Best! Day! EVER! – An Awe-Inspiring Day In The Field.

So every single day feels special and amazing when I get to be on the water researching killer whales! However, yesterday we had the day to top all days, the day that was better than any other day I have ever experienced on or off the water, potentially the best day of my life (too much…I think not!).

We had the most amazingly large pod of killer whales swimming in a long (slightly dispersed) line ahead of us 15-20+ individuals it was breathtaking, there was a mix of bulls, calfs, females and sub-adult males. It was mind blowing, I had tingles all over and felt so lucky to be in the presence of such an awe-inspiring sight. It truly took my breath away.

Six Individuals Surfacing To Breathe. A Snapshot From Our Large Pod Encounter!

But that ladies and gentlemen wasn’t even the best part. Just when we thought the best day of our lives couldn’t get any better we had a new encounter, something we had never seen before, a pod with a bull, three falcate fins (females or sub-adult males) and….FIVE, yes five, calves! What was going on? Was this an offshoot of the bigger pod like a nursery or creche for the calves? We don’t know, though that seems like one possible explanation. But boy do we want to find out more about this interesting pod composition. Let’s hope we get a repeat encounter before the season is over.

Three Of The Calves In The Pod Surfacing Together.

The soundtrap which, I discussed last week was out during this whole encounter so *fingers crossed* we have got some interesting acoustics to  analyse from this very interesting pod composition. We will know once we get back to Perth and take the many hours to sit down and go through the hours of acoustic recordings from the soundtrap while also reading the spectrograms to ensure we don’t miss any faint calls that require amplification.

In Sync! Look At Their Beautiful Light Grey Saddle Patches.

Many thanks to Naturaliste Charters and Riggs Australia for allowing us space on their vessels. Further thanks to the Centre for Marine Science and Technology at Curtin University for equipment loan and support.

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You can also follow along on the Deep Blue Conversations Facebook Page. I post interesting articles related to marine conservation, share awesome stories as well as photos from the marine conservation and environmental world in general. Come on over and have a look!

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She Just Came To Say Hello!

This individual popped up next to the boat yesterday afternoon. We had an absolutely amazing day on the water we were surrounded by a very large pod of long finned pilot whales at one point and then later the killer whales showed us some spectacular tail slapping behaviour. It was a great way to start the week!

Here is too a great second week in the field!

Many thanks to Naturaliste Charters for contributing to our research and allowing us space on their vessels. Further thanks to the Centre for Marine Science and Technology at Curtin University and the Busch Gardens Conservation Fund.

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You can also follow along on the Deep Blue Conversations Facebook Page. I post interesting articles related to marine conservation, share awesome stories as well as photos from the marine conservation and environmental world in general. Come on over and have a look!

It’s A Killer Whale World Out There!

Wow, Wow, Wow! It has been a busy few weeks since I arrive in Perth. First it was non-stop preparing equipment and organising ourselves and then it was diving head first into Bremer Bay life and data collection. We arrived in Bremer Bay in Western Australia on the 8th February and were out on the water 7.30 am on the 9th.

We are here to collect data on this unique aggregation of killer whales (Orcinus orca) that occurs every year between January and March a 2 hour steam offshore from Bremer Bay where the water depth drops quickly from around 80 metres to over 800 metres and deeper. Here there are numerous underwater canyons where the depth can reach 3000 metres or more.

Now back to the cetaceans…So very little is known about the Australian killer whale population and we hope to be able to change this by building up a picture of where they are, and what they are doing, while also deciphering the individuals we are seeing through fin identification and using hydrophones to determine their acoustic repertoire. It is an amazing project.

On the 10th February we deployed two noise loggers which, are long term underwater recording devices that record on a schedule and allow us to build a picture of what is happening when we are not there through the acoustics of the region. From these we will be able to build a picture of natural ocean noise such as waves, wind and, marine mammals as well as anthropogenic noise from boats and far off seismic activity.

Alongside, the data collection on marine mammals we also plan to use a mounted sonar to record the biomass in the region especially when marine mammals are feeding and a CDT (Conductivity, Depth and Temperature) instrument to record salinity, depth, temperature as well as fluorescence to gain a better understanding of what makes the ecosystem work. Further, to all this amazing equipment we have also had sonobuoys donated to us by L3 which, will allow us to passively and in real-time monitor the acoustic environment while we are at sea. This will in theory enable us to hear what is happening underwater while we see what is happening above water and potentially determine what we are missing as well as what is happening (acoustically) up to 5 km away.

We are only just getting started on this project but, from it I hope to be able to build up a PhD thesis that I can really get excited about. Alongside killer whales there have been sightings of beaked whales, sperm whales and pilot whales in pervious seasons. Just yesterday we spotted a pod of between 20 and 30 long-finned pilot whales (Globicephala melas) where it looked like the sea was bubbling with activity. I cannot wait to see what tomorrow brings.

A bubbling sea of long finned pilot whales.

We had a windy day off today where we tried to catch up on some data, visited the beautiful remote beaches of Western Australia and do all our laundry which, was nice especially as we don’t know when we might get another day for data catch up!

I will try and upload some video footage and updates from the field as our crazy hectic time here in Bremer Bay flies back.

Many thanks to Naturaliste Charters and Riggs Australia for contributing to our research and allowing us space on their vessels.

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You can also follow along on the Deep Blue Conversations Facebook Page. I post interesting articles related to marine conservation, share awesome stories as well as photos from the marine conservation and environmental world in general. Come on over and have a look!

Porpoise Killing Seals…Dramatic New Behaviour!

Scientists have discovered through DNA analysis that harbour porpoises (Phocoena phocoena) that have washed up severely mutilated and dead along the Dutch as well as the Belgian and northern France coastline beaches with an unknown cause of death and mutilation were actually attacked by grey seals (Halichoerus grypus). This is a new behaviour for the normally fish eating mammals.

Grey Seal. Image via http://www.theanimalfiles.com

Two different papers came out this past month (Leopold et al and Jauniaux et al) confirming this behaviour in the North Sea though DNA analysis (as well as a Note in Marine Ecology Progress Series on the ability to extract usable DNA from bite wounds). By collecting swab samples from bite marks on washed up harbour porpoises scientist were able to confirm that the injuries and death had been inflicted by Grey Seals.  Along the Dutch coastline 721 of 1,081 stranded porpoises were examined by Leopold et al between 2003 and 2013 of these at least 17% were subject to attack by grey seals. If we take into account that individuals with larger wounds would have sunk without recovery and that some porpoises may have escaped attack and later died from wounds this number may be much higher and mean that seal attacks are a significant contributor to harbour porpoise death in the North Sea alongside fisheries bycatch (approx. 20%), infectious disease (approx. 18%) and emaciation (approx. 14%).

The Jauniaux et al study along the French and Belgian coastline the scientists instead looked at five stranded porpoises with bite-like skin lesions which they swabbed for genetic material. They used these to confirm that even after several days in seawater genetic material of grey seals can be recovered from wounds and that bite-like skin lesions found on the dead porpoises is definitely the result of grey seals attacks. It was also found that some wounds (puncture) from grey seal attacks more readily retain genetic material than others (lacerations).

Scroll down to the bottom to see some of the rather graphic images of mutilated porpoises.

So how, when, why, where did this all start?!?

These are all very good questions and it will be hard for scientists to come up with a definitive answer for all of them. Leopold et al speculate that grey seals could have progressed from opportunistically feeding on harbour porpoise that had become entangled in fishing gear to full on attacking them as prey. The first confirmed victim of a grey seal attack washed up in 2003 and between then and 2013 the number of mutilated carcasses increased the authors states that there would

have to have been the perfect set of prerequisite in place for this to have come to be:

“These include sympatry of predator and prey, and possibly a high incidence of fisheries bycatch of the prey in static fishing nets to induce this behaviour.”

The study by Jauniaux et al even used the head of a recently dead grey seal to mimic bite-like skin injuries on a porpoise carcass to confirm seal DNA transfer. They believe that the injuries are likely from predation although cases of aggressive behaviour can not be ruled out for all attacks.

So what does this mean for harbour porpoises?