Books about marine life need to be big, like this one, because the sea is a big place and has been occupied for far longer than the land. You’ll learn here that some land creatures have even returned to it, like the ancestors of cetaceans (whales et al), sirenians (dugongs and manatees), and sea-snakes. The saltiness of human blood means that we each carry around a miniature ocean of our own, symbol of our own marine ancestry. The Illustrated World Encyclopedia of Marine Fish and Sea Creatures is an excellent guide to the remainers and the returners of our ancient home. It isn’t a proper scientific encyclopedia, but you can get a good sense of the richness and variety of marine life here, from jellyfish to electric rays by way of the deep-water sea-cucumber, Irpa abyssicola, and the very strange tripod fish, Bathypterois grallator.
That scientific name literally means “the deep-wing stilt-walker”, because the tripod fish lives very deep, up to 3·5km down, and props itself up on extended fin-rays to save energy on swimming. Its tiny prey float towards to it on the current: it isn’t an active hunter. It’s also hermaphroditic, so that each fish can fertilize its own eggs if, thanks to depth and darkness, it doesn’t find a mate. Unlike many other deep-sea fish, however, it isn’t particularly ugly or grotesque and wouldn’t easily find place in an H.P. Lovecraft story. Vampyroteuthis infernalis, or “the vampire squid from hell”, definitely would. It looks rather like an animated umbrella, with dark webs between its tentacles and huge, light-thirsty eyes.
Elsewhere there’s proof that the sea contains not just abysmal ugliness but sublime beauty too, from cone shells (Conus spp.) and jewel “anemones” (Corynactis viridis) (really a form of coral, the book notes) to gorgeous fish like the copperband butterflyfish (Chelmon rostratus) and the Moorish idol (Zanclus cornutus). And the greater blue-ringed octopus (Hapalochlaena lunulata) is beautiful too, despite the “toxin in its saliva estimated to be 10,000 times more deadly than cyanide”. There isn’t enough here about plankton, which can be strange, ugly, and beautiful, but plankton could fill several encyclopedias, and this one does incorporate some more recent scientific discoveries, including the marine life that doesn’t depend ultimately on sunlight, however deep down dark it lives. The giant beardworm, Riftia pachyptila, lives in symbiosis with sulphide-digesting bacteria at hydrothermal vents on the ocean floor. It’s not part of the sun-chain and might have homologues beneath the ice-cap of Jupiter’s moon Europa. Life needs liquid, so far as we can see, and certainly on earth it had to get its start there. This book is an excellent introduction to the great biological cradle that is the sea and would be an ideal gift for a budding marine biologist or scientifically inclined sailer or fisherman.