PURPOSE: These data have been updated following a Canadian Science Advice Secretariat (CSAS) Regional Science Advisory Process. Associated publications are available in the citation section below or will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available. DESCRIPTION: Atlantic herring NAFO 4T biomass estimates for both spring and fall stock components. Values are provided in kilotons (kt) alongside with confidence intervals 50% (spring) and 95% (spring and fall). USE LIMITATION: To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

Atlantic herring NAFO 4T commercial landings data. Landings (in metric tons) per year, per stock (spring spawners and fall spawners), per fishing season (spring and fall) and per gear (fixed and mobile). Two fish samples are taken per week per herring fishing area to determine stock identification (spring or fall spawners). Daily landings data are obtained from DFO Statistics Branch. Stock (spring or fall spawner) data are gathered from port sampling.

Summary The Quebec region of the Department of Fisheries and Oceans (DFO) is responsible for the assessment of several fish and invertebrate stocks exploited in the Estuary and the northern Gulf of St. Lawrence. The commercial catches sampling program is one of the sources of information used to complete these assessments. The data collected by this program, at wharf or at sea, offers among other things the advantage of a relatively large spatio-temporal coverage and provides some of the necessary knowledge to assess the demography and the structure of the exploited populations. This program is implemented by specialized DFO staff whose main mandate is to collect biological data on groundfish, pelagic fish and marine invertebrate species that are commercially exploited in the various marine communities. Data This dataset on the Atlantic herring (Clupea harengus) includes the metadata, sample weight, fish length, the sex and the number of specimens measured. This dataset covers the period of 1982 to present. In order to protect the confidentiality of the sources, some informations (such as those concerning the vessel) have been excluded and others (such as the date of capture) have been simplified. Entries where there was only one vessel in a fishing area for a given year were also excluded. Further information including the fishing areas coordinates can be found by clicking on the «Atlantic and Arctic commercial fisheries» and «Fishing areas» links below.

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.

Atlantic herring. Concentration, breeding areas and larval retention areas of Atlantic Herring in the St. Lawrence Estuary.Data extracted from the Fish Habitat Management Information System (FHAMIS). Concentration areas, spawning sites and breeding areas of Atlantic herring according to a literature review of documents produced between 1977 and 1998.

In 2015, a spawning ground acoustic survey that follows the design of the fishery-independent acoustic survey was initiated. This survey is the result of a partnership between DFO and fishery associations. The survey design uses random parallel transects within predefined strata. Surveys are conducted by fishermen in the fall fishing season according to protocols developed by DFO. The survey is conducted at night, during the weekend fishery closures except in Herring fishing area 16C and 16E in 2015 to 2017, where this region didn’t have weekend closures. The spawning ground acoustic survey is meant to provide a nightly estimate of spawning biomass among regions. It is analyzed in the same manner as the fishery-independent acoustic survey. The catches from the experimental nets are used to calibrate the spawning group specific target strength in order to obtain the nightly estimates of spawning biomass.

PURPOSE: The primary objective of this survey is to obtain an index of the abundance 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 as a random stratified survey and now employs a random selection of sampling sites within the study area. Sampling is completed annually over a 4-week period in July and August. 110 stations are sampled in Northumberland Strait in water depths exceeding 4 m at Lowest Normal Tide. The survey has employed a 286 rockhopper trawl in all years from 2001 to 2018, except in 2010 and 2011 when a Nephrops trawl was used. In 2019, a newly designed trawl (termed the “Northumberland trawl”) was used in addition to the rockhopper trawl. The Northumberland trawl is similar to the 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: Please contact the data custodians before attempting to use this information in support of any kind of scientific analyses.