NECC: Summarizing changes in center of lat/lon between seasons and among years

[aallyn]

To support some of the work being done with folks at UNH, we are interested in calculating the center of biomass for ~41 different species at each year-season time step using the NOAA NMFS spring and fall bottom trawl survey data.

• Review project and task goals with @aallyn
• Gather and pre-process most recent and available NOAA NMFS bottom trawl survey data
• Review Git/GitHub repo and RStudio projects structure and edit trawl repo as needed @aallyn
• Review L.G. code that did something similar for the Pew Project and discuss with @aallyn
• Calculate weight lat/weighted lon/overall center of biomass (https://rdrr.io/cran/SDMTools/man/COGravity.html) for each species, year and season and then the same metrics but for each species and year (ignore season) and then save out as csv files.
• Fit linear model to weight lat/weighted lon/overall center of biomass results for each species and season and calculate the slope of each fitted line to get change in weight lat/weighted lon/overall center of biomass per species per season across years and save as a csv file.
• For each species and year, we will want some measure of how much distance is between the overall center of biomass.

Some updates on @kemills email from 1/12/23 (Also curious if this notifies Kathy...)

• Edit this repo's README with some more information, particularly focusing on orienting folks to the results (most of this is in your email response @carlylovas).
• Create a "Results" folder with subfolders for "plots_maps" and "tables", adding in the time series plots to the "plots_maps" folder and then the output csv tables to the tables
• Edit .csv output table names to be a bit more descriptive (e.g., withoutSeason could be "NEFSC_YearlyDistributionSummaries.csv" and withSeason could be "NEFSC_YearSeasonDistributionSummaries.csv" or something like that?)
• For the seasonal distances, using the dataset that has species - year - distance (meters) between spring and fall: update units to be kilometers, save this intermediate file, and then summarize across years to get an average absolute distance across all years and then summarize by decade to get average distance between decades
• Complete similar analysis, but focus on data through 2009 and then 2010-present
• Explore additional distribution metrics (leading and trailing edge)

1/25 meeting with Carly and Kathy

• Andrew review the GitHub repo and draft email to UNH crowd for Carly to check over and then send along
• Center of Latitude plot of all species paneled by season
• Plot of average distance and rate of change