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Posts from the ‘FISH – NE Pacific Ocean’ category

Sharks Among Us #4 – The Salmon Shark

This is a Salmon Shark (Lamna ditropis) that washed up dead on a beach in Carrot Park in Port Hardy, B.C. on November 23rd, 2011. 

Salmon Shark found dead on Port Hardy beach on November 23, 2011. Photo: Mandy Ludlow.

Local Department of Fisheries and Oceans staff conducted an external examination and collected the unfortunate shark so that a full necropsy could be done at a later date.  Although salmon sharks are common in the North Pacific, examining the body may allow science to find out more about the species and how this individual died. 

The dead Salmon Shark was just over 1.5 metres (length from the nose to fork in the tail = fork length). The species can be 3.7 m and weigh up to 454 kg.

Cut in the pectoral fin suggesting the shark died as a result of by-catch in the longline fishery. Photo: Mandy Ludlow.

Salmon Sharks are of no threat to humans, however, the species does suffer impacts from humanity. 

The Port Hardy Salmon Shark had external injuries that suggest it may have been caught in a fishing net and possibly even shot.  It had a large cut on its tongue and on one of its pectoral fins and there was a circular hole behind the dorsal fin.  Many shark species suffer the threat of  by-catch in nets since they are targeting the same species we humans are fishing for.  

If it is determined that this shark indeed was caught in a net, this may be particularly interesting since I believe there are no openings for net fisheries at this time of year. 

Cut also found on the shark’s tongue. Photo: Mandy Ludlow.

Although Salmon Sharks feed on many species of fish, they are indeed a very successful predator of salmon.

Salmon Sharks can regulate their body temperatures to be higher than the temperature of the surrounding water. The Salmon Shark, in fact, has a higher body temperature than any other shark species. Apparently, even when the water is 2° C, their internal temperature can be 16° C.

This ability to thermoregulate is why, in part, Salmon Sharks can be incredibly fast. The US Navy has recorded speeds of up to 80 km/hr.  

I was heartened by the response of the majority of people to the death of this shark. It seems society might be moving beyond the “Jaws Effect” where we demonized sharks because we have bought into their fictitious portrayal.  

Many of us now seem to embrace shark fact rather than fiction, realizing that sharks pose little threat to humans; that they have been shaped by some 200 million years of evolution; that globally they are struggling to survive; and that they have an essential role in marine ecosystems.

Hole behind the dorsal fin. Photo: Mandy Ludlow.

Sharks, as top-level predators, strongly shape food webs.   Loss of such predators has proven to have profound effects on the number and diversity of other species.   

The unenlightened are still out there though. It may be an inevitability that sharks get caught in fishing nets but they need not then be shot or butchered. Locally, I have seen evidence of both. 

[Update: December 22nd, 2011 – The necropsy revealed that this was a female shark. It is also now known that the shark was caught in a hook and line sable fish fishery and that the hole behind the dorsal was the result of a hook. It is rare that there is shark bycatch in this type of non-net fishery.]

Skin parasite (ectoparasite). I have no expertise here but had suggested that this a copepod from the Caligidae family.

For further information on Salmon Sharks, please refer to the natural history information from ARKive below.  

Salmon shark image from ARKive site. Click image for two ARKive videos of salmon sharks hunting. Credit: BBC Natural History Unit.

Salmon Shark Information
from ARKive

Description

A formidable hunter, the salmon shark (Lamna ditropis) is sometimes mistaken for the white shark (Carcharodon carcharias), but can be distinguished by its shorter snout and the dusky blotches that mark the white abdomen of adults (3) (4). The rest of the salmon shark’s stocky, spindle-shaped body is dark bluish-grey or blackish, with white blotches around the base of the pectoral fins. The first dorsal fin is large, while the second dorsal and anal fins are tiny and are able to pivot. Its crescent-shaped tail gives it impressive propulsion through the water (2) (3), while its large, well-developed eyes enable it to spot potential prey (2), and its large, blade-like teeth are well suited to gripping slippery fish(2) (3).

Range

The salmon shark occurs in the North Pacific Ocean. From Japan, North Korea, South Korea and the Pacific coast of Russia, its distribution extends east to the Pacific coast of the U.S.A., Canada, and probably Mexico (3).  See this species on Google Earth.

Habitat

The salmon shark is a coastal and oceanic shark, inhabiting waters between 2.5 and 24 degrees Celsius, generally from the surface down to depths around 152 metres, although one individual has been recorded at 255 metres (3).

Biology

Occurring singly or in schools of several individuals (3), salmon sharks are long distance, high-speed predators (2), occasionally seen at or near the surface in some areas. They can maintain their body temperature well above that of the surrounding cold water of the North Pacific, and may have the highest body temperature of any shark (3). This allows them to maintain warm swimming muscles and internal organs, so they can still hunt effectively in cool waters (2).

The salmon shark is considered to be one of the main predators of the Pacific salmon, and its voracious feeding on this fish has earned it its common name (3). However, it is an opportunistic feeder that consumes a wide variety of fish that also includes (amongst many others) herring, sardines, pollock, Alaska cod, lanternfishes and mackerel. It also feeds on some squid and is sometimes attracted to by-catch dumped back into the ocean by shrimp trawlers (3).

After spending the summer in the north of their range, the salmon shark migrates south to breed. In the western North Pacific they migrate to Japanese waters whereas in the eastern North Pacific, the salmon shark breeds off the coast of Oregon and California, USA. The young are born in spring after a gestation period of around nine months (3). The salmon shark is ovoviviparous (young hatch inside the female; they are nourished by their yolk sac and then ‘born’ live), and oophagy (when the growing embryos eat unfertilized eggs to gain nutrients) has been recorded in this shark (4). Most litters contain between two and five young. Male salmon sharks are thought to mature at about five years and live to at least 27 years; females reach maturity at eight to ten years and are known to live to at least 20 years (3).

Threats

The salmon shark is often caught as by-catch in Japanese, United States and Canadian fisheries. When caught, often just the fins are taken for shark fin soup and the rest is discarded, although sometimes the flesh may be sold for consumption in Japan and the United States (4). Many fishermen view salmon sharks as pests, as they often damage fishing gear, making them more likely to be killed if captured (4). In addition to the threat of by-catch, some recreational fishing for this shark occurs in Alaskan and Canadian waters (4), and some commercial fishing has taken place in the past, such as in Prince William Sound, Alaska (5).

Conservation

In 1997, the Alaska Board of Fisheries closed all commercial shark fishing in state waters and implemented strict regulations in the state sports fishery for salmon sharks (4). Measures such as these are vital in protecting this species’ future, until further research can determine the conservation status of this magnificent predator.

Additional information:

Click here for two ARKIve videos showing Salmon Sharks hunting.

Click here for the petition to ban shark fin products in Canada and here for video by astounding 18-year-old Madison Stewart about the vilification of sharks and the atrocities of shark-finning . . . 73 million sharks killed/year for their fins = 190 sharks killed/minute.

Holy Mola!

Update February 2nd, 2021
This blog was written in 2011 reporting this to be a Mola mola.
I can now share that this is NOT a Mola mola. It is a Mola tecta! It is now known that there are two species of Mola in the NE Pacific Ocean. See the CBC news article announcing this here: Meet the Hoodwinker, the Ocean Sunfish we Misidentified for Years.

Mola tecta is the Hoodwinker Sunfish. See diagram at the end of this blog for the discerning characteristics.

As a result of writing this blog in 2011 (with the great photos taken by friends), I was contacted in 2020 by the researcher who could discern this species, Marianne Nyegaard who works in New Zealand. Now, in my role with the Marine Education and Research Society, we are helping get more sightings of Mola off the coast of BC to get a better sense of relative abundance. To relay sightings, please see this link.

Something very unexpected landed near the Port Hardy seaplane base on October 20th, 2011 – a dead Mola tecta. This species of ocean sunfish looks like a cartoon character rather than a relatively fast-moving, deep-diving fish whose design has been perfected by millions of years of evolution.

Chad Chrighton, the pilot who found the Mola tecta near the seaplane base. Photo credit: Mike D’Amour (North Island Gazette).

This fish species is aptly named since Mola means “millstone” in Latin and indeed this fish looks like a huge, flat, gray circle and has rough skin.  It appears to have no body, only a giant, round, flat head with a small beak-like mouth. It is propelled by two pointy fins (dorsal and anal) and is steered by a wide, rounded, rudder-like tail. 

Photo credit: Erika Grebeldinger.

Mola species were believed to be passive drifters who travelled only at the surface, wherever the current took them. However, satellite tracking studies have revealed that they dive deeper than 600 m and travel an average of 10 to 20 km per day, the same distance traveled by open-ocean shark species. 

 

Matthew Drake measuring the Mola tecta To give you get a sense of size, Matthew is 2m tall (6.5′). Photo credit: Erika Grebeldinger.

They are certainly a rarity on the inside of Vancouver Island however and I greatly appreciate that Matthew Drake let me know about this find and that he undertook a necropsy of the giant together with Louisa Clarke and Natasha Dickinson. 

This Mola tecta measured 2.00 m wide, from beak to tail fin, and 2.06 m long, from the tip of one pointy fin to the other. It may have weighed more than 200 kg. Remarkably, this is small for its kind. Mola tecta hold the record for being the largest bony fish on earth with an average mass of 1 tonne. The largest Mola mola (cousin to Mola tecta) ever recorded was 2,235 kg and 3.10 m by 4.26 m (it was struck by a boat near Australia in the early 1900s). Note that the whale shark can be more than 9 times bigger than this but, it is not a bony fish. 

Mouthparts. Photo credit: Mandy Ludlow.

Matt and the team concluded that the Port Hardy Mola tecta was female which meant that she could have up to 300 million eggs in her one ovary. This is another record for the species: having more eggs than any other animal with a backbone.  Another astounding fact is that the larvae could grow to be 60 million times their weight at hatching.

The investigation also revealed partially digested jellyfish in her gut, which is the typical prey of Molas / Sunfish. Their diet also includes small fish, eelgrass and crustaceans and they are able to spit out and pull in water and food with their unique mouthparts. As with all species that feed on jellies, a conservation concern is that they mistake plastic bags for their food. However, there was no evidence for this being the cause of death for this particular Mola tecta.  

Maybe parasites were a factor in her death? The team found lots of skin and intestinal parasites! Some of the round worms in the guts were even still alive. Parasites are common for Mola molas. In fact, it is now believed that the behaviour of “sunning” at the surface (hence, ocean “sunfish”) might be so that birds can feed on the skin parasites and that jumping more than 3 m out of the water might help dislodge some parasites too. Mola tectas are also found associated with drifting kelp patches, where small fish can clean away the pests.  

HOLY MOLA you never know what you are going to find in our amazing marine backyard. 

All the information collected was reported to oceansunfish.org and the mouth parts are on display in Telegraph Cove’s Whale Interpretive Centre. 

 

Beware!  Fabulous Mola tecta parasite pictures below! 

Advance only if you are NOT about to eat lunch and/or if you a biology-type like me who can view these kinds of photos in rapturous fascination anytime!

Photo by Erika Grebeldinger.

Sources: 

Links regarding other Mola species:

 

 

Her intestines were an astounding mass of worms. Likely the species include the parasitic flatworm, Nematobibothrioides histoidii which is thread-like but can grow to be over 12 m (40′). No one apparently knows just how long they can become, in part because dissections/necropsies on Mola mola are rare events. Photo credit: Natasha Dickinson. 

Parasites near the eye. Photo credit: Mandy Ludlow.

More great ectoparasites. Photo credit: Matthew Drake. 

Her single ovary. Can have 300 million eggs. Photo credit: Natasha Dickinson. 

 

Sharks Among Us #3 – Meet the gang – From Rat Fish to Sixgills! (Video)

Great thanks to Rendezvous Dive Adventures for sharing this video with me! 

It’s a fantastic (7.5 minute) interview with Dr. Chris Harvey-Clark of the University of British Columbia and the Greenland Shark and Elasmobranch Education and Research Group (GEERG).

He discusses the shark species found in our cold-rich waters in the Pacific Northwest: “We have some of the largest species of sharks in the world swimming in these waters”.

Great video of sharks and I particularly appreciated Dr. Harvey-Clark’s explanation of the ecological link between rat fish and bluntnose sixgill sharks and, related to this, the latest research on the “ocean wanderings” of sixgills. 

I learned too about the Shark Observation Network where divers’ observations can help research. 

Basking in History – The Reality of B.C.’s Basking Sharks

Last updated: March 4, 2026
If you ever see a Basking Shark in British Columbia: call 1-877-50-SHARK (1-877-507-4275), or email sharks@dfo-mpo.gc.ca, or fill in the reporting form at this link. Please see info below about how to identify a Basking Shark.  

Photo by Chris Gotschalk
(Wikimedia Commons)

It’s a first. Canada has now (2011) acknowledged the endangerment of a marine fish species – the Basking Shark (Cetorhinus maxiumus). 

Basking Sharks used to be common in the coastal waters of British Columbia.  As the second largest fish species in the world, they could be half the size of a city bus (12 m and 4 tonnes) and could be seen at the surface of the ocean, “basking” there to feed on plankton. It’s a long-lived species too, believed to be able to reach 50 years of age.

However, even the most seafaring fisher is now unlikely to ever see one off the B.C. coast. There have been less than 25 sightings of Basking Sharks since 1996. So what happened?

We slaughtered them.

These sharks were put on the Canadian fisheries “Destructive Pests” list in 1949, and from 1955 to 1969 there was a federal eradication program directed at these benign, plankton-eating giants. In these years, the federal fisheries patrol vessel, the Comox Post, even had a blade mounted on its bow, designed specifically to slice Basking Sharks in half.

This species of shark has only the tiniest of teeth and does not compete for a commercial fishery like the sea lions, seals and Killer Whales that were also culled in that time period. The motivation for the “pest control” of these gentle giants was that they got trapped in gill nets, causing damage to fishing gear.

Who we used to be. Blade on the front of the Comox Post. Source: Popular Mechanics 1956.

As an indicator of how far we have come since then, imagine the social outrage today if a magazine celebrated the ingenuity of the Comox Post’s blade, illustrating how the executioner’s tool was used accompanied by the text “Huge 30-foot basking shark is almost cut in two by sharp-edged ram. The sharks, floating lazily near the surface of the water, are no match for this skillfully handled vessel, which heads directly into a school and catches an individual shark before it is aware of its plight”.  November 1956’s edition of Popular Mechanics featured just that and the June 22,1955 front page of the Victoria Times included a photo with the text “This is a basking shark, basking and leering. But the smirk will soon be wiped off its ugly face by the fisheries department, which is cutting numerous sharks down to size” (from The Slaughter of B.C.’s Gentle Giants by Scott Wallace and Brian Gisborne).

Further: “After the initial flurry of press commentary on the shark blade in 1955 and 1956, the Comox Post went about its daily job, firing bullets into the occasional sea lion, seal, or merganser and slicing sharks when seasonally abundant. At the end of each fishing season an annual report was written, and over the years the entries for basking sharks appear to diminish. The blade was used over a period of 14 years in the Barkley Sound region, during which time 413 kills were recorded.” In 1956 alone, 105 Basking Sharks were reported to have been killed.”

Basking Sharks survived as a species for at least 30 million years but have been pushed to the brink extinction in B.C. by just a couple of decades of human intolerance, misunderstanding and mismanagement.

But as a testament to how quickly human social evolution can occur, we have gone from being executioners to acknowledging the species’ endangerment in just over 40 years.  In February 2010, the Pacific population received legal protection by being listed as “endangered” under Canada’s Species at Risk Act. The Recovery Strategy was finalized at the end of July, 2011. 

Only history will tell if our evolved enlightenment is enough or if it came too late for the Basking Shark and many other marine species. The fact that you care enough to read this blog item is every reason for hope.

Above: Basking Shark sighting July 17, 2024 near East Sooke by Island Magic Experiences.

Above: Basking Shark sighting July 17,2017 in Caamano Sound, BC. Video by Archie Dundas of the GitGa’at Guardians via Fisheries and Oceans Canada.

Presentation about Basking Sharks by yours truly and Romney McPhie of Fisheries and Oceans Canada for Ocean Day 2022.

Click here for this annotated Basking Shark colouring sheet by Romney McPhie who is not only a shark scientist but clearly also an artist (and very skilled educator)!

Sources:

Fisheries and Oceans Canada. 2011. Recovery Strategy for the Basking Shark (Cetorhinus maximus) in Canadian Pacific Waters [Final]. Species at Risk Act Recovery Strategy Series. Fisheries and Oceans Canada, Ottawa. v + 25 pp.

Fisheries and Oceans Canada. 2019. Action Plan for the Basking Shark (Cetorhinus maximus) in Canadian Pacific waters [Proposed]. Species at Risk Act Action Plan Series. Fisheries and Oceans Canada, Ottawa. iii + 16 pp.

Species at Risk Act (SARA) Species Profile 

The Tyee, December 7, 2016, How BC Killed All the Sharks – Hysteria and a knifelik ram helped us slaughter the benign basking giants by Scott Wallace and Brian Gisborne

Wallace, Scott, and Brian Gisborne. 2006. Basking sharks: the slaughter of BC’s gentle giants. Vancouver: New Star Books.

Western Washington University. 2026. Recording of webinar Basking Sharks in the Salish Sea (see below)


Basking distribution.001

In the Eye of the Lord (the Red Irish Lord that is!)

The Red Irish Lord (Hemilepidotus hemilepidotus; up to 51 cm) is a fish of incredibly stunning diversity of colour. Right down to its flecked, bulging eyes, this ambush predator is a master of camouflage. 

But how can you be camouflaged when you’re a fish of insane red and/or orange colouring? When you live in the rich, cold waters of the Northeast Pacific where Nature has doled out colour so liberally, you fade into the background even when so vibrantly coloured.  

They are a favourite species for we underwater photographers since, as ambush hunters, they remain still even when annoying divers are flashing lights in their eyes or when a crab is sitting on their heads (see below).

The diversity of colour in this species is awe-inspiring. See below for examples of the diversity of colour and pattern and their ability to camouflage. You will even see that there are crabs that walk on their heads. I have a whole blog entitled “Crabs Making Bad Choices” dedicated to that at this link.

I hope that your sense of wonder is further stimulated in realizing that the Red Irish Lords are able to change even the colour of the flecks in their eyes to match their surroundings! 

The remarkable eyes of the Red Irish Lord. The flecks you see are corneal chromatophores which can change colour to add the to species’ ability to camouflage.

See too how Red Irish Lords are among the fish who guard their fertilized eggs.

Both male and female Red Irish Lords guard the eggs. More information in my blog at this link.

A Red Irish Lord who is hoping the Sharpnose Crab inches down just a bit further so that s/he can feed (and that the annoying photographer would go away!). See my blog “Crabs Making Bad Choices” for more photos of such interactions at this link.
Another Red Irish Lord and a mature male Sharpnose Crab making bad choices.

Slide show and gallery of photos below give a further sense of the diversity of colour and camouflage in this species. 

Guarding fertilized eggs.

Lingcod – Fastidious, Fanged Fathers!

Last update: March 21, 2024.

Update November 2021: New research finds Lingcod replace ~2 of their 500 teeth every day.

Every year, our local dive club does several dives for the Lingcod Egg Mass Survey now curated by the Marine Life Sanctuaries Society.

Lingcod male guarding eggs
Lingcod male guarding an egg mass. Generally, the larger the egg mass, the older the female that laid it. Males guard the fertilized eggs from predation by other fish and sea stars until they hatch at 5 to 11 weeks. Photo: ©Jackie Hildering.

The survey is the result of concerns about the overfishing of this fish species and is conducted just after the spawn (January to February) when females leave the males to guard the egg masses from predation by species like sea stars. There are very few deadbeat dads in this species!

The data collected provide insight into the abundance and reproductive success of Lingcod in British Columbia and include: depth of the egg masses; their size (grapefruit, cantaloupe or watermelon sized); if the eggs are being guarded by a male; and their state of development (new, eyed or rotten). We are very fortunate that our area appears to have relatively abundant and large egg masses. At the end of this blog, you’ll find my 2.5 minute slide show of their life history. 

Male Lingcod with my buddy with her slate, having just recorded depth, size and condition of the egg mass. Buddy is Natasha Dickinson. ©Jackie Hildering.

But let me first take you on a wee retrospective journey.  

My understanding of the behaviour of these magnificent fish has now evolved  to where I now take photos of the extremely territorial males guarding their large orbs of fertilized eggs, but it certainly wasn’t always that way for me. The following is a much exaggerated perspective from when I was a very new diver doing their first Lingcod egg mass survey.

In 1999, I had only ever done 14 dives and had never even seen a Lingcod while diving. So, in preparation for the survey, I consulted my trusty field guide and felt well-prepared knowing the information below:

Lingcod male guarding egg mass (lower right). ©2015 Jackie Hildering
Lingcod male guarding egg mass (lower right). ©Jackie Hildering.

LINGCOD (Ophiodon elongatus)

  • Size: To 1.5 m and 37 kg.
  • Description: Large head, mouth and teeth; dark blotches on a slender, tapering, mottled body.
  • Habitat: Adults on rocky reefs and in kelp beds to 2,000 m; juveniles on sand and mud bottom.

However, nothing could have truly prepared me for meeting the awe-inspiring and highly dedicated Lingcod Fathers for Future Generations Club.

Serious teeth. ©2012 Jackie Hildering.
Serious teeth. ©Jackie Hildering.

That first experience with the survey in 1999 led me to writing the following tongue-in-cheek “updated” field guide information in my dive log.

LINGCOD (Megadontos fishious)

Size: &%$#@ huge!!!!!

Description: Teeth sharp, large and fear inducing; species camouflaged for added surprise value; ability to make themselves appear even larger and more menacing by fanning out huge gill plates (opercula). Note: Wise for divers to retreat if this behaviour is observed.

Habitat: Adult males found anywhere that groups of dive slate carrying divers like to congregate.

Comment: Egg masses are said to have eyes at some stage of their development but no living diver can confirm that this is the case!

This is an awe-inspiring fish species indeed. I have even had a male knock my dive slate out of my hands during a survey. Ironically, I was recording “absent” under the column for whether a male was guarding the egg mass!

Huge egg mass and male Lingcod with battle wounds. It is so meaningful to me that we are likely often documenting the same males year upon year. The males apparently court, mate and guard near the same rocks every year.  ©Jackie Hildering.
Huge female Lingcod. After age ~4, females grow twice as fast as males. By age 10 to 12, they are twice the size of males of the same age. Bigger females lay larger egg masses – up to 500,000 eggs! More on the life history in my slide show below. ©Jackie Hildering.

Note that the common name of Lingcod is confusing as they are not a cod nor a ling (another fish species).

For detailed information on the survey, survey reports and the biology of Lingcod click here for the Ocean Wise webpage. 

Okay, maybe not looking so serious here. :) ©2012 Jackie Hildering.
Okay, maybe not looking so serious here. ☺️
©Jackie Hildering.
Guarding egg mass. ©Jackie Hildering.
So much to protect. ©Jackie Hildering.

Sources:
Alaska Department of Fish and Game, Lingcod

Lamb, A., & Edgell, P. (2010). Coastal fishes of the Pacific Northwest. Madeira Park, B.C: Harbour Pub.

Love, M. S. (2011). Certainly more than you want to know about the fishes of the Pacific Coast: A postmodern experience. Santa Barbara, Calif: Really Big Press.

Sharks Among Us #2 – The Bluntnose Sixgill Shark

Update May 1, 2023: Original blog is from 2011. I have added photos of additional, known dead Sixgill Sharks at the end of this blog.

And yes, there is a personal connection to this species. While these huge sharks are often in very deep water, I have seen them while diving in at depths of even less than 10 metres. It’s difficult to express the wonder and connection that results from these privileged experiences. It’s somewhat like seeing a living dinosaur. Bluntnose Sixgill Sharks have been perfected by 200 million years of adaptation.

They are not a threat to us. We are a threat to them.

The awe-inspiring images below are of a pregnant female Bluntnose Sixgill Shark (Hexanchu griseus) who 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 below has been generously provided by shark biologist and friend, Romney McPhie. I am sharing in the hopes of increasing respect and understanding for these astounding, huge, deep-dwelling sharks who live off our coast.

4.2 m pregnant female Sixgill Shark – February 2011.

This female Sixgill was 4.2 metres and was estimated to weigh 569 kg (1,254 lbs).  As a viviparous shark species, she carried her embryos through the entire gestation period which is thought to be over 2 years long (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. The young hatch inside the female’s body before entering the ocean (these sharks are “yolk-sac viviparous”).

Sixgill Sharks have been reported to be up to 4.8 metres in length with females being larger than males (males to 3.5 metres). Age of 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 were 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 Bluntnose Sixgill Sharks 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.

There were historical fisheries and bycatch remains a concern. From 2006 to 2009 there an estimated 1979 Bluntnose Sixgill Sharks were Commercial Hook and Line catch

There is no information on the survival rates from bycatch nor of the accuracy of bycatch reporting. Population size and reproductive rate are not known for this species.

“The primary threats identified for these species are entanglement and bycatch.  Other threats identified include pollution, habitat loss or degradation, climate and oceanographic change, and harassment. Historic threats included directed fisheries and entanglement/bycatch. While these populations are migratory throughout the northeast Pacific, it is unknown whether threats occurring outside of Canadian Pacific waters have an impact on these populations.”

Further from the 2022 Fisheries and Oceans Canada Report on the Progress of the Management Plan for Bluntnose Sixgill Sharks:

“The present population size and abundance trends are not known. The only available abundance index (encounter rates with immature Bluntnose Sixgill Sharks at a shallow site in the Strait of Georgia) has decreased significantly (>90%) in the last five years. This index is not likely representative of the overall abundance trend because only immature Bluntnose Sixgill Sharks are encountered and the site is shallow relative to the preferred depth range. The principal known threat to the species is fishing.

The Bluntnose Sixgill Shark has been the focus of at least three directed fisheries in Canadian waters, most recently in the late 1980s and early 1990s. It continues to be caught as bycatch, but survival of released sharks is unknown. Bluntnose Sixgill Sharks observed by divers sometimes show scars from entanglement in fishing gear.

Because of its late age of maturity (18 to 35 years for females), it is likely susceptible to overfishing even at low levels of mortality. Little is known about the abundance and movement patterns of this species elsewhere in the world, so the potential for a rescue effect is unknown.“

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.

Sources for the biology, threats and conservation of Bluntnose Sixgill Sharks:

Fisheries and Oceans Canada. 2022. Report on the Progress of Management Plan Implementation for the Bluntnose Sixgill Shark (Hexanchus griseus) and Tope Shark (Galeorhinus galeus) in Canada for the Period 2012 to 2017. Species at Risk Act Management Plan Report Series. Fisheries and Oceans Canada, Ottawa. iv + 20pp

Fisheries and Oceans Canada, 2012. Management Plan for the Bluntnose Sixgill Shark (Hexanchus griseus) and Tope Shark (Galeorhinus galeus) in Canada [Final]. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Ottawa. iv + 37 pp.

COSEWIC (Committee on the Status of Endangered Wildlife in Canada). 2007a. COSEWIC assessment and status report on the Bluntnose Sixgill Shark (Hexanchus griseus) in Canada. COSEWIC, Ottawa, Canada.

NOAA, 2017. Getting to know Sixgill Sharks.

Photo #1 April 2023 – Dead pregnant Bluntnose Six-gill Shark, Hornby Island.
Photo #2 April 2023 – Dead pregnant Bluntnose Six-gill Shark, Hornby Island.
From the Vashon Nature Center: in Puget Sound – 4 Bluntnose Sixgill Sharks washed between January and March 2023. Two could not be necropsied. One died after longline bycatch and one died by swallowing a crab bait trap Blog article about the first necropsy at this link.
Photo #1 Coles Bay, February 5th, 2019: Dead pregnant Bluntnose Sixgill Shark
©Ron DeVries.
Photo #2 Coles Bay, February 5th, 2019: Dead pregnant Bluntnose Sixgill Shark
©Ron DeVries.

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”.