Biodiversity of hermit crabs in Odisha, east coast and their distribution in other coastal states of India

Hermit crabs are one among the least studied group of the animal kingdom. The diversity of hermit crabs of entire Odisha coast was studied for the first time. Collected primary data and secondary data were compiled to prepare an updated checklist of hermit crabs of Indian coast. A total of seven species of hermit crabs were recorded during the field surveys along Odisha coast. The compilation of secondary data with present primary data revealed occurrence of 114 species of hermit crabs belonging to 27 genera and six families along the Indian coast. Diogenidae was identified as the dominant family. The diversity of hermit crabs is high in the west coast (73 species) as compared to the east coast (65 species). Maximum species diversity is recorded in Tamil Nadu (53 species), Kerala (50 species) and in Andaman & Nicobar Islands (46 species). Twenty threes species of hermit crabs inhabit the coastal ecosystems of Odisha. The present study also reports the occurrence of Clibanarius infraspinatus for the first time from Odisha thus, extending its distributional range along the Indian coast. Among the reported 114 species, only 61 species are included in GBIF with Indian distribution whereas occurrence data is not available for 11 species and 42 species are not likely distributed along Indian coast. The findings of the present study support the occurrence of 61 species (included in Global Biodiversity Information Facility) along the Indian coast and suggest that the occurrence and distribution of remaining 53 species can be confirmed after conducting extensive field surveys

Growth, mortality and stock assessment of Arius arius (Hamilton, 1822) from Hooghly-Matlah estuary, West Bengal

The growth, mortality, and stock assessment of Arius arius were estimated based on monthly length-frequency analysis data collected from the Hooghly-Matlah estuary of West Bengal, India from April 2017 to March 2018. The estimated growth parameters were as L∞ = 278 mm, K = 0.97 yr-1, and t0 = -0.0889 years. The different mortality coefficients Z, M, and F were obtained as 5.25 yr-1, 1.79 yr-1, and 3.46 yr-1, respectively. The calculated exploitation ratio (E) was found as 0.66, and the M/K value as 1.845 indicating overexploitation of the fish. The recruitment was found throughout the year with two peaks and the value of Lc was found at 56.00 mm. The estimated virtual population analysis (VPA) indicated that the highest fishing mortality (F) of 3.4499 was observed at the 190-200 mm length class, followed by 3.2393 from the 180-190 mm length class. The fishery was found at the overexploitation level and measures are needed to regulate it for promoting its sustainability