Otir Livifi}^ Resources — Coastal & Marine Erosxstenis 



265 



vary from year to year, making trends less 

 apparent than those of other bay species 

 (Lipcius and Van Engel 1990: National Marine 

 Fisheries Service. Annapolis. Maryland, unpub- 

 lished data; Fig. 3b). Populations appear to fol- 

 low a 7-12 year cycle and may be in the 

 "trough" of this cycle at present. This percep- 

 tion and increasing annual harvests as fishery 

 efforts shift to crabs from other species have 

 prompted Maryland and Virginia to begin to 

 regulate the blue crab fishery. 



Striped Bass 



Probably the most monitored fish species in 

 the bay, striped bass populations have increased 



about 25% a year since 1984, after falling to 

 low levels in the early 1980"s (Gibson 1993; 

 Fig. 3c). Increases are at least partially attrib- 

 uted to a moratorium on harvest from 1985 to 

 1989 to allow improvement of the age and sex 

 structure of the spawning stock. The 1993 

 young-of-the-year index, a measure of numbers 

 of juvenile fish entering the population, is the 

 highest on record (National Marine Fisheries 

 Service, Annapolis, Maryland, unpublished 

 data) and may he related to the timing of high 

 freshwater flows, nutrient inputs, and increases 

 in planktonic prey (Blankenship 1994), which 

 may interact to allow large numbers of young 

 fish to survive after hatching. 



ooooooooooo 



Year 



Fig. 2. Forest cover in the 

 Chesapealce Bay waterslied. 16.^0- 

 1990. 



120 

 100 

 80 

 60 

 40 

 20 



Mii MD landings 



I VA landings 



a. Oyster 



ttiwiMMimiit 



MD reporting system change - 



c. Striped bass 



itilTioiliiJiiillB^^ 



d. American shad 



MD moratorium 



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Year 



Fig. 3a-d. Commercial landings in the Ctiesapeake Bay of (a) oysters, 1880-1992; (b) blue crab. 1880-1992 (population increases in the 1980's are partially due 

 to mandatory catch reporting requirements); (c) striped bass, 1887-1992; and (d) American shad, 1880-1992, 



