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Tyana A. Rudolfsen Doug A. Watkinson Colin Charles Colin Kovachik Eva C. Enders 《Journal of Great Lakes research》2021,47(3):635-647
Understanding relationships between freshwater fishes and habitat is critical for effective fisheries and habitat management. Habitat suitability indices (HSI) are commonly used to describe fish–habitat associations in rivers and other freshwater ecosystems. When applied to large lakes however, standard sampling procedures are inadequate because of larger sampling areas and an increased risk of fish collection bias through one-time observations. Here, we use lake bathymetry, substrate, and multiple fish telemetry detections collected from a systematically deployed receiver grid to develop HSI for four fish species (lake sturgeon, freshwater drum, common carp, and walleye) in Lake Winnipeg. Seasonal variations in habitat use based on water depth and substrate were observed in three of four species. Lake sturgeon remained in shallow locations with predominantly gravel substrate near the mouth of the Winnipeg River regardless of season. Freshwater drum persisted over fine substrate in both summer and winter but had a broader depth range in the summer compared to winter. Common carp shifted from mid-range depths and silt substrate in the summer to shallow depths and gravel substrate in the winter. Walleye showed an unchanging association to fine substrate but expanded from primarily mid-range depths in the summer to include shallower depths in the winter. These findings show how multiple telemetry detections per fish can be combined with hydroacoustic data to provide informative habitat associations for fishes in a large lacustrine ecosystem. 相似文献
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David C. Depew Emily Krutzelmann K. Elise Watchorn Amanda Caskenette Eva C. Enders 《Journal of Great Lakes research》2021,47(3):556-566
The distribution, density, biomass and size-structure of the zebra mussel (Dreissena polymorpha) population in Lake Winnipeg were examined between 2017 and 2019. Zebra mussels have colonized most of the available hard substrate in the south basin and Narrows region, but colonization of the north basin remains low at present, even on suitable substrate. Numerical densities and shell free biomass peaked at 5530 ± 953 m?2 and 64.7 ± 57.9 g shell free dry mass m?2 respectively. The distribution appeared to be strongly limited by substrate type and availability, with further limitations on the distribution imposed by physical disturbance in shallow waters and unsuitable substrate in deeper areas of the lake. Zebra mussels <1 year old dominated the populations, and individuals >18 mm were exceedingly rare. Poor recruitment was observed at sites along the eastern side of the south basin compared to elsewhere in the lake. The proximate causes of these differences in colonization success and recruitment are not clear, but may be in part due to heterogeneous patterns of key physico-chemical environmental conditions such as calcium concentrations required for successful development of juvenile mussels and colder water temperatures in the north basin. This study provides a baseline of information on which to track further expansion of zebra mussels in Lake Winnipeg and assist efforts to develop an understanding of how zebra mussels may affect the ecology of Lake Winnipeg. 相似文献
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The substrate of fluvial systems is regularly characterized as part of a larger physical habitat assessment. These measures are instrumental in meeting the regulatory responsibilities of bioassessment and monitoring programs, and essential to monitoring restoration and rehabilitation success. We describe and validate a commonly used technique for broadly categorizing, and thus characterizing, the substrate in non‐wadeable streams and rivers called the sounding rod method. In brief, a rod, often hollow, is used to probe the substrate of non‐wadeable systems to characterize the substrate. We tested the viability of this method on three different systems by comparing estimated particle class and direct particle measurements. Our results indicate that substrates can adequately be defined into six broad classes (fine‐particle sediment, sand, gravel, cobble, boulder and bedrock) based on size using the sounding rod. Estimated classes were significantly positively correlated to measured classes (τ = 0.83, p < 0.001), and estimates of size class and direct measurements of size were not from significantly different distributions (χ2 0.05,9 = 569.51, p < 0.001). Further, there were significant differences between each category (H = 243.5, 3 d.f., p < 0.001). Although our results affirm that actual substrate class size can be directly inferred from estimated data, it should be noted that soft sediments <200 mm were not always detected. This finding should be carefully considered with individual study objective. Overall, the sounding rod method can be learned quickly, and it is a low‐cost and time‐efficient method for substrate classification. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. 相似文献
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Alewife (Alosa pseudoharengus) abundance and condition are in decline in Lake Michigan, where they not only exert negative effects on several native fish species but also support an economically valuable salmon sport fishery. We investigated feeding-related habitat selection for adult alewives occurring in Lake Michigan's littoral zone by comparing the relative abundance of alewives and non-biting midges (Chironomidae) on littoral rocky and sandy habitats. Both alewives and midges strongly favored hard over soft substrate, with approximately 22 and 23 times greater catch rates on rock than sand, respectively, from June through August 2005. Relative to sand, 92.2% of alewives and 94.8% of emergent midges were captured over rocky habitat. Gut content analysis suggested that the supplement of midge pupae created a benefit for alewives on rocky habitat and that midge emergence may be the basis for rocky habitat selection. Alewife consumption of midge pupae correlated with midge emergence events, frequency occurrence of midges in ale wife diets was significantly greater on rocky habitat, and alewives collected over sand were 1.5 times more likely to have empty stomachs than those collected over rocks. Our results indicate that alewives, the dominant pelagic forage fish in Lake Michigan, are seasonally encountered in littoral rocky communities, where midges are an important seasonal component of alewife diet. 相似文献
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污水深度处理中稳定亚硝化单元工艺的试验研究 总被引:1,自引:1,他引:0
常温下(17~24℃),以二级处理出水为原水,普通硝化污泥为种泥,通过控制曝气量创造较高的O2基质缺乏竞争梯度,成功启动短程硝化反应器,亚硝酸盐积累率高于90%.分别对0.03~0.60 mg/L等9个DO水平下的氮素化合物转化规律及DO、pH和ORP等参数的变化规律进行了研究.结果表明,通过O2基质缺乏竞争途径实现污水深度处理中的稳定亚硝化单元工艺是可行的;DO曲线特征点是最理想的过程控制参数;DO为0.30 mg/L是实现稳定亚硝化最理想浓度;DO、pH和ORP曲线特征点表征的是维持稳定亚硝化过程的转折点,而并非硝化终点. 相似文献
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Ann Marie Gorman Peter J. Whiting Joseph F. Koonce 《Journal of Great Lakes research》2011,37(4):725-731
The conservation of ecologically and economically important species, as well as the management of invasive species, benefits from the ability to make broad-scale predictions of habitat. In this paper, we revised an existing substrate size model based upon stream power to include variables that are readily-quantifiable in a Geographic Information System (GIS) (i.e. stream slope and drainage area). We found no significant difference between slopes measured in the field using surveying techniques and slopes measured in a GIS using a 10 m digital elevation model and high resolution stream dataset. GIS-derived drainage areas and those measured with hand-delineations were also statistically similar. The revised model can be applied using both GIS and field-derived variables to predict median particle sizes from stream power in northeastern Ohio streams draining to Lake Erie. Integration of such models into a GIS could result in regional estimates of the amount and location of preferred fish habitat, which has important applications in fisheries management. In particular, we provide examples of how the predictive substrate model could improve assessment methodologies for invasive sea lamprey, thereby improving eradication measures, and how we may better understand geographic linkages between walleye spawning and nursery habitats. 相似文献
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Sara M. Creque Karen M. Stainbrook David C. Glover Sergiusz J. Czesny John M. Dettmers 《Journal of Great Lakes research》2010
Habitat plays an essential role in shaping aquatic communities yet limited information on the type and distribution of bottom features is available in the form of detailed maps. This is especially apparent in large systems where obtaining such information can be both expensive and challenging. Current maps of Lake Michigan substrate are very general and lack suitable detail of substrate composition and geographic extent of rocky areas. This limits our ability to link biological processes, such as fish spawning, to nearshore habitat and makes it difficult to target structurally complex habitats for sampling. We compiled substrate information gathered over 72 years for Illinois waters and incorporated it into a GIS framework to generate more complete documentation of sediment type and particle size distribution in southwestern Lake Michigan. Sediment data for 1682 sites were standardized to phi units; natural neighbor interpolation was used during GIS analysis to predict sediment type in areas lacking data. Predicted sediment values based on this interpolation had a significant positive relationship with observed sediment values (R2 = 0.92). Further, we linked existing fishery (yellow perch Perca flavescens) data with newly generated substrate information to identify potential associations between spawning site selection and habitat. Tagging data indicated that substrate quality affected the likelihood of yellow perch returning to their release sites in subsequent spawning seasons; higher fidelity was associated with larger, coarser substrate. The generated map will be a useful tool to enhance our understanding of habitat's importance in the Great Lakes, particularly when linked with fishery data. 相似文献
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In 1984, a broad size range of sediment (boulder to sand) was introduced into a high elevation Rocky Mountain stream in southeastern Wyoming, U.S.A. In the spring of 1986, this stream was exposed to a high discharge of 7.5 m3 s−1. From 1985 to 1987 a study was conducted to assess the impact of sediment deposition and flow regime on the aquatic insect community in context of the substrate occurrences of the insect fauna. Using a modified Surber sampler, samples were collected from June through September each year at nine stations which were rated as unimpacted, slightly-impacted, and impacted. The addition of the sediment had minimal effect on the abundance and diversity of aquatic insects. However, high water discharge severely reduced the abundance of aquatic insects and diversity was also negatively impacted. Recovery from these impacts was very rapid. The greatest insect abundance was found in samples taken in gravel and most taxa occurred predominantly on gravel or rubble substrates. 相似文献
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