The following is a description of the data files associated with Strayer, D.L., Fischer, D.T., Hamilton, S.W., Malcom, H.M., Pace, M.L., and C.T. Solomon. 2019. Long-term variability and density-dependence in Hudson River Dreissena populations. Freshwater Biology. Contact for questions about these data: David Strayer (strayerd@caryinstitute.org). LIST OF INCLUDED DATA FILES (all are tables of data in .csv format) Strayer_etal_FWB2019_cohort_density.csv (data on population density, by cohort) Strayer_etal_FWB2019_cohort_shelllength.csv (data on growth in shell length, by cohort) Strayer_etal_FWB2019_condition.csv (data on body condition of zebra mussels) Strayer_etal_FWB2019_sizestructure_quaggahard.csv (data on population size structure) Strayer_etal_FWB2019_sizestructure_quaggariverwide.csv (data on population size structure) Strayer_etal_FWB2019_sizestructure_zebrahard.csv (data on population size structure) Strayer_etal_FWB2019_sizestructure_zebrariverwide.csv (data on population size structure) Strayer_etal_FWB2019_timecourses.csv (time courses of basic population data, including population density, biomass, and filtration rate, and mean body masses) DESCRIPTIONS OF INDIVIDUAL DATA SETS Dataset: “Strayer_etal_FWB2019_cohort_density.csv” Notes: “nd” means that no sample was collected; a blank cell means that estimated density was 0. Cohort = year of settlement of the cohort (cohort=year-class) Density_nn = population density nn months after settlement. Density is given in number per square meter, and pertains to hard substrata (rocks) in the midriver (RKM 151-213) Dataset: “Strayer_etal_FWB2019_cohort_shelllength.csv” Notes: “nd” means that no sample was collected; a blank cell means that estimated density was 0. Cohort = year of settlement of the cohort (cohort=year-class) SL_nn = mean shell length (in millimeters) nn months after settlement. Data apply only to hard substrata (rocks) in the midriver (RKM 151-213) Dataset: “Strayer_etal_FWB2019_condition.csv” Notes: (1) data from 1993 are omitted because “August” samples were taken in early September instead of ~1 August as in other years; (2) “June” data from 1996 are omitted because samples were taken in late May and late June 1996, rather than ~1 June as in other years; (3) dry masses that were recorded as <0 were excluded (this occurred occasionally for very small mussels); (4) residuals >0.7 (i.e., log10[5]) were excluded as probable analytical errors. DM_g = dry mass of the mussel (in grams), without shell, after oven-drying at 60ºC Length_mm = shell length of the mussel (in millimeters), as measured with calipers Log10_DM = log10 of the dry mass (in grams, without shell) Log10_SL = log10 of the shell length, in millimeters Month = month of collection predicted_log10_DM = the predicted log10 dry mass (in grams, without shell), based on a linear regression using all of the data; the regression is log10(dry mass, g) = -4.945 + 2.554 * log10(shell length, mm) residual = residual from the predicted value (i.e., [log10_DM] – [predicted_log10_DM]) Section = section of the Hudson River estuary (L=lower=RKM 99-151, and includes sites PE, PO; M=middle=RKM 151-213, and includes sites CO, SK, Sy, TI; U=upper=RKM 213-247, and includes sites AL, CA) Site = sampling site (AL=Albany, CA=Castleton, CO=Coxsackie, PE=Port Ewen, PO=Poughkeepsie, SK=Stockport, SY=Stuyvesant, TI=Tivoli) Year = year of collection Datasets: “Strayer_etal_FWB2019_sizestructure_quaggahard.csv” “Strayer_etal_FWB2019_sizestructure_quaggariverwide.csv” “Strayer_etal_FWB2019_sizestructure_zebrahard.csv” “Strayer_etal_FWB2019_sizestructure_zebrariverwide.csv” Notes: these four datasets have the same structure (explained below), but contain information on different variables. All of these files contain data on the population densities of mussels of different shell lengths. Files with names containing “quagga” refer to the quagga mussel (Dreissena rostriformis), whereas files containing “zebra” in their names refer to the zebra mussel (Dreissena polymorpha). The terms “hard” or “riverwide” in the file names indicate whether the file contains local densities (i.e., number per projected square meter of rock) in midriver sites (RKM 151-213) (“hard”), or riverwide (RKM 99-247) mean densities on all sediment types (“riverwide”). These files contain a few known but minor errors in assigning specimens to the two species: (1) “zebra” data from August 2010 include a few (~1%) quagga mussels from hard substrata; (2) “zebrariverwide” data from May 2008 include a single quagga mussel from Poughkeepsie; (3) “zebrariverwide” data from August 2008 include a three quagga mussels from Port Ewen. The first column (“BINS”) gives the upper boundary of the bin of shell length (mm); i.e., entries in the row for the BIN=4.99 give the densities of mussels having shell lengths between 4.00 and 4.99 mm The succeeding columns give the sampling dates The cell entries are the densities (in number per square meter) of mussels in that size-class Strayer_etal_FWB2019_timecourses.csv Notes: Be careful! This data set contains two different time variables, depending on whether the population variable was estimated once (time variable = “year”) or twice (time variable = “date”) per year. Biomass_quagga = riverwide biomass of quagga mussels, in August of each year, in grams dry mass (excluding shell) per square meter Biomass_zebra = riverwide biomass of zebra mussels, in August of each year, in grams dry mass (excluding shell) per square meter Body_mass_quagga = mean body mass of quagga mussels, in August of each year, in grams dry mass (excluding shell) Body_mass_zebra = mean body mass of zebra mussels, in August of each year, in grams dry mass (excluding shell) Date = time of sampling, for population variables that were estimated twice per year (see also “year” and note above); applies to density_quagga, density_zebra, and filt_rate Density_quagga = mean riverwide population density of quagga mussels, in number per square meter Density_zebra = mean riverwide population density of zebra mussels, in number per square meter Eggs = estimated riverwide mean annual egg production of both species of Dreissena combined, estimated by combining published estimates of fecundity made at other sites with body size data from our study site; units are number per square meter of river surface; to convert to units of number per liter, divide by 8300 Filt_rate = estimated filtration rate of both Dreissena species combined, in units of m/d (which is equal to cubic meters per square meter per day) Veligers = mean number of veligers counted at our sampling station near Kingston during the growing season (1 May – 30 Sept) ; units are number per square meter of river surface; to convert to units of number per liter, divide by 8300 Year = year for which an estimate applies, for variables that were estimated once per year (see also “date” and note above); applies to biomass_quagga, biomass_zebra, body_mass_quagga, body_mass_zebra, eggs, and veligers