Answer:
To determine the time of death, I would perform a thorough examination of the remains, including the foot and leg that were regurgitated by the shark, as well as any other remains found in the shark's belly. I would look for signs of rigor mortis and livor mortis, as well as the state of decomposition, which can give an estimate of how long the body has been in the water. I would also perform a toxicology test to determine if there were any drugs or other substances in the body that may have contributed to the man's death.
In terms of the stage of decomposition, I would examine the body for signs of putrefaction, including the presence of gases and liquefaction of the tissues, as well as the presence of insect activity. This information, combined with the temperature of the water and other environmental conditions, can help to determine the rate of decomposition and the stage of decomposition that the body was in when it was eaten by the shark.
Based on the information available, it is most likely that the man died from some cause other than being attacked by the shark, and that his body was subsequently consumed by the shark after death. This is a common behavior among Tiger Sharks, which are known to scavenge on dead animals and human remains that are present in the ocean. However, without further investigation, it is impossible to say for certain what happened to the man in this case.