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Diets of NW Atlantic fishes and squid

This page provides diet composition data for 174 species of fish and squid, based on over 123,000 stomach samples collected by the National Marine Fisheries Service between 1973 and 1990 during annual Bottom Trawl Surveys. These surveys were conducted each spring and fall, and occasionally summer and winter, between Cape Fear, North Carolina and Nova Scotia. I provide over 1,000 pie charts and extensive tabular summaries of diets based on data from 1973-80 and 1981-90 separately due to extreme differences in sampling and data processing methods. I STRONGLY discourage anyone from combining these data sets for any analyses, except when prey are lumped to the highest taxa levels (e.g., fish, polychaets, echinoderms, etc.). Do not attempt to examine long term trends in predation on fishes by combining these data sets! During 1973-80, stomach samples were preserved in the field and later processed in the laboratory. Prey weights were recorded to the nearest 0.01 grams. Tables for 1973-80 summarize the diets of 152 species, based on 40,000 samples.   During 1981-90 stomach samples were processed at sea where prey volumes to the nearest 0.1 cc were estimated. Tables for 1981-90 summarizes the diets of 117 species, based on 83,693 samples.  Besides differences in prey measurement units, basic differences in the likelihood of prey identification at specific taxon levels make comparisons among these periods difficult. Invertebrate prey were identified more accurately, and to lower taxonomic levels in the laboratory processed samples (1973-80). In contrast, fish prey were more accurately identified to species, while most invertebrates were identified only to higher taxonomic levels in the field processed samples (1981-90). Consequently, comparisons between these two periods are biased by differences in the probability of identification and should be done cautiously. Throughout the data you will see much lower diversity of fish prey in the 1973-80 data set compared to the 1981-90 data. You will also notice that for most species, predation on fish prey is much greater during the 1981-90 period simply because the fish prey were more likely to be identified.

Scientific and common names of fishes and invertebrates referred to in the following text, tables and charts are based on the American Fisheries Society's standardized names lists whenever possible.  To retrieve tabular data on a species first allow the table to fully load into your browser, then do a text search on the scientific name of the species you are interested in using your browser's FIND or SEARCH option.  Note that some species occur as both predator and prey. To obtain data on the diet of a predator, repeat the search until you find the species listed as a predator in the table heading. Alternatively, to find all predators of a given prey, continue repeating the search until you find all the occurrences of the species within the predator diets. Note, you may want to avoid printing these tables from your browser, as many of them are several hundreds to several thousand of pages long. Instead, you may wish to download the table, or to cut-and-paste sections of interest.

1973-80

1981-90

Species list, sample sizes, and predator length statistics

Predator Diet Composition

   All data pooled

   By season

   By year

   By 10 cm length class

   By Geographic area

   By season and geographic area

Predator identification

   All predators of Prey

Both time periods

   All Predators of Fish Prey1

fishprds.txt

Variable definitions for fields found in the above tables can be found at reptvars.htm