Geographic variation of golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella) in the North Atlantic based on otolith shape analysis

Abstract

Geographic variation of golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella) in the North Atlantic based on otolith shape analysis Christoph Stransky Stransky, C. 2005. Geographic variation of golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella) in the North Atlantic based on otolith shape analysis. e ICES Journal of Marine Science, 62: 1691e1698.The unresolved interrelationships of North Atlantic redfish stocks have prevented adaptive fisheries assessment and management in the past. Otolith shapes of golden redfish (S. marinus) and deep-sea redfish (S. mentella) were analysed for geographic variation within the entire distribution range in the North Atlantic, in order to evaluate this technique for stock separation. Multivariate analysis of elliptical Fourier shape descriptors revealed high similarity of S. marinus within the central North Atlantic areas (West and East Greenland, Iceland) that were relatively well separated from the Flemish Cap and Barents Sea samples. A similar separation of the Barents Sea area was also observed for S. mentella, whereas the western (Flemish Cap, Davis Strait) and central areas were overlapping to a greater extent. The overall classification rate given by discriminant analysis was poor for both species ( !50%) but increased to 72e74% by combining sampling areas to regions (west, central, east). Geographic variation in otolith shapes of both redfish species suggests a separation of the Northeast Arctic stocks (Barents Sea) of both species from the other redfish stocks assessed within ICES and NAFO, whereas similarities observed for the highly migratory S. mentella give reason for integrated management of demersal and pelagic occurrences of this important fisheries resource that straddles the ICES/NAFO boundaries.

Ontogenetic and environmental effects on otolith shape variability in three Mediterranean European eel (Anguilla anguilla, L.) local stocks

“…The approach used in this study, useful in distinguishing between different stocks of many fish species (Torres et al, 2000;Cardinale et al, 2004;Stransky, 2005;Petursdottir et al, 2006), has proven to be reliable also in differentiating local eel stocks, that belong to a single, spatially homogeneous stock insofar as the European eel is a panmittic species Palm et al, 2009). Our results highlight the role of environmental factors and not only genetic factors in determining the size and shape of fish otoliths.…”

Environmental and genetic determinant of otolith shape revealed by a non-indigenous tropical fish

“…However, some morphometric differences between fish reared in rivers as opposed to open water environments appear to have a genetic basis (Cadrin 2000). Otolith shape does not necessarily reflect genetic differences (Stransky 2005). Otoliths present variations among conspecific individuals and numerous confounding effects have been pointed out: sex, body condition, age, year class, stock (Castonguay et al 1991, Begg & Brown 2000, Monteiro et al 2005, as well as different local environmental conditions or factors such as food availability, depth, water temperature and substrate type (Lombarte & Lleonart 1993, Begg et al 2001, Gagliano & McCormick 2004, Mérigot et al 2007, Burke et al 2008, Hüssy 2008, Schulz-Mirbach et al 2008.…”

Otolith shape and size: The importance of age when determining indices for fish-stock separation

“…Expert otolith readers have drawn on otoliths to discriminate between: different ages or cohorts Burke et al 2009); sex (Cardinale et al 2004); diet (Gagliano and McCormick 2004) and of course stock (Begg and Brown 2000;Begg et al 2001;Brophy and Danilowicz 2002;Mérigot et al 2007;Duarte-Neto et al 2008). Some of these distinctions are more complex and more important to fisheries management (Begg et al 2005), which requires accurate measurements of stock composition/mixing, or stock movement, to inform decision making (Stransky 2005).…”

“…Paul et al 2013;Keating et al 2014). In some cases these measurements are supplemented with, or normalised by, measures such as fish length or weight (DeVries et al 2002;Stransky 2005;Mérigot et al 2007). Otolith boundaries are also extracted and represented, or encoded in different ways (transformed) prior to analysis with methods such as Fourier transforms (Begg and Brown 2000;Galley et al 2006;Bani et al 2013); and Elliptical Fourier transforms (Campana and Casselman 1993;Duarte-Neto et al 2008).…”