Threatened species

Threatened species are any species (including animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of critical depensation, a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment.[1]

Conservation status
Bufo periglenes, the Golden Toad, was last recorded on May 15, 1989
Lower Risk

Other categories

Related topics

IUCN Red List category abbreviations (version 3.1, 2001)

NatureServe category abbreviations

IUCN definition

The International Union for Conservation of Nature (IUCN) is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened:

Less-than-threatened categories are near threatened, least concern, and the no longer assigned category of conservation dependent. Species which have not been evaluated (NE), or do not have sufficient data (data deficient) also are not considered "threatened" by the IUCN.

Status iucn3.1 threatened
The three categories of the threatened species IUCN Red List.

Although threatened and vulnerable may be used interchangeably when discussing IUCN categories, the term threatened is generally used to refer to the three categories (critically endangered, endangered and vulnerable), while vulnerable is used to refer to the least at risk of those three categories. They may be used interchangeably in most contexts however, as all vulnerable species are threatened species (vulnerable is a category of threatened species); and, as the more at-risk categories of threatened species (namely endangered and critically endangered) must, by definition, also qualify as vulnerable species, all threatened species may also be considered vulnerable.

Threatened species are also referred to as a red-listed species, as they are listed in the IUCN Red List of Threatened Species.

Subspecies, populations and stocks may also be classified as threatened.

United States definition

Status ESA LT
"Threatened" in relation to "endangered" under the ESA.

Under the Endangered Species Act in the United States, "threatened" is defined as "any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range".[2] It is the less protected of the two protected categories. The Bay checkerspot butterfly (Euphydryas editha bayensis) is an example of a threatened subspecies protected under the ESA.

Within the U.S., state wildlife agencies have the authority under the ESA to manage species which are considered endangered or threatened within their state but not within all states, and which therefore are not included on the national list of endangered and threatened species. For example, the trumpeter swan (Cygnus buccinator) is threatened in the state of Minnesota, while large populations still remain in Canada and Alaska.[3]

Australian definition

The Commonwealth of Australia has legislation for categorising and protecting endangered species, namely the Environment Protection and Biodiversity Conservation Act 1999, which is known in short as the EPBC Act. This act has six categories;[4] extinct, extinct in the wild, critically endangered, endangered, vulnerable, and conservation dependent, defined in Section 179 of the act, and could be summarised as;

  • "Extinct" - "no reasonable doubt that the last member of the species has died",
  • "Extinct in the wild" - "known only to survive in cultivation" and "despite exhaustive surveys" has not been seen in the wild,
  • "Critically endangered" - "extremely high risk of extinction in the wild in the immediate future",
  • "Endangered" - "very high risk of extinction in the wild in the near future",
  • "Vulnerable" - "high risk of extinction in the wild in medium-term future", and
  • "Conservation dependent" - "focus of a specific conservation program" without which the species would enter one of the above categories.

The EPBC Act also recognises and protects threatened ecosystems such as plant communities, and Ramsar Convention wetlands used by migratory birds.

Individual states and territories of Australia are bound under the EPBC Act, but may also have legislation which gives further protection to certain species, for example Western Australia's Wildlife Conservation Act 1950. Some species, such as Lewin's rail (Lewinia pectoralis), are not listed as threatened species under the EPBC Act, but they may be recognised as threatened by individual states or territories.

NSW Definition

Threatening Processes

Pests and weeds, climate change and habitat loss are some of the key threatening processes facing native plants and animals listed by the NSW Office of Environment and Heritage.

See also

Notes and references

  1. ^ Liermann, Martin (2001). "Depensation: evidence, models and implications" (PDF). Fish and Fisheries.
  2. ^ Program, U.S. Fish and Wildlife Service/Endangered Species. "Endangered Species Program - Laws & Policies - Endangered Species Act - Section 3 Definitions". Archived from the original on 29 April 2017. Retrieved 8 May 2018.
  3. ^ "Minnesota Endangered & Threatened Species List" (PDF). Archived (PDF) from the original on 19 May 2017. Retrieved 8 May 2018.
  4. ^ Threatened species under the Environment Protection and Biodiversity Conservation Act 1999 Archived 2009-02-21 at the Wayback Machine

Further reading


ARKive was a global initiative with the mission of "promoting the conservation of the world's threatened species, through the power of wildlife imagery", which it did by locating and gathering films, photographs and audio recordings of the world's species into a centralised digital archive. Its priority was the completion of audio-visual profiles for the c. 17,000 species on the IUCN Red List of Threatened Species.The project was an initiative of Wildscreen, a UK-registered educational charity, based in Bristol. The technical platform was created by Hewlett Packard, as part of the HP Labs' Digital Media Systems research programme.ARKive had the backing of leading conservation organisations, including BirdLife International, Conservation International, International Union for Conservation of Nature (IUCN), The United Nations' World Conservation Monitoring Centre (UNEP-WCMC), and the World Wide Fund for Nature (WWF), as well as leading academic and research institutions, such as the Natural History Museum; Royal Botanic Gardens, Kew; and the Smithsonian Institution. It was a member of the Institutional Council of the Encyclopedia of Life.Two ARKive layers for Google Earth, featuring endangered species and species in the Gulf of Mexico were produced by Google Earth Outreach. The first of these was launched in April 2008 by Wildscreen's Patron, Sir David Attenborough.The website closed on 15 February 2019; its collection of images and videos remains securely stored, in perpetuity.

Conservation status

The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation status: not simply the number of individuals remaining, but the overall increase or decrease in the population over time, breeding success rates, and known threats. Various systems of conservation status exist and are in use at international, multi-country, national and local levels as well as for consumer use.

Critically endangered

A critically endangered (CR) species is one that has been categorized by the International Union for Conservation of Nature (IUCN) as facing an extremely high risk of extinction in the wild.As of 2014, there are 2,464 animal and 2,104 plant species with this assessment.As the IUCN Red List does not consider a species extinct until extensive, targeted surveys have been conducted, species that are possibly extinct are still listed as critically endangered. IUCN maintains a list of "possibly extinct" CR(PE) and "possibly extinct in the wild" CR(PEW) species, modelled on categories used by BirdLife International to categorize these taxa.

Endangered species

An endangered species is a species which has been categorized as very likely to become extinct. Endangered (EN), as categorized by the International Union for Conservation of Nature (IUCN) Red List, is the second most severe conservation status for wild populations in the IUCN's schema after Critically Endangered (CR).

In 2012, the IUCN Red List featured 3079 animal and 2655 plant species as endangered (EN) worldwide. The figures for 1998 were, respectively, 1102 and 1197.

Many nations have laws that protect conservation-reliant species: for example, forbidding hunting, restricting land development or creating preserves. Population numbers, trends and species' conservation status can be found at the lists of organisms by population.


Felidae is a family of mammals in the order Carnivora, colloquially referred to as cats. A member of this family is also called a felid. The term "cat" refers both to felids in general and specifically to the domestic cat (Felis catus).Reginald Innes Pocock divided the extant Felidae into three subfamilies: the Pantherinae, the Felinae and the Acinonychinae, differing from each other by the ossification of the hyoid apparatus and by the cutaneous sheaths which protect their claws.

This concept has been revised following developments in molecular biology and techniques for analysis of morphological data. Today, the living Felidae are divided in two subfamilies, with the Pantherinae including seven Panthera and two Neofelis species. The Felinae include all the non-pantherine cats with 10 genera and 34 species.The first cats emerged during the Oligocene, about 25 million years ago, with the appearance of Proailurus and Pseudaelurus. The latter species complex was ancestral to two main lines of felids: the cats in the extant subfamilies and a third major group of extinct cats of the subfamily Machairodontinae. The machairodonts included the saber-toothed cats such as the Smilodon. The "false sabre toothed cats", the Barbourofelidae and Nimravidae, are not true cats, but are closely related and together with Felidae and other cat-like carnivores (hyaenas, viverrids and mongooses) make up the feliform carnivores.The characteristic features of cats have evolved to support a carnivorous lifestyle, with adaptations for ambush or stalking and short pursuit hunting. They have slender muscular bodies, strong flexible forelimbs and retractable claws for holding prey, dental and cranial adaptations for a strong bite, and often have characteristic striped or spotted coat patterns for camouflage.


Herring are forage fish, mostly belonging to the family Clupeidae.

Herring often move in large schools around fishing banks and near the coast. The most abundant and commercially important species belong to the genus Clupea, found particularly in shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of Clupea are recognised, and provide about 90% of all herrings captured in fisheries. Most abundant of all is the Atlantic herring, providing over half of all herring capture. Fishes called herring are also found in the Arabian Sea, Indian Ocean, and Bay of Bengal.

Herring played a pivotal role in the history of marine fisheries in Europe, and early in the 20th century, their study was fundamental to the evolution of fisheries science. These oily fish also have a long history as an important food fish, and are often salted, smoked, or pickled.

Himalayan serow

The Himalayan serow (Capricornis thar) is a goat-antelope native to the eastern Himalayas and eastern and southeastern Bangladesh. It is listed as Near Threatened on the IUCN Red List because the population is considered to be declining due to habitat loss and hunting for its meat.

IUCN Red List

The IUCN Red List of Threatened Species (also known as the IUCN Red List or Red Data List), founded in 1965, has evolved to become the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world, With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red List are produced by countries or organizations, which assess the risk of extinction to species within a political management unit.

The IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. The aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. According to the International Union for Conservation of Nature (IUCN) (1996), the formally stated goals of the Red List are (1) to provide scientifically based information on the status of species and subspecies at a global level, (2) to draw attention to the magnitude and importance of threatened biodiversity, (3) to influence national and international policy and decision-making, and (4) to provide information to guide actions to conserve biological diversity.Major species assessors include BirdLife International, the Institute of Zoology (the research division of the Zoological Society of London), the World Conservation Monitoring Centre, and many Specialist Groups within the IUCN Species Survival Commission (SSC). Collectively, assessments by these organizations and groups account for nearly half the species on the Red List.

The IUCN aims to have the category of every species re-evaluated every five years if possible, or at least every ten years. This is done in a peer reviewed manner through IUCN Species Survival Commission (SSC) Specialist Groups, which are Red List Authorities responsible for a species, group of species or specific geographic area, or in the case of BirdLife International, an entire class (Aves).As of 2018, 26,197 species are now classified as vulnerable, critical or endangered.

Least-concern species

A least concern (LC) species is a species which has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated but not qualified for any other category. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent.

Species cannot be assigned the Least Concern category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status.

Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). However, around 20% of least concern taxa (3261 of 15636) in the IUCN database use the code "LR/lc", which indicates they have not been re-evaluated since 2000. Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc.

While "least concern" is not considered a red listed category by the IUCN, the 2006 IUCN Red List still assigns the category to 15636 taxa. The number of animal species listed in this category totals 14033 (which includes several undescribed species such as a frog from the genus Philautus). There are also 101 animal subspecies listed and 1500 plant taxa (1410 species, 55 subspecies, and 35 varieties). There are also two animal subpopulations listed: the Australasian and Southern African subpopulations of spiny dogfish. No fungi or protista have the classification, though only four species in those kingdoms have been evaluated by the IUCN. Humans qualify for this category, and in 2008 were formally assessed as such by the IUCN.

List of birds by population

This is a list of bird species by global population, divided by bird classification. While numbers are estimates, they have been made by the experts in their fields. For more information on how these estimates were ascertained, see Wikipedia's articles on population biology and population ecology. Contributing organizations include the IUCN, BirdLife International, and Partners in Flight.

This list is incomplete, because experts have not estimated all bird numbers. For example, the spectacled flowerpecker was only discovered in 2010, and has yet to be classified with a Linnean name, but would add to the other 73 new bird species described by ornithologists from 2000 – 2009. Global population estimates for many of these at this time would lack accuracy.

All numbers are estimates, because they are taken by observation, and a given number of 50 slender-billed curlews does not necessarily mean there are 10 more of this species than the black stilt, which has been estimated at 40: there is a possibility that the latter species has a larger population than the former. This list should not be taken that literally. An estimate of 250 shore dotterels compared with 4,500 – 5,000 wrybills, on the other hand, means that the latter has well over one order of magnitude more individuals than the former. The wrybill only has approximately one tenth the population of great skuas (48,000), which are outnumbered ~10:1 by the pigeon guillemot (470,000). It is these large differences between species that this list tries to convey.

List of threatened rays

Threatened rays are those vulnerable to endangerment (extinction) in the near future. The International Union for Conservation of Nature (IUCN) is the world's oldest global environmental organisation. It evaluates threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened:

Vulnerable species

Endangered species

Critically endangered speciesThe term threatened strictly refers to these three categories (critically endangered, endangered and vulnerable), while vulnerable is used to refer to the least at risk of these categories. The terms can be used somewhat interchangeably, as all vulnerable species are threatened, all endangered species are vulnerable and threatened, and all critically endangered species are endangered, vulnerable and threatened. Threatened species are also referred to as a red-listed species, as they are listed in the IUCN Red List of Threatened Species.Together rays and sharks make up the class of modern cartilaginous fishes. Modern fish are either cartilaginous or bony. Cartilaginous fishes have skeletons made of cartilage while bony fishes have skeletons made of bone. Because rays and sharks are closely related, they are often studied together. In 2010 a global IUCN study of vertebrates found that of 1,044 cartilaginous (ray and shark) species examined, 345 or 33% were threatened with extinction.There are four orders of rays: stingrays, skates, electric rays and sawfishes. Like sharks, rays are relatively long living and thrive in stable populations. They are K-strategists which grow slowly, mature late sexually and produce few offspring. They cannot recover as rapidly as many faster growing fish can if their populations are depleted. As with sharks, rays are increasingly becoming vulnerable because of commercial and recreational fishing pressures, the impact of non-ray fisheries on the seabed and ray prey species, and other habitat alterations such as damage and loss from coastal development and marine pollution. Most particularly, the continuing decline of threatened rays and sharks is the consequence of unregulated fishing.

Manta rays are largest rays in the world, with wingspans reaching 7 metres. They have one of the highest brain-to-body mass ratios of all fish. Manta populations suffer when they are caught as bycatch by fishermen fishing for other species, but fisheries which target manta rays are even more harmful. Manta rays use their gills to filter plankton from the sea. Demand for their dried gill rakers, cartilaginous structures protecting the gills, has been growing in traditional Chinese medicine practices. The market is "bogus" since dried manta gills have never been used historically in Chinese medicine, and there is no evidence that the gills have any medicinal value. The flesh is edible and is consumed in some countries, but is tough and unattractive compared to other fish. To fill the growing demand in Asia for gill rakers, targeted fisheries have developed in other parts of the world, including Sri Lanka, Indonesia, West Africa and Central and South America. Each year, thousands of manta rays, primarily the giant manta ray, are being caught and killed purely for their gill rakers. A fisheries study in Sri Lanka estimated that over a thousand of these were being sold in the country's fish markets each year.In 2011, manta rays became strictly protected in international waters thanks to their recent inclusion in the Convention on Migratory Species of Wild Animals. The CMS is an international treaty organization concerned with conserving migratory species and habitats on a global scale. Although individual nations were already protecting manta rays, the fish often migrate through unregulated waters, putting them at increased risk from overfishing. In 2013, the Convention on International Trade in Endangered Species (CITES) listed both species of manta rays as CITES Appendix II species. This means that the international trade of manta rays will now be monitored and regulated.Sawfish are a less well known family of rays which have a long rostrum resembling a saw. Some species can reach 7 metres or 23 feet in length. All species of sawfish are either endangered or critically endangered as a result of habitat destruction and overfishing. Their young stay close to shore, and are particularly affected by coastal developments. Because their rostrum is easily entangled, sawfishes can easily become bycatch in fishing nets. They are also exploited for the novelty value of their rostrum, their fins are eaten as a delicacy in China, and their liver oil used as a food supplement. While arguing for a global ban on international commerce in 2007, a representative from the National Museums of Kenya stated, "Only the meat is consumed locally; and artisanal fishermen can retire after catching one sawfish due to the high value of a single rostrum, up to $1,450." In 2013 CITES uplisted the largetooth sawfish to Appendix I. This is CITES highest protection level, and means that all international trade of the species is banned.

List of threatened sharks

Threatened sharks are those vulnerable to endangerment (extinction) in the near future. The International Union for Conservation of Nature (IUCN) is the world's oldest global environmental organization. It evaluates threatened species, and treats threatened species not as a single category, but as a group of three categories, depending on the degree to which they are threatened:

Vulnerable species

Endangered species

Critically endangered speciesThe term threatened strictly refers to these three categories (critically endangered, endangered and vulnerable), while vulnerable is used to refer to the least at risk of these categories. The terms can be used somewhat interchangeably, as all vulnerable species are threatened, all endangered species are vulnerable and threatened, and all critically endangered species are endangered, vulnerable and threatened. Threatened species are also referred to as a red-listed species, as they are listed in the IUCN Red List of Threatened Species.

Shark species are increasingly becoming threatened because of commercial and recreational fishing pressures, the impact of non-shark fisheries on the seabed and shark prey species, and other habitat alterations such as damage and loss from coastal development and marine pollution. Rising demands for shark products has increased pressure on shark fisheries, but little monitoring or management occurs of most fisheries. Major declines in shark stocks have been recorded over the past few decades; some species had declined over 90% and population declines of 70% were not unusual by 1998. In particular, harvesting young sharks before they reproduce severely impacts future populations. Sharks generally reach sexual maturity only after many years and produce few offspring in comparison to other fish species.Conservationists estimate that up to 100 million sharks are killed by commercial and recreational fishing every year. Sharks are often killed for shark fin soup, which some Asian countries regard as a status symbol. Fishermen capture live sharks, fin them, and dump the finless animal back into the water to die from suffocation or predators. Sharks are also killed for their flesh in Europe and elsewhere. The 2007 film Sharkwater documents ways in which sharks are being hunted to extinction. In 2009, the IUCN Shark Specialist Group reported on the conservation status of pelagic (open water) sharks and rays. They found that over half the pelagic sharks targeted by high-seas fisheries were threatened with extinction.In 2010, the Convention on International Trade in Endangered Species (CITES) rejected proposals from the United States and Palau that would have required countries to strictly regulate trade in several species of hammerhead, oceanic whitetip and dogfish sharks. The majority, but not the required two-thirds of voting delegates, approved the proposal. China, by far the world's largest shark consumer, and Japan, which battles all attempts to extend the Convention's protections to marine species, led the opposition.In 2013, CITES member nations overcame the continued opposition led by China and Japan, and reversed course. In what CITES has called a "milestone", the oceanic whitetip, porbeagle, and three species of hammerheads will now join the great white, basking and whale shark on CITES Appendix II, effective September 2014. International trade of these species is thus prohibited without CITES permits, "... and evidence will have to be provided that they are harvested sustainably and legally."In 2014 the state government of Western Australia led by Premier Colin Barnett implemented a policy of killing large sharks. The policy is intended to protect users of the marine environment from shark attack following the deaths of seven people on the Western Australian coastline in the years 2010 to 2013. Baited drum lines are deployed near popular beaches using hooks designed to catch the vulnerable great white shark, as well as bull and tiger sharks. Large sharks found hooked but still alive are shot and their bodies discarded at sea. The government claims they are not culling sharks, but are using a "targeted, localised, hazard mitigation strategy". Barnett has described opposition to killing the sharks as "ludicrous" and "extreme", and said that nothing can change his mind.

Lists of IUCN Red List near threatened species

On 12 March 2010, the IUCN Red List of Threatened Species identified 3829 (2657 Animalia, 1172 Plantae) near threatened species, subspecies and varieties, stocks and sub-populations.

For IUCN lists of near threatened species by kingdom, see:

Animals (kingdom Animalia) — IUCN Red List near threatened species (Animalia)

Amphibians — List of near threatened amphibians

Birds — List of near threatened birds

Fish — List of near threatened fishes

Invertebrates — List of near threatened invertebrates

Arthropods — List of near threatened arthropods

Insects — List of near threatened insects

Molluscs List of near threatened molluscs

Mammals — List of near threatened mammals

Reptiles — List of near threatened reptiles

Fungi (kingdom Fungi) — IUCN Red List near threatened species (Fungi)

Plants (kingdom Plantae) — IUCN Red List near threatened species (Plantae)


Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment.

Mackerel species typically have vertical stripes on their backs and deeply forked tails. Many are restricted in their distribution ranges and live in separate populations or fish stocks based on geography. Some stocks migrate in large schools along the coast to suitable spawning grounds, where they spawn in fairly shallow waters. After spawning they return the way they came in smaller schools to suitable feeding grounds, often near an area of upwelling. From there they may move offshore into deeper waters and spend the winter in relative inactivity. Other stocks migrate across oceans.

Smaller mackerel are forage fish for larger predators, including larger mackerel and Atlantic cod. Flocks of seabirds, whales, dolphins, sharks, and schools of larger fish such as tuna and marlin follow mackerel schools and attack them in sophisticated and cooperative ways. Mackerel flesh is high in omega-3 oils and is intensively harvested by humans. In 2009, over 5 million tons were landed by commercial fishermen. Sport fishermen value the fighting abilities of the king mackerel.

Near-threatened species

A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status. The IUCN notes the importance of re-evaluating near-threatened taxon at appropriate intervals.

The rationale used for near-threatened taxa usually includes the criteria of vulnerable which are plausible or nearly met, such as reduction in numbers or range. Near-threatened species evaluated from 2001 onwards may also be ones which are dependent on conservation efforts to prevent their becoming threatened, whereas prior to this conservation-dependent species were given a separate category ("Conservation Dependent").

Additionally, the 402 conservation-dependent taxa may also be considered near-threatened.

Red serow

The red serow (Capricornis rubidus) is a goat-antelope thought to be native to southern Bangladesh and northern Burma. It has been considered a subspecies of C. sumatraensis. In the northeastern part of India, the red serow occurs widely in the hills south of the Brahmaputra river. although the IUCN ststes that this species is recorded with certainty only from Myanmar, in Kachin State, and that records in India refer to the Himalayan serow.

Red side-necked turtle

The red side-necked turtle (Rhinemys rufipes), red turtle, red-footed sideneck turtle, William’s toadhead turtle, or red-footed Amazon side-necked turtle is a monotypic species of turtle in the family Chelidae. It is found in Colombia and possibly Peru and Brazil.


Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. Their evolution dates back to the Triassic some 245 to 208 million years ago. The family is grouped into four genera: Acipenser, Huso, Scaphirhynchus and Pseudoscaphirhynchus. Four species may now be extinct. Two closely related species, Polyodon spathula (American paddlefish) and Psephurus gladius (Chinese paddlefish, possibly extinct) are of the same order, Acipenseriformes, but are in the family Polyodontidae and are not considered to be "true" sturgeons. Both sturgeons and paddlefish have been referred to as "primitive fishes" because their morphological characteristics have remained relatively unchanged since the earliest fossil record. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America.Sturgeons are long-lived, late-maturing fishes with distinctive characteristics, such as a heterocercal caudal fin similar to that of sharks, and an elongated spindle-like body that is smooth-skinned, scaleless and armored with 5 lateral rows of bony plates called scutes. Several species can grow quite large, typically ranging 7–12 feet (2-3½ m) in length. The largest sturgeon on record was a Beluga female captured in the Volga estuary in 1827, weighing 1,571 kg (3,463 lb) and 7.2 m (24 ft) long. Most sturgeons are anadromous bottom-feeders which migrate upstream to spawn but spend most of their lives feeding in river deltas and estuaries. Some species inhabit freshwater environments exclusively while others primarily inhabit marine environments near coastal areas, and are known to venture into open ocean.

Several species of sturgeon are harvested for their roe which is processed into caviar—a luxury food and the reason why caviar-producing sturgeons are among the most valuable of all wildlife resources. They are particularly vulnerable to overexploitation and other threats, including pollution and habitat fragmentation. Most species of sturgeon are considered to be at risk of extinction, making them more critically endangered than any other group of species.In art, a sturgeon is the symbol on the coat of arms for Saint Amalberga of Temse.

Yellowspotted catshark

The yellowspotted catshark (Scyliorhinus capensis) is a rare catshark of the family Scyliorhinidae. It is found in the southeast Atlantic, from Lüderitz, Namibia to central Natal, South Africa, between latitudes 0° and 37° S. It can grow up to a length of about 1.22 metres (4 ft 0 in). The reproduction of this catshark is oviparous.

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