Tours to watch whale sharks, the largest living nonmammalian vertebrate are very popular in La Paz these days, although the price has increased. Due to Covid-19, boats are allowed to carry only half of the passengers they are certified for, a reason to increase the tour prices by aboaut 50 percent. The whale shark is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of 18.8 meters, or about 62 feet.