Approximately 100,000 black scoters use the Restigouche River in New Brunswick Canada every spring as a staging area before movement north to breeding areas in Quebec and Manitoba. The coastline of the Restigouche River has paper mills and power plants that possibly are having adverse impact on the seaduck habitat. There is a need to examine the possibility of contaminants in the food resources available for seaducks feeding in these areas on migration. There also is a need to create some baseline data on what food resources are available for these ducks and to monitor the availability of these food resources. If the food sources decline due to human impacts, then the seaduck population that use these areas as a migration stopover will decline.
The proposed new study would create a baseline database of the food sources available to seaducks in the Restigouche River. This data will then be correlated with feeding ecology of the ducks feeding in these areas. The specific objectives are as follows:
1. Determine what benthic food organisms are available for migrating seaducks in the Restigouche River.
2. Determine food habits of seaducks feeding in the Restigouche River.
3. Analyze bivalves and scoters for possible contaminants (e.g., organometalics, organochlorines, tri-butylin).
Food Availability: Benthic samples will be collected in late April early May 2003 to determine availability of food available to scoters. Boat surveys will be conducted on the Restigouche River to locate general areas where seaducks are foraging. If the ducks are randomly distributed throughout the area then a systematic grid design will be used for sampling the food items in the River. Approximately 100 grabs with a Petersen dredge will be taken from a boat at grid stations. Food items from benthic samples will be analyzed separately and then all samples will be averaged to calculate average percent volume of the whole River. Food Habits: Because no ducks are available from local hunters during the spring, 25 males and 25 females will be collected with a shotgun from a boat to determine food ussed by these ducks. During dissection the ducks will be aged, weighed, sexed, and selected organs will be measured. The location of the ducks when collected will be recorded for the food availability component of study. The quantities of food in gullet (esophagus and proventriculous) and gizzard will be analyzed. The weight of the gizzard will be recorded before and after removal of food items. Food material will be separated, identified to species, and then measured volumetrically. The average percent volume and frequency of occurrence will be tabulated for each food item.Contaminants: Duck tissues from the ducks collected for food habits will be analyzed for contaminants. Samples of duck foods collected in the benthic sampling will also be analyzed for contaminants. Analyses of samples for comparable results will be conducted at the same laboratory either at Moncton or the CWS lab at NWRC.
The output of this study will be a management report of the food used by seaducks in the Restigouche River that managers of this resource can use as an aide in managing the black scoter populations during migration. The report will also discuss the possibility of contaminants in the food resources available for seaducks feeding in these areas on migration. The baseline data on the quantity and quality of food resources available for these ducks will be important information to managers. If the food sources decline due to human impacts, then the seaduck population that use these areas as a migration stopover will also decline.