Our project description/Digital story of the depredation.
Swirl
Sunday, October 2, 2016
Sunday, August 14, 2016
End of the second season.
The second part of
the Greenland Halibut season was an intense two-week period with many
whale sightings and the fishermen proved again to be a great asset in
gathering data.
Fishermen of M/S Egilson
Tiu joined the fishermen of M/S Egilson to see the depredation for
herself. As fate would have it, that particular boat caught a halibut
with spermwhale toothmarks on it. Our research team will now reside
to analyze the data, make trials with the underwater acoustic array
and plan our future moves.
Thank You all!
A spermwhale diving to have a feed off the longlines.
Spermwhale toothrakes on a Greenland Halibut.
Sunday, July 31, 2016
Second season beginning.
The second part of
the Greenland Halibut season has now commenced and we are on location
in Stø continuing the research. The winds are high keeping the
fishing boats in harbour, which has given us time to calibrate our
acoustic gear and set up the foundations.
Our fisherman friend, Paavo Pirttilehto at his trade.
We have acquired a
great help from fellow colleague and scientific mind Jonathan Gordon,
whom Fred went to visit in S:t Andrews, Scotland. Jonathan supplied
us with the latest technology in underwater acoustics and we are very
grateful for this collaboration. Thank You Jonathan!
Dr. Jonathan Gordon assembling a hydrophone kit for us.
Tuesday, June 14, 2016
End of first quota
The Greenland Halibut fishing has
ceased for a six week period and will commence again on July 25th.
The increase in sightings of spermwhale depredation behaviour in our study area increased dramatically during the last week of the fishery. The escalation made headline news in the Norwegian media (here). The whales were foraging up to 50% of the catch in the most
recent encounters.
Fishing grounds of Vesterålen. Maps created using OpenSeaMap
The solution to this situation is not
arriving in a hurry and as for now, we will analyze the collected
data (identity and numbers of sperm whales, summary of number and location of depredation events, estimates of catch loss). Thanks to fishermen and whale-watch operations and the owners of MV "Brandaris" we have a wealth of information. We are hoping to have some ideas for solutions that we could try out already in the next fishing season. Our longterm plan is to create a larger project that includes scientists who have worked with depredation in other parts of the world and together with fishermen try to find good mitigation solutions to the problem.
We are very grateful to all those who have contributed to our work so far. It has been an exciting three weeks and we are surprised to find the scale this problem has escalated to in such a short time. We are looking forward to our new field season starting in late July and in the mean time update the log with our findings so far.
Sperm whale diving to the longline of "Egilsson"
The project has got quite a lot of media coverage the past weeks, which has proven useful. We have received more information from fishermen participating in longline fishery, including reports dating back 30 years (!) of sperm whales depredating from the lines. The older reports from Norwegian coastal waters are all further north of our study area, in fishing grounds called "Tromsøflaket". In this area majority of fishing vessels are much larger, automatic longliners than the smaller fleet we have cooperated with off Vesterålen islands (in Langenesegga). We are not sure why depredation events have not previously been reported from Tromsøflaket (and when we asked the fishermens union in april about possible depredation in these waters the reply was "no whales have been observed around longliners"). The lack of reports could, sadly enough, represent
the ever growing gap between fishermen and scientists. However, now we know
that we should expand our study area and get cooperation going on with this
fleet as well.
The fishing grouds of Tromsøflaket.
11th og June sperm whales were taking fish from longlines on a fishing ground (Hesteskoen)further
south towards the Lofoten islands, and the fishermen who reported this told
me they have not seen this behavior before – so yes, depredation behavior is
spreading.
Our "main operator", seen around longliners in Langenesegga since 2014
We are very grateful to all those who have contributed to our work so far. It has been an exciting three weeks and we are surprised to find the scale this problem has escalated to in such a short time. We are looking forward to our new field season starting in late July and in the mean time update the log with our findings so far.
Tiu and Tom assessing the situation.
Wednesday, June 8, 2016
Depredation update
The longline fishery off Vesterålen has now taken place for a bit over two weeks (started 23/5).The area where interactions between sperm whales and fishery are observed is an approximately 20 km long and 2km wide "stretch" of the continental slope around 600 m depth. This area is fished by boats leaving mainly from the harbours of Stø and Nordmela, and the fishermen staying in these harbours have proven to be valuable collaborators providing us with observations and even video- and ID images! We have also obtained ID images and other data from august 2014, when this behavior was first observed. Thank you to all skippers!!
Photo by Jesper Persson.
Photo by Erik Heiskanen.
Here are two images of whales identified in June feeding from a longline. We are in the process of organising and updating the long term photoidentification data set collected onboard whalesafari boats operating from Andenes (pictures dating back to 1989) and will check if these two whales have been sighted before. We know that one of the "main operators" from August 2014 is a whale that has been identified for more than a decade in these waters.
We have seven confirmed depredation events, and there are still several fishermen from Nordmela we have not interviewed yet. So yes, the whales are defnitely taking Greenland Halibut from the longlines. We have realised that fishermen are not always aware of when depredation events take place, a rather common description has been: "The whale(s) was just floating around the boat, not feeding". This is due to the fact that when the sperm whale dives under the boat and starts feeding, this is not observed other than as fish lacking from the line (there is no "tugging" or other visible behaviors). On some occasions the fishermen have filmed whales that are swimming towards the boat, lifting their head as if to "precision target" to where the boat and the fish are.
Our next step is to try to get sound recordings of the sound the boat makes when they start taking up the line. According to research done elsewhere, it is this sound that alerts the whales to presence of fish. However, several fishermen have also reported that the whales start "waiting" as soon as they have set the line and can swim around the boats for several hours, waiting that the line is being taken up, so we are thinking of recording sounds of the whole fishing operation.
Ideally we will also be able to record the sounds made by sperm whales when they are taking fish from the lines. In future, acoustic monitoring might be an additional method in getting an estimate on how often depredation takes place.
The longline fishery off Vesterålen has now taken place for a bit over two weeks (started 23/5).The area where interactions between sperm whales and fishery are observed is an approximately 20 km long and 2km wide "stretch" of the continental slope around 600 m depth. This area is fished by boats leaving mainly from the harbours of Stø and Nordmela, and the fishermen staying in these harbours have proven to be valuable collaborators providing us with observations and even video- and ID images! We have also obtained ID images and other data from august 2014, when this behavior was first observed. Thank you to all skippers!!
Here are two images of whales identified in June feeding from a longline. We are in the process of organising and updating the long term photoidentification data set collected onboard whalesafari boats operating from Andenes (pictures dating back to 1989) and will check if these two whales have been sighted before. We know that one of the "main operators" from August 2014 is a whale that has been identified for more than a decade in these waters.
We have seven confirmed depredation events, and there are still several fishermen from Nordmela we have not interviewed yet. So yes, the whales are defnitely taking Greenland Halibut from the longlines. We have realised that fishermen are not always aware of when depredation events take place, a rather common description has been: "The whale(s) was just floating around the boat, not feeding". This is due to the fact that when the sperm whale dives under the boat and starts feeding, this is not observed other than as fish lacking from the line (there is no "tugging" or other visible behaviors). On some occasions the fishermen have filmed whales that are swimming towards the boat, lifting their head as if to "precision target" to where the boat and the fish are.
Our next step is to try to get sound recordings of the sound the boat makes when they start taking up the line. According to research done elsewhere, it is this sound that alerts the whales to presence of fish. However, several fishermen have also reported that the whales start "waiting" as soon as they have set the line and can swim around the boats for several hours, waiting that the line is being taken up, so we are thinking of recording sounds of the whole fishing operation.
Ideally we will also be able to record the sounds made by sperm whales when they are taking fish from the lines. In future, acoustic monitoring might be an additional method in getting an estimate on how often depredation takes place.
Further investigations
The longline fishermen have had several encounters with spermwhales during the last week or so. We spent the day speaking with the fishermen of Stø.
Lauri Pietikäinen (on the right) with the fishermen of M/S Havgull.
Lauri Pietikäinen (on the right) with the fishermen of M/S Havgull.
Tuesday, June 7, 2016
A day with Jacquelyne
Yesterday our team member Fred joined Arctic Whale Tours on a whale safari. The day was a success with multiple sightings and underwater recordings of spermwhales. Thank you Arctic Whale Tours crew.
M/Y Jacquelyne ready for departure.
Under way to where the whales are.
One of five spermwhales that we saw during the safari.
M/Y Jacquelyne ready for departure.
Under way to where the whales are.
One of five spermwhales that we saw during the safari.
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