"The Câmara de Lobos fishermen, also called "Tangerinos" (Tangerines in English) at the time - due to their sun tanned orange complexions, through some inadvertent trial and error, discovered that the Espada fish were best caught - repeatedly and abundantly - at night! That is, at any time when the sun is not shining directly overhead, or when it is heavily overcast or evening. Since the Black Scabbard is considered to be a sedentary fish it showed great economic promise of becoming a very sustainable resource of income and aliment. Unlike its brethren, the White Scabbard, which changed locations across the pelagic at random the Black Scabbard was relatively reliable to catch.
As a natural consequence fishermen sought deeper and further reaches on the high seas to pull their new found prizes away. Fishing nets were useless; special hooks and lines had to be invented. The catching of Espada fish demanded a very long fishing line. Nearly 1,600 metres long! Especially since Espada Preta are “batipelagic” - defined as a species that resides in habitats very deep in the ocean or abysses. Batipelagic depths were once thought to be impossible for fish to survive under due to the incredible sea pressure that any object or thing is subjected to down there."