Demographic Variation between Colour Patterns in a Temperate Protogynous Hermaphrodite, the Ballan Wrasse Labrus bergylta

Abstract

Fish populations are often treated as homogeneous units in typical fishery management, thereby tacitly ignoring potential intraspecific variation which can lead to imprecise management rules. However, intraspecific variation in life-history traits is widespread and related to a variety of factors. We investigated the comparative age-based demography of the two main colour patterns of Labrus bergylta (plain and spotted, which coexist in sympatry), a commercially valuable resource in the NE Atlantic. Individuals were aged based on otolith readings after validating the annual periodicity of annuli deposition. The relationships between the otolith weight and fish age and between otolith length and fish length were strong but differed between colour patterns. The fit of the growth models to the age and length data resulted in divergent growth curves between colour morphotypes and between sexes. Males and spotted individuals attained larger mean asymptotic sizes (Linf) than females and plain individuals, respectively, but converged to them more slowly (smaller k). Estimates of mortality based on catch curves from two independent datasets provided a global total mortality (Z) of 0.35 yr–1, although Z was larger in plain and female individuals. Overall, the results of this research have direct implications for management of L. bergylta and, as a precautionary measure, we recommend considering both colour patterns as two different management units.

Is the ballan wrasse (Labrus bergylta) two species? Genetic analysis reveals within-species divergence associated with plain and spotted morphotype frequencies

“…A previous study on spotty and plain morphotypes of ballan wrasse reported differences in growth trajectories, size at age, otolith length to body length, and mortality (Villegas-Ríos et al 2013b), and also in investment in reproduction versus growth (Villegas-Ríos 2013). Based upon those results, which included extensive growth and maturation analyses, it was concluded that there was likely to exist large genetic differences between these 2 morphotypes.…”

“…one is primarily spotty and the other primarily plain). If this is the case, then some of the observed differences in traits between the spotty and plain morphotypes as reported by Villegas-Ríos et al (2013b) may actually represent underestimates of the differences between the 2 genetic groups as there is no exact coincidence between morphotype and genetic grouping. Further studies using larger numbers of individuals and markers, and matching extensive life-history and trait data to the genetic data will be required to fully resolve this issue.…”

“…non-spotted; Fig. 1b) that are characterized by a uniform, although variable, body color (mainly greenish, brownish or reddish), darker in the back and whitish in the abdomen (Villegas-Ríos et al 2013b). In Galicia, where this has been investigated, both types display overlapping but, nevertheless, different life-history strategies, with plain morphs investing more in reproduction at the expense of growing less versus spotted morphs investing less in reproduction but growing bigger (Villegas-Ríos 2013).…”

The use of spearfishing competition data in fisheries management: evidence for a hidden near collapse of a coastal fish community of Galicia (NE Atlantic Ocean)

“…In general, most of the species were correctly identified, but in some cases, different species were pooled under the same morphotype designation; for example, annular sea bream Diplodus annularis (L.), white sea bream D. sargus (L.) and common two-banded sea bream D. vulgaris (Geoffroy Saint-Hilaire) were identified under the morphotype white sea bream, while in other cases the same species were identified as different morphotypes designation, for example ballan wrasse Labrus bergylta (Ascanius) was identified as two different morphotypes 'pintos' and 'maragotas' (see Villegas-R ıos et al 2013). The term species was used to refer to morphotype (Table 1).…”

Interannual fine‐scale site fidelity of male ballan wrasse Labrus bergylta revealed by photo‐identification and tagging

“…It inhabits rocky reefs and kelp beds at depths up to 60 m depth where it mostly feeds on small invertebrates (Figueiredo et al ., ). It's a long‐lived wrasse (≤ 30 years) with slow growth, although demographic parameters vary between the two main morphotypes that have been described: plain and spotted (Villegas‐Ríos et al ., ). As a protogynous hermaphrodite, all individuals are born females with sex change being very plastic (it occurs on average at 36 cm total length ( L T ) in plain morphotypes and 47.2 cm L T in spotted morphotypes).…”