Beetles and lizards beware: Firing jets of water from its mouth, the archer fish can knock prey out of a branch five feet above the water.
Dry fly fishing is done with line and flies that float, joined by a leader, usually made of fine . The tapered leader is 3 to 5 meters long, thus nearly invisible where the fly is knotted, and the angler can replace the last meter of nylon as required. Unlike sinking fly (nymph) fishing, the "take" on dry flies is visible, explosive and exciting. While trout typically consume about 90% of their diet from below-water sources, the 10% of surface-level consumption by trout is more than enough to keep most anglers busy. Additionally, beginning fly anglers generally prefer dry fly fishing because of the relative ease of detecting a strike and the instant gratification of seeing a trout strike their fly. Nymph fishing may be more productive, but dry fly anglers soon become addicted to the surface strike.
The biological load, or bioload, is a measure of the burden placed on the aquarium ecosystem by its inhabitants. High biological loading presents a more complicated tank ecology, which in turn means that equilibrium is easier to upset. Several fundamental constraints on biological loading depend on aquarium size. The water's limits intake. The bacteria population depends on the physical space they have available to colonize. Physically, only a limited size and number of plants and animals can fit into an aquarium while still providing room for movement. Biologically, biological loading refers to the rate of biological decay in proportion to tank volume. Adding plants to an aquarium will sometimes help greatly with taking up fish waste as plant nutrients. Although an aquarium can be overloaded with fish, an excess of plants is unlikely to cause harm. Decaying plant material, such as decaying plant leaves, can add these nutrients back into the aquarium if not promptly removed. The bioload is processed by the aquarium's filtration system.
4-Nonylphenols and 4-tert-octylphenol in water and fish from ..
Video Collections: Water and Fish | Climate Change Resource Center
The upper Malwathu Oya is a seasonal river. The main livelihood of people living in the immediate vicinity of the river is paddy cultivation, and chronic kidney disease is reported among them. Farmers utilize different types of agricultural chemicals in their fields expecting bumper harvests. Several agricultural chemicals have been reported to contain toxic trace elements in Sri Lanka. Therefore, arsenic and cadmium might end up in the river water. The presence of these trace elements in the river water and sediments can result in their bioaccumulation in fish tissues. The main purpose of this study was to investigate the presence of two trace elements in water and sediments, as well as in fish tissues (gills, kidney, liver and muscle) of three food fish species, Etroplus suratensis, Anabas testudineus and Channa striata during cultivating and non-cultivating seasons of the year. Further, the level of bioaccumulation of two trace elements in fish tissues in relation to the contamination level of water and sediments was assessed. Data were gathered for 43 months. Arsenic and cadmium concentration in water showed a significant (P 0.05) seasonal variation. Generally, the two trace elements in the river water were highest during the cultivating seasons than in other seasons. In all species, both trace elements in the gills highly depended on the concentration in the water. In all species, two trace elements in water and sediment did not significantly affect the levels in muscle tissue. Therefore, the trace element levels in the edible parts of these three fish were well below the maximum permissible levels of international institutions.The pH scale is a scale which is used to measure the acidity or alkalinity of a substance. The scale ranges from 0-14, with 0 being the most acidic, and 14 being the most alkaline. Water with a neutral pH of 7.0 has an equal ratio of H+ ions to OH- ions. Water with a pH below 7.0, is considered acidic (having a more H+ ions than OH- ions), while water with a pH above 7.0 is considered alkaline or basic (having a more OH- ions than H+ ions). Almost all freshwater fish inhabit waters with a pH from 5.0-9.0, with the majority of these inhabiting water with a slightly acidic to neutral pH (6-7.5).