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
Fish drum Fish drum The fish drum () is a Chinese percussion instrument. The name actually designates two rather different instruments, a membranophone and an idiophone. The membranophone fish drum is the symbol of Elder Zhang Guo, one of the Eight Immortals. This drum is a long and slender piece of bamboo with a dried fish skin stretched over one end. Two smaller pieces of bamboo resembling golf clubs are used as Castanets. There is also the idiophone, which is also called a wooden fish. This type of fish drum is used to accompany performers of "changben" or Chinese narrative ballads. They