![Male whale shark at Georgia Aquarium](https://upload.wikimedia.org/wikipedia/commons/a/a1/Male_whale_shark_at_Georgia_Aquarium.jpg)
Several species of
shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...
s are kept in
captivity
Captivity, or being held captive, is a state wherein humans or other animals are confined to a particular space and prevented from leaving or moving freely. An example in humans is imprisonment. Prisoners of war are usually held in captivity by a ...
in public aquaria. In home aquaria, size constraints mean that only the smallest sharks are typically viable as pets.
Public aquaria
Until recently only a few
benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...
species of shark, such as
horn shark
The horn shark (''Heterodontus francisci'') is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are se ...
s,
leopard sharks,
catshark
Catsharks are ground sharks of the family Scyliorhinidae. They are the largest family of sharks with around 160 species placed in 17 genera. Although they are generally known as catsharks, some species can also be called dogfish due to previous n ...
s, and
zebra shark
The zebra shark (''Stegostoma tigrinum'') is a species of carpet shark and the sole member of the family Stegostomatidae. It is found throughout the tropical Indo-Pacific, frequenting coral reefs and sandy flats to a depth of . Adult zebra sharks ...
s, had survived in aquarium conditions for up to a year or more. This gave rise to the belief that sharks, as well as being difficult to capture and transport, were difficult to care for. A better knowledge of sharks has led to more species (including the large
pelagic
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...
sharks) being able to be kept for far longer. At the same time, transportation techniques have improved and long distance movement of sharks is becoming easier. Several attempts to keep a
great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is nota ...
in captivity have been made, but most specimens died or had to be released after a short time. One example, placed in the
Okinawa Churaumi Aquarium
The , formerly known as the Okinawa Ocean Expo Aquarium, is located within the Ocean Expo Park in Okinawa, Japan. It is a member of the Japanese Association of Zoos and Aquariums (JAZA), and was the largest aquarium in the world until it was surp ...
in Japan, only survived for three days. The longest a great white was held in captivity was at the
Monterey Bay Aquarium
Monterey Bay Aquarium is a nonprofit public aquarium in Monterey, California. Known for its regional focus on the marine habitats of Monterey Bay, it was the first to exhibit a living kelp forest when it opened in October 1984. Its biologists ...
, in September 2004. A young female was kept in an outdoor tank for 44 days before releasing her back into the wild. In the following years, the Monterey Bay Aquarium hosted five more juvenile white sharks for temporary stays before ending its program in 2011.
Behavior
When introduced to their new habitat some mature sharks have refused food despite the abundance and variety of feeding methods used.
[Essapian, F. (1962). Notes on the Behavior of Sharks in Captivity. Copeia, 1962(2), 457-459. doi:10.2307/1440936]
Sharks are usually seen to live a solitary existence, rarely moving about in group events, although, a tank could house up to four or five species during the same time period.
It has been commonly seen that
lemon
The lemon (''Citrus limon'') is a species of small evergreen trees in the flowering plant family Rutaceae, native to Asia, primarily Northeast India (Assam), Northern Myanmar or China.
The tree's ellipsoidal yellow fruit is used for culin ...
and
nurse sharks
The Ginglymostomatidae are a cosmopolitan family of carpet sharks known as nurse sharks, containing four species in three genera. Common in shallow, tropical and subtropical waters, these sharks are sluggish and docile bottom-dwellers. occupy the bottom of the tank floor. Occasionally, they will take a swim no more than two or three feet off the bottom.
Bull sharks
The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in riv ...
,
sandbar shark
The sandbar shark (''Carcharhinus plumbeus'') also known as the brown shark or thickskin shark, is a species of requiem shark, and part of the family Carcharhinidae, native to the Atlantic Ocean and the Indo-Pacific. It is distinguishable by its ...
s, and
sand tiger shark
The sand tiger shark (''Carcharias taurus''), gray nurse shark, spotted ragged-tooth shark or blue-nurse sand tiger, is a species of shark that inhabits subtropical and temperate waters worldwide. It inhabits the continental shelf, from sandy sho ...
s continuously swim at mid-depth. Larger tiger sharks inhabit the upper region of the tank where their dorsal fin is breaking the surface frequently.
Swimming patterns seen from sharks in captivity are that of
blacktip, bull, and lemon sharks being active 24 hours and those of sandbars, nurse and sand tigers being active at certain times of the day/night.
[Hussain, S. M. (1991). The Behavior of Sharks in Captivity. Indian Journal of Fishtrits. Retrieved April 30, 2018.] However, within some aquaria this could be attributed to the different feeding times of these species.
In captivity, sandbar, sand tiger, and nurse sharks are predicted to be less aggressive in that no aggressive biting is seen after feeding.
[Flunory, M., Ortiz, M., & Restrepo, A. (n.d.). A Behavioral Study of Sharks in Captivity. Retrieved April 30, 2018.] The foremost behavior observed from those in captivity was curiosity, reasoning's being due to less competition for food and lack of stimulation.
Home aquaria
Most species of shark are not suitable for domestic aquaria and not every species of shark sold by pet stores make good inhabitants for personal aquaria. Some species of sharks can also be kept well in home saltwater aquaria.
Uninformed or unscrupulous dealers sometimes sell juvenile sharks like the
nurse shark
The nurse shark (''Ginglymostoma cirratum'') is an elasmobranch fish in the family Ginglymostomatidae. The conservation status of the nurse shark is globally assessed as Vulnerable in the IUCN List of Threatened Species. They are considered t ...
, which upon reaching adulthood will have far outgrown typical home aquaria.
Public aquaria are generally not interested in accepting donated specimens that have overgrown their housing and some shark owners have been tempted to
release
Release may refer to:
* Art release, the public distribution of an artistic production, such as a film, album, or song
* Legal release, a legal instrument
* News release, a communication directed at the news media
* Release (ISUP), a code to ident ...
them into the wild.
Housings
However, some species of shark can make prized additions to home aquaria.
Species appropriate to home aquaria represent considerable spatial and financial investments as they generally approach adult lengths of 3 feet and can live up to 25 years.
Sharks must be housed in aquaria at or exceeding 180 gallons in volume, with more active species requiring more space.
Surface area is an even more significant consideration for aquarists than volume as it is the determining factor for the amount of oxygen that ends up being dissolved in the water, and therefore critical to the sharks' respiration.
Choice of aquarium substrate is also important because a sharp, rough bed can irritate a shark's soft underbelly, or in severe cases lead to fatal infections.
Shark aquaria are generally advised to be decorated "conservatively" in order to leave space for the animal to move more freely during daily activities. A cave, however, is often an appropriate addition for some shy species.
Diet and nutrition
Sharks are very frequently overfed by amateur aquarists, which can lead to obesity or unnaturally fast growth rates.
Captive sharks are healthiest when fed at levels similar to their food intake in the wild.
Usually this amounts to 1-3% of their body weight weekly.
However, aquarium conditions and species disposition are considered by conscientious aquarists when feeding captive sharks.
Relatively sedentary species, such as wobbegongs can live on feedings occurring once or twice weekly.
More active species may require to be fed three or four times per week to maintain satisfactory health.
Sharks living in cooler water have slower metabolisms than sharks in warmer water housings and therefore require less food.
The most common staple food provided to captive sharks in home aquaria is frozen fish.
The freezing process used to store foods for sharks often results in the food items losing nutrient value.
Lost nutrients are replaced by vitamin supplements, which are marketed commercially, sometimes by companies generally associated with more typical pet foods (such as
Purina Mills
Purina Mills, LLC is the farm animal feeds unit of Land O' Lakes. It was previously part of Ralston Purina, until the U.S. animal feeds portion was first sold in 1986.
History
Purina traces its roots back to 1894, when founder William H. Danfo ...
).
Uncorrected nutrient deficiencies inherent in the frozen food diet can cause considerable detriment to the health of captive specimens.
Conditions such as popeye, ascites, and anemia are known to occur in captive sharks that are deficient in some essential vitamin.
Vitamin B deficiency results in a treatable condition where the shark's back arches and it swims in a circular motion.
Feeding sharks frozen non-marine fish can result in deficiencies of omega-3 fatty acids, which can result in "fat infiltration of the liver," which can impede the organ's function seriously enough for major health issues.
In community tanks
Sometimes sharks are unwittingly put in harm's way when aquarists include potentially dangerous tankmates in the same aquarium.
Hobbyists generally don't think of other fish being a threat to sharks, but triggerfish, angel fish, puffers, and wrasses can all injure them.
A large grouper is capable of consuming smaller sharks.
Sometimes docile bottom feeding sharks are put at risk because of the fish that feed on the ocean bottom, sedentary sharks are simply an extension of the substrate."
Another problem aquarists keeping sharks with other types of fish have encountered is that the smaller, more passive aquarium-friendly shark species often have difficulty competing with their tankmates for the food provided by the aquarist.
Sharks are predatory themselves and may maul or consume tankmates smaller or weaker than themselves.
See also
*
Aquarium
An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...
References
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Sharks
Aquariums