Distribution Of Juvenile River Herring In The Potomac River
J. E. Warriner, J. P. Miller, and J. Davis
This report concerns the distribution of juvenile alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) in the tidal portion of the Potomac River as determined in 1968. The river courses for 100 nautical miles from the Lower Falls at Washington, D. C. to empty into the Chesapeake Bay some 60 miles from the Virginia capes. It is second only to the Susquehanna River in freshwater input to the bay, contributing 18% of the total. The salinity at the mouth is approximately 18 ppt., and salt water intrudes 70 to 75 miles. The upper tidal portion is heavily polluted by domestic wastes from the Washington Metropolitan area. Although much of the sewage is treated, over enrichment causes massive algal blooms.
Preliminary Results from Striped Bass Tagging in Virginia, 1968-1969
George G. Grant, Victor G. Burrell Jr., C. E. Richards, and Edwin B. Joseph
A total of 8525 striped bass, Morone saxatilis (Walbaum), were tagged and released in Virginia during 1968 and 1969. Releases were grouped in three periods: (1) 3195 in winter 1968, (2) 2439 during summer-fall 1968; and (3) 2891 in winter 1969. Streamer disc tags, employed in winter 1968, were subsequently replaced by internal anchor tags (Floy Tag No. FD-67). This substitution shortened application time and eliminated a source of bias introduced by the entanglement of disc tags in gill nets. Releases were made in the James, York, and Rappahannock rivers in all three periods. Rewards of one dollar have been paid for return of tags. Percentages of returns within tagged year-classes increased with age, indicating change in fishing mortality rates of striped bass during their initial 3 to 4-year residence in the lower Chesapeake Bay system.
Comparative strength of the 1966 year class of striped bass, Roccus saxatilis (Walbaum), in three Virginia rivers
George G. Grant and Edwin B. Joseph
The age composition, as determined from scale impressions, of striped bass stocks in the James, York, and Rappahannock Rivers during the period June 1967 - March 1968 indicates a relative deficiency of the 1966 year class in the James River. Similar results are shown in samples from non-selective gear (pound nets, fyke nets), selective gear (gill nets, haul seines, hook-and-line), and routine surveys using a 30-foot semi-balloon trawl.
Nutrient assimilation in a Virginia tidal system
Morris L. Brehmer
Over-enrichment leading to environmental degradation and the production of aquatic nuisance conditions have destroyed the multi-use potential of several coastal tidal systems in the United States. The Middle and South Atlantic and the Gulf Coast drainage basins are especially vulnerable to this type of destruction because of their hydraulic characteristics. Many are drowned pre-Pleistocene river valleys having a large basin capacity relative to the fresh-water inflow. This results in a horizontal-boundary type estuary characterized by higher salinities on the left side (looking downstream) and the absence of a sharp salinity gradient from surface to bottom of the water column . The surface waters have a net downstream movement and the bottom waters have a net upstream movement with a theoretical level of no net motion near mid -depth. The time of passage or net non -tidal movement in t he fresh -water tidal section is almost directly related to the inflow rate at the most downstream physical barrier and to the basin capacity.
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