Juveniles and sub adults live and migrate in open water at shallow to moderate depths. They move to the bottom as adults when they settle around sea mounts in the North Pacific.
Observation by Edgar Smith:
This fish was caught in a purse seine at Jack Point near Chignik Alaska. The markings appear to be tropical.
Andrés López, Curator of Fish with the University of Alaska Museum, writes:
I am thinking it is a slender armorhead (Pentaceros wheeleri) subadult. See Figure 1B in the attached article. It makes sense based on location of the observation and the color pattern. P.S. Any chance the fish is still in somebody's freezer? 9-18-19
Comment by Edgar Smith:
No it’s not in a freezer. It was still alive and was released back into the water as soon as possible. I’ve asked around here if anyone has seen something like it before and we really couldn’t find anyone that knows what it may be. Thanks for looking into it. 9-18-19
Tom Okey with Ocean Integrity Research writes:
Just based on my perusal of the species profile on Fishbase, it doesn't seem like that much is known about this species, perhaps because of their stated depth range (146-800 m)(Fadeev 2005), which is a heck of a lot deeper than a purse-seine net. However, Andres indicated it is a sub-adult, and so more epipelagic (the photosynthetic zone). Still, it would be good to get more info on how unusual this species is for different fishing gear types to encounter. One way to check would be a post on the Facebook group 'Unusual Marine Life of Alaska'. Another would be for a NMFS insider to query the fishery observer database, which might well contain some pretty interesting information about this species. 9-18-19
Fadeev, N.S., 2005. Guide to biology and fisheries of fishes of the North Pacific Ocean. Vladivostok, TINRO-Center. 366 p.
Andrés López writes:
According to the article attached, the juveniles and subadults live and migrate in open water at shallow to moderate depths. They only move to the bottom as adults when they settle around sea mounts in the North Pacific. Below is the full citation for that article. It includes quite a bit of what is known about the biology of the species. This observation was a great motivator to learn about a fish I knew nothing about prior! 9-19-19
Kiyota, Masashi, Kazuya Nishida, Chisato Murakami, and Shiroh Yonezaki. 2016. “History, Biology, and Conservation of Pacific Endemics 2. The North Pacific Armorhead, Pentaceros Wheeleri (Hardy, 1983) (Perciformes, Pentacerotidae).” Pacific Science 70 (1): 1–20.
Comment from LEO Editors:
This is the first report on a Slender Armorhead received in LEO Network. An unusual fish for Chignik Lake for sure but within its general range, which according to FishBase is "Gulf of Alaska to North Pacific Ocean off central California and south of Japan, with center of abundance at the seamounts of the southern Emperor-northern Hawaiian Ridge." See a species profile here at FishBase. Mike Brubaker
Pentaceros
