Join me in the cold, dark, life-sustaining NE Pacific Ocean to discover the great beauty, mystery and fragility hidden there.

Posts from the ‘Sea Lions’ category

The Case of Stones in Sea Lions’ Stomachs

Did you know that stones are commonly found in the stomachs of Steller sea lions?

These stomach stones or “gastroliths” are as big as 12 cm!

Share your theories about why you think this might be after viewing the video below. It provides you with information to help with this Marine Detective case.

Happy sleuthing to you!


Click here for SeaDoc footage of Steller Sea Lions playing with California Sea Cucumbers.

Research into gastroliths in Steller Sea Lion

C. R. Shuert and J. E. Mellish “Size, mass, and occurrence of gastroliths in juvenile Steller sea lions (Eumetopias jubatus),” Journal of Mammalogy 97(2), 639-643, (11 January 2016).

Includes: “In summary, our opportunistic assessment of gastroliths in temporarily captive Steller sea lions showed that a large proportion of juvenile animals (e.g., one-third or more) may haveone or more stones at any given time. The regurgitation of gastroliths correlated best with leaner, but not poorer body conditions, and during the summer months, possibly indicating a weak association as a digestion aid. We found little evidence to suggest that they assist in buoyancy and satiation; it is even more unclear as to what drives an individual to regurgitate them. With a lack of strong conclusions relating to a particular use, we can only conclude that they appear to serve a function in sea lions and are not ingested accidentally. A combined assessment of regurgitated and in vivo gastrolith measurements may shed more light on the subject and allow for direct evaluation and conclusions as to their functionality in sea lions.”

Kaouk the Sea Lion – The Story Gets Better and Better!

Update to the April/May information below: June 16, 2011.

From Peter Olesiuk, DFO –  “I have not heard anything from Kaouk for over 2 days now, and I suspect his tag may have been moulted.  In our Steller studies the tags tended to fall off in July-August.  However, I checked the literature and the moult is 1-1/2 months earlier in juveniles, typically starting on 21 June.  In my experience, tags glued to the pelage [fur] tend to fall off when the hair follicles weaken early in or just before the actual moult.”


A picture is definitely worth a thousand words. See below for April 14th and May 8th images of Kaouk the Steller sea lion healthy, fat, WILD and with his peers!!

This photos and information has been provided by lighthouse keeper Jerry Etzkorn, via DFO and the Vancouver Aquarium’s Marine Mammal Rescue Centre (you can follow MMR on Facebook at this link).  

Kaouk, is the male Steller sea lion that walked into the Port Alice trailer park on December 16th and was flown to the Vancouver Aquarium’s Marine Mammal Rescue Centre. He inspired the students of Port Alice to write a children’s book and was released back into the wild on March 17th from southwestern Vancouver Island.

For background information on Kaouk, including how you can follow him via satellite tag, click this link for a previous blog posting.  

Click the images to see them at a larger size.

Another happy Kaouk update from May 8th, 2011. Thank you Peter Olesiuk.

Photo taken on April 14, 2011 by Carmanah lighthouse keeper Jerry Etzkorn. He reports “He is certainty active and definitely accepted and tuned in to the other sea lions.”

Kaouk – The Next Chapter of “The Steller Sea Lion That Flew”!

[Updates up to April 6th provided below. For more recent updates – including a photo of Kaouk hauled out with other wild Steller sea lions, click here. 

Kaouk bounding unhesitatingly back into the wild. Where is he now? See links below for links to the Vancouver Aquarium announcement and track data. Photo is a video grab by Peter Olesiuk (DFO)

Kaouk was released back into the wild on March 17th, from Toquart Bay on southwestern Vancouver Island (where the herring are bountiful) and  . . . now you can follow his progress!

Kaouk, is the male Steller sea lion that walked into the Port Alice trailer park on December 16th and was flown to the Vancouver Aquarium’s Marine Mammal Rescue Centre. He inspired the students of Port Alice to write a children’s book and will no doubt continue to be a charismatic marine ambassador to we humans; helping us understand his species, when to help wild animals, ad when to leave them be.

For the Vancouver Aquarium’s announcement of his release click here.

The announcement includes the link to where you can follow him via a satellite tag that was attached to Kaouk’s fur with epoxy and will fall off when he moults.

Click here for the direct link to the tracking data.

Click here for a previous blog posting giving background on Kaouk.

And click here for a 1-minute video of his enthusiastic return to the wild, made available by Peter Olesiuk (DFO).

Kaouks wanderings to the morning of April 6, 2011. He has been exploring and hauling out a lot. See text for update.

Update April 6th, 2011.

See the image below – Kaouk has been exploring Barkley Sound and hauling out on a regular basis over the last 10 days, first at Mara Rocks (the largest and only year-round Steller haulout in Barkley Sound – see previous update) and more recently at Wouwer Island (a winter haulout occupied by Steller and California sea lions mainly outside of the May-August breeding season).  He has been frequenting areas knowing to be good herring spawn areas, and areas known to have concentrations of sardines).  Go Kaouk go – eat lots!  Scientist Peter Olesiuk of DFO reports that he needs to eat 15-20 kg per day, which is apparently a challenge. Scientist Peter Olesiuk of DFO reports that about 46% of sea lions don’t make it through their first year.

Click to enlarge. Mara Rock - the Steller sea lion haul out that Kaouk has been frequenting! Image provided by Peter Olesiuk (DFO).

Update March 30th, 2011

Kaouk is with his own kind!

Since the evening of March 25th, he has been hauling out and foraging around this haulout on Mara Rock. Peter Olesiuk of DFO kindly shared that Mara Rock is the largest Steller sea lion haulout in Barkley Sound and that it is the only site that is occupied year-round (600+ animals, including lots of juveniles like Kaouk, at this time of year). Images below provided by Peter Olesiuk show the Mara Rock haulout and, in the satellite tracking image, Mara Rock is in the bottom left corner (note how consistently he has been at this site). Most of his dives are reported to be between 20 to 50 m with a few in the 50 to 100 m range.

Click to enlarge. Satellite image from AM of March 30th. Note the concentrated activity in the bottom left of the image. This is Mara Rock - a large Steller sea lion haulout!!!

Update March 19th: If you have been looking at the satellite data for Kaouk, please note that the locations are only updated once a day (data is not real-time) and that locations are not very “refined”. The map below (provided via Marine Mammal Rescue) gives a far more accurate look at Kaouk’s adventures. It looks like he hasn’t even come ashore in his first days in the wild! He has been actively diving and hopefully filling himself up with herring.

Kaouk - March 17th to +/- 09:00 March 19th. Image via Vancouver Aquarium Marine Mammal Rescue.

Steller visits!

Screen grab from Steller encounter 2011-02-12

Screen grab from the video.

While diving yesterday, we had a visitation from two juvenile Steller sea lions.

I’ve put a 1-minute clip of the encounter on-line, in a gallery with other videos of when these magnificent mammals have chosen to do a swim-by.

Note that I do not “target” marine mammals while diving (this is in fact stipulated as being illegal in Canada’s draft marine mammal regulations)  i.e. I do not jump in near sea lion haul-outs as I do not want to put pressure on the animals nor contribute to their becoming habituated to humans.

Therefore, when we see them there is always an element of surprise and, of course, extreme privilege.

See this link for the video clips.

See this link for a previous blog posting that includes the natural history of Steller sea lions.

Note: “Steller” is for the nautralist Georg William Steller who was doctor and naturalist on Vitus Bering’s second Kamchatka Expedition that also sailed to Alaska and the Commander Islands (1740 – 1741?).

Kaouk – The Steller Sea Lion That Flew

Kaouk at the Marine Mammal Rescue Centre. Photo: Hildering

Below, please find a link to a slide show update on Kaouk, the juvenile male Steller sea lion that walked into the Port Alice (BC, Canada) trailer park on December 16th, 2010.

I had the privilege of visiting Kaouk at the Vancouver Aquarium’s Marine Mammal Rescue Centre on January 20th and was amazed at the improvement in his health.  A decision will soon be made about his return to the wild.

See this link for the 3 minute slide show (available in two sizes for ease of viewing).

See this link for a background story in the North Island Gazette.

When Pilchard Return

Ms. Henderson’s students in Port Alice, B.C. put me onto a case yesterday.

They had me check what was happening in the beautiful inlet in front of their community on north-western Vancouver Island and – what a fabulously noisy case it was!

Pilchard (aka “Pacific sardines”; Sardinops sagax; up to about 40 cm) have brought in a whole food chain of activity:  fishing boats, hundreds of gulls, many Steller and California sea lions and, that’s just what we could see on the surface!  Pilchard were absent from the Pacific Northwest for about 50 years, having been very intensely fished into the early 1940s. With their return, our Coast has become much more vibrant with these fish fuelling a food web that includes humpback whales and both the Steller and California sea lions.

Steller sea lions - male on right. Image: Uko Gorter Natural History Illustration.


Having male Steller sea lions (Eumetopias jubatus) in our area is common. These giants (mature males up to 1,100 kg and 3.3 m) are the lighter coloured of the area’s two sea lion species.

In the last 7 years or so, we have also had some male California sea lion males (Zalophus californianus) around Northern Vancouver Island from the Fall into the Spring but they are far more common to the South.

California sea lions - male on right. Image: Uko Gorter Natural History Illustration.


The California sea lions are the darker and much smaller sea lion species (mature males to 390 kg and 2.4 m). The mature males have distinct light colouration on parts of their head and a very unique shape to their foreheads. However, beyond these very apparent physical differences, you could be blind and still tell California sea lions and Steller sea lions apart! California sea lions bark. Steller sea lions growl.

The sea lion activity I witnessed yesterday is really unique and all thanks to the return of the pilchard. I have never seen this many California sea lions anywhere around northern Vancouver Island and it is not often that I have seen mixed groups of both species hunting together. I checked with the locals in Port Alice and no one can recall ever seeing this many California sea lions in Neroutsos Inlet.

This phenomena has fortunately been captured on video for you to enjoy (video from the Village of Port Alice).  See below and look very carefully for the lighter coloured Steller sea lions among the barking Californians!  All these sea lions are likely to all be male. The smaller ones are the immature males.

Great thanks to the students of Seaview Elementary for caring and knowing as much as they do.  Psst, I would be watching the water very carefully because this pilchard driven food chain has transient killer whales at its top!


For locals: Added January 3rd, 2011

Update on the sea lion that crossed the road and entered the Port Alice trailer park on Dec 16th. Because he appeared to be underweight and lethargic, he was taken to the Vancouver Aquarium’s Marine Mammal Rescue Centre on Dec 18th (I think). It is a male Steller sea lion and was confirmed to be malnourished and dehydrated with no indication of what may have caused his condition. He has been named “Kaouk” after a mountain near Fair Harbour.

My great respect to the people of Port Alice for knowing to call DFO’s marine mammal response line (1-800-465-4336) and have the RCMP conduct crowd control. Ms. Henderson’s class even had made up info brochures on how to best behave around the sea lions.

Come Away With Me

Come on. You know you want to, just for 3 minutes.

Come on the dives I did today.

The little slide show I have put together, is a testimony to the grand, jaw-dropping biodiversity of this area (Northern Vancouver Island, B,C., CANADA).

The Minke whale we saw, the fish using a sponge as a hammock, the bald eagle chick that took one of its first flights – all these are animals that I have learned from by knowing a small part of the world’s ocean well enough to be able to recognize individual animals.

Such a privilege and such a joy to share with you.

Come away with me . . . . click here.

California Sea Lions Barking Underwater – video!

This posting is typical for why I set up this blog (and the identity of “The Marine Detective”). I want to share what I learn from my marine adventures.

I was diving off Northern Vancouver Island when my buddy and I had a “swim-by” from several male California Sea Lions and one male Steller Sea Lion. 

Many of you know that the two species can be discerned very easily because California Sea Lions bark and Steller Sea Lions growl. Yep, you could  be blind and determine which sea lions species is present. 

You can’t miss the barking of California Sea Lions when they are on land. 

What I hadn’t fully realized was . . . you can hear them bark underwater too!

See my video below./strong>

Please note that it is against my ethics (and the law) to target seal and sea lion haulouts for the purposes of diving with them. This certainly constitutes “disturbance” of marine mammals and also leads to the animals losing their wariness and becoming habituated to humans. This has led to significant human injury. It definitely does not help the seals and sea lions either to be habituated to people as there are those who believe there are “too many” and that they should be killed. 

However, sometimes, as a result of being in their ocean, we have unexpected encounters like the one videoed here.

Update 2018: The amended Marine Mammal Regulations (federal law) now specifically include: “No person shall approach a marine mammal to, or to attempt to: (b) swim with it or interact with it.”