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This study examined the relationship between otolith size and growth in juvenile cod (Gadus morhua L). Two groups of juvenile cod were reared under different food ration and temperature regimes to obtain fish of similar somatic si...
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This study examined the relationship between otolith size and growth in juvenile cod (Gadus morhua L). Two groups of juvenile cod were reared under different food ration and temperature regimes to obtain fish of similar somatic size but with different sized otoliths. The two groups were subjected to alternating temperature regimes and intermediate ration levels. Large otoliths grew significantly faster than the small ones and variation between individuals was extensive. The ratio of otolith growth during cold and warm temperature exposure did not differ between groups, and the observed growth pattern is therefore not attributable to differential growth within individual temperature periods. The ratio decreased with otolith size, presumably as a result of ontogenetic decrease in otolith protein composition. These results suggest that processes coupled to the metabolic rate of the endolymphatic epithelium are the key driver behind otolith growth.
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The WAC Bennett Dam was completed in 1968 and impounded the Upper Peace River to form the Williston Reservoir in north central British Columbia. In 1990, an enhancement project was initiated to stock Columbia River Kokanee (non-an...
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The WAC Bennett Dam was completed in 1968 and impounded the Upper Peace River to form the Williston Reservoir in north central British Columbia. In 1990, an enhancement project was initiated to stock Columbia River Kokanee (non-anadromous Sockeye Salmon; Oncorhynchus nerka) from southeastern British Columbia into tributary streams that drained into regions of the reservoir that were accessible by anglers. The current distribution of spawning Columbia-origin Kokanee in the Williston Reservoir watershed, however, does not reflect the locations where these fish were initially stocked and suggests extensive straying. Whether or not Kokanee will develop fidelity to specific spawning locations is not known, but it is important information to effectively manage these introduced fish. We used otolith microchemistry to estimate fidelity to natal streams by Columbia-origin Kokanee in the Williston Reservoir. Otolith elemental signatures for the region of the otolith that formed during the larval period and characterized the natal redd environment showed considerable variation among samples. Natal signatures tended to cluster for each river but not for all spawners, suggesting elemental signatures from other rivers. Homing to one of the four natal streams we examined was classified to be 73% based on linear discriminant analysis, although variation in the elemental signatures within each group suggests that homing by Kokanee to specific natal streams may be as low as 55%. Based on similarity of water elemental signatures for tributaries within large rivers, however, the proportion of fish that returned to their general region was likely higher and estimated to be approximately 83%. The result of regional homing could be reproductive isolation and adaptation to local conditions. It is unclear, however, if the current estimated level of straying will limit genetic differentiation and prevent local adaptation.
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Morphology and morphometry of the sagittae otolith were studied in fish associated with different substrates. The shape, margins and rostrum of three groups of otoliths from several species were analyzed: group 1 (fish associated ...
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Morphology and morphometry of the sagittae otolith were studied in fish associated with different substrates. The shape, margins and rostrum of three groups of otoliths from several species were analyzed: group 1 (fish associated with soft substrates, N = 10 species), group 2 (fish associated with hard substrates, N = 10 species) and group 3 (pelagic fish, not associated with the bottom, N = 6 species). E and R indexes were calculated for each species. The value of E = maximum width of the sagitta (WO)/maximum length of the sagitta (LO)%, expresses the relative tendency in the shape otolith (from circular to elongate). The value of R = length of the rostrum (LR)/LO%, expresses the percentage in the total length of the otolith that corresponds to the rostrum. The sagittae of group I were circular or polygonal with rounded borders. The rostrum can be absent or poorly developed. The sagittae shape of group 2 was elongated, with ornamented borders and a rostrum. The sagittae of group 3 possessed a prominent rostrum, a deep V-shaped cisure and ornamented borders. Statistical analysis showed no significant differences in the E index of groups 1 and 2, while R values of the three groups were significantly different. These results were compared with 80 other species, belonging to 12 families, from the publisher literature. E and R values could be used to characterize the sagittae of the marine fish and could be considered a useful tool for fish ecology studies.
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The otolith length and width of adult teleost Otolithes ruber (Bloch & Schneider, 1801) were used to calculate the fluctuating asymmetry in these two characters. The results displayed that the amount of asymmetry of the otolith width was the highest between the two asymmetry values attained for the otolith of O. ruber. Further, the lowest level of asymmetry in the two otolith characters is at the fish length ranging between 150 and 180 mm and the highest at the fish length ranging between 461 and 2490 mm. The conceivable reason for the asymmetry in this species has been deliberated relative to different pollutants and their presence in the area. A tendency of increase in the asymmetry levels with the fish length was observed for the otolith length and width....
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The otolith length and width of adult teleost Otolithes ruber (Bloch & Schneider, 1801) were used to calculate the fluctuating asymmetry in these two characters. The results displayed that the amount of asymmetry of the otolith width was the highest between the two asymmetry values attained for the otolith of O. ruber. Further, the lowest level of asymmetry in the two otolith characters is at the fish length ranging between 150 and 180 mm and the highest at the fish length ranging between 461 and 2490 mm. The conceivable reason for the asymmetry in this species has been deliberated relative to different pollutants and their presence in the area. A tendency of increase in the asymmetry levels with the fish length was observed for the otolith length and width.
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Otoliths are bony structures inside the fish labyrinth. They are used to determine the age of fish and to identify species based on their remains. The objective of this study was to describe the shape of otoliths in adult European...
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Otoliths are bony structures inside the fish labyrinth. They are used to determine the age of fish and to identify species based on their remains. The objective of this study was to describe the shape of otoliths in adult European perch (Perca fluviatilis), Atlantic herring (Clupea harengus), European sprat (Sprattus sprattus), lesser sand eel (Ammodytes tobianus), great sand eel (Hyperoplus lanceolatus), round goby (Neogobius melanostomus), European whitefish (Coregonus lavaretus), Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), European eel (Anguilla anguilla), viviparous eelpout (Zoarces viviparus), turbot (Scophthalmus maximus), European flounder (Platichthys flesus), European plaice (Pleuronectes platessa) and European smelt (Osmerus eperlanus). Fish were caught in the Gulf of Gdansk. The relationships between the size of otoliths and the length of fish were established for adult European perch, European flounder, Atlantic herring and round goby. Otoliths of taxonomically related species were similar. It was not possible to differentiate otoliths of Ammodytidae, Pleuronectidae, Scophthalamidae, Anguilidae by comparing the presented results with the literature data. Otoliths of Zoarcidae, Osmeridae, Clupeidae, Gadidae, Gobiidae, Percidae and Salmonidae were quite similar but distinguishable. In most of the investigated species, otoliths grow proportionally to the fish size. Their shape does not change during the fish life. The shape of otoliths in the round goby changes significantly. Otoliths of small fish are rounded and significantly lengthen during the growth of fish.
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The effect of food intake and temperature on otolith macrostructure and microstructure was examined experimentally in Atlantic cod Gadus morhua. Daily increment formation was validated and otolith accretion rate and optical densit...
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The effect of food intake and temperature on otolith macrostructure and microstructure was examined experimentally in Atlantic cod Gadus morhua. Daily increment formation was validated and otolith accretion rate and optical density quantified using image analysis. Two-week periods of starvation had no discernable effect on otolith increment width or optical density, despite having negative effects on somatic growth. In contrast, temperature had a strong positive effect on otolith accretion rate and clear effects on optical density with the otolith becoming more translucent at higher temperatures. Somatic growth, otolith accretion and otolith optical density each had a significantly different response curve to temperature. No relationship was detected between individual somatic growth rates and the accretion rate or optical properties of the otolith. The experimental manipulation of temperature-induced otolith patterns similar to the 'false ring' secondary structures sometimes observed in the otoliths of wild fish. The results suggest that otolith pattern arises from a combination of temperature and seasonal effects, but not directly from individual variation in somatic growth.
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The margins of otoliths of Patagonian toothfish (Dissostichus eleginoides) from several samples collected throughout the year were classified as either opaque or translucent. The margins were generally opaque in summer and translu...
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The margins of otoliths of Patagonian toothfish (Dissostichus eleginoides) from several samples collected throughout the year were classified as either opaque or translucent. The margins were generally opaque in summer and translucent in winter. Thus, this species appears to deposit one translucent zone in its otoliths each year, and Counts of these zones are probably a valid method to determine fish age. Comparisons of readings of D. eleginoides otoliths by workers from various institutions indicated a reasonable between-reader consistency, but still suggested that the otoliths were difficult to read. Von Bertalanffy growth parameters were calculated from the author's readings only, separately by sex, for D. eleginoides caught from waters south of New Zealand to the Ross Sea, Antarctica, by longline and trawl fisheries. D. eleginoides appear to be moderately fast growing, at least to about age 10, and reasonably long-lived, reaching at least 50 years. Females grow at a faster rate and reach a larger size than males, but both sexes exhibit comparable maximum ages.
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Two populations of pike Esox lucius have been identified on the eastern coast of Sweden, in the Baltic Sea. These live together, but separate into two different populations during the spawning season. One is an obligate freshwater...
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Two populations of pike Esox lucius have been identified on the eastern coast of Sweden, in the Baltic Sea. These live together, but separate into two different populations during the spawning season. One is an obligate freshwater spawner and the other not only reproduces in ambient Baltic salinities, but appears not to enter fresh water at all.
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The otolith-collic and otolith-ocular reflexes of patients who experienced episodic tilting or translational sensations in the pitch plane without any other vestibular symptoms were assessed using cervical vestibular evoked myogen...
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The otolith-collic and otolith-ocular reflexes of patients who experienced episodic tilting or translational sensations in the pitch plane without any other vestibular symptoms were assessed using cervical vestibular evoked myogenic potentials (cVEMP) and ocular vestibular evoked myogenic potentials (oVEMP). Eleven patients (4 men and 7 women, mean age. =. 40.4) were enrolled. All of the patients complained of episodic tilting or translational sensations in the pitch plane. Patients with a medical history of rotatory vertigo, loss of consciousness, head trauma, or symptoms of central nervous dysfunction or proprioceptive dysfunction and those who had been definitely diagnosed with a disease that causes disequilibrium were excluded. All 11 patients underwent cVEMP and caloric tests. Ten patients participated in the oVEMP tests. Seven of the 11 patients exhibited unilateral cVEMP absences, two displayed bilateral cVEMP absences, one demonstrated unilaterally decreased cVEMP, and one displayed normal cVEMP. Concerning oVEMP, 2 of the 10 patients showed unilateral oVEMP absences, 2 displayed bilateral oVEMP absences, 2 exhibited unilaterally decreased oVEMP, and 4 displayed normal oVEMP. All patients exhibited normal bilateral caloric responses. These findings were distinct from the results obtained for patients who experienced episodic lateral tilting sensations in previous studies. While most of the latter patients exhibited abnormal oVEMP, the patients in the present study tended to display abnormal cVEMP. These results suggest that patients with episodic tilting or translational sensations in the pitch plane suffer from saccular dysfunction. We propose "idiopathic otolithic vertigo" as a clinical entity and suggest that it is caused by idiopathic saccular dysfunction and/or utricular dysfunction.
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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 otolithmotion and thus ear functioning.Yet our knowledge of how ...
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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 otolithmotion 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 plasticitymay 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 com
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