Effective Population Size in Winter-Run Chinook Salmon

Winter-run chinook salmon from the Sacramento River, California, is federally listed as endangered. Since 1989 there has been aprogram to augment the natural population by capturing adults, artificially spawning them, raising tine young and releasing the smolt. Here we estimate the effective population size of these captive-raised fish, the natural run, and the combination of both groups over the three-year period from 1991 to 1993. We find that the most appropriate estimate of the effective population size of the captive-raised progeny is a variance estimate of effective population size standardized so that the number of released smolts returning to spawn was the same as the number of spawners used to produce the smolts originally. We have generated 10,000 random samples to simulate returns from these released progeny. The estimates of the effective population sizes in 1991, 1992, and 1993 were only 7.02, 19.07, and 7.74, respectively. We then determined limits on the effective population size of the natural run based on 0.1 and 0.333 of the run-size estimates. Using estimates of the captive proportion of the run, the minimum estimates of the effective population size of the overall run for the three years were 21.9, 127.3, and 39.0, and the maximum estimates were 61.6, 401.0, and 108.7. It does not appear that the hatchery program has reduced the overall effective population size. The run sizes in each year are extremely low, however, and it is possible that fish will be lost from this run in one of the years in the immediate future, making reestablishment of a healthy run even more difficult.     

Chemical composition of the NH3-HNO3-H2SO4-NaCl system in the atmosphere of Athens,Greece

This paper presents a procedure for estimating the distribution of ionic material in the NH₃-HNO₃-H₂SO₄-NaCl system and applies this procedure in a particular case. The data used were measurements of HNO₃, NH₃, NO ₃ ^– , SO ₄ ^– , NH ₄ ⁺ Cl^– and Na⁺ performed during February 1989 – February 1990 in a central Athens street with high traffic density. According to the procedure, ions combine in the following manner: Na⁺ combines preferentially with SO ₄ ^– , then with NO ₃ ^– , followed by NH ₄ ⁺ with the remaining SO ₄ ^– and then with the remaining NO ₃ ^– to form bisulphates, sulphates and nitrates. The combination procedure showed that the main constituents of the NH₃-HNO₃-H₂SO₄-NaCl system are primarily (NH₄)₂SO₄ and, to a lesser extent, NH₄NO₃ and NH₄HSO₄, with mean and maximum concentrations, during morning hours, (NH₄)₂SO₄: 14.5 (max 46.8), NH₄NO₃: 2.97 (max 23) and NH₄HSO₄: 1.78 (max 40.6) µg m^–3. Lower concentations of Na₂SO₄, NaHSO₄, NaNO₃ and NH₄Cl and very low concentrations of H₂SO₄ are also present, depending on the availability of NaCl. It became apparent from the ionic distribution that there is sufficient NH₃ to neutralize the H₂SO₄ and HNO₃. It was also shown that a significant fraction of the HNO₃, especially on days with high pollution, occurs as aqueous NO ₃ ^– . A number of empirical equations have been proposed, which enable the approximate estimation of the constituents of the NH₃-HNO₃-H₂SO₄-NaCl system from air pollution monitoring data and meteorological parameters.     

Traditional management and conservation of shea trees (<Emphasis Type="Italic">Vitellaria paradoxa</Emphasis> subspecies <Emphasis Type="Italic">nilotica</Emphasis>) in Uganda

Traditional practices are universally recognised as a basis for conservation of biodiversity. However, such practices are often not included in natural resource conservation policies. This study assessed local conservation practices of shea trees (Vitellaria paradoxa) within different farming systems in Uganda and developed conservation guidelines for the species. The assessment involved 300 respondents, 15 focus groups and 41 key informants. Content analysis was used to identify the most important management and conservation practices. Local uses were categorised on the basis of shea tree products while differences in conservation practices were analysed using the Friedman test. The results show that eight shea tree products are used for 36 different purposes. Respondents’ age significantly influenced their knowledge about the shea tree. Traditional conservation practices include on-farm retention during cultivation and the use of folklore (mainly taboos), customs and rituals. Traditional management practices include weeding, bush burning, pollarding and pruning. Based on the current management and traditional conservation practices, a framework for the conservation of shea trees is proposed for integration into conservation policy decisions.     

UV-ozonation of eleven major pesticides as a waste disposal pretreatment

The time required to destroy 3 concentrations (10, 100, and 1000 ppm) of 9 formulated herbicides (alachlor, atrazine, bentazon, butylate, cyanazine, 2, 4-D, metolachlor, metribuzin, and trifluralin) and two formulated insecticides (carbofuran and malathion) by ultraviolet (UV)-ozonation (O₃) was measured in a 66 UV lamp unit. The time required for 90% destruction was dependent on the concentration and increased as the concentration of pesticide increased. UV irradiation in the presence of ozone rapidly photooxidized all pesticides at 10 and 100 ppm and averaged 22 and 61 min, respectively. Longer times were required for pesticides at 1000 ppm.     

Measured summertime concentrations of particulate components,Hg0, and speciated polycyclic aromatic hydrocarbons at rural sites in New York State

Daily PM2.5 samples, Hg0 and speciated polycyclic aromatic hydrocarbon (PAH) were simultaneously collected at Potsdam and Stockton site in NY during the summers of 2000 and 2001. Samples for determination of the mass concentration and chemical composition of the PM2.5 were obtained with a speciation network PM2.5 sampler. Chemical composition including trace elemental composition, water-soluble ions, and elemental carbon were analyzed. Elemental mercury and PAHs were sampled separately. Daily PM2.5 concentrations ranged from 0.47 to 53.7 microg m(-3) at the Potsdam site, and from 0.82 to 47.23 microg m(-3) at the Stockton site with large daily differences between the two sites. Potsdam consistently had lower mass values than Stockton. The greatest contributors to the PM2.5 mass (generally >0.1 microg/m(3)) were sulfate, nitrate, ammonium, and BC at both sites. Seventeen PAHs were identified at each site in 2000 and the average total concentrations were 3.2 ng/m(3) and 2.9 ng/m(3) at the Potsdam and Stockton sites, respectively. The mean vapor phase mercury concentration at the Potsdam site (2.4 +/-1.2 ng m(-3), n=93) was higher than that at the Stockton site (1.2 +/- 1.0 ng m(-3), n=60) in 2000, whereas in 2001, the average concentrations were 1.1 ng m(-3) and 1.6 ng m(-3) at the Potsdam and Stockton sites, respectively. In general, vapor phase mercury concentrations increased with increasing ambient temperature at the Stockton site in 2000. These differences in values between 2000 and 2001 can be largely explained by distinct differences in the meteorological regimes that dominated in the different years.