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Lampris guttatus | |
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Lampris guttatus, conventional and X-ray images | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Lampriformes |
Family: | Lampridae |
Genus: | Lampris |
Species: | L. guttatus |
Binomial name | |
Lampris guttatus | |
Synonyms | |
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Lampris guttatus, commonly known as the opah, cravo, moonfish, kingfish, and Jerusalem haddock, is a large, colorful, deep-bodied pelagic lampriform fish belonging to the family Lampridae, which comprises the genus Lampris .
It is a pelagic fish with a worldwide distribution. While it is common to locations such as Hawaii [3] and west Africa, it remains uncommon in others, including the Mediterranean. [4] In the places where L. guttatus is prevalent, it is not a target of fishing, though it does represent an important commercial component of bycatch. It is common in restaurants in Hawaii. In Hawaiian longline fisheries, it is generally caught in deep nets targeting bigeye tuna. In 2005, the fish caught numbered 13,332. In areas where the fish is uncommon, such as the Mediterranean, its prevalence is increasing. Some researchers believe this a result of climate change. [4] Much is still unknown about the distribution, interactions, life histories, and preferred habitats of this fish and other medium to large-sized pelagic fishes. [5]
Danish zoologist Morten Thrane Brünnich described the species in 1788. The genus name Lampris is derived from the Ancient Greek word lampros, meaning "brilliant" or "clear", while the Latin species name guttatus means "spotted" and refers to the spotted body of this fish. [2]
Although traditionally recognized as one of only two species of opah, the other being the southern opah (L. immaculatus), a review in 2018 found that the widely distributed "L. guttatus" consists of five distinct groups that differ in geographic range, genetics, morphology and meristics: North Atlantic opah (L. guttatus) of the northeast Atlantic including the North Sea and Mediterranean, East Atlantic opah (L. lauta) of the subtropical and warm temperate northeast Atlantic including the Mediterranean, southern spotted opah (L. australensis) of the subtropical and warm temperate Southern Hemisphere, smalleye Pacific opah (L. incognitus) of the central and northeast Pacific, and bigeye Pacific opah (L. megalopsis) found in tropical and subtropical parts of the West Atlantic, Pacific, Indian oceans. [6] [7]
Lampris guttatus is a large discoid and deeply keeled fish with an attractive form and a conspicuous coloration. They can reach a maximum length of 2 m (6.6 ft) and a maximum weight of 270 kg (600 lb). The body is a deep steely blue grading to rosy on the belly, with white spots in irregular rows covering the flanks. Both the median and paired fins are a bright vermillion. Jaws are vermillion, too. The large eyes stand out as well, ringed with golden yellow. The body is covered in minute cycloid scales and its silvery, iridescent guanine coating is easily abraded.
They have long falcated pectoral fins inserted (more or less) horizontally. The caudal fins are broadly lunated, forked, and emarginated. The pelvic fins are similar but a little longer than pectoral fins, with about 14–17 rays. The anterior portion of a dorsal fin (with about 50–55 rays) is greatly elongated, also in a falcate profile similar to the pelvic fins. The anal fin (34–41 rays) is about as high and as long as the shorter portion of the dorsal fin, and both fins have corresponding grooves into which they can be depressed. The snout is pointed and the mouth small, toothless, and terminal. The lateral line forms a high arch over the pectoral fins before sweeping down to the caudal peduncle.
In May 2015, L. guttatus was shown to maintain its entire body core above ambient temperature, becoming the first known fish with this trait ('whole-body endothermy'). [8] [9] The fish generates heat as well as propulsion with continuous movements of its pectoral fins (the musculature of which is insulated by a one-cm-thick layer of fat), and the vasculature of its gill tissue is arranged to conserve heat by a process of countercurrent heat exchange, a structure known as a rete mirabile (plural, retia). [8] [10] It can consistently keep its body core approximately 5 °C warmer than its environment. [9] Elevated body core temperature should improve aerobic performance and physiologic function. Other adaptions of L. guttatus to increase aerobic performance include high hematocrit and a relatively large heart, gill surface area and aerobic muscle mass. These adaptations for high performance predation are similar to those found in tuna and lamnid sharks, which actively chase down their prey, but are very unusual among lampridiform fish, which are mostly sluggish ambush predators. [8]
Previously, L. guttatus was known to exhibit cranial endothermy, generating and maintaining metabolic heat in the cranial and optic regions to keep them 2 °C warmer than the rest of the body. [11] This adaptation is important for maintaining brain and eye function during the wide range of temperatures it experiences with its vertical movements. [12]
Most fish are completely cold-blooded. Some, such as tuna [13] and lamnid sharks (such as the salmon shark [14] ), have evolved regional endothermy, in which parts of the body core are kept at a warmer temperature. These fish have retia arranged to warm muscles used for propulsion, and some visceral organs, while other organs, such as the heart, remain cooler. [8] [9] Only L. guttatus is known to have retia within its gill arches (which are also insulated by fat), an arrangement that warms the entire body core including the heart. [8] [15]
Lampris guttatus has a worldwide distribution, from the Grand Banks to Argentina in the Western Atlantic, from Norway and Greenland to Senegal and south to Angola in the Eastern Atlantic (also in the Mediterranean), from the Gulf of Alaska to southern California in the Eastern Pacific, in temperate waters of the Indian Ocean, and rare forays into the Southern Ocean. [2]
This species is presumed to live out its entire life in the open ocean, at mesopelagic depths of 50–500 m (160–1,640 ft), with possible forays into the bathypelagic zone. Typically, it is found within water at 8 to 22 °C. [3] To better understand the depths L. guttatus inhabited in the tropical and temperate ocean waters, a study was performed, tagging them in the central North Pacific. Their location was found to be related to a temporal scale, inhabiting depths of 50–100 m during the night and 100–400 m during the day. The depths of the vertical habitat varied with local oceanogeographic conditions, though the patterns of deeper depths during the day is universal to the species. [5]
The endothermy of Lampris guttatus gives them a major advantage at the depths where they live. Since they are relatively warm-blooded at those depths compared to the water around them, they can move more quickly to hunt prey. Most predators at such low depths do not have the energy to be able to move much and therefore must wait for prey to pass them. [8]
The life history and development of L. guttatus remains rather uncertain. [16] They are apparently solitary, but are known to school with tuna and other scombrids. They propel themselves by a lift-based mode of swimming using their pectoral fins. This, together with their forked caudal fins and depressible median fins, indicates that they swim at constantly low speeds. They are able to swim at over 25 cm/s, and one was even observed reaching 4 m/s in a burst of speed. [3]
Like many other large pelagic visual predators, such as swordfish and big-eye tuna, they exhibit vertical behavior.[ further explanation needed ] Based on those caught off the Hawaiian coast, squid and krill make up the bulk of their diet, though they also consume small fish. Those caught along the Patagonian Shelf also showed a narrow range of prey, the most common of which was the deepwater onychotenhid squid ( Moroteuthis ingens ). [3]
They probably spawn in the spring. [2] Their planktonic larvae lack dorsal and pelvic fins. The slender hatchlings undergo a marked and rapid transformation from a slender to deep-bodied form; this transformation is complete by 10.6 mm standard length.
Osteichthyes, also known as osteichthyans or commonly referred to as the bony fish, is a diverse superclass of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes and the extinct placoderms and acanthodians, which have endoskeletons primarily composed of cartilage. The vast majority of extant fish are members of Osteichthyes, being an extremely diverse and abundant group consisting of 45 orders, over 435 families and 28,000 species. It is the largest class of vertebrates in existence today, encompassing most aquatic vertebrates, as well as all semi-aquatic and terrestrial vertebrates.
Lampriformes is an order of ray-finned fish. Members are collectively called lamprids or lampriforms, and unite such open-ocean and partially deep-sea Teleostei as the crestfishes, oarfish, opahs, and ribbonfishes. A synonym for this order is Allotriognathi, while an often-seen, but apparently incorrect, spelling variant is Lampridiformes. They contain seven extant families which are generally small but highly distinct, and a mere 12 lampriform genera with some 20 species altogether are recognized. They are the only extant members of the superorder Lamprimorpha, which was formerly diverse throughout much of the Late Cretaceous.
A rete mirabile is a complex of arteries and veins lying very close to each other, found in some vertebrates, mainly warm-blooded ones. The rete mirabile utilizes countercurrent blood flow within the net to act as a countercurrent exchanger. It exchanges heat, ions, or gases between vessel walls so that the two bloodstreams within the rete maintain a gradient with respect to temperature, or concentration of gases or solutes. This term was coined by Galen.
The albacore, known also as the longfin tuna, is a species of tuna of the order Scombriformes. It is found in temperate and tropical waters across the globe in the epipelagic and mesopelagic zones. There are six distinct stocks known globally in the Atlantic, Pacific, and Indian oceans, as well as the Mediterranean Sea. The albacore has an elongate, fusiform body with a conical snout, large eyes, and remarkably long pectoral fins. Its body is a deep blue dorsally and shades of silvery white ventrally. Individuals can reach up to 1.4 m in length.
The silky shark, also known by numerous names such as blackspot shark, gray whaler shark, olive shark, ridgeback shark, sickle shark, sickle-shaped shark and sickle silk shark, is a species of requiem shark, in the family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge of the continental shelf down to 50 m (164 ft). The silky shark has a slender, streamlined body and typically grows to a length of 2.5 m. It can be distinguished from other large requiem sharks by its relatively small first dorsal fin with a curving rear margin, its tiny second dorsal fin with a long free rear tip, and its long, sickle-shaped pectoral fins. It is a deep, metallic bronze-gray above and white below.
The Atlantic bluefin tuna is a species of tuna in the family Scombridae. It is variously known as the northern bluefin tuna, giant bluefin tuna [for individuals exceeding 150 kg (330 lb)], and formerly as the tunny.
The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.
The porbeagle or porbeagle shark is a species of mackerel shark in the family Lamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. In the North Pacific, its ecological equivalent is the closely related salmon shark (L. ditropis). It typically reaches 2.5 m (8.2 ft) in length and a weight of 135 kg (298 lb); North Atlantic sharks grow larger than Southern Hemisphere sharks and differ in coloration and aspects of life history. Gray above and white below, the porbeagle has a very stout midsection that tapers towards the long, pointed snout and the narrow base of the tail. It has large pectoral and first dorsal fins, tiny pelvic, second dorsal, and anal fins, and a crescent-shaped caudal fin. The most distinctive features of this species are its three-cusped teeth, the white blotch at the aft base of its first dorsal fin, and the two pairs of lateral keels on its tail.
Lancetfishes are large oceanic predatory fishes in the genus Alepisaurus in the monogeneric family Alepisauridae.
Opahs, also commonly known as moonfish, sunfish, kingfish, and redfin ocean pan are large, colorful, deep-bodied pelagic lampriform fishes comprising the small family Lampridae.
Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs.
The bigeye tuna is a species of true tuna of the genus Thunnus, belonging to the wider mackerel family Scombridae. In Hawaiian, it is one of two species known as ʻahi, the other being the yellowfin tuna. Bigeye tuna are found in the open waters of all tropical and temperate oceans, but not in the Mediterranean Sea.
The common thresher, also known as Atlantic thresher, is the largest species of thresher shark, family Alopiidae, reaching some 6 m (20 ft) in length. About half of its length consists of the elongated upper lobe of its caudal fin. With a streamlined body, short pointed snout, and modestly sized eyes, the common thresher resembles the pelagic thresher. It can be distinguished from the latter species by the white of its belly extending in a band over the bases of its pectoral fins. The common thresher is distributed worldwide in tropical and temperate waters, though it prefers cooler temperatures. It can be found both close to shore and in the open ocean, from the surface to a depth of 550 m (1,800 ft). It is seasonally migratory and spends summers at lower latitudes.
The longfin mako shark is a species of mackerel shark in the family Lamnidae, with a probable worldwide distribution in temperate and tropical waters. An uncommon species, it is typically lumped together under the name "mako" with its better-known relative, the shortfin mako shark. The longfin mako is a pelagic species found in moderately deep water, having been reported to a depth of 220 m (720 ft). Growing to a maximum length of 4.3 m (14 ft), the slimmer build and long, broad pectoral fins of this shark suggest that it is a slower and less active swimmer than the shortfin mako.
The pelagic thresher is a species of thresher shark, family Alopiidae; this group of sharks is characterized by the greatly elongated upper lobes of their caudal fins. The pelagic thresher occurs in the tropical and subtropical waters of the Indian and Pacific Oceans, usually far from shore, but occasionally entering coastal habitats. It is often confused with the common thresher, even in professional publications, but can be distinguished by the dark, rather than white, color over the bases of its pectoral fins. The smallest of the three thresher species, the pelagic thresher typically measures 3 m (10 ft) long.
The pelagic stingray is a species of stingray in the family Dasyatidae, and the sole member of its genus. It is characterized by the wedge-like shape of its pectoral fin disc, which is much wider than long, as well as by the pointed teeth in both sexes, whip-like tail with extremely long tail spine, and uniform violet to blue-green coloration. It generally reaches 59 cm (23 in) in width. The pelagic stingray has a worldwide distribution in waters warmer than 19 °C (66 °F), and migrates seasonally to spend the summer closer to the continental shelf and at higher latitudes. The only stingray that almost exclusively inhabits the open ocean, this species is typically found in surface waters down to a depth of 100 m (330 ft). As a consequence of its midwater habits, its swimming style has evolved to feature more of a flapping motion of the pectoral fins, as opposed to the disc margin undulations used by other, bottom-dwelling stingrays.
The Pacific bluefin tuna is a predatory species of tuna found widely in the northern Pacific Ocean, but it is migratory and also recorded as a visitor to the south Pacific.
The little tunny, also known as the false albacore, little tuna, bonita, or erroneously as the blue bonito, is a species of tuna in the family Scombridae. It can be found in the Atlantic Ocean and the Mediterranean and Black seas; in the western Atlantic, it ranges from Brazil to the New England states. The little tunny is a pelagic fish that can be found regularly in both offshore and inshore waters, and it is classified as a highly migratory species. The little tunny is best identified by the "worm-like" markings on its back and the dark spots appearing between its pectoral and ventral fins.
Predatory fish are hypercarnivorous fish that actively prey upon other fish or aquatic animals, with examples including shark, billfish, barracuda, pike/muskellunge, tuna, dolphinfish, walleye, perch and salmon. Some omnivorous fish, such as the red-bellied piranha, can occasionally also be predatory, although they are not strictly regarded as obligately predatory fish.
Chilomycterus reticulatus, the spotfin burrfish, spotted burrfish, Pacific burrfish, spotfin porcupinefish or few-spined porcupinefish, is a species of fish in the genus Chilomycterus, which is part of the porcupinefish family Diodontidae.