Estimation of mortality coefficients and survivorship curves for minke whales (Balaenoptera acutorostrata) in Korean waters

Abstract

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients (q t ). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The q t for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the q t was taken into account. The mortality coefficient, survival rate, q t and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

Collisions between Whales and Fast Ferries around Korean Waters

“…The effect of ship strikes on the survival of cetaceans that are distributed around Korean waters is not high at present, compared with other threats, such as entanglement in fishing gear [10][11][12][13][14][15]. Among various threats to cetaceans, entanglement in fishing gear is the most significant threat to the survival of cetaceans around Korean waters at present, rather than ship strikes.…”

Potential areas for whale watching in Korean waters

“…Human-induced mortality of cetaceans, including bycatch, has continuously occurred in Korean waters (Song 2010(Song , 2011Song, Kim, Zhang, & Kim, 2010;Zhang, Song, & Na, 2010).…”