Scophthalmidae

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Scophthalmidae
Psetta maxima.JPG
Scophthalmus maximus
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Superorder: Acanthopterygii
Clade: Percomorpha
Order: Pleuronectiformes
Family: Scophthalmidae
Chabanaud, 1933
Type genus
Scophthalmus
Rafinesque, 1810
Genera [1]

Lepidorhombus
Phrynorhombus
Scophthalmus
Zeugopterus

Contents

The Scophthalmidae are a family of flatfish found in the North Atlantic Ocean, Baltic Sea, Mediterranean Sea, and Black Sea. [2] Fish of this family are known commonly as turbots, [1] [3] though this name can refer specifically to Scophthalmus maximus , as well. Some common names found in species of this family are turbots, windowpanes, and brills. [4]

Cladistic analysis reveals that this family is a monophyletic group. [2]

Of all the scophthalmids, the largest species ( Scophthalmus maximus ) reaches approximately one meter in length. [4] Some species in the family have been historically fished commercially (predominantly the brill flatfish and the turbot flatfish, S.rhombus and S. maximus respectively). [2]

Taxonomy

The Scophthalmidae family is composed of two main clades, four genera, and eight species. [4] The four genera are Zeugopterus, Lepidorhombus, Phrynorhombus, and Scophthalmus, all sharing synapomorphies yet also subtle distinctions. [2] [4]

Discovery

The first known fossil was dated to the Cenozoic era during the Miocene epoch. This specific fossil is believed to be from the upper Tertiary and is the oldest specimen of the family. [5]

Taxonomic history

Distribution and habitat

Turbots are benthic animals and can be found in both Marine and Brackish environments, but not in freshwater. [4] While certain flatfish can be found in the other regions, Scophthalmidae are native to the North Atlantic, as well as the Baltic, Mediterranean, and Black seas. [2] [4] According to Fishes of the Word and excluding one species located in the Western Atlantic, all other scophthalmids reside in the general Northeastern Atlantic region. [4] However, mapping out a specific organism's changes in habitat over their lifespan would be rather complex. Environmental events can displace fish or incline them to leave their home ranges. All fishes, including scophthalmids, also face predation risks and prey scarcity, as well as the complexities of spawning behaviors. While true, movements of the species can be tracked for instances of displacement as well as seasonal cycles of migration–both of which “appear to be triggered by changes in water temperature, light, current velocity, and irregular episodic events.” [6]

Scophthalmus maximus in front of a thornback ray (Raja clavata) at the Scarborough SEA LIFE Sanctuary in England. Hal - Scophthalmus maximus - 3.jpg
Scophthalmus maximus in front of a thornback ray(Raja clavata) at the Scarborough SEA LIFE Sanctuary in England.

The movement of water is crucial to the species as it is a primary form of transportation. [7] All stages of the flatfish (from larval, juvenile, to adult) use the elliptic and cyclic nature of Earth's tides in locomotion. The rising tide carries individuals shoreward and during the ebb tide they can exit the water column and sink to the bottom. This is crucial to energy expenditure, especially in migratory events between feeding and spawning grounds that take place every year. [6] During migrations tidal cycles are primary in determining the vertical displacement of flatfish in the water column, while on feeding and spawning grounds these behaviors are more influenced by the diel cycle. The location of turbots is cryptic and multivariable, consisting of a mixture of both these cycles, an internal “clock” mechanism, and other factors such as turbulence, hunger, and magnetic fields. [6]

But with all said and done, the flatfish don't go too far. The anatomy of these organisms is intrinsically negatively buoyant, [6] making them sink in the absence of currents and upwellings. To preserve energy, this is their natural state. They are rather sedentary and the fish spend most of their time on bottom substrates. [3] [4] [6]

Anatomy and morphology

Turbots (Pictured) FMIB 49965 Turbots.jpeg
Turbots (Pictured)

Scophthalmidae is a family of ray-finned fish ( Actinopterygii ), so it exhibits any primitive traits of that clade. Being a scientific family, it also has its own set of general traits, as well as a variety of derived traits specific to the different genera of Scophthalmidae. These various features can be distinguished at every level of the scientific hierarchy to best emphasize the differences between the taxon. Being part of the Scophthalmidae family, all scophthalmids share the same fundamental Actinopterygii and pleuronectiformes traits.

Actinopterygii traits

Actinopterygii, or ray-finned fish, share traits will all prior marine vertebrates (i.e. a skeleton, paired fins, cycloid or ctenoid scales, covered gills, homocercal tails, protrusible jaws, etc...) [8] The main requirements for the taxa are fin-rays (of which make up the fins and are responsible the name of the clade) and a swim bladder (a derived trait of this phylogenetic group). [5] All genera of Scophthalmidae are Actinopterygii, and as such share this primary features.

Pleuronectiformes traits

Pleuronectiformes (flatfish) share a lot in common with some minor distinctions. Based on the name, it is right to assume that most of genera of pleuronectiformes are 'flat' and have a generally 'low' body profile. Due to this anatomical difference, flatfish are quite unique and have asymmetrical features. In adult individuals, both eyes lye on the same side of the head on whichever side is dominant (Scophthalmidae are left-eyed flatfish). Furthermore, flatfish have protrusible eyes and have slowly translated their dorsal fin (over the course of evolutionary history) onto the head. [3] [4] Poking eyes out of the substrate and using this dorsal fin akin to a rudder, these three traits all serve the flatfish in its benthic lifestyle. Lastly, the generalized coloration of flatfish include a very pale underside with a cryptically pigmented dorsal side. This pigmentation serves as a camouflage for the fish and allows them to increase their survivorship via heightened predator avoidance and improved hunting behaviors. [9]

Scophthalmidae traits

The three primary synapomorphies within the Scophthalmidae family (mentioned previously under Taxonomic History) have been crucial in defining the clade. Proposed in Interrelationships of Scophthalmid Fishes, the three aforementioned synapomorphies along with two other niche traits help differentiate scophthalmids from the other flatfish. These five anatomical traits are as follows:

(i) "The anterior extension of the two pelvic fins to the isthmus" [2]

(ii) "Slightly asymmetric lateral expansions on both pelvic bones" [2]

(iii) "An elongated anterior supraoccipital process (often crenulated) in contact with the dorsal margin of the right (blind-side) frontal" [2]

(iv) "The presence of asymmetrical transverse apophyses on the caudal vertebrae" [2]

(v) "The first neural spine bent at contact with the dorsal margin of the cranium" [2]

Other non-defining traits of scophthalmids that are not specific to the family are their large and prominent lower jaws, sinistral eyes, and the single oil globule present in the yolks of their eggs. [4]

Behavior

Locomotion

Flatfish (Pleuronectiforme) in locomotion. Flatfish (PSF).png
Flatfish (Pleuronectiforme) in locomotion.

Scophthalmids live a fairly sedentary lifestyle in comparison to other ray-finned fish, and due to their negative buoyancy spend most of their time below other taxa. Being asymmetrical and spending most of their time on the bottom substrates, scophthalmids have evolved unique locomotive systems to better fit their lifestyle. Turning their bodies into levers, the flatfish use forward and backward movements to propel themselves across the substrate. Oftentimes, these movements are short, with pauses in between strokes (akin to gliding). That being said, the fish can increase their movement speed through "rapid propulsive strokes" that can propel individuals in different directions. [6]

In addition to the "rapid propulsive strokes," scophthalmids can elevate their heads into an alert position. Using both of these adaptations in tandem, the fishes can change the angle of their projection, and shoot themselves into the water column by lifting their heads and then executing a 'rapid propulsive stroke.' This is highly useful to escape predation, initiate gliding, or journey far distances while conserving energy (e.g. traveling between feeding and spawning sites). While the propulsive stroke may be energetically costly, once in the water column the flatfish can exhibit 'swim and glide' behaviors to cruise through the water. [6]

Besides the lever-system that can propel the fish in the transverse plane, scophthalmids also have unique systems to control their vertical and horizontal movements. Due to their asymmetry, their bodies are on a 90 degree rotation and use their fins differently than most Actinopterygii. Flatfish can change their vertical direction by changing the angle of their bodies, with particular emphasis on the angle of their caudal fins. [6] On the contrary, horizontal direction is controlled usnig the pectoral fin (akin to a rudder of a boat). [6]

Burying behavior

Burying is crucial to the survivorship of Scophthalmidae as it is their primary defense in avoiding predators and hunting prey. By burying, the fishes avoid detection from predation risks, and also reduce environmental challenges like current shear. [9] To initiate this important and unique behavior, flatfish vigorously beat their heads "against the sediment, accompanied by a wave of muscular [contractions] that [travel] with decreasing amplitude down the length of the body." This odd combination of muscle contractions complete two primary tasks:

(i) First, the head is driven into the substrate in the first half of the movement.

(ii) Second, the head movements "waft sediment from beneath the body so that it falls back onto the surface of the fish." [6] In this latter have of the movement the fishes do not simply swim into the substrate, they actively displace the substrate so that it falls back on top of them and conceals them.

A Flatfish (Peces Planos) using cryptic camouflage. Monterey Bay Aquarium, Monterey, CA. Flatfish.jpg
A Flatfish (Peces Planos) using cryptic camouflage. Monterey Bay Aquarium, Monterey, CA.

Location is crucial to these behaviors as some substrates are impenetrable to flatfish. This facet actively selects for specific substrates that the fish can bury in (e.g. sand), and dictate their home ranges. In The Behaviour of Flatfish, it is noted that this preference of substrate drifts towards sandy over coarse, as well as an avoidance of overly muddy substrates. The Behaviour of Flatfish does not explain as to why this is, but it could be speculated that the murkiness caused by burying in muddy substrates can be rather visible to predators, counteracting the primary function of this behavior. Time of day can also be important, as visibility decreases with access to light. Due to this factor, it is expected that burial behaviors are less common in scophthalmids at lower depths and during the night. [6]

Lastly, burying behavior does not just limit predation detection via visual cues. Indeed, burial can reduce "conspicuousness," [6] but flatfish can employ additional tools to solidify their defense. Scophthalmids are believed to be capable of lowering heart rates and well as decreasing oxygen consumption, in turn sending less involuntary cues of their presence and reduce the chemical signals sent to predators. [6]

Feeding behavior

Feeding is crucial to any organisms behavior as it is necessary to sustain life. Unlike other organisms, however, temperature plays a significant role in determining feeding intensity and growth. [6] [10] While making Scophthalmidae more susceptible to climate change, this force also helps dictate population size and drives growth to be proportional to the various seasons. [11] Being that Scophthalmidae is a family of flatfish very similar to other Pleuronectiformes, dietvaries. Flatfish take advantage of complex environments while most fish have no choice but to hunt in open water. This gives the fishes relatively high plasticity in their feeding behaviors and they enlist a wide range of tactics. Visits to species pages will give higher insight onto the specific feeding-type of said species. By the same merit, below are the general feeding-types and elements of feeding behavior that exist within the order:

The three general feeding types [6]

  1. "Visual feeders that consume free-swimming prey"
  2. "Visual feeders that take principally slow-moving and sedentary benthic prey"
  3. "Non-visual nocturnal feeders that consume sedentary benthic prey"

All three feeding types involve the various elements of feeding behavior. Visual predation is the most common in flatfish, but the non-visual nocturnal species rely on chemical cues left in the water (e.g. distress signals, high heart rates, oxygen consumption, cortisol levels, olfactory chemicals, decomposition, etc.).

The four elements of feeding behavior [6]

  1. Searching: Searching tends to be initiated via hunger, but can also be induced via chemical signals in the water. Generally a slow process, they tend to swim upstream to track olfactory clues and primarily rely on vision during the hunt (they have extensive vision in all planes due to their protrusive eyes and cranial anatomy). [6]
  2. Encountering: The senses are used to take in both visual and chemical cues (which are important for marine species). Both of these factors have been proved to increase the attractiveness of prey items. [12] In addition to those factors, flatfish have keen motion detection via "wide-set eyes" and a "lateral line system" on their head or body that can be stimulated by motion. [6]
  3. Capture: Capture consists of three sub-elements that can dictate the style of capture or 'type of hunt.'
    1. Pursuit: Pursuit is common in faster taxon as the individual uses sheer speed to run down free-swimming prey. [6]
    2. Stalking: Stalking is a method different from ambushing. Taxon that use this style of capture lure outside of detection of the prey item, and their primary weapon is stealth and striking. [6]
    3. Ambush: Ambush species use their unique adaptations and combine stillness, burying, or cryptic coloration until prey is in striking distance. [6]
  4. Ingestion: After capture, all that is left is ingestion, digestion, and defecation.

Reproduction

Similar stacking positioning in courtship behavior of Green Sea Turtles (Chelonia mydas) Courtship of green turtles.jpg
Similar stacking positioning in courtship behavior of Green Sea Turtles (Chelonia mydas)

Courtship

Little is known in regards to the reproduction of scophthalmids beyond what is widely accepted or generalized in the broader flatfish order. When a female enters a reproductive state (due to internal or external stimuli), courtship is usually initiated by the male. Male Pleuronectiformes follow the female individual across the sea floor, and then maneuvers either above or below the female depending on the species. If successfully courted, the female (now with the male) rise through the water column. The pair reaches the climax of the courtship ritual as they reach the "apex of the rise," where gametes are released into the water. [6] Following this dispersal of gametes, the two return to the seafloor having successfully mated.

Life stages

Akin to courtship behaviors, scophthalmids also share a three-stage spawning behavior just like other flatfish. [6] Spawning tends to take place in the evening, and males and females generally pair due to relative body size. [6] One interesting fact about flatfish is that most species are actually born symmetrical, and their eyes rotate as they mature (can travel 10-25mm on average). As the fish develop, the non-dominant eye 'floats' to the dominant side over time, resulting in the intrinsic asymmetry of the order. [4]

Female can indicate their "readiness to spawn by rapidly raising and lowering their heads." [6] This in turn inclines males to approach and produce a threat signal, circling the female "flagging with the pectoral fin." [6] Speculation as to why is not solidified in scientific literature but it is possibly due to competition in paternity.

Conservation status and threats

Visual representation of the Change in Temperature in the North Atlantic from 1850 to 2000. Each stripe represents the temperature averaged over a year. Temperature Bar Chart Ocean-North Atlantic--1850-2020--2021-07-13.png
Visual representation of the Change in Temperature in the North Atlantic from 1850 to 2000. Each stripe represents the temperature averaged over a year.

Climate change

The Latitudinal Gradient is a common term in describing the change of a certain variable with respect to global latitudes. Due to the tilt of the Earth as well as the distance from the sun, this latitudinal gradient is often proportional to the global temperature gradient, both on water and land. [13] The temperature gradient of the ocean is crucial for all marine life as some species are specialized for different regions or use temperature to direct migrations. Thus, species that reside in temperate latitudes tend to have broader preferences and tolerances then species specialized for extreme temperatures. This makes both tropical and polar species more susceptible to  changes in climate. [14] Flatfish are negatively affected by these temperature shifts and continue to decline in populations. Globally, their numbers dwindle and have been since the 1970s. [14] The use of technology has allowed researchers to calculate numbers of existing populations as well as estimate the future of the clade. Two of these methods, a vulnerability assessment and simulation model projections, help pinpoint the regions at highest risk of this change and align with previously mentioned latitudinal gradient predictions. [14] Findings suggest that the Indo-Pacific and Northeast Atlantic are at the highest risk of impacts due to climate change [14] (i.e. a tropical region and polar region). As mentioned previously, scophthalmids are almost exclusively located in the Northeast Atlantic and will suffer heavily from this. [3] [4] [13] [14] Interestingly enough, the rapid warming was exacerbated regionally due to factors such as human populations, freshwater prevalence, and land-locking. [11] The highest levels of warming (“LMEs warming at rates 2–4 times the global mean rate” [11] )  was confined to certain areas, especially in the North Atlantic. Regions that Scophthalmidae are native to (i.e. the Baltic, Mediterranean, and Black seas) all fall under this hotspot. It seems that this regional increase of warming can be traced to the “natural variability related to the North Atlantic Oscillation” as well as adjacent terrestrial warming near the coastal seas (caused by industrial/anthropogenic advancements). [11]

In addition to this fact, the increasingly negative population dynamics of all flatfish indicates that the clade has reached its maximum potential. [14] Furthermore, some fisheries have overfished certain regions to the point of collapse. [15] In these regions a bounce-back in population is not expected. This change is not just due to temperature change, but additional factors tied to climate change (i.e. ocean acidification, oxygen depletion, and decreases in net primary production). Climate change is a multivariate problem for scophthalmids as it has led to changes in distribution and net productivity in addition to the aforementioned decreases in population. [14] Yet, these changes in distribution are not exclusive to potentially obvious latitudinal range shifts. The flatfish have also been observed migrating within regions, shifting their depth as well. [16] Averaging to only several meters per decade, [16] this seemingly small change is drastic for the family. While decreasing depth can help scophthalmids fight the change in ocean temperature, the deeper they travel the less light can penetrate and both conditions and productivity also decrease. [14] This is a negative constraint on the fish which will eventually reach its limit.

Lastly, scophthalmids are simply less mobile than other taxa. [14] Their activity rate is much lower than other fish of similar size and location (alternate pelagic and demersal species). Because of this, it is harder to migrate, maneuver, and adapt, making their adjustment period relatively slow. [14] All finfish (including scophthalmids), however, are expected to shrink. [17] [18] [19] The decrease in body size relates to the temperature change via oxygen levels. The growing restriction on oxygen levels proportional to the increase in temperature negatively affects body size, adding yet another side effect to the changing climate. [19]

Trawl Fishing Depiction Trawling Drawing new.png
Trawl Fishing Depiction

Trawl fishing

Put plainly, trawl fishing is when nets are dragged through the water to catch as many fish as possible. Bottom trawling (primarily industrially committed) is when this method is used on the seafloor where the nets are weighted and dragged. [20] Frowned upon by marine biologists, bottom trawling is harmful to the ecosystem due to the displacement of sediment and organisms as well as the irreversible damage it creates. [20] In addition to negatively affecting the ecosystem, bottom trawling proves to be highly dangerous to scophthalmids as well as other families of flatfish. This method of fishing exploits scophthalmids’ natural predator avoidance behaviors. [7] Flatfish find comfort with the substrate, and use detection minimization techniques as their primary avoidance behavior. [7] These strategies combine various techniques such as “ burial, highly evolved cryptic capabilities, and low activity,” [7] all of which are useless and therefore detrimental in fighting trawls.

The first indication of a trawling vessel is the sound vibrations sent through the water. [7] This stimulus is received by the fish ("which have good hearing in the range of 300–1000 Hz" [21] ) and the scophthalmids then respond by diving. [22] Because of this, while flatfish do not school or directly herd as an avoidance behavior, individuals indirectly herd in the regard by which they are all migrating in the same direction. This increase in concentration is dangerous as it increases catch per trawl, oftentimes when the flatfish are not even the desired target (bycatch). [7]

Highly specialized behaviors are hard to change, making the flatfishes' natural instinct to minimize detection rendered useless. Usually they can be rather cryptic, and have great success avoiding natural predators.  Utilizing their low body profile and texture-matching colorations, they become hard to detect. [9] [23] Furthering their camouflage, they have behavioral modifications that work in tandem to their anatomy. Scophthalmidae share a strong inclination to bury themselves and to cease movement, fighting the desire to flee until extremely close to detection. [24] [25] [26] In addition to being inclined to hiding, in the instance they are being caught, flatfish face the disadvantage of their maximum swim speed. Only able to sustain a certain speed at relatively lower rates than most roundfish, flatfish tend to respond to the trawls in short bursts and generally remain unresponsive until "approx. <1 meter away." [7] After observing the adaptations Scophthalmidae have made to survive in the Ocean, bottom trawling proves to be a major industrial threat to scophthalmids because of its own nature in specifically targeting and taking advantage of flatfish behavior. [10]

Related Research Articles

<span class="mw-page-title-main">Flatfish</span> Order of fishes

A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through or around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward.

<span class="mw-page-title-main">Teleost</span> Infraclass of fishes

Teleostei, members of which are known as teleosts, is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, and contains 96% of all extant species of fish. Teleosts are arranged into about 40 orders and 448 families. Over 26,000 species have been described. Teleosts range from giant oarfish measuring 7.6 m (25 ft) or more, and ocean sunfish weighing over 2 t, to the minute male anglerfish Photocorynus spiniceps, just 6.2 mm (0.24 in) long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses.

<span class="mw-page-title-main">Turbot</span> Species of flatfish in the family Scophthalmidae

The turbot is a relatively large species of flatfish in the family Scophthalmidae. It is a demersal fish native to marine or brackish waters of the Northeast Atlantic, Baltic Sea and the Mediterranean Sea. It is an important food fish. Turbot in the Black Sea have often been included in this species, but are now generally regarded as separate, the Black Sea turbot or kalkan. True turbot are not found in the Northwest Atlantic; the "turbot" of that region, which was involved in the so-called "Turbot War" between Canada and Spain, is the Greenland halibut or Greenland turbot.

<span class="mw-page-title-main">European plaice</span> Species of fish

The European plaice, commonly referred to as simply plaice, is a species of marine flatfish in the genus Pleuronectes of the family Pleuronectidae.

<span class="mw-page-title-main">Hogchoker</span> Species of flatfish

The hogchoker is a small species of flatfish found along the Atlantic and Gulf coasts of North and South America, ranging from Massachusetts to Venezuela. They prefer brackish water, and are abundant in many bays and estuaries north of the Carolinas. It is a member of the American sole family Achiridae. They are usually brown to dark brown in color, and lighter on their "blind side". The overall body color is often broken by a series of spots and thin stripes, which can be lighter or darker than the main body color. The fins and tail have fringed edges helping hide the fish from its prey. They mainly feed on small aquatic insects and invertebrates. They are regarded as "trash fish" by recreational fishermen and were fed to pigs but they have rather bony bodies which were sometimes difficult for the pigs to swallow, hence the vernacular name.

<span class="mw-page-title-main">Demersal fish</span> Fish that live and feed on or near the bottom of seas or lakes

Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes. They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks. In coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. They are not generally found in the deepest waters, such as abyssal depths or on the abyssal plain, but they can be found around seamounts and islands. The word demersal comes from the Latin demergere, which means to sink.

<span class="mw-page-title-main">Brill (fish)</span> Species of fish

The brill is a species of flatfish in the turbot family (Scophthalmidae) of the order Pleuronectiformes. Brill can be found in the northeast Atlantic, Black Sea, Baltic Sea, and Mediterranean, primarily in deeper offshore waters.

<span class="mw-page-title-main">Starry flounder</span> Species of fish

The starry flounder, also known as the grindstone, emery wheel and long-nosed flounder, is a common flatfish found around the margins of the North Pacific.

<span class="mw-page-title-main">Yellowbelly flounder</span> Species of fish

The yellowbelly flounder is a flatfish of the genus Rhombosolea, found around New Zealand. A different species from the genus Rhombosolea is found in Australia and also goes by the name yellow-belly flounder. The Māori people have commonly fished for R. leporina, and many other species of flatfish, throughout New Zealand's coastal waters for hundreds of years. The Māori name for this species is pātiki tōtara.

<span class="mw-page-title-main">New Zealand turbot</span> Species of fish

The New Zealand turbot, Colistium nudipinnis, is a righteye flounder of the subfamily Rhombosoleinae in the family Pleuronectidae, found around New Zealand in shallow enclosed waters.

<span class="mw-page-title-main">Humpback smooth-hound</span> Species of shark

The humpback smooth-hound is a species of houndshark and a part of the family Triakidae.The most noticeable difference between Mustelus whitneyi and its relatives, is the slight curvature, causing a "humpback" appearance located in front of its primary dorsal fin. It is found on the continental shelves of the tropical southeast Pacific, from Peru to southern Chile, between latitudes 3° S and 54° S. These sharks are demersal feeders but range from depths between 15 and 210 metres. Humpback smooth-hound sharks are small sharks, reaching a maximum size of 118cm in total length. Mustelus whitneyi typically feed on teleosts and invertebrates in the benthic and pelagic ecosystems, most important prey being the peruvian anchovy. These humpback smooth-hound sharks are placental viviparious sharks, meaning that the embryo forms inside the mother tethered by the placental cord. The threats currently causing population decline to humpback smooth-hound sharks surround issues with local fisheries and management.

<span class="mw-page-title-main">Witch (righteye flounder)</span> Species of fish

The witch, known in English by a variety of other common names including the witch flounder, pole flounder, craig fluke, Torbay sole, and grey sole, is a species of flatfish from the family Pleuronectidae. It occurs on both sides of the North Atlantic Ocean on muddy sea beds in quite deep water. In northern Europe it has some importance in fisheries as a food fish.

<span class="mw-page-title-main">Greenland halibut</span> Species of fish

The Greenland halibut or Greenland turbot belongs to the family Pleuronectidae, and is the only species of the genus Reinhardtius. It is a predatory fish that mostly ranges at depths between 500 and 1,000 m (1,600–3,300 ft), and is found in the cold northern Atlantic, northern Pacific, and Arctic Oceans.

<span class="mw-page-title-main">European flounder</span> Species of fish

The European flounder is a flatfish of European coastal waters from the White Sea in the north to the Mediterranean and the Black Sea in the south. It has been introduced into the United States and Canada accidentally through transport in ballast water. It is caught and used for human consumption.

<i>Achirus lineatus</i> Species of fish

The lined sole is a ray-finned flatfish found in the Western Atlantic. Its common length is 17 cm. Often considered a trash fish in commercial trawling, it is of little or no economic value.

<span class="mw-page-title-main">Samaridae</span> Family of fishes

Samaridae is a family of crested flounders, small flatfishes native to the Indo-Pacific. The family contains four genera with a total of 29 species.

<i>Symphurus thermophilus</i> Species of fish

Symphurus thermophilus is a species of tonguefish notable for being the only flatfish known to be an obligate inhabitant of hydrothermal vents. It is known from several widely dispersed locations in the western Pacific Ocean and occurs in great numbers. They are tolerant of harsh conditions and are often found in close association with elemental sulfur, including molten sulfur pools that exceed 180 °C in temperature. As they are not significantly different in appearance and feeding habits from other tonguefishes, they are thought to be relatively recent colonizers of vent ecosystems.

<span class="mw-page-title-main">Mediterranean scaldfish</span> Species of fish

The Mediterranean scaldfish, also known as the scaldfish, is a species of benthic left eyed flatfish belonging to the family Bothidae. It is found in the eastern Atlantic of Europe and Africa as well as the Mediterranean, and is of minor interest to fisheries.

<i>Zebrias</i> Genus of fishes

Zebrias is a genus of ray-finned fish in the family Soleidae.

<span class="mw-page-title-main">Egyptian sole</span> Species of fish

The Egyptian sole is a species of flatfish in the true sole family, Soleidae. It lives on the sandy or muddy seabed of the Mediterranean Sea, and is now colonising the Red Sea. It often semi-immerses itself in the substrate. The upper side is greyish-brown while the underside is white. It grows to a maximum length of about 70 cm (28 in). This fish is used for human consumption and is prized as a food fish. It is caught mostly by trawling on the seabed.

References

  1. 1 2 Froese, Rainer, and Daniel Pauly, eds. (2012). "Scophthalmidae" in FishBase. December 2012 version.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Chanet, B. (2003). Interrelationships of scophthalmid fishes (Pleuronectiformes: Scopththalmidae). Cybium 27(4) 275-86.
  3. 1 2 3 4 eol - Encyclopedia of Life taxon Scophthalmidae at http://www.eol.org.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 Nelson, Joseph S. (2006). Fishes of the World, 4th Ed. ISBN   0-471-25031-7
  5. 1 2 Froese, R. and D. Pauly. Editors. 2022. FishBase. World Wide Web Electronic Publication. www.fishbase.org, Version (02/2022). FishBase (Family Scophthalmidae - Turbots)
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  8. ↑ Kardong, Kenneth V. (2015). Vertebrates: Comparative Anatomy, Function, Evolution (7th ed.). New York. ISBN   978-0-07-802302-6. OCLC   862149184.{{cite book}}: CS1 maint: location missing publisher (link)
  9. 1 2 3 Ramachandran, V. S.; Tyler, C. W.; Gregory, R. L.; Rogers-Ramachandran, D.; Duensing, S.; Pillsbury, C.; Ramachandran, C. (1996). "Rapid Adaptive Camouflage in Tropical Flounders". Nature. 379 (6568): 815–818. Bibcode:1996Natur.379..815R. doi:10.1038/379815a0. ISSN   0028-0836. PMID   8587602. S2CID   4304531.
  10. 1 2 Stoner, Allan W.; Ottmar, Michele L.; Hurst, Thomas P. (2006). "Temperature affects activity and feeding motivation in Pacific halibut: Implications for bait-dependent fishing". Fisheries Research. 81 (2–3): 202–209. doi:10.1016/j.fishres.2006.07.005. ISSN   0165-7836.
  11. 1 2 3 4 Belkin, Igor M. (2009-04-01). "Rapid warming of Large Marine Ecosystems". Progress in Oceanography. Comparative Marine Ecosystem Structure and Function: Descriptors and Characteristics. 81 (1): 207–213. Bibcode:2009PrOce..81..207B. doi:10.1016/j.pocean.2009.04.011. ISSN   0079-6611.
  12. ↑ de Groot, S. J. (1969). "Digestive System and Sensorial Factors in Relation to the Feeding Behaviour of Flatfish (Pleuronectiformes)". ICES Journal of Marine Science. 32 (3): 385–394. doi:10.1093/icesjms/32.3.385. ISSN   1054-3139.
  13. 1 2 Tittensor, Derek P.; Mora, Camilo; Jetz, Walter; Lotze, Heike K.; Ricard, Daniel; Berghe, Edward Vanden; Worm, Boris (2010). "Global Patterns and Predictors of Marine Biodiversity Across Taxa". Nature. 466 (7310): 1098–1101. Bibcode:2010Natur.466.1098T. doi:10.1038/nature09329. ISSN   1476-4687. PMID   20668450. S2CID   4424240.
  14. 1 2 3 4 5 6 7 8 9 10 Cheung, William W.L.; Oyinlola, Muhammed A. (October 2018). "Vulnerability of Flatfish and their Fisheries to Climate Change". Journal of Sea Research. 140: 1–10. Bibcode:2018JSR...140....1C. doi:10.1016/j.seares.2018.06.006. S2CID   90399407 – via ScienceDirect.
  15. ↑ Rice, Jake; Cooper, J. Andrew (2003). "Management of flatfish fisheries—what factors matter?". Journal of Sea Research. 50 (2–3): 229–245. Bibcode:2003JSR....50..229R. doi:10.1016/j.seares.2003.07.001.
  16. 1 2 Cheung, William W. L.; Dunne, John; Sarmiento, Jorge L.; Pauly, Daniel (2011). "Integrating Ecophysiology and Plankton Dynamics into Projected Maximum Fisheries Catch Potential Under Climate Change in the Northeast Atlantic". ICES Journal of Marine Science. 68 (6): 1008–1018. doi: 10.1093/icesjms/fsr012 . ISSN   1095-9289.
  17. ↑ Cheung, W.W.L; Sarmiento, J.L.; Dunne, J.; Frölicher, T.L.; Lam, V.W.Y.; Palomares, M.L.D.; Watson, R.; Pauly, D. (2013). "Shrinking of Fishes Exacerbates Impacts of Global Ocean Changes on Marine Ecosystems". Nature Climate Change. 3 (3): 254–258. Bibcode:2013NatCC...3..254C. doi:10.1038/nclimate1691 – via Nature.
  18. ↑ Tittensor, D.P.; Mora, C.; Jetz, W.; Lotze, H.K.; Ricard, D.; Berghe, E.V.; Worm, B. (2010). "Global Patterns and Predictors of Marine Biodiversity Across Taxa". Nature. 466 (7310): 1098–1101. Bibcode:2010Natur.466.1098T. doi:10.1038/nature09329. PMID   20668450. S2CID   4424240.
  19. 1 2 Pauly, D.; Cheung, W.W.L. (2018). "Sound Physiological Knowledge and Principles in Modeling Shrinking of Fishes Under Climate Change". Global Change Biology. 24 (1): 15–26. Bibcode:2018GCBio..24E..15P. doi: 10.1111/gcb.13831 . PMID   28833977. S2CID   3364627 – via ResearchGate.
  20. 1 2 "Bottom trawling releases as much carbon as air travel, landmark study finds". the Guardian. 2021-03-17. Retrieved 2022-04-24.
  21. ↑ Popper, Arthur N. (2003). "Effects of Anthropogenic Sounds on Fishes". Fisheries. 28 (10): 24–31. doi:10.1577/1548-8446(2003)28[24:eoasof]2.0.co;2. ISSN   0363-2415.
  22. ↑ Handegard, N. O.; Tjøstheim, D. (2005). "When fish meet a trawling vessel: examining the behaviour of gadoids using a free-floating buoy and acoustic split-beam tracking". Canadian Journal of Fisheries and Aquatic Sciences. 62 (10): 2409–2422. doi:10.1139/f05-131. hdl: 11250/108691 . ISSN   0706-652X.
  23. ↑ Healey, E. G. (1999). "The skin pattern of young plaice and its rapid modification in response to graded changes in background tint and pattern". Journal of Fish Biology. 55 (5): 937–971. doi:10.1111/j.1095-8649.1999.tb00732.x. ISSN   0022-1112.
  24. ↑ BURROWS, MICHAEL T.; GIBSON, ROBIN N. (1995). "The effects of food, predation risk and endogenous rhythmicity on the behaviour of juvenile plaice,Pleuronectes platessaL". Animal Behaviour. 50 (1): 41–52. doi:10.1006/anbe.1995.0219. ISSN   0003-3472. S2CID   53204876.
  25. ↑ Lemke, Jena L.; Ryer, Clifford H. (2006). "Risk sensitivity in three juvenile (Age-0) flatfish species: Does estuarine dependence promote risk-prone behavior?". Journal of Experimental Marine Biology and Ecology. 333 (2): 172–180. doi:10.1016/j.jembe.2005.12.004. ISSN   0022-0981.
  26. ↑ Lemke, JL; Ryer, CH (2006-12-20). "Relative predation vulnerability of three juvenile (Age-0) North Pacific flatfish species: possible influence of nursery-specific predation pressures". Marine Ecology Progress Series. 328: 267–273. Bibcode:2006MEPS..328..267L. doi: 10.3354/meps328267 . ISSN   0171-8630.
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