scholarly journals First record of exotic alligator gar, Atractosteus spatula (Actinopterygii: Lepisosteiformes: Lepisosteidae), from Ganga River system, India: A possible threat to indigenous riverine fish diversity

2021 ◽  
Vol 51 (4) ◽  
pp. 385-391
Author(s):  
Ranjan Kumar Manna ◽  
Archisman Ray ◽  
Supriti Bayen ◽  
Tanushree Bera ◽  
Debashis Palui ◽  
...  

A new record of an exotic alligator gar, Atractosteus spatula (Lacepède, 1803), from an open wetland of the Ganga River was presented in this paper and discussed along with the environmental parameters. Entry of the exotic fish into the natural system was probably a result of uncontrolled ornamental fish trading. Considering threats of this predatory fish to become invasive and disturb riverine fish diversity, possible ways to avoid such risk have been discussed.

2021 ◽  
Vol 24 (2) ◽  
pp. 43-51
Author(s):  
Atul K. Singh ◽  
Sharad C. Srivastava ◽  
Pushpendra Verma

Abstract In order to assess the distribution pattern and understand the prevailing factors for predicting further expansion of an exotic fish Oreochromis niloticus, this study was undertaken in the Ganga river flowing through the state of Uttar Pradesh using MaxEnt model. The authors report the distribution pattern of O. niloticus and prevailing causative factors mounting the expansion of O. niloticus in the Ganges based on MaxEnt modeling technique. The presence only occurrence data-set for this invasive species was prepared from the field data and also from data collated from the authenticated publications of different fisheries researchers. The data-set was analyzed with environmental and topographical variables typically incorporating seasonal and temporal variability using MaxEnt, a maximum entropy algorithm which showed that the area under curve was much closer to 1 ( 0.999). The model predicted elevation as the most influential predictor variable with permutation importance of 69.2% followed by slope_steepness (10.1%), Tmax_1 (7.3%) and Srad_5 (6.8%). The findings from the results suggest that invasive O. niloticus tend to spread in rivers where elevation is lower as well as slope_steepness of the river is higher and thus indicated that invasion might be higher in the downstream of the river. The model suggests that topography and its derived variable are the most significant predictors for distribution of invasive O. niloticus. The results of this study also confirm that the water qualities of the Ganga river are suitable for O. niloticus and if the model is supplemented with water quality variables data, the influential predictor variable in water quality can be well investigated with permutation importance.


Author(s):  
Suchismita Medda ◽  
Santi Ranjan Dey

Murshidabad is a district of West Bengal, India and situated on the eastern bank of river Hooghly, a distributary of river Ganga. Although, many studies on fish ecology and fish systematics have been conducted largely to improve fisheries but fish diversity and their distribution pattern from conservation point of view have never been adequately addressed in the Ganga River. In this present study priority was given to prepare a consolidated list of fish fauna that have been found in the part of river Ganga which flows through the District Murshidabad. 74 species belonging to 9 orders and 24 families are found in the river Ganga of Murshidabad district. Family Cyprinidae representing highest number of species viz. 21. The order Cypriniformes is represented by 26 species followed by order Siluriformes containing 20 species.


2006 ◽  
Vol 54 (6) ◽  
pp. 399 ◽  
Author(s):  
S. G. Height ◽  
G. J. Whisson

Exotic finfish and crayfish have been translocated into Western Australia for more than 100 years. Deliberate stocking and subsequent escape from man-made impoundments have resulted in widespread distribution of non-native yabbies (Cherax albidus) and the exotic redfin perch (Perca fluviatilis) in the State’s south-west. Both species are considered invasive and are known to compete with indigenous species for resources. The nature and degree of impact on native marron (Cherax cainii) is unclear and the subject of current debate. Other researchers have hypothesised that invasive species modify their behaviour in the presence of predators in a more rapid and advantageous manner than native species. This greater behavioural plasticity can result in displacement of indigenous species and successful colonisation of invaders. The aim of this study was to investigate behavioural responses of an indigenous crayfish (C. cainii) and an invasive crayfish (C. albidus) to odours from a native predator (Tandanus bostocki) and an exotic predatory fish (P. fluviatilis) present in Western Australia. Crayfish behaviour was observed in individual glass tanks following the addition of odours from native (T. bostocki) or exotic (P. fluviatilis) finfish predators. Marron exhibited minor behavioural modifications when presented with odours from native or exotic finfish. In contrast, the invasive yabby showed greater detection of odours, displaying significant changes in behaviour (P < 0.05). Yabbies also appeared to distinguish between food odour (commercial crayfish feed) and predator odour; however, neither marron nor yabbies displayed behaviour indicating that they could distinguish between a native or exotic fish predator. Results support the hypothesis that invasive crayfish species have a greater capacity for behavioural plasticity than non-invasive crayfish.


Author(s):  
Lavinia Iancu ◽  
Cristina Purcarea

Abstract The present study represents the first report on the presence of Meroplius fukuharai (Diptera: Sepsidae) in Romania. The research area was located in Bucharest. Meroplius fukuharai was recorded during an experiment for investigating necrophagous insect species dynamics. Adult specimens were sampled during the summer (August 2013) from swine carcasses at the beginning of the advanced decay stage. The species had a sporadic occurrence, only four male specimens being sampled and identified both morphologically and genetically during the four-month survey. The recorded environmental parameters during the sampling period showed an air temperature of 28-33°C and a relative humidity of 53-57%. This report on the presence of M. fukuharai in Romania leads to the expansion of its known distribution range in the South Eastern part of Europe.


2008 ◽  
Vol 14 (3) ◽  
pp. 223-231 ◽  
Author(s):  
R. MENDOZA ◽  
C. AGUILERA ◽  
L. CARREÓN ◽  
J. MONTEMAYOR ◽  
M. GONZÁLEZ

Zootaxa ◽  
2020 ◽  
Vol 4816 (3) ◽  
pp. 392-396
Author(s):  
DAIZY BHARTI ◽  
FRANCISCO BRUSA ◽  
SANTOSH KUMAR ◽  
KAILASH CHANDRA

Catenulida are mostly inhabitants of freshwater ecosystems, like ponds, streams, though the marine species are few (Larsson and Willems, 2010). About 110 species of catenulids are known worldwide, with most of the studies conducted in South America (Marcus, 1945a, 1945b; Noreña et al., 2005), North America (Kepner and Carter 1931; Nuttycombe and Waters, 1938) and Scandinavian Peninsula (Luther, 1960, Larsson and Willems, 2010; Larsson et al., 2008). The diversity of catenulids from India has not been studied intensively; however some reports on other turbellaria exists for the country (Annandale, 1912; Whitehouse, 1913; Kapadia, 1947; Basil and Fernando, 1975; Apte and Pitale, 2011; Kalita and Goswami, 2012; Venkataraman et al., 2015). The genus Stenostomum, however, has been studied extensively around the world with identification of over 60 species (Tyler et al., 2006-2016). This is first report of the genus from India. The present study was part of the project to catalogue the diversity of free living protozoan ciliates from the Hooghly stretch of the Ganga River during which the flatworms were found. The worms were studied based on the live observations, with recognition of characters which led to its identification. This study serves to fill knowledge gap in the freshwater flatworms from India. 


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