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Technical Documentation, State of the Ecosystem Report

76 Stomach fullness

Description: Stomach Fullness

Found in: State of the Ecosystem - Mid-Atlantic (2020), State of the Ecosystem - New England (2020)

Indicator category: Database pull with analysis

Contributor(s): Laurel Smith

Data steward: Kimberly Bastille

Point of contact: Kimberly Bastille

Public availability statement: NEFSC survey data used in these analyses are available upon request (see Food Habits Database (FHDBS) for access procedures). Derived stomach fullness data are available.

76.1 Methods

An index of stomach fullness was calculated from NEFSC autumn bottom trawl food habits data, as a simple ratio of estimated stomach content weight to total weight of an individual fish. Stomach fullness may be a better measure than absolute stomach weight if combining across species into a feeding guild, to prevent larger animals with heavier stomachs from dominating the index. An average stomach fullness was calcuated annually for each species and Ecological Production Unit (EPU).

76.1.1 Data sources

Stomach contents weights and individual fish weights (both to the nearest gram) were collected on the NEFSC bottom trawl surveys from 1992-present aboard RVs Albatross IV, Delaware II and the Henry B. Bigelow (see Food Habits Database (FHDBS) for access procedures).

76.1.2 Data extraction

NEFSC food habits data summarized in the R data file allfh.RData were obtained from Brian Smith () for this index.

76.1.3 Data analysis

The stomach fullness index was calculated using the R script found here.

76.1.4 Data processing

Fish stomach fullness index was formatted for inclusion in the ecodata R package using this R code. Stomach fullness was expressed as an annual anomaly for each species in each region.

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