A stochastic model of temporal variations in monthly temperature, precipitation, snowfall, and resulting snowpack

We report a Monte Carlo representation of the long-term inter-annual variability of monthly snowfall on a detailed (1 km) grid of points throughout the southwest. An extension of the local climate model of the southwestern United States (Stamm and Craig 1992) provides spatially based estimates of mean and variance of monthly temperature and precipitation. The mean is the expected value from a canonical regression using independent variables that represent controls on climate in this area, including orography. Variance is computed as the standard error of the prediction and provides site-specific measures of (1) natural sources of variation and (2) errors due to limitations of the data and poor distribution of climate stations. Simulation of monthly temperature and precipitation over a sequence of years is achieved by drawing from a bivariate normal distribution. The conditional expectation of precipitation. given temperature in each month, is the basis of a numerical integration of the normal probability distribution of log precipitation below a threshold temperature (3°C) to determine snowfall as a percent of total precipitation. Snowfall predictions are tested at stations for which long-term records are available. At Donner Memorial State Park (elevation 1811 meters) a 34-year simulation - matching the length of instrumental record - is within 15 percent of observed for mean annual snowfall. We also compute resulting snowpack using a variation of the model of Martinec et al. (1983). This allows additional tests by examining spatial patterns of predicted snowfall and snowpack and their hydrologic implications.

Use of skeletochronological analysis to estimate the age of leatherback sea turtles Dermochelys coriacea in the western North Atlantic

Although growth rate and age data are essential for leatherback management, estimates of these demographic parameters remain speculative due to the cryptic life history of this endangered species. Skeletochronological analysis of scleral ossicles obtained from 8 captive, known-age and 33 wild leatherbacks originating from the western North Atlantic was conducted to characterize the ossicles and the growth marks within them. Ages were accurately estimated for the known-age turtles, and their growth mark attributes were used to calibrate growth mark counts for the ossicles from wild specimens. Due to growth mark compaction and resorption, the number of marks visible at ossicle section tips was consistently and significantly greater than the number visible along the lateral edges, demonstrating that growth mark counts should be performed at the tips so that age is not underestimated. A correction factor protocol that incorporated the trajectory of early growth increments was used to estimate the number of missing marks in those ossicles exhibiting resorption, which was then added to the number of observed marks to obtain an age estimate for each turtle. A generalized smoothing spline model, von Bertalanffy growth curve, and size-at-age function were used to obtain estimates of age at maturity for leatherbacks in the western North Atlantic. Results of these analyses suggest that median age at maturation for leatherbacks in this part of the world may range from 24.5 to 29 yr. These age estimates are much greater than those proposed in previous studies and have significant implications for population management and recovery.

Shortspine thornyhead (Sebastolobus alascanus) abundance and habitat associations in the Gulf of Alaska

Shortspine thornyhead (Sebastolobus alascanus) abundance was estimated from 107 video transects at 27 stations recorded from a research submersible in 1991 off southeast Alaska at depths ranging from 165 to 355 m. Numbers of invertebrates in seven major taxa were estimated, as was substrate type. Thornyhead abundance ranged from 0 to 7.5/100 m2, with a mean of 1.22/100 m2, and was positively correlated with depth and amount of hard substrate. Invertebrate abundances were not significantly correlated with numbers of thornyheads. Shortspine thornyhead abundance estimates from this study were several times higher than estimates produced by bottom trawl surveys off southeast Alaska in 1990 and 1993, the two years of survey that encompassed the submersible transects; however, the trend of increasing abundance with depth was similar in the trawl surveys and in the submersible transects, suggesting that trawl surveys systematically underestimate abundance of shortspine thornyheads

Eastern tropical Pacific corals monitor low latitude climate of the past 400 years

EXTRACT (SEE PDF FOR FULL ABSTRACT): We have measured coral growth band thickness and skeletal stable isotopic composition through a 371-year transect (AD 1583-1954) from a massive specimen of Pavona clavus from the Galápagos Islands. ... We observe a general cooling trend during 1860-1954, corresponding to the end of the Little Ice Age, an interval characterized by general warming at many mid-latitude sites. Variance at sunspot cycle frequencies in growth rate, stable isotopic, and trace element composition implies a direct or indirect link between the solar cycle and climate modulation in the eastern Pacific.

Fire, climate, and vegetation: the sedimentary record of fire in montane meadows, Sierra Nevada, California, USA [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Though knowledge of fire occurrence and weather pattern relationships has been used for many years by land managers in, for instance, prescribed fire planning, understanding of the relationship between Holocene climates and fire is just beginning to be investigated. We are investigating this relationship in a major mountain range in California, examining charcoal and pollen content in sediments of montane meadows to compare paleo-fire and paleo-vegetation (thus, climate) sequences for the Holocene.

Marine fisheries development in India, 2000 AD: a perspective

The status of marine fisheries research and development in India is discussed and the need for a high power national body to coordinate these activities is stressed. Priority areas for research and development have been outlined. It has been stressed that the strategy should be to achieve a production target of 3 million tonnes on the capture fisheries front (2.5 million tonnes from the inner shelf and 0.5 million tonnes from the outer shelf and slope areas) and 1 million tonne through aquaculture by 2000 AD.

Effects of artificial feeds on production of fishes in polyculture

A study on the effects of artificial feeds on the growth and production of fishes in polyculture in 6 ponds along with some limnological conditions was conducted. Species of Indian and Chinese major carps (Labeo rohita, Catla catla, Cirrhinus mrigala, Hypophthalmicthys molitrix) and catfishes (Clarias batrachus, Clarias gariepinus) were stocked in 6 ponds. Stocking rate in both cases were 32044 fingerlings per hectare. Ratio of species of Rui:Catla:Mrigal:Silver carp:African Magur:Local Magur=25%:25%:5%:25%:14%:6%. Fertilization and artificial feeds were given in 3 ponds (treatment I) and only fertilization was done in other 3 ponds (treatment II). Average yield/ha/yr was 7.903 m.ton in case of fertilization and artificial feeding application and 3.374 m.ton in case of only fertilization application. Urea, TSP and cow dung were applied fortnightly at the rates of 400 kg/ha/yr, 2000 kg/ha/yr and 4000 kg/ha/yr respectively. Wheat bran, rice bran and mustard oil cake were given daily as an artificial feed in treatment I. Whereas treatment II was conducted without any artificial feed. Ratio of artificial feed was wheat bran:rice bran:oil cake=2:2:1 (by wt). Absence of artificial feed in 3 ponds under treatment II seriously affected the growth and production of fish.

Pathogenicity of Aeromonas sobria to Thai silver barb (Barbodes gonionotus Bleeker) and its sensitivity to some antibiotic agents

Five isolates of Aeromonas sobria, collected from the diseased fish were selected for detection the pathogenicity following water-born infection method on silver barbs (Barbodes gonionotus) at the selected exposure dose 2.5x10⁸ CFU/ml which was standardized by preliminary test. In the experimental condition lesion and mortality were found in fishes. Among the isolate, Ass17 Ass19, Ass31 and Ass36 were successfully infected 20-60% fishes. Another isolate Ass20 was found non-pathogenic. Drug sensitivity test was performed by six antibiotics viz. Oxytetracycline, Oxolinic acid, Chloramphenicol, Stilphamethozazole, Streptomycin, Erythromycin. All the isolates showed variable reaction patterns to antibiotics. Most of the isolates were found sensitive to Oxytetracycline (OT), Oxolinic acid (OA) and Chloramphenicol (C) but resistance to Erythromycin and Sulphamethoxazole (SXT). Isolate Ass31 found resistant to Oxolinic acid.

Storage characteristics of solar-dried Indian mackerel

Fresh Rastrelliger kanagurta (Indian mackerel) was thoroughly washed, eviscerated, cleaned and salted overnight with dry salt (fish : salt :: 5:1). Salted mackerel was dried in solar drier and on cement floor under direct sun for three days. The temperature inside the drier was 948°C higher than the ambient temperature. The rate of drying was higher in solar drier than on cement floor. The dried fish packed in 300-gauge polythene bags was subjected to biochemical, microbiological and organoleptic evaluation at regular intervals to assess the storage life. The overall quality of fish dried in solar drier was better than that of the fish dried on cement floor under direct sun.