If the streak is a contrail, then it would disappear over the horizon rather than ending at the flash unless a jet crashed into the water.
If the event is a bulb burning out, then why would there be a shock wave to one side? The layman in me would expect, if anything, a uniform distribution of debris moving away from the lamp-post shield.
The bug theory seems to rely on a flash. Did the photographer say he used a flash?
Doesn't this point to a projectile? If so, perhaps the bulb in question was already burned out.
A side note is that the boat to the right of the pier moves in the sequence of images from right to left with barely a wake. Does this help corroborate the timeframe and alleviate suspicion of tampering? (i.e. That ought to be difficult to fake realistically)
Another side note are the 80 beached whales in Tasmania 4 days later. Perhaps someone was interested enough to send a sub with high-decibel sonar to investigate this story? Combine that with interest from NASA and I'd say inquiring minds want to know what this is.