State of Great Lakes 2017 Technical Report: Indicators to assess the status and trends of the Great Lakes ecosystem
No abstract available.
Great Lakes↗
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A global audit of the status and trends of Arctic and Northern Hemisphere goose populations
This report attempts to review the abundance, status and distribution of natural wild goose populations in the northern hemisphere. The report comprises three parts that 1) summarise key findings from the study and the methodology and analysis applied; 2) contain the individual accounts for each of the 68 populations included in this report; and 3) provide the datasets compiled for this study which will be made accessible on the Arctic Biodiversity Data Service.
Report↗
Status and trends of pelagic prey fish in Lake Huron, 2017
Scientists from the U.S. Geological Survey’s Great Lakes Science Center conducted integrated acoustic and mid-water trawl surveys of Lake Huron in 1997 and annually from 2004-2017. The 2017 survey was conducted during September and included transects in Lake Huron’s main basin, Georgian Bay, and North Channel. Mean lake-wide pelagic fish density was 1582 fish/ha and mean pelagic fish biomass was 10.5 kg/ha in 2017, which represents 96% and 93% of the long-term mean respectively. Mean lake-wide biomass was 23% higher in 2017 as compared to 2016. The total estimated lake-wide standing stock biomass of pelagic fish species, excluding cisco, was ~49 kt (± 10.4 kt), consisting almost entirely of bloater (26.8 kt; 55%) and rainbow smelt (22 kt; 45%), with small contributions from sticklebacks (0.13 kt; 0.26 %), emerald shiner (0.09 kt; 0.18%), and alewife (0.004kt; <0.005%). Age-0 rainbow smelt abundance increased from 155 fish/ha in 2016 to 598 fish/ha in 2017. Biomass of age-1+ rainbow smelt increased from 2.5 kg/ha in 2016 to 4.1 kg/ha in 2017. Age-0 bloater abundance increased from 94 fish/ha in 2016 to 342 fish/ha in 2017. Biomass of age-1+ bloater in 2017 (5.0 kg/ha) remained at levels similar to 2016 (5.2 kg/ha). Emerald shiner density decreased from 38.6 fish/ha in 2016 to 19.5 fish/ha in 2017. Emerald shiner biomass remained at 0.02 kg/ha between 2016-2017 which represented 19% of the long-term mean. Cisco lake-wide mean biomass was estimated at 2.2 kg/ha and mean density was estimated at 5.1 fish/ha in 2017. Bloater and rainbow smelt will likely continue to be the primary pelagic species available to offshore predators in coming years.
Michigan, Ontario↗
Barataria and Terrebonne Bays: Chapter F in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010
The study area included in the Barataria and Terrebonne Bays vignette of southeastern Louisiana spans eastward from Terrebonne Bay to Barataria Bay (Figure 1) and includes portions of Terrebonne, Lafourche, St. Charles, Jefferson, Orleans, Plaquemines, and St. Bernard Parishes. This area falls between the Mississippi River on the east and northeast, extends down through the western shore of Lake Salvador and the Dixie Delta Canal, then runs west to Houma and follows Louisiana Route 315 to the coast; Barataria and Terrebonne Bays are separated from each other by Bayou Lafourche.
Louisiana↗
Mississippi Delta: Chapter G in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010
The Mississippi River Delta, the tip of the longest river in North America, is located in the coastal plains of southeastern Louisiana. The study area included in the Mississippi River Delta vignette of southeastern Louisiana follows the Mississippi River southward from Port Sulphur within the modern Plaquemines-Balize Delta lobe (Figure 1). It extends eastward through Long Bay into California Bay and then encapsulates most of the land to the east of the river; it extends south into Lake Washington and Lake Robinson, then to the Gulf of Mexico, and includes the land to the west of the river. All of this area is within Plaquemines Parish. The mouth of the Mississippi includes four subdeltas (West Bay, Cubit’s Gap, Baptiste Collette, and Garden Island Bay) which began formation between 1839 and 1891 (Coleman and others, 1998). As of 2010, the total land area from Venice, LA to the gulf was 357.50 square km (138.03 square miles) and had ranged from 208.08 square km (80.34 square miles) to 393.70 square km (152.01 square miles) since 1973 (Couvillion and others, 2011).
Louisiana↗
Mississippi river delta: Chapter G in Emergent wetlands status and trends in the northern Gulf of Mexico: 1950-2010
No abstract available.
Louisiana↗
Monitoring and evaluating trends in sediment and water indicators
No abstract available.
Book chapter↗
Extended Abstract: Geologic evaluation of regional production trends in the Upper Cretaceous Austin Chalk
The Upper Cretaceous Austin Chalk, which extends across Texas and Louisiana, is characterized by reservoirs that produce oil, gas, and in some cases, anomalously large amounts of water. Reservoirs typically have low matrix permeability and contain natural fractures. Horizontal drilling has been used to enhance and connect these fracture systems to drain the reservoir more effectively. Although the formation contains continuous (unconventional) reservoirs, it behaves as a hybrid system, wherein varied geologic settings yield both continuous and conventional accumulations.
Louisiana, Texas↗
Status and Trends in the Lake Superior Fish Community, 2017
In 2017, the Lake Superior fish community was sampled with daytime bottom trawls at 76 nearshore and 36 offshore stations. Spring nearshore and summer offshore water temperatures in 2017 were similar to slightly cooler than the 1991-2017 average. In the nearshore zone, a total of 28,902 individual fish from 27 species or morphotypes were collected. The number of species collected at each station ranged from 0 to 13, with a mean of 5.5 and median of 5. Lakewide nearshore mean biomass was 3.8 kg/ha which was below the long-term average of 8.7 kg/ha and the median lakewide biomass was 1.8 kg/ha. which was similar to the long-term average median value of 1.9 kg/ha. Lake Whitefish, Rainbow Smelt, Bloater, Longnose Sucker, and lean Lake Trout were the species with the highest lakewide average biomass. In the offshore zone, a total of 16,674 individuals from 13 species were collected lakewide. The average and median observed species richness at each station was 3.8 and 4 species, respectively, and ranged from 2 to 6 species. Deepwater Sculpin, Kiyi, and siscowet Lake Trout made up 99% of the total number of individuals and biomass collected in offshore waters. Mean and median lakewide biomass for all species in 2017 was 6.8 kg/ha and 6.6 kg/ha, respectively. This was similar to the long-term mean of 6.9 kg/ha and greater than that observed in 2014-2016. Nearshore average larval Coregonus densities in 2017 were greater than observed in any previous year; whereas offshore larval Coregonus densities were much less than observed in previous years.
Lake Superior↗
Results of the acid rain program: Status and trends of emissions and environmental impacts (1990–2002)
Both SO2 and NOx emissions from power generation sources have significantly declined under Title IV. In 2002, SO2 emissions from Title IV-affected sources totaled 10.2 million tons and NOx emissions from all Title IV-affected sources totaled 4.5 million tons, down 35% and 33% respectively from 1990 levels. Sources in states with the highest emissions continue to reduce their emissions the most, and there have been no significant geographic shifts in emissions. The benefits of these emission reductions include improvements in air quality (which are expected to lead to significant human health benefits), broad-scale reductions in sulfate deposition, and improvements in visibility. While surface waters in some areas have begun to show signs of recovery from acidification, acidification is still occurring in many areas. Although there have been no broad-scale regional reductions in nitrogen deposition, nitrogen deposition has declined in some areas, benefiting some nitrogen-sensitive forests and coastal waters and acid-sensitive lakes and streams.
Book chapter↗
Status and trends of prey fish populations in Lake Michigan, 2018
The U.S. Geological Survey Great Lakes Science Center has conducted lake-wide surveys of the fish community in Lake Michigan each fall since 1973 using standard 12 m bottom trawls towed along contour at depths of 9 to 110 m at each of seven index transects. The survey provides relative abundance and biomass estimates between the 5 m and 114 m depth contours of the lake for prey fish populations, as well as for burbot and yellow perch. The resulting data are used to estimate various population parameters that are in turn used by state and tribal agencies in managing Lake Michigan fish stocks. All seven established index transects of the survey were completed in 2018, although depths 64 m and greater offshore of Frankfort could not be completed due to excessive dreissenid mussel biomass on our multiple tow attempts. Mean biomass of alewives in 2018 was estimated at 0.54 kg/ha, which was the highest value since 2013, but still only 6.7% of the long-term average (7.96 kg/ha). Age distribution of alewives remained truncated with no alewife age exceeding 5 years. Bloater biomass was 2.60 kg/ha in 2018, relatively unchanged from 2017, but still only 14% of the long-term average. Round goby biomass was 1.25 kg/ha in 2018, the 3rd largest estimate in the time series and 62% higher than the average since they were first sampled in 2003. Rainbow smelt biomass was 0.45 kg/ha, which was the highest since 2006 but only 21% of the long-term average. Likewise, deepwater sculpin biomass was 1.30 kg/ha in 2018, which was the highest since 2007 but only 20% of the long-term average. Slimy sculpin biomass was only 0.07 kg/ha in 2018, and similar to the very low levels estimated since 2012 and only 17% of the long-term average. Ninespine stickleback remained very rare in 2018 (0.004 kg/ha), and only 1% of the long-term average. Overall, the total prey fish biomass (sum of alewife, bloater, rainbow smelt, deepwater sculpin, slimy sculpin, round goby, and ninespine stickleback) in 2018 was 6.22 kg/ha, roughly 65% greater than in 2017 but still only 17% of the long-term average. With respect to other species of interest, burbot biomass was only 0.04 kg/ha in 2018 (18% of the long-term average) and no age-0 yellow perch were caught in 2018, indicating a weak year-class.
Lake Michigan↗
Status and trends in the Lake Superior fish community, 2019
The Lake Superior fish community was sampled in 2019 with daytime bottom trawls at 76 nearshore and 35 offshore stations distributed throughout the lake. In the nearshore zone, 25,131 fish from 24 species or morphotypes were collected. The number of species collected at nearshore stations ranged from 0 to 15, with a mean of 5.6 and median of five. Nearshore mean biomass was 5.7 kg/ha which was similar to the past twenty-year average of 5.2 kg/ha and less than the 42-year period-of-record mean of 8.5 kg/ha. Lake Whitefish, Rainbow Smelt, Longnose Sucker, Bloater, lean Lake Trout, Cisco, Burbot, and siscowet Lake Trout had the highest total collected biomass. In the offshore zone, 13,145 fish from 11 species or morphotypes were collected. The number of species collected at offshore stations ranged from two to six, with a mean 3.6 and median of four. Deepwater Sculpin, Kiyi, and siscowet Lake Trout made up 99% of the total number of individuals and biomass collected in offshore waters. Mean and median offshore biomass for all species in 2019 was 7.0 kg/ha which was greater than the past eight-year average of 6.6 kg/ha. Recruitment, as measured by age-1 densities, was near the period-of-record lakewide average for Lake Whitefish (7 fish/ha) and Rainbow Smelt (137 fish/ha) and was lower than the period-of-record lakewide average for Bloater (4 fish/ha), Kiyi (1 fish/ha), and Cisco (<1 fish/ha). Lakewide average age-1 Cisco densities have been estimated at <1 fish/ha in twelve of the last twenty years. Survival of Coregonus species to age-1 continues to be a major concern of fishery managers.
Lake Superior↗
Status and trends of the Lake Huron prey fish community, 1976-2019
The USGS Great Lakes Science Center has assessed annual changes in the offshore prey fish community of Lake Huron since 1973. Assessments are based on a bottom trawl survey conducted in October of each year and an acoustics-midwater trawl survey, which began in 2004 and is conducted in September-October. Both surveys were completed in their entirety in 2019. Prey fish biomass in Lake Huron in 2019 was dominated by two species, Bloater ( Coregonus hoyi ) and Rainbow Smelt ( Osmerus mordax ). In the main basin, prey fish biomass remained below levels observed prior to community-wide declines that began in the early to mid 1990s. Bloater was the most abundant prey fish species in the main basin, whereas Rainbow Smelt was the most abundant prey species in the North Channel and in Georgian Bay. Both surveys suggested that Bloater biomass is increasing in the main basin. Low biomass of invasive species like Alewife ( Alosa pseudoharengus ) and Rainbow Smelt is consistent with fish community objectives focused on restoration of native fish communities. Abundance of invasive Round Goby (Neogobius melanostomus) in 2019 was low relative to 2018. Biomass of the native Cisco ( Coregonus artedi ) continued to increase in the North Channel and Georgian Bay. Biomass of slimy sculpin ( Cottus cognatus ) and Deepwater Sculpin ( Myoxocephalus thompsoni ) in 2019 was down from 2018 but within the range observed over the past decade. Reduced lake productivity, predation by a recovering piscivore community, and shifts in food web dynamics that favor fish production in nearshore environments may prevent prey fish biomass in offshore areas from returning to levels observed prior to the early 1990’s. However, increased biomass of Bloater and Cisco suggests that lake conditions may favor recovery of native coregonids.
Lake Huron↗
Long-term epilimnetic temperature trends in Lake Mendota and Trout Lake, Wisconsin
Warming of lake surface waters has become a concern to limnologists and water managers because a ir temperatures, which directly affect near - surface water temperatures, are projected to increase in Wisconsin (WICCI 2011) as well as globally (IPCC 2018). This projected increase is in addition to the changes in air temperatures that have already occurred in recent decade s (WICCI 2011, NOAA 2017) . The deleterious effects of increased temperatures in lake surface waters have been extensively reviewed ( e.g., Blenckner 2005, Keller 2007, Adrian et al. 2009, George 2010 ) . Briefly , t he exceedance of thermal preferences or tolerances of aquatic biota can cause altered food webs and loss of biodiversity in lakes ( De Stasio et al. 199 6 , Chu et al. 2005, Graham and Harrod 2009, Woodward et al. 2010, Comte et al. 2013 ) . W armer surface water temperature s can result in stronger and longer thermal stratification in deep lakes ( Robertson and Ragotzkie 1990, Hondzo and Stefan 1993, Livingstone 2003, Butcher et al. 2015 ) . This process in turn can cause the duration and extent of hypolimnetic anoxia to increase, thus reducing hypolimnetic refugia needed for cold - and cool - water fish ( De Stasio et al. 1996 , Magnuson et al. 1997, Jeppesen et al. 2012 , Missaghi et al. 2017) . Longer duration of hypolimnetic anoxia can enhance eutrophic ation because of more internal loading of phosphorus from bottom sediments ( Blenckner et al. 2002, North et al. 2014 ) . Of parti cular concern, w armer water temperatures favor the growth of toxic cyanobacteria in eutrophic systems ( Paerl and Huisman 2008, Wagner and Adrian 2009, Kosten et al. 2012 ) . Another effect of warmer lake surface temperature s is increased evaporation that can result in lower water levels ( Spence et al. 2013, Gronewold and Stow 2014 ) .
Wisconsin↗
Status and trends of the Lake Huron prey fish community, 1976-2021
The U.S. Geological Survey Great Lakes Science Center has assessed annual changes in the offshore prey fish community of Lake Huron since 1973. Assessments are based on a bottom trawl survey conducted in October of each year and an acoustics-midwater trawl survey, which began in 2004 and is conducted in September-October. Due to weather delays and continued travel restrictions during 2021, there were no bottom trawl samples off the port of Goderich, Ontario and two acoustic transects were cancelled in Georgian Bay. Prey fish biomass in Lake Huron in 2021 was dominated by two species, Bloater (Coregonus hoyi) and Rainbow Smelt (Osmerus mordax). In the main basin, prey fish biomass remained below levels observed prior to community-wide declines that began in the early to mid 1990s. Bloater was the most abundant prey fish species in the main basin, whereas Rainbow Smelt was the most abundant prey species in the North Channel and in Georgian Bay. Both surveys suggested that Bloater biomass is increasing in the main basin. Low biomass of invasive species like Alewife (Alosa pseudoharengus) and Rainbow Smelt is consistent with fish community objectives focused on restoration of native fish communities. Abundance of invasive Round Goby (Neogobius melanostomus) increased in 2021 relative to 2019-2020. Biomass of the native Cisco (Coregonus artedi) increased in the North Channel in 2021 but remained low in Georgian Bay, possibly as an artifact of reduced sampling. Biomass of Slimy Sculpin (Cottus cognatus) and Deepwater Sculpin (Myoxocephalus thompsoni) in 2021 remained low but within the range observed over the past decade. Reduced lake productivity, predation by a recovering piscivore community, and shifts in food web dynamics that favor fish production in nearshore environments may prevent prey fish biomass in offshore areas from returning to levels observed prior to the early 1990s. However, increased biomass of Bloater and Cisco suggests that lake conditions may favor recovery of native corgonines.
Lake Huron↗