A novel about species extinction that doesn't really come through

Not a lot to say about Charlotte McConaghy's novel Migrations (2020), which I probably won't finish reading, other than that it's highly ambitious and from what I've read, about 25% of the book, beyond the reach of the writer. The bold ambition: we're in a future world in which many species of animal have vanished and the oceans are so depleted that fishing is outlawed. The narrator and central character is studying one of the few surviving bird species, the Arctic tern, and wrangles a passage from Greenland on one of the few operating fishing boats - and talks the captain into extending the voyage from pole to pole to trace the flight a few tagged terns. The obvious antecedent is Moby-Dick, but this book is not really in Melville's league. the sheer improbability of the venture knocks the plot off the rails, and making matters worse CMcC indulges a # of plot by-ways, including the mystery of the narrator's ancestry, her strange3 marriage, her death wish, and her unexplained (so far) strained relationship w/ the ship's captain. The animal extinction is the premise of the novel, but it's unclear how this happened and what its effect is on human existence: Do farms, for example, continue to exist? How have people survived if so many animals have vanished? Questions and quibbles could go on, but not much point to that; for readers willing to buy into the improbabilities and the narrative hi-jinx, this could be a good read and, who knows?, maybe even a (better?) film.