''Protoblepharon rosenblatti'', the Cook Islands flashlightfish, is a species of flashlight fish found in the waters surrounding the Cook Islands. It can reach lengths of up to and can be found as deep as .

Description

''P. rosenblatti'' was first described in 1997 by Carole C. Baldwin, G. David Johnson and John Richard Paxton and named in honour of the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...

Richard H. Rosenblatt, an expert on the

Anomalopidae Anomalopidae (lanterneye fishes or flashlight fishes) are a family of fish distinguished by bioluminescent organs located underneath their eyes, for which they are named. These light organs contain luminous bacteria and can be "shut off" by the f ...

. The type specimen was brought to the surface by hook and line from a depth of at

Rarotonga Rarotonga is the largest and most populous of the Cook Islands. The island is volcanic, with an area of , and is home to almost 75% of the country's population, with 13,007 of a total population of 17,434. The Cook Islands' Parliament buildings a ...

in the Cook Islands. It has a

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of . The body is deep and laterally compressed, being nearly twice as deep as it is wide. The dorsal fin has 7 spines and 14 soft rays, and the anal fin, 2 spines and 11 soft rays. The eyes are small and there is a small light organ just underneath each eye. This is located on a short stalk and is capable of being rotated downwards so that it is concealed in a pocket which has a stretchable black shutter membrane.

Biology

The light organ underneath the eye of the fish contains

bioluminescent Bioluminescence is the production and emission of light by living organisms. It is a form of chemiluminescence. Bioluminescence occurs widely in marine vertebrates and invertebrates, as well as in some Fungus, fungi, microorganisms including ...

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

bacteria and glows with a strong bluish-green light. It glows all the time, but the flashlight fish can turn it on and off by concealing it in the pocket below the organ which has a black shutter mechanism. The fish are

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

, hiding during the day in caves and dark places at depths of several hundred metres. At night they ascend to near the surface and use the organs to attract their prey, zooplankton, and they also feed on the small fish that are lured by the light to feed on the plankton. The organs are also used by the flashlight fish to confuse their

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

; the flashlight fish can dart away and zigzag repeatedly while alternately displaying and concealing the light.

References

External links

* {{Taxonbar, from=Q2115591 Anomalopidae Taxa named by Carole C. Baldwin Taxa named by G. David Johnson Taxa named by John Richard Paxton Fish described in 1997 Fish of the Pacific Ocean Fauna of the Cook Islands