Search results
Results from the WOW.Com Content Network
Copper–nickel alloys for marine applications are usually 90% copper, 10% nickel, and small amounts of manganese and iron to enhance corrosion resistance. The seawater corrosion resistance of copper–nickel alloys results in a thin, adherent, protective surface film which forms naturally and quickly on the metal upon exposure to clean seawater.
HLLE begins as small pits of receding epithelium (skin) around the fish's head and/or lateral line, and sometimes onto the unpaired fins. Rarely fatal, it does cause disfigurement, making the fish less suitable for public aquarium display. At least 20 families of fish have been identified as having developed HLLE in captivity.
The use of copper sheathing was first suggested by Charles Perry in 1708, though it was rejected by the Navy Board on grounds of high cost and perceived maintenance difficulties. The first experiments with copper sheathing were made in the late 1750s: the bottoms and sides of several ships' keels and false keels were sheathed with copper plates ...
The copper performed well in protecting the hull from invasion by worm, and in preventing the growth of weed, for when in contact with water, the copper produced a poisonous film, composed mainly of oxychloride, that deterred these marine creatures. Furthermore, as this film was slightly soluble, it gradually washed away, leaving no way for ...
If disease occurs eradication is required. Once the disease is eradicated, good husbandry, surveillance and biosecurity measures are necessary to prevent recurrence. In countries free of epizootic ulcerative syndrome, quarantine and health certificates are necessary for the movement of all live fish to prevent the introduction of the disease.
One of the more bizarre and recently discovered diseases produces huge fish kills in shallow marine waters. It is caused by the ambush predator dinoflagellate Pfiesteria piscicida . When large numbers of fish, like shoaling forage fish , are in confined situations such as shallow bays, the excretions from the fish encourage this dinoflagellate ...
Columnaris disease in young fish is acute and damages the gills, leading to death by respiratory distress. [1] In chronic cases, fin rot , or frayed and ragged fins, can appear. These begin at the base of the dorsal fin on the back of a fish and spread over time, hence the name saddleback disease . [ 3 ]
Salt is the most effective bath treatment, and is used to eliminate ciliated protozoan parasites (including ich in small fish); also used to curb the absorption of nitrite, and to reduce the osmotic pressure exerted by fresh-water on any hole in the skin or gill. Potassium permanganate and ionic copper are used to treat similar ailments.