The diet of pygmy sperm whales, Kogia breviceps, stranded in New Zealand: implications for conservation

Abstract

The stomach contents of 27 pygmy sperm whales, Kogia breviceps, stranded on New Zealand beaches between 1991 and 2003 are reported. These individuals comprise 16 males, 10 females, and one for which no sex information is available. The diet was found to include fish and crustaceans, but is comprised primarily of cephalopods, with 0-526 lower beaks, representing an estimated maximum of c. 60 kg of cephalopod prey consumed by any one whale. Cephalopod prey is attributed to 23 species from 13 families, and is dominated by juvenile individuals of the families Histioteuthididae and Cranchiidae (adults of which usually occur at depths exceeding 400 m). Perceived threats to this whale, particularly those affecting distribution and abundance of prey species, are also discussed. These are the first data reporting the diet of this whale species in New Zealand waters. A comparison of the diet of K. breviceps is made with that of the sperm whale, Physeter macrocephalus from New Zealand waters, and with the diet of Kogia known elsewhere.

Stomach contents of long‐finned pilot whales,Globicephala melas, mass‐stranded on Farewell Spit, Golden Bay in 2005 and 2008

“…Despite the substantial opportunity strandings have provided in terms of understanding the biology and ecology of cetacean populations in New Zealand waters, the diet of long-finned pilot whales, Globicephala melas, has been only recently reported (Beatson et al 2007a,b). Of approximately 30 odontocete species occurring in New Zealand waters, the diets of only three others have been described: sperm whale, Physeter macrocephalus (Gaskin & Cawthorn 1967;Clarke & MacLeod 1982;Clarke & Roper 1998;Gomez-Villota 2007); pygmy sperm whale, Kogia breviceps (Beatson 2007); and common dolphin, Delphinus sp. (Meynier et al 2008).…”

Pygmy Sperm Whale (Kogin breiJiceps) stranding record in Tasmania, Australia, and diet of a single specimen

“…listed as a dominant cephalopod prey in all other Pygmy Sperm Whale diet studies, except those from Taiwan (Wang et al 2002), and comprised 73% of the mass consumed by Pygmy Sperm Whales recovered from New Zealand (Beatson 2007). Histioteuthis atlantica has a circumglobal distribution in southern waters and is regularly found in ocean basins, and over shelves and plateaux (Voss et al 1998).…”

“…Plön (2004) found remains of the crustacean Neognathauphausia ingens Dohrn, 1870, as well as large quantities of Octopodidae, Enoploteuthidae, Histioteuthidae and Ommastrephidae (i.e., >20% mass/ individual), and smaller quantities of Chiroteuthidae, Octopoteuthidae, Ommastrephidae and Mastigoteuthidae (i.e., <20% mass/individual). Beatson (2007) investigated Pygmy Sperm Whale diet from 27 stranded individuals in New Zealand, where Pygmy Sperm Whales are one of the most frequently stranded cetacean species. Beatson (2007) found that the diet consisted primarily of mesopelagic cephalopods (23 species from 13 families, dominated by juvenile individuals of the families Histioteuthidae and Cranchiidae), with some fish and crustacean remains also present.…”

“…Beatson (2007) investigated Pygmy Sperm Whale diet from 27 stranded individuals in New Zealand, where Pygmy Sperm Whales are one of the most frequently stranded cetacean species. Beatson (2007) found that the diet consisted primarily of mesopelagic cephalopods (23 species from 13 families, dominated by juvenile individuals of the families Histioteuthidae and Cranchiidae), with some fish and crustacean remains also present.…”

Statistical precision of diet diversity from scat and pellet analysis

“…Other methods, such as stomach contents analysis, are common for fish species (Hyslop, 2006) but are generally not used for most birds and mammals unless the individuals are found dead (e.g. Beatson, 2007), while direct observation is usually prohibited by time or logistical constraints. Scat or pellet analysi s is a particularly useful inexpensive and non-invasive method of studying the feeding ecology of elusive carnivores (Ciucciet al, 1996;Maruccoet al, 2008).…”