A century-long decline of the fishery for the Eastern oyster Crassostrea virginica (Gmelin, 1791) in Maryland and Virginia stimulated numerous efforts by federal, state, and nongovernmental agencies to restore oyster populations, with limited success. To learn from recent efforts, we analyzed records of restoration and monitoring activities undertaken between 1990 and 2007 by 12 such agencies. Of the 1,037 oyster bars (reefs, beds, or grounds) for which we obtained data, 43% experienced both restoration and monitoring, with the remaining experiencing either restoration or monitoring only. Restoration activities involved adding substrate (shell), transplanting hatchery or wild seed (juvenile oysters), bar cleaning, and bagless dredging. Of these, substrate addition and transplanting seed were common actions, with bar cleaning and bagless dredging relatively uncommon. Limited monitoring efforts, a lack of replicated postrestoration sampling, and the effects of harvest on some restored bars hinders evaluations of the effectiveness of restoration activities. Future restoration activities should have clearly articulated objectives and be coordinated among agencies and across bars, which should also be off limits to fishing. To evaluate restoration efforts, experimental designs should include replication, quantitative sampling, and robust sample sizes, supplemented by pre-and postrestoration monitoring.
The degree and temporal context of variations in ribosome content during nutrient starvation of two copiotrophic marine bacteria, Vibrio alginolyticus and Vibrio furnissii, have been examined. The organisms were starved either by nutritional shift-down or by consumption of limiting nutrients resulting from growth into stationary phase. Measurements of the amount of hybridization to 16S rRNA-specific probes revealed that the cells retained between 10 and 26% of their original rRNA content after 15 days of starvation. In V. alginolyticus, losses in stationary-phase cells occurred rapidly (1 to 2 days), whereas cells shifted into starvation remained larger and retained considerably more rRNA. The ability of V. alginolyticus to recover from starvation was assessed after cells were maintained for 2, 8, and 15 days in nutrient-depleted medium. The pattern of recovery at the level of rRNA accumulation depended upon the duration of nutrient deprivation and the manner in which it was imposed. Stationary-phase cells starved for 2 days had only slight relative increases in rRNA levels after excess nutrients were added. As the duration of starvation lengthened to 8 and 15 days, increasingly greater amounts of rRNA (30 and 70 times preenrichment values, respectively) were transcribed after nutrient enrichment. Shift-down cells recovered from 2 and 8 days of starvation without extensive rRNA production. After 15 days, nutrient enrichment caused 16S rRNA levels to increase 30-fold. The results indicate that the mechanisms controlling starvation-survival in these marine bacterial species are linked to the physiological state at the onset of starvation and that the subsequent pattern of recovery will depend upon how starvation was initiated.
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