Nursery habitat characteristics of an invasive, omnivorous fish

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Garrett M. Herigan ◽  
Derek P. Crane ◽  
Kevin L. Kapuscinski
2021 ◽  
Vol 9 (10) ◽  
pp. 2125
Author(s):  
Sheng Bi ◽  
Han Lai ◽  
Dingli Guo ◽  
Xuange Liu ◽  
Gongpei Wang ◽  
...  

Artificial fishery habitats have been extensively used for fishery resource protection and water habitat restoration, and they could attract a large number of omnivorous fishes to gather together. This study intended to reveal the relationship between bacterial communities in the habitats (water and sediment) and intestines of omnivorous fishes (Oreochromis mossambicus, Toxabramis houdemeri and Hemiculter leucisculus). Therefore, we investigated the bacterial communities of samples collected from intestines, water, and sediments in artificial fishery habitats via 16S rRNA metabarcoding high-throughput sequencing technology. The results showed that there were significant differences in the composition, core indicators, diversity and prediction functions in water, sediments, and intestinal microbial communities of the three omnivorous fish. The microbial diversities were significantly higher in habitats than in intestines. The analysis of similarity (ANOSIM) and nonmetric multidimensional scaling (NMDS) results indicated that the intestine microbial communities (T. houdemeri and H. leucisculus) were more similar to the water microbiota, but the intestine microbial communities (O. mossambicus) were more similar to the sediments. Source tracking analysis also confirmed that the contribution of habitat characteristics to omnivorous fish intestinal microorganisms was different; the sediment had a greater contribution than water to the intestinal microbiota of O. mossambicus, which was consistent with their benthic habit. Moreover, the functional prediction results showed that there were unique core indicators and functions between the bacterial community of habitats and intestines. Altogether, these results can enhance our understanding of the bacterial composition and functions about omnivorous fish intestines and their living with habitats, which have provided new information for the ecological benefits of artificial fishery habitats from the perspective of bacterial ecology and contributed to apply artificial fishery habitats in more rivers.


2018 ◽  
Vol 10 (11) ◽  
pp. 12451-12458 ◽  
Author(s):  
Rama Mishra ◽  
Khadga Basnet ◽  
Rajan Amin ◽  
Babu Ram Lamichhane

The Fishing Cat is a highly specialized and threatened felid, and its status is poorly known in the Terai region of Nepal.  Systematic camera-trap surveys, comprising 868 camera-trap days in four survey blocks of 40km2 in Rapti, Reu and Narayani river floodplains of Chitwan National Park, were used to determine the distribution and habitat characteristics of this species.  A total of 19 photographs of five individual cats were recorded at three locations in six independent events.  Eleven camera-trap records obtained during surveys in 2010, 2012 and 2013 were used to map the species distribution inside Chitwan National Park and its buffer zone.  Habitat characteristics were described at six locations where cats were photographed.  The majority of records were obtained in tall grassland surrounding oxbow lakes and riverbanks.  Wetland shrinkage, prey (fish) depletion in natural wetlands and persecution threaten species persistence.  Wetland restoration, reducing human pressure and increasing fish densities in the wetlands, provision of compensation for loss from Fishing Cats and awareness programs should be conducted to ensure their survival.  We also recommend studying genetic diversity of sub-populations, as well as habitat use by radio-tagging. 


2021 ◽  
Author(s):  
Sandra A. Heldstab

AbstractLagomorphs show extensive seasonal variation in their reproduction. However, the factors causing this large variation have so far mostly been investigated intraspecifically and therefore provide only some exemplary comparisons of lagomorph reproductive seasonality. The present study applies both a categorical description (birth season categories 1–5) and a quantitative measure (birth season length in months) to summarize the degree of birth seasonality in the wild of 69 lagomorph species. Using a comparative approach, I tested the influence of 13 factors, comprising six habitat, five life history and two allometric variables on birth season length in lagomorphs. Leporids mainly show non-seasonal birthing patterns with high intraspecific variation. Their opportunistic breeding strategy with high reproductive output and their large distribution areas across wide latitude and elevation ranges might be the reasons for this finding. Ochotonids reproduce strictly seasonally, likely because they live at northern latitudes, are high-altitude specialists, and occur in limited distribution areas. The most important factors associated with variation in lagomorph birth seasonality are mid-latitude, mean annual temperature and precipitation of a species’ geographical range and life history adaptations including fewer but larger litters in seasonal habitats. Birth seasons become shorter with increasing latitude, colder temperatures, and less precipitation, corresponding to the decreasing length of optimal environmental conditions. Leporid species with shorter breeding seasons force maternal resources into few large litters to maximise reproductive output while circumstances are favourable. Since allometric variables were only weakly associated with reproductive seasonality, life history adaptations and habitat characteristics determine birth seasonality in Lagomorpha.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1497
Author(s):  
Vladimir Razlutskij ◽  
Xueying Mei ◽  
Natallia Maisak ◽  
Elena Sysova ◽  
Dzmitry Lukashanets ◽  
...  

Fish, being an important consumer in aquatic ecosystems, plays a significant role by affecting the key processes of aquatic ecosystems. Omnivorous fish consume a variety of food both from pelagic and benthic habitats and may directly or indirectly affect the plankton community as well as the lake trophic state. We conducted a 72-day outdoor experiment in mesocosms with and without Prussian carp (Carassius auratus) to evaluate the effect of this often-stocked omnivorous fish on the plankton community and water quality. We found that the presence of fish increased the biomass of planktonic algae, total and inorganic suspended solids, leading to decreased light intensity in the water and a lower biomass of benthic algae. Fish also prevented development of submerged macrophytes and the establishment of large-bodied zooplankton. However, the fish did not increase nitrogen concentrations and even was lowered total phosphorus levels, in part due to nutrient storage in the fish. We conclude that stocking of Prussian carp should be avoided, or removed where stocked and abundant, to obtain good ecological quality of shallow lakes, characterized by clear water and high abundance of macrophytes.


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