Soviet catches of southern right whales Eubalaena australis, 1951–1971. Biological data and conservation implications

Blubber thickness in right whales Eubalaena glacialis and Eubalaena australis related with reproduction, life history status and prey abundance

“…Acoustic blubber thickness data from Eubalaena glacialis presented here (range = 8 to 22 cm) were com parable to ruler measurements of blubber thickness from along the dorsal midline at the level of the axilla collected during necropsy of E. glacialis (range = 8 to 17 cm; Moore et al 2004). E. australis acoustic blubber thickness data (range = 5 to 26 cm) were comparable to those reported during Soviet whaling (range = 5 to > 30 cm; Tormosov et al 1998), where measurements were taken mid-laterally at the level of the anus. The difficulties inherent in measuring blubber thickness on carcasses often result in inconsistencies within and between data sets; therefore, comparisons within and between such data sets should be made with caution.…”

“…Blubber thickness and body length were not related in gray whales Eschrichtius robustus (Rice & Wolman 1971). Tormosov et al (1998) plotted a positive linear relationship between blubber thickness and body length in Eubalaena australis taken by Soviet whaling operations. Blubber thickness and body length were not related in E. glacialis when all data were analyzed together (Fig.…”

“…In balaenopterid whales, blubber thickens during the summer feeding season and thins during the winter migration (see Lockyer 1981 for review). Summer seasonal fattening was not detected in measurements of blubber thickness in southern right whales taken by whaling (Tormosov et al 1998). Such fattening may not have been detected due to pooling the data over a 6 yr period (Tormosov et al 1998), differences in individual whale arrival times to the feeding grounds (e.g.…”

“…Post mortem measurements combined from a 6 yr collection period suggested that Eubalaena australis blubber thickness does not increase during the summer feeding season (Tormosov et al 1998). According to photogrammetric measurements of body width in E. glacialis and E. australis, dorsal body shape was significantly thinner in lactating females than non-lactating, non-pregnant females (C. A. Miller unpubl.…”

“…Such measurements of blubber thickness are typically collected during necropsy with a ruler (e.g. Lockyer et al 1985, Koopman 1998, Tormosov et al 1998 or during live-captures with ultrasound (Curran & Asher 1974, Gales & Burton 1987. A technique to measure blubber thickness in free-ranging right whales using amplitude-mode ultrasound was developed by Moore et al (2001).…”