New Range Extension of Pomadasys andamanensis and Siganus fuscescens to Odisha Coast: Morphological and Molecular Evidence
Two specimens are from each of Pomadasys andamanensis (Mckay and Satapoomin) and Siganus fuscescens (Houttuyn) were collected from Gopalpur-on-sea, Odisha coast, Bay of Bengal. A study on conventional taxonomy interestingly demonstrates not only the first record of appearance of both the species, but also their inclusion to their respective species on the Odisha coast, Bay of Bengal. It was further, strengthened by molecular analysis through DNA barcoding which showed high confidence sequence similarity in their species identification. Moreover, the congruent clustering of both the species according to their morphological identification, strongly support the species identification through DNA barcoding. Above all, the generated time tree with regards to their origin largely agrees with other recent reports based on mitochondrial loci analysis indicates middle to early Miocene sub-epoch for Pomadasys andamanensis and for Siganus fuscescens it occurred sometimes in the late Pleistocene epoch. The migration of these reef-associated fishes is probably for their specific attraction to reef region of Bay of Bengal or/and ecological disturbances in their native region. The overall outcomes confirmed the first ever extensive range of occurrence of these two marine fish species on the Odisha coast, Bay of Bengal.
Biological diversity is rapidly inundating worldwide with unprecedented rates mostly due to human activities (Hubert and Hanner, 2015). Determining the extent to which unprecedented globalization and intensification of human-related threats affect biodiversity, either through the loss of species at particular sites or through changes in range size, requires accurate data on the species distribution (Gaston and Blackburn, 2000). Thus, precise taxonomic identification and delimitation of species is highly necessary for conservation and sustainable exploitation of natural resources and also paramount prerequisites to population genetic, physiological and ecological studies (Butlin et al., 2009). On the other hand, it is also important to know whether economic benefit estimates are stable over time, thus accurate identification of species is additionally consequential for their protection (Lew and Wallmo, 2017).
It is imperative that the ichthyofauna of Bay of Bengal have been well studied for effective conservation and resource management. The Bay of Bengal is the largest marine ecosystem of the world, this pleasant environmental condition, seems to be responsible for introduction of large no of non-native invasive species (NIS). The new alien species are invaded to Bay of Bengal, because of growth, development, reproduction and exploiting the environment for further establishment of their population. Latest record shows that, the existence of invasive species such as Ulua mentalis, Pinjalo pinjalo, Tylosurus crocodilus, Cephalopholis formosa, and Myripristis jacobus to Bay of Bengal at different time period (Barik et al., 2018a, b, c; 2021).
Introduction of several types of marine aquatic noninvasive species may lead to declines or even extinctions of native species; create disturbances in marine ecosystems, increase the transmission of viruses and pathogens, and create significant damage to the flow of the food-chain (Simberloff et al., 2013). Concerns over marine and coastal ecosystems, NIS are being invaded to a new environment because of various human activities such as fisheries, shipping, ornamental and live seafood trades, opening and construction of canals, climate change, habitat modification and aquaculture sites, Marinas may act as hotspots for several aquatic marine biological invasion species and promote further establishment of NIS (Occhipinti-Ambrogi and Savini, 2003; Molnar et al., 2008; Williams et al., 2013). Successful establishment of NIS is due to the species characteristics such as broad range of physiological tolerance, rapid growth, polyphagy, high dispersal ability, high genetic variability, high phenotypic plasticity and human association have been put forward for expanding their range in a new habitat (Chan and Briski, 2017).
Once alien species arrived to a new habitat, these nonnative species must overcome all the physical barrier of geography and survive all the environmental conditions and establish a selfsustaining population (Blackburn et al., 2011). Marine Ecosystem that are tending to susceptible invasion of NIS invading the native habitat, have several criteria of environmental condition such as; few natural enemies, low species diversity, high environmental heterogeneity, a history of habitat disturbances (Levine et al., 2004; Fridley et al., 2007; Melbourne et al., 2007; Herborg et al., 2007; Clark and Johnston, 2011). In addition to that several evolutionary processes such as; genetic drift, adaptation, genetic bottleneck effect, selection and admixture can strongly influence the successful establishment of NIS and helps in proliferation inside a new environment (Sakai et al., 2001; Lee, 2002; Roman and Darling, 2007).
During recent centuries, a no. of nonnative marine fishes are invaded into Bay of Bengal causing community shift in their native habitat. This community shift results alter in species composition, which can indirectly change the structural properties of marine habitat. This change in species composition will provide information about ecological disturbance in both native and nonnative habitat (Scheffer et al., 2001; Scheffer and Carpenter, 2003). In order to find out the amount of change in species composition in a certain habitat, accurate and proper identification of fish species is a prime important work. Earlier studies show that, there are several methods are developed for species identification such as; classical morphotaxonomy, commercial technologies such as immunological assay and cytotaxonomy (Phillips and Ráb, 2001). Frequent change in phenotypic characters, relative costlier process and comparatively lack of expert knowledge are known to be the main drawbacks of earlier studies for species identification. In the recent past, DNA barcoding method has successfully implemented as a robust molecular tool for more accurate species identification (Hebert et al., 2003; Frézal and Leblois, 2008; Leray and Knowlton, 2015). Earlier studies have already proven that mitochondrial cytochrome oxidase-I (COI) is a highly conserved gene used as a barcode marker for most animal species identification (Hebert et al., 2003). The COI-based DNA Barcoding is the most authenticate and versatile method for species identification and have the ability to analyze high rates of sequence changes accompanied with intraspecific divergence at species level (Ivanova et al., 2012; Vences et al., 2012).
Haemulidae is one of the ten diverse, widespread and conspicuous families within the largest sub-order of teleost fishes, the Percoidei (Nelson et al., 2016). They are commonly called grunts, because of their ability to create uproarious sounds by rubbing their pharyngeal teeth together (Burkenroad, 1930). Haemulids have a tendency to congregate during the day and afterward spread out for scavenging around night. The family contains about 145 extant species currently classified in 19 nominal genera (Forese and Pauly, 2017) and grouped into two sub-families i.e. Haemulinae and Plectorhinchinae. The Haemulidae species are morphologically diversified fishes with wondrous and changeable coloration and inhabit the coastal waters in tropical, sub-tropical & temperate inshore reef areas of Atlantic, Indian and Pacific Ocean.
On the other hand, Rabbit fish (Family Siganidae that only include the genus Siganus) are morphologically very uniform group under global fish diversity of coral reefs of order Perciformes (Oh et al., 2007). The members of this family Siganidae are also known as spinefoot, demarcated by different characters like the arrangement of spines (Johnson and Gill, 1998) and exhibits uniform phenotypic characters (i.e. dorsal fins with 13 spines and 10 rays and anal fins with 7 spines and 9 rays). Fishes of the family siganids are the primary consumers of coral reefs and act as an active herbivore, exhibits important component in coral communities. The distribution pattern of family Siganidae is restricted to the Indian Ocean and East Andaman Sea, comprising of 29 nominal species (Froese and Pauly, 2017).
Herein we report recent biological invasion of two marine fishes namely banded grunter Pomadasys andamanensis and mottled spinefoot Siganus fuscescens from Odisha coast, Bay of Bengal, applying the identification of diagnostic morphological and meristic features and subsequently corroborated by DNA barcoding data using single gene marker mitochondrial cytochrome oxidase subunit-I (COI).
Source : New Range Extension of Pomadasys andamanensis and Siganus fuscescens to Odisha Coast: Morphological and Molecular Evidence I InformativeBD
