Unveiling the molecular identity of the diminutive cyprinid, Horadandia brittani (Teleostei: Cyprinidae), a species endemic to Southern India

BACKGROUND

Horadandia brittani is a small cyprinid fish species initially discovered in the coastal floodplains of southern India. For almost 50 years, the genus Horadandia was monotypic with a single species confined to Sri Lanka. In 1992, a new species H. brittani was described from south-western India. Despite being described as a separate species, H. brittani was later considered a synonym of H. atukorali, but in 2013, researchers recognized it as a distinct species based on morphological differences. Despite this clarification, there was still a need to validate the identity of H. brittani and determine its evolutionary relationship with its closely related species using DNA sequences.

METHODS

To address the uncertainties surrounding the identity of H. brittani, the present study utilized molecular techniques to generate DNA sequences. Sample collection involved obtaining specimens of H. brittani from their natural habitats. Subsequently, DNA was extracted from the collected samples, and the mitochondrial cytochrome C oxidase (COI) gene was amplified using appropriate methods.

RESULTS

The analysis of DNA sequences obtained from the COI gene revealed significant genetic distinctions between H. brittani and H. atukorali. The genetic distance values between these two species ranged from 3.21 to 3.63%, clearly indicating that these two species are genetically separate entities. The study successfully established the phylogenetic relationships between H. brittani and H. atukorali based on the COI gene sequences, further confirming the validity of H. brittani as a distinct and separate species.

CONCLUSION

The findings of this study conclusively demonstrate that H. brittani is a valid and separate species, distinct from H. atukorali. The genetic analysis based on mitochondrial COI gene sequences provided strong evidence for the differentiation between these two species. The molecular data generated in this research can be used to identify H. brittani quickly and accurately in the future.

The Nicobarese tribes and their coastal fishing activities during the COVID-19 pandemic-related restrictions- preliminary findings

We interviewed the Nicobarese tribal community (N = 95) of Car Nicobar Island situated in the Andaman and Nicobar archipelago, India to analyze the impact of COVID-19-related restrictions on their coastal fishing activities. Our surveys revealed a significant reduction (p < 0.001) in the average monthly income and fish catches during pre and post-COVID-19 scenarios. Constraints faced during the pandemic-related restrictions and the possible solutions to reinforce the fishing activities were highlighted for sustainable resource management in Car Nicobar Island.

Policy framework and development strategy for freshwater aquaculture sector in the light of COVID-19 impact in Andaman and Nicobar archipelago, India

The present study was aimed at understanding the impact of COVID-19 pandemic related restrictions on the freshwater aquaculture sector of Andaman and Nicobar archipelago (ANI). We interviewed the freshwater fish farmers (N = 211) covering all the three districts (North and Middle, South Andaman, Nicobar district) of the archipelago. The results revealed the critical issues faced by the stakeholders such as fish seed unavailability, limitations in feeding, insufficient logistical support, movement related restrictions, lack of inputs, manpower shortages, etc. as the important constraints during lockdown. Our surveys also revealed that there was a significant reduction in the income of the farmers post COVID-19 outbreak (p < 0.001). Possible reform strategies that could promote the sector development and resilience were outlined to recover from the COVID-19 impacts. The study also highlights the significance of effective networking among the stakeholders and necessary preparedness measures to be undertaken by the fish farmers to deal with the exigencies. The study also recommends a policy framework to strengthen the planning and management of freshwater aquaculture sector towards the path of sustainability.

Outbreak of hirudiniasis in aquarium-reared albino red-bellied pacu Piaractus brachypomus

We report hirudiniasis caused by the leech Hemiclepsis marginata asiatica Moore, 1924 in albino red-bellied pacu (pirapitinga) Piaractus brachypomus (Cuvier, 1818), constituting the first documentation of a freshwater fish species being affected in India. The outbreak occurred in a tank of an aquarium-fish retailer; infested fish appeared asphyxiated, unable to swim or swimming upside down, with cloudy eyes and body with thick mucus secretion. The prevalence and mortality was 100%, with a mean intensity of 81 leeches per fish. The histopathology of the morbid fish revealed degenerative necrosis, eosinophilic infiltration in the muscle tissue and haemorrhages in the fin membrane. The leech mitochondrial 18S rDNA and 12S rDNA genes were characterised and submitted to GenBank under accession numbers MN380443 (18S) and MK733282 (12S). A maximum likelihood tree was constructed using 12S rDNA gene sequences to demonstrate the phylogenetic position of Hemiclepsis marginata asiatica among its congeners.

A new species of dartfish of the genus Ptereleotris (Teleostei: Gobiidae) from the East Coast of India

Ptereleotris cyanops n. sp. is described from five specimens collected in trawl landings at Chennai, Tamil Nadu, East Coast of India. The new species is unusual among congeners in possessing a wide interdorsal space, its width 2.5-3.2% in SL. The new species resembles P. microlepis in general morphology and coloration, but is readily distinguished from it in lacking a black bar at base of pectoral fin, in having a slightly truncate caudal fin with the 5th and 13th branched rays prolonged as filaments (vs. emarginated caudal fin with absence of any caudal filaments), and in having the second dorsal and anal fin not elevated anteriorly (vs. elevated). Ptereleotris cyanops differs from caudal filaments bearing congeners viz., P. arabica and P. hanae, by the absence of chin barbel (vs. present in both); in having a longer pelvic fin (17.7-18.8 vs. 13.1-15.5% SL in P. arabica), and more anal rays (27 vs. 22-25 in P. hanae).

A new short brown unpatterned moray eel Gymnothorax andamanensis (Muraenidae: Muraeninae) from Andaman waters, India

Gymnothorax andamanensis sp. nov., a new short brown moray eel, is described here on the basis of two specimens collected from Port Mout, Port Blair, South Andaman (11.659327°N; 92.696148°E), caught using baited hand-lines in a sandy habitat at a depth of less than 2 m. The species is characterized in having the dorsal-fin origin before the gill opening, pre-anal length 2.1-2.2, jaw pores with black rim, two branchial pores, predorsal vertebrae 3, preanal vertebrae 57 and total vertebrae 135-136, teeth smooth, three large fang-like median intermaxillary teeth, biserial maxillary and uniserial vomerine teeth, and dentary teeth biserial with two teeth in each side in the second row of the dentary. The new species is compared with all 10 short brown unpatterned moray eels known from the world and two from Indian waters.

Investigation and confirmation of white spot syndrome virus (WSSV) infection in wild caught penaeid shrimps of Andaman and Nicobar Islands, India

White spot syndrome virus (WSSV) is one of the most prevalent, widespread and devastating pathogen associated with shrimp population. The present study was aimed at screening the wild caught shrimps from Andaman and Nicobar Islands (ANI) for WSSV infection. Shrimp samples of different penaeid species including Penaeus monodon, Penaeus indicus, Penaeus merguiensis and Metapenaeus monoceros collected from nine different landing centers across the coast of ANI were screened for WSSV infection. Presence of white spots, a typical clinical sign of white spot disease was observed on the exoskeleton of WSSV infected shrimp samples. Out of 241 shrimp samples, 39 samples of P. monodon were found positive for WSSV by nested PCR. Histopathological examination revealed eosinophilic to basophilic intranuclear inclusion bodies in gill tissue which are typical characteristics of WSSV infection. Nucleotide sequence of WSSV isolated from ANI showed 100% identity to the sequences of WSSV reported from Thailand, Taiwan, China, Egypt, Mexico, Korea, France and 99% identity to WSSV reported from India. The detection of WSSV in wild P. monodon of ANI further confirms the virus spread and biogeography.

<b>A first report of <I>Redigobius oyensi</I> (de Beaufort, 1913) (Teleostei: Gobionellinae) from Car Nicobar Island, India</b>

Redigobius oyensi (de Beaufort, 1913), a freshwater Data Deficient goby, is reported for the first time from Car Nicobar Island, Andaman & Nicobar archipelago. A short note on its habitat and co-occurring species are discussed in this study.