Research Document 2022/056
Demersal Juvenile Atlantic Cod (Gadus morhua) Survey of the Northeast Coast of Newfoundland: 2020 Fleming Survey
By Lewis, R.S., Ings, D.W., and Rogers, B.
Abstract
A survey of demersal juvenile Atlantic cod (Gadus morhua) was conducted along the Northeast Coast of Newfoundland in nearshore waters (<10 m deep) from 1959–64 by Government of Canada Departments (now represented by the Department of Fisheries and Oceans [DFO]). This survey (which became known as the Fleming survey, after originator Alistair Fleming) aimed to characterize the distribution and abundance of juvenile Atlantic cod and was based upon Norway’s Flødevigen sampling program which has been conducted continuously since 1919. A 25 m seine was used to sample juvenile Atlantic Cod nursery locations on the Avalon Peninsula and Northeast Coast of Newfoundland in September and October. The survey was discontinued in 1964 but was reinstated by Memorial University of Newfoundland from 1992–97. Multiple tows were conducted at a subset of the original 55 Fleming sites located in St. Mary’s Bay, Trepassey Bay, the Southern Shore, Conception Bay, Trinity Bay, Bonavista Bay, Gander Bay, New World Island, Fortune Harbour, Badger Bay, Halls Bay and Green Bay. A full version of the survey (40 sites) was executed in 2001 and select sites were surveyed in 2017 and 2018.
The Fleming survey program was reestablished by DFO in 2020. A total of 42 of the modern subset of 45 sites were visited resulting in 40 sites being sampled successfully in 2020. Direct comparison of Atlantic cod catch (count, lengths and rate) is possible across the time series because of consistency with survey methods. The primary objective was to collect data to determine abundance of age 0-, 1-, and 2- group cod to compare with previous surveys and reestablish a network of inshore harvesters (active and retired) to participate in the survey.
A total of 665 juvenile cod (615 0-group; 47 1-group, 3 2-group) were collected at 40 sites between St. Mary’s Bay and western Notre Dame Bay. The catch of 0-group cod dominates the overall catch (mean=15.38 cod/tow). In general, the mean juvenile cod catch for each group is similar to the mean catches from the 1990s and latter part of the 1959–64 time series. During the 2020 survey, only one tow was made per site to measure juvenile cod density due to logistical constraints. In earlier Fleming survey programs, multiple tows were conducted (minimum two) at a survey site in an attempt to develop a density index. In 2020, the average catch rate for 0-, 1-, and 2-groups was 15.38, 1.18, and 0.08 cod per haul respectively. These rates are generally consistent with the average cod per tow (first tow only) reported from the Fleming survey in the post collapse era (1992–97, and 2001): 13.35, 5.90, and 0.56 cod per tow for 0-, 1- and 2- groups. Densities of juvenile cod have not recovered since the stock collapse in the early-1990s, despite some improvements in adult population size.
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