scholarly journals Fecundity of the Atlantic Mackerel (Scomber scombrus) in the Northwest Atlantic in 1987

1992 ◽  
Vol 12 ◽  
pp. 35-40 ◽  
Author(s):  
C A Griswold ◽  
M J Silverman
Keyword(s):  
Northwest Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus

Usefulness of Fourier Analysis of Otolith Shape for Atlantic Mackerel (Scomber scombrus) Stock Discrimination

1991 ◽  
Vol 48 (2) ◽  
pp. 296-302 ◽  
Author(s):  
Martin Castonguay ◽  
Patrick Simard ◽  
Pierre Gagnon
Keyword(s):  
Stock Structure ◽  
Discriminant Functions ◽  
Position Effects ◽  
Northwest Atlantic ◽  
Otolith Shape ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
The North ◽  
Stock Discrimination ◽  
The North Sea

We compared shapes of Atlantic mackerel (Scomber scombrus) sagittae between the two contingents (i.e. spawning groups) from the Northwest Atlantic and between the stocks from the Northwest Atlantic and the North Sea to evaluate whether otolith shape could differentiate between the two contingents in a mixed fishery. We quantified shapes with the Fourier series, an objective and rapid method which decomposes a shape's outline into a series of sinusoids. To determine a correct way to compare contingents/stocks, we first assessed four intracontingent effects on otolith shapes. Age and year-class effects were significant, while sex and bilateral position effects were not. This temporal instability in shapes indicates that confounding effects of age and year-class on otolith shapes need to be assessed carefully before drawing conclusions on stock structure. It also shows that comparative studies of otolith shapes with Fourier descriptors are not useful for mackerel contingent discrimination. The power of discriminant functions to correctly classify test mackerel samples separated by age and sampling year, on the basis of otolith shape, was better for comparisons between the stocks than for those between the contingents.

Harvesting Strategies and Fishing Mortality Reference Point Comparisons for the Northwest Atlantic Stock of Atlantic Mackerel (Scomber scombrus)

1993 ◽  
Vol 50 (8) ◽  
pp. 1749-1756 ◽  
Author(s):  
William J. Overholtz
Keyword(s):  
Population Level ◽  
Northwest Atlantic ◽  
Harvest Rate ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Predation Mortality ◽  
Fishing Strategies ◽  
Spawning Stock ◽  
Current Minimum

Previous research indicated that density dependence in population-level responses such as growth and predation mortality rate may play a major role in regulating the dynamics of the Northwest Atlantic stock of Atlantic mackerel (Scomber scombrus). Simulation studies, utilizing this compensatory model of the mackerel stock, suggest that expected yields and spawning stock sizes under conditions of constant harvest rate or constant catch would be quite disparate. Yields and spawning stock size would be less variable and slightly larger under a constant catch strategy for catches of mackerel up to approximately 200 000 t. However, a constant harvest rate strategy would provide higher long-term yields and a more stable spawning stock at catches greater than 200 000 t. A comparison of a constant catch policy with F0.1, F20, and Fmax fishing strategies (constant F) suggests that the Fmax and F20 strategies would cause a long-term decline in the spawning stock below the current minimum spawning stock target and provide highly variable yields. A constant catch strategy could produce nearly the same level of yield with considerably less variability and maintain a larger mean spawning stock biomass than the F0.1 strategy.

Long-Distance Migration of an Atlantic Mackerel (Scomber scombrus)

1974 ◽  
Vol 31 (9) ◽  
pp. 1521-1522 ◽  
Author(s):  
L. S. Parsons ◽  
J. A. Moores
Keyword(s):  
Long Island ◽  
Long Distance ◽  
Northwest Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus

The recapture south of Long Island of an Atlantic mackerel (Scomber scombrus) tagged in Newfoundland waters represents a migration of at least 2259.6 km (1400 miles), the farthest documented migration of mackerel ever reported from the Northwest Atlantic. This recapture supports earlier tagging evidence that overwinter mixing may occur between the northern and southern populations of mackerel.

scholarly journals Multi-decadal trends in contingent mixing of Atlantic mackerel (Scomber scombrus) in the Northwest Atlantic from otolith stable isotopes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kohma Arai ◽  
Martin Castonguay ◽  
David H. Secor
Keyword(s):  
Stable Isotopes ◽  
Stock Assessment ◽  
Northwest Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Stock Biomass ◽  
Oxygen Stable Isotopes ◽  
The Us ◽  
Spawning Stock ◽  
The Status

AbstractThe Atlantic mackerel (Scomber scombrus) in the Northwest Atlantic is comprised of northern and southern components that have distinct spawning sites off Canada (northern contingent) and the US (southern contingent), and seasonally overlap in US fished regions. Thus, assessment and management of this population can be sensitive to levels of mixing between contingents, which remain unknown. Multi-decadal trends in contingent mixing levels within the US fisheries region were assessed, and the contingent composition across seasons, locations, ages, and size classes were characterized using archived otoliths and developing a classification baseline based on juvenile otolith carbon and oxygen stable isotopes (δ13C/δ18O values). Classification of age ≥ 2 adults demonstrated that northern contingent mixing was prevalent within the US continental shelf waters during the past 2 decades (2000–2019), providing an important seasonal subsidy to the US winter fishery despite substantial depletion in spawning stock biomass of the dominant northern contingent. While the majority of older fish were of the northern contingent during the early 2000s, the southern contingent contribution increased with age/size class during the recent period (2013–2019). Spatial mixing was most prevalent during February and March when the northern contingent occurred as far south as the Delmarva Peninsula, but were mostly absent from US waters in May. A positive relationship (albeit not significant; r = 0.60, p = 0.07) occurred between northern contingent mixing and US fisheries landings, which could imply that higher contingent mixing levels might be associated with greater landings for the US winter mackerel fishery. The yield of the Northwest Atlantic mackerel depends upon the status of the northern contingent, with the southern contingent possibly more prone to depletion. Spatially explicit stock assessment models are recommended to conserve both productivity and stability in this two-component population.

scholarly journals Northwest Atlantic mackerel population structure evaluated using otolith δ18O composition

2020 ◽  
Author(s):  
S Gray Redding ◽  
L W Cooper ◽  
M Castonguay ◽  
C Wiernicki ◽  
D H Secor
Keyword(s):  
United States ◽  
Population Structure ◽  
The United States ◽  
Group Comparison ◽  
Northwest Atlantic ◽  
Atlantic Population ◽  
Atlantic Mackerel ◽  
Scomber Scombrus ◽  
Natal Origin ◽  
Spawning Site

Abstract The Northwest Atlantic mackerel (Scomber scombrus) population is comprised of northern and southern contingents, each with distinct natal regions in the United States and Canada. We tested hypotheses on natal origin and contingent mixing by analysing natal otolith δ18O values, evaluating the approach through an out-group comparison with the Northeast Atlantic population. Otolith δ18O values varied according to expectations between the Northeast (higher) and the Northwest (lower) Atlantic basins, and between contingents within the Northwest Atlantic stock, although contingent differences varied between years. Most adults (age-3+ years) sampled from US waters (1999–2003) represented the northern contingent (Canadian spawning site). The confirmation of the seasonal mixing of older and larger fish between the two contingents provides support and justification for the development of bi-national (United States–Canada) assessment and management of Northwest Atlantic mackerel.

Growth Comparison between Juvenile Atlantic Mackerel (Scomber scombrus) from the Two Spawning Groups of the Northwest Atlantic

1992 ◽  
Vol 49 (11) ◽  
pp. 2242-2248 ◽  
Author(s):  
Patrick Simard ◽  
Martin Castonguay ◽  
Denis D'Amours ◽  
Pierre Magnan
Keyword(s):  
Growth Curves ◽  
Gompertz Model ◽  
Growth Patterns ◽  
Ratio Test ◽  
Instantaneous Growth Rate ◽  
Otolith Microstructure ◽  
Daily Growth ◽  
Northwest Atlantic ◽  
Atlantic Mackerel ◽  
Scomber Scombrus

We compared daily growth patterns of otoliths of juvenile Atlantic mackerel (Scomber scombrus) younger than 91 d between the two spawning groups that occur in the Northwest Atlantic using a Gompertz model to determine whether it is possible to differentiate these groups on the basis of otolith microstructure in a mixed fishery. The growth curve parameters for the northern and southern groups, respectively, were 36.2 versus 39.7 d for the inflection point (t0), 0.047 versus 0.040 for the instantaneous growth rate (k) when t = t0, and 169.1 versus 192.5 mm for the asymptotic length at the end of the first summer of growth (L∞). These growth curves do not significantly differ (likelihood ratio test, P > 0.5). It therefore appears that the otolith microstructure corresponding to the first summer would not allow identification of the group of origin.

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