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: To provide demographic parameters and relative indices of abundance for Atlantic herring in NAFO Division 4T. DESCRIPTION: The experimental gillnet survey is conducted in collaboration with Atlantic herring harvesters and uses standardized multi-mesh gillnets. Gillnets are set on spawning grounds in the spring and fall. Data (fish and sample) are collected to provide: (1) relative age-disaggregated indices of abundance, (2) an indicator of relative changes in fishery selectivity over time, and (3) information on the demographic composition of herring on the spawning grounds. PARAMETERS COLLECTED: Sample: sample location; sample weight; mesh size; length frequency Biological: length; weight; gonad weight; maturity stage (biological); sex (biological); ring count (biological) 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.

Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska (DY1706, EK60). The Midwater Assessment and Conservation Engineering (MACE) program of NOAA Fisheries, Alaska Fisheries Science Center (AFSC) conducted an acoustic-trawl (AT) stock assessment survey along the Gulf of Alaska (GOA) shelf and associated bays during the late spring and summer of 2017 to estimate the distribution and abundance of walleye pollock (Gadus chalcogrammus). The survey was conducted 8 June-16 August aboard NOAA Ship Oscar Dyson, a 64 meter stern trawler equipped with acoustic and oceanographic instrumentation. The primary instrument for the survey was a Simrad EK60 split-beam echosounder system utilizing five frequencies (18, 38, 70, 120, and 200 kHz). The vessel departed Kodiak, Alaska on 9 June and conducted the survey in three legs with all port calls in Kodiak; the project was completed with the arrival of the vessel in Kodiak on 16 August. Leg 1 of the project was conducted 9-28 June along the Gulf of Alaska (GOA) shelf from the Islands of Four Mountains to Outer Shumagin Trough (12-18, 20-21, 22, and 26-27 June). Leg 1 survey areas included Sanak Trough (19 June), Morzhovoi Bay (19-20 June), Pavlof Bay (21 June), Shumagin Islands area (23-25 and 26 June), and Mitrofania area (25 June); the vessel transited to Kodiak 27-28 June. The vessel departed Kodiak on 3 July to start leg 2 (3-28 July) and conducted survey work in Shelikof Strait (3-8 and 10 July), Nakchamik area (9 July), Alitak Bay (12-13 July), initial survey of Barnabas Trough (14-15 July), and GOA shelf (9-10, 10-12, and July). The vessel returned to Kodiak on 15 July, ending leg 2, due to mechanical issues and departed Kodak on 28 July to start leg 3. Leg 3 work included surveys of Chiniak Trough (28-29 July), Barnabas Trough (31 July-1 August), Marmot Bay (3-4 August), and completion of GOA shelf work (3 July; 2 and 4-14 August). The vessel transited to Kodiak Island (14-15 August) and ended the project in Kodiak on 16 August. Sphere calibrations of the echosounder system were conducted in Kalsin Bay, Kodiak Island, Alaska on 9 June and 16 August; no significant differences in gain parameters or transducer beam pattern characteristics were noted between the two calibrations.