scholarly journals Influence of Local Habitat and Climatic Factors on the Distribution of Fish Species in the Tonle Sap Lake

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 786 ◽  
Author(s):  
Bunyeth Chan ◽  
Sébastien Brosse ◽  
Zeb Hogan ◽  
Peng Ngor ◽  
Sovan Lek
Keyword(s):  
Spatial Distribution ◽  
Fish Species ◽  
Climatic Factors ◽  
Environmental Data ◽  
Fish Diversity ◽  
Fish Biomass ◽  
Tonle Sap Lake ◽  
Tonle Sap ◽  
Bioclimatic Variables ◽  
High Fish

Tonle Sap Lake (TSL) is a highly productive system and hosts a high fish diversity and is of paramount importance for sustaining protein supply for over 15 million Cambodians. Nevertheless, the ecology and factors influencing the spatial distribution of many fishes within the lake remain poorly understood. Using commercial fishing lot catch data from 1994/1995 to 1999/2000, fishing seasons and environmental data (land cover and bioclimatic variables), we describe spatial distribution of the eight most commercially important fish species, and investigate the effects of environmental factors on their distributions in the TSL. We found a strong variability in fish biomass across areas and between species. Specifically, Channa micropeltes was most abundant in the southern and northern sections of the TSL. Channa striata and Trichopodus microlepis were more common in the northern part of the TSL. Cyclocheilos enoplos, Barbonymus gonionotus, Pangasianodon hypophthalmus, and Gymnostomus spp. were abundant in the southern areas of the TSL while Phalacronotus spp. were abundant in few areas in both the north and the south. Flooded forest positively explained the variation in the biomass of P. hypophthalmus, C. striata, C. enopolos, and Phalacronotus spp. Likewise, the lake’s open water positively affects the biomass of P. hypophthalmus, C. enopolos, and Phalacronotus spp., while the agricultural field negatively impacts Gymnostomus spp. biomass distribution. We also found that some areas consistently hosted high fish biomass (e.g., lot 2, Kampong Thom; lot 6, Pursat; lot 2, Battambang, etc.). We, therefore, suggest that fisheries management and conservation planning focus on those areas, considering those areas significance as core fish habitat and important for catching fish.

Predictors of Relative Fish Biomass in Lakes and Reservoirs of Argentina

1990 ◽  
Vol 47 (5) ◽  
pp. 928-939 ◽  
Author(s):  
Rolando Quiros
Keyword(s):  
Data Base ◽  
Climatic Factors ◽  
Organic Matter Content ◽  
Zooplankton Biomass ◽  
Matter Content ◽  
Environmental Data ◽  
Fish Biomass ◽  
Total Organic Nitrogen ◽  
Screening Process ◽  
Lakes And Reservoirs

Relationships between total fish biomass and chlorophyll, nutrient levels, and morphometric and climatic factors are shown for a set of 106 Argentinian lakes and reservoirs. The total data base is highly heterogeneous. Relative fish biomass (CPUE) was estimated from gill net catches. A data screening process was applied to the environmental data base to homogenize it. Nutrient, total organic matter content, and mean depth were most important in explaining relative fish biomass variability between lakes and reservoirs. In most heterogeneous sets total organic nitrogen (TON) explained most of CPUE variability. After screening for limnological anomalies (i.e. turbidity derived from inorganic sources, unsuitable conditions for fish, and TN/TP (total nitrogen/total phosphorus) < 37 (molar basis)), TP and TON were highly correlated with CPUE. Mean annual air temperature was significantly related to fish biomass, but the relationship was not significant after nutrients, morphometry, and environmental oxygen conditions had been accounted for. Several possible causes are discussed. The results support the hypothesis that fish/phytoplankton, and fish/zooplankton biomass ratios are inversely related to lake trophy.

scholarly journals Climate mediates hypoxic stress on fish diversity and nursery function at the land–sea interface

2015 ◽  
Vol 112 (26) ◽  
pp. 8025-8030 ◽  
Author(s):  
Brent B. Hughes ◽  
Matthew D. Levey ◽  
Monique C. Fountain ◽  
Aaron B. Carlisle ◽  
Francisco P. Chavez ◽  
...  
Keyword(s):  
Land Use ◽  
Fish Species ◽  
Climatic Factors ◽  
Hot Spot ◽  
Adult Population ◽  
Fish Diversity ◽  
Nursery Ground ◽  
English Sole ◽  
Nursery Grounds ◽  
Hypoxic Conditions

Coastal ecosystems provide numerous important ecological services, including maintenance of biodiversity and nursery grounds for many fish species of ecological and economic importance. However, human population growth has led to increased pollution, ocean warming, hypoxia, and habitat alteration that threaten ecosystem services. In this study, we used long-term datasets of fish abundance, water quality, and climatic factors to assess the threat of hypoxia and the regulating effects of climate on fish diversity and nursery conditions in Elkhorn Slough, a highly eutrophic estuary in central California (United States), which also serves as a biodiversity hot spot and critical nursery grounds for offshore fisheries in a broader region. We found that hypoxic conditions had strong negative effects on extent of suitable fish habitat, fish species richness, and abundance of the two most common flatfish species, English sole (Parophrys vetulus) and speckled sanddab (Citharichthys stigmaeus). The estuary serves as an important nursery ground for English sole, making this species vulnerable to anthropogenic threats. We determined that estuarine hypoxia was associated with significant declines in English sole nursery habitat, with cascading effects on recruitment to the offshore adult population and fishery, indicating that human land use activities can indirectly affect offshore fisheries. Estuarine hypoxic conditions varied spatially and temporally and were alleviated by strengthening of El Niño conditions through indirect pathways, a consistent result in most estuaries across the northeast Pacific. These results demonstrate that changes to coastal land use and climate can fundamentally alter the diversity and functioning of coastal nurseries and their adjacent ocean ecosystems.

SPATIAL DISTRIBUTION OF FISH DIVERSITY IN GODAVARI RIVER AT AMBAD STRETCH

2019 ◽  
Vol 34 (1-2) ◽  
pp. 81-93
Author(s):  
D. D. BHUTEKAR ◽  
◽  
S. B. AHER ◽  
M. G. BABARE ◽  
◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Fish Diversity ◽  
Godavari River ◽  
Distribution Of Fish

Multidecadal variability of the Tonle Sap Lake flood pulse regime

2021 ◽  
Author(s):  
Aifang Chen ◽  
Junguo Liu ◽  
Matti Kummu ◽  
Olli Varis ◽  
Qiuhong Tang ◽  
...  
Keyword(s):  
Flood Pulse ◽  
Pulse Regime ◽  
Multidecadal Variability ◽  
Tonle Sap Lake ◽  
Tonle Sap

scholarly journals Spatial distribution patterns of soil total phosphorus influenced by climatic factors in China’s forest ecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Zhu ◽  
Anchi Wu ◽  
Guoyi Zhou
Keyword(s):  
Spatial Distribution ◽  
Forest Ecosystems ◽  
Climatic Factors ◽  
Critical Role ◽  
Effect Of Temperature ◽  
P Concentration ◽  
Single Effect ◽  
The Impact ◽  
P Distribution ◽  
Total P

AbstractPhosphorus (P) is an important element in terrestrial ecosystems and plays a critical role in soil quality and ecosystem productivity. Soil total P distributions have undergone large spatial changes as a result of centuries of climate change. It is necessary to study the characteristics of the horizontal and vertical distributions of soil total P and its influencing factors. In particular, the influence of climatic factors on the spatial distribution of soil total P in China’s forest ecosystems remain relatively unknown. Here, we conducted an intensive field investigation in different forest ecosystems in China to assess the effect of climatic factors on soil total P concentration and distribution. The results showed that soil total P concentration significantly decreased with increasing soil depth. The spatial distribution of soil total P increased with increasing latitude and elevation gradient but decreased with increasing longitude gradient. Random forest models and linear regression analyses showed that the explanation rate of bioclimatic factors and their relationship with soil total P concentration gradually decreased with increasing soil depths. Variance partitioning analysis demonstrated that the most important factor affecting soil total P distribution was the combined effect of temperature and precipitation factor, and the single effect of temperature factors had a higher explanation rate compare with the single effect of precipitation factors. This work provides a new farmework for the geographic distribution pattern of soil total P and the impact of climate variability on P distribution in forest ecosystems.

scholarly journals Remote sensing of environmental risk factors for malaria in different geographic contexts

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Andrea McMahon ◽  
Abere Mihretie ◽  
Adem Agmas Ahmed ◽  
Mastewal Lake ◽  
Worku Awoke ◽  
...  
Keyword(s):  
Risk Factors ◽  
Surface Water ◽  
Environmental Risk ◽  
Land Surface ◽  
Climatic Factors ◽  
Environmental Risk Factors ◽  
Environmental Data ◽  
Health Concern ◽  
Irrigated Agriculture ◽  
Boosted Regression Tree

Abstract Background Despite global intervention efforts, malaria remains a major public health concern in many parts of the world. Understanding geographic variation in malaria patterns and their environmental determinants can support targeting of malaria control and development of elimination strategies. Methods We used remotely sensed environmental data to analyze the influences of environmental risk factors on malaria cases caused by Plasmodium falciparum and Plasmodium vivax from 2014 to 2017 in two geographic settings in Ethiopia. Geospatial datasets were derived from multiple sources and characterized climate, vegetation, land use, topography, and surface water. All data were summarized annually at the sub-district (kebele) level for each of the two study areas. We analyzed the associations between environmental data and malaria cases with Boosted Regression Tree (BRT) models. Results We found considerable spatial variation in malaria occurrence. Spectral indices related to land cover greenness (NDVI) and moisture (NDWI) showed negative associations with malaria, as the highest malaria rates were found in landscapes with low vegetation cover and moisture during the months that follow the rainy season. Climatic factors, including precipitation and land surface temperature, had positive associations with malaria. Settlement structure also played an important role, with different effects in the two study areas. Variables related to surface water, such as irrigated agriculture, wetlands, seasonally flooded waterbodies, and height above nearest drainage did not have strong influences on malaria. Conclusion We found different relationships between malaria and environmental conditions in two geographically distinctive areas. These results emphasize that studies of malaria-environmental relationships and predictive models of malaria occurrence should be context specific to account for such differences.

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