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Juvenile dispersal and the exchange of offspring among fish populations in river–tributary networks are difficult to characterize, but they may play a substantial role in the dynamics of fisheries in these systems. We used geochemical signatures in otoliths to identify the natal origins of young-of-year smallmouth bass Micropterus dolomieu in the James River and a tributary, the Maury River, in Virginia. The trace element signatures (Sr:Ca, Rb:Ca, Mg:Ca, and Ba:Ca) in otoliths differed significantly between these two rivers, resulting in approximately 87% accuracy in classifying known-origin fry to their natal rivers. The variation in otolith composition reflected the variation in water chemistry within the system. We subsequently used classification functions and stock mixture analyses based on these signatures to identify the natal origins of age-1 juveniles collected from the same rivers 1 year later. The results indicate that approximately 50% of the age-1 smallmouth bass collected in the Jam...

After nearly 20 years of limited natural recovery of intertidal habitats along the Gulf Coast of the Kingdom of Saudi Arabia, large-scale remediation projects were conducted on approximately 1800 ha of tidal flat and salt marsh habitat. In Fall, 2011, multiple passes of mechanical tilling were used to break up oiled cohesive sediment layer across a heavily degraded sand tidal flat, to reduce subsurface liquid oil, and accelerate natural recovery. Rates and degrees of test deformities in three foram genera were measured from samples collected at degraded and healthy sand tidal flat sites. Dominant genera and rates of test deformity at a heavily oiled sand tidal flat (average surface and subsurface total petroleum hydrocarbon (TPH) = 10,000 ppm ) were: Peneroplis (41.0%), Ammonia (38.7%), Elphidium (54.7%). Rates of deformity in the same three genera collected at a healthy sand tidal flat habitat were: Peneroplis (11.8%), Ammonia (7.5%), Elphidium (13.9%). Nearly two years after the remediation event, results indicate a decreasing trend in percent foram deformities at the remediation site, which suggests oil toxicity as an ecological stressor has decreased as a result of remediation activities.