Aquatic Ecosystem Health & Management
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Published By Informa Uk (Taylor & Francis)

1539-4077, 1463-4988

2021 ◽  
Vol 24 (2) ◽  
pp. 9-12
Author(s):  
Atul K. Singh ◽  
M. Munawar

2021 ◽  
Vol 24 (2) ◽  
pp. 105-110
Author(s):  
T. T. Ajith Kumar ◽  
Kuldeep K. Lal

Abstract Ornamental fish culture and aquarium keeping have become a booming sector worldwide. It has been observed that a number of stakeholders are involved in introducing exotic ornamentals in India as well, as the takers are interested on variants and new species. Most of the exotic ornamental fishes are also being domesticated in India, since the demand is readily fulfilled through adequate supply to the hobbyists. This sector provides livelihood option to many people and helps to earn millions of dollars to our country every year, however, the invasion of exotic ornamentals in our natural water bodies needs to be assessed, monitored and controlled with due attention as it is a staid menace to our biodiversity. Around 400 species / variants of exotic freshwater ornamentals and around 100 exotic marine ornamental species including invertebrates are found to have introduced in the trade. It is significant to note that an apparent violation in the trade is taking place by concealing the Government of India approval, which is given only for 92 species / variants of fishes for import. Further, as some of the freshwater ornamental fishes currently available in the aquarium trade have invaded through natural water bodies, their impacts need to be studied in detail. To deal with the situation, the proper precautionary approach should be implemented by adopting measures after having proper quarantine, meticulous risk analysis and strategic prevention methods as well. Combined efforts of industry stakeholders with different government agencies, academic and research institutions is required and a suitable protocol has to be formulated for permissible import, sustainable production, supply and management.


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.


2021 ◽  
Vol 24 (2) ◽  
pp. 13-23
Author(s):  
Atul K. Singh

Abstract India, a megadiverse tropical country is grappling with the rising trend of aquatic invasions. Out of 532 introduced non-native fish, 16 species of freshwater aquaculture and aquarium were assessed invasive by using a risk assessment protocol, ‘Fish Invasiveness Screening Test’. Six major identified invasion pathways of the aquatic invasive species were inadvertent or deliberate releases, escapes, contaminants from hatcheries, river corridors, stowaways and unaided introductions. Invasion mechanism further elucidated the factors promoting successful invasion in freshwater ecosystems. For predictive future performance of invasive fish, the concrete and predictive values based on mean abundance by weight was calculated. Over 28.67% and 29.02 % persistent increased yield of the invasive Tilapia and Common Carp respectively was predicted in the Ganga river in the coming decades. Single species Tilapia invasion facilitated multiple species fish invasion, manifesting in invasion meltdown. The trophic changes due to fish invasion exhibited biotic homogenization with trophic downgrading. Aquatic invasive species were found highly competitive interacting with native species causing serious biodiversity loss, health hazards, and economic damage consequently affecting the ecosystem services. In spite of available regulatory approaches and guidelines to manage aquatic invasive species, fish invasion has been on the rise. This paper suggests modifications and stringent implementation of the existing regulatory mechanisms besides adopting linkages, cutting-edge research on invasion science and modern molecular containment tools for effective management.


2021 ◽  
Vol 24 (2) ◽  
pp. 140-155
Author(s):  
Glenn M. Suir ◽  
Douglas A. Wilcox ◽  
Molly Reif

Abstract Shoreline wetlands along Lake Ontario are valuable, multi-functional resources that have historically provided large numbers of important ecosystem goods and services. However, alterations to the lake’s natural hydrologic regime have impacted traditional meadow marsh in the wetlands, resulting in competition and colonization by dense and aggressive Typha angustifolia and Typha x glauca (Cattails). The shift to a Typha-dominated landscape resulted in an array of negative impacts, including increased Typha density, substantial decreases in plant species richness and diversity, and altered habitat and changes in associated ecosystem services. Successful long-term adaptive management of these wetland resources requires timely and accurate monitoring. Historically, wetland landscapes have been surveyed and mapped using field-based surveys and/or photointerpretation. However, given their resource- and cost-intensive nature, these methods are often prohibitively time- and labor-consuming or geographically limited. Other remote sensing applications can provide more rapid and efficient assessments when evaluating wetland change trajectories or analyzing direct and indirect impacts across larger spatial and temporal scales. The primary goal of this study was to develop and describe methodology using U.S. Army Corps of Engineers National Coastal Mapping Program hyperspectral imagery, light detection and ranging data, and high-spatial resolution true-color imagery to provide updated wetland classifications for Lake Ontario coastal wetlands. This study used existing field-collected vegetation survey data (Great Lakes Coastal Wetland Monitoring Program), ancillary imagery, and existing classification information as training data for a supervised classification approach. These data were used along with a generalized wetland schema (classes based on physical and biological gradients: elevation, Typha, meadow marsh, mixed emergent, upland vegetation) to generate wetland classification data with Kappa values near 0.85. Ultimately, these data and methods provide helpful knowledge elements that will allow for more efficient inventorying and monitoring of Great Lake resources, forecasting of resource condition and stability, and adaptive management strategies.


2021 ◽  
Vol 24 (2) ◽  
pp. 33-42
Author(s):  
Aashna Sharma ◽  
Vineet Kumar Dubey ◽  
Jeyaraj Antony Johnson ◽  
Yogesh Kumar Rawal ◽  
Kuppusamy Sivakumar

Abstract Often regarded as a potential threat to the native fish fauna worldwide, the Brown Trout (Salmo trutta), has successfully established its population in the majority of the Himalayan rivers post its introduction dating back to the eighteenth century. Over the years, the species has gained infamy as a sport fish and is considered a profitable source of income to the locals ensuing a heightened propagule pressure due to lack of appropriate management actions. No comprehensive study has been conducted to date in order to understand the mechanism by which the Brown Trout poses threat to the native fish populations. Through the present study, we could assess its competition with the native Snow Trout (Schizothorax richardsonii) to understand the spatial assemblage of both the species across space in Tirthan, a pristine high-altitude river of the western Himalaya. River Tirthan is one of the major tributaries of River Beas traversing for most of its stretch within the protected boundaries of the Great Himalayan National Park Conservation Area. A total of 108 sampling points were chosen from confluence to origin of rivers/streams, ranging from 989 to 3677msl. A total of 28 explanatory variables were recorded at each point. Overall, the Brown Trout adults were found to be greater in relative abundance (66.1%) than the Snow Trout adults (33.9%). The fingerlings of Snow Trout on the other hand, were distinctively high in relative abundance (61.9%) than those of the invasive Brown Trout (38.1%). Non-native trout showed higher abundance in the higher stream orders i.e. in the main streams while natives mostly restricted themselves to the lower order streams. Redundancy analysis (RDA) for species and environmental covariates resulted in 40.75% of constrained variance with higher eigen values for Redundancy analysis1 and Redundancy analysis2. Ward’s minimum variance clustering of Hellinger transformed data revealed sites agglomerating into six reasonable distinct subgroups with respect to species abundances. Immature individuals of non-native and native trout used similar habitat conditions, but they differed in using habitats at adult stage. Our results show a competitive dominance of Brown Trout in terms of higher abundance and maximum space utilization that highlight an urgent action for preventing its introductions to new areas. We recommend a national policy of ‘The Indian Invasive Species Act’ and management level interventions to control overstocking in the areas of established population.


2021 ◽  
Vol 24 (2) ◽  
pp. 130-139
Author(s):  
Sylvia María Cacua Ortiz ◽  
Néstor J. Aguirre ◽  
Gustavo A. Peñuela

Abstract Carbamazepine is a pharmaceutical used in patients with seizures and bipolar disorder, which has been found in wastewater and many water resources. This is due to the inadequate disposal of pharmaceutical waste and the lack of treatment of municipal wastewater, as is the case in Colombia. The two main hydrographic basins of Colombia are the Cauca and Magdalena rivers, which are inhabited by the endemic species Striped Catfish (Pseudoplatystoma magdaleniatum). This has become an endangered species for various reasons, including the high contamination level of these rivers. In 2019, mature adult P. magdaleniatum of both sexes were caught in the Cauca river in Colombia. This was in order to assess the concentration of vitellogenin, as a biomarker of endocrine disruption, resulting from exposure to different levels of concentration of the emerging contaminant carbamazepine for 4 months. These tests were carried out in a fish farm. A significant decrease in the vitellogenin concentration was verified in females at concentrations of 25 µg l-1 and 50 µg l-1, and in males at 50 µg l-1 of carbamazepine, with a significance level of p˂0.05. Carbamazepine could cause a negative feedback in gonadotropin secretion, acting as an estrogen mimicker that causes a decrease in the level of vitellogenin.


2021 ◽  
Vol 24 (2) ◽  
pp. 1-3
Author(s):  
M. Munawar

2021 ◽  
Vol 24 (2) ◽  
pp. 121-129
Author(s):  
Hedi Indra Januar ◽  
Dwiyitno ◽  
Izhamil Hidayah

Abstract Contamination by dangerous heavy metal in the estuarine environment has risen with concern to the safety of coastal fish as seafood. Anthropogenic emission in the coastal areas becomes the primary source of heavy metal pollution in the aquatic environment, which then accumulates in fish species. Therefore, marine fish has a potency to be used as a bioindicator for heavy metals contamination in the coastal environment, since it may vary, as the results of marine hydrodynamics. This research presents seasonal variations (west monsoon, east monsoon, and intermediate monsoon) of heavy metals accumulation in fish from the coastal region of Cirebon, Indonesia. Three types of economic fish (Scatopagus argus, Siganus canaliculatus, and Nibea albifor) were taken, and the heavy metals (Cr, Co, Cu, As, Cd, Hg, and Pb) content were examined by inductively coupled plasma - mass spectrometry (ICP-MS). The results showed a significant difference (p<0.05) of seasonal variation of heavy metals concentration in seawater and sediment. The contamination in seawater was higher during the east monsoon season, while the contamination in sediment was higher during the west monsoon season. The observation was also revealed variation on heavy metals accumulation in fish species. However, this study found no significant correlation (p>0.05) between the concentration of heavy metals in the environment and fish. Consequently, precaution is needed when using fish as a bioindicator for heavy metals contamination in coastal environments.


2021 ◽  
Vol 24 (2) ◽  
pp. 8-8
Author(s):  
S. Ayyappan

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