SEDIMENT DISPERSION IN SALMON SPAWNING STREAMS: THE INFLUENCE OF FLOODS AND SALMON REDD CONSTRUCTION1

ABSTRACT: Magnetically tagged particles were used to investigate the effects of sockeye salmon (Oncorhynchus nerka) and floods on the dispersion of coarse bed material in the Stuart‐Takla region, British Columbia, Canada. The dominant annual sediment transporting event in the channels is the snowmelt flood events, with lesser activity usually accomplished during summer floods. Annually in August, the channel bed material is reworked by the Early Stuart sockeye salmon spawning, as the fish excavate the streambed to deposit and bury their eggs. These nesting cavities are called redds. Results from 67 tracer recovery experiments over five years were highly variable, subject to the magnitude of floods and the returning population of salmon. Overall, the depositional pattern from nival flood events usually demonstrated a high degree of clast mobilization, long travel distances (up to 150 m), and mean depths of burial up to 18 cm. Summer flood events showed somewhat lower rates of mobilization, distances of travel, and depths of burial. Although the fish did not move the tracers very far, their effect on the bed was generally quite pervasive ‐ up to 100 percent of the clasts were mobilized, and the depth of burial was considerable (mean burial depths up to 14 cm). The amount of vertical mixing of sediment by salmon was often on the same order of magnitude as flood events. The significant vertical mixing of sediments by the fish has important implications for the mobility of sediment in the stream. Since any armoring layer formed during high flows throughout the year is subject to the bioturbation of salmon, this suggests that the transport threshold in the creeks remains relatively low. Salmon likely play an integral role in the sediment transport dynamics and annual sediment budget of the lower reaches of these creeks.     

Familial marker chromosome due to 3:1 Disjunction of t(9;15) in a grandparent

An extra small chromosome detected in amniotic fluid was identified as the product of a translocation [46,XX,t(9;15)(p24;q11.2)]. This case is unusual in that individuals with the unbalanced karyotype resulting from a 3:1 disjunction are phenotypically normal.     

Fetal renal vein thrombosis,hydrops fetalis,and maternal lupus anticoagulant. A case report

Hydrops fetalis with fetal renal vein thrombosis in a mother with antiphospholipid antibody syndrome detected post-partum suggests an underlying pathogenetic association that may provide new strategies for treatment of a lethal disorder.     

Persistence of individually distinctive display patterns in fatigued side-blotched lizards ( Uta stansburiana)

Iguanian lizards perform conspicuous species-typical push-up displays, which are used in territory advertisement, threat, and courtship contexts. Subtle individually distinctive differences in push-up characteristics have been suggested to play a role in the recognition of social partners. However, if the structure of push-ups is responsive to changing physiological states then their capacity to promote recognition may be limited. The current study evaluated whether the push-ups performed while in an experimentally imposed state of fatigue by male side-blotched lizards (Uta stansburiana), retain the individually distinctive characteristics apparent in rested lizards. We found repeatable among-individual differences in the duration and the relative height of push-up components. Repeatability values did not change consistently between the rested and fatigued conditions, nor when both conditions were pooled, indicating that these push-up characteristics do not change with fatigue. Similarly, discriminant functions that were generated using push-ups from one state assigned push-ups performed in an alternate state to the correct individuals. Furthermore, when analyzed independently of individual identity, the values of display parameters examined in the current study did not change significantly between states, and discriminant function analysis could not reliably classify push-ups to the correct state. Taken together the results show that individually distinctive push-up characteristics are robust to effects of fatigue, consistent with their suggested role in social recognition. In the future, video playback experiments can test whether lizards utilize the signature-like characteristics of push-ups to discriminate among individuals.Communicated by T. Czeschlik     

Natural resources policy 1975–1985

Natural resources policy in the United States is a matter for deep concern. It is inconsistent, often outdated, and grossly overdependent on direct regulation vis-à-vis adjustments in the defective system of economic incentives. This policy also fails to recognize the tight web of interdependences among all resource problems, including those of environmental resources. This paper explores these interdependencies and develops a coherent program of natural resources policies. The chief elements are reduced reliance on direct regulation, increased reliance on economic incentives, measures to cancel unfavorable distributive effects, measures to improve the competitiveness and performance of the natural resource industries, and reorganization of both legislative and administrative branches of government.     

Metals, Boron, and Selenium in Neosho Madtom Habitats in the Neosho River in Kansas, U.S.A.

In 1991 and 1992 we determined the levels of metals, arsenic, boron, and selenium in the Neosho River drainage in southeastern Kansas, the primary habitat for the threatened Neosho madtom (Noturus placidus). We evaluated concentrations in sediments, mussels (Quadrula pustulosa and Q. metanevra), and fish(Percina phoxocephala, Cyprinus carpio,and Ictiobus bubalus) from three sites on theNeosho River and one site on the Cottonwood River. We also evaluated contaminant concentrations in C. carpio composite samples collected by theKansas Department of Health and Environment (KDHE)at two additional locations on the Neosho River in1990–92. Sediments were contaminated by lead. Concentrations of selenium, boron, and most metalsin mussels were low to normal for biota. Arseniclevels in mussels and fish suggest low-levelcontamination of biota. Aluminum, barium, manganeseand strontium concentrations were much higher inmussels than in fish. Five fish composite sampleshad cadmium concentrations that indicate chronicdeleterious effects on biota. Lead concentrationsin six fish samples were elevated. Mercuryconcentrations in most large fish compositesexceeded concentration for protection of animalsthat might consume them. We believe that reductionsin cadmium, lead, and mercury contamination, inparticular, would benefit aquatic life in theriver.