what causes asian carp to jump out of the water
Asian carp Silver carp have become notorious for being easily frightened by boats and personal watercraft, which cause them to leap high into the air. The fish can jump up to 2.5–3.0 m (8–10 ft) into the air, and numerous boaters have been severely injured by collisions with the fish.[3] According to the EPA, "reported injuries include cuts from fins, black eyes, broken bones, back injuries, and concussions.".[4] Silver carp can grow to 45 kg (100 lb) in mass.[5] This behavior has sometimes also been attributed to the very similar bighead carp, but this is uncommon. Bighead carp do not normally jump when frightened.[1] Catching jumping carp in nets has become part of the Redneck Fishing Tournament, in Bath, Illinois.[6] Other parties, such as the Peoria Carp Hunters, have taken advantage of the jumping ability as a mechanism of hunting the carp, in some cases to purge the invasive species.[7]
Mercury in fish The consumption of fish is by far the most significant source of ingestion-related mercury exposure in humans and animals.[4] Mercury and methyl mercury are present in only very small concentrations in seawater. However, they are absorbed, usually as methyl mercury, by algae at the start of the food chain. This algae is then eaten by fish and other organisms higher in the food chain. Fish efficiently absorb methyl mercury, but excrete it very slowly.[5] Methyl mercury is not soluble and therefore not excreted. Instead, it accumulates, primarily in the viscera, although also in the muscle tissue.[6] This results in the bioaccumulation of mercury, in a buildup in the adipose tissue of successive trophic levels: zooplankton, small nekton, larger fish, and so on. The older that such fish become, the more mercury they may have absorbed. Anything that eats these fish within the food chain also consumes the higher level of mercury that the fish have accumulated. This process explains why predatory fish such as swordfish and sharks or birds like osprey and eagles have higher concentrations of mercury in their tissue than could be accounted for by direct exposure alone. Species on the food chain can amass body concentrations of mercury up to ten times higher than the species they consume. This process is called biomagnification. For example, herring contains mercury levels at about 0.1 parts per million, while shark contains mercury levels greater than 1 part per million.[7]