Eastern Grey Squirrel

Eastern Grey Squirrel (Sciurus carolinensis)

By Jasper Tapen    Nov/13/2014

Introduction

Many of the different names are given to the eastern grey squirrel, such as Bannertail and Silvertail grey squirrel depending on region, Latin name Sciurus carolinensis comes from two Greek words, skia, meaning shadow, and oura, meaning tail.

Description

The head and body length is from 23 to 30 cm (9.1 to 11.8 in), the tail from 19 to 25 cm (7.5 to 9.8 in) and the adult weight varies between 400 and 600 g (14 and 21 oz.).  Eastern gray squirrel commonly occurs in two colors, grey and black Gray individuals are predominantly gray, but it can have a brownish color with white underside. Black individuals are generally a glossy uniform black. Genetic variations within grey squirrels include individuals with black tails and black-colored squirrels with white tails,  or reddish color phase and some animals may also have a combination of colors for example a black body with a red tail. Albino eastern grey squirrels also occur and also completely white populations are found.

The most prominent physical feature of the eastern grey squirrel is its large bushy tail which it uses for balance, as a warm covering during the winter months and perhaps as a sunshade in summer. Tail can be used to distract pursuing predators. It acts as a shock absorber when the animal jumps from high places.

Distribution

Sciurus carolinensis is native to the eastern and Midwestern United States, and portions of the eastern Canada. The eastern gray squirrel in Canada is found from New Brunswick to Manitoba, in USA from East Texas to Florida,

In Europe is a concern because they have displaced some of the native squirrels prolific and adaptable species, they out-compete the native reds for food, feeding more at ground level and being able to digest acorns, which the reds can’t. European Union has expressed concern it will similarly displace the red squirrel from parts of the European continent.

The eastern gray squirrel has been introduced to Ireland, Italy, South Africa and Australia.

Diet

Eastern gray squirrels eat a wide range of foods, such as tree bark, tree buds, berries, many types of seeds and nuts (acorns, hickory nuts, walnuts, beechnuts and pecans), some types of fungi found in the forests, including fly agaric mushrooms (Amanita muscaria). They can cause damage by tearing the tree bark and eating the soft cambial tissue underneath. In Europe, sycamore (Acer pseudoplatanus) L. and beech (Fagus sylvatica L.) suffer the greatest damage.

Eastern gray squirrels have a high enough tolerance for humans to inhabit residential neighborhoods and will raid bird feeders for millet, corn, and sunflower seeds. They will also raid gardens for tomatoes, corn, strawberries, and other garden crops. On very rare occasions, when their usual food sources are scarce, eastern gray squirrels will also prey upon insects (adults and larvae), frogs, small rodents including other squirrels, and small birds, their eggs and young. They will also gnaw on bones, antlers, and turtle shells – likely as a source of minerals sparse in their normal diet.

Behavior

Squirrels are tree-dwelling rodents they are agile climbers and jumpers with keen senses of sight, smell, and hearing and are alert, nervous and wary, especially on the ground. They live in urban areas and in woodland areas. Eastern gray squirrels prefer constructing their dens upon large tree branches and within the hollow trunks of trees. They also have been known to take shelter within abandoned bird nests in urban areas squirrels build a type of nest, known as a “drey”, in the forks of trees, consisting mainly of dry leaves and twigs. Males and females may share the same nest for short times during the breeding season and during cold winter spells squirrels may share a drey to stay warm. They may also nest in the attic or exterior walls of a house.

Grey Squirrel is mostly active during daylight, although it can sometimes be seen feeding by the light of a full moon. In summer, activity is greatest early in the morning and in mid-afternoon. Unlike a lot of other squirrels, eastern grey squirrels do not hibernate and in winter are most active around midday taking advantage of the warmest temperatures.

Reproduction:

Eastern gray squirrels can breed twice a year, but younger and less experienced mothers will normally have a single litter per year in the spring. Depending on abundance of food, older and more experienced females may breed again in summer. In a year of abundant mast crop 36% of females will bear two litters, but none will do so in a year of poor mast crop. Their breeding seasons are December to February and May to June, though this is slightly delayed in more northern latitudes. The first litter is born in February or March, the second in June or July. Birthing may be advanced or delayed by a few weeks depending on climate, temperature and forage availability. In any given breeding season an average of 61 – 66% of females will bear young. If a female fails to conceive or loses her young to unusually cold weather or predation, she will re-enter estrus and have a later litter. Normally, one to four young are born in each litter, but the largest possible litter size is eight. The gestation period is about 44 days. The young are weaned at around 10 weeks, though some may wean up to six weeks later in the wild. They begin to leave the nest after 12 weeks, with autumn born young often wintering with their mother. Only one in four squirrel kits will survive to one year of age, with mortality of around 55% for the following year. Mortality rates then decrease to around 30% for following years until they increase sharply at eight years of age.

A litter of gray squirrels may contain both black and grey individuals and all shades between black, grey and red.

Eastern gray females can rarely enter estrus as early as five and a half months old, but females are not normally fertile before at least one year of age. Male Eastern Greys are sexually mature between one and two years of age. These squirrels can live to be 20 years old in captivity, but in the wild live much shorter lives due to predation pollution and the challenges of their habitat.

Predation

Predators include humans, hawks, weasels, raccoons, foxes, domestic and feral cats, snakes, owls, coyotes, wolves and dogs. In its introduced range in South Africa it has been preyed on by African harrier-hawks.

Gray squirrels were eaten in earlier times by Native Americans and their meat is still popular with hunters across most of their range in North America. Today, it is still available for human consumption and is occasionally sold in the United Kingdom

Unique Adaptetions

The eastern gray squirrel is one of very few mammalian species that can descend a tree head-first. It does this by turning its feet so the claws of its hind paws are backward pointing and can grip the tree bark.

Squirrels can lose its tail sheath and some bones to escape a predator’s grasp they can run reaching speeds of up to 25 km per hour on the ground.

Animal Ambassadors International

© Copyright 2014 JP TP ARTS All Rights Reserved

Keystone Species

Keystone Species

By Jasper Tapen    Nov/10/2014

Definition of keystone species: described as species that is playing a unique and critical role in maintaining the structure and balance of an ecosystem, if a keystone species is removed ecosystem may experience a dramatic shift even though that species was a small part of the ecosystem by measures of biomass or productivity. Just like keystone in an arch’s crown, keystone species play the same role in many ecological communities by maintaining the structural integrity of the community. Since the prey numbers are low, the keystone predator numbers can be even lower and still be effective. Yet without the predators, the herbivorous prey would explode in numbers, wipe out the dominant plants, and dramatically alter the character of the ecosystem. The exact scenario changes in each example, but the central idea remains that through a chain of interactions, a non-abundant species has an out-sized impact on ecosystem functions. Keystone species theory remains a young theory and the underlying concepts and is still in developing stages. It takes a great deal of study for scientists to understand the complexities and nuances of ecosystems and their keystone species, and there is still much work to be done.

History

Robert T. Paine, a professor of zoology at the University of Washington, proposed the keystone species concept, using Pisaster ochraceus, a species of starfish, and Mytilus californianus, a species of mussel as a primary example. In his 1966 paper, Food Web Complexity and Species Diversity, Paine described such a system in Makah Bay in Washington, Professor Paine follow-up in his 1969 paper where he introduced the term keystone species. Keystone species play important role in keeping out new plants or animals that could come into the habitat and push out the native species.

Keystone species concept originally referred specifically to a predator. However, other species can play the same role by definition of Power et al. implies that keystone species can exert their influence through other interactions as well for example ecosystem engineers, pollinators and mutualist. Other example, diseases that have strong impacts on their hosts would also be classic examples of keystone species under the broad definition of Power et al., since the disease organisms generally have a very small biomass in the system. For example, an outbreak of rinderpest in the late 19th century in southern Africa had a catastrophic impact on ungulates, and their loss cascaded to cause a fundamental transition in the African landscape, from grassland to woody savannah. Sugar maple good example of plant as keystone species, this tree is a keystone species of the hardwood forest. It brings water from lower levels in the ground that helps other plants. It is also home to many insects, birds, and small animals.

                                                                     Predators

In most cases is a small predator that prevents a particular herbivorous species from eliminating dominant plant species. Declines of relatively rare top predators like wolf and cougars in terrestrial ecosystems have allowed populations of herbivores such as white-tailed deer to explode, with devastating impacts on the biomass and species composition of terrestrial vegetation. Keystone predators don’t need to be apex predators (Sea stars are prey for sharks, rays, and sea anemones. Sea otters are prey for orca.) A Classic Keystone Species is Sea Otters they are keystone species in the kelp forests. They eat many invertebrates, but especially sea urchins. If there are too many sea urchins, they will eat too much of the kelp and destroy it.

                                                                      Mutualists

Keystone mutualists are organisms that participate in mutually beneficial interactions, for example, there is a period of each year when Banksia prionotes (Acorn Banksia) is the sole source of nectar for honeyeaters, which play an important role in pollination of numerous plant species. Therefore the loss of this one species of tree would probably cause the honeyeater population to collapse, with profound implications for the entire ecosystem. Another example is frugivores such as the cassowary, which spreads the seeds of many different trees, and some will not grow unless they have been through a cassowary.

Pollinators

The critical importance of pollination has been recognized since humans first gave up nomadic lifestyles. Bees are considered keystone species, by pollinating plants, bees contribute to their survival. The plants are shelter for insects, which are then eaten by other species, like birds. Pollination is the reason hummingbirds are a keystone species. In places where the numbers of hummingbirds are low, other species of plants will take over the ecosystem.

   Engineers

Prairie dog is one of keystone species they make burrows and provide nesting areas for Mountain Plovers and Burrowing Owls. Prairie dog tunnel systems also help channel rainwater into the water table to prevent runoff and erosion, and can also serve to change the composition of the soil in a region by increasing aeration and reversing soil compaction that can be a result of cattle grazing. Prairie dogs also trim the vegetation around their colonies, perhaps to remove any cover for predators. Another well-known ecosystem engineer and keystone species is the beaver, which transforms its territory from a stream to a pond or swamp. Beavers affect the environment first altering the edges of riparian areas by cutting down older trees to use for their dams. This allows younger trees to take their place. Beaver dams alter the riparian area they are established in. Depending on topography, soils, and many factors, these dams change the riparian edges of streams and rivers into wetlands, meadows, or riverine forests. These dams have shown to be beneficial to myriad species including amphibians, salmon, and song birds.

Conservation efforts tend to focus on the preservation of keystone species to stabilize the entire biological community, as the loss or decline of a keystone species within an ecosystem has serious consequences for the continued productivity, structure and function of the ecosystem.

                                                          Things to think about…….

According to noted biologist E.O. Wilson, we are now seeing species extinctions at 1,000 times the normal rate, and there is no disagreement among biodiversity scientists that this is human-caused. How many of these lost species will turn out to have been keystone species?

How much habitat change can our natural world withstand before a domino effect causes truly disastrous results?

References and Recommended Reading

-Outland, K. Who’s afraid of the big bad wolf? The Yellowstone wolves controversy. Journal of Young Investigators 11, (2010).

– Beck, S. & Meier, T. Managing wolf depredation in the United States: past, present, and future. Sheep and Goat Research Journal 19, 41–46 (2004).

-Duggins, D. O. Kelp beds and sea otters: an experimental approach. Ecology 61, 447–453 (1980).

-Paine, R.T. (1995). “A Conversation on Refining the Concept of Keystone Species”. Conservation Biology

Take Home Message: Understanding nature will help you understand yourself.

Animal Ambassadors International

© Copyright 2014 JP TP ARTS, All Rights Reserved

Black squirrel

Black squirrel

The black squirrel is a melanistic subgroup of the eastern gray squirrel. Melanism is a development of the dark-colored pigment melanin in the skin or its appendages and is the opposite of albinism. Historically, it was also the medical term for black jaundice. The word melanism is deduced from the Greek: μελανός, meaning “black pigment”.

There are also pure white and pure black squirrels but both are variations of the gray squirrel.”  Biologists surmise that the black fur more readily absorbs the rays of the sun, thereby keeping its owner warmer during cold winters. Selective genetics has given the black squirrel this survival advantage.

As a melanistic variety of the eastern gray squirrel, individual black squirrels can exist wherever grey squirrels live. Grey mating pairs cannot produce black offspring. Gray squirrels have two copies of a normal pigment gene and black squirrels have either one or two copies of a mutant pigment gene. If a black squirrel has two copies of the mutant gene it will be jet black. If it has one copy of a mutant gene and one normal gene it will be brown-black. In areas with high concentrations of black squirrels, mixed litters are common. The black subgroup seems to have been predominant throughout North America prior to the arrival of Europeans in the 16th century, as its dark color helped them hide in old growth forests which tended to be very dense and shaded. As time passed, hunting and deforestation led to biological advantages for grey coloured individuals. Today, the black subgroup is particularly abundant in the northern part of the eastern gray squirrel’s range. This is likely due to the significantly increased cold tolerance of black squirrels which lose less heat than greys. Black squirrels also enjoy concealment advantages in denser northern forests.

Distribution

Large natural populations of black squirrels can be found throughout Ontario and in several parts of Ohio, Maryland, Michigan, Indiana, Virginia, Washington, D.C., Wisconsin, Minnesota, and Pennsylvania. Populations of grey squirrels in which the black subgroup is predominant can be found in these six areas as well as in smaller enclaves in Missouri, New Jersey, Delaware, southern New York, Illinois and Connecticut

Large increase in our rodent population makes us a prime hangout for Eagles, Red-tailed Falcons and the like, as well as the Wiley Fox and other fleet of foot predetators which keeps natures balance in the proper order.

Photo;

JP TP ARTS Studio by Jasper

Attenborough’s long-beaked echidna (Zaglossus attenboroughi)

Looks Aren’t Everything

Attenborough’s long-beaked echidna (Zaglossus attenboroughi)

This animal is one of three species from the genus Zaglossus to occur in New Guinea. It is named in honor of Sir David Attenborough. It was considered extinct until recent expeditions have discovered tracks and locals have reported seeing the creature.

Status:

Given the ongoing anthropogenic disturbance of the Cyclops Mountain forest habitat, this has raised concern that Z. attenboroughi populations may already be endangered or even locally extirpated. However, biological surveys of Papua province are notoriously incomplete; it is possible that the animal still exists there or in related mountain ranges.

The echidna is endangered by hunting and habitat loss. In fact, in the 1900s, it was thought to be extinct until some of their “nose pokes” were found in the mountains of New Guinea. These “nose pokes” are very distinct and represent the echidna’s feeding techniques. This animal is so high in the endangered-species list that locals are being educated on this creature and asked to stop their tradition of hunting and killing it and sharing it with rivals as a peace offering. As reported on July 15, 2007, researchers from EDGE visiting Papua’s Cyclops Mountains had recently discovered burrows and tracks thought to be those of Zaglossus attenboroughi. Furthermore, communication with local people revealed that the species had perhaps been seen as recently as 2005. In 2007, Sir David’s long-beaked echidna was identified as one of the top-10 “focal species” by the Evolutionarily Distinct and Globally Endangered (EDGE) project.

Conservation Proposed:

Attenborough’s long-beaked echidna was believed extinct until EDGE team members uncovered evidence of its continued survival in 2007. The species is likely to be highly threatened and in need of urgent conservation action, which should include working with local communities to raise awareness of the species and enforcing the protection of the Cyclops Mountains Strict Nature Reserve. Further research into the species’ ecology and threats such as hunting pressure, coupled with regular monitoring will help to inform future conservation actions.

Additional research measures include carrying out surveys in areas of suitable habitat in the Foja Range and comparative genetic analysis of all currently recognized long-beaked echidna taxa in order to better understand the evolutionary status and conservation significance of the Cyclops Mountains long-beaked echidna population.

Description:

The species was described from a single damaged specimen collected in the Dutch colonial era (c. 1961), and has apparently not been collected since then

It weighs from 5 to 10 kilograms (11 to 22 lb). It is the smallest member of the genus, being closer in size to the short-beaked echidna than are the other members of the genus. The male is larger than the female, and can be differentiated by the spurs on its hind legs. Found in tropical montane moss forest. Its altitudinal range is approximately 166 to 1,600 m.

Behavior:

Not much is known about the ecology of this species, since its behaviour has never been recorded.

The creature is nocturnal, and can roll up into a spiny ball when it feels threatened, somewhat in the manner of a hedgehog. The echidna is not a social animal, and comes together with its own kind only once a year, in July, to mate. The female will lay the eggs after about eight days, and the babies will stay in the mother’s pouch for around eight weeks or until their spines develop.

Photo credit:

Photo 1

Long-beakedEchidna.jpg ‎(391 × 299 pixels, file size: 50 KB, MIME type: image/jpeg)

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.

Photo 2

Sources:

: http://news.nationalgeographic.com/news/2007/07/070718-echidna.html

http://www.edgeofexistence.org/mammals/species_info.php?id=2

Bongo antelope Boocercus eurycerus

Bongo antelope  Boocercus eurycerus facts

The bongo is known for its graceful, spiraled horns and beautiful striped hide. Timid, well camouflaged, and mostly nocturnal, it is one of Africa’s most mysterious animals. The largest of all forest antelopes, bongos measure up to four feet at the shoulder.

Distribution:

Bongos are found in tropical jungles with dense undergrowth up to an altitude of 4,000 meters (12,800 ft) in Central Africa, with isolated populations in Kenya, and these West African countries: Angola, Benin, Burkina Faso, Cameroon, the Central African Republic, the Republic of the Congo, the Democratic Republic of Congo, the Ivory Coast, Equatorial Guinea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Mali, Niger, Sierra Leone, South Sudan, Togo, and Uganda.

Description:

Bongos are one of the largest of the forest antelopes. In addition to the deep chestnut colour of their coats, they have bright white stripes on their sides to help with camouflage. Adults of both sexes are similar in size. Adult height is about 1.1 to 1.3 m (3.6 to 4.3 ft) at the shoulder and length is 2.15 to 3.15 m (7.1 to 10.3 ft), including a tail of 45–65 cm (18–26 in). Females weigh around 150–235 kg (331–518 lb), while males weigh about 220–405 kg (485–893 lb). Its large size puts it as the third-largest in the Bovidae tribe of Strepsicerotini, behind both the common and greater elands by about 300 kg (660 lb), and above the greater kudu by about 40 kg (88 lb). The pigmentation in the coat rubs off quite easily; anecdotal reports suggest rain running off a bongo may be tinted red with pigment. The smooth coat is marked with 10–15 vertical white-yellow stripes, spread along the back from the base of the neck to the rump. The number of stripes on each side is rarely the same. It also has a short, bristly, and vertical brown ridge of hair along the spine from the shoulder to the rump; the white stripes run into this ridge.

A white chevron appears between the eyes, and two large white spots grace each cheek. Another white chevron occurs where the neck meets the chest. The large ears are to sharpen hearing, and the distinctive coloration may help bongos identify one another in their dark forest habitats. Bongos have no special secretion glands, so rely less on scent to find one another than do other similar antelopes. The lips of a bongo are white, topped with a black muzzle.

Lifestyle

The Bongo is a shy and elusive creature that is seldom seen by people due to it’s highly nocturnal lifestyle. As with many other antelope species, Bongos turn and flee almost immediately when they feel threatened and can disappear quickly into the surrounding forest, running with their horns laid back against their body to prevent them from getting tangled up in the vegetation. Male Bongos are solitary and will only come into contact with other Bongos to breed, whereas although females can be found on their own, they often form herds that can contain up to 50 members and consist of the females and their young (for protection). Bongos produce a variety of different calls so they are able to communicate including grunts, snorts, moos and bleating to warn others of approaching danger or when they are in distress. In many areas throughout their natural range, Bongos have been hunted by people for meat but also became a prize target for big-game trophy hunters which devastated local populations. The biggest impact that people have had on the Bongo though is the fact that vast areas of their natural habitats have disappeared to make room for agriculture and to provide grazing for livestock. This increasing closeness to Humans has led to outbreaks of disease in Bongos, along with severe population declines due to their dwindling habitats and therefore, an increasing lack of both food and suitable forest cover which Bongos heavily rely on.

Status:

The eastern bongo is arguably one of the most threatened large mammals in Africa, with recent estimates numbering less than 140 animals, below a minimum sustainable viable population. The situation is exacerbated because these animals are spread across four isolated populations. Whilst the bongo endangered species program can be viewed as having been successful in ensuring survival of this species in Europe, it has not yet become actively involved in the conservation of this species in the wild in a coordinated fashion. The plan is to engage in conservation activities in Kenya to assist in reversing the decline of the eastern bongo populations and genetic diversity in Africa, and in particular, applying population management expertise to help ensure the persistence of genetic diversity in the free ranging wild populations. To illustrate significance of genetic diversity loss, assume the average metapopulation size is 35 animals based on 140 animals spread across four populations (140/4=35). Assuming stable populations, these populations will lose 8% of their genetic diversity every decade. By managing all four populations as one, through strategic transfers, gene loss is reduced from 8% to 2% per decade, without any increase in bongo numbers in Kenya. By managing the European and African populations as one – by strategic exports from Europe combined with in situ transfers, gene loss is reduced to 0.72% every 100 years, with both populations remaining stable. If populations in Kenya are allowed to grow through the implementation of effective conservation, including strategic transfers, gene loss can be effectively halted in this species and its future secured in the wild.

In 2002, the IUCN, listed the western/lowland species as Near Threatened. These bongos may be endangered due to human environmental interaction, as well as hunting and illegal actions towards wildlife. CITES lists bongos as an Appendix III species, only regulating their exportation from a single country, Ghana. It is not protected by the US Endangered Species Act and is not listed by the USFWS. The IUCN Antelope Specialist Group considers the western or lowland bongo, T. e. eurycerus, to be Lower Risk (Near Threatened), and the eastern or mountain bongo, T. e. isaaci, of Kenya, to be Critically Endangered. Other subspecific names have been used, but their validity has not been tested.

Sources:

Photo credit :

Photo by Greg Hume P-1 Photo by Bodlina P-2

http://en.wikipedia.org/wiki/File:TragelaphusBongo.jpg

Frilled Shark (Chlamydoselachus anguineus)

Highly unusual and less known life forms but not less important.

Frilled Shark (Chlamydoselachus anguineus)

Conservation status: Near Threatened by the IUCN Red List. Although little is known of its life history, this deep water species is likely to have very little resilience to depletion as a result of even non-targeted exploitation.

Scientific classification

Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Subclass: Elasmobranchii

Order: Hexanchiformes

Family: Chlamydoselachidae

Genus: Chlamydoselachus

Species: C. anguineus

Introduction:

The frilled shark was first scientifically recognized by German ichthyologist Ludwig Döderlein, who visited Japan between 1879 and 1881 and brought two specimens to Vienna. However, his manuscript describing the species was lost, and so the first description of the frill shark became authored by American zoologist Samuel Garman, working from a 1.5 m (4.9 ft) long female caught from Sagami Bay in Japan. His account, entitled “An Extraordinary Shark”, was published in an 1884 volume of Proceedings of the Essex Institute. Garman placed the new species in its own genus and family, and gave it the name Chlamydoselachus anguineus from the Greek chlamy (“frill”) and selachus (“shark”), and the Latin anguineus for “snake-like”. Other common names for this species include frill shark, lizard shark, scaffold shark, and silk shark.

More recent investigations have found that the similarities between the frilled shark and extinct groups may have been overstated or misinterpreted, and that this shark exhibits a number of skeletal and muscular traits that firmly place it with the neoselachians (modern sharks and rays), and more specifically with the cow sharks in the order Hexanchiformes (though systematist Shigeru Shirai has proposed that it be placed in its own order, Chlamydoselachiformes). Nevertheless, the frilled shark belongs to one of the oldest still-extant shark lineages, dating back to at least the Late Cretaceous (c. 95 Ma) and possibly to the Late Jurassic (c. 150 Ma). Because of its ancient ancestry and “primitive” characteristics, it has been described as a “living fossil”.

Distribution and habitat:

The frilled shark inhabits the outer continental shelf and upper to middle continental slope, seeming to favor upwellings and other biologically productive areas. Though it has been caught from a depth of 1,570 m (5,150 ft), it usually does not occur deeper than 1,000 m (3,300 ft). In Suruga Bay, it is most common at a depth of 50–200 m (160–660 ft), except from August to November when the temperature at the 100 m (330 ft) water layer exceeds 15 °C (59 °F) and the sharks shift into deeper water. On rare occasions, this species has been seen at the surface. The frilled shark is usually found close to the bottom, with one individual observed swimming over an area of small sand dunes. However, its diet suggests that it does make substantial forays upward into open water. This species may make vertical migrations, approaching the surface at night to feed. There is spatial segregation by size and reproductive condition. Rather uncommon, the frilled shark has been recorded from a number of widely scattered locations in the Atlantic and Pacific Oceans. In the eastern Atlantic, it occurs off northern Norway, northern Scotland and western Ireland, from France to Morocco including Madeira, and off Mauritania. In the central Atlantic, it has been caught at several locations along the Mid-Atlantic Ridge, from north of the Azores to the Rio Grande Rise off southern Brazil, as well as over the Vavilov Ridge off West Africa. In the western Atlantic, it has been reported from off New England, Georgia, and Suriname. In the western Pacific, it is known from southeastern Honshu, Japan, to Taiwan, off New South Wales and Tasmania in Australia, and around New Zealand. In the central and eastern Pacific, it has been found off Hawaii, California, and northern Chile. The frilled sharks off southern Africa were described as a different species, C. africana, in 2009.

Description:

Their mouth is located at the leading edge of their snout (terminal) rather than underneath like most sharks and they have small tricuspid teeth in both jaws. Their rows of teeth are rather widely spaced, numbering 19–28 teeth in their upper jaws and 21–29 teeth in their lower jaws. Each tooth is small, with three slender, needle-like cusps alternating with two cusplets. Their very long jaws are positioned terminally (at the end of the snout), as opposed to the underslung jaws of most sharks. They have a small lobe-like dorsal finexternal link set far back over their pelvic fins with an anal fin that is larger than their dorsal fin. Their pectoral fins are small and paddle-shaped and their very long caudal fin (tail fin) has a small ventral lobe and without a subterminal notch. Many frilled sharks are found with the tips of their tails missing, probably from predatory attacks by other shark species.

Highly specialized for life in the deep sea, the frilled shark has a reduced, poorly calcified skeleton and an enormous liver filled with low-density lipids, allowing it to maintain its position in the water column with little effort. Owing to its deep water habitat, very few observations of the frilled shark have been made in its natural environment . Analysis of stomach contents of frilled sharks brought to the surface indicate that this species mostly preys on deep water squid and a variety of fish, including other sharks

Sources:

http://marinebio.org/

http://en.wikipedia.org/wiki/File:Chlamydoselachus_anguineus_head.jpg

http://www.arkive.org/

Photo credit:

Photo1 The mouth of a frilled shark (Chlamydoselachus anguineus) at Shin-Enoshima Aquarium. This image was originally posted to Flickr by saname777 at http://flickr.com/photos/27730398@N08/3429890893. It was reviewed on 14 April 2009 by the FlickreviewR robot and was confirmed to be licensed under the terms of the cc-by-2.0.

Photo2 http://www.google.ca/imgres?imgurl=http%3A%2F%2F2.bp.blogspot.com%2F-IlfZp0gkze4%2FTqzy9oe_SjI%2FAAAAAAAABTs%2FOM5rnd635m4%2Fs1600%2FFrilled%252BShark5.jpg&imgrefurl=http%3A%2F%2Flife-sea.blogspot.com%2F2011%2F10%2Flife-of-frilled-shark.html&h=500&w=500&tbnid=gSe47MEB5OgdIM%3A&zoom=1&docid=eOr9Ox9SwL9bPM&ei=tn5RVLaoJ4ieyQTZw4KwDw&tbm=isch&ved=0CCMQMygGMAY&iact=rc&uact=3&dur=409&page=1

Photo3 https://www.google.ca/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fdandeetv.wordpress.com%2F2014%2F09%2F07%2Fwonderful-creatures-1-frilled-shark-chlamydoselachus-anguineus%2F&ei=qIBRVOrcGo-kyASBxYKICg&bvm=bv.78597519,d.aWw&psig=AFQjCNGdbVMIf4J3i3IvR7mtJ_rI6v7MHA&ust=1414713399336372

Horse Equus caballus facts

Horse   Equus caballus facts

A Brief History of Horses

By 55 million years ago, the first members of the horse family, the dog-sized Hyracotherium, were scampering through the forests that covered North America. For more than half their history, most horses remained small, forest browsers. But changing climate conditions allowed grasslands to expand, and about 20 million years ago, many new species rapidly evolved. Some–but not all–became larger and had the familiar hooves and grazing diets that we associate with horses today. Only these species survived to the present, but in the past, small and large species lived side by side. The last prehistoric North American horses died out between 13,000 and 11,000 years ago, at the end of the Pleistocene, but by then Equus had spread to Asia, Europe, and Africa.

Humans domesticated horses some 6,000 years ago, and over time, we have created more than 200 breeds

There is only one species of domestic horse, but around 400 different breeds that specialize in everything from pulling wagons to racing. Feral horses are the descendents of once-tame animals that have run free for generations. Groups of such horses can be found in many places around the world. Free-roaming North American mustangs, for example, are the descendents of horses brought by Europeans more than 400 years ago. Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and, occasionally, beyond.  The oldest verifiable record was “Old Billy”, a 19th-century horse that lived to the age of 62.

• The only surviving branch of the horse family is the genus Equus, which includes zebras, asses, and donkeys along with the horse.
• Horses can sleep both lying down and standing up.
• Horses have bigger eyes than any other mammal that lives on land.
• The English-speaking world measures the height of horses in hands, abbreviated “h” or “hh”; one hand is equivalent to 4 inches. Horses are measured at the highest point of an animal’s withers (at the base of the neck). A horse described as 15.2 hh tall is 15 hands, 2 inches (62 inches).
• A horse can rest and even doze while standing by locking one of its hind legs at the stifle joint (basically, the knee). A group of ligaments and tendons called the stay apparatus holds the leg in place with minimal muscle involvement. Horses will switch from leg to leg to prevent fatigue in the locked leg.
• The Przewalski’s horse is the only truly wild horse species still in existence. The only wild population is in Mongolia.
• Horses use a range of different vocalisations to communicate. Whinnying and neighing sounds are elicited when horses meet or leave each other. Stallions (adult male horses) perform loud roars as mating calls, and all horses will use snorts to alert others of potential danger. Mares (adult female horses) use deep smooth sounds, whickering, when they are nursing a foal (infant horse).
• Horses are undeniably clever animals. Beyond being proficient at relatively simple learning tasks, they are also recognised as having the capacity to solve advanced cognitive challenges involving categorisation learning and a degree of concept formation.
• Equine assisted therapy is a growing field where horses help people with a wide range of mental health issues. A relationship between the patient and the horse develops and allows the person to engage with nature through a beautiful and peaceful animal. This aids in building trust, respect, compassion, communication and self-confidence. The skills learned through building a meaningful relationship with the horse are transferable to other aspects of the individual’s life.

Sources:

http://www.nationalgeographic.com/

http://www.amnh.org/

http://www.livescience.com/

The Rottweiler

The Rottweiler

“Rottweiler breeders aim at a dog of abundant strength, black coated with clearly defined rich tan markings, whose powerful appearance does not lack nobility and which is exceptionally well suited to being a companion, service and working dog.” This breed is all about balance, endurance, proportionality, intelligence and strength. The standards in place for the Rottweiler’s physical appearance by the American Kennel Club mimic these characteristics.

In 1931 the Rottweiler was officially recognized by the American Kennel Club, In 1936, Rottweiler were exhibited in Britain at Crufts, in 1966, a separate register was opened for the breed. In fact, in the mid-1990s, the popularity of the Rottweiler reached an all-time high with it being the most registered dog by the American Kennel Club. In 2013, the American Kennel Club ranked the Rottweiler as the 9th most popular purebreed in the United States.

According to the FCI Standard, the Rottweiler is good-natured, placid in basic disposition, very devoted, obedient, biddable and eager to work. Their appearance is natural and rustic, their behaviour self-assured, steady and fearless. They react to their surroundings with great alertness.

The American Kennel Club says it is: a calm, confident and courageous dog with a self-assured aloofness that does not lend itself to immediate and indiscriminate friendships. A Rottweiler is self-confident and responds quietly and with a wait-and-see attitude to influences in its environment. It has an inherent desire to protect home and family, and is an intelligent dog of extreme hardness and adaptability with a strong willingness to work, making them especially suited as a companion, guardian and general all-purpose dog.

Rottweilers are a relatively healthy, disease-free breed. As with most large breeds, hip dysplasia can be a problem. For this reason the various Rottweiler breed clubs have had x-ray testing regimes in place for many years. Osteochondritis dissecans, a condition affecting the shoulder joints, can also be a problem due to the breed’s rapid growth rate. A reputable breeder will have the hips and elbows of all breeding stock x-rayed and read by a recognised specialist, and will have paperwork to prove it.

They will also have certificates that their breeding animals do not have entropion or ectropion and that they have full and complete dentition with a scissor bite.

As with any breed, hereditary conditions occur in some lines. The Rottweiler is very prone to cancer which is among the most common causes of early death in Rottweilers. For unknown reasons, Rottweilers are more susceptible than other breeds to become infected with parvovirus, a highly contagious and deadly disease of puppies and young dogs. Parvovirus can be easily prevented by following a veterinarian’s recommended vaccine protocol.

The Rottweiler is one of the oldest of herding breeds is a descendant of ancient Roman drover dogs, a mastiff-type dog that was a dependable, rugged dog with great intelligence and guarding instincts. During their quest to conquer Europe, the Roman legion traveled in large numbers across the continent. The non-existence of refrigeration meant the soldiers had to bring herds of cattle with them on their excursions for food. These drover dogs were not only used to keep the herds of cattle together, but to guard the supply stock at night. Around 74 A.D. the Roman army travelled across the Alps and into the southern part of modern day Germany. For the next two centuries the Roman drover dogs were continually utilized in herding and driving cattle for trade even after the Romans were driven out of the area.

Rhino Poaching News

http://www.nationalgeographic.com/

U.S. Indictment Accuses South African Brothers of Trafficking Rhino Horns

Safari outfitters allegedly duped hunters into paying extra to illegally shoot rhinos.

By Laurel Neme  for National Geographic  PUBLISHED OCTOBER 23, 2014

U.S. authorities today announced the indictment of the alleged kingpin of a South African rhino poaching and trafficking syndicate, Dawie Groenewald, and his brother, Janneman, and their company Out of Africa Adventurous Safaris on multiple charges, including conspiracy, money laundering, and wildlife crime. The Groenewald brothers own and operate Out of Africa Adventurous Safaris, an outfitter that organizes and conducts trips in private hunting areas in Botswana, Tanzania, Zimbabwe, and South Africa, including at their 10,600-acre (4,300-hectare) game farm, Prachtig, about 40 miles (60 kilometers) south of the town of Musina, in South Africa’s Limpopo Province. U.S. authorities will be seeking to extradite the brothers from South Africa.

According to the 18-count indictment, between 2005 and 2010 the Groenewald brothers duped nine American hunters at their ranch into illegally shooting rhinos.

The brothers would then cut off the horns and sell them on the black market in Asia.

The Groenewalds and their safari company solicited American hunters at large regional sportsmen’s shows, including Safari Club International conventions.  They also donated hunts to local chapters of Safari Club International in Kansas City, Missouri, and a National Rifle Association convention in Louisville, Kentucky. They later offered hunters add-ons, such as the chance to shoot rhinos for additional fees (typically around $10,000). The outfitters said those rhinos were “problem” animals that were “dangerous” and “aggressive” and could be hunted legally. (Related: “Q&A: Can Airlifting Rhinos Out of South Africa Save the Species?”)

The Groenewalds said that although the hunters couldn’t export a rhino’s horn as a trophy, they could measure it and take photographs and videos of the hunt and of themselves posed with the dead animal, which could then be submitted to record books.   The Groenewalds and Out of Africa also offered Americans the chance to conduct “green” hunts, when the hunter would shoot a rhinoceros with a tranquilizer gun and then pose for photographs with the sedated animal.

The Groenewalds, however, never obtained the necessary permits, and they also concealed the fact that the hunts would be in violation of South African law. After photos were taken, the Groenewalds or their staff would cut off the horns with chainsaws or knives and sell the horns in Asia.

In essence, they earned profit twice: once for the sale of the hunt and again when they trafficked the horns.

Long Reach of U.S. Law

“These defendants tricked, lied, and defrauded American citizens in order to profit from these illegal rhinoceros hunts,” stated George Beck, Jr., U.S. Attorney for the Middle District of Alabama.

“Not only did they break South African laws, but they laundered their ill-gotten gains through our banks here in Alabama. We will not allow United States citizens to be used as a tool to destroy a species that is virtually harmless to people or other animals.”

The Groenewalds and Out of Africa are being charged under several U.S. laws, including the Lacey Act. The Lacey Act is a powerful legal tool that makes it a crime to knowingly sell in interstate and foreign commerce wildlife that was taken, possessed, transported, or sold in violation of foreign law. In this case, it refers to selling animal hunts that violated South African law. (Related: “For Rangers on the Front Lines of Anti-Poaching Wars, Daily Trauma.”)

“This case is intended to send a message to outfitters and professional hunters: The long reach of U.S. law will catch up to you if you involve our country and our hunters in criminal enterprises abroad,” says Jean Williams, Deputy Assistant Attorney General at the U.S. Justice Department’s Environment and Natural Resources Division. “If you sell your illegal hunts here, you are subject to prosecution here, regardless of where the hunt takes place.

“This case is also a cautionary tale for American hunters. As a consumer market, we have a special obligation to make sure that we are following the rules designed to protect both U.S. and foreign wildlife.”

Cooperation From South Africa

During the investigation into this illegal hunting scheme, U.S. authorities received substantial cooperation from South Africa’s National Prosecuting Authority and the specialized endangered species unit within the organized crime unit of the South African Police Service, known as the Hawks.”The fact that defendants used American hunters to execute this scheme is appalling—but not as appalling as the brutal tactics they employed to kill 11 critically endangered wild rhinos,” said U.S. Fish and Wildlife Service Director Dan Ashe.

“South Africa has worked extraordinarily hard to protect its wild rhino population, using trophy hunts as a key management tool. The illegal hunts perpetrated by these criminals undermine that work and the reputation of responsible hunters everywhere.”

Groenewald Charged in South Africa

Dawie Groenewald is the head of a rhino poaching and trafficking syndicate known in South Africa as the “Groenewald Gang” or “Musina Mafia.” He was arrested in 2010 along with ten others, including his wife, veterinarians, and professional hunters. (Neither Janneman Groenewald nor Out of Africa Adventurous Safaris was included.)

The South African indictment is 637 pages long and charges the group with 1,872 counts of illegal hunting, dealing in rhino horns, racketeering, money laundering, and fraud. (Related: “1,000+ Rhinos Poached in 2013: Highest in Modern History.”)

According to the book Killing for Profit, by Julien Rademeyer, Dawie Groenewald alone faces 1,736 counts that stem from his allegedly having illegally sold at least 384 rhino horns over a four-year period, having killed more than 39 of his own rhinos for their horns, and illegally dehorning more than 80 others.

That case has dragged on for almost four years, with trials postponed several times. The most recent, set for July 2014, was postponed to August 4, 2015, to allow conclusion of a civil suit regarding the constitutionality of current regulations for endangered and protected species.

The Groenewald group allegedly made about $6.8 million from the illegal sale of rhino horn.

According to the affidavit submitted by South Africa Police Service Colonel Johan Jooste, Dawie Groenewald managed the syndicate from 2006 to September 2010 while the others helped in pseudo-hunts, translocating and dehorning rhinos, making false applications for permits, and selling the horn. (Related: “Why African Rhinos Are Facing a Crisis.”)

Groenewald Interviewed

In an interview detailed in Killing for Profit, Dawie Groenewald expressed confidence that he will beat the South African case.

“They [the South African prosecutors] will eventually come and say there has been a mistake on a permit here, or something wrong there, let’s sort it all out. Let’s make arrangements for a fine. “I am not a poacher,” he told Rademeyer. “That word makes me sick. It is not necessary for me to poach a rhino.  “I don’t enjoy killing rhinos,” he continued. “But I’m killing them because of the system. We are forced to shoot them because that is the only way the trophies can be sold and exported. You have to kill the animal to sell its horns.” He went on to tell Rademeyer that he makes a lot of money from hunting, saying, “For me, to do these hunts is very good money. It is really good money.”

Operation Crash

The U.S. indictment is part of Operation Crash, an ongoing multiagency effort to detect, deter, and prosecute those engaged in the illegal killing of rhinos and the trafficking of their horns. The operation is led by the Special Investigations Unit of the U.S. Fish and Wildlife Service Office of Law Enforcement, in coordination with the U.S. Department of Justice. Operation Crash takes its name from the term “crash,” which describes a herd of rhinos.

So far, there have been 26 arrests and 18 convictions, with prison terms as long as 70 months. The indictments against the Groenewalds and their company are the first of Operation Crash that involve the direct killing of wild rhinos. Those convicted include Zhifei Li, the “boss” of three antique dealers who obtained and smuggled rhino horn out of the U.S. into China on his behalf; Qiang “Jeffrey” Wang, who smuggled Asian artifacts, including “libation cups” made from rhinoceros horn and ivory; and Michael Slattery, Jr., an Irish national who illegally trafficked rhino horn throughout the United States, and is alleged to belong to an organized criminal group engaged in rhino horn trafficking.

As of October 14, 868 rhinos had been poached this year in South Africa alone.

Yet the numbers are really far worse. Cases like the ones against Dawie and Janneman Groenewald and Out of Africa Adventurous Safaris are not included in those figures.

“What we’re seeing here is added to those awful statistics,” Williams noted. “It’s even larger than what’s documented.” In sentencing Zhifei Li in New Jersey, U.S. District Judge Esther Salas reflected on the seriousness of rhino horn trafficking charges. “The reality is there is a need to send a message to society, to those that deal in this market, this black market, that if you are apprehended, whether you are smuggling old rhinoceros horns, horns for black rhinoceros, or some white tusks from elephants, if you are doing this, and you are internationally exporting these materials, you are going to face severe and swift punishment.”

http://www.nationalgeographic.com/

Blue crab facts

Blue crab

The Chesapeake blue crab or Atlantic blue crab, Callinectes sapidus

The blue swimmer crab, Portunus pelagicus

The blue king crab, Paralithodes platypus

The Japanese blue crab, Portunus trituberculatus

The blue crab is so named because of its sapphire-tinted claws. Its shell, or carapace, is actually a mottled brownish color, and mature females have red highlights on the tips of their pincers. Prized by humans for their sweet, tender meat, these wide-ranging, ten-legged crustaceans are among the most heavily harvested creatures on the planet. Their scientific name, Callinectes sapidus, means “savory beautiful swimmer.”

Blue crabs are found in brackish coastal lagoons and estuaries from Nova Scotia, through the Gulf of Mexico, and as far south as Uruguay. Close relatives of the shrimp and lobster, these bottom-dwelling omnivores have a prickly disposition and are quick to use their sharp front pincers. Large males can reach 9 inches (23 centimeters) in shell width.

They feed on almost anything they can get hold of, including mussels, snails, fish, plants, and even carrion and smaller blue crabs. They are also excellent swimmers, with specially adapted hind appendages shaped like paddles.

Atlantic blue crab  (Callinectes sapidus)

Atlantic blue crab, or the Chesapeake blue crab, is a species of crab native to the waters of the western Atlantic Ocean and the Gulf of Mexico, and introduced internationally.  Callinectes sapidus may grow to a carapace width of 230 mm (9.1 in). It can be distinguished from a related species occurring in the same area by the number of frontal teeth on the carapace; C. sapidus has four, while C. ornatus has six

After showing signs of a big comeback, the Chesapeake Bay’s blue crab population has plunged by more than half. The results of a winter survey, released Friday, showed that crab numbers fell 61 percent, from an estimated 765 million last year to 300 million crabs in 2013 — the lowest number in five years.

Virginia and Maryland have been working hard to bring crabs back, and largely succeeding, since the population nearly crashed in 2007, prompting a federal disaster declaration. Officials called the latest findings disappointing, but they emphasized that crab numbers fluctuate a lot naturally.

Crabs responded quickly. The population jumped from an estimated 251 million in 2007 to last year’s 765 million — the highest total since the early 1990s.

Conservation efforts

Unique expertise and facilities for broodstock, hatchery and juvenile production of blue crabs. ARC is a 1,800-square-meter, state-of-the-art, environmentally responsible marine core facility that operates on recirculating artificial seawater. The Gulf Coast Marine Life Center will implement and build upon their infrastructure and technologies to successfully mass-produce blue crab juveniles for stock enhancement efforts along the Gulf coast region. The University of Maryland (ARC) has published abundant amount of information on the effective stock enhancement, including releasing large batches of individually tagged juvenile hatchery crab and monitoring them through DNA fingerprinting as well as developing optimal release strategies. Studies leading to a better understanding of the Blue Crab biology and life cycle are helping wildlife officials develop new policies for managing this economically vital fishery.

University of Maryland Institute of Marine and Environmental Technology’s Aquaculture Research Center (ARC

The blue swimmer crab, Portunus pelagicus

Portunus pelagicus, also known as the flower crab, blue crab, blue swimmer crab, blue manna crab or sand crab, and alimasag in Tagalog, is a large crab found in the intertidal estuaries of the Indian and Pacific Oceans (Asian coasts) and the Middle-Eastern coast of the Mediterranean Sea. The name “flower crab” is used in east Asian countries while the latter names are used in Australia. The crabs are widely distributed in eastern Africa, Southeast Asia, East Asia, Australia, Persian Gulf and New Zealand. The males are bright blue in colour with white spots and with characteristically long chelipeds, while the females have a duller green/brown, with a more rounded carapace. The carapace can be up to 20 centimetres (7.9 in) wide.

They stay buried under sand or mud most of the time, particularly during the daytime and winter, which may explain their high tolerance to ammonium (NH4+) and ammonia (NH3). They come out to feed during high tide on various organisms such as bivalves, fish and, to a lesser extent, macroalgae. They are excellent swimmers, largely due to a pair of flattened legs that resemble paddles. However, in contrast to another portunid crab (Scylla serrata), they cannot survive for long periods out of the water.

1. pelagicus commonly enters estuaries for food and shelter. Its life cycle is dependent on estuaries as the larvae and early juveniles use these habitats for growth and development. Prior to hatching, the female moves into shallow marine habitats, releases her eggs and the newly hatched zoea I larvae move into estuaries. During this time they feed on microscopic plankton and progress from the zoea I stage to the zoea IV stage (approximately 8 days) and then to the final larval stage of megalopa (duration of 4–6 days). This larval stage is characterised by having large chelipeds used to catch prey. Once the megalopa metamorphoses to the crab stage they continue to spend time in estuaries which provides a suitable habitat for shelter and food. However, evidence has shown that early juveniles cannot tolerate low salinities for extended periods, which is likely due to its weak hyper-osmoregulatory abilities. This may explain their mass emigration from estuaries to seawater during the rainy season. Male Portunus pelagicus are believed to become more territorial in colder water. This may explain why male crabs are rarely sighted within a close proximity to each other in more temperate waters; it also may explain why their female counterparts seem more prolific in these such areas.

The blue king crab  Paralithodes platypus

Species of king crab which lives near St. Matthew Island, the Pribilof Islands, and the Diomede Islands, Alaska, with further populations along the coasts of Japan and Russia. Blue king crabs from the Pribilof Islands are the largest of all the king crabs, sometimes exceeding 18 pounds (8.2 kg) in weight.

Commercial blue king crab harvest around the eastern Bering Sea began in the mid-1960s and peaked in 1981 with a catch of 13,228,000 pounds (6,000 t). The Pribilof Island harvest by the United States peaked in 1980 at 10,935,000 lb (4,960 t) and was closed in 1988 due to population decline, then again in 1999 after being opened for three years. The St. Matthew fishery peaked in 1983 with 9,453,500 lb (4,288.0 t) but experienced a similar decline and was closed in 1999. It was opened in 2009, and was featured on the television show Deadliest Catch. The St. Matthew stock is rebuilding but the fishery remains closed, while the Pribilof stock has not drastically improved.  Diomede blue king crabs have never been harvested commercially, but support a subsistence fishery for the Native Village of Diomede, Alaska, population 170.

Colder water slows the rate of crab growth and crabs at northern latitudes are often smaller than more southern crabs. Commercial harvest of blue king crabs at the Pribilof Islands is limited to males with a carapace width (CW) over 6.5 inches (170 mm) and St. Matthew Island is limited to crabs with CW greater than 5.5 in (140 mm), corresponding to crabs over 4.7 in (120 mm) carapace length (CL). Diomede blue king crabs are similar in size to St. Matthew Island crabs.

Pribilof Island blue king crabs mate and produce eggs in late March to early May. Females generally brood their eggs externally for 12–14 months. Since blue king crabs need more than a year to brood their eggs, they miss a breeding cycle just before the larvae hatch and only produce eggs every other year, although first-time breeders can often produce eggs in subsequent years. Females release larvae around the middle of April in the Pribilof Islands, while those held at warmer temperatures in the laboratory may release larvae as early as February.

Female blue king crabs in the Pribilof Islands grow to the largest size before they are reproductively mature. About 50% of crabs are mature at 5 in (130 mm) CL. St. Matthew Island females can become sexually mature at 3 in (76 mm) CL and Diomede crabs are similar. Larger female crabs from the Pribilof Islands have the highest fecundity, producing 162,360 eggs or 110,033 larvae per crab. The reduction in fecundity is about 33% between the egg and larval stages. In Japan, an average of 120,000 larvae were released from each blue king crab. Diomede blue king crabs release an average of 60,000 larvae per female.

Environmental variables, such as tides, temperature, salinity, light, phytoplankton blooms, and predation, are seasonally pulsed and likely serve as cues for larval release. Release of larvae over a longer period may serve to give the female a larger window for larvae to correspond with any favorable environmental conditions that may exist, also known as “bet-hedging”. In the laboratory, Pribilof larvae hatch over the course of about one month, and Diomede larvae hatch over the course of 2–3 weeks. These differences may be due to water temperature in the laboratory, which has a clear effect on embryonic and larval development, and is probably slightly different from hatch timing in a natural environment.

The Japanese blue crab, Portunus trituberculatus

Portunus trituberculatus, the gazami crab, Japanese blue crab or horse crab, is the most widely fished species of crab in the world. It is found off the coasts of East Asia and is closely related to Portunus pelagicus.

The carapace may reach 15 centimetres (5.9 in) wide, and 7 cm (2.8 in) from front to back. P. trituberculatus may be distinguished from the closely related (and also widely fished) P. pelagicus by the number of broad teeth on the front of the carapace (3 in P. trituberculatus, 4 in P. pelagicus) and on the inner margin of the merus (4 in P. trituberculatus, 3 in P. pelagicus).  Carapace rough to granulose with regions discernible.  Front with 3 acutely triangular teeth with the central projected slightly forwards of the lateral ones; 9 teeeth on each anterolateral margin, the most external one much larger than the preceding.  Chelipeds elongate: larger chelae with conical tooth at the base of fingers; 4 spines on the inner margin of the merus. Legs laterally flattened to variyng degrees, last 2 segments of last pair paddle-like.  Carapace colour dull green to brown.

1. trituberculatus is the world’s most heavily fished crab species, with over 300,000 tonnes being caught annually, 98% of it off the coast of China.

Sources

http://www.nationalgeographic.com/

http://www.gcmlc.com/index.php

http://www.fao.org/fi/website/FIRetrieveAction.do?dom=topic&fid=3380&lang=en

Photo credit

http://en.wikipedia.org/wiki/