Fish kill dead zones in the gulf are mainly created by the nitrogen and phosphorus enrichment of the Lower Mississippi River. Some species of fish exhibit mass simultaneous mortality as part of their natural life cycle. Fish kill due to spawning fatalities can occur when fish are exhausted from spawning activities such as courtship, nest building, and the release of eggs or milt (sperm). Fish are generally weaker after spawning and are less resilient than usual to smaller changes in the environment. Examples include the Atlantic salmon and the Sockeye salmon where many of the females routinely die immediately after spawning. A
Wooden fish can differ amongst wooden fish depending on the size, type of wood used, and how hollow the wooden fish is. The instrument is carved with fish scales on its top, and a carving of two fish heads embracing a pearl on the handle (to symbolize unity), hence the instrument is called a wooden fish for that reason. In Buddhism the fish, which never sleeps, symbolizes wakefulness. Therefore, it is to remind the chanting monks to concentrate on their sutra. Often the mallet used to strike the fish has a rubber coated tip to provide a muffled, but clear sound when