Often avoiding sampling gear with their capability to detect movements and swim their way out of the nets fast enough, the small squids living in the open-ocean zone have so long gone under-researched. The present study, conducted by Dr. Michel Hendrickx, Universidad Nacional Autonoma de Mexico, and his team, seems to provide new and first distributional records of five such species for the Gulf of California and in southwestern Mexico. It also significantly expands the currently known southernmost limit of localities of some of these squids in the eastern Pacific. The research is available in the open-access journal ZooKeys.
The researched five squid species belong to two genera, Abraliopsis and Pterygioteuthis, which although abundant and diverse, have long been shrouded by taxonomic and distributional controversies. To solve them, the researchers used specimens, collected over the span of thirteen years, comprising eight cruises across 113 locations in the Gulf of California and off the southwestern coast of Mexico.
As a result, the scientists concluded a significantly wider distributional range of the species they found. For instance, squids of the Abraliopsis genus were surprisingly found in water deeper than 600 m during the day.
The studied small squids are of high ecological value due to their vital position in the food web. Members of Abraliopsis are important preys for many fishes and mammals, such as the peruvian hake, the Indo-Pacific sailfish, the common dolphinfish and the local sharks. Meanwhile, the representatives of the other researched genus, Pterygioteuthis, are often consumed by larger cephalopods, sea-birds and fur seals. However, their abundance is strongly dependent on temperature, especially when there are fast and significant changes.
The scientists suggest that additional samplings with more adequate equipment, like faster large-sized mid-water trawls, could further bridge the knowledge gaps about these elusive marine inhabitants.
Hendrickx ME, Urbano B, Zamorano P (2015) Distribution of pelagic squids Abraliopsis Joubin, 1896 (Enoploteuthidae) and Pterygioteuthis P. Fischer, 1896 (Pyroteuthidae) (Cephalopoda, Decapodiformes, Oegopsida) in the Mexican Pacific. ZooKeys 537: 51-64. doi: 10.3897/zookeys.537.6023.