NAFO fishing division 4T Herring Science Acoustic Survey
Since 1991, an annual fishery-independent acoustic survey of early fall (September-October) concentrations of Herring has been conducted in the sGSL. The standard annual survey area occurs in the 4Tmno areas where both NAFO Div. 4T Herring spawning components aggregate in the fall. The survey uses a random stratified design of parallel transects within predefined strata. Surveys are conducted at night and use two vessels: an acoustic vessel to quantify the fish schools biomass using a hull-mounted 120 KHz split-beam transducer, and a fishing vessel to sample aggregates of fish with a pelagic trawl (details in LeBlanc et al. 2015; see also LeBlanc and Dale 1996).
Trawl samples are used to separate the estimated biomass by spawning component and age, determine species composition, and size distribution for the estimation of the target strength (LeBlanc and Dale 1996; LeBlanc et al. 2015).
A standardized abundance index is generated from this acoustic survey. This index includes catch-at-age data since 1994.
This survey also provides the age-disaggregated acoustic abundance index for ages 2 to 10 for spring spawners and fall spawners.
- Publisher - Current Organization Name: Fisheries and Oceans Canada
- Licence: Open Government Licence - Canada
Data and Resources
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4T Herring Science Acoustic Survey - Data DictionaryCSVEnglish French guide CSV
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4T Herring Science Acoustic Survey - Historic BiomassCSVEnglish French dataset CSV
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4T Herring Science Acoustic Survey TransectsSHPEnglish French dataset SHP
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4T Herring Science Acoustic Survey TransectsESRI RESTEnglish web_service ESRI REST
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4T Herring Science Acoustic Survey TransectsESRI RESTFrench web_service ESRI REST
Contact Information
Delivery Point: 343 Université Ave
City: Moncton
Administrative Area: New Brunswick
Postal Code: E1C 5K4
Country: Canada
Electronic Mail Address: laurie.maynard@dfo-mpo.gc.ca