Ink utilization by mesopelagic squid

Remotely operated vehicle dive video recordings of deep-sea squid ink release were examined to determine species, ink release type, release depth, and accompanying behavior/s. Ink release was commonly observed between the surface and 1,842.1 m in Monterey Bay, CA, and surrounding waters. Six ink release types were observed: pseudomorphs, pseudomorph series, ink ropes, clouds/smokescreens, diffuse puffs and mantle fills. Each species released ink throughout all or most of its depth range; inking was not limited to shallow, sunlit waters. Individuals of each species produced one ink release type more commonly than other types, however, multiple ink types could be released by individuals of all species. Common behaviors preceded and/or followed each release type; pseudomorphs and pseudomorph series were generally associated with escape behaviors, while ink ropes, clouds, and puffs normally involved the animal remaining adjacent to or amid the ink. Deep-sea squids may use ink for defensive purposes similar to those of shallow-dwelling species when they release pseudomorphs, pseudomorph series, or large clouds, and may use ink puffs in intra-specific communication. The function of ink ropes and mantle fills is unknown.