Genetic variation at enzyme loci in North Atlantic minke whales,Balaenoptera acutorostrata

Abstract

Electrophoretic variation within and between North Atlantic minke whale samples (Balaenoptera acutorostrata) from West Greenland, Iceland, and Norway was investigated. In the West Greenland samples, 28 enzyme systems were examined, representing 36 loci, of which 6 were found to be polymorphic. In Icelandic and Norwegian samples, 22 enzyme systems were examined, representing 29 loci, of which 6 and 5 were found to be polymorphic, respectively. The average heterozygosity was 0.058 (SE = 0.024) in samples from West Greenland, 0.074 (SE = 0.028) in samples from Iceland, and 0.054 (SE = 0.023) in samples from Norway. No significant deviations from the expected Hardy-Weinberg genotypic frequencies, within samples taken from the same area, were found. Significant differences in allele frequencies were observed, however, between samples from the three different areas. The average Nei's genetic distance was 0.014 and the average Fst value was 0.126. The genetic differences between the samples from the different areas indicate that those from West Greenland, Iceland, and Norway represented different breeding populations.

Genetic population structure of minke whales Balaenoptera acutorostrata from Greenland, the North East Atlantic and the North Sea probably reflects different ecological regions

“…One explanation for the finding in the present study of 2 genetically different sub-populations of minke whales in West and East Greenland could be that the minke whales from East Greenland constitute a part of the Central North Atlantic stock or sub-population. This explanation was actually suggested by the analysis of population structure in this study (see 4 below) and also by the results of 2 isozyme studies by Danielsdóttir et al (1992Danielsdóttir et al ( , 1995, who observed significantly different allele frequencies between minke whales from West Greenland and Icelandic waters. The latter group is thought to be a part of the Central North Atlantic sub-population.…”

“…The average heterozygosity observed at the 16 microsatellite loci (Table 4a,b) found in the present study was considerably higher than the heterozygosity levels obtained from allozyme data. Danielsdóttir et al (1992) examined 36 allozyme loci in a total of 173 minke whales representing the suggested West Greenland, Central, and NE Atlantic sub-populations. The observed heterozygosity (H 0 ) ranged from 0.080 to 0.580 (6 polymorphic loci) in the West Greenland sample, from 0.096 to 0.450 (6 polymorphic loci) in the Central and from 0.083 to 0.417 (5 polymorphic loci) in the NE Atlantic sample (Danielsdóttir et al 1992).…”

“…Danielsdóttir et al (1992) examined 36 allozyme loci in a total of 173 minke whales representing the suggested West Greenland, Central, and NE Atlantic sub-populations. The observed heterozygosity (H 0 ) ranged from 0.080 to 0.580 (6 polymorphic loci) in the West Greenland sample, from 0.096 to 0.450 (6 polymorphic loci) in the Central and from 0.083 to 0.417 (5 polymorphic loci) in the NE Atlantic sample (Danielsdóttir et al 1992). The difference in heterozygosity found in the 2 studies was probably caused by the higher mutation rate of the microsatellite loci (10 -3 , Weber & Wong 1993) compared to protein coding loci such as allozymes (10 -9 , Nei 1987).…”

“…Previous studies applying various genetic techniques found indications of population sub-structuring in North Atlantic minke whales (Palsbøll 1989, Árnason & Spillaert 1991, Danielsdóttir et al 1992, Bakke et al 1996, Martinez et al 1997, Martinez & Pastene 1999. However, as these studies included samples taken in different years, it is unclear to what extent inter-annual variation influenced spatial comparisons.…”

Sex hormone concentrations in blood serum from the North Atlantic fin whale (Balaenoptera physalus)

“…Additional work, however, is needed to establish reference values for hormonal concentrations for the various sexual conditions and categories within this species, not only in blood but also in various tissues already collected. This together with accumulating data and improved understanding of other aspects of the fin whale stocks in the North Atlantic Ocean, such as recent genetic studies (Daníelsdóttir, Duke, Joyce & Arnason, 1991; Árnason, Daníelsdóttir, Spilliaert et al 1992) and tracking experiments (Watkins, Moore, Sigurjónsson et al 1984), will greatly facilitate the assessment of fin whale abundance and productivity in different geo¬ graphical areas and support future surveillance of the stocks.…”