Confirmation of pygmy sperm whale, Kogia breviceps from Palk Bay, India through Cytochrome Oxidase1 (COI) sequence

The identity of a stranded cetacean from the Palk Bay has been confirmed as a pygmy sperm whale (Kogia breviceps) by the partial sequencing of mitochondrial gene cytochrome oxidase subunit-I (COI). The specimen was unambiguously discriminated from the COI sequence of Kogia sima by matching exactly with the sequence of K. breviceps. Stranding events of the pygmy whales are considered to be uncommon. The sequence developed for K. breviceps is the first of its kind attempt from Indian waters.

Brucella sp. sequence-type 27 associated with abortion in dwarf sperm whale Kogia sima

A dwarf sperm whale Kogia sima stranded alive along the Central Pacific Coast of Costa Rica. The whale, handled by tourists and local inhabitants, was weak, had buoyancy difficulties, and eventually aborted and died, showing severe necrotizing placentitis and other pathological signs. Both the mother and the fetus had antibodies against Brucella lipopolysaccharide. Brucella organisms were isolated from various tissues of both animals and were characterized. The bacterium genome corresponded to sequence-type 27 (ST27) and clustered together with other Brucella ST27 isolated in humans and cetaceans.

Echolocation click parameters and biosonar behaviour of the dwarf sperm whale (Kogia sima)

ABSTRACTDwarf sperm whales (Kogia sima) are small toothed whales that produce narrow-band high-frequency (NBHF) echolocation clicks. Such NBHF clicks, subject to high levels of acoustic absorption, are usually produced by small, shallow-diving odontocetes, such as porpoises, in keeping with their short-range echolocation and fast click rates. Here, we sought to address the problem of how the little-studied and deep-diving Kogia can hunt with NBHF clicks in the deep sea. Specifically, we tested the hypotheses that Kogia produce NBHF clicks with longer inter-click intervals (ICIs), higher directionality and higher source levels (SLs) compared with other NBHF species. We did this by deploying an autonomous deep-water vertical hydrophone array in the Bahamas, where no other NBHF species are present, and by taking opportunistic recordings of a close-range Kogia sima in a South African harbour. Parameters from on-axis clicks (n=46) in the deep revealed very narrow-band clicks (root mean squared bandwidth, BWRMS, of 3±1 kHz), with SLs of up to 197 dB re. 1 µPa peak-to-peak (μPapp) at 1 m, and a half-power beamwidth of 8.8 deg. Their ICIs (mode of 245 ms) were much longer than those of porpoises (<100 ms), suggesting an inspection range that is longer than detection ranges of single prey, perhaps to facilitate auditory streaming of a complex echo scene. On-axis clicks in the shallow harbour (n=870) had ICIs and SLs in keeping with source parameters of other NBHF cetaceans. Thus, in the deep, dwarf sperm whales use a directional, but short-range echolocation system with moderate SLs, suggesting a reliable mesopelagic prey habitat.

Host phylogeny and life history stage shape the gut microbiome in dwarf (Kogia sima) and pygmy (Kogia breviceps) sperm whales

Gut microbiomes perform crucial roles in host health and development, but few studies have explored cetacean microbiomes especially deep divers. We characterized the gut microbiomes of stranded dwarf (Kogia sima) and pygmy (K. breviceps) sperm whales to examine the effects of phylogeny and life stage on microbiome composition and diversity. 16S rRNA gene sequence analysis revealed diverse gut communities (averaging 674 OTUs) dominated by a few symbiont taxa (25 OTUs accounted for 64% of total relative abundance). Both phylogeny and life stage shaped community composition and diversity, with species-specific microbiome differences present early in life. Further analysis showed evidence of microbiome convergence with host maturity, albeit through different processes: symbiont ‘accumulation’ in K. sima and ‘winnowing’ in K. breviceps, indicating different methods of community assembly during host development. Furthermore, culture-based analyses yielded 116 pure cultures matching 25 OTUs, including one isolate positive for chitin utilization. Our findings indicate that kogiid gut microbiomes are highly diverse and species-specific, undergo significant shifts with host development, and can be cultivated on specialized media under anaerobic conditions. These results enhance our understanding of the kogiid gut microbiome and may provide useful information for symbiont assessment in host health.

First stranding record of Kogia sima (Owen, 1866) in the Colombian Caribbean

The dwarf sperm whale, Kogia sima, is one of the lesser known Odontoceti species, in spite of its worldwide distribution, and is considered rare due to the difficult identification in the field. Detailed information is scarce and mostly comes from stranding events or bycatch animals, just a few sightings correspond to live specimens. In the Caribbean Basin, the species has been reported in the Lesser Antilles, Mexico, Honduras, Costa Rica and Venezuela. We present the first stranding record of Kogia sima in the Colombian Caribbean coast from a pregnant female in Mendihuaca region, Magdalena Department. The specimen showed no fishing or entanglement lines whatsoever, and the overall condition was good. Morphological measurements were taken and the confirmation of the species was made from the following features: body length, height and position of dorsal fin, position of blowhole, and number of teeth in the lower jaw. The record of the adult specimen is documented in the System of Information of Marine Biodiversity of Colombia –SIBM and the fetus is deposited in the Mammal collection of the Museum of Marine Natural History of Colombia –MAKURIWA under the catalogue number INV-MAM004.