hic sunt dracones

Via the always interesting Languagehat not only do we learn that there is a cooperative effect to document and propagate a lexical database of marine life, said lexicon also covers chimera and mythical beings, revealing that merfolk also include the merbishop (unclear whether that is due to appearance or ecclesiastical hierarchy), an anthropomorphic fish described by Cornelius Aurelius in 1517 and revisited by renowned Swiss naturalist and regarded as the father of zoology Conrad Gessner in 1604—exemplars along with mermonks (moine de mer, Seemönch, pesce monaco) captured in the Baltic Sea. Much more to explore at the links above—including an impressively comprehensive, non-sea-life glossary of boat-building terminology.