[Submission]: Zooplankton Center of Gravity

[sgaichas]

Data Source(s)

The Northeast Fisheries Science Center has conducted zooplankton surveys since the 1970s.

The dataset through 2022 used in this analysis was obtained from Harvey Walsh.

Data Processing

Data were aggregated into groups for analysis (names indicate column names in the dataset linked above):

A lookup of these column headings is here: https://www.fisheries.noaa.gov/inport/item/35054

• Calanus finmarchicus (calfin_100m3) = “calfin” ,
• Large copepods (calfin_100m3, mlucens_100m3, calminor_100m3, euc_100m3, calspp_100m3) = “lgcopeALL”,
• Small copepods (all) (ctyp_100m3, pseudo_100m3, tlong_100m3, cham_100m3, para_100m3, acarspp_100m3, clauso, acarlong_100m3, fur_100m3, ost_100m3, temspp_100m3, tort_100m3, paraspp_100m3) = “smallcopeALL” and
• Small copepods (SOE) (ctyp_100m3, pseudo_100m3, tlong_100m3, cham_100m3) = “smallcopeSOE”.
• Euphausiids = "euph_100m3"
• Zoopvolume = "volume_100m3"

Data were assigned to seasonal blocks

• Spring = January-June
• Fall = July-December

Years were selected for analysis

1982 - 2022

The script that processes input data is available here: https://github.com/NOAA-EDAB/zooplanktonindex/blob/main/data/VASTzoopindex_processinputs.R

Data Analysis

VAST models

VAST is a spatio-temporal modeling framework used for index standardization [@thorson_comparing_2017; @thorson_guidance_2019].

Center of gravity metrics are output from VAST.

Data were pulled from the model outputs using code here: https://noaa-edab.github.io/zooplanktonindex/ZoopCOG.html

Bibiography

No response