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M. Wolgamood

Publications and source records attributed to M. Wolgamood.

4 recordsLinked to original sources
USGS2005

Can diet-dependent factors help explain fish-to-fish variation in thiamine-dependent early mortality syndrome?

To provide insight into the reasons why offspring of certain salmonine females exhibit early mortality syndrome (EMS) in the Great Lakes whereas others do not, we measured the egg concentrations of potential biochemical markers (stable isotopes of nitrogen and carbon, fatty acid signatures, and lipid-soluble carotenoids and vitamins) that are indicative of differing food web and trophic structure. To corroborate the presence of EMS, we also measured the egg content of thiamine vitamers. For all the stocks of coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha we studied, there was a very high correspondence between EMS and low concentrations of unphosphorylated thiamine in unfertilized eggs. For salmonine stocks in the Platte River, Thompson Creek, and the Swan River, Michigan, small but significant shifts occurred in measures of egg carotenoids, retinoids, ??15N depletion, and fatty acid profiles of fish producing normal offspring relative to those exhibiting EMS. Egg thiamine concentrations in Chinook salmon from the Little Manistee River, Michigan, in the low-EMS group were only marginally above the threshold for EMS induction. Along with this small thiamine differential, there was no evidence of differing food web or dietary factors between EMS-positive and normal Chinook salmon from the Little Manistee River. Further investigations are required to determine the potential dietary sources for the observed differences in biochemical markers between EMS-positive and normal fish. These findings are generally consistent with the hypothesis that a more diverse forage base may help to limit overall dietary content of species that contain thiaminase, such as alewives Alosa pseudoharengus, and may lead to improved embryonic survival for feral salmonids. ?? Copyright by the American Fisheries Society 2005.

Journal of Aquatic Animal Health↗
USGS2005

Temporal and spatial variation of early mortality syndrome in salmonids from Lakes Michigan and Huron

To assess the extent that early mortality syndrome (EMS) impacts different Pacific salmonid stocks and the association of EMS with thiamine, we collected eggs of coho salmon Oncorhynchus kisutch from three Lake Michigan tributaries (Platte River, Thompson Creek, and Root River) in 1996-2001. We also obtained eggs of Chinook salmon O. tshawytscha from Lake Michigan (Little Manistee River) and Lake Huron (Swan River) in 1998-2001. Unfertilized eggs from individual females were frozen for thiamine analysis, and the remainder were fertilized and reared until first feeding. We observed a high incidence of EMS in offspring when total egg thiamine levels were less than 1.7 nmol/g in both coho and Chinook salmon. In Lake Michigan strain coho salmon from the Platte River, EMS occurred in more than 70% of monitored families in 1996, 1999, 2000, and 2001, while 1997 and 1998 were years when EMS was low (<25%). Hinchenbrooke strain coho salmon from Thompson Creek exhibited greater impacts from EMS in the years when EMS was low in the Lake Michigan strain coho salmon from the Platte River. Similar to coho salmon, Lake Michigan Chinook salmon also exhibited EMS (>70%) in 1999, 2000, and 2001. Chinook salmon from Lake Huron exhibited high (>70%) EMS in 2001, moderate (40-60%) EMS in 1999, and low (<25%) EMS in 1998. Our data suggest that the incidence of EMS in salmonids varies by species, location, and year. The data support the general contention that EMS in salmonids is associated with low egg thiamine content. ?? Copyright by the American Fisheries Society 2005.

Journal of Aquatic Animal Health↗
USGS2005

Thiamine status in adult salmonines in the Great Lakes

In 1996 and again in 1999, hatchery personnel noted that some Lake Michigan coho salmon Oncorhynchus kisutch from fall spawning runs on the Platte River weir exhibited abnormal wiggling behavior that was similar to the behavior exhibited by thiamine-deficient Atlantic salmon Salmo salar , from the Baltic Sea. Samples of eggs or gonads, muscle, and liver from salmon and lake trout Salvelinus namaycush exhibiting abnormal behaviors were collected to determine the extent to which the behaviors were related to a thiamine deficiency. We compared these values with those found in normally behaving fish that produced offspring with high embryonic survival. In all adult fish exhibiting abnormal behavior, tissue residues of thiamine were among the lowest observed in the Great Lakes. Where embryonic survival was assessed, abnormal adult behavior was also associated with very high levels of offspring mortality due to early mortality syndrome. While the overall ecological significance remains to be determined, it appears that adult fish also exhibit neurological dysfunction and mortality associated with thiamine deficiency.

Journal of Aquatic Animal Health↗