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Identification of discrete stocks of Greenland halibut is an important aspect of proper fisheries exploitation. Available literature data indicated a lack of significant inter-area differences between Greenland halibut populations from the Northeast Atlantic. To define the population diversity, two aspects were taken into account: enzyme-genetic diversity and the concentration of heavy metals in tissues. Seven allozyme loci variations were used to characterize the genetic structure of four populations of Greenland halibut from the Western Barents Sea region. The samples were collected from the spawning area in the period when this species took migration to spawn. The sample RH4 was significantly different from the other samples collected from the same location (RH2 and RH3) and depth for over two days. Another sample (RH8), collected from the nearby area 6 days later was similar to the samples RH2, RH3. We noticed a significant divergence between the sample RH4 and the three remaining samples, where the value of the index FST fluctuated about 0.40 and approximately 0.01 between three similar populations. This genetic fluctuation negates the thesis of a panmictic character of the Western Atlantic population. Feeding groups of Greenland halibut are moving along the Barents Sea shelf and they are exposed to different heavy metals concentrations according to the food preferences or the exact place of feeding. We identified similar concentrations of heavy metals, i.e., Zn, Cu, Cd, and Pb in all samples. Trace metal analysis of aquatic organisms from the Barents Sea can provide important information on the degree of environmental contamination, and the potential impact of seafood consumption. [ABSTRACT FROM AUTHOR]

The genetic variability in selectively controlled in Bulgaria local honey bee populations, representing Apis mellifera macedonica subspecies (type “rodopica”), has been studied by usage of alloenzymic analysis of six enzymic systems (MDH-1, ME, EST-3, ALP, PGM and HK) corresponding to 6 loci. Totally 324 worker bee individuals from 9 different local populations belonging to breeding stock of National Bee Breeding Association were included in this investigation. All of the studied loci were found to be polymorphic in most of the populations with the exception of EST-3 locus which was established to be fixed in two of investigated populations. Polymorphism with three alleles was ascertained for MDH, ME, ALP and PGM loci and with four alleles – for EST-3 and HK loci. The most common alleles in all of the investigated populations were ME 100, EST-3 100, PGM 100 and HK 100. Two private alleles (frequency < 0.05) were found for two of the studied populations. The calculated level of polymorphism was between 88.33% and 100%. The observed and expected heterozygosities were found to range from 0.186 to 0.301, and from 0.205 to 0.305, respectively. The calculated mean Fst level was 0.028. Allele frequencies of all studied loci were used to estimate Nei’s (1972) genetic distance, which was established to range between 0.001 and 0.028 among the selectively controlled populations studied. The assignment test showed a high level of consolidation for the all studied populations.