Antibiotic resistance has been one of the most persistent global issue. Specifically, marine microbiomes have served as complex reservoirs of antibiotic resistant genes. Molecular advancements have enabled exploration of the uncultured microbial portion from hitherto difficult to sample niches such as deeper oceans. The Gulfs of Kathiawar Peninsula have been known for their unique properties like extreme tidal variations, different sediment textures and physicochemical variations. Pelagic sediment cores across four coordinates each of the Gulf of Kutch, Gulf of Khambhat and an open Arabian Sea were collected, processed for metagenomic sequencing and assessed for antibiotic and metal resistome. The dominant genes were mostly resistant to macrolides, glycopeptides and tetracycline drugs. Studied samples divided into three clusters based on their resistome with carA, macB, bcrA, taeA, srmB, tetA, oleC and sav1866 among the abundant genes. Samples from creek of Gulf of Kutch and mouth of Gulf of Khambhat were most diverse in resistance gene profile. Biomarkers observed include gyrA mutation conferring resistance gene in the Arabian Sea; Proteobacteria species in Gulf of Kutch and Arabian sea; while Aquificae, Acidobacteria and Firmicutes species in the Gulf of Khambhat. Region-wise differentially abundant 23 genes and 3 taxonomic biomarkers were proposed for antibiotic resistance monitoring.

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Background: Significant works have been done on the diversity and distribution of porcellanids crabs in Indian coasts. The present work reports and describe porcelain crabs from the western coast of India. Result: Five species of porcelain crabs in three genera are reported from the western coast of India. Morphological descriptions with measurement of the reported species with key characters and distribution status are given. Conclusion: Petrolisthes boscii (Audouin, 1826), P. lamarckii (Leach, 1820), and P. rufescens (Heller, 1861) are commonly distributed along the studied coast. Enosteoides ornatus (Stimpson, 1858) and Pachycheles tomentosus (Henderson, 1893) sparsely occur and are firstly reported from the Gujarat coast.

Present communication reports the community structure and distribution pattern of intertidal invertebrate macrofauna at four shores of the Kathiawar peninsular coastline off the Arabian Sea (India). The selected shores have different levels of human activities. Present report tests three hypotheses; that is, (i) distribution of invertebrate macrofauna in these shores is influenced by space and time, (ii) abiotic factors have a profound influence on the distribution pattern of intertidal macrofaunal assemblages, and (iii) human activities influence the community structure of the intertidal invertebrate macrofauna at these shores. To test these hypotheses, spatiotemporal variations in different ecological indices were studied. A total of 60 species from six phyla were considered for the study. High species diversity was recorded during winter and monsoon seasons in almost all the shores studied. It was also evident that a few environmental factors had a cumulative influence on the distribution pattern of intertidal macrofauna. Significant spatial variations in the species diversity and evenness were also observed. Though the shores studied have similar coast characteristics and climatic conditions, they face different levels of human activities. Therefore, the observed variations in the intertidal faunal assemblage were possibly caused by anthropogenic stress.

Present communication reports the phylogenetic relationship between three groups of a marine limpet having different color banding patterns using COI sequencing. Samples were sequenced for mtDNA COI gene using universal primer. Comparative BLAST revealed that all three types were around 99.59% identical with Cellana karachiensis, first record of this species from Indian coasts. Apart from the morphological variations, the mtDNA COI gene analysis revealed around 1% nucleotide variations between these three types. The observed dissimilarity in COI sequences was possibly too little to consider these types as three different species. The derivation of amino acid positions indicated that these types could possibly be a complex of three cryptic species of C. karachiensis. The study proposes that the Oman and Indian populations of C. karachiensis might have derived by allopatric speciation due to geographical isolation. The group of these three cryptic species, sharing same habitat between themselves, possibly showed sympatric speciation.

The present study reports the phylogenetic relationship of six zoanthid species belonging to three genera, Isaurus, Palythoa, and Zoanthus identified using systematic computational analysis of mtDNA gene sequences. All six species are first recorded from the coasts of Kathiawar Peninsula, India. Genus: Isaurus is represented by Isaurus tuberculatus, genus Zoanthus is represented by Zoanthus kuroshio and Zoanthus sansibaricus, while genus Palythoa is represented by Palythoa tuberculosa, P. sp. JVK-2006 and Palythoa heliodiscus. Results of the present study revealed that among the various species observed along the coastline, a minimum of 99% sequence divergence and a maximum of 96% sequence divergence were seen. An interspecific divergence of 1-4% and negligible intraspecific divergence was observed. These results not only highlighted the efficiency of the COI gene region in species identification but also demonstrated the genetic variability of zoanthids along the Saurashtra coastline of the west coast of India.

Present study reports the habitat preference and spatiotemporal variations in the population abundance of limpetsCellana karachiensisandSiphonaria siphonariainhabiting rocky intertidal zones of Veraval coast, Kathiawar Peninsula, India. The entire intertidal zone of the Veraval coast was divided into five microsampling sites based on their substratum type and assemblage structure. Extensive field surveys were conducted every month in these microsampling sites and the population abundance of two limpet species was analyzed using belt transect method. The results revealed thatC. karachiensiswas the dominating species at microsampling Site-1 (having rocky substratum) possibly due to its ability to tolerate high desiccation, salinity, and temperature fluctuations, while theS. siphonariawas found to be the most dominating species at microsampling Site-2 (having rocky substratum with abundant algal population) possibly due to their preference for the perpetual wet areas. The study also indicated thatS. siphonariapreferred upper littoral zone where the green algae were abundant whileC. karachiensispreferred the spray zone, where it faces almost no competition for space and food with other molluscs. The condition of the spray zone is very harsh for other species to survive.

This paper reports seven species of opisthobranchs from the intertidal zone of the south Saurashtra coastline off the Arabian Sea, Kathiawar Peninsula, west coast of India. Field surveys were undertaken along the intertidal zones of south Saurashtra coast during 2012–2014. In this study, seven species belonging to six families were recorded, of whichHaminoea ovalis, Flabellina bicolor, Phidiana militaris, Baeolidia palythoaeandSakuraeolis gujaraticaare new records from this coastline.