Thames whale - initial post mortem comments

Dr Paul Jepson, pathologist and head of the Marine Mammal Stranding Project based at ZSL Institute of Zoology in London, today revealed initial thoughts and findings on the health of the young female whale which died on Saturday. What follows is an abridged version of the initial findings from the post mortem findings discussed during today's press conference hosted by ZSL (IofZ) and BDMLR:

If the whale had been released would it have returned to the Thames?
There was no definite answer to this as this was the first bottlenose whale rescue attempt in the Thames area, therefore there are no records to draw upon, however they are now looking into the possibility of records elsewhere of beaked whales that have got out of estuaries successfully but re-stranded or otherwise.

Was there a way out for her?
There is a way out at the top and bottom area of the North Sea, but working from the position in which the rescue team were placed in this instance, the best chance they could give the whale was to get her out of the Thames and return her to deeper waters.

Had the whale eaten?
Examination of the stomach contents showed that the whale had eaten (there were squid beaks intact in her stomach). Her nutritive condition and blubber thickness were both good, and changes came about when she moved from her natural waters to into the Thames where her food source (squid) were not available.

Any idea how long the animal had been struggling to get back out to sea?
Impossible to say precisely, but days rather than weeks as she was in good condition.

Have there been rescue attempts on marine mammals before and if so, have they been successful?
BDMLR have been involved in rescue and release for 18 years now. Four years ago a rescue attempt was made on a small Minke whale at Dartford, however as it was still maternally dependent it could not be saved.

Could anything else have been done to save the Thames whale?
Everything that could be done, was done. Decisions were always made with the welfare of the animal and safety of the rescue crew at heart. Mark Stevens, a director of BDMLR, commented that the rescue team worked well and everything in the text book developed by BDMLR and used by Marine Mammal Medics in a stranding situation, was followed. Mark went on to say that one thing that would perhaps have been of assistance would have been bigger equipment (straps etc), however as a small charity with a working team of volunteers, they do not have the money to put into this and had to use what was available to them in the time. The team were under tight time constraints as the London Port Authorities had advised that should they need to move the whale out of the river they would have to have the rescue underway by 3pm, or the barge would be bridge-bound due to the rising tide.

Have you any idea why the whale died when she did - would she have survived much longer?
The animal was severely dehydrated (whales and dolphins obtain their required daily water quota via their food), and as the whale had not eaten since entering the Thames, her water levels were very low. Also, blood tests showed some muscle damage and kidney mal-function however until this is looked at in greater detail it is not known if there was any disease present and if so, whether the whale was diseased before she entered the Thames or became infected whilst here.

Was this a young whale still dependent upon her mother?
No, she would have been too old - based on her body length she was not maternally dependent and able to feed for herself (as the squid remains prove). It is however possible that she was travelling with a group (pod) and became separated.

What tests are now being carried out?
Tests are being conducted to see if she had any infectious agents or bacteria plus other pathological investigations, the results of which will be available in the next couple of weeks. Also tests will be carried out for chemical contaminants; heavy metals, PCB's etc., results will be available in around 2 months time. However, in general beaked whales such as this, tend to have low levels of pollutants due to their habitat and feeding range (being ocean depths of 1,000m+), therefore unlike coastal dwelling animals such as dolphins and porpoises, whose food source can be heavily affected by chemical pollutants which then enter the animal via the food chain and are stored in their thick blubber, beaked whale food sources tend to be less polluted with chemicals.

Would the whale have died eventually if left unattended?
Yes, due to the pressure on the internal vital organs of the animal when it strands. For this reason the padding/inflatable pontoons are essential to help support the body weight. Every rescue is different, and as this was the first stranding and rescue of this species of whale in the area, there was nothing to compare this with, which is why every effort was made to release her as soon as a suitable area was decided upon rather than keep her on the boat for too long.

How is evidence of stress usually shown/proven in a marine mammal?
Animals which have been chronically stressed have high parasite burdens, are very underweight and show clear evidence of lung disease, causing changes in the adrenal gland which appears thickened and clearly shows up in post mortem examination. This whales' adrenal glands were normal, suggesting that any stress incurred was limited to her time here in the Thames.

General comments:

• The whales' navigational system appears normal, however samples have been sent to specialists in the Canary Islands for comment.
• Regarding the removal of the animal on the barge; her respiratory rate and behaviour were monitored to ascertain how she was being affected by the situation. All the whales' vital signs showed she was stable which is why the decision was made to attempt a release, however at 6.30pm on Saturday evening her condition deteriorated and she began to convulse. This was caused by the rapid deterioration in her condition, and as she was at this point very ill, a decision had been made to euthanize the animal to stop her suffering further, however as Dr Jepson was about to administer the lethal injection, the whale died naturally.
• The specimen is now being stored at the ZSL storage facility in South West London and will be available in the future for research purposes. The Marine Mammal Project follows a very systematic post mortem protocol, and has done for the past 15 years. All post mortems on whales and dolphins are carried out in the same way, but as few post mortems have been carried out on beaked whales, more samples have been taken in this case. It is hoped that this will not only assist with immediate research which is obviously important to ascertain the cause of death in this instance, but also samples taken will be made available to assist with future research.
• Occasionally these large whales simply appear to get the navigation wrong. We don't know why they get there in the first instance which is why for the past 15 years, research has been carried out which will hopefully help ascertain at some point in the future, why these larger whales end up in the North Sea.
  
  credits :
  Dr Paul Jepson, ZSL Institute of Zoology
  British Divers Marine Life Rescue
  
  PLEASE NOTE: As these are personal notes taken and not direct quotes from the participants, the Marine Connection apologise for any error or omissions in content. The above should be taken as a guide only to the answers and questions submitted during this conference.