Distnbution of oxygen and carbon stable isotopes in fish otoliths from a wide range of species was invesugated to determine if the isotopes were deposited in equilibnum with ambient seawater and the potential utihty of isotope data to studies of fish biology Companson of 6180 and 6 I 3 c data from otoliths w t h estimates of equilibnurn aragonite indicate that ''0, but not I3C was deposited near equdibnum and this confirms the utllity of otolith oxygen isotopes as an indicator of ambient temperature The departure of 613C from equilibrium was considered In light of several current theones on 13c isotope disequilibrium There was a strong correlalon between bI3C and temperature and, concomitantly a strong relationship between 6180 and 6I3C Evldence is presented to support the Importance of metabolic effects in medialng I3C disequdibna and a strong relationship between metabohc rate (VO?) and 6I3c is hypothesized F~s h e s with low metabolic rates or those living at low temperatures had 13C deposited near to equilibnum whereas fishes living at higher temperatures showed extreme depletion in otolith I3C Trends were also evident in 613C values in luveniles and adults of a species with the juveniles presumably with a higher metabolic rate being more depleted in I3Cthan the adults The study shows that both oxygen and carbon stable isotopes have great potential in studies of fish biology and are worthy of further investigation

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The growing otoliths of fish incorporate radiocarbon in concentrations that are equivalent to that found in ambient seawater dissolved inorganic carbon. Therefore, pulses of anthropogenic radiocarbon produced by the atmospheric detonation of nuclear weapons can ultimately be detected in otol~ths. This study estimates the age of large southern bluefin tuna Thlinnus maccoyii using an age estimation procedure based on the determination of levels of bomb-derived radiocarbon In their otoliths. Radiocarbon data from selected regions of southern bluefin tuna otoliths indicate that this species may reach ages in excess of 30 yr Furthermore, individuals that approach the asymptotic length are likely to be 20 yr of age or older. The data agree generally with accepted models of southern bluefin growth, but show that these fish live longer than was believed previously. Comparisons between otolith section and bomb radiocarbon age estimates indicate that reading otolith sections is an effective method to estimate the age of larger southern bluefin. The presence of a significant number of individuals greater than 20 yr of age in the southern bluefin population may alter estimates of natural mortality rates currently used in Virtual Population Analysis models for stock assessment of this species.

Blue grenadier, Macruronus novaezelandiae, or hoki as it is known in New Zealand, spawns at two distinct localities off New Zealand. Earlier research on morphometrics and on age and growth suggested that these spawning localities are used by two discrete stocks; however, the research was not conclusive. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used to analyse trace elements in otoliths from adult blue grenadier collected at the two spawning sites. Before analysis, portions of otoliths formed during juvenile and adult life were isolated and these segments were analysed separately. With a cross-validation procedure (jackknife), it was possible to classify correctly 100% of the samples in relation to age (juvenile v. adult). On the basis of the jackknifed discriminant functions, classifications of blue grenadier in relation to sex or capture locality were not significantly different from random. The results are not definitive in determining stock structure of New Zealand blue grenadier but do provide insight into the application of otolith trace element chemistry in studies of stock structure.

Beckwith-Wiedemann syndrome (BWS) is a multisystem human genomic imprinting disorder with variable clinical expression and complex molecular aetiology 1. BWS is an overgrowth syndrome, with patients often presenting with macroglossia, abdominal wall defects, hemihy perplasia (lateralized overgrowth), enlarged abdominal organs and an increased risk of embryonal tumours during early childhood. BWS is caused mainly by genetic or epigenetic defects within the chromosome 11p15.5 region 2. This region contains imprinted genes, such as CDKN1C and IGF2, which are strong regulators of fetal growth. Although BWS might present prenatally or in adult life, it is most commonly diagnosed in the neonatal period or in early childhood, with an estimated prevalence of 1 affected child