Diversity of crab in Jammu waters

Meenakshi Bandral
Crab copyAs the word ‘crab’ comes to our mind the creatures are visualized crawling on stones or rocks in coastal area near sea-beaches. Such crab are classified as marine crab.
For people of J&K, presence of crab in its water bodies is a matter of great surprise. Since our state hosts fresh water ecosystems experiencing tropical and subtropical climate, therefore, along with fishes and prawns, crab though in less quantum are also available. These crab belong to the families Potamidae and Paratelphusidae, are nutritively rich with protein content of 54.38% . Fresh water crab along with fishes and prawns offer an alternate source of food thus fulfilling local protein demand.
Regarding the diversity of fresh water crab in our State, a survey carried out in water bodies of plains and hilly areas, confirm their presence in a number of waterbodies viz Gho-manhasan, Sehi, Sarore, Gadigarh, Ban Ganga, Jajjharkotli, Poonch, Chenani and Sunderbani. In Mansar and Surinsar lake, it is reported to be absent.
Survey carried out in Kashmir valley (Dal Lake, Harwan, Dachigam stream) gave negative results since not even a single specimen appeared while netting.
From the areas scanned so far, two species of freshwater crab have been reported viz Maydelliathelphusa masoniana (Henderson 1893) and Himalayapotamon emphysetum (Alcock 1909).
The former species viz Maydelliathelphusa masoniana recorded from the water bodies of plain areas viz Gho- Manhasan, Sehi, Sarore, Gadigarh is a taxonomic revision of earlier reported species Paratelphusa masoniana from Gadigarh (Dutta, 1978) and Gho Manhasan  (Gupta, 2012) stream of Jammu region. Morphologically this species exhibit dark chocolate brown/black colour with shiny carapace, reaching upto maximum carapace width of 7cm. They exhibit sexual dimorphism with bigger sized males than females. The chelas used for grasping and eating are robust with cutting edges or teeth.
Later species newly identified as Himalayapotmon emphysetum (Alcock 1909) is available in the water bodies of hilly areas viz. Ban Ganga, Jajjarkotli, Sunderbani, Poonch and Chenani of Jammu region.
Morphologically this species exhibit beautiful reddish brown/orange colouration crab population with maximum carapace width of 5cm. They also exhibit sexual dimorphism with lesser size variations in males than females. The chelas used for grasping are medium sized, less serrated but have a peculiar feature of purple or blue colouration at their tips.
Thus, the two species of crab reported from the fresh water bodies of our state being contrast in their location or distribution and morphological features indicate towards the probability of presence of other species too. Rigorous survey is being carried to authenticate and update the data on crabs diversity of our state.
(The author is (Asstt Prof) University of Jammu, Jammu)

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