Toothed whale swallow fishing hooks. Gillnetting and Seine netting are significant causes of mortality in cetaceans and other marine mammals. Porpoises are commonly entangled in fishing nets. Whales are also affected by marine pollution. High levels of organic chemicals accumulate in these animals since they are high in the food chain. They have large reserves of blubber, more so for toothed whales, as they are higher up the food chain than baleen whales. Lactating mothers can pass the toxins on to their young. These pollutants can cause gastrointestinal cancers and greater vulnerability to infectious diseases. They can also be poisoned by swallowing
Toothed belt in their reinforcement. Toothed belts have two failure modes, one gradual and one catastrophic. There is an increased risk of either over the lifetime of the belt, so it is common for highly-stressed belts to be given a service lifetime and to be replaced before this failure can occur. One failure mode is gradual wear to the tooth shape, which may eventually lead to slippage over rounded teeth. The belt often continues to work, but the relative timing between shafts changes. The catastrophic failure mode is caused by delamination between the belt and its fabric reinforcement. Although this may be