To glue or not to glue? Reassembling broken otoliths for population discrimination.

Twenty-five Atlantic cod Gadus morhua otoliths were examined using eight shape measurements along with Fourier analysis of their outlines to test whether discrimination using otolith shape is affected by gluing broken otoliths. Small differences in seven of the eight shape measurements were found between unbroken otoliths and the same otoliths after breaking and subsequently gluing together; however, none of the Fourier descriptors differed. Cluster analyses indicated that resultant morphological differences will have no impact when applying discriminant analysis.

Identification of stock components using morphological markers.

This study investigated the development of a quantitative method for distinguishing stock components of Icelandic cod Gadus morhua based on visual examination of morphology. The stock is known to be structured into genetically distinct geographic components (north and south of Iceland) and behavioural types that spawn sympatrically. Differences in morphology were tested between locations, genotypes (a proxy for behaviour) and sexes. Results show morphological markers on the head, fins and body of G. morhua that are correlated with the sex, genotype of the fish at the pantophysin (pan-I) locus and the location at which the fish were caught. Females were found to have relatively deep bodies, and the pan-I(BB) genotype (associated with deep-water feeding behaviour) have greater gaps between their fins. Overall, morphology is more useful for distinguishing sympatric genotypes but less powerful at identifying genetically distinct geographic sub-populations, perhaps because counter-gradient evolution reduces phenotypic differences even with an underlying genetic cause.

Contrasting trends in two condition indices: bathymetric and spatial variation in autumn condition of Icelandic cod Gadus morhua.

Bathymetric and regional variation in condition of Icelandic cod Gadus morhua in autumn is compared to that previously observed in spring. Once again, contradicting patterns in the hepato-somatic index and a morphometric index of fish condition were observed. The relevance of this persistent spatial variation in condition in relation to emerging evidence of behavioural types is discussed.

Retrospective assessment of premenstrual changes in Icelandic women.

The purpose of this study was to increase our knowledge of the condition of Icelandic women aged 29 to 40 years during the premenstrual phase of the menstrual cycle. Premenstrual symptoms were measured by a retrospective instrument adapted from Halbreich and colleagues' Premenstrual Assessment Form. Our findings showed that Icelandic women experience premenstrual changes as do their peers in other countries. The most common symptoms were bloating, mood swings, irritability, abdominal discomfort-pain, and intolerance-impatience. Women who were symptomatic in the week before menses tended to manifest more symptoms at other times as well. In general, women responded to their symptoms by taking some time to relax, take pain medication, or seek support. Women experiencing more severe symptoms were more likely to seek support from a partner, relative, or friend. More than 40% of the sample reported that they perceived the symptoms as having negative effects on their relationships with their partners and children, and those experiencing more severe symptoms were more likely to report these perceptions.