The Yukon River is the fourth largest river in North America, yet the ecology of its fishes has not been well described. During the spring and summer of 2002-04, we sampled the downstream migrations of fishes in the Yukon River mainstem near the Canada-U.S. border, using a rotary auger trap. Age-0 juvenile chinook salmon, Oncorhynchus tshawytscha, were the most common fish in the catch, and they peaked in abundance in mid-June. Smaller numbers of age-1 chinook salmon and age-0 chum salmon, O. keta, were caught earlier in the season. Over 80% of the remaining catch consisted of young-of-theyear Coregoninae (whitefish), presumably moving from natal areas to summer rearing habitats. Few adult whitefish were captured, probably because our sampling terminated before fall spawning migrations began. Both juveniles and adults were captured for six other winter or spring spawning species that we encountered. Our results indicate that the Yukon River mainstem is used extensively as a migration corridor. This reach of the mainstem has very high suspended sediment levels in summer; its significance as rearing habitat remains unknown. Further studies are required to delineate the extent of migrations and the population structure for the non-anadromous species.

Contractors convert design into reality. They are presumed as a major contributor of carbon emissions from the construction development. Carbon reduction strategies were proposed in previous studies. Nevertheless, contractors were often criticised for standing aloof to adopt them. Some argued that the contractors may not have contractual leverage to challenge the decisions made by the developers and the consultants. Nonetheless, there has been a lack of research that focuses on how different construction project organisations (CPOs) may be affecting carbon reduction strategies adoption. This paper presents a study that investigates the effect of the construction project organisations have on the contactors' adoption of carbon reduction strategies. An industry survey was conducted in Melbourne, Australia. 200 questionnaires were sent to the registered contractors. Monte Carlo simulations were conducted to examine how the priorities of strategies adoption may be affected by the CPOs. The results indicate that developers and the design consultants are influential to contractors' decision in adopting those carbon reduction strategies that may incur additional project cost. The results indicate that decisions towards the adoption of strategies may not be swayed towards their effectiveness of achieving carbon reduction. Instead, tightening planning and building regulations might affect decisions.