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Abstract: There are genetic risks associated with small population sizes, including loss of genetic diversity and inbreeding depression. The southern resident killer whale Orcinus orca population is a group of ~80 whales listed as ‘endangered’ under the U.S. Endangered Species Act. Recovery efforts are focused on increasing prey and reducing impacts from environmental disturbance, but the population's small size and insularity suggest that inbreeding depression could also be important. We analyzed genotypes at 68–94 nuclear loci from 105 individuals to refine a population pedigree to evaluate inbreeding and the relationship between multi‐locus heterozygosity and fitness. Our results expand upon an earlier study and shed new light on both inbreeding within this population and the mating patterns of killer whales. We found that only two adult males sired 52% of the sampled progeny born since 1990. Confirming earlier results, we found male reproductive success increased with age. Based on the pedigree, four sampled offspring were the result of inbred mating – two between a parent and offspring, one between paternal half‐siblings, and one between uncle and half‐niece. There is no evidence to date that the survival or fecundity of these individuals is lower than normal. There was some evidence for inbreeding depression in the form of a weakly supported relationship between multi‐locus heterozygosity and annual survival probability, but the power of our data to quantify this effect was low. We found no evidence of inbreeding avoidance in the population, but a late age of breeding success for males may indirectly limit the frequency of parent/offspring mating. The effective number of breeders in the population is currently ~26, and was estimated to have ranged from 12–53 over the past 40 years. The population that produced the oldest (pre‐1970) sampled individuals was estimated to have 24 effective breeders. Overall, our results indicate that inbreeding is likely common in the population, but the fitness effects continue to be uncertain. [ABSTRACT FROM AUTHOR]

We evaluated harbor porpoise ( Phocoena phocoena (Linnaeus, 1758)) strandings in the Salish Sea to determine calving seasonality (1980-2015). A total of 443 strandings were analyzed, of which 134 were calves and 53 were neonates. Stranded calves were reported every month, but peaked in July, August, and September. Based on fetal size and an estimated fetal growth rate of 80 mm/month, mean (±SD) conception date (and range) was back-calculated to 11 October ± 30 days (16 August - 31 December) and was later than in most other studies. Using mean (±SD) length at birth (80 ± 5.8 cm), gestation was estimated to be approximately 10.8 months. Estimated birthing period was 16 July - 27 November, with a mean (±SD) birth date of 10 September (±30.7 days) and a birth length of 80.0 cm. Estimated pregnancy rate (0.28-0.29) is lower than reported in other areas and is likely an underestimate due to missed early embryos, poor postmortem condition of a large proportion of the stranded adult females, and potential biases related to the animals that strand and are available. This study of harbor porpoise reproduction and calving in the Salish Sea is the first assessment of calving seasonality for this species in the northeast Pacific Ocean. [ABSTRACT FROM AUTHOR]

We show how to calculate the spectrum of the Laplacian operator on fully symmetric, finitely ramified fractals. We consider well-known examples, such as the unit interval and the Sierpiński gasket, and much more complicated ones, such as the hexagasket and a non-post critically finite self-similar fractal. We emphasize the low computational demands of our method. As a conclusion, we give exact formulas for the limiting distribution of eigenvalues (the integrated density of states), which is a purely atomic measure (except in the classical case of the interval), with atoms accumulating to the Julia set of a rational function. This paper is the continuation of the work published by the same authors in Ref. 1. [ABSTRACT FROM AUTHOR]