Do you believe Pi’s story, or the story that he tells the investigators?

After reading Life of Pi and thinking about the differences between the two stories I am forced to believe that the second story is the true story. Just like the Japanese investigators I find it too difficult to believe that anyone could survive with a tiger in a confined space. Even if Pi was able to train Richard Parker, the tiger's animal instincts would force him to fight Pi for his life before he would let himself starve the way Pi says he did. The natural wonders are also too absurd for me to believe. A swarm of flying fish is a possibility, as this type of fish really do exist, but a drifting island of algae is implausable. While carnivorous algae do exist they are not found in such large colonies as Pi says and don’t change pH levels according to the time of day. The thought of Pi happening upon another castaway in the middle of the Pacific Ocean is another aspect of Pi’s first story that it is difficult for me to believe. The Pacific Ocean is massive and the current that Pi drifted along was very narrow. It is very unlikely that anyone could have found themselves on the same current without Pi noticing as he scanned the horizon. I think that Pi’s second account of his survival is the more likely, believable account but the first account is certainly the better story.