US Long-Term Ecological Research Network

Biocomplexity at North Temperate Lakes LTER; Whole Lake Manipulations: Rainbow Smelt Removal 2001 - 2009

Abstract
Rainbow smelt (Osmerus mordax) are a harmful invasive species in lakes of northern Wisconsin. Smelt were first detected in Sparkling Lake, Vilas county, WI in 1980 and their population has since increased dramatically. We attempt to remove rainbow smelt from Sparkling Lake through a combined strategy of harvest and predation. If successful, such a strategy might be employed to restore other Wisconsin lakes invaded by smelt to a more natural species assemblage without resorting to piscicides. The data sets presented here report the harvest component of smelt removal. An assessment of the rainbow smelt population, supplementing annual LTER data, was performed during the late summer of 2001. The spring removal effort began in 2002 at ice out using multiple gear types. In 2002, the removal effort also continued from mid to late summer using horizontal gill nets. However, from 2003-2009 we took advantage of smelt spawning behavior and our efforts were condensed to a spring removal at ice-off and we utilized only fyke nets. The total weight of each catch was recorded and length-weights as well as sex ratios were documented for a subset of the catch from each removal event. The removal effort resulted in the removal of the majority of the adult population multiple times. However, smelt are a robust species and the population continuously rebounded from large removal years. As a result, catches have fluctuated from 16kg to nearly two tons. We have observed an overall reduction in fish size and an increase in the proportion of males to females. Sampling Frequency: annually
Dataset ID
218
Date Range
-
LTER Keywords
Maintenance
completed
Metadata Provider
Methods
Setting NetsSet nets in areas of high catch first, moving clockwise around the lake.GPS location of netRecord dates in that locationNumber nets consecutively from first net set. (Nets do not need to be pulled in order they were set.) If a net is moved, keep the same number and add an a, b, c, etc after.Sketch net location on a map with the net number (keep with In-Boat data sheets)Pulling NetsTake lake map with net numbers and In-Boat data sheetRecord date, time, collectors namesAt each net, record net number, number of bags and any comments (note anything unusual)For a zero catch… note if the net was fishing (tipped over, twisted, etc). If there were no problems write NORMAL SET.Try to set the net in exactly the same location. (Over burlap if applicable)Data CollectionIf there is not enough time, please follow this order for priority of data collection.Daily CatchUse Daily Catch sheetRecord date, net number, bag number, number of bags from that netWeigh bags in kilograms. Record.Note if fish were kept for sex determination, length – weight or scales and the number kept.Sex ratioUse Sex sheetRandomly select 2 nets. Sample 50 fish from each net.Record date and net numberWeigh two empty buckets and record weight.Separate fish by sex. Try not to squeeze out eggs/sperm.Count number of males and females. Record.Weigh buckets with males or females in them. Record.Length WeightUse Length Weight sheetSelect a random net and sample 30 fish from itRecord date, net number, if fish were frozenRecord length, weight and sex.Compare to scale sheet. Collect scale sample if category is not filled. Pull scales from behind the dorsal fin. Note on data sheet that scales were taken. Scale envelopes should have date, length, weight, net number and sex of fish on them.
Short Name
BIOSMLT1
Version Number
36

Biocomplexity at North Temperate Lakes LTER; Coordinated Field Studies: Predation Study Data 2000 - 2004

Abstract
These data were collected to track changes in dietary composition, changes in age and growth structure, and changes in species and size of prey of fish predators in Sparkling Lake, Vilas County, WI, USA. Sampling began in May of 2000 and ended in September of 2004. Fish were collected with a boat-mounted electrofishing system, usually by conducting a complete lap around Sparkling Lake shortly after dark. Commonly captured species were rock bass, smallmouth bass, and walleye. Less common species were pumpkinseed sunfish and yellow perch. Dietary Composition: Fish stomach contents were collected by gastric lavage, and fish were released after capture. Stomach contents were sorted and counted by major taxonomic groups, dried in polystyrene weighboats at 57 deg C for 48hrs, and then weighed to 0.001g. The count under a taxonomic group heading indicates how many individuals of that group were found in that diet sample. The mass of that group is given in the adjacent ''net wt'' column. Diets varied across sampling dates and years, with a trend towards decreased abundance of the exotics rusty crayfish and rainbow smelt and increased reliance on native minnows. Prey Data: Fish stomach contents were collected by gastric lavage, and fish were released after capture. Once collected, crayfish and fish prey were measured unless advanced digestion had occurred. If possible, the carapace, right chela and left chela of crayfish prey were measured . Due to digestion, it was usually not possible to get all three measurements. The total length of prey fish was recorded. Young-of-year smelt and crayfish were often too small or digested to measure; these were often just counted. Gut labels on each sampling date correspond with the same gut labels in other datasets. Prey fish and crayfish size and composition varied across sampling dates and years, with a trend towards decreased abundance of rusty crayfish and rainbow smelt and increased reliance on native minnows. Age Growth Data: Scale samples were taken from captured predator fish in the summers of 2000, 2001, 2002, and 2004. Number of sites: 1 - Sparkling Lake Sampling Frequency: 2000: twice; 2001-2004 weekly or biweekly
Core Areas
Dataset ID
128
Date Range
-
LTER Keywords
Maintenance
completed
Metadata Provider
Methods
please see abstract for methods description
Short Name
BIOROTH1
Version Number
7

Biocomplexity at North Temperate Lakes LTER; Coordinated Field Studies: Fish Individual 2001 - 2004

Abstract
Fish Data collected for Biocomplexity Project; Landscape Context - Coordinated Field Studies. The eight sportfishes of concern in this dataset; Bluegill, Pumpkinseed, Bluegill-Pumpkinseed hybrid, Largemouthbass, Smallmouthbass, Rockbass, Walleye, and Yellowperch, are the only species for which standard metrics (length (mm) and weight (g)) were taken. All other fish were identified to species and counted. Sampling Frequency: annually Number of sites: 58
Core Areas
Dataset ID
43
Date Range
-
LTER Keywords
Maintenance
completed
Metadata Provider
Methods
(revised 6or28or02)NOTE: This protocol is for each sample site. Eight sites are sampled on each lake.Day CrewEquipment checklist:25 (50 halves) Minnow Traps and Floats Measuring board25 (50 halves) Crayfish Traps and Floats GPS25 slices Beef Liver (6.5 packages) Balances (5, 10, 30g)25 slices of white bread (2 bags) Computer16 Reflectors 12 volt batteriesForceps Data sheetsScale Envelopes and paper (write in rain) Full fuel tankID keys PFDsForceps OarsSmall Tubs AeratorsMinnow nets Measuring tapePlace 1 slice of white bread in each minnow trap and 1 slice of beef liver in each crayfish traps. Minnow traps have 2.5cm diameter openings and crayfish traps have 7.6cm openings.Locate the beginning of each site using the GPS.Set three minnow traps and three crayfish traps in shallow water (approx. 1 m), spaced approximately 15m apart along the 50m riparian transect corresponding with plots A, C, and E. Set the crayfish and minnow traps within two meters of each other.Traps are fished for approximately 24 hours. Crayfish are identified to species, counted per trap, and returned to the lake. Fish caught in either the crayfish or minnow traps are identified to species. Bluegill, pumpkinseed, rock bass, largemouth bass, smallmouth bass, yellow perch, and walleye are measured for total length, weighed and scales taken if necessary (see processing fish below). Any other species caught are identified to species, counted for each trap, and returned to the lake.After pulling the traps at each site, set out the reflectors for electrofishing. The reflectors should be placed 25m before the start of the adjacent riparian transect and 25m after the end of the transect.Night CrewEquipment Checklist:Fishboards (large and small) ElectrofishBoxBalances (5, 10, 30, 60, 100, 500, 1000 grams) ForcepsComputer HeadlampsScale envelopes Cliplights (2)Batteries (2-12 volts) Running lightsFull fuel tanks (generator and boat) AeratorsPFDs GPSOars Dip nets (2)Big Tubs (3) Small tubsRubber boots and gloves (2 pairs) Spotlight (2)Locate each site by finding the reflectors with the spotlight.Electrofish eight 100m transects on each lake after sunset.Follow a 1.5m depth contour along the shoreline, but make sure to electrofish near littoral structure (docks, cwd, etc).Two dipnetters will net all fish regardless of size and place them in the livewell.The driver should record the average DC electrical output in amps and the time taken to complete each transect on the driver datasheet.times Note – Communication between the driver and the netters is essential. It is the netters responsibility to let the driver know about obstructions (logs, rocks, etc) in the water and to let them know if they have to back up for missed fish. Dont be shy, the driver has to hear you over the generator.PROCESSING FISHSort fish into small tubs by species if necessary.Measure the total length (from nose to end of caudal fins pinched together) in mm and weight in grams for these seven species:Bluegill PumpkinseedLargemouth Bass Smallmouth BassRock Bass Yellow PerchWalleyeTake several scales from 5 fish of each of these species (bluegill, largemouth bass, smallmouth bass, yellow perch, and walleye) from each 10mm size class. Keep track of the number of samples taken from each of these species using the scale tally sheet.For yoy fish (for yoy lengths see Table 1), take lengths and weights of 30 fish of each of the above seven species per lake. If possible take several of the 30 required fish from different locations, not all from the same site.Weights should be taken with the appropriate sized spring balance – the fish should be in the mid-range of the scale.Record the date, lake code, site number, fish ID number, species, length, and weight on the scale envelope.Take the scales from behind the left pectoral fin if looking at the fish from the dorsal side. Place at least 5 scales in the scale envelope.Take the third dorsal spine from 5 yellow perch and bluegill for each age class (Table 1). Place it in the scale envelope.Identify all other fish and keep a count for each species for each trap or electrofish run.If a fish cannot be positively identified, preserve it for later identification.Revive fish that have not recovered by holding them by their dorsal surface in the water and gently rocking them to the left and right to move water across the gills.times Note - Remember to hang pesola spring balances to dry after each sampling. If the springs rust they are not reliable. Spring balances are to be calibrated weekly.
Short Name
BIOFISH1
Version Number
6

Biocomplexity at North Temperate Lakes LTER; Coordinated Field Studies: Fish / Crayfish Abundance 2001 - 2004

Abstract
Abundance data for fish and crayfish collected for Biocomplexity Project; Landscape Context - Coordinated Field Studies http://infotrek.er.usgs.gov/doc/wdnr_biology/Public_Stocking/StateMapHotspotsAllYears.htm - Infomation on fish stocking by Wisconsin Department of Natural Resouces in Biocomplexity Lakes. Sampling Frequency: annually Number of sites: 58
Core Areas
Dataset ID
84
Date Range
-
Maintenance
completed
Metadata Provider
Methods
Littoral Zone Surveys: Littoral habitat, fish and macrophyte surveys were performed at eight sites within each of the 55 lakes. The sites were chosen by randomly selecting two points per compass quadrant of each lake. Each year littoral habitat surveys were conducted in June, fish surveys in July and macrophyte surveys in August.Littoral fish were sampled in July of each year, along the shallow areas (water depth greater than 0 and less than2 m) adjacent to the riparian plots. Night electroshocking and crayfish and minnow traps were used to catch fish and crayfish. All species were identified and counted.
Short Name
BIOFISH2
Version Number
8
Subscribe to fish