The Devil Fish — Geoffrey T. Williams

Twins Alena and Tyler Worthy, their trusty terrier Brutus, and friend Xochitl-track a pair of magnificent giant manta rays from Mexico's Sea of Cortez to the islands off the coast of Baja California. A deadly drift net near one of the islands threatens the mantas who are heading straight for it. The team needs every bit of courage, ingenuity, intelligence, and technology-plus help from a very surprising source if they hope to escape.