Zeidae
Encyclopedia
The Zeidae are a family
of large, showy, deep-bodied zeiform marine fish
—the "true dories
". Found in the Atlantic
, Indian
, and Pacific Ocean
, the family contains just six species
in two genera
. All species are important and highly-regarded food fish supporting commercial fisheries
, and some—such as the John dory
(Zeus faber)—are enjoyed in large public aquaria
. These fish are caught primarily via deep-sea trawling.
There are several other families with members sharing the common name
dory, some of which—i.e., those of genera Capromimus, Cyttomimus, and Cyttus
—were once treated within the Zeidae. The first two genera are now found within the Zenionidae
(or Zeniontidae), and the last genus has been given its own family, Cyttidae.
species, it is noticeably upturned. The jaw
s are massive and highly extensile. The large eyes are situated high on the head and are directed dorsolaterally. There is a perceptible hump in the back beginning just behind the eye; it is topped by a conspicuous, crest-shaped spinous
dorsal fin
containing 7–10 spines which descend in height towards the posterior. In adults of some species, the dorsal spines are adorned with long, streamer-like filaments. A second, much lower dorsal fin (with 22–37 soft rays) extends down the rest of the back, in a slight retrorse direction due to the body's curvature. The caudal peduncle is thin and the caudal fin is small and truncate (brush-shaped).
The pelvic fins are thoracic, spineless, and greatly elongated; the rays are free of their membranes distally. The pectoral fins are small, short, and rounded, inserted fairly low on the body and posterior to the pelvics. The anal fin contains 1–4 spines anteriorly and 20–39 soft rays with their height, direction, origin, and terminus mirroring those of the soft dorsal fin. Along the belly are a series of spinous scute
s—scale
s modified into hard, bony plates—forming an armoured ventral keel. Similar scutes also cover the base of the dorsal and anal fins. The opercular bones
are free of any spines or serrations. The vertebrae number 29–34, and adults possess degenerate gill raker
s.
The body is apparently naked; if present, the scales are microscopic. Coloration in life is typically a highly lustrous silver, with younger dories covered in a number of randomly-placed dark, dusky spots. These spots tend to fade with age; the largest (and oldest) specimens have only one dark spot, located roughly central on the flanks. In the cape dory (Zeus capensis) this spot is located just below the junction of the spinuos and soft dorsal fins; in the John dory the spot is central and surrounded by a yellow ring, with the body also covered in cloud-like splotches of muddy sepia. Zeus capensis and Z. faber are tied as the largest dory species at a maximum 90 centimetres total length, with the other three species only slightly smaller.
fish, dories are typically found close to or directly over the sea bottom, but occasionally in midwater as well. Depths frequented are moderate, ca. 50–800 metres; muddy substrates are preferred, usually over the continental shelf
and slope, near the coast. Some, such as the silvery John dory (Zenopsis conchifera), form small and loose schools; while others, such as the John dory, are generally solitary when not spawning
. Dories are poor swimmers; they propel themselves primarily via a balistiform (i.e., like the triggerfish
s) mode of locomotion, with the dorsal and anal fins undulating in unison as the main propulsive force and the pectoral fins used for stabilisation and turning.
The reproduction of the Zeidae are not well studied as a whole; all are assumed to be non-guarding, substrate scatterers; that is, a large number of tiny eggs
and sperm
are released en masse and scattered over a wide area. The fertilized eggs are negatively buoyant and sink into the substrate, to which they adhere. Spawning activity appears to peak in the summer months in the John dory, and in the winter months in the mirror dory
(Zenopsis nebulosa). In the latter species fertilization is reported to be internal (within the oviduct
), whereas in the former species it is external. Growth is rapid and sexual maturity
is reached by 3–4 years.
The Zeidae are top predators in their habitat
and are noted for their marked stenophagy: juveniles feed exclusively on zooplankton
, such as copepod
s, euphausiids, mysids, apheids, pandalids, palaemonids, and other small crustacean
s. Conversely, adults feed almost exclusively on active schooling fish, such as pearlsides
, porgie
s, young carangid
s (e.g., mackerel
s), and clupeid
s (e.g., sardine
s and pilchards); and other benthic fish, such as dragonet
s, gobies
, filefish
, flatfish
, bandfish
, and sea chub
s; and occasionally on cephalopod
s such as squid
and cuttlefish
.
Predators of dories include large shark
s such as the dusky shark
(Carcharhinus obscurus) and other requiem shark
s, and larger shelf- and slope-dwelling bony fish, such as predatory Moehau
, and merluccid hakes.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of large, showy, deep-bodied zeiform marine fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
—the "true dories
Dory (fish)
The common name dory is shared by members of several different families of large-eyed, silvery, deep-bodied, laterally compressed, and roughly discoid marine fish. As well as resembling each other, dories are also similar in habit: most are deep-sea and demersal...
". Found in the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, Indian
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
, and Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, the family contains just six species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in two genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. All species are important and highly-regarded food fish supporting commercial fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
, and some—such as the John dory
John Dory
John Dory, also known as St Pierre or Peter's Fish, refers to fish of the genus Zeus, especially Zeus faber, of widespread distribution. It is an edible benthic coastal marine fish with a laterally compressed olive-yellow body which has a large dark spot, and long spines on the dorsal fin...
(Zeus faber)—are enjoyed in large public aquaria
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
. These fish are caught primarily via deep-sea trawling.
There are several other families with members sharing the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
dory, some of which—i.e., those of genera Capromimus, Cyttomimus, and Cyttus
Cyttus
Cyttidae is a family of large, showy, deep-bodied zeiform marine fish. Found in the Atlantic, Indian, and Pacific Ocean, the family contains just three species in the single genus Cyttus.- Species :...
—were once treated within the Zeidae. The first two genera are now found within the Zenionidae
Zenionidae
The Zenionidae are a family of large, showy, deep-bodied zeiform marine fish. Found in the Atlantic, Indian, and Pacific Ocean, the family contains just seven species in three genera.The family was formerly known as Macrurocyttidae.- Species :...
(or Zeniontidae), and the last genus has been given its own family, Cyttidae.
Physical description
All dories share the same roughly discoid, laterally-compressed body plan. The head is large and sloping to concave in profile; the oblique mouth is also large and in ZenopsisZenopsis
Zenopsis is a genus of dory with a fossil record dating back to the Oligocene epoch....
species, it is noticeably upturned. The jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...
s are massive and highly extensile. The large eyes are situated high on the head and are directed dorsolaterally. There is a perceptible hump in the back beginning just behind the eye; it is topped by a conspicuous, crest-shaped spinous
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
containing 7–10 spines which descend in height towards the posterior. In adults of some species, the dorsal spines are adorned with long, streamer-like filaments. A second, much lower dorsal fin (with 22–37 soft rays) extends down the rest of the back, in a slight retrorse direction due to the body's curvature. The caudal peduncle is thin and the caudal fin is small and truncate (brush-shaped).
The pelvic fins are thoracic, spineless, and greatly elongated; the rays are free of their membranes distally. The pectoral fins are small, short, and rounded, inserted fairly low on the body and posterior to the pelvics. The anal fin contains 1–4 spines anteriorly and 20–39 soft rays with their height, direction, origin, and terminus mirroring those of the soft dorsal fin. Along the belly are a series of spinous scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s—scale
Scale (zoology)
In most biological nomenclature, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, and provide coloration...
s modified into hard, bony plates—forming an armoured ventral keel. Similar scutes also cover the base of the dorsal and anal fins. The opercular bones
Operculum (fish)
The operculum of a bony fish is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body....
are free of any spines or serrations. The vertebrae number 29–34, and adults possess degenerate gill raker
Gill raker
Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch and are involved with filter feeding tiny prey. They are not to be confused with the gill filaments that compose the bony part of the gill. Rakers are usually present in two rows, projecting from both the...
s.
The body is apparently naked; if present, the scales are microscopic. Coloration in life is typically a highly lustrous silver, with younger dories covered in a number of randomly-placed dark, dusky spots. These spots tend to fade with age; the largest (and oldest) specimens have only one dark spot, located roughly central on the flanks. In the cape dory (Zeus capensis) this spot is located just below the junction of the spinuos and soft dorsal fins; in the John dory the spot is central and surrounded by a yellow ring, with the body also covered in cloud-like splotches of muddy sepia. Zeus capensis and Z. faber are tied as the largest dory species at a maximum 90 centimetres total length, with the other three species only slightly smaller.
Life history
As benthicBenthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...
fish, dories are typically found close to or directly over the sea bottom, but occasionally in midwater as well. Depths frequented are moderate, ca. 50–800 metres; muddy substrates are preferred, usually over the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
and slope, near the coast. Some, such as the silvery John dory (Zenopsis conchifera), form small and loose schools; while others, such as the John dory, are generally solitary when not spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
. Dories are poor swimmers; they propel themselves primarily via a balistiform (i.e., like the triggerfish
Triggerfish
Triggerfishes are about 40 species of often brightly colored fishes of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacific...
s) mode of locomotion, with the dorsal and anal fins undulating in unison as the main propulsive force and the pectoral fins used for stabilisation and turning.
The reproduction of the Zeidae are not well studied as a whole; all are assumed to be non-guarding, substrate scatterers; that is, a large number of tiny eggs
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
and sperm
Spermatozoon
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...
are released en masse and scattered over a wide area. The fertilized eggs are negatively buoyant and sink into the substrate, to which they adhere. Spawning activity appears to peak in the summer months in the John dory, and in the winter months in the mirror dory
Mirror dory
The mirror dory, Zenopsis nebulosa, is a dory of the family Zeidae, found in the southern Pacific Ocean at depths of between 30 and 800 m. Its length is up to 70 cm....
(Zenopsis nebulosa). In the latter species fertilization is reported to be internal (within the oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
), whereas in the former species it is external. Growth is rapid and sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
is reached by 3–4 years.
The Zeidae are top predators in their habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
and are noted for their marked stenophagy: juveniles feed exclusively on zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
, such as copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
s, euphausiids, mysids, apheids, pandalids, palaemonids, and other small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s. Conversely, adults feed almost exclusively on active schooling fish, such as pearlsides
Pearlsides
Mueller's pearlside or Mueller's bristle-mouth fish, Maurolicus muelleri, a marine hatchetfish of the genus Maurolicus, is found in deep tropical and subtropical waters of all oceans, from the surface to depths of 1,500 m...
, porgie
Porgy
Porgy is a novel written by American author DuBose Heyward in 1925, as well as a play Dorothy Heyward helped him to write which debuted in 1927....
s, young carangid
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
s (e.g., mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
s), and clupeid
Clupeidae
Clupeidae is the family of the herrings, shads, sardines, hilsa and menhadens. It includes many of the most important food fishes in the world.-Description and biology:...
s (e.g., sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
s and pilchards); and other benthic fish, such as dragonet
Dragonet
Dragonets are small, perciform, marine fish of the diverse family Callionymidae . Found mainly in the tropical waters of the western Indo-Pacific, the family contains approximately 186 species in 18 genera. The Draconettidae may be considered a sister family, whose members are very much alike,...
s, gobies
Goby
The gobies form the family Gobiidae, which is one of the largest families of fish, with more than 2,000 species in more than 200 genera. Most are relatively small, typically less than 10 cm in length...
, filefish
Filefish
Filefish are tropical to subtropical tetraodontiform marine fish of the diverse family Monacanthidae. Found in the Atlantic, Pacific and Indian Oceans, the filefish family contains approximately 107 species in 26 genera...
, flatfish
Flatfish
The flatfish are an order of ray-finned fish, 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 and around the head during development...
, bandfish
Bandfish
Bandfishes are a family, Cepolidae, of perciform fishes. They are native to the Atlantic seaboard of Europe and the West Pacific, including New Zealand. They dig burrows in sandy or muddy seabed and eat zooplankton....
, and sea chub
Sea chub
The sea chubs are a family, Kyphosidae, of fishes in the order Perciformes.-Subfamilies:* Girellinae - nibblers* Kyphosinae* Microcanthinae Johnson, 1984 * Scorpidinae...
s; and occasionally on cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s such as squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
and cuttlefish
Cuttlefish
Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....
.
Predators of dories include large shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s such as the dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(Carcharhinus obscurus) and other requiem shark
Requiem shark
Requiem sharks are a family, Carcharhinidae, of sharks in the order Carcharhiniformes, containing migratory, live-bearing sharks of warm seas such as the tiger shark, the blue shark, the bull shark, and the milk shark.The name may be related to the French word for shark, "requin", itself of...
s, and larger shelf- and slope-dwelling bony fish, such as predatory Moehau
Moehau
The Moehau is reputed to be a large, hairy hominid in the Coromandel-Moehau ranges of New Zealand's North Island. These stories of sightings of "The Hairy Moehau" or "The Moehau Monster" have given rise to various explanations....
, and merluccid hakes.
Species
There are six species in two genera:- Genus ZenopsisZenopsisZenopsis is a genus of dory with a fossil record dating back to the Oligocene epoch....
- Silvery John dory, Zenopsis conchifera (Lowe, 1852).
- Mirror doryMirror doryThe mirror dory, Zenopsis nebulosa, is a dory of the family Zeidae, found in the southern Pacific Ocean at depths of between 30 and 800 m. Its length is up to 70 cm....
, Zenopsis nebulosa (TemminckCoenraad Jacob TemminckCoenraad Jacob Temminck was a Dutch aristocrat and zoologist.Temminck was the first director of the National Natural History Museum at Leiden from 1820 until his death. His Manuel d'ornithologie, ou Tableau systematique des oiseaux qui se trouvent en Europe was the standard work on European birds...
& SchlegelHermann SchlegelHermann Schlegel was a German ornithologist and herpetologist.-Early life and education:Schlegel was born at Altenburg, the son of a brassfounder. His father collected butterflies, which stimulated Schlegel's interest in natural history...
, 1845). - Zenopsis oblongus Parin, 1989.
- Zenopsis stabilispinosa Nakabo et al., 2006.
- Genus Zeus
- Cape dory, Zeus capensis ValenciennesAchille ValenciennesAchille Valenciennes was a French zoologist.Valenciennes was born in Paris, and studied under Georges Cuvier. Valenciennes' study of parasitic worms in humans made an important contribution to the study of parasitology...
, 1835. - John doryJohn DoryJohn Dory, also known as St Pierre or Peter's Fish, refers to fish of the genus Zeus, especially Zeus faber, of widespread distribution. It is an edible benthic coastal marine fish with a laterally compressed olive-yellow body which has a large dark spot, and long spines on the dorsal fin...
, Zeus faber LinnaeusCarolus LinnaeusCarl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
, 1758
- Cape dory, Zeus capensis Valenciennes