Plasticity of European flounder life history patterns discloses alternatives to catadromy

Abstract

European flounder Platichthys flesus life history patterns were investigated in 3 basins along a latitudinal gradient (Minho, N Portugal; Gironde, SW France; Seine, N France). We used coupled Sr:Ca and Ba:Ca otolith signatures and microstructure to retrospectively determine habitats occupied by flounder during their life, including early larval ontogeny. Flounder exhibited high life history plasticity among and even within basins, apparent by the diversity of habitats used during larval ontogeny and throughout their lives, and by the age at which flounder migrated to freshwater. Egg signatures probably had a strong maternal influence, and our interpretation suggests that flounder spawned and/or hatched predominantly in brackish waters in the Minho, while in the Gironde and Seine, flounder spawned and/or hatched either in coastal, brackish or freshwater environments. The freshwater egg signature was most frequent in the Seine. These interpretations contradict the current general assumption that flounder spawn exclusively in coastal waters. During pre-metamorphosis and metamorphosis, flounder were predominantly in brackish waters in the Minho, while in the Gironde and Seine, they were mainly in coastal and freshwater environments, respectively. The diversity of flounder life histories (LH) (i.e. sequence of habitat residence: freshwater, brackish or coastal) after metamorphosis was similar between the Minho (LH = 13), Gironde (LH = 13) and Seine (LH = 14) basins. The age at which flounder migrated to freshwater also varied among sites, at an earlier age in the Minho and Gironde (< 0.5 yr old) than in the Seine, where flounder migrating from the coast into freshwater reached maximum frequencies at age 1.3 yr old. Thus, catadromy in European flounder may be facultative, and the factors influencing flounder high LH plasticity deserve thorough research.

Spawning Site Selection and Contingent Behavior in Common Snook, Centropomus undecimalis

“…Common Snook in these areas may spawn over a more restricted period than at the inlet site (i.e., only when salinities are high enough) or they may be able to spawn in a wider range of salinities than previously believed. Maternal environment has been shown to affect salinity thresholds needed for egg buoyancy in other species [68] and similar adaptability to variable salinity habitats has been exhibited by the European Flounder [63]. If these areas are spawning habitat, then spawning site selection by Common Snook may involve trade-offs between habitat with consistently high salinity, allowing for more reproductive events within a year, and habitat that is less predictable but provides greater refuge and/or feeding opportunities.…”

Life history of anadromous burbot (Lota lota, Linneaus) in the brackish Baltic Sea inferred from otolith microchemistry

“…This result is principally verified by Paragamian & Wakkinen (2008) who reported multiple burbot movement patterns in a river-lake system of North America, using telemetry and limited sample size. For example, Daverat et al (2012) have shown that European flounder Platichthys flesus may spawn in coastal, brackish or freshwater environments, and multiple habitat use patterns exist. For example, Daverat et al (2012) have shown that European flounder Platichthys flesus may spawn in coastal, brackish or freshwater environments, and multiple habitat use patterns exist.…”

“…This result is principally verified by Paragamian & Wakkinen (2008) who reported multiple burbot movement patterns in a river-lake system of North America, using telemetry and limited sample size. Although widespread in salmonids (e.g., Thorpe 1994), it is only recently when such examples amongst nonsalmonid fish have emerged (Daverat et al 2006(Daverat et al , 2012Feutry et al 2012). For example, Daverat et al (2012) have shown that European flounder Platichthys flesus may spawn in coastal, brackish or freshwater environments, and multiple habitat use patterns exist.…”

Juvenile nursery colonization patterns for the European flounder (Platichthys flesus): A latitudinal approach

“…All daily increment counts were made using a light microscope at 100× and 400× magnifications for the peripheral areas, and at 1000× magnification for the nucleus. Otolith microstructure was used to determine the duration of the different stages: pelagic (larval), metamorphosis (time period between first morphological asymmetry and the completion of juvenile features) and benthic (post-metamorphosis juveniles), in agreement with Geffen et al (2007) and Daverat et al (2012). The pelagic stage corresponded to the otolith nucleus, the metamorphic stage corresponded to the rings between the innermost and the outermost accessory primordia.…”