Hawkfish
Encyclopedia
Hawkfish are strictly tropical, perciform marine fish
of the family Cirrhitidae. Associated with the coral reef
s of the western and eastern Atlantic
and Indo-Pacific
, the hawkfish family contains 12 genera and 32 species. They share many morphological features with the scorpionfish
of the family Scorpaenidae.
Hawkfish have large heads with thick, somewhat elongate bodies. Their dorsal fins are merged, with the first consisting of ten connected spines. At the tip of each spine are several trailing filaments, hence the family name Cirrhitidae, from the Latin
cirrus meaning "fringe." Their tail fins are rounded and truncate and their pectoral fins are enlarged and skinless. Their scales may be cycloid
or ctenoid. Most hawkfish are small, from about 7-15 centimetres in length. The largest species, the giant hawkfish
(Cirrhitus rivulatus) attains a length of 60 centimetres and a weight of 4 kilograms. A commercial fishery
exists for the larger species as they are considered excellent food fishes.
The vibrant colours exhibited by most hawkfish have won them popularity in the aquarium
hobby, aided by the fishes' reputation for unproblematic upkeep and easy acclimation to tank life. Popularly kept species include the longnose hawkfish (Oxycirrhites typus), coloured in a red and pink crosshatch pattern, and the flame hawkfish (Neocirrhites armatus).
Thanks to their large, skinless pectoral fins, hawkfish are able to perch upon fire coral
s without incurring harm. Actually hydrozoa
ns rather than true coral
s, fire corals possess stinging cells called nematocysts which would normally prevent close contact. Afforded some degree of protection by their living perches, hawkfish seek the high ground of the reef where they warily survey their surroundings; redolent of a hawk
's behaviour, this habit inspired their common name.
Most hawkfish are solitary in nature but some will form pairs and share a head of coral. Other species form harems of up to seven females dominated by a larger male. They are diurnal
and remain within the shallows of the reef, no deeper than 30 metres. Typically motionless, hawkfish will dart out to grab crustacean
s and other small invertebrate
s which happen to pass by.
Spawning occurs at night, at or near the water's surface. Hawkfish are pelagic spawners; that is, they release many tiny buoyant eggs which drift with the ocean currents until hatching. Hatching is thought to happen after about three weeks; the distance travelled in this time may explain the exceptionally wide distribution of hawkfish. They have not been successfully bred in the aquarium, with the exception of the longnose hawkfish.
Hawkfish are noted for their protogynous hermaphrodism
: functional females will change into males if the dominant supermale dies. Hawkfish are generally not sexually dichromatic, meaning the sexes cannot be distinguished by coloration alone.
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...
of the family Cirrhitidae. Associated with the coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s of the western and eastern 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...
and Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, the hawkfish family contains 12 genera and 32 species. They share many morphological features with the scorpionfish
Scorpionfish
Scorpaenidae, the scorpionfish, are a family of mostly marine fish that includes many of the world's most venomous species. As the name suggests, scorpionfish have a type of "sting" in the form of sharp spines coated with venomous mucus. The family is a large one, with hundreds of members. They are...
of the family Scorpaenidae.
Hawkfish have large heads with thick, somewhat elongate bodies. Their dorsal fins are merged, with the first consisting of ten connected spines. At the tip of each spine are several trailing filaments, hence the family name Cirrhitidae, from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
cirrus meaning "fringe." Their tail fins are rounded and truncate and their pectoral fins are enlarged and skinless. Their scales may be cycloid
Cycloid
A cycloid is the curve traced by a point on the rim of a circular wheel as the wheel rolls along a straight line.It is an example of a roulette, a curve generated by a curve rolling on another curve....
or ctenoid. Most hawkfish are small, from about 7-15 centimetres in length. The largest species, the giant hawkfish
Giant hawkfish
Giant Hawkfish, Cirrhitus rivulatus is a subspecies of hawkfish. It is a marine fish and remains the largest of the Hawkfish family, scoring in a maximum size of 60 cm . It is known for its social behavior towards scuba divers and its uncanny ability to perch on its pectoral fins...
(Cirrhitus rivulatus) attains a length of 60 centimetres and a weight of 4 kilograms. A commercial fishery
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,...
exists for the larger species as they are considered excellent food fishes.
The vibrant colours exhibited by most hawkfish have won them popularity in the aquarium
Aquaria
Aquaria may refer to:*Aquarium, in the plural*Aquaria , a computer game*Aquaria , a Brazilian metal band*Aquaria, one of the Twelve Colonies in Battlestar Galactica...
hobby, aided by the fishes' reputation for unproblematic upkeep and easy acclimation to tank life. Popularly kept species include the longnose hawkfish (Oxycirrhites typus), coloured in a red and pink crosshatch pattern, and the flame hawkfish (Neocirrhites armatus).
Fire coral
Fire corals are colonial marine organisms that look rather like real coral. However they are technically not corals; they are actually more closely related to jellyfish and other stinging anemones...
s without incurring harm. Actually hydrozoa
Hydrozoa
Hydrozoa are a taxonomic class of very small, predatory animals which can be solitary or colonial and which mostly live in saltwater. A few genera within this class live in freshwater...
ns rather than true coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
s, fire corals possess stinging cells called nematocysts which would normally prevent close contact. Afforded some degree of protection by their living perches, hawkfish seek the high ground of the reef where they warily survey their surroundings; redolent of a hawk
Hawk
The term hawk can be used in several ways:* In strict usage in Australia and Africa, to mean any of the species in the subfamily Accipitrinae, which comprises the genera Accipiter, Micronisus, Melierax, Urotriorchis and Megatriorchis. The large and widespread Accipiter genus includes goshawks,...
's behaviour, this habit inspired their common name.
Most hawkfish are solitary in nature but some will form pairs and share a head of coral. Other species form harems of up to seven females dominated by a larger male. They are diurnal
Diurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
and remain within the shallows of the reef, no deeper than 30 metres. Typically motionless, hawkfish will dart out to grab 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 and other small invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s which happen to pass by.
Spawning occurs at night, at or near the water's surface. Hawkfish are pelagic spawners; that is, they release many tiny buoyant eggs which drift with the ocean currents until hatching. Hatching is thought to happen after about three weeks; the distance travelled in this time may explain the exceptionally wide distribution of hawkfish. They have not been successfully bred in the aquarium, with the exception of the longnose hawkfish.
Hawkfish are noted for their protogynous hermaphrodism
Hermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
: functional females will change into males if the dominant supermale dies. Hawkfish are generally not sexually dichromatic, meaning the sexes cannot be distinguished by coloration alone.