Microplastic contamination in filter-feeding oyster Saccostrea cuccullata: Novel insights in a marine ecosystem.

Microplastic (MP) pollution has become a pressing global concern. Oysters are well-known filter feeders who ingest food by filtering microscopic particles suspended in the surrounding water. Along with organic matter, filter-feeding also causes accidental ingestion of MP by oysters. Hence, the aim of the current investigation is to understand the MP contamination in filter-feeding oysters. A total of 500 specimens of oyster Saccostrea cuccullata collected from the intertidal zone of five sampling locations on the Gujarat coast, India. Specimens underwent analysis following established protocols. Each specimen was found to exhibit MP contamination, showing an abundance of 2.72 ± 1.98 MPs/g. A negative relationship was found between shell length and MP abundance. Predominantly, fibers were documented across all study sites. Black, blue, and red-colored MPs with 1-2 mm sizes were most dominant. MP polymer composition was identified as polyethylene terephthalate and polypropylene. Findings provide baseline information on levels of MPs contamination, which can be used to monitor future effects of MP pollution.

On population structure and breeding biology of burrowing crab Dotilla blanfordi Alcock, 1900.

Background: The present study investigated the population structure and breeding biology of the burrowing brachyuran crab species Dotilla blanfordi Alcock, 1900, which is commonly found on the sandy beach of Bhavnagar, located on the Gulf of Kachchh, Gujarat coast, India. Methods: Monthly sampling was conducted from February 2021 to January 2022 at the time of low tide using three line transects perpendicular to the water line, intercepted by a quadrate (0.25 m2) each at three different levels of the middle intertidal region: 20 m, 70 m, and 120 m. The quadrate area was excavated up to 30 cm and sieved for specimen collection. The collected specimens were categorised into different sexes viz., male, non-ovigerous female, or ovigerous female. For the fecundity study of D. blanfordi, the carapace width (mm) as a measure of size as well as their wet weight (g), size, number, and mass of their eggs were also recorded. Results: The study revealed sexual dimorphism among the population, with females having significantly smaller sizes as compared to males. The overall population was skewed towards females, with a bimodal distribution of males and females. The occurrence of ovigerous females throughout the year suggests that the population breeds incessantly throughout the year, with the highest occurrence in August and September. A positive correlation was observed between the morphology of crabs (carapace width and wet body weight) and the size, number, and mass of eggs.

A Systematic Review on Microplastic Contamination in Fishes of Asia: Polymeric Risk Assessment and Future Prospectives.

Microplastics (MPs) have attracted global concern because of their harmful effects on marine biota; their toxic properties can negatively impact aquatic ecosystems. Fish is an essential source of protein for humans, playing a crucial role in daily food intake. Until recently, MPs were addressed primarily as environmental pollutants, but they are now increasingly recognized as contaminants in the food supply. The present review has comprehended the current knowledge of MP contamination in freshwater and marine fishes of Asia, including 112 peer-reviewed sources from 2016 to 2023. The review recorded 422 Asian fishes (345 marine and 77 freshwater) to be contaminated with MPs. Clarias gariepinus and Selaroides leptolepi have shown maximum MP contamination in the freshwater and marine environments of Asia, respectively. Omnivorous and carnivorous fishes exhibited higher susceptibility to ingesting MPs. Benthopelagic, demersal, and reef-associated habitats were identified as more prone to MP accumulation. In both freshwater and marine environments, China has the highest number of contaminated species among all the countries. Pollution indices indicated high MP contamination in both freshwater and marine environments. A prevalence of fibers was recorded in all fishes. Black- and blue-colored MPs of <500 µm-1 mm size were found dominantly. Polyethylene terephthalate and polyethylene were recorded as the prevalent plastic polymers in freshwater and marine fish, respectively. Overall, the review served as a comprehensive understanding of MP concentrations and variations between species, between feeding habits, and between geographic locations, which can be pivotal for addressing pressing environmental challenges, protecting human health, and fostering global sustainability efforts in the face of escalating plastic pollution. Environ Toxicol Chem 2024;43:671-685. © 2024 SETAC.

Population structure and fecundity of the Xanthid crab Leptodius exaratus (H. Milne Edwards, 1834) on the rocky shore of Gujarat state, India.

Background: The population structure and breeding biology of the Xanthid crab, Leptodius exaratus (H. Milne Edwards, 1834), on the rocky intertidal region of Shivrajpur in Saurashtra coast, Gujarat state, were examined. Method: From March 2021 to February 2022, monthly sampling was conducted during low tide using catch per unit effort in the 500 m2 area. The sampled specimens were categorised into male, non-ovigerous female or ovigerous female. In order to estimate fecundity, the morphology of the crab specimens (carapace width and body weight) as well as the size of eggs, number of eggs and weight of egg mass were recorded. Results: A total of 1,215 individuals were sampled of which 558 individuals were males and 657 individuals were females. The size (carapace width) of males ranges from 5.15 to 29.98 mm, while females ranges from 5.26 to 28.63 mm which shows that the average size of male and female individuals did not differ significantly. The overall as well as monthly sex ratio was skewed towards males with a bimodal distribution while unimodal in females. The population breeds year-round, which was indicated by the occurrence of ovigerous females throughout the year. However, the maximum percentage occurrence of ovigerous females was observed from December to April which indicates the peak breeding season. The size of eggs, number of eggs and weight of egg mass were shown to positively correlate with the morphology of ovigerous females (carapace width and wet weight).

Microplastic prevalence in epipelagic layer: Evidence from epipelagic inhabiting prawns of north-west Arabian Sea.

The escalating global microplastic (MP) pollution severely threatens marine life due to insufficient waste management and widespread single-use plastic. This study focuses on assessing MP contamination in commercial prawns from Gujarat State, India. Ten prawn species collected at five main fishing harbors revealed 590 MP particles in their gastrointestinal tracts, averaging 6.08 ± 5.96 MPs/g and 1.15 ± 0.78 MPs/individual. Significant variations in contamination levels were observed between species and study sites. Pollution indices indicated very high contamination throughout the study sites. Threads were the predominant shape, with blue and black as prevalent colors. Size-wise, 1-2 mm MPs dominated. Polymer analysis identified polyethylene terephthalate, polyurethane, polystyrene, polypropylene, polyvinyl chloride, and acrylonitrile butadiene styrene. The findings provided crucial preliminary information for ecotoxicology and seafood safety investigations regarding MP contamination in commercially important prawns.

Microplastics occurrence in commercial crab (Portunus segnis) from the western coast of India and pollution indices: First investigation and evidence.

Microplastic (MP) pollution has increased drastically due to improper plastic waste management. The present study aimed to investigate the MPs contamination in the commercially important brachyuran crab Portunus segnis of Gujarat State, India. One hundred fifty crab specimens were collected from three principal fishing harbors in Gujarat. The collected specimens were analyzed for MP extraction using a previously documented protocol. The chemical composition of extracted MPs was assessed with ATR-FTIR. The average abundance of MPs contamination was recorded as 0.82 ± 0.58 MPs/g and 2.02 ± 1.48 MPs/individual. Findings of Contamination Factor (CF) revealed that study site Jakhau was identified as a low-contamination site, while Okha and Veraval were considered moderately contaminated. The H index has identified study sites Jakhau and Veraval as class IV risk categories, while study site Okha fell into the class V risk category. PRI value revealed the very high contamination of MPs in all the study sites. The guts were recorded as being more contaminated with MPs than the gills. The average abundance of MP contamination in males (0.77 ± 0.14 MPs/g in Jakhau, 1.19 ± 0.77 MPs/g in Okha, and 0.82 ± 0.43 MPs/g in Veraval) was recorded higher than in females (0.33 ± 0.11 MPs/g in Jakhau, 0.8 ± 0.49 MPs/g in Okha, and 0.75 ± 0.41 MPs/g in Veraval) in all the study sites. The average abundance of MP contamination varied significantly between males and females. Fibers were found dominantly in all study sites, followed by fragments, films, and foams. Black and blue-colored MPs with 1-2 mm sizes were found more abundantly. The chemical composition of the extracted MPs revealed polyethylene, nylon, polyurethane, and polystyrene as polymer compositions. Overall, the present study highlighted the MP contamination in commercially important crabs that can be used as a basis for further studies on ecotoxicology and seafood safety.

Larvicidal proficiency of volatile compounds present in Commiphora wightii gum extract against Aedes aegypti (Linnaeus, 1762).

Aedes mosquitoes are the major cause of several vector-borne diseases in tropical and subtropical regions. Synthetic pesticides against these mosquitoes have certain limitations; hence, natural, eco-friendly, and safe larvicides obtained from plant resources are used to overcome these. In the present study, the larvicidal efficiency of Commiphora wightii against the fourth instar stage of the dengue fever mosquito Aedes aegypti (Linnaeus, 1762) was studied. The gum resin of C. wightii was collected using the borehole tapping method, and hexane extracts in different concentrations were prepared. The fourth-instar larvae were exposed to the extracts, and percent mortality, as well as LC20, LC50, and LC90, was calculated. Volatile compounds of the hexane gum extract were analyzed by Headspace GC/MS, and the sequence of the acetylcholine, Gamma-aminobutyric acid (GABA) receptor, and octopamine receptor subunit of A. aegypti was obtained. It was found that the hexane gum extract was toxic and lethal for larvae at different concentrations. Minimum mortality was observed at 164 µg mL-1 (10%/h), while maximum mortality was at 276 µg mL-1 (50%/h). The lethal concentrations LC20, LC50, and LC90 were 197.38 µg mL-1, 294.13 µg mL-1, and 540.15 µg mL-1, respectively. The GC/MS analysis confirmed the presence of diterpenes, monoterpenes, monoterpene alcohol, and sesquiterpenes in the gum samples, which are lethal for larvae due to their inhibitory activity on the acetylcholinesterase enzyme, GABA receptor, and octopamine receptor subunit. The use of commonly occurring plant gum for the control of mosquitoes was explored, and it was found that the gum of C. wightii had larvicidal activities and could be potentially insecticidal.

A new species and a new record of the amphipod genus Cymadusa Savigny, 1816 (Senticaudata, Ampithoidae) from India.

The present study recorded Cymadusa filosa Savigny 1816 for the first time from India along with the description of a new species Cymadusa kaureshi n. sp. The newly described species C. kaureshi n. sp. can be differentiated from its closely related congeners C. setosa (Haswell, 1879) and C. tattersalli Peart, 2004 in having 3 articulated accessory flagellum of antenna 1 and male gnathopod 2 palm with small proximal knob-like process. The record of Cymadusa filosa Savigny, 1816 by Rabindranath (1972) from Tamil Nadu does not match with the description and illustrations of C. filosa sensu stricto in having mid palmar tooth on male gnathopod 2; antenna 1 with 3 articulated accessory flagellum and gnathopod 1 significantly longer and slender than gnathopod 2. Since the record of Rabindranath (1972) significantly differs from C. filosa sensu stricto, we assume that the Tamil Nadu specimen could be an undescribed species. Moreover, all the previous reports from India of C. filosa are erroneous, and here in this study we report the first confirmed record of C. filosa from India.

Quantitative assessment of microplastic contamination in muddy shores of Gulf of Khambhat, India.

Microplastics (MPs) have become a global concern due to their widespread distribution in marine ecosystems. The present study was aimed to assess MPs contamination in 21 muddy shores sites situated in the Gulf of Khambhat. From each site, five samples (1 kg each) were collected. In the laboratory, the replicates were homogenated, out of which a 100 g sample was used for analysis. The total number of MPs, shape, colour, size and polymer composition of MPs were assessed. The MPs abundance ranged from 0.32 ± 0.18 particles/g (Jampore) to 2.81 ± 0.50 particles/g (Uncha Kotda) among different study sites. Moreover, threads were recorded maximum followed by films, foams and fragments. In case of MPs colour, black and blue coloured MPs occurred dominantly, with sizes ranging from 1 mm to 5 mm. FTIR analysis identified seven different types of plastic polymers, out of which polypropylene was the dominant plastic polymer (32.46 %) followed by polyurethane (32.16 %), acrylonitrile butadiene styrene (14.93 %), polystyrene (9.62 %), polyethylene terephthalate (4.61 %), polyethylene (3.71 %) and polyvinyl chloride (2.51 %). Based on the results of the Contamination factor (CF) value, Alang, Mahua, Ghogha and Uncha Kotda were identified as very high contaminated sites (CF ≥ 6). Pollution Load Index (PLI) value of entire study area revealed the Gulf of Khambhat as a polluted area with MPs contamination (PLI > 1). While value of Hazardous Index (H) identified 12 study sites as class-V risk category (H value > 10,000). Moreover, Pollution Risk Index (PRI) value revealed fifteen sites as very high contaminated sites (PRI > 1200). Pollution indices can be useful in predicting the level of MPs contamination at the study site. Overall, the present study provides the information on MPs contamination in the coastal region of the Gulf of Khambhat that can be used as a baseline data for future studies on the ecotoxicity of MPs on marine biota.

On the taxonomy of Philyra sagittifera (Alcock, 1896) and P. concinnus Ghani & Tirmizi, 1995 (Decapoda, Brachyura, Leucosiidae), with description of a new genus from the Indian Ocean.

The identity of the leucosiid crabs, Philyra sagittifera (Alcock, 1896) and P. concinnus Ghani & Tirmizi, 1995, originally described from Pakistan is clarified. Redescription of the lectotype male of Philyra sagittifera (Alcock, 1896) and fresh material of both species collected from the Persian Gulf revealed that these two species show significant morphological differences from the generic characters of Philyra sensu stricto and other allied genera in possessing three broad tuberculated ridges united to form a "broad-arrow" pointing forwards on the carapace, and male G1 with apical process curved, with or without a spatulate tip. Therefore, a new genus Tirmilyra n. gen. is established to accommodate both species.

Annotated Checklist of Marine Amphipods (Crustacea: Amphipoda) of India.

An annotated checklist of the marine amphipods recorded from Indian waters is compiled from the available peer-reviewed literature. A total of 266 species belonging to 133 genera and 56 families are listed. The maximum numbers of species were recorded from the South Indian Ecoregion (177 species, 98 genera, 47 families), followed by the Western India Ecoregion (101 species, 72 genera, 36 families), the Eastern Indian Ecoregion (99 species, 65 genera, 35 families), the Northern Bay of Bengal Ecoregion (92 species, 53 genera, 29 families), the Maldives Ecoregion (32 species, 24 genera, 16 families), and the Andaman and Nicobar Islands Ecoregion (31 species, 22 genera, 18 families). Notes on the questionable identifications and records of some amphipods are also provided.

An annotated checklist of anomuran species (Crustacea: Decapoda) of India.

An annotated checklist of the anomuran crustaceans recorded from Indian waters is compiled from available published literature. A total of 231 species belonging to 58 genera, 15 families and five superfamilies are listed. The highest number of species was seen in the Andaman and Nicobar Islands Ecoregion (114 species, 37 genera, 14 families), followed by the South India Ecoregion (111 species, 41 genera, 14 families), West India Ecoregion (93 species, 36 genera, 14 families), Eastern India Ecoregion (76 species, 29 genera, 12 families), Maldives Ecoregion (34 species, 15 genera, 10 families) and Northern Bay of Bengal Ecoregion (22 species, nine genera, five families). Notes on the questionable identifications and records of some anomuran crabs are also provided.

Quantitative assessment of microplastic in sandy beaches of Gujarat state, India.

The present study was carried out to quantify microplastic prevalence among 20 sandy beaches on the Gujarat coast. Beaches were categorised into three different classes, viz. low-impacted sites, moderately impacted sites, and highly impacted sites based on anthropogenic pressure. Microplastic (MP) (≤ 5 mm) contamination on the beaches varied with an average of 1.4 MPs/kg to 26 MPs/kg sediment. Sutrapada site-1 and Porbandar showed the highest and lowest mean abundance of microplastics, respectively, among 20 selected beaches. Out of the total assessed microplastics, threads were the maximum (89.98%), followed by the films (4.75%), fragments (3.36%) and foam (1.89%). In terms of colour and size, different microplastics were recorded in this study. The chemical composition of microplastics was identified by ATR-FTIR as polypropylene (47.5%), polyethylene (26%), and polystyrene (25%). Tourism and fishing activities are the possible sources of higher microplastic contamination at highly impacted sites.

Alcolyra, a new genus of leucosiid crab (Crustacea: Decapoda: Brachyura) from India.

The identity of Philyra alcocki Kemp, 1915 (Leucosiidae), a species described from Chilika Lake, India is clarified. The redescription of lectotype male and examination of fresh material collected from Chilika Lake, Odisha state of India revealed that P. alcocki is significantly different morphologically from members of Philyra senso stricto and other allied genera in possessing two tuberculated rows on the branchial region of carapace, and a well-developed tubercle on male thoracic sternite 5 on either side of the sternopleonal cavity. Therefore, a new genus Alcolyra n. gen. is established herewith for the species.

On the identity of Myopilumnus andamanicus Deb, 1989 (Crustacea: Decapoda: Brachyura: Pilumnidae) from India.

The identity of the poorly known pilumnid crab Myopilumnus andamanicus Deb, 1989 originally described from Neil Island, South Andaman Islands, India, is clarified. A re-examination of the holotype female shows that Deb's taxon is actually a species of Lophoplax Tesch, 1918. Myopilumnus is synonymized with Lophoplax. Lophoplax andamanica n. comb. is redescribed and compared with congeners. This is the first record of Lophoplax from the Indian Ocean.

Redescription of Pseudograpsus intermedius Chhapgar, 1955 (Decapoda, Brachyura, Varunidae) from India.

The identity of Pseudograpsus intermedius Chhapgar, 1955 (Varunidae), a crab species found in mangrove habitats of India is clarified. The re-examination of the holotype male and examination of fresh specimens collected from Goa State, India, revealed that P. intermedius shows significant morphological differences from the generic characters of Pseudograpsus. As such, a new genus Chhapgarus n. gen. is established for the species.

Diversity of intertidal, epibiotic, and fouling barnacles (Cirripedia, Thoracica) from Gujarat, northwest India.

The present work studied the diversity of intertidal, epibiotic, and fouling barnacles in the state of Gujarat, northwest India. In total, eleven species belonging to eight genera and five families were recorded in the present study. The Arabian intertidal species Tetraclita ehsani Shahdadi, Chan & Sari, 2011 and Chthamalus barnesi Achituv & Safriel, 1980 are common in the high- and mid-intertidal rocky shores of Gujarat suggesting that the Gujarat barnacle assemblages are similar to the assemblages in the Gulf of Oman Ecoregion. The biogeographical boundary between the Gulf of Oman and Western Indian ecoregions for barnacles should probably extend southward towards the waters adjacent to Mumbai, where Indo-Pacific species of intertidal barnacles dominate. This study provides the first reports of the common widely distributed balanomorph barnacles Striatobalanus tenuis (Hoek, 1883), Tetraclitella karandei Ross, 1971, Amphibalanus reticulatus (Utinomi, 1967), and lepadid barnacle Lepas anatifera Linnaeus, 1758 in Gujarat, as well as of the chthamalid barnacle Chthamalus barnesi in India.

Tritodynamia bengalensis n. sp., a new species of brachyuran crab from West Bengal state, India (Decapoda: Brachyura: Macrophthalmidae).

Tritodynamia bengalensis n. sp. is described on the basis of a male specimen dredged from the shallow coastal waters of West Bengal state, India. The new species is morphologically similar to T. bidentata Yang Tang, 2005 and T. serratipes Anker Ng, 2014, but can be distinguished by the carapace shape, dentition of the pollex, relative length of the dactylus of the third maxilliped, proportions of the propodus of the third pereopod, and structure of the male left gonopod. This is the first record of the genus Tritodynamia from India.

On the identities of Nepinnotheres vicajii (Chhapgar, 1957) and Arcotheres casta (Antony amp; Kuttyamma, 1971) from western India: conspecificity and taxonomy (Decapoda, Brachyura, Pinnotheridae).

The identity of Nepinnotheres vicajii (Chhapgar, 1957) (described as Pinnotheres vicajii) (Pinnotheridae), a pea crab associated with the bivalve Marcia recens (Holten, 1802), is clarified. On the basis of re-diagnosis of holotype male and freshly collected female specimens from its type locality, P. vicajii is now assigned to Arcotheres Manning, 1993. A second poorly known species from India, Arcotheres casta (Antony Kuttyamma, 1971), originally collected from Meretrix casta (Gmelin, 1791) is also synonymized with A. vicajii.

On the two 'forms' of Dotilla intermedia De Man, 1888 (Crustacea: Brachyura: Dotillidae) from the Bay of Bengal, India, with description of a new species.

Two distinct morphotypes of sand bubbler crab (Dotillidae) from eastern India were assigned to Dotilla intermedia De Man, 1888, by British carcinologist, Stanley Kemp in 1919, due to similarities in the areolation of the carapace and the occurrence of these two forms in the same locality. Kemp, however, also illustrated the differences in the morphology of the male thoracic sternums, chelae, and first gonopods and, accordingly, divided D. intermedia into two subcategories which he called the "high form" and the "low form". The recent designation of a lectotype for D. intermedia, which corresponds with Kemp's "high form", makes it possible to recognize the "low form" as a distinct and new species, D. fraternalis n. sp., which is described here. Furthermore, Kemp's synonymization of Dotilla clepsydrodactylus Alcock, 1900, under Dotilla intermedia is affirmed here after examination of the surviving syntypes. A lectotype is selected to stabilize the taxonomy of this species.