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

Abstract

Otolith morphometrics have been shown to provide a practical basis for stock discrimination and subsequent fisheries management. However, the determinants of otolith shape are not fully understood and analysis does not distinguish between genotype and environmentally induced differences. In this context, understanding how those 2 components act synergetically on the otolith shape is fundamental. The use of non-indigenous fish of multiple origins provides an interesting tool for evaluating the relative importance of genetic and environmental components in determining otolith shape. This paper investigates to what extent a dual regulation (i.e. genetic and environmental) of the otolith shape from an introduced coral reef snapper (Lutjanus kasmira) exists, in order to determine how each component specifically acts on otolith morphology. Using geometric morphometrics, we discriminated between native and introduced range as well as between individuals belonging to different lineages (i.e. origins) but growing under the same environmental conditions (individuals cohabiting within the same shoals in the wild). Here we show that both genetic and environmental influences play a substantial role in determining the shape of the otolith. More specifically, while environment induces an overall change in otolith shape, genetically induced changes locally affect otolith shape. In addition, data suggest that both nuclear and mitochondrial components act synergetically. This information is fundamental if otolith shape is to be used as an effective tool for management of fisheries resources in the future. KEY WORDS: Fisheries management · Stocks · Geometric morphometrics · Lutjinidae · French Polynesia · Hawaiian archipelago · Evolutionary Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 411: [231][232][233][234][235][236][237][238][239][240][241] 2010 (Cadrin 2000, Begg et al. 2005, Campana 2005 because it provides a practical basis for stock separation that is useful in fisheries management (Begg & Waldman 1999).It is currently recognised that otolith growth and shape occurs under dual regulation: overall shape is regulated genetically, but there is a strong variability related to environmental factors. A number of authors have suggested that otolith shape is genetically constrained, species specific and reflects phylogenetic relationships (Lombarte & Castellón 1991, Lombarte & Lleonart 1993, Reichenbacher et al. 2009). However, otoliths present variation among conspecific individuals, being mainly influenced by sex, age, year class and stock (Castonguay et al. 1991, Begg & Brown 2000, Monteiro et al. 2005 as well as by local environmental conditions or factors such as depth, water temperature and substrate type (Lombarte & Lleonart 1993, Gagliano & McCormick 2004, Mérigot et al. 2007, Hüssy 2008. Although several studies have indicated that otolith shape differences between stocks are likely to be caused by both environmental and genetic influences, it is unclear to ...

Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)

“…The relationship between fish size and otolith shape reflects the combined effects of ontogeny and the environment on otolith shape (Vignon 2012). The overall species-specific shape of the otolith and the nature of its development during ontogeny from the circular larval otolith to the more complex morphology of the adult otolith is genetically determined (Hüssy 2008;Reichenbacher et al 2009;Vignon and Morat 2010), with exogenous factors having a modulating effect through, for example, the effects of feeding and growth on the nature of crystal formation (Gauldie and Nelson 1990) and the rate of protein accretion in the otolith (Hüssy 2008). The shape of the otolith may also reflect its physiological function in hearing and balance, and such variation can have an adaptive significance.…”

“…Otolith shape is known to vary both between and within species (Lombarte and Castellon 1991) because of the combined effects of genetic and environmental factors (Vignon and Morat 2010). Fish with different life histories show variation in otolith shape (Vignon and Morat 2010), thus otolith shape measurements can be used to discriminate between stocks.…”

“…Fish with different life histories show variation in otolith shape (Vignon and Morat 2010), thus otolith shape measurements can be used to discriminate between stocks. Thanks to advances in image analysis, variation in otolith shape is now readily captured using geometric measurement of digitised otolith outlines (Stransky 2014).…”

Inter-population differences in otolith morphology are genetically encoded in the killifish <i>Aphanius fasciatus</i> (Cyprinodontiformes)

“…Campana 1999, Volpedo and Cirelli 2006, Woods et al 2010. However, only a few studies have addressed the question whether inter-population differences in otolith traits are genetically encoded or the result of differences in certain habitat parameters (Torres et al 2000, Stransky et al 2008, Lombarte et al 2010, Vignon and Morat 2010.…”

Testing otolith morphology for measuring marine fish biodiversity

“…The use of otoliths for geometric morphometric analysis was initially questioned because otoliths have limited points with biologically homologous characteristics or landmarks (Rohlf and Marcus 1993). However, more recent studies have demonstrated the suitability of this approach (Monteiro et al 2005;Ponton 2006;Lombarte et al 2010;Vignon and Morat 2010).…”