Portunus belongs to the family Portunidae that are recognized from whatever remains of the round-fronted (cyclometope) crabs by the adjustment of a portion of their legs for swimming, to which end these appendages are changed into smoothed oars.

The outcome is regularly to give upon the crabs an intensity of dashing at fast through the water, which would barely be credited by the individuals who have not watched them.

Comparing to this portability they have a thin leveled type of body, empowering them to go sideways through the water, and a softness picked up to the detriment of the defensive fingernail skin.

source: www.crabdatabase.info

These characteristics give the swimming crabs a strikingly unique real frame from the vigorously assembled, moderate moving Xanthids, or, in other words by a similarly stamped distinction of living space.


NameSwimming Crab
Scientific NamePortunus
SynonymPortunus pelagicus,
Portunus denticulatus

Vernacular names

English: blue swimming crab

Chinese: 远海梭子蟹

Japanese: タイワンガザミ

Thai: ปูม้า


The family is exceedingly factor and varietal and is likely experiencing fast advancement in numerous ways.


Portunus is a variety of crab which incorporates a few imperative animal types for fisheries, for example, the blue swimming crab, Portunus pelagicus and the Gazami crab, P. trituberculatus.

The males are brilliant blue in shading with white spots and with naturally long chelipeds, while the females have a blunter green/dark colored, with a more adjusted carapace. The carapace can be up to 20 centimeters (7.9 in) wide.

Fossil Records

The three-spotted crab (P. sanguinolentus) are gotten as bycatch. The variety Portunus contains in excess of 90 surviving species and more than 40 encourage species known just from fossils.

Fossils of crabs inside this sort can be found in the residue of Europe, the United States, Mexico, Venezuela, Brazil and Australia from Paleogene to later (age extend: 48.6 to 0.0 million years ago).

Distinctive Features of Portunus

Distinctive features of portunus are as follows:


The collections of most Portunidae are decorated or ensured with sharp thistles or teeth, and it is on such characters as the number and size of these and the state of the lobed front that the species are by and large recognized.

However much of the time enough isn’t known about their propensities to make it conceivable to state whether, and if so how, these are useful to the creatures.


P. pelagicus usually enters estuaries for nourishment and asylum. Its life cycle is reliant on estuaries as the hatchlings and early adolescents utilize these natural surroundings for development and advancement.

Before incubating, the female moves into shallow marine natural surroundings discharges her eggs and the recently brought forth zoea I hatchlings move into estuaries. Amid this time they feed on minuscule microscopic fish.

source: www.crabdatabase.info

Also, advancement from the zoea, I stage to the zoea IV organize (roughly 8 days) and after that to the last larval phase of megalopa (term of 4– 6 days). This larval stage is portrayed by having huge chelipeds used to get prey.

Once the megalopa transforms to the crab organize they keep on investing energy in estuaries which gives an appropriate environment to safe house and sustenance.

Proof has demonstrated that early adolescents can’t endure low salinities for broadened periods, or, in other words to its frail hyper-osmoregulatory abilities. This may clarify their mass migration from estuaries to seawater amid the blustery season.

Male Portunus is accepted to wind up more regional in colder water. This may clarify why male crabs are once in a while located inside a closeness to one another in more mild waters. It also may clarify why their female partners appear to be more productive in these such zones.


The Xanthids are as a rule to be found on the reef or shore presented to the full power of the breakers. In this position, the daintily assembled swimming crabs would be dashed to pieces against the stones.

Their legitimate frequent is a space of calm waters, for example, the tidal pond of a coral atoll, and as these spots seem to be, in the tropics, by and large, bottomed with white or grayish coral sand, on which the crabs lie.

Also, in which they regularly shroud their bodies, they every now and again impersonate it by their pale grayish shading, regularly in a way as striking as that in which level fish look like the shingly base they live on.

source: www.flickr.com

In the meantime, the swimming crabs are in no way, shape or form completely limited to a base of coral sand even in the tropics. In profound water, where rocks are not related to peril.

They are found on each sort of base in about equivalent numbers, and here, on the off chance that they conceal, it must be under stones. They even happen, however not all that all the time, on the reef.

In any case, the crabs found in this position may perhaps have strayed from the tidal pond with the cordial tide. Most likely, when more is thought about the lives of the species.

It will be discovered that sure of them keep up their reality on the reef by protecting under stones or in squares of coral, where if anyplace they are constantly found and that others-unquestionably the heft of crabs leans toward the tidal pond.

In their propensities these crabs are dynamic and shrewd, getting away catch with shrewdness. The tidal pond frames, as a rule, hold near the sand and don’t rise in excess of a couple of feet into the water, however, others swim as intensely and emphatically as fish.

Food Habitat

Portunus eat both meat and plants, thus they are omnivores.

Behavior of Portunus

They remain covered under sand or mud more often than not, especially amid the daytime and winter, which may disclose their high resilience to ammonium (NH4+) and smelling salts (NH3).

They turn out to nourish amid high tide on different life forms, for example, bivalves, angle and, to a lesser degree, macroalgae. They are astounding swimmers, to a great extent because of a couple of straightened legs that take after oars.

In any case, rather than another portunid crab (Scylla serrata), they can’t get by for significant lots out of the water.

Lifespan of Portunus

The average lifespan of a portunus is 3 to 4 years.

Health Benefits

The species is monetarily critical all through the Indo-Pacific where they might be sold as conventional hard shells, or as “delicate shelled” crabs, which are viewed as a delicacy all through Asia.

The species is profoundly prized as the meat is nearly as sweet as Callinectes sapidus. These species look intensely and solely for meat utilization in the Persian Gulf with the females sold at higher costs than guys.

These qualities, alongside their quick development, the simplicity of larviculture, high fruitfulness and generally high resistance to both nitrate and ammonia, (especially ammoniacal nitrogen, NH3– N).

In other words lethal than ammonium, as it can all the more effectively diffuse over the gill layer), makes this species perfect for aquaculture.

Similar Species

The species that are similar to Portunus are:

Portunus armatus

Portunus brockii

Portunus pelagicus

Portunus sanguinolentus

Portunus sayi

Portunus trituberculatus

Fun Facts of Portunus

Following are the fun facts of portunus:

fun facts

Apart from being fun, they are hazardous as well.



  1. www.animaldiversity.org
  2. www.eol.org
  3. www.en.wikipedia.org
  4. www.awesomeocean.com

Amna Shaheen

I have done Bachelors in Computer Software Engineering from Foundation University in 2017. Now, I am doing MS in Project Management and I am a blogger at TapeDaily. I am very passionate about plants and animals. I like to study about them, so I write blogs that are related to plants and animals.

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