Lookdown
Encyclopedia
The lookdown, Selene vomer, is a game fish of the Carangidae
family
. The lookdown was first described in 1758 by the "father of taxonomy
", Carolus Linnaeus
, in the 10th edition
of his book Systema Naturae
.
and anal fins, the second ray on each fin being many times longer than the surrounding rays. This gives the dorsal and anal fins a noticeably scythe
-like shape. Also, the dorsal fin of the lookdown has 9 spines
and 23 rays, while the anal fin has only 3 spines and 18 rays. The lookdown, like the Atlantic moonfish, had a deep, rhombus
-shaped, laterally-compressed body. The head has the mouth set low and the eye
s high. The overall profile of a lookdown's head is concave. The caudal fin of the lookdown is forked, as in the Pompano
s, while the pectoral fin is similar to a scythe and reaches the middle of the second of the lookdown's dorsal fin.
Lookdown are usually described as being silver
y on both sides with darker tints on top. Young lookdown have several faint, vertical bars that fade as the fish grows. The longest lookdown known was 48.3 cm long, the heaviest known lookdown weighed 2.1 kg.
and Maine
south to Uruguay
, which includes Bermuda
and the Gulf of Mexico
. Although lookdown are common in tropical, Atlantic waters, they are rarely seen in the Greater Antilles
.
Lookdown are found in both marine
and brackish waters at depths of 1 to 53 meters. They usually live in shallow water near the coast
, along hard or sand
y bottoms. Juveniles may be seen in estuaries
or near sandy beach
es Lookdown usually swim together in shoals
, but they often break away into smaller groups or even in pairs.
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...
family
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...
. The lookdown was first described in 1758 by the "father of taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
", Carolus Linnaeus
Carolus Linnaeus
Carl 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...
, in the 10th edition
Edition
In printmaking, an edition is a number of prints struck from one plate, usually at the same time. This is the meaning covered by this article...
of his book Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
.
Description
Although the lookdown is similar to the Atlantic moonfish, it can be distinguished by its dorsalDorsal 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...
and anal fins, the second ray on each fin being many times longer than the surrounding rays. This gives the dorsal and anal fins a noticeably scythe
Scythe
A scythe is an agricultural hand tool for mowing grass, or reaping crops. It was largely replaced by horse-drawn and then tractor machinery, but is still used in some areas of Europe and Asia. The Grim Reaper is often depicted carrying or wielding a scythe...
-like shape. Also, the dorsal fin of the lookdown has 9 spines
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...
and 23 rays, while the anal fin has only 3 spines and 18 rays. The lookdown, like the Atlantic moonfish, had a deep, rhombus
Rhombus
In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...
-shaped, laterally-compressed body. The head has the mouth set low and the eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
s high. The overall profile of a lookdown's head is concave. The caudal fin of the lookdown is forked, as in the Pompano
Pompano
Pompanos are marine fishes in the Trachinotus genus of the Carangidae family . Pompano may also refer to various other, similarly shaped members of Carangidae, or the order Perciformes. Their appearance is deep bodied and mackerel-like, typically silver and toothless with a forked tail and...
s, while the pectoral fin is similar to a scythe and reaches the middle of the second of the lookdown's dorsal fin.
Lookdown are usually described as being silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
y on both sides with darker tints on top. Young lookdown have several faint, vertical bars that fade as the fish grows. The longest lookdown known was 48.3 cm long, the heaviest known lookdown weighed 2.1 kg.
Distribution and habitat
In the western Atlantic, the lookdown is found from CanadaCanada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
and Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
south to Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
, which includes Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
and the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
. Although lookdown are common in tropical, Atlantic waters, they are rarely seen in the Greater Antilles
Greater Antilles
The Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...
.
Lookdown are found in both marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
and brackish waters at depths of 1 to 53 meters. They usually live in shallow water near the coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
, along hard or sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
y bottoms. Juveniles may be seen in estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
or near sandy beach
Beach
A beach is a geological landform along the shoreline of an ocean, sea, lake or river. It usually consists of loose particles which are often composed of rock, such as sand, gravel, shingle, pebbles or cobblestones...
es Lookdown usually swim together in shoals
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
, but they often break away into smaller groups or even in pairs.
External links
- http://www.thejump.net/id/lookdown.htm
- http://www.gma.org/fogm/Selene_vomer.htm
- http://www.fishbase.org/Summary/SpeciesSummary.php?id=1004