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Otolith Section (otolith + section)

Distribution by Scientific Domains
Earth and Environmental Science100%

Selected Abstracts

Relative contributions from exposed inshore and estuarine nursery grounds to the recruitment of stone flounder, Platichthys bicoloratus, estimated using otolith Sr:Ca ratios

FISHERIES OCEANOGRAPHY, Issue 4 2000
Yoh Yamashita
In Sendai Bay, stone flounder larvae settle and spend their juvenile period in either shallow exposed inshore nursery grounds or estuarine nursery grounds. The purpose of this study is to examine the relative contributions of these two kinds of nursery grounds to the flounder population using otolith strontium:calcium ratios. Stone flounder juveniles were collected from both nursery grounds, and one- and two-year-old flounder were caught deeper in Sendai Bay. Sr and Ca content in the otoliths were measured by electron probe micro analysis. The Sr:Ca ratios in the otolith section corresponding to the early postsettlement period ranged from 3.06 to 3.85 for the exposed inshore areas with stable low temperature and high salinity conditions, and from 3.81 to 5.32 in brackish estuaries with high temperature and low salinity conditions but with large diel and tidal cyclical fluctuations. Values from an estuarine site with stable salinity ranged from 3.58 to 4.15 overlapping with both the above ranges. Rearing experiments supported our inference that the high otolith Sr:Ca ratios of juveniles inhabiting estuarine nursery grounds are attributable to higher temperature and physiological stress caused by the large diel temperature and salinity fluctuations within the estuaries. Estimation of the Sr:Ca ratio of recruited fish using the otolith section formed while in the nursery area showed that at least 20 out of 42 individuals examined originated from estuarine nursery grounds. The present study indicates that estuaries play an important role as nursery grounds for stone flounder, producing about half of the stock in spite of the small and restricted area compared with the wide expanse of the exposed inshore area. [source]

Demonstration of a new calibration standard for strontium measurements in otoliths based on high energy Sr ion implantation

JOURNAL OF FISH BIOLOGY, Issue 3 2002
R. W. Gauldie
A new Sr measurement standard is given for biominerals based on implanting an exactly known number of Sr atoms into an otolith section using ion-beam implantation and pre- and post-implantation ion beam (PIXE) scanning. [source]

Restricted fish feeding reduces cod otolith opacity

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2008
H. Høie
Summary The purpose of this work was to examine the effect of reduced feeding and constant temperature on cod otolith opacity. Three groups of juvenile cod were given restricted food rations at different times for 4 months, resulting in depressed somatic growth. Otolith opacity was measured on pictures of the otolith sections. The otolith carbonate deposited during the experimental period was generally opaque compared to the more translucent otolith material deposited prior to and after the experimental period, when the fish were kept in a pond and in sea-cages at higher temperatures. Large variations in otolith opacity were found between individual fish both within groups and between groups. In two of the three groups significantly more translucent otolith material was deposited in response to reduced feeding. Our results show that variations in feeding and hence fish growth resulted in variation in otolith opacity, but the effect was minor compared to that of variations in ambient temperature. The combined influence of these effects, which both act on fish metabolism, are most likely controlling the seasonal opacity changes observed in wild fish. Our results help explain the variations seen in fish at constant temperatures. [source]

Age determination and growth of turbot and brill in the Adriatic Sea: reversal of the seasonal pattern of otolith zone formation

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2001
E. Arneri
The growth of two commercially important flatfish, turbot (Psetta maxima) (L.) and brill (Scophthalmus rhombus) (L.), was investigated in the Adriatic using whole otoliths (sagittae) and stained otolith sections. At variance with the pattern usually observed in temperate seas, the opaque zone was found to be laid down in autumn and winter, and the translucent zone in spring and summer. Growth rates differed according to sex, with the females attaining greater body lengths. The von Bertalanffy growth parameters were: L,=66.2 cm, K=0.31 years,1, and t0=,0.14 years for turbot males, L,=81.5 cm, K=0.21 years,1, and t0=,0.48 years for turbot females; L,=40.2 cm, K=0.49 years,1, and t0=,1.03 years for brill males; L,=50.1 cm, K=0.27 years,1, and t0=,1.75 years for brill females. Growth rates and maximum age recorded for turbot were comparable to those reported in the North Sea. [source]