A gregarious harbor porpoise gains an expanded circle of land-based friends and allies in this sequel to A Dog's Porpoise (2019).Into this second wholesome, joyfully splashy episode, the pun-loving author folds both sober concerns about the hazards of human–wild animal interactions and a cautionary subplot about being too quick to judge others. Lars the dog is delighted to dive in with Natalie, his adopted human, to play with finny, friendly harbor porpoise Bangor. But a likewise playful river otter, soon dubbed "Marina" by charmed observers, arrives to replace him as the center of attention. Worse yet (from Natalie's point of view, anyway), the furry new visitor brings not only a fresh flood of reporters and tourists to sleepy Ogunquit, Maine, but also a standoffish stranger, formerly associated with an abusive roadside animal attraction, who asks ominously sharp questions about exactly where the otter and Bangor's family pod are most often spotted. As it turns out, the stranger's motives are actually benign, and no sooner does he voice warnings about how being too comfortable around humans can place wild animals in danger than Bangor is wounded in a collision with a boat and beached. This crisis sets the stage for both a dramatic rescue (in which even Lars and the otter play important roles) and better relations all round. The mildly anthropomorphic creature cast is joined by a human one that's cued white.Aswim with good feelings and cogent points to ponder. (Fiction. 8-11)