Otolith Types Research Articles

Identification of Konosirus punctatus (Temminic and Schlegel, 1846) stocks in Korean waters via otolith shape analysis and comparison of growth parameters

Accurate identification of fish stocks is essential for the successful management of fishery resources. In this study, the populations of dotted gizzard shad, Konosirus punctatus, which is listed on the International Union for Conservation of Nature red list of the threatened species, were identified by combining two phenotypic methods: otolith shape analysis and comparison of growth parameters. Otolith shape analysis revealed two types of otoliths, pointing to the presence of two gizzard shad stocks in two areas along the Korean coast: the East Sea and the Yellow Sea + western Korean Strait. It is also supported by the result that the two stocks are significantly different in the shape indices (SI), and asymptotic fork length (FL∞). These results may be due to the influence of several environmental factors, such as temperature, salinity, and food availability. Overall, our findings suggest that there are two phenotypic stocks of K. punctatus in the Korean coastal waters and they should be managed differently.

Staining protocols affect use of otolith to estimate the demography of the damselfish sergeant major (Abudefduf vaigiensis).

This study assessed the otolith (sagittae, lapilli, and asterisci) increment deposition rate in the range-shifting damselfish, A. vaigiensis, using different concentrations of Alizain Red S and evaluated the impact of staining on increment width. Daily increment deposition was verified in all otolith types and presented clearer fluorescent markings in the lapilli and sagittae than the asterisci, with high stain concentration showing the best clarity. Higher stain concentrations were found to decrease increment width, suggesting care is needed when using stained otoliths as a proxy for growth for this species.

Biological Features of Atlantic Cod <i>Gadus Morhua</i> L., 1758 (Gadiformes: Gadidae) of the Murmansk Coast: Race Composition and Fishing

The biological features of Atlantic cod in the coastal zones of the Murman for 1999–2006 were studied. The age composition, growth rate and maturation, feeding habits and structure of otoliths were analyzed. Histological and genetic studies were carried out. It was shown that young cod mainly lives and spawns in Western Murman bays. Older cod leaves the bays due to insufficient food supply. The growth rate of young coastal cod is comparable to that of cod in the open part of the Barents Sea. With age, the cod of open sea areas noticeably overtakes the cod that lives in the coastal zone in growth. It was noted that cod spawns in the bays with both coastal and Atlantic types of otoliths. Studies of genetic polymorphism indicate a high degree of genetic si-milarity between cod groups in the Norwegian and Barents Seas, which is evidenced under the influence of currents (branches of the Norwegian Atlantic Current, the Murmansk Coastal Current) and against the background of migrations at different stages of ontogeny of cod individuals from coastal and open water areas.

Morphological and morphometric features of the abnormal and normal saccular otoliths in flatfishes.

The fish's inner ear consists of three interconnected semicircular canals and otolith organs located in these canals, which are responsible for balance and hearing. Abnormalities in these organs can affect the vital activities of the fish. The main purpose of this study was to determine the morphological and morphometric characteristics of abnormal and normal sagittal otoliths in the four flatfish species (Lepidorhombus boscii, Platichthys flesus, Solea solea, and Pegusa lascaris) sampled from three seas (Aegean Sea, Mediterranean Sea, and Black Sea). Abnormalities in otoliths are investigated using light microscopy, scanning electron microscopy, and Raman spectroscopy. The otolith morphometric measurements and morphology are recorded for abnormal and normal otoliths for each species. It was determined that the four flatfish species examined in the present study showed differences in the morphological features of normal and abnormal otoliths in the blind and eyed sides. In addition, statistical differences were observed when the weight, length, width, perimeter, and area values of normal and abnormal otoliths of all species were compared (p < .05). The four types of saccular otoliths were defined, one normal (type 0) and three abnormal (type 1, type 2, and type 4) for four flatfish species. The current study presents for the first-time abnormal otolith morphology information on blind and eyed side sagittal otoliths in these flatfish species. Abnormalities in the anatomical structures of bony parts such as otoliths in fish may be caused by pollution, nutritional problems, stress, and environmental factors as well as a combination of these.

Inter-Otolith Differences in Strontium Markings: A Case Study on the Juvenile Crucian Carp Carassius carassius (Linnaeus, 1758)

The release of hatchery-reared fish fry for restocking is important for the enrichment of fishery resources; however, the effective evaluation of the success rate of marking such fish is challenging. We exposed juvenile crucian carp (Carassius carassius) to a single concentration of SrCl2·6H2O for 5 d and evaluated the efficiency of Sr marking of the fish otoliths (sagittae, asterisci, and lapilli) using an electron probe micro-analyzer. Sr marking signatures formed a peak in all otolith types, with a marking success rate of 100%. The ratio of Sr to Ca in the lapilli and sagittae was higher than that in the asterisci. It took 2 d from the beginning of immersion to the deposition of Sr on the lapilli and sagittae, and the time delay for asterisci was 1 d. For the lapilli and sagittae, it took 16 d to terminate Sr marking and fully recover to the pre-marking Sr level, whereas it was 12 d for the asterisci. The application of the Sr dose had no effect on the survival or growth of the carp. This study demonstrated that the lapilli are the most suitable otolith type for Sr marking observations in crucian carp and provides a theoretical basis and technical support for carp restocking using the Sr marking approach.

Age and growth in different stocks of striped snakehead Channa striata (Bloch, 1793) inhabiting the three rivers of Gangetic river system

Age was estimated using different types of otoliths (sagittae, lapilli and asterisci) collected from 486 specimens of Channa striata (Bloch, 1793) from three Indian rivers, the Ganga, Gomti and Yamuna, during the period November 2012 - August 2015. The size range of the specimens was 15-70 cm total length (TL). The age estimates were compared and assessed for potential bias between readers and between pairs of aging structures. Due to the highest percentage of agreement and lowest average percentage of error and coefficient of variation values between readers, sagittae were found to be the most suitable aging structure for C. striata. When sagittae age reading were compared with those from lapilli and asterisci, the percentage of agreement was found to be highest between estimates of sagittae and lapilli. Mean values of age estimate from sagittae were comparable (p&gt;0.05) to the values obtained from lapilli but significantly (p&lt;0.05) different with that of asterisci. Thus, sagittae emerged as the preferred otolith for age estimation in C. striata followed by lapilli. The growth of C. striata was assessed by examining annual growth increments on sectioned sagittae. The parameters of von Bertalanffy growth equations for the fish in the selected rivers were: Lt = 94.4 (1-e-0.15(t+1.07)) for river Ganga, Lt = 93.7 (1-e-0.15(t+0.96)) for river Yamuna and Lt = 96.9 (1-e-0.14(t+1.02)) for river Gomti. The growth performance index was highest in fish stocks collected from river Ganga (3.13) followed by river Gomti (2.96) and river Yamuna (2.38). Marginal increment analysis suggested annual periodicity of the growth band formation.Keywords: Ageing precision, Channa striata, Marginal increment analysis, Otoliths, VBGF

Possible link between the structure of otoliths and amphibious mode of life of three mudskipper species (Teleostei: Gobioidei) from the Persian Gulf

The otoliths of three mudskipper species from the Persian Gulf that are characterised by different degrees of amphibious adaptation were examined using SEM imaging and otolith morphometry. Scartelaos tenuis, which is the most aquatic of the three species, has rhomboid to rectangular otoliths that conform to the general otolith type of many marine gobiid species. The otoliths of Periophthalmus waltoni, which is one of the most amphibious mudskipper species, are pentagonal-shaped and deviate from the usual otolith type of the Gobiidae by the absence of a posterodorsal projection and deep ostial lobes. Boleophthalmus dussumieri is intermediate with respect to its amphibious adaptation between S. tenuis and P. waltoni, and the shape of its otoliths is intermediate between the otoliths of those two species. Otolith morphometry related to sulcus measurements more clearly separated P. waltoni from B. dussumieri, than S. tenuis from either P. waltoni or B. dussumieri. As P. waltoni and B. dussumieri can occur syntopically and display similar behaviours, the morphometric disparity of their sulcus proportions might be related to efficient intraspecific communication among neighbouring species.

Marking Otoliths of Alligator Gar by Immersion in Oxytetracycline

AbstractAlligator Gar Atractosteus spatula are increasingly being stocked to restore populations, making the need to identify stocked individuals important for monitoring. Oxytetracycline (OTC) immersion allows for large numbers of fish to be marked simultaneously, thus eliminating the need to handle fish individually, but protocols for doing so have not been investigated fully for this species. In this study, we sought to identify dosages of OTC (concentration and duration of exposure) that would successfully mark juvenile Alligator Gar while minimizing mortality as a result of the marking procedures. Juvenile Alligator Gar (38 ± 4.4 mm [mean ± SE]) were collected from raceways at Tishomingo National Fish Hatchery 18–22 d after hatch and were marked during transport to the Oklahoma Fishery Research Laboratory. Ten individuals per treatment (360 total individuals) were randomly placed into one of three replicates containing one of four concentration × duration combinations of Pennox 343 OTC solution. Juvenile Alligator Gar were exposed to an OTC concentration of 0 (control), 500, 600, or 700 mg/L for a duration of 4, 5, or 6 h. Asteriscus, lapillus, and sagittal otoliths were examined for mark presence at 14 d postexposure by using fluorescent microscopy. The OTC concentration and duration both affected mean mark quality similarly among otolith types. Mortality increased with increasing OTC concentration, suggesting that a balance between concentration and duration is needed to achieve marking goals. Based on our findings, batch marking of Alligator Gar was successful at OTC concentrations from 500 to 700 mg/L for 4–6 h, although immersion at 500 mg/L for 6 h and 600 mg/L for 4–6 h produced the best balance between high mark quality and low associated mortality.

In vivo and in vitro analysis of starmaker activity in zebrafish otolith biomineralization.

Otoliths are one of the biominerals whose formation is highly controlled by proteins. The first protein discovered to be involved in otolith biomineralization in zebrafish was starmaker (Stm). Previously, Stm was shown to be responsible for the preferential formation of aragonite, a polymorph of calcium carbonate, in otoliths. In this work, proteomic analysis of adult zebrafish otoliths was performed. Stm is the only highly phosphorylated protein found in our studies. Besides previously studied otolith proteins, we discovered several dozens of unknown proteins that reveal the likely mechanism of biomineralization. A comparison of aragonite and vaterite otoliths showed similarities in protein composition. We observed the presence of Stm in both types of otoliths. In vitro studies of 2 characteristic Stm fragments indicated that the DS-rich region has a special biomineralization activity, especially after phosphorylation.-Kalka, M., Markiewicz, N., Ptak, M., Sone, E. D., Ożyhar, A., Dobryszycki, P., Wojtas, M. In vivo and in vitro analysis of starmaker activity in zebrafish otolith biomineralization.

Otoliths in situ in the stem teleost Cavenderichthys talbragarensis (Woodward, 1895), otoliths in coprolites, and isolated otoliths from the Upper Jurassic of Talbragar, New South Wales, Australia

ABSTRACTCavenderichthys talbragarensis (Woodward, 1895) is a common signature freshwater stem teleost in the Upper Jurassic of Australia. Our discovery of numerous otoliths in the Talbragar Fish Bed establishes Cavenderichthys as only the second known Jurassic teleost and the third known stem teleost with otoliths in situ and provides an important calibration point for the interpretation of isolated Mesozoic otoliths. It corroborates the low degree of morphological diversification of stem teleost otoliths. The abundance of otoliths (isolated, in coprolites and in situ) allows the mapping of ontogenetic effects and of intraspecific variability for the first time in attributable stem teleost otoliths. Here, we describe 284 otoliths, mostly from Cavenderichthys. Otoliths in situ in Cavenderichthys document the presence of sagitta, lapillus, and asteriscus. Three other, much rarer otolith types were also found that have a teleost otolith pattern more primitive than that of Leptolepidiformes; the origin of these is unknown, but it is likely that they stem from pholidophoriform fishes of the family Archaeomenidae. If confirmed, this otolith pattern would provide a further highly diagnostic and synapomorphic character to define teleosts at the level of the Leptolepidiformes and above. Different mineral replacement processes in fossils from the Talbragar Fish Bed aided us in finding many otoliths, particularly otoliths in situ. Given their abundance and distinct preservation, it is surprising that otoliths in the Talbragar Fish Bed have not been recognized before.

Enigmatic ear stones: what we know about the functional role and evolution of fish otoliths.

Otoliths in bony fishes play an important role in the senses of balance and hearing. Otolith mass and shape are, among others, likely to be decisive factors influencing otolith motion and thus ear functioning. Yet our knowledge of how exactly these factors influence otolith motion is incomplete. In addition, experimental studies directly investigating the function of otoliths in the inner ear are scarce and yield partly conflicting results. Herein, we discuss questions and hypotheses on how otolith mass and shape, and the relationship between the sensory epithelium and overlying otolith, influence otolith motion. We discuss (i) the state-of-the-art knowledge regarding otolith function, (ii) gaps in knowledge that remain to be filled, and (iii) future approaches that may improve our understanding of the role of otoliths in ear functioning. We further link these functional questions to the evolution of solid teleost otoliths instead of numerous tiny otoconia as found in most other vertebrates. Until now, the selective forces and/or constraints driving the evolution of solid calcareous otoliths and their diversity in shape in teleosts are largely unknown. Based on a data set on the structure of otoliths and otoconia in more than 160 species covering the main vertebrate groups, we present a hypothetical framework for teleost otolith evolution. We suggest that the advent of solid otoliths may have initially been a selectively neutral 'by-product' of other key innovations during teleost evolution. The teleost-specific genome duplication event may have paved the way for diversification in otolith shape. Otolith shapes may have evolved along with the considerable diversity of, and improvements in, auditory abilities in teleost fishes. However, phenotypic plasticity may also play an important role in the creation of different otolith types, and different portions of the otolith may show different degrees of phenotypic plasticity. Future studies should thus adopt a phylogenetic perspective and apply comparative and methodologically integrative approaches, including fossil otoliths, when investigating otoconia/otolith evolution and their function in the inner ear.

Otolith Marking of Juvenile Shortnose Gar by Immersion in Oxytetracycline

AbstractOxytetracycline (OTC) has been used to mark a variety of fish species at multiple developmental stages; however, there is little information on batch‐marking Lepisosteidae. Juvenile Shortnose Gar Lepisosteus platostomus (53 ± 3 mm TL) were seined from an Oklahoma State University research pond and transported to the Oklahoma Fishery Research Lab. Juvenile Shortnose Gar were exposed to a range of OTC concentrations—0, 500, 600, and 700 mg/L—for 4, 5, or 6 h. Lapillus and sagitta otoliths were examined 14 d postexposure for mark presence and evaluation using fluorescent microscopy. Overall, 93.3% of otoliths exposed to OTC exhibited a mark. Concentration of OTC affected the mean mark quality, whereas duration and otolith type examined did not. However, as concentration increased, so did mortality, suggesting a balance is needed to achieve marking goals. Based on our findings, batch marking of Shortnose Gar can be successful at OTC concentrations from 500 to 700 mg/L for 4–6 h, although mark quality may vary and mortality rates increase at the higher concentrations and longer durations.Received November 28, 2016; accepted April 4, 2017 Published online June 6, 2017

Corrigendum to: All good things come in threes – species delimitation through shape analysis of saccular, lagenar and utricular otoliths

Otoliths are calcium carbonate biomineralisates in the inner ear of teleost fishes. Otoliths of the saccule (sagittae) are known to show species-specific (or even population-specific) contour differences and, thus, are regularly used in fisheries management for stock identification. However, the other two otolith types from the utricle (lapilli) and lagena (asterisci) are typically neglected in studies of this kind, such that little information is available regarding potential species-specific contour differences. Using four species of livebearing fishes of the genus Poecilia (Cyprinodontiformes, Poeciliidae), we compared contour outlines of all three otolith types by applying Fourier shape analysis and tested for species delimitation success of the different otolith types alone, and all three otoliths combined. Our results indicated that also lapilli and especially asterisci convey species-specific information, and the classification success of discriminant function analyses was highest when combining shape information from all three otolith types. We propose that future studies on species delimitation or stock identification may benefit from considering all three otolith types together.

Comparative study of carp otolith hardness: Lapillus and asteriscus

Otoliths are calcium carbonate biominerals in the inner ear of vertebrates; they play a role in balance, movement, and sound perception. Two types of otoliths in freshwater carp are investigated using nano- and micro-indentation: asteriscus and lapillus. The hardness, modulus, and creep of asteriscus (vaterite crystals) and lapillus (aragonite crystals) are compared. The hardness and modulus of lapillus are higher than those of asteriscus both in nano- and micro-testing, which is attributed to the different crystal polymorphs. Both materials exhibit a certain degree of creep, which indicates some time dependence of the mechanical behavior and is attributed to the organic components. The nano-indentation hardnesses are higher than micro-hardnesses for both otoliths, a direct result of the scale dependence of strength; fewer flaws are encountered by the nano than by the microindenter.

Asteriscus v. lapillus: comparing the chemistry of two otolith types and their ability to delineate riverine populations of common carp Cyprinus carpio

The chemical composition of common carp Cyprinus carpio asteriscus (vaterite) and lapillus (aragonite) otoliths from the same individual and reflecting the same growth period was measured to (1) determine whether there are differences in the uptake of trace metals (Mg:Ca, Mn:Ca, Sr:Ca and Ba:Ca ) and Sr isotope ratios ((87)Sr:(86)Sr) in co-precipitating lapilli and asterisci and (2) compare the ability of multi-element and isotopic signatures from lapilli, asterisci and both otolith types combined to discriminate C. carpio populations over a large spatial scale within a river basin. Depth profile analyses at the otolith edge using laser-ablation inductively coupled plasma mass spectrometry showed that asterisci were enriched in Mg and Mn and depleted in Sr and Ba relative to lapilli, whilst (87)Sr:(86)Sr values were nearly identical in both otolith types. Significant spatial differences among capture locations were found when all trace element and Sr isotope ratio data were aggregated into a multi-element and isotopic signature, regardless of which otolith type was used or if they were used in combination. Discriminatory power was enhanced, however, when data for both otolith types were combined, suggesting that analysis of multiple otolith types may be useful for studies attempting to delineate C. carpio populations at finer spatial or temporal scales.

All good things come in threes – species delimitation through shape analysis of saccular, lagenar and utricular otoliths

Otoliths are calcium carbonate biomineralisates in the inner ear of teleost fishes. Otoliths of the saccule (sagittae) are known to show species-specific (or even population-specific) contour differences and, thus, are regularly used in fisheries management for stock identification. However, the other two otolith types from the utricle (lapilli) and lagena (asterisci) are typically neglected in studies of this kind, such that little information is available regarding potential species-specific contour differences. Using four species of livebearing fishes of the genus Poecilia (Cyprinodontiformes, Poeciliidae), we compared contour outlines of all three otolith types by applying Fourier shape analysis and tested for species delimitation success of the different otolith types alone, and all three otoliths combined. Our results indicated that also lapilli and especially asterisci convey species-specific information, and the classification success of discriminant function analyses was highest when combining shape information from all three otolith types. We propose that future studies on species delimitation or stock identification may benefit from considering all three otolith types together.

Effects of extreme habitat conditions on otolith morphology – a case study on extremophile livebearing fishes ( Poecilia mexicana, P. sulphuraria)

Our study was designed to evaluate if, and to what extent, restrictive environmental conditions affect otolith morphology. As a model, we chose two extremophile livebearing fishes: (i) Poecilia mexicana, a widespread species in various Mexican freshwater habitats, with locally adapted populations thriving in habitats characterized by the presence of one (or both) of the natural stressors hydrogen sulphide and darkness, and (ii) the closely related Poecilia sulphuraria living in a highly sulphidic habitat (Baños del Azufre). All three otolith types (lapilli, sagittae, and asterisci) of P. mexicana showed a decrease in size ranging from the non-sulphidic cave habitat (Cueva Luna Azufre), to non-sulphidic surface habitats, to the sulphidic cave (Cueva del Azufre), to sulphidic surface habitats (El Azufre), to P. sulphuraria. Although we found a distinct differentiation between ecotypes with respect to their otolith morphology, no clear-cut pattern of trait evolution along the two ecological gradients was discernible. Otoliths from extremophiles captured in the wild revealed only slight similarities to aberrant otoliths found in captive-bred fish. We therefore hypothesize that extremophile fishes have developed coping mechanisms enabling them to avoid aberrant otolith growth – an otherwise common phenomenon in fishes reared under stressful conditions.

Geographic variation in otolith morphology among freshwater populations of Aphanius dispar (Teleostei, Cyprinodontiformes) from the southeastern Arabian Peninsula

Aphanius Nardo is a large genus of teleost fishes in the Old World, with 19 described species. Several of these species have only recently been recognized and additional species can be expected from isolated populations in remote areas. We show here that otolith morphology and statistical analyses of otolith variables can contribute to the detection of genetic differentiation in Aphanius. We studied samples of eight Aphanius dispar populations from the southeastern part of the Arabian Peninsula. Two populations originate from freshwater habitats far inland and probably have been isolated since the late Holocene some 4,000 years ago, three populations come from freshwater habitats with occasional connections to the sea, one population originates from a coastal site, and two were artificially introduced populations. The coastal population is interpreted as possessing the basic otolith type of A. dispar. The basic otolith type also occurs in fishes from the freshwater habitat which is located closest to the coast. Otoliths from the two other freshwater populations with occasional connections to the coast differ slightly from the basic type. However, the two populations from the long-term isolated freshwater habitats far inland show distinct morphological changes. Our results are consistent with the hypotheses that i) otolith morphology is primarily genetically determined and is little influenced by physical parameters of the habitat, and ii) isolated A. dispar populations may be capable of evolving into new species within short periods of time.

Sparc Protein Is Required for Normal Growth of Zebrafish Otoliths

Otoliths and the homologous otoconia in the inner ear are essential for balance. Their morphogenesis is less understood than that of other biominerals, such as bone, and only a small number of their constituent proteins have been characterized. As a novel approach to identify unknown otolith proteins, we employed shotgun proteomics to analyze crude extracts from trout and catfish otoliths. We found three proteins that had not been associated previously with otolith or otoconia formation: 'Secreted acidic cysteine rich glycoprotein' (Sparc), an important bone protein that binds collagen and Ca(2+); precerebellin-like protein, which contains a C1q domain and may associate with the collagenous otolin-1 during its assembly into a framework; and neuroserpin, a serine protease inhibitor that may regulate local protease activity during framework assembly. We then used the zebrafish to investigate whether Sparc plays a role in otolith morphogenesis. Immunodetection demonstrated that Sparc is a true constituent of otoliths. Knockdown of Sparc expression in morphant zebrafish resulted in four principal types of defective otoliths: smaller, extra and ectopic, missing and fused, or completely absent. Smaller size was the predominant phenotype and independent of the severity of otic-vesicle defects. These results suggested that Sparc is directly required for normal otolith growth.

The differentiation of Stegastes partitus populations using lapillar and sagittal otolith chemistry

The comparison of elemental concentrations of sagittal and lapillar otoliths from the same individuals of Stegastes partitus indicated significant differences for several elements. Sagittal otoliths were superior at differentiating individuals, yet the differentiation of individuals was further improved when the elemental concentrations of both otolith types were used in the same analysis.