian wintering grounds

Red-throated loons (Gavia stellata) breeding in Alaska declined 53% during 1977-1993. We compare concentrations of environmental contaminants in red-throated loons among four nesting areas in Alaska and discuss potential ramifications of exposure on reproductive success and population trends. Eggs from the four areas had similar total polychlorinated biphenyl (PCB) concentrations, but eggs from the Arctic coastal plain had different congener profiles and greater toxic equivalents (TEQs) than eggs from elsewhere. Satellite telemetry data indicate that red-throated loons from the Arctic coastal plain in northern Alaska winter in southeast Asia, while those breeding elsewhere in Alaska winter in North America. Different wintering areas may lead to differential PCB accumulation among red-throated loon populations. For eggs from the Arctic coastal plain, TEQs were great enough to postulate PCB-associated reproductive effects in piscivores. The correlation between migration patterns and PCB profiles suggests that red-throated loons breeding in northern Alaska are exposed to PCBs while on their Asian wintering grounds.

Environmental Pollution↗