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

Posts from the ‘FISH – NE Pacific Ocean’ category

Sharks Among Us #2 – The Bluntnose Sixgill Shark

[Update February 2019 – Another pregnant female Bluntnose Sixgill Shark has been found – February 5th, in Coles Bay, North Saanich, southern Vancouver Island, British Columbia. Original blog about a pregnant female found in 2011 follows after the first two photos.]

Photo #1: Dead pregnant Bluntnose Sixgill Shark, found  – Coles Bay, February 5th, 2019 ©Ron DeVries.

Photo #2: Dead pregnant Bluntnose Sixgill Shark, found  – Coles Bay, February 5th, 2019 ©Ron DeVries.


Original blog:

The awe-inspiring images below are of a pregnant female Bluntnose Sixgill Shark (Hexanchu griseus) that was found dead on a beach in Alberni Inlet on low tide in February of 2011. She was necropsied by Department of Fisheries and Oceans staff and there were no obvious indications of how or why she died.

The information has been generously shared by federal shark biologist with the Pacific Biological Station, Romney McPhie. 

4.2 m pregnant female Sixgill Shark – February 2011.

This female Sixgill was 4.2 metres and was estimated to weigh 569 kg (1254 lbs).  As a viviparous shark species, she carried her embryos through the entire 12 to 24 month gestation period (species does not lay eggs / egg cases).  She may have given birth to some prior to her death and still had 28 pups inside her.  If she did indeed give birth, these pups would likely survive.

Sixgill Sharks have been reported to be up to 4.8 metres in length with females being larger than males (females to 4.8 m and males to 3.5 m).Age fo sexual maturity is estimated to be between age 11 to 14 for males and between 18 to 35 years for females. It is believed that life expectancy may be up to 80 years of age. 

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) 2007 assessment report on the Bluntnose Sixgill puts into perspective how rare an opportunity it is to learn about a pregnant Sixgill.  It relates that the number of pups carried by females is known from only three previous credible accounts (ranging from 47 to 108 pups which are 61 to 73 cm in size).

The Bluntnose Sixgill Shark is an extremely cryptic species that can dwell at depts up to 2,500 m.  So little is known about them and (sigh)  they are “near threatened” globally and are a species of “special concern” in Canada.

I have had the incredible privilege of seeing a Bluntnose Sixgill Shark while diving and felt like I was in the presence of greatness. They are living fossils, perfected by 200 million years of adaptation. They are amazingly graceful with large, luminous and intensely green eyes.

They are of absolutely no threat to humans and, like all sharks, have an essential role in marine ecosystems.  As top-level predators, sharks strongly shape food webs and the loss of such predators has proven to have profound effects on the number and diversity of other species.

The unique teeth of Bluntnose Sixgill Sharks. Photo by Romney McPhie.

We however are a threat to them.  It is reported that in just three years (2006 to 2009), 1,341 Sixgills were bycatch in longline fisheries. There is no information on the survival rates from bycatch nor is population size and reproductive rate known for this species.

Please read more about the biology, threats and conservation of Bluntnose Sixgill Sharks:

  • Government of Canada Management Plan for the Bluntnose sixgill shark (Hexanchus griseus) and tope shark (Galeorhinus galeus) at this link. 
  • Species at Risk Public Registry at this link.

Sixgill Shark eye. This one died as a result of longline bycatch and was brought into Alert Bay in July of 2007. It was rumoured to be one of 12 sharks caught by only one local fishing boat. Photo: Jared Towers.

 

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.


Kelp Greenling Colour and Courtship

While diving this morning, I came across a kelp greenling couple while they were courting (Hexagrammos decagrammus to 60 cm).

In addition to being fascinated by the courtship behaviour, I was struck by the intense colouration, especially of the courting male.

Male kelp greenling. Normal colouration. ©2013 Jackie Hildering

Male kelp greenling. Normal colouration. ©Jackie Hildering

Mature male and female kelp greenlings look very different but I had never fully realized how the males’ gender specific colour intensifies during courtship.
Their bodies become much paler while the heads remain dark blue.

Courting male on left (note how much lighter the body is than the head); female on the right. © 2013 Jackie Hildering

Courting male on left (note how much lighter the body is than the head); female on the right. ©Jackie Hildering

My 1.5 minute video below shows the courtship behaviour. After that there is a photo of eyed kelp greenling eggs.

Kelp greenling eggs in a giant barnacle shell. See the eyes?! © 2013 Jackie Hildering

Kelp greenling eggs in a giant barnacle shell. See the eyes?! ©Jackie Hildering

Fish Forever – The Wisdom of a Nine-Year-Old

Nature gave us sockeye salmon this year. A red-scaled, bounding life source, some 34 million fish strong.

This has led to human voices shouting out in all from gratitude to greed; from delight to denial.

Predictably, sadly, there have been far too many who have been at the “greedy denial” end of the spectrum. I will not tire you with that here though.

I want to fish out two voices of sanity from the ocean of opinions. One voice is that of reporter Stephen Hume from the Vancouver Sun. The other is nine-year-old Avery Walker who I am privileged to have as a member of my Northern Vancouver Island Young Naturalists’ Club.

Stephen Hume, award-winning author,  in The Vancouver Sun: “Columnists who apparently wouldn’t know the difference between a sockeye and a sculpin cluck and scold in a Toronto newspaper. One enthusiastically advances the argument that we should whack 30 million of the 34 million returning salmon . . . . . Instead of permitting a lust for instant gratification to derail a natural process for rebuilding small stocks, now is the time for restraint, for harvest restraint is a critical investment in future abundance. So enjoy your sockeye. Be grateful for this gift from nature. But don’t let the gong show of greed sway us from good stewardship.”

Avery Walker - Salmon Superstar. Photo by Larry Walker and Anna Marchand.

Avery Walker, 9-year-old Young Naturalist, with his prize-winning submission to the Wild Salmon Circle’s “Spawning Ideas” contest: “I fish only with barbless hooks, I’ve taken all the treble hooks from the all the buzzbombs I have and replaced them with single barbless hooks. I don’t jig the fish, I fish the ones who bite. Sometimes this is really hard to do, because not all of my friends fish like this, and so they sometimes take home more fish than I do. I abide by the regulations about which salmon I can keep and which ones I can’t. I never go over my limit. Or keep undersized fish. Most of the time, I catch and release. I love to fish, and I want to be able to do it forever.”

Thank you Avery. Thank you Stephen. Thank you all who make choices that may allow us to have  . . . fish forever.

For insights into the need for precaution in managing the harvesting and threats to the Fraser River sockeye, please click here for information from “Save Our Salmon”.

Sharks Among Us #1 – The Blue Shark

The image below is of a Pacific Blue Shark (Prionace glauca) being rescued by Lindsey Pattinson of Tiderip Grizzly Tours on July 15th, 2010 in Glendale Cove, British Columbia.

Lindsey Pattinson rescuing a blue shark. Photo: Nick and Sue Spiller. 

Many British Columbians are unaware that we have at least 13 species of shark among us, ranging from the smaller species such as the Spiny Dogfish up to the 6-gill shark (5 m+) and the very, very rare Basking Shark (9 m+). The beautiful Blue Shark reaches a maximum of 3.8 meters and is distinct in its deep blue colouration and slender shape.

The Slue Shark is common in B.C. and is, in fact, extremely far ranging and widespread. It is found from Alaska to Chile in the Pacific but is also present in the Atlantic and Indian Oceans.  It has been found in waters from 7 to 16°C, latitudes of 60°N to 50°S and from the shallows to depths of 350 m (being more often at depth in warmer waters).

In researching the species after Lindsey’s find, I discovered that Blue Sharks undertake very large migrations, reportedly up to 9,200 km, moving north in the summer months.  More females than males move to the higher latitudes.

But, of course a sighting like this in Glendale Cove is an enormous rarity. Even with the Blue Shark being common in B.C., they are more often oceanic, on the continental shelf . . . not on the beach in Glendale!

For whatever reason, the animal stranded there and Lindsey cared enough to do what he could to save it.  Many shark species need to keep swimming in order to have oxygen-rich water pass over their gills. Knowing this, Lindsey moved the stranded shark back and forth in the water, forcing water over its gills and indeed, he revived it. He and the tourists he was guiding on the Grizzly Bear (and shark) watching trip had the joy of watching the animal swim to depth.

Thanks to Lindsey, this Blue Shark will be able to have more days of feeding on anchovy, mackerel, salmon, hake, dogfish, crustaceans and squid. It may also scavenge here and there and even feed on aggregations of krill by straining the water in the way a baleen whale would.

I suspect the Glendale Cove shark was a female and with Blue Sharks being a very prolific species, now saved, she could go on to bear 25 to 50 pups at a time (apparently even as many as 135)!  These young would grow inside her as the blue shark is “viviparous”, meaning they bear fully formed young. The pups are 35 to 44 cm at birth.

I was fascinated to learn that blue shark females can apparently “get pregnant” up to 20 months AFTER mating. They can store sperm packets in special glands in their reproductive tract called “shell glands” (aka nidamental glands) and pass their eggs through these glands to get fertilized.

If the rescued Blue Shark was indeed female, she may not have been able to feel much of Lindsey’s caring touch since the females are up to 3 times thicker skinned that the males! This adaptation is believed to allow the females to deal with the males since there is a lot of biting during courtship.

Unfortunately, the fate of Blue Sharks can also be to become the bycatch of longline and driftnet fisheries. One source reported that in one year alone (1990) “it is conservatively estimated that by-catch of blue sharks taken by the Japanese squid fleet in the North Pacific totalled 700,000.”

Further life history: Males sexually mature at 4–6 and females at 5–7 years. Believed to live to age 20.

For more photos of the blue shark rescue, click here.

Great thanks to Nick and Sue Spiller for sharing these photos.

Sources include:

It’s Raining Fish?!

Juvenile yellow-tail rockfish.

Recently, I noticed a lot of splashing in a tideline off Telegraph Cove, BC. I share my observations with you via the little video clip at the link below.

You’ll note that it looks like big rain drops are hitting the water.

I discovered that what was creating the splashing were juvenile yellow-tail rockfish feeding on zooplankton. The zooplankton, including a small species of krill, had been concentrated at the surface by the big tidal exchange. There had been almost a 4 metre exchange between high and low tide (more than 12 feet).

I also discovered a very unique larval fish in the tideline that day but will share that discovery in a future “The Marine Detective”.

Click here for the video of the yellow-tail rockfish feeding in the tideline.

Enjoy!

Who’s Your Daddy?

Scalyhead Sculpins are a tiny fish but the males have a giant parenting role (species Artedius harringtoni).

I found what I believe were this species’ eggs while guiding a recent beach study (Port Hardy, BC).

To share this information, and my photos, I’ve tried something new. Below, you’ll find a slideshow that I have narrated to explain how Scalyhead Sculpins are super dads.

Yes, that’s right, you get to hear my voice this week (oh-so-human stumbled speech and all!). Please realize I am speaking as I would to a +/- 10 year old.

Manta Ray Magic – Fiji


In December of 2009, I had the extraordinary privilege of seeing manta rays while diving off Kaduva Island with the dive crew from the Matava Eco-Resort. It is thanks to the environmental ethic of this team that these dives are very controlled to make sure the animals are disturbed as little as possible.

The video allows us to share all the observations listed below as well as giving you the chance to laugh when you hear my underwater screams of joy when the mantas break from their feeding behaviour, get into a formation of 5 animals and swim by us 4 times!  I didn’t even realize I was making these sounds but my dive buddy was there behind me, capturing it on video.

 

The video shows:

  • Holy manta rays are big!  They are the biggest rays in fact; up to almost 7 m across and more than 1,000 kg.  The ones we saw are probably about 4 m across.
  • They are very “alien” looking animals.  They feed on plankton and small fish and can scoop more food using the two big paddle-shaped flaps (“cephalic lobes”) that are just to the inside of their eyes. You will see from the murkiness of the water that it is thick with plankton.  The circular diving pattern of the mantas is believed to help them concentrate the plankton.
  • That manta rays have a relatively short tail for a ray, no stinging spine and you’ll see one animal in the video that has had their tail shredded off, likely by a tiger shark.
  • That sometimes there are remoras attached to the manta rays. These fish may help in removing parasites and have the benefit of transportation, being less visible to predators and possibly getting some scraps as snacks.
  • That mantas are incredibly graceful, having very flattened bodies and big wing-like fins.
  • They can be told apart as individuals. Of course the one with the shark injury is easy to tell apart from the others. There is also one that has had its left fin tip bitten off.  But if you look even more closely, you’ll see that each animal has unique markings on their upper and undersides. We passed on our photographs and video for research but, even though they are easy to tell apart, so little is known about them.
  • They are intelligent and coordinate their movements. This is what I found the most fascinating of all, how they knew to all get into a line at the same time and as each of them came by, they were observing me.  They pivoted their eyes back to get the longest look possible at the strange creature who couldn’t stop from screaming out in sheer amazement.