mab_inshore_survey.RdThese data are aggregated time series of inshore fishery-independent trawl survey data from the Mid-Atlantic Bight. Surveys are performed biannually in the spring and fall months as part of the Northeast Area Monitoring and Assessment Program (NEAMAP), covering the inshore region between Cape Cod, MA and Cape Hatteras, NC. Cooperative survey efforts are led by scientists at the Virginia Institute of Marine Science.
mab_inshore_surveyThese data contain 248 rows and 4 columns
Var: Specifies variable type, including SOE species groupings and sampling season with stratified mean biomass per tow ("index") or sample coefficient of variation ("cv").
Value: Value of variable Var.
Time: Sampling year.
EPU: Ecological Production Unit (EPU) where sampling occurred.
Stratified mean biomass (kg/tow) was calculated by:
Species catch weights were summed for each tow and within each feeding guild.
Average weight per tow with associated variances and standard deviation for each year/season/stratum/feeding guild combination was calculated.
The final index was then calculated as the sum of the weighted averages of the strata, where the weight of a given stratum was the proportion of the survey area accounted for by that stratum (i.e., stratum area/survey area).
Find more information about these data at http://www.vims.edu/research/departments/fisheries/programs/multispecies_fisheries_research/neamap/index.php.