Description

PURPOSE: The primary objective of this survey is to obtain an index of the abundance and biomass of American lobster (Homarus americanus) in the Northumberland Strait. This research survey also provides fisheries-independent information for all of the species captured by the trawl. DESCRIPTION: Catch weight, length frequencies, and biological information for crustaceans and fish caught during the annual July-August research vessel trawl survey in Northumberland Strait (NAFO Division 4T). Abundance indices and spatial distribution patterns of commercial and non-commercial crustaceans and other groundfish. PARAMETERS COLLECTED: The full catch is sorted to species, or lowest taxonomic group possible, and weighed. For lobster, carapace length, sex and carapace condition (i.e. stage of moult) are recorded. For female lobster, the presence or absence of eggs is noted and, starting in 2010, the stage of development of the eggs (i.e. new or old) when present was also recorded. Similarly, for crabs, the carapace width, sex and carapace condition (i.e. stage of moult) is recorded as is the presence or absence of eggs (for females). Fish sampling varied over the years but, starting in 2005, length has been recorded for all fish captured. For large catches, the complete catch is sorted and weighed, but sub-sampling, by species, is used for the other measurements. NOTES ON QUALITY CONTROL: Data are checked for irregularities. SAMPLING METHODS: The Northumberland Strait multi-species survey began in 2001 using a stratified random sampling plan. A random selection of sampling sites within the study area is now used. Sampling is completed annually over a 4-week period in July and August. One hundred ten (110) stations are sampled in Northumberland Strait in water depths greater than 4 m at the lowest normal tide. The survey has employed a 286 Rockhopper trawl for all years from 2001 to 2018, except in 2010 and 2011, when a Nephrops trawl was used. In 2019, a new trawl (called the Northumberland trawl) was used in addition to the Rockhopper trawl. The Northumberland trawl is similar to the 286 Rockhopper trawl, but with a smaller footgear and smaller mesh sizes. At each station, the trawl is towed for a set period of time (recently 15 minutes with the rockhopper trawl and 10 minutes with the Northumberland trawl). USE LIMITATION: To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

Resources

Name	Format	Description	Link
Data dictionary	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/6d61f7b4-39eb-c8a9-a71c-b65d2eca8660/attachments/data-dictionary.csv
Supplementary citation list	PDF		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/6d61f7b4-39eb-c8a9-a71c-b65d2eca8660/attachments/references_6d61f7b4_Northumberland%20Strait%20Mul.pdf
Northumberland Strait Multi-species Trawl Survey Data	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/6d61f7b4-39eb-c8a9-a71c-b65d2eca8660/attachments/sGSL-Northumberland-Survey-FGP.csv
Northumberland Strait Multi-species Trawl Survey Map	Ersi REST		https://egisp.dfo-mpo.gc.ca/arcgis/rest/services/open_data_donnees_ouvertes/northumberland_strait_multi_species_trawl_survey_data/MapServer
Northumberland Strait Multi-species Trawl Survey Map	Ersi REST		https://egisp.dfo-mpo.gc.ca/arcgis/rest/services/open_data_donnees_ouvertes/northumberland_strait_multi_species_trawl_survey_data/MapServer

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