Sockeye salmon natural selection against large bodies. Populations with higher levels of predation tend to evolve smaller body size. Without the threat of predation, salmon that breed early in the season live longer than those that breed late in the season. Other ecological factors like stranding effect select for smaller body size in sockeye salmon when present in a habitat. Stranding is when salmon swim into dry land or shallow water during their migration for spawning and die from suffocation. In fact, studies show that the Sockeye salmon with the largest bodies are most susceptible to stranding mortality. Reproduction is marked by
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