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LatestPhoto
A 55-foot sperm whale is entangled in an illegal driftnet in Italy in 1996. Entanglement is a terrible stress for an animal that lives completely free in the open ocean, unfortunately such encounters are usually fatal. Illegal driftnetting is of critical concern as the current rate of sperm whale entanglements is cited as indicative of this speciesŐ decline in the Mediterranean Sea.
Photo Courtesy of Dr. Antonio Di Natale

October 22, 2004
Disentangling Sperm Whales from Driftnets
Real Audio Report
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Log Transcript

This is Genevieve Johnson speaking to you from the Odyssey in the Mediterranean Sea.

In the previous Odyssey log, we discussed the illegal driftnet fishery in the Mediterranean Sea. Driftnets are long, free-floating walls of net, often referred to as 'walls of death'. The tough polyfilament fiber is designed to entangle large pelagic fish - primarily swordfish. However, these nets are not selective, and also entangle large numbers of small and large cetaceans. Despite a 2002 European Union ban on driftnets of all sizes, driftnetting continues in several countries with an estimated 600 boats currently working illegally in the Mediterranean Sea.

A 2004 assessment report submitted to the International Union for the Conservation of Nature (IUCN) stated that - 'the main known cause of sperm whale decline in the Mediterranean is bycatch in high-seas swordfish driftnets, which has caused high levels of mortality since the mid-1980s'.

According to a summary of records from the waters of Spain, France and Italy between 1971-2003, 229 sperm whales were reported as entangled in fishing gear, carrying entanglement scars, or stranded as a result of being entangled - a stranding rate among the highest in the world.

Dr. Antonio Di Natale is a Fisheries Biologist and the Scientific Director of the Genoa Aquarium in Italy. He has worked with whales since 1974 and also works to release sperm whales entangled in driftnets in Italy.

Of large cetaceans, the sperm whale is most affected by this fishery. The enormous, blunt nose crashes against the net causing it to become entangled in stantaneously. According to Dr. Di Natale there are then several problems faced by the animal.

LatestPhoto
Dr. Antonio Di Natale is a Fisheries Biologist and the Scientific Director of the Genoa Aquarium in Italy. He has studied cetaceans since 1974 and together with Centro Studi Cetacei works to release sperm whales entangled in driftnets in Italy.
Photo - Chris Johnson

Dr. Anotonio Di Natale -

    "One of the problems is when they are stopped by a driftnet, it's a terrible stress for an animal that usually is completely free in open ocean. Only this is able to create a killing stress to the animal. Then there is a problem caused by the amount of net, sometimes the amount of net is able to sink the animal, killing the animal in any case. The third problem we have found on one occasion is that the animal tries to break the net and ingests a certain amount of net inside the stomach, this is able to kill the animal as well - so the problem is not so easy and the fisherman cannot do anything when this happens."

Every driftnet fisherman is reluctant to report any entanglement of a marine mammal - primarily because the fishery is illegal, and because the statistics will support the findings that this fishery maintains an unacceptable bycatch of marine mammals.

Over a period of years, Dr. Di Natale built up a network through which some of the fishermen find a way to send a message to his rescue team who can then try and release the animal.

Dr. Anotonio Di Natale

    "This is not so easy because you need to get information as soon as possible, more or less in real time. A good information system that we have in Italy with an observer in several landing points for Fisheries reasons and are able to refer about these types of entanglements when they are aware of this and we have a good rescue team around Italy. There is a good organization that worked very well in the past, initially it was called 'Project Cetacean', then we established a national network called 'Centro Studi Cetacei' that worked.

    Usually when we get this type of information, we immediately go to sea with one of the State Corps, the Italian Custom Police and in other situations the Coast Guard or the fire department. Trying to help the animal with divers, but first by cutting the net from outside the water from an inflatable boat and cutting the net on the back. Then going inside the water - diving, and cutting the net around the head or around the tail. Their reaction is usually quite good from the sperm whale, sometimes it is not and is able to create serious trouble to the divers - but we have never had an accident luckily and we always rescue the animals."

Dr. Di Natale explained how sometimes the amount of net around the whale is so massive, the team must work for several days to free it. The best method of cutting the net is by knife. However the thick polyfilament line is difficult to cut and blunts the blade within minutes. There is always somebody on the vessel continuously sharpening the knives.

LatestPhoto
Dr. Di Natale and his team regularly risk their lives trying to save sperm whales entangled in fishing gear. Incredibly, this whale opens its mouth allowing Dr. Di Natale to cut the net from around the jaw and between the teeth.
Photo Courtesy of Dr. Antonio Di Natale

Eight sperm whales were entangled in southern Italian waters this year alone. Dr. Di Natale and his team managed to release 7, unfortunately one died. In total, Dr. Natale has personally rescued or assisted in the release of 18 sperm whales in Italian waters."

These animals suffer appallingly when entangled, and every rescue is a victory for the team. However, for Dr. Natale, there is one incident he will always remember.

Dr. Anotonio Di Natale -

    "There is a particular story about a rescue operation, it happened in 1996 in the Southern Tyrrhenian Sea close to the Eolien Islands . We had been called to rescue a huge male, more than 19 meters (55 feet); it was completely entangled in a driftnet a few miles off the island of Stromboli during the first day. The first day we tried to cut the huge amount of net around the body, but then the sea became rough and we lost the animal.

    We found the animal again after one week close to the island of Vulcano - also in the Eolien Archipelago. This animal was completely stressed with sea gulls on the back and with a longline along the body, not only the driftnet, so at first we decided to take off the longline, then we started to take off the net around the head.

    From the upper part of the head it was more or less easy, but it was extremely difficult to take it off from the lower jaw, there were several loops of driftnet around the lower jaw, completely inside the teeth, it was really horrible.

    Then it was necessary to go inside the mouth and try and cut the net. It was the only way to cut it between one tooth and another. I personally touch the sperm whale and try and communicate... It was sort of a personal feeling between him and me and it was very strange. It was really an insecure operation, it was strange, he opened the jaw and let me work inside the mouth, my hands inside. I cut the first part of the net and it was extremely painful for this animal to stay there. So, he changed completely the sonic advice, moving from the usual clicks to this huge loud sound like a big 'clang' covering a huge range of Hertz, so it was impossible for me to stay there and even for the military divers to stay close to the animal. It was a strange impression feeling the position of our internal organs due to the vibration; it was really a difficult situation for us.

    We moved away from the mouth and then he closed the mouth, continuing the loud sound for about 30 seconds and the sound was so loud it was possible to hear it from outside the water onboard the patrol vessel. Then he returned again to the (regular) clicks, opened the mouth again and I went inside again. This fact happened three times then at the end it was possible to cut of all the driftnet from the mouth, then we started with the tail.

    Then we had the animal staying with us for another two hours close to the patrol vessel, then we forced him to leave otherwise it was a problem for him.

    It was a marvelous experience like several others but this one in particular. I suspect this is the only experience like that around the world."

I asked Dr. Di Natale whether he thought the animal new he was trying to help it?

LatestPhoto
Dr. Di Natale is seen here cutting the net from the lower jaw. A 2004 assessment report submitted to the International Union for the Conservation of Nature (IUCN) stated that - 'the main known cause of sperm whale decline in the Mediterranean is bycatch in high-seas swordfish driftnets, which has caused high levels of mortality since the mid-1980s'.
Photo Courtesy of Dr. Antonio Di Natale

Dr. Anotonio Di Natale -

    "That is for sure on that occasion. On other occasions, sometimes the animals were so stressed it was difficult for them to accept the presence of a human fellow close to them, so we have to wait a few hours before acting, before we rescue the animals.

    But in any case, it is always possible to be successful in this kind of operation. But you need a very good feeling with the animal and you need to respect the animal and then you need a good team."

The current lack of enforcement often means Dr. Di Natale and his team are the only hope of survival for an entangled sperm whale in Italy. The Centro Studi Cetacei goes a long way in reducing the mortality rate of entangled sperm whales. However, this is not a long term solution as it only covers entanglements that are reported and rarely assists those animals unfortunate enough to be entangled outside Italy.

Despite international and national regulation banning driftnets from the Mediterranean, driftnetting continues today in sperm whale habitat, thereby continuing to threaten the species' survival in the region. According to the recent IUCN report - "The virtual disappearance of sperm whales in the stranding record of France and their sharp decline in the records from Spain and Italy, despite a clear improvement in stranding reportage and investigation in all three countries, is seen as indicative of the species' decline in these waters, particularly in view of the fact that driftnet fishing continues.'

References

  • Consultation and Peer Review: SPERM WHALE, Physeter macrocephalus (= catodon): Mediterranean subpopulation Endangered.
    Drafted by Giuseppe Notarbartolo di Sciara and Alexandros Frantzis, in consultation with Giovanni Bearzi, Ana Ca–adas, A. Rus Hoelzel, Randall R. Reeves, and Hal Whitehead. It was reviewed by the CSG membership prior to submission to IUCN. Year Assessed: 2004

Links:

Log written by Genevieve Johnson.

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