There are 120 or so different species of cuttlefish. They range in size from the two-inch “ Metasepia pfefferi” to the three-foot-long “Sepia apama” (giant cuttlefish). They are found in temperate and tropical oceans everywhere except the Americas and prefer coastal environments such as reefs, mangroves and areas of sea grass.
The order of cuttlefish (Sepiida:) are grouped into six families divided between two suborders. One suborder and three families are extinct. 1) Under the Suborder Sepiina are the families A) Belosaepiidae; B) Sepiadariidae; C) Sepiidae and D) Sepiolidae. 2) Under the Suborder Vasseuriina are the families: A) Vasseuriidae and B) Belosepiellidae
Species include common cuttlefish, giant cuttlefish, pharaoh cuttlefish, hooded, cuttlefish, Sepia latimanus, Metasepia pfefferi, Sepia mestus, Sepia bandensis, Sepia veranyi, Sepia vicellius, squid, Euprymna scolopes, Sepia esculenta, European squid, Sepiola atlantica, Idiosepius paradoxus, Euprymna berryi, Sepia aculeata, Sepioloidea pacifica, Sepia plangon, Euprymna tasmanica, Sepioloidea lineolata, Sepia elegans, Sepia rozella, Sepioloidea lineolata, Sepiadarium kochi, Sepiella inermis, Metasepia tullbergi, Sepia recurvirostra, Sepia prashadi, Sepia typica, Sepia lycidas, Sepioteuthis australis, Sepia foliopeza, Sepia vietnamica, Sepia appellofi, Sepia carinata, Sepia dollfusi, Sepia tenuipes, Sepia thurstoni, Sepia kobiensis, Sepia vossi, Sepia longipes, Sepia acuminata, Sepia adami, Sepia aureomaculata, Sepia baxteri, Sepia burnupi, Sepia chirotrema, Sepia confusa, Sepia cottoni,
Websites and Resources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Fishbase fishbase.se ; Encyclopedia of Life eol.org ; Smithsonian Oceans Portal ocean.si.edu/ocean-life-ecosystems
Pfeffer's flamboyant cuttlefish (Scientific name:Metasepia pfefferi) are found in tropical Indo-Pacific waters, especially along the coast of northern and western Australia and the southern coast of New Guinea. They are bottom-dwellers typically found at depths of three to 86 meters (10 to 282 feet) in sandy or muddy substrates in reefs, coastal areas and intertidal (littoral) zones on the shores.[Source: Chandni N. Patel and Michael J. Smith, Animal Diversity Web (ADW) /=]
Pfeffer’s flamboyant cuttlefish are small cephalopods that reach lengths of six centimeters (2.36 inches). They have a dark brown base color with overlaying patterns of white and yellow. Its arms are purple-pink. Their skin is chock-a-block with chromatophores — pigment cells — that can be manipulated to make color changes. Both sexes are roughly equal in size, look similar and have similar colors except when spawning. The lifespan of Pfeffer’s flamboyant cuttlefish is estimated to be between 18 and 24 months based on knowledge of other species in the same family. /=\
Pfeffer’s flamboyant cuttlefish is one of only three known venomous species of cephalopods. The venom is very toxic and it may possibly be able to kill an adult human quickly. The venom has been shown to have similar lethal effects as that of the blue-ringed octopus, Pfeffer’s flamboyant cuttlefish have not been evaluated for the International Union for Conservation of Nature (IUCN) Red List. They have no special status according to the Convention on the International Trade in Endangered Species (CITES).
Flamboyant Cuttlefish Characteristics and Behavior
Flamboyant cuttlefish Pfeffer’s flamboyant cuttlefish are venomous, cold blooded (ectothermic, use heat from the environment and adapt their behavior to regulate body temperature) and heterothermic (have a body temperature that fluctuates with the surrounding environment). They are diurnal (active mainly during the daytime) and motile (move around as opposed to being stationary). Cuttlefish feed primarily on crustaceans and bony fish. Their beak is used to capture prey. Cuttlefish are preyed upon by seals, dolphins, sharks and other fish. [Source: Chandni N. Patel and Michael J. Smith, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web: Pfeffer’s flamboyant cuttlefish has a very broad, oval mantle that is flattened dorsoventrally. The dorsal mantle has three pairs of large, flat, flap-like papillae, which cover its eyes. The dorsal anterior edge of the mantle lacks the tongue-like projection that is common among all other species of cuttlefish. The head is slightly narrower than the mantle. The mouth is surrounded by ten appendages. Two of the appendages are tentacles and eight of them are arms. The arms are broad and blade-like. On males, one of the arms is modified into a hectocotylus for holding and transferring spermatophores. The cuttlebone, the defining feature of a cuttlefish, is approximately two thirds to three quarters the length of the mantle.
Pfeffer’s flamboyant cuttlefish is a slow swimmer, relative to other cephalopods, such as squid. The internal cuttlebone is used to regulate buoyancy by controlling the gas and liquid that it lets into the chambers of the cuttlebone. Because the cuttlebone is small relative to the mantle, cuttlefish in general cannot swim very long and generally "walk" along the bottom. Pfeffer’s flamboyant cuttlefish has a highly developed set of eyes. During the day, it spend its time actively hunting for food. The chromatophores located on its skin allow them to easily change colors to blend in with their environment when stalking prey.
When Pfeffer’s flamboyant cuttlefish is threatened, it quickly change its colors through the manipulation of its chromatophores. It creates black, white and yellow patches on its dark brown skin and turns the tips of its arms bright red. These bright colors are used to warn other creatures of its venomous nature. It will keep this color pattern while waving its protective arm membranes, until it no longer feels threatened. Cuttlefish in general will secrete ink to disorient a predator and escape.
Flamboyant Cuttlefish Reproduction and Development
Pfeffer’s flamboyant cuttlefish are oviparous (young are hatched from eggs) and engage in internal reproduction in which sperm from the male parent fertilizes an egg from the female parent. They are polyandrous, with females mating with several males during one mating season. [Source: Chandni N. Patel and Michael J. Smith, Animal Diversity Web (ADW) /=]
Pfeffer’s flamboyant cuttlefish breed during a six to eight week period in the spring. Males put on colorful displays to attract females. Some males may change color to look like a female to avoid more aggressive males and discreetly gain access to females. After fertilization, the female lays her eggs one by one in hard to reach cracks and crevices to hide and keep them out of reach of predators. There is no parental care post after hatching and cuttlefish die not long after spawning. The eggs initially are round and white, and become clear as the egg develops. Development timing depends on water temperature.
Males have a specialized, hectocotyl arm that is used for holding and transferring spermatophores (packets of sperm) into the females buccal areas during mating. The female grabs the spermatophores with her arms and wipes them onto her eggs. Sometimes male cuttlefish spray water into the female's buccal area to clear out spermatophores from previous mates.
Common cuttlefish (Scientific name: Sepia officinalis) is generally found in the eastern North Atlantic, the English Channel, the Mediterranean Sea and the west coast of Africa, as far south as South Africa. Also known as the European cuttlefish, they are a typically found in coastal areas and on or near the sea bottoms from depths of 200 meters (656 feet) up to the surface. Described as a “shallow water cephalopod”, they favor sandy or muddy substrates and engage in seasonal migrations. They spend the autumn and winter at depths near 200 meters and migrate during the spring and summer to inshore waters, where they reside at depths of around 100 meters ot less. [Source: Ae Lin Compton and Laura Wiley, Animal Diversity Web (ADW) /=]
Common cuttlefish typically spend the daytime hidden in sand and hunt at night. They prey on a wide variety of animals — primarily crustaceans and fish, and occasionally nemertean worms, polychaetes, gastropods, and even other cuttlefish. These cuttlefish are ambush predator that often hunt by blending in with the background and sneaking as up close to prey as they can. When the prey is close, the cuttlefish have two methods of attack. One is to shoot out the two longer tentacles, grab the prey using the suckers on the tentacular clubs at the tips of the tentacles and bring the prey into the cuttlefish’s beak to feed. The other is pounce on prey, with the cuttlefish using its arms to capture and maneuver the prey while it tears at the prey with its radula and beak. Both adult and immature cuttlefish hunt for food during the night. Some studies have shown that cuttlefish embryos have the ability to learn about prey items while still encased in their eggs using their fully-developed eyes to observe prey species. Hatchlings that observed crabs while inside their eggs preferred to eat crab over other prey items. [Source: Ae Lin Compton and Laura Wiley, Animal Diversity Web (ADW) /=]
Common cuttlefish are highly active,, grows quickly, expend a lot energy reproducing and die young. Their lifespan is typically one to two years. The species believed to be abundant and populations are stable and healthy. Studies have indicated that fishing occurs around the maximum sustainable yield, Common cuttlefish have not been evaluated for the International Union for Conservation of Nature (IUCN) Red List. They have no special status according to the Convention on the International Trade in Endangered Species (CITES).
Common Cuttlefish Characteristics and Behavior
Common cuttlefish have an average weight of three kilograms (6.6 pounds) and an average mantle length of 45 centimeters (17.7 inches). Those living in the subtropics have an average mantle length of 30 centimeters (11.8 inches) and weight of two kilograms (4.4 pounds) whiles those in temperate areas have an average mantle length of 49 centimeters (19.3 inches) and a weight of four kilograms (8.8 pounds). The largest recorded individual reached a mantle length of 60 centimeters. Common cuttlefish are cold blooded (ectothermic, use heat from the environment and adapt their behavior to regulate body temperature) and heterothermic (have a body temperature that fluctuates with the surrounding environment). There is some sexual dimorphism (differences between males and females): Both sexes are roughly equal in size and look similar but sexes colored or patterned differently. [Source: Ae Lin Compton and Laura Wiley, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web: Common cuttlefish have large eyes and a mouth with beak like jaws located at the base of the mantle. The mantle houses reproductive and digestive organs, as well an internal shell called the cuttlebone. The cuttlebone shape is oblong with a rounded posterior end and an anterior end that tapers to a point. The body of the common cuttlefish is broad and dorso-ventrally flattened, having an oval shaped cross section. A pair of flat, wide fins runs the length of the mantle. The mouth is surrounded by eight arms and two longer tentacles, all equipped with suckers. Mature Common cuttlefish exhibit a zebra stripe pattern on the dorsal surface of their mantles during breeding season. Adult males are distinguished by white and black zebra bands on their fourth arm, as well as white arm spots. Common cuttlefish is able to change the color and even texture of its skin using structures called chromatophores, leucophores, and iridophores. These structures function to camouflage this species to its variable surroundings. Generally, however, Common cuttlefish has a mottled black or brown color. /=\
Common cuttlefish are nocturnal (active at night), motile (move around as opposed to being stationary), migratory (make seasonal movements between regions, such as between breeding and wintering grounds) and solitary. They typically roam between 90 to 550 meters in any one direction, which translates to a home range territory of between 5,300 and 23,700 square meters.
Common cuttlefish swims mainly to eat, mate or fight with other cuttlefish. The undulating fins on either side of its mantle aid in swimming. The European cuttlefish also has the ability to rapidly propel itself by forcing water through its siphon. Common cuttlefish is typically a solitary species except during mating. Cuttlefish can change the color and texture of its skin within seconds, allowing it to camouflage with its environment and to communicate with other cuttlefish or predators. Special structures within its skin enable it to change colors quickly. The cuttlefish expands and contracts these structures to create the different patterns of colors and textures on its skin. Common cuttlefish can create uniform body patterns or to exhibit multiple patterns at the same time. Another anti-predatory behavior is to secrete ink.
Common cuttlefish communicate with vision and sense using vision and touch. They have highly developed eyes and often communicates with other cuttlefish and predators using visual cues. Not only do they use their skin-changing ability to convey messages, they also communicates by swimming in certain patterns or holding their tentacles in certain postures. When threatened cuttlefish can eject ink from their siphons.
Common Cuttlefish Mating, Reproduction and Development
Common cuttlefish are oviparous (young are hatched from eggs) and semelparous (offspring are all produced in a single group), after which the parents usually die. They engage in seasonal breeding and internal reproduction in which sperm from the male parent fertilizes an egg from the female parent. Semelparous organisms usually only live through a single breeding season but sometimes live through several seasons. [Source: Ae Lin Compton and Laura Wiley, Animal Diversity Web (ADW) /=]
Common cuttlefish typically breed only once in their lifetime and the breeding season is during the spring and summer. The number of offspring ranges from 100 to 1000 and the gestation period ranges from 30 to 90 days. Females reach sexual maturity at 14 to 18 months. Males reach sexual maturity at 13 to 18 months. Fertilized eggs are stored in the oviduct of the female until they are ready to be deposited. Pre-fertilization provisioning and protecting is done by females. Eggs are produced with deposits of ink, to color and camouflage the them. Young hatch with a yolk to provide them with some food until they are able to catch their own prey. /=\
Common cuttlefish are polygynous (males having more than one female as a mate at one time). According to Animal Diversity Web: In the spring and summer, male and females migrate to shallow, warmer waters to spawn. They exhibit elaborate courtships, wherein males attract females through spectacular displays of colored bands passing rapidly along their bodies. Males then hold their arms stiffly in a basket formation to show their virility. Similarly, females display a uniform gray color when ready to mate. Mate guarding, in which males aggressively fight over and guard their females, is also common.
The male deposits spermaphores into the female’s buccal membrane using a hectocotylized arm (tentacle arm used as intromittent organ). Males carry as many as 1400 spermatophores, while females carry somewhere between 150 and 4000 eggs, depending on body size. Females can lay eggs several times at the ends of their lives. However, after spawning both male and females die.
Before the females dies she deposits clusters of eggs on seaweed, shells, and other substrate along the seafloor. Eggs measure six to nine millimeters in diameter. They typically hatch after about two months, with a range of 30 to 90 days, depending on water temperature. Once hatched, the young cuttlefish measure about five centimeters in length. Newly hatched young are well developed and can start feeding on small prey almost immediately. Growth rates vary with temperature, with young growing faster at lower temperatures. /=\
Broadclub cuttlefish (Scientific name: Sepia latimanus) are sometimes called reef cuttlefish. They can be found in Indian Ocean and western Pacific Ocean from the Andaman Sea west of India in the north to the northern coast of Australia in the south. They are fairly common in the Malacca Strait, the South and East China Seas, the Great Barrier Reef, the Coral Sea, and off the coast of Fiji. Broadclub cuttlefish are among the most important prey for bottlenose dolphins in some places. [Source: Hannah Markowitz, Animal Diversity Web (ADW) /=]
Broadclub cuttlefish reside in relatively shallow water at depths of 10 to 30 meters (33 to 98 feet). You can typically find them in reefs or other coastal areas in water temperatures ranging between 16° and 30°C (61° and 86°F). When spawning they swim closer to the shore to deposit their eggs in coral reefs. Broadclub cuttlefish often hide in the crevices of coral reefs in order to evade predators and watch for prey.
Broadclub cuttlefish weigh up to 10 kilograms (22.03 pounds). Females are larger than males. Sexes are colored or patterned differently with the male being more colorful. Male and female cuttlefish are differentiated by markings on the skin; males have irregular, transverse lines across their mantles, upper fins, and tentacles. Females do not have these lines, but they do have elongated ocelli, or eyespots, on their fins. Cuttlefish are usually measured in mantle length, excluding the length of their tentacles. Males have mantle lengths of around 17 centimeters (6.7 inches)while females have mantle lengths of around 24 centimeters (9.5 inches).
Broadclub cuttlefish have an oval-shaped mantle — the structure on the back side wall of their bodies — and narrow fins extending along the sides. They get their its name from the crescent shaped, club-like limbs situated on either side of their mantle, between their fins and tentacles. Broadclub cuttlefish display 13 body patterns. These patterns include six long-lasting ones that may endure for hours, even days, and seven that last for only seconds or minutes.
Broadclub Cuttlefish Behavior, Hunting and Reproduction
Broadclub cuttlefish differ from other cuttlefish species in that they spend their time in relatively shallow water. The maximum range they travel is 550 meters. During the breeding season, they move further inshore to deposit their eggs. They are most active during the daytime, when they swim around coral reefs looking for prey to catch. [Source: Hannah Markowitz, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web: Although many cephalopods, including broadclub cuttlefish, are thought to be solitary, a recent study done off the coast of Okinawa Island in Japan has suggested that they may travel in schools. Yasumuro et al. (2015) reported that groups of broadclub cuttlefish exhibited similar postures and patterns, although their colors varied when the colors of their surroundings varied. It was also observed that new broadclub cuttlefish joining the group would acclimate to the group, eventually exhibiting the same body patters. It was reported that these cuttlefish fish would all swim in the same direction, equidistant from one another. They may do this for protection against predators or to find potential mates. /=\
Broadclub cuttlefish hunt prey using their changing body patterns to mesmerize and confuse prey. They can also change colors to blend in with their surroundings and sneak up on prey or lay in wait and ambush it. Broadclub cuttlefish are known for preying specifically on shrimp and prawns of the genus Palaemon, but they can be opportunistic feeders too. They typically hunt for small prey along the bottom of the ocean by ejecting water to flush prey from their hiding places in the sand. /=\
The breeding season for broadclub cuttlefish is January through May in may places. The number of offspring ranges from 10 to 30. The gestation period ranges from 38 to 44 days, with the average gestation period being 40 days. Females reach sexual maturity at 10 to 16 months with an average of around 12 months. Males reach sexual maturity at 12 to 18 months, with an average or around 16 months. Broadclub cuttlefish have little involvement with their offspring after females deposit eggs. See Cuttlefish Mating and Reproduction [Source: Hannah Markowitz, Animal Diversity Web (ADW) /=]
They reach lengths of four feet and generally live two or three years. Males usually die after mating season. [Source: Fred Baverendam, National Geographic, September 1995]
Australia Giant Cuttlefish
Australian giant cuttlefish (Scientific name: Sepia apama) get their common name where they makes their home. They are found almost exclusively in the waters off of southern Australia, residing, in coastal waters and bays extending from Ningaloo and Pointes Cloates in Western Australia, across Australia’s southern coast, and northward along the eastern coast to Shoalwater Bay in Queensland, and including Tasmania. Outside of Australian waters, the cuttlefish can also be found around some east Indian Ocean and southwest Pacific Ocean islands. [Source: Dianne Aglibot, Animal Diversity Web (ADW) /=] They are native to the Pacific Ocean and Indian Ocean. /=\
Australian giant cuttlefish inhabits coral reefs, seagrass meadows, rocky reefs, kelp forests and muddy and sandy areas at depths less than a 100 meters (328 feet). As a rule cuttlefish tend to live in shallow seas where sunlight is abundant and plankton production is high. The porous nature of their cuttlebone, which helps keep them buoyant, also prevents them from going too deep.
Australian giant cuttlefish are terminal spawners. That means they become sexually mature at about one year of age and breed and die shortly afterwards. The main economic utilization of Australian giant cuttlefish is as food and bait and cuttlebones for pet birds. They are caught incidentally as by-catch in trawl fisheries, and on a small-scale using jigs, hooks, and spears. Their spawning aggregations in Spencer Gulf, South Australia attract hundreds of divers, scientists, and ecotourists to view this spectacular event. [Source: Dianne Aglibot, Animal Diversity Web (ADW) /=]
Australian giant cuttlefish are listed as "near threatened" on the International Union for Conservation of Nature (IUCN) Red List: Near Threatened; They have no special status according to the Convention on the International Trade in Endangered Species (CITES). Intense fishing in a few areas have sharply decreased their populations there. Places where Australian giant cuttlefish aggregates to spawn annually such as northern Spencer Gulf, have been under management protection since 1998 and closed to fishing.
Australia Giant Cuttlefish Characteristics and Behavior
Australian giant cuttlefish weigh up to 10.5 kilograms (23 pounds) and reach lengths of around 50 centimeters (19.7 inches). Both sexes are roughly equal in size and look similar. They are diurnal (active during the daytime), nocturnal (active at night), crepuscular (active at dawn and dusk), motile (move around as opposed to being stationary) and solitary. They have no territory or home range, sense using vision, touch, vibrations and chemicals usually detected with smell and communicate with vision, touch and mimicry. [Source: Dianne Aglibot, Animal Diversity Web (ADW) /=]
According to Animal Diversity Web: Australian giant cuttlefish has a bulky body, with 10 appendages (8 short, heavy arms, and two larger extensible tentacles), highly developed eyes, and a reddish-brown skin with white spots on the arms and mantle. Along each side of the body, a long, pale lateral fin extends the length of the mantle; these fins are used in maneuvering. Cephalopods’ bodies are streamlined, making them efficient at swimming. In addition to their swimming abilities, they have the ability to change colors by the means of contracting or expanding pigments in special cells called chromatophores, located in the skin.
Many aspects of the giant cuttlefish’s behavior can be observed through its dynamic ability in changing colors and patterns. While Australian giant cuttlefish is generally solitary, they interact with conspecifics during mating season, when males attract females by flashing their chromatophores. Though cuttlefishes are colorblind, they can camouflage themselves in total darkness within seconds. This instantaneous skill is possible by blending simple colors in order to form a great variety of hues in conjunction with a layer of cells called leucophores, which reflect white light. The leucophores allow cuttlefishes to blend in with their environment by precisely matching the ambient light level and color without the animal even needing to use their eyes to detect the color environment around it. This species may display an innate curiosity towards scuba divers.
Radiotracking studies of this species reveal that individuals spend more than 95 percent of the day resting, which suggests that they do not actively forage for food, but instead are lie-and-wait predators. Individuals do not seem to migrate daily or seasonally, except to return to their spawning grounds. Radiotracking studies revealed that one individual moved 65 kilometers to return to the spawning aggregation in Spencer Gulf.
Australian giant cuttlefish is usually a solitary animal, but they communicate with other cuttlefishes during mating season. Even though a giant Australian cuttlefish has highly developed eyes, individuals are color blind. However, they communicate by contracting the chromatophores in their skin. Their perception of their surroundings is unmatchable due to the chromatophores and leucophores in their skin. /=\
Australia Giant Cuttlefish Mating, Reproduction and Development
Australia giant cuttlefish are oviparous (young are hatched from eggs) and engage in internal reproduction in which sperm from the male parent fertilizes an egg from the female parent. The breeding season is during several months of the Australian winter. The gestation period ranges from three to five months.The number of offspring ranges from 100 to 300. On average females and males reach sexual maturity at age one year. After the egg capsules have been laid, the female cuttlefish abandons them and dies. [Source: Dianne Aglibot, Animal Diversity Web (ADW) /=]
Reproduction in the giant cuttlefish is promiscuous, characterized by large spawning aggregations, multiple mating and paternities, potential sperm competition, and female choice. Males elaborately use their color changing abilities to attract female males by flashing their chromatophores. Less dominant males disguise themselves by assuming female coloration and can "hide" among females until they find an opportunity to mate when the dominant males are distracted (the "sneaker male" reproductive phenomenon)./=\
During the mating season, giant cuttlefish males battle with one another over choice dens. When two males encounter one another they puff up and stretch out their bodies to look as threatening as possible. Most confrontations end with the weaker cuttlefish slinking away after a ritual combat but occasionally fights take place in which losers — and winners — have arms bitten off. [Source: Fred Baverendam, National Geographic, September 1995]
When a females come around the males retreat to their dens and wave their arms and changes colors in an effort to attract the female. Sometimes while the male is driving off a rival male a “transvestite” male, impersonating a female, shows up and tries to a passes his sperm to the female.
After the female chooses a suitor the mating itself doesn't take long. The male uses one of its arms to place a sperm capsule into a pouch beneath the female’s mouth. The capsules break open, spreading sperm into her mantles and fertilizing her eggs. The female then swims into his den as deep as possible to lay her eggs and swims away, abandoning her young and dying soon afterwards. A female may mate several times with multiple males during a spawning aggregation..
The eggs, which are lined with gas chambers to create neutral buoyancy, hang like stalactites on the top of the den. After four months young giant cuttlefish break through the translucent shell and immediately have to fend for themselves in a world full of predators. Young cuttlefish have a natural instinct to hide under rock and in kelp beds. The development of Australian giant cuttlefish is characterized by two alternative life cycles for both females and males: one featuring rapid juvenile growth and requiring only seven to eight months to reach maturity during the first summer; and a second one featuring slower juvenile growth during the summer, with the cuttlefish reaches maturity during the second year of life.
Image Sources: Wikimedia Commons, NOAA
Text Sources: Animal Diversity Web (ADW) animaldiversity.org; National Oceanic and Atmospheric Administration (NOAA) noaa.gov; Wikipedia, National Geographic, Live Science, BBC, Smithsonian, New York Times, Washington Post, Los Angeles Times, The New Yorker, Reuters, Associated Press, Lonely Planet Guides and various books and other publications.
Last Updated April 2023