This blog entry allows a very visual insight into our conservation progress.

Following condition assessing and documenting the cetacean specimens, treatment plans were made (see previous blog ‘Treatment decisions, decisions, decisions‘). Hands-on conservation commenced with dry cleaning the specimens one by one, to remove over 100 years worth of accumulated dust. This was followed by the second treatment phase focusing on addressing degraded oil residues formed on the surface of the bones.
Along the way, a few discoveries were made…

1) Removing layers of dust with a vacuum and brush

Vacuuming the Northern Bottlenose Whale vertebrae (Hyperoodon ampullatus (Forster, 1770))

2)    Reducing degraded oil residues on bone surfaces with an ammonia solution

Treating the Beluga Whale’s (Delphinapterus leucas (Pallas, 1776)) ribcage with ammonia / treated area of Northern Bottlenose Whale sternum

Northern Bottle-Nose Whale’s oil soaked skull versus treated vertebrae

Beluga Whale vertebrae before (showing water marks) and after ammonia treatment

3 Reducing degraded oil residues on cartilage/bone areas

Detached Bottlenose Dolphin (Tursiops truncatus Montagu, 1821) fin before and after ethanol/ammonia treatment

4 Removing miscellaneous foreign matter 

Giving the Killer Whale (Orcinus orca (Linnaeus, 1758)) a dental check-up (incl. swabbing with ethanol)

Old piece of cotton wool in Killer Whale’s skull cavity, suggesting previous unrecorded treatment

5 Discoveries made during treatment

Pencil figure ‘3’ on 3rd chevron of Bottlenose Dolphin (undated curator’s mark?)

First edition catalogue label ‘1673’ on rib of Killer Whale

Early (honest) treatment evaluation

While we are finding that oils on the bone surface are efficiently being solubilised by treatment with ammonia, we do not know how far the solution penetrates the bone and how much it facilitates a migration of oil from the core to the surface. It is difficult to judge to what extent treatment removes the currently degraded oil residues on the surface, without actively drawing out oil from the bone matrix. In some treated areas the bone surface takes on an orange tint, suggesting un-oxidised oils have indeed been drawn to the surface. Unfortunately at this stage, and without further analysis, it is difficult to predict the level of remaining oil in the bone and how distant in the future the cetacean specimens may require re-treatment.

While this phase of the cetaceans’ treatment is physically demanding (exasperated by working in Tyvek suits during a heatwave), and repetitive given that the project involves five large, suspended cetacean skeletons, the work is nevertheless rewarding. We’ve each adopted our own whale family members, who are affectionately seen through a new chapter in their museum lives.

Join us again for our next blog entry, where we will share images from our ‘bone rearticulation workshop’…

Gemma Aboe, Assistant Conservator