DOI: 10.5061/dryad.w6m905r2r
title: Northern cod spawning sites in 2015

description: A decade ago, in 2015, a paper in this journal heralded the “comeback” of
 Canada’s iconic Northern cod some 25 years after its collapse in the early
 1990s. In this paper, the stock status determined by current and past
 models and recent management is reviewed, 10 years later. Summarily,
 surplus production and growth have stalled, some years being negative,
 although the stall point biomass is controversial (and well below
 historical norms). Structural equation models indicate the main correlate
 of production is spawning stock biomass (positive), whose correlates are
 abundances of capelin (Mallotus villosus) (positive) and harp seals
 (Pagophilus groenlandicus) (negative), with net production (enabling SSB
 growth) further reduced by fisheries. Reductions in the SSB thought
 necessary to avoid impairing recruitment, from 1.3 to 0.25 million t, have
 led to increases in harvest allocations and reopened commercial Canadian
 and foreign fisheries, despite advice by the Department of Fisheries and
 Oceans and independent science to keep removals low. Management objectives
 are opaque; if rebuilding, then SSB growth must remain the main objective,
 otherwise the Northern cod will be restrained to a shadow of its
 historical abundance and socio-economic and cultural importance.
description: # Northern cod spawning sites in 2015 Dataset DOI:
 [10.5061/dryad.w6m905r2r](https://doi.org/10.5061/dryad.w6m905r2r) ##
 Description of the data and file structure Spawning location data were
 collected from an acoustic-trawl survey of Northern cod (NAFO Divisions
 2J3KL) conducted in May 2015 from the research vessel "Celtic
 Explorer". The survey echosounder was a Kongsberg Simrad EK600 using
 Echoview software for analyses. The cod were caught in 15-minute fishing
 sets (or less if densities were high) using a Campelen 1800 research trawl
 directed by acoustic information. All sets containing female spawning cod
 were virtually 100% cod (no bycatch of other species). The complete survey
 track is included in the second file. The third file contains spawning
 timing data (Mean percent of adult female in spawning condition (hydrated
 eggs present) in bottom trawl sets (weighted by total catch) from
 acoustic-trawl surveys in winter (January and February), early spring
 (March and April), late spring (May and June), and fall (September) from
 1995 to 2015. Locations and numbers of female Northern cod in spawning
 condition (hydrated eggs) from acoustic-trawl survey in May 2015. Note
 that the Northern cod (NAFO Divisions 2J3KL) is currently rebuilding
 following stock collapse in the early 1990s. The Canadian Department of
 Fisheries and Oceans places it in the "cautious" zone of
 precautionary management - with ongoing commercial fisheries. ### Files
 and variables #### File:
 Ncod_2015_spawningF_distribution_setsGT5adF_1.xlsx
 **Description:** Spawning location data were collected from an
 acoustic-trawl survey conducted in May 2015 from the research vessel
 "Celtic Explorer". The survey echosounder was a Kongsberg Simrad
 EK600 using Echoview software for analyses. The cod caught in 15 minute
 fishing sets (or less if densities were high) using a Campelen 1800
 research trawl directed by the acoustic information. All sets containing
 female spawning cod were virtually 100% cod (no bycatch of other species).
 The complete survey track is included in the second file.The third file
 contains spawning timing data (Mean percent of adult female Northern cod
 (NAFO Divisions 2J3KL) in spawning condition (hydrated eggs present) in
 bottom trawl sets (weighted by total catch) from acoustic-trawl surveys in
 winter (January and February), early spring (March and April), late spring
 (May and June), and fall (September) from 1995 to 2015. ##### Variables *
 Trip: Cruise ID * Set: Set # * Num_adult_females: Number of adult females
 in set * Num_Females_Spawning: Number of females with hydrated eggs in set
 * Prop_Adult_Females_Spawning: Proportion of adult females with hydrated
 eggs * Lonneg: Longitude of set in degrees (decimal format, negative for
 West) * Latitude: Latitude of set in degrees (decimal format, positive for
 North) * year #### File: GPS_LON_LAT_25.xlsx **Description:** GPS fixes
 along acoustic-trawl survey track in May 2015 ##### Variables *
 GPS_sequential_number – Sequential identifier for each GPS fix. - GPS_date
 – Date of the GPS reading. * GPS_time – Time of the GPS reading in local
 Newfoundland time. - Lonneg – Longitude in decimal degrees (negative
 values indicate West). * Latitude – Latitude in decimal degrees (positive
 values indicate North). #### File: Spawning_timing.xlsx
 **Description:** Spawning timing of female Northern cod (pooled 1995-2015)
 by month group ##### Variables * Monthgroupname – The month group used for
 summarizing the data. - PropFspawning_weighted – Proportion of adult
 females with hydrated eggs, weighted by the number of adult females in
 each set. * Num_sets – The number of sets included in the month group. -
 SE – The standard error of the weighted proportion. * Num_matureF_sampled
 – The total number of mature females sampled in the month group. ##
 Code/software Excel of any free software that will read excel files (eg.
 Open Office)