User:Gummycrown/Giant oarfish

Life Cycle
Much of what we know about the juvenile life cycle of R. glesne comes from artificial insemination work done in a laboratory setting. This work was done in 2020 and is the first time that the cycle from fertilized eggs to larvae was observed. This study used individuals bred and raised in captivity, and began with the artificial insemination of two recently deceased individuals that died upon capture.

Post-fertilization, the eggs took 18 days to hatch into larvae. They noted that the larvae appeared similar to other lampridiform larvae, facing downward with pectoral fins. The larvae then died four days later, so this study remains a look into the early life cycle, as these individuals did not reach maturity.

Description
This species is the world's longest bony fish, reaching a record length of 8 m; however, unconfirmed specimens of up to 11 m have been reported. It is commonly measured to 3 m in total length. The maximum recorded weight of a giant oarfish is 270 kg.

Its shape is ribbonlike, narrow laterally, with a dorsal fin along its entire length from between its eyes to the tip of its tail. The fin rays are soft and may number up to 400 or more. At the head of the fish, the rays are lengthened forming a distinctive red crest. Its pectoral and pelvic fins are nearly adjacent. The pectoral fins are stubby while the pelvic fins are long, single-rayed, and reminiscent of an oar in shape, widening at the tip. Its head is small with the protrusible jaw typical of lampriformes; it has 40 to 58 gill rakers, and no teeth.

The organs of the giant oarfish are concentrated toward the head end of the body, possibly enabling it to survive losing large portions of its tail. It has no swim bladder. The liver of R. glesne is orange or red, the likely result of astaxanthin in its diet. The lateral line begins above and behind the eye then, descending to the lower third of the body, extends to the caudal tip.

The skin of R. glesne is scaleless but covered with tubercles. The skin color is silver with streaks, spots or splotches of black or dark gray, and a bluish or brownish tinge on the head. Its fins, including its long dorsal fin and crest, are red, again probably resulting from its diet.

Article (Original)
The giant oarfish (Regalecus glesne) is a species of oarfish of the family Regalecidae. It is an oceanodromous species with a worldwide distribution, excluding polar regions. Other common names include Pacific oarfish, king of herrings, ribbonfish, and streamer fish.

R. glesne is the world's longest bony fish. Its shape is ribbon-like, narrow laterally, with a dorsal fin along its entire length, stubby pectoral fins, and long, oar-shaped pelvic fins, from which its common name is derived. R. glesne 's head and body is silver and blue with spots of dark coloration, and its fins are crimson. Its physical characteristics and its undulating mode of swimming have led to speculation that it might be the source of many "sea serpent" sightings.

Distribution
The giant oarfish has a worldwide distribution, having been found as far north as 72°N and as far south as 52°S. However, the species is most commonly found in the tropics to middle latitudes. It is thought to inhabit the sunlit epipelagic to dimly lit mesopelagic zones, ranging as deeply as 1000 m below the surface.

Description
This species is the world's longest bony fish, reaching a record length of 8 m; however, unconfirmed specimens of up to 11 m have been reported. It is commonly measured to 3 m in total length.

Few R. glesne larvae have been identified and described in situ. These larvae exhibit an elongated body with rays extending from the occipital crest and a long pelvic fin. Unlike the adult form of the species, the skin of the larvae is almost entirely transparent with intermittent spots of dark coloring along the organism's dorsum. Additionally, the larvae possess a caudal fin with four fin rays, which is a trait not present in the adult form of the species.

Adults have a ribbonlike shape that is laterally narrow, with a dorsal fin along its entire length from between its eyes to the tip of its tail. The dorsal fin rays are soft and number between 414 and 449 in total. At the head of the fish, the first 10-12 of these dorsal fin rays are lengthened, forming the distinctive red crest associated with the species. Its pectoral and pelvic fins are nearly adjacent. The pectoral fins are stubby while the pelvic fins are long, single-rayed, and reminiscent of an oar in shape, widening at the tip. Its head is small with the protrusible jaw typical of lampriformes. The species has 33 to 47 gill rakers on the first gill arch, and no teeth.

The organs of the giant oarfish are concentrated toward the head end of the body, possibly enabling it to survive losing large portions of its tail. It has no swim bladder. The liver of R. glesne is orange or red, the likely result of astaxanthin in its diet. The lateral line begins above and behind the eye then, descending to the lower third of the body, extends to the caudal tip.

Behavior
Little is known about oarfish behavior. It has been observed swimming by means of its dorsal fin, and also swimming in a vertical position. In 2010, scientists filmed a giant oarfish in the Gulf of Mexico swimming in the mesopelagic layer, the first footage of a reliably identified R. glesne in its natural setting. The footage was caught during a survey, using an ROV in the vicinity of Thunder Horse PDQ, and shows the fish swimming in a columnar orientation, tail downward.

It feeds on krill and other small crustaceans, as well as small fish and squid. It is known to spawn from July to December. The eggs are 2.5 mm large, and float near the surface until hatching. Its larvae are also observed near the surface during this season. As an adult, it is believed to be solitary.

Relationship with humans
R. glesne is not fished commercially, but it is an occasional bycatch in commercial nets, and as such it has been marketed.

Because they are not often seen and because of their size, elongated bodies, and appearance, giant oarfish are presumed to be responsible for some sea serpent sightings. Formerly considered rare, the species is now suspected to be comparatively common, although sightings of healthy specimens in their natural habitat are unusual.

The giant oarfish and the related R. russelii are sometimes known as "earthquake fish" because they are popularly believed to appear before and after an earthquake.