This pronounced trend of declining water supply had a 
number of negative impacts on physical properties and biological 
productivity of both the Sea of Azov and the San Francisco Bay 
estuarine systems: 
1. An increase in the frequency of salt intrusion into the 
upper part of the Delta and Bay (Cloern and Nichols, 
1985a; Nichols et. al. 1986) and, in the case of the 
Sea of Azov, into the Don and Kuban River estuarine 
systems (Bronfman, 1977; Remisova, 1984a, b). 
2. An increase of mean salinity in San Francisco Bay from 
approximately 20 ppt (under outflow conditions of 34.2 
kin 3 or 27.7 MAF; Rozengurt, 1983b) to 27 ppt (15-17 
km 3 or 12.2-13.8 MAF) and, for the same period for 
the Sea of Azov, from 9 ppt (43.0 km 3 ) to 16 ppt 
(21-25 km 3 ). These changes represent mean increases 
of 0.3 ppt and 0.4 ppt per hyrological year, respective¬ 
ly, for the two water bodies. 
3. Significant reduction in the size and biological 
productivity of the "entrapment" (null) zones have 
occurred in the Delta and San Francisco Bay during the 
summer months. Compression of these nursery zones, 
their upstream movement, and the resulting changes in 
their biochemical and biological properties have been 
implicated as factors responsible for low survival 
rates of eggs, larvae, and fry and for significant 
population decreases (California Department of Fish and 
Game, 1976; Herrgesell et. al. 1983; Cloern and 
Nichols, 1985b). 
4. Reduction of sediment load discharge to the Delta-Bay 
Coastal Zone ecosystem (60-75 percent of the 8xl0 6 
tonnes discharged per year for mean natural runoff 
conditions; Krone, 1979). This leads us to speculate 
that the absence of sediment may be partially responsi¬ 
ble for levee failures in the Delta as well as for in¬ 
creased beach erosion in the near coastal zone, since 
both depend on deposition of sediment (each receives at 
least 30 percent of the Delta and Bay's sediment load; 
Kockelman et. al. 1982). 
5. In the Sea of Azov, there has been a 60 percent 
reduction in primary and secondary productivity and 
over 95 percent reduction in catches of anadromous fish 
(Goldman and Maysky, 1972; Makarov, et. al. 1982; 
Remisova, 1984a, b: Figure 6A) resulting from 
diversions of more than 60 percent of historic spring 
(and more than 45 percent of annual) flows. Russian 
scientists have determined that the reduction of runoff 
of about 1 km 3 reduces the Sea of Azov anadromous 
47 
