WWE Star Shad Gaspard

WWE Star Shad Gaspard's widow claims the Venice Beach lifeguards on duty the day her husband died left him to fend for himself ... and she wants L.A. and California to pay for her loss.

Siliana Gaspard filed a wrongful death suit ... alleging the lifeguards weren't up to snuff in protecting Shad from drowning, which she says happened on the government's watch.

In her docs, obtained by TMZ, Siliana claims there wasn't sufficient signage on Venice Beach the day Shad died to warn him of the dangers of strong currents with the potential to take him under.

Not only that, but she claims the lifeguard towers that day were significantly understaffed and the lifeguards negligently opted to only save…