Fishes, biomass

When rainbow trout were transferred to fresh water (24+24 and 24+48 in Table III), both fenitrothion and its radioactive metabolites were eliminated from the fish. Thus after 48 hr in fresh water, 60% of the radioactivity originally contained in the fish had been excreted into the water and the degradation products accounted for one half of the total radioactivity in water. Fenitrothion in the fish biomass steadily decreased, although the rate was lower than in running water as will be described belcw. 

The Okhotsk Sea aquatory is divided into zones having specific ecological features (Suzuki, 1992). The spatial distribution of the fish biomass depends on seasonal conditions and to a great extent correlates with the layers outlined above. The use of sea biological resources is a function of this distribution. Fishing intensity essentially depends on knowledge of the biomass distribution in zones with specific environmental conditions. Many authors (Plotnikov, 1996 Aota et al., 1992) have tried to solve this task by means of models simulating ecosystem dynamics. However,... 

Thurow, F., 1997. Estimation of total fish biomass in the Baltic Sea during the 20th Century. ICES Journal of Marine Science, 54, 444-461. 

Monitoring programmes usually cover a network of sampling sites, each to be sampled from annually to once every six years. From each site, the species present, number and size of fish are recorded, providing information on population composition, abundance and age structure. Also, total weight of the catch and even individual weight of fish are sometimes recorded to give estimates of fish biomass. 

Table 3.5. Percentage (%) of dominant fish species in total fish biomass and some ecological indexes in the YS during 1985 2000 (Zheng et al., 2006)...

AMOUNT IN TOP 5 CM OF ALKE SEDIMENT AMOUNT IN FISH BIOMASS ... 

The chemical is introduced to the water compartment (Figure 11.2) at a fixed rate of 0.15 g hr for a 30-day period, followed by a 30-day clearance phase. The half-life for clearance from the fish biomass is estimated and the percent distribution of the chemical in all the compartments at the end of the 30-day clearance period is determined. 

Algae can be cultivated easily and quickly when compared to plants. They produce very high quantities of carotenoids compared to other sources (3.0 to 5.0% w/w on a dry weight basis). They contain both cis and trans isomers of carotenoids for high bioavailability and bioefflcacy, and also contain oxygenated carotenoids (xantho-phylls), which have greater bioactivity and better anticancer properties. The proteins from Dunaliella biomass can be utilized for bread and other products and whole cells can be utilized for animal, poultry, and fish foods because they are safe. ... 

Peech Cherewyk 2002 Tsui and Wang 2004). Phytoplankton have a constrained trophic position are not consumed by fish, wildlife, or humans, and are indirectly relevant to the pnbhc or the policy commnnity. They wonld respond veiy rapidly — within minntes or honrs — to changes in MeHg concentrations in water. Phytoplankton obtain MeHg directly from water (Mason et al. 1996), and algal density can inlinence concentrations of MeHg in phytoplankton via biomass dilntion (Pickhardt et al. 2002). 

Borgmann, U., 0. Kramar, and C. Loveridge. 1978. Rates of mortality, growth, and biomass production of Lymnaea palustris during chronic exposure to lead. Jour. Fish. Res. Board Canad. 35 1109-1115. 

Mirex may be removed from Lake Ontario by several mechanisms, including the transport of contaminated suspended particulate material via water outflow into the St. Lawrence River), biomass removal through fishing and migration (e.g. migrating eels contaminated with mirex), volatilization, and photolysis (Comba et al. 1993 Lum et al. 1987). Transport of mirex accumulated in body tissues by eels has been estimated to be 2,270 grams annually or twice the amount of mirex removed by transport of suspended particulates (1,370 grams annually) (Lum et al. 1987). 

To study the absorption of cis-chlordane by bluegill and Xenopus, the exposure was made to 5 ppb of insecticide. The biomass and volume was one 5-g fish/6L and three 27-g Xenopus/8L in 10-liter glass cylinders. The aeration of the water was kept to the minimum and the containers were covered with aluminum foil to reduce loss due to volatilization. The radioactivity in control water without animals and in water with fish was monitored by counting 5 ml of water in 15 ml of Instagel (Packard Instruments) (16). 

Figure 2. Absorption of cyclodienes by fish and Xenopus in a static system (A), goldfish treated with photo-cis-chlordane (B), goldfish with cis-chlordane (C), blue gills with photodieldrin (D), blue gills with photo-cis-chlordane (E), bluegills with cis-chlorane and (F), Xenopus with ds-chlordane. All exposures were made at 5 ppb. (see Table 1 for biomass and volume of water).

This project was designed to demonstrate that the static water model ecosystems can be scaled up in size to provide sufficient amounts of biomass, soil, and water to study metabolism kinetics of pesticides. Fourteen kg of soil, treated with [l C]-trifluralin at 10 ppm, was flooded with 84 liters water. Blue-gill fish, snails, daphnids, and algae were exposed to this system for 72 days. Samples of soil, water, and organisms were periodically analyzed for trifluralin and eight metabolites. 

Eutrophication The overgrowth of algae in marine and fresh waters caused by an overabundance of nutrients. Once the algae die and their remains settle below the sea surface, microbially mediated decomposition of their biomass leads to O2 depletion and, potentially to fish and benthic kills. 

Decomposition rates of some organic substrates are reduced. Substantial changes in the species composition of primary producers occur. The richness of phytoplankton species is reduced, while biomass and productivity of phytoplankton are not reduced by acidification. The biomass of herbivorous and predaceous zooplankton is probably reduced because of reductions in numbers of organisms and/or reduction in their average size. Many benthic invertebrates such as species of snails, clams, crayfish, amphipods, and various aquatic insects are intolerant of low pH and are seldom found in acidic lakes. However, certain large aquatic insects such as water boatmen and gyrinids are very acid tolerant and may become the top predators in some acidified lakes. Acidification of aquatic systems has major effects on fish population. 

There is no single population parameter for brown trout suited to characterize the effects of minimum flow, and no data suggest the potential of a suitable minimum flow [100]. The effects of reduced flows vary with stream structure, hydro-physical variables, and fish species. As such, trout biomass and density can increase or decrease in minimum flow reaches. If the minimum flow discharge is not suitable to maintain fish habitats, a sharp decrease in trout density and a disruption in natural reproduction becomes apparent. Small-sized Ashes such as bullhead generally do not respond to a decrease in water depth caused by minimum flows, whereas adult brown trout are clearly affected by a reduction in pool habitat. 

Five weeJcs after sowing, the broccoli was transplanted into the field while wild mustard was planted directly on the date of broccoli transplant. The area was irrigated every wee)c with overhead sprin-)clers throughout the experiment and fertilized 10.1 L/ha fish emulsion ("Grow Force brand) at 30 and 57 days after set-up of the experiment. The plots were hand weeded selectively every 15 days, samples of the volunteer weeds were ta)cen through the plot method (18), and the number of different species, number of individuals of each species, and biomass (dry weight) were recorded for each plot. The dominance, frequency, density, and importance value were calculated for each species in each plot. 

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