Dataset DOI: 10.5061/dryad.f7m0cfz8x

Description of the data and file structure

1) 2022_TrawlingMasterSheet_rev.xlsx

This dataset contains the otter trawl observations for the 2022 survey year.

Excel sheet tabs are as follows:

Raw_Data --> Site indicates the dredge channel (CH), east control (EC), or west control (WC). Date indicates the calendar date the survey was conducted. Region indicates the corresponding strata quadrant in which the survey was conducted (each control has eight quadrants while the channel has twelve). Family indicates the family associated with an observed individual. Species indicates the genus and species epithet associated with an observed individual. Common Name indicates the regional name associated with an observed individual. Total Number is the count of individuals observed.

Finfish and swimming crabs are enumerated and placed in their respective size bin. Other species such as cnidaria, squid, or shrimp are counted (no size data, number of individuals placed in the Total Number column). For example, if three individuals of a single species are measured and each have a length of 15 cm, this would be noted by placing a '3' in the column labeled '15'; if no individuals are observed within a length bin, then a '0' is entered.

NA represents 'Not Applicable' and is entered if a trawl was empty. 

Fish_AbundRich --> Includes a table showing the number of identified species within each survey date.

Fish_Div --> Contains lists of identified species within each survey date to the lowest taxa. No estimates of diversity are included.

Fish_Biomass --> Includes a table showing the sum of estimated biomass within each strata region during the surveys. This is limited to those species with estimated alpha and beta growth indices.

Fish_BioCalc --> Estimates the biomass (grams) of each species observation (exclusive to those with alpha and beta growth indices within the Species_ID tab). This tab calculates the total biomass within a cell by multiplying the biomass at length (from Fish_BioLen) by the number of individuals observed within a length bin from the Raw_Data tab (ie. calculated biomass * number of individuals within a length bin). 

Fish_BioLen --> Estimates biomass at each length bin for each observed species in from the "Raw_Data" tab. This sheet calculates the biomass of a single individual within a specific size bin. When a species is observed, it used the VLOOKUP function to assign the correct calculated weight (from the Fish_Weight tab) to the cell. 

Fish_Weight --> Estimates the weight (grams) of each species at each length (cm) bin. This utilizes the alpha and beta growth indices (in Species_ID tab and sourced from Fishbase) to calculate the weight of an organism that is a given length. Weight = alpha * (Fish Length ^ beta). 

Species_ID --> A list of species observed within the trawl surveys. Their alpha and beta growth indices are in the last two columns and were sourced from Fishbase. Species whose growth indices are not known or who undergo discontinuous growth (ex. shellfish) contain 'na'.

2) 2023_TrawlingMasterSheet_rev.xlsx

This dataset contains the otter trawl observations for the 2023 survey year. Excel sheet tabs follow that of the previous file, with the addition of the Density tab - which estimates fish density for each species.

3) Trawl_Fish_Data.xlsx & 4) Trawl_Sciaenid_Data.xlsx & 5) Trawl_BlueCrab_Data.xlsx

These datasets contain data sourced from files 1 and 2. However, now the dataset consists of trawl survey abundance by ecological group (ie. Finfish, Sciaenidae, and Blue Crab (Callinectes sapidus). Furthermore, they contain additional information such as trawl area, density per 1000m^2, water quality, and the year.

Trawl Area - estimated area of seafloor swept by the trawl net (square meters), calculated by multiplying the net mouth width by distance traveled.

MeanDepth - the mean of the initial and final recorded depth (meters). 

DFI - Distance from Inlet (in kilometers)

DO - dissolved oxygen concentration (mg/L)

Water quality metrics were collected sparsely, so consider this when deciding if they are applicable to include in any analyses. In some cases, the mean of two water quality readings may be included. Consider that water quality was typically measured only once per strata per survey date.

6) Trawl_Fish_Model.xlsx & 7) Trawl_Sciaenid_Model.xlsx & 8) Trawl_BlueCrab_Model.xlsx

These datasets contain data sourced from files 1 and 2. However, now the dataset consists of trawl survey abundance by ecological group (ie. Finfish, Sciaenidae, and Blue Crab (Callinectes sapidus). Furthermore, they contain additional information such as trawl area, density per 1000m^2, water quality, and the year.

Categorical data variables have been replaced with a group number to better accommodate the creation of Hurdle models. The numbering of categorical variables follows:

 Site: CH - 1; EC - 2; WC - 3

 Strata:  Channel - 1; Control - 2

 Year: 2022 - 1; 2023 - 2

 Date

05/23/2022 - 1; 06/28/2022 - 2; 08/04/2022 - 3;

08/30/2022 - 4; 09/21/2022 - 5; 11/17/2022 - 6;

05/16/2023 - 7; 07/07/2023 - 8; 08/03/2023 - 9;

09/06/2023 - 10; 09/29/2023 - 11; 11/29/2023 - 12

9) Trawl_Metrics.xlsx

This spreadsheet contains all collected metrics for each survey conducted.

Collected metrics include mean depth, mean speed, distance traveled, and area covered.

All --> Contains a list of all trawl surveys and their associated metrics.

Overall_Stats --> Contains the overall minimum, maximum, and mean speeds and trawl areas.

CH --> Contains all trawl survey metrics within the dredged channel (CH).

EC --> Contains all trawl survey metrics within the east control (EC).

WC --> Contains all trawl survey metrics within the west control (WC).

GPS --> Contains a list of all referenced GPS IDs with their associated latitude, longitude, and date. The times listed in the "Date" variable may be incorrect if cross-referenced with the actual time in the CH, EC, or WC tabs (which are correct).

10) Trawl_YSI_Data.xlsx

This spreadsheet contains the mean water quality data observations during the trawl survey. Two observations were collected within each strata during each survey date. Some measurements may be missing due to faulty equipment.

11) 2022_Trawling_RawDataSheet_rev.csv & 12) 2023_Trawling_RawDataSheet_rev.csv

These files contain data originally within the 'Raw_Data' tab from their respective 'TrawlMasterSheet' excel file. Here it is packaged within a csv file for accessibility.

General comment regarding units:

Metric units are utilized throughout the datasheets.

• Weight or biomass is in grams.
• Area is in square meters.
• Depth is in meters.
• Distance from inlet (DFI) is in kilometers.
• Density is in # individuals per 1000 square meters (unless otherwise noted).
• Temperature is in degrees Celsius.
• DO is measured in mg/L.
• Speed is in meters per second (m/s).