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’ category

Sharks Among Us – The Brown Cat Shark

Here’s a mystery shared (and solved) by Farlyn Campbell.

This was found in May of 2018 north of Port Hardy.

Photo: Jared Towers. Brown Cat Shark egg case found on May 30, 2018 near Doyle Island off NE Vancouver Island, British Columbia. Found by Jared and Farlyn when they came upon a rope with buoy drifting in the ocean. They removed the rope due to its potential to entangle animals and of course placed the egg case back in the ocean. 

It’s the egg case of a Brown Cat Shark (Apristurus brunneus) with an embryo developing inside and it’s mind-blowing how long it takes before it hatches. Read on!

The Brown Cat Shark is a common species of shark off British Columbia’s coast but, here we go again . . . very little is known about it.

Most sharks (about 60%) have “viviparous” reproduction where the young develop inside the female and hatch out when fully developed.

However, Brown Cat Sharks have “oviparous” reproduction where the eggs hatch outside the body of the female. The embryo develops inside the egg, feeding on the yolk. Yes, this is how birds develop too. The egg cases of oviparous sharks are not shelled however, as you can see above. They have distinct shapes per species but all have this tough “leathery” membrane. The egg cases are also known as a “mermaid’s purses”. (See the end of this blog for further information on reproductive strategies in sharks).

Female Brown Cat Sharks lay one egg case at a time that contains a single embryo. Each egg case is around 5 cm long and 2.5 cm wide. In the case of Brown Cat Sharks, the embryo develops inside for more than 2 years! In our cold waters, maximum known incubation period is 27 months. The size of the hatched pup is 7 to 9 cm. (Source: Love). Development is shorter where temperature is warmer.

The distinctive “tendrils” on the egg cases of Brown Cat Sharks are believed to help anchor them to hard surfaces.

In British Columbia, the females carry (and deposit) between 1 to 16 mature eggs most often between February and August. (Source: Love and McFarlane). Further to the south in their range, they females apparently lay egg cases year round.

Little is known about what feeds on the egg cases but bore holes suggest that gastropods like whelks drill into them.

Brown Cat Shark – Details 

See below for more information on the 16 species of shark known to be off the coast of BC. Image source:  Fisheries and Oceans Canada, Sharks of British Columbia. 

Cat sharks (Scyliorhinidae) are the most diverse and largest family of living sharks. There are ~157 species worldwide. Their common name may be in reference to their cat-like eyes.

Brown Cat Sharks are harmless to humans. They feed on small true shrimps, pelagic red crabs, euphausiids, mysid shrimps, isopods, squids, and small fishes (Source: Love) Off the coast of BC, maximum documented size for the Brown Cat Shark is 70.4 cm for males and 65.1 cm for females (Source: Wallace et al).

The Brown Cat Shark is a cold water species, found in waters from 5 to 8°C in the Eastern Pacific. They appear to be most common from British Columbia to northern Baja California, Mexico with their known range extending from Alaska to Columbia in South America. They are probably also off Panama, Ecuador, and Peru.

Known global range of the Brown Cat Shark. Source: IUCN. 

 

Brown Cat Sharks are a deep-dwelling species, often over mud/sand and on the outer continental shelf. Known depth range is 33 to 1,298 m. They are most often found at depths of 137 to 360 m in the cold waters off the coast of British Columbia. Where it is warmer, they are likely to be deeper e.g. most often at depths of 656 – 932 m off southern California (Source: IUCN).

Distribution of Brown Cat Shark off the west coast of Canada from 1965 to 2007. Source: McFarlane.

As aforementioned, the Brown Cat Shark is one of the most common shark species off the coast of BC but so little is known about it and there have not been the recommended efforts to fill knowledge gaps.

Risks to the Brown Cat Shark include that it is commonly taken as bycatch in deepwater trawl fisheries (Source: IUCN). The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) reported in April 2007 that there was not enough information known about the species to evaluate how at risk it was =  Data Deficient. MarFarlane et al, 2010 determined that the Brown Cat Shark was among those shark species off the coast of BC that was a high priority for further study.  This has not yet happened. Reportedly, there are no management measures currently in place for the Brown Cat Shark anywhere in the world (Source: IUCN).

Shark Reproduction 

Unlike most fish, sharks have internal fertilization, where the eggs are fertilized inside the female’s body. The males have reproductive structures known as “claspers” (modified parts of the pelvic fins). Claspers are appropriately named as, not only do they transport sperm into the female’s oviduct, they also anchor into the female.

Most sharks are viviparous, giving birth to fully developed young. As mentioned above, Brown Cat Sharks are not. They are oviparous.

Shark egg development modes in further detail:

Oviparity = egg-laying. After fertilization, the egg cases are deposited into the ocean. There is no development of the embryo inside the female. The embryo develops inside the egg case feeding on the yolk. The only oviparous shark off the coast of BC is the Brown Cat Shark. The skates off our coast are oviparous as is the Spotted Ratfish. (See the image at the end of this blog contrasting their egg cases / mermaid’s purses).

Viviparity = after fertilization, the embryo develops inside the mother and the young are fully developed when born. There are two types of viviparity:

  1. Placental viviparity:
    We humans and most other mammals and reptiles also developed via placental viviparity. The embryos develop inside the mother, attached to her placenta (in the case of viviparous sharks, the umbilical cord is between the pectoral fins). Through the placenta, the mother’s blood delivers nutrients and oxygen to the embryo and waste is transported away. Examples of sharks off the coast of BC who develop by placental viviparity: Sixgill Shark, Sevengill Shark, Blue Shark, Pacific Sleeper Shark, Spiny dogfish.
  2. Aplacental viviparity (Ovoviviparity): In this case, there is no placenta to nourish the embryo. The young develop inside the eggs while in the mother’s oviduct and are born fully developed. They feed from the yolk as well as from glands in the oviduct walls (there are varied ways this “uterine milk” is delivered). The embryos hatch into the oviduct and finish development feeding from gland secretions and unfertilized eggs (known as being “oviphagous”). In some species, the first pup to hatch eats their developing siblings. This is referenced as being “embryophagic” or “adelphophagic” (translates literally into “eating one’s brother”) and is not known in any other animals other than some species of sharks. You can imagine that final litter size is small in sharks with this “intrauterine cannibalism”. Examples of sharks off the coast of BC who develop by aplacental viviparity are: Tope (Soupfin) Shark, Pacific Angel Shark, Spiny Dogfish, Common Thresher Shark, Bigeye Thresher Shark, Shortfin Mako Shark, Basking Shark and Salmon Shark. Those whose embryo development is known to include embryophagy are the: Common Thresher Shark, Bigeye Thresher Shark, Shortfin Mako Shark, Basking Shark and Salmon Shark (Source: Elasmo-Research).


Sharks off the Coast of British Columbia

Image source:  Fisheries and Oceans Canada, Sharks of British Columbia. Click to enlarge.

In BC waters there are 16 species of shark from 11 families.

Brown Cat Shark (Apristurus brunneus)
Spiny Dogfish (Squalus acanthias)
Sevengill Shark (Notorynchus cepedianus)
Salmon Shark (Lamna ditropis)
Blue Shark (Prionace glauca)
Pacific Sleeper Shark (Somniosus pacificus)
Common Thresher Shark (Alopias vulpinus)
Bigeye Thresher Shark (Alopias superciliosus)
Shortfin Mako Shark (Isurus oxyrinchus)
Green-Eye Shark (Etmopterus villosus)

Protected under Canada’s Species at Risk Act:
Basking Shark (Cetorhinus maximus) – Endangered
Sixgill Shark (Hexanchus griseus) – of Special Concern 
Tope (or Soupfin) Shark (Galeorhinus galeus) – of Special Concern

Incidental:
Great White Shark (Carcharodon carcharias)
Hammerhead Shark – 2 known sightings up to 2016 (Source: Royal BC Museum)
Pacific Angel Shark  – 1 known sighting up to 2016 (Squatina californica)

Contrast of egg cases commonly found along coastal British Columbia. Only the Big Skate can have more than one embryo per egg case. Reported to be up to a maximum of 7 embryos but more often 3 to 4.

Sources:

 

Find the Fish – The Book!

It’s a monumental day in my world and many of you here have provided the sense of community and support that have made the following a reality.

My first book can now be ordered.

My  . . . first  . . . book!

Find the Fish cover. Book is softcover 8.5″ wide x 11″ high (21.5 cm x 28 cm) with saddle-stitch binding (two staples).  

It’s “Find the Fish” – an eye-spy style book. It’s the “Where’s Waldo” of the marine world aimed at increasing awareness of the life in the NE Pacific Ocean.

In addition to being fun, the book is intended to add to the knowledge of just how diverse and colourful life is in these cold, dark waters. Text provides background on the images and invites children to look for other species as well as the featured fish.

It is soft-cover and features eleven searches for fish. Each search is spread across two pages to be 17″ by 11″ (43 cm x 28 cm). Answer pages are included showing the location of the fish with additional labeling of other species. Please see example pages below.

Example 1 of the Find the Fish challenges in the book. ©2017 Jackie Hildering.

Example 2 of the Find the Fish challenges in the book. ©2017 Jackie Hildering.

Example 3 of the Find the Fish challenges in the book. ©2017 Jackie Hildering.

Two of the four answer pages providing the location of the fish and labelling of additional species. ©2017 Jackie Hildering.

All photos and text are by yours truly with illustrations of the featured fish generously provided by Andy Lamb of Coastal Fishes of the Pacific Northwest. Fish ID help was also provided by Gregory Jensen of Mola Marine.

Find the Fish is aimed at children ages 5 to 10 and the adults who love them!

The books are $18 each (tax included). YOU CAN ORDER BY CLICKING HERE 🙂 . 

Again, thank you for YOUR role in making this a reality.

Details:

  • Shipping in Canada $3/book; USA $6/book; international airmail $10/book.
  • No shipping charge if picking up in Port McNeill. Please contact me by clicking this link before placing a local order.
  • Softcover 8.5″ wide x 11″ high (21.5 cm x 28 cm).
  • Saddle stitched binding (two staples).
  • Cover + 32 colour pages which include:
    • Introduction to the fish and the importance of camouflage.
    • 11 Find the Fish challenges spread across two pages.
    • 4 answer pages.
  • Self-published as Marine Matters Publishing. 

Product testing! 🙂

Ra Ra Ratfish!

LOOK at this fish!

Those who are as in awe of the species as I am, describe it as “adorably bizarre” (Dr. Milton Love) and as “true survivors from before the dinosaurs . . . no wonder they look like they’re from another world.” (Ray Troll, source 5).

Spotted Ratfish. ©2016 Jackie Hildering

Spotted Ratfish (Hydrolagus colliei). Maximum size 1 m and 1.8 kg; females are larger than males.
©2016 Jackie Hildering

Maybe not as flattering a description, but certainly accurate is: “They look like you put three or four things in a blender” (unnamed scientist, source 5).

Indeed, this family of fishes is aptly named the “Chimeras” for the creature from Greek mythology that is a composite of other species.

Spotted Ratfish (and a Blackeye Goby). ©2016 Jackie Hildering.

Spotted Ratfish (and a Blackeye Goby). ©2016 Jackie Hildering.

The common name of this fish is the “Spotted Ratfish” favouring the perceived likeness to that rodent. The scientific name “Hydrolagus collieli” favours the rabbit-like resemblance with “Hydrolagus” translating into “water rabbit”.

For me, it is an exquisitely beautiful species and a source of marvel. Notice the wing-like pectoral fins; huge eyes that seem to be able to pivot back and forth in their sockets; scaleless, white-spotted skin with a silvery sheen; and the beautiful gold “stitching” that make it look all the more like it has been assembled from other parts.  Oh and then there are the remarkable structures in the males! Read on for an explanation of what they’re all about.

©2016 Jackie Hildering

Male Spotted Ratfish. ©2016 Jackie Hildering.

Likely Spotted Ratfish are well known to many fisher-folk in their range from the western gulf of Alaska to southern Baja California but, as a fish out of water, I think it is so difficult to see the species’ beauty. We divers are so lucky to see them below the surface and I’m hoping the photos and information below enhance an appreciation for this fish that should never, ever be referenced as “ugly”! 🙂

Are they sharks? The Chimeras are closely related to rays, skates and sharks. They are all cartilaginous fishes (Chondrichthyes) but Chimeras are in a different sub-class.

Senses: Like rays, skates and sharks, they have pores in their heads with which they can detect the electrical fields of their prey – even tiny heartbeats under the sand (source 5). Their huge eyes suggest that Spotted Ratfish are more active at night.  Even though Spotted Ratfishes are often in the shallows, my personal observations support that their eyes are designed to function in low light. I will never forget my excitement at seeing one for the first time and, without thinking, turning my dive light on the poor guy. The result appeared to be that I temporarily blinded him. He swam forward – directly into a rock. Eek!

Close up on the head of a Spotted Ratfish. ©2016 Jackie Hildering.

Close up on the head of a Spotted Ratfish. ©2016 Jackie Hildering.

Diet: Ratfish have plate-like grinding teeth and they are reported “to have the highest jaw leverage of any cartilaginous species studied” (source 3). This makes them well-suited to be able to crush the hard bits of fish, crabs including hermit crabs, shrimp, snails, sea urchins, worms, bivalves like clams, and isopods (source 9).

Defences: In addition to their biting strength, Spotted Ratfish have a retractable spine with a venom gland. See it there in front of the dorsal fin? This causes some discomfort in humans but, one study revealed that it can be fatal to Pacific Harbour Seals by perforating the esophagus or stomach and migrating into vital tissues. The spines have also been found in the heads and necks of a few California and Steller Sea Lions but have not been proven to be the cause of death (source 1).  In addition to seals and sea lions; Spotted Ratfishes’ predators include Sablefish; shark species like the Bluntnose Sixgill and Spiny Dogfish; birds like Buffleheads, Common Murres and Pigeon Gullemots; Humboldt Squid and, apparently, Northern Elephant Seals eat their eggs (source 9). We humans only went after Spotted Ratfish for their livers in the 1800s. We don’t like the taste of their flesh – lucky Ratfish.

Spotted Ratfish. See the spine in front of the first dorsal fin? ©2016 Jackie Hildering.

Spotted Ratfish. See the spine in front of the first dorsal fin? ©2016 Jackie Hildering.

Mobility: In having such a thin, whip-like tail that can’t provide much force, propulsion in Ratfish comes from their wing-like pectoral fins. It is such a thing of beauty to see them swim, or is it fly? Like rays, skates and sharks, they have large livers that aid buoyancy whereby they can hover in the water column and then glide off.


Video: Spotted Ratfish swimming. ©Jackie Hildering. 

Female bits: Like many rays, sharks and skates, chimeras are “oviparous”. Fertilization is internal and then egg cases are laid. The leathery egg cases look like “little violin cases” (source 2) and each contain one egg. As seen in Wendy Carey’s remarkable photo below, they female “extrudes’ two egg cases at a time – one from each oviduct. Reportedly, they often hang from her in the water column for four to six days before falling to the ocean bottom. Then, she lays another pair (this suggests female Ratfish may be able to store sperm). The baby Ratfish develop within the egg case for 5 to 10 months and then wiggle out when they are around 14 cm.  It appears to me that they spawn throughout the year but there may be a peak from May into October (source 9). Little is known about the longevity of Ratfish but preliminary research suggests that they are likely late maturing with females becoming sexually mature at age ~14 and males at age ~12 (source 7).

Female Spotted Ratfish egg-laying. ©Wendy Carey.

Female Spotted Ratfish egg-laying. ©Wendy Carey.

Male bits:  So those “dangly bits”, what are they?

The claspers in the pelvic area you may know from shark species. They are the males’ sex organs containing sperm and they are used only one at a time to inseminate the female.

Male reproductive organs. ©2016 Jackie Hildering

Male reproductive organs. ©2016 Jackie Hildering

Male Spotted Ratfish found dead on beach. ©Jacqui Engel.

Male Spotted Ratfish found dead on beach. Frontal tenaculum is being pointed out. ©Jacqui Engel.

The remarkable stalked club structure with little hooks on the male’s head is the “frontal tenaculum” and it is unique to adult males in the Chimera family.  It is usually withdrawn into the groove in their foreheads but, during copulation, is used to clamp onto the female’s pectoral fin. There is also another grasping structure, the pre-pelvic tenaculum, just before the pelvic fins that also allow the male to anchor into position.

In sharks, males bite onto the female’s pelvic fin to get into position but I suggest, with Chimera’s very different teeth, this would not work well and thereby, that there was a selection pressure for such unique structures. It is noteworthy too that male Chimeras have to be much smaller than females because otherwise, with their heads attached onto the pectoral fin, they wouldn’t be able to position a clasper into the female (source 8).

Ray Troll (colourful always) describes the frontal tenaculum as a “girl grabber” but don’t let that suggest that there isn’t courtship between Ratfish. Apparently, there are colour changes and distinct swimming patterns and, once the male’s clasper is inserted in the female, they swim together like this for between 37 and 120 minutes (source 9).

I assure you, if I manage to witness Spotted Ratfish courtship or mating, there WILL be an update to this blog!

©2016 Jackie Hildering

Now you know – mature male or female? ©2016 Jackie Hildering

Male Spotted Ratfish near the surface. ©Jackie Hildering.

Male Spotted Ratfish near the surface. ©Jackie Hildering.

Sources:

  1. Akmajian, A. M., D. M. Lambourn, M. M. Lance, S. Raverty, and J. K. Gaydos. 2012. Mortality related to Spotted Ratfish (Hydrolagus colliei) in Pacific harbor seals (Phoca vitulina) in Washington State. Journal of Wildlife Diseases 48:1057-1062. DOI: 10.7589/2011-12-348.
  2. Biology of Rays and Sharks; Chimaeras – The Neglected Chondrichthyans.
  3. Huber, D.R., Dean, M.N., Summers, A. P. 2008. . Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish Hydrolagus colliei
    Journal of the Royal Society Interface 5 (25), 941-953.
  4. Didler, D.A. Chimeras. 
  5. Doughton, Sandi. August 14, 2010. Rise of the Ratfish in Puget Sound. Seattle Times.
  6. Florida Museum of Natural History. Spotted Ratfish.
  7. King, J.R. & McPhie, R.P. 2015. Preliminary age, growth and maturity estimates of spotted ratfish (Hydrolagus colliei) in British Columbia. Deep Sea Research Part II: Topical Studies in Oceanography, 115: 55-63
  8. Klimley, Peter A. 2013.  The Biology of Sharks and Rays. The University of Chicago Press.
  9. Love, M. 2012. Certainly More Than You Want to Know About The Fishes of The Pacific Coast—A Postmodern Experience. Copeia:Milton S.Love Santa Barbara Really Big Press

Deep sea ROV video of what may be the species Pointy-Nose Blue Ratfish (Hydrolagus trolli) in the NE Pacific. Good general information on ratfishes in general and would mean a very significant range expansion for this species.

Remarkable Giant Pacific Octopus + Wolf Eel Encounter

Trust me, you are going to love the video below!

Giant Pacific Octopus passing over a mature male Wolf Eel in his den. See video below. ©Jackie Hildering

Giant Pacific Octopus passing over a mature male Wolf Eel in his den. See video below. ©Jackie Hildering

It is one of the most remarkable encounters I have witnessed in all my dives.

It’s a fortunate enough thing to be able to watch a large Giant Pacific Octopus when it is hunting. In this encounter, the octopus passes directly over a mature male Wolf Eel in his den. THEN, a Decorated Warbonnet emerges as well.

It was an exciting day in this wonderful marine neighbourhood.

I hope this 3-minute clip allows you to share in the awe and excitement.

For me, this was the NE Pacific Ocean equivalent of seeing a giraffe, elephant and rhino in close proximity.

Video and photos contributed by dive buddies Katie Morgan and Diane Reid while on our trip with God’s Pocket Dive Resort.

  • For more information on Wolf Eels (including that they are not an eel at all), see my previous blog here.
  • For more information on Giant Pacific Octopuses, click here for previous blogs and here for a blog specifically on hunting in Giant Pacific Octopus.

Fishy Fathers

There’s a whole lotta fish procreation going on in the NE Pacific Ocean right now. This might be a surprise to those who think mating is more of a spring-fling-kinda-thing.

It may be a further surprise that, for many marine fish species here, the males are the protectors of the next generation. The females leave after laying the eggs and the males remain, guarding the fertilized eggs from predators and often also fanning the eggs to ensure they are well aerated.

For a lot of these fish species, the male chooses the nesting site and entices multiple females to lay eggs there so that he can fertilize them. He then has the work of guarding these multiple egg masses and may need to be on the alert for sneak fertilization attempts by other males.

For species with nests of multiple egg masses, you can often tell how many females have laid eggs there because individual females have different coloured eggs. Therefore, the colour of fish eggs is not a good characteristic to determine the species that laid them. Instead, do a quick scan, chances are a piscine papa is somewhere near the eggs, staring at you.

Through the photos below, meet some of these fabulous fish fathers. No deadbeat dads here!

[Note that this is in no way a comprehensive list of NE Pacific Ocean fish species in which the males guard the eggs.]

Whitespotted Greenling

The encounter documented below shows how my dive buddy and I recently had a whitespotted greenling come after us, so intent was he on protecting his egg masses. I was very slow in cluing in that this was why he was swimming around us and deserved getting a little nip in the head.  Notice how small he is relative to us and yet how this did not deter him in trying to get rid of us.

Male White-Spotted Greenling shortly after he nipped my big head in his intensity to guard his egg masses. © 2013 Jackie Hildering

Male Whitespotted Greenling shortly after he nipped my big head in his intensity to guard his egg masses. © 2013 Jackie Hildering

Dive buddy Jacqui Engel pointing at the male White-Spotted Greenling before we clued in and got out of his territory with eggs. Image shows small the fish is compared to us and how big his drive to protect the egg masses that he would come after us. © 2013 Jackie Hildering

Dive buddy Jacqui Engel pointing at the male Whitespotted Greenling before I clued in and got out of his territory with eggs. Image shows how small the fish is compared to us and how big his drive to protect the egg masses must be that he would pursue us like he did. © 2013 Jackie Hildering

Male White-Spotted Greenling intensely guarding eggs. © 2013 Jackie Hildering

Here he is intensely guarding eggs. © 2013 Jackie Hildering

Whitespotted greenling (Hexagrammos stelleri)
Maximum recorded size: 48 cm
My observations of egg guarding on NE Vancouver Island: September to December

Kelp Greenling

Most often Kelp Greenling eggs are in the empty shells of giant barnacles as shown below. Although they are a bigger member of the Greenling family, male Kelp Greenlings do not appear to protect their eggs quite as vigorously as Whitespotted Greenlings. They appear to have a really long breeding season in our area.

Male Kelp Greenling © 2013 Jackie Hildering

Male Kelp Greenling. © 2013 Jackie Hildering

Eggs the male Kelp Greenling was guarding. Most often in giant barnacle tests (shells) like this. © 2013 Jackie Hildering

These are the eggs that the male Kelp Greenling in the above image was guarding. The eggs are most often laid in giant barnacle tests (shells) like this. © 2013 Jackie Hildering

Kelp Greenling (Hexagrammos decagrammus)
Maximum recorded size:61 cm
My observations of egg guarding on NE Vancouver Island: October to March
TMD slide show: Courtship Display in Kelp Greenlings 

Red Irish Lord

Oh Red Irish Lords how I love thee. There is no better ambassador for how colourful life is in these waters since they are brilliant shades, yet astoundingly camouflaged. Red Irish Lords are often easier to find when guarding their eggs since these are less camouflaged. They most often egg guard with their heads positioned right atop the eggs, remaining absolutely motionless. It is commonly believed that the fathers guard the eggs but apparently it is more often the mothers but that the parents may take turns. Source: DeMartini and Sikkel 2006: ” Red Irish Lord exhibits primarily maternal and facultatively biparental guarding of the spawn.”

Another male Red Irish Lord guarding an egg mass - note the very different coloured eggs from the previous image. © 2013 Jackie Hildering

Red Irish Lord guarding an egg mass – note the very different coloured eggs in the following image. © 2013 Jackie Hildering

Male Red Irish Lord guarding egg mass. © 2013 Jackie Hildering

Red Irish Lord guarding egg mass. © 2013 Jackie Hildering

Red Irish Lord (Hemilepidotus hemilepidotus)
Maximum recorded size: 51 cm
My observations of egg guarding on NE Vancouver Island: December to May
Previous TMD blog item on the species: In the Eye of the Lord (the Red Irish Lord That Is!)

Buffalo Sculpin

There are Buffalo Sculpin males guarding eggs at this time of year too but more mating appears to be happen in April and May. Usually, Buffalo Sculpins are even harder to spot than their Red Irish Lord cousins but the variably coloured, bright egg masses give away their location. They too have a strategy of staying right atop the eggs and remaining motionless when faced with annoying human divers.

Male Buffalo Sculpin guarding two egg masses - each from different females. © 2013 Jackie Hildering

Male Buffalo Sculpin guarding two egg masses – each from different females. © 2008 Jackie Hildering

Male Buffalo Sculpin guarding egg mass. © 2013 Jackie Hildering

Male Buffalo Sculpin guarding egg mass. © 2007 Jackie Hildering

Buffalo Sculpin (Enophrys bison)
Maximum recorded size: 37 cm
My observations of egg guarding on NE Vancouver Island: January to May
Previous TMD blog item on the species: Buffalos Mating Underwater

Lingcod

Soon we will be participating in the Vancouver Aquarium’s annual Lingcod Egg Mass Count. Armed with an underwater slate, we will join divers along the Coast in helping determine the health of lingcod populations by looking at the number and size of the egg masses and if they are being guarded by males. And oh what fastidious fathers lingcod males are! The dedication to protecting the egg masses does vary from male to male but, generally, they do not leave their watch until the eggs hatch which can be more than 24 days. They could be guarding masses from multiple females separated by more than 7 m, and if laid by a female 5 years old and older, the egg masses can be the size of a watermelon and weigh up to 14 kg! That’s a lot to protect! (As is also the case for many rockfish, the older the female lingcod, the more eggs she lays). My best lingcod story is that I was marking down “unguarded” on my slate only to have it knocked out of my hands by the male that was very much guarding the egg mass I had been observing! Lots more info on this species at my blog item Lingcod – Fastidious Fanged Fathers

Lingcod male guarding egg mass (with a couple of shrimp on his back). © 2013 Jackie Hildering

Lingcod male guarding egg mass (with a couple of shrimp on his back). © 2013 Jackie Hildering

Lingcod male guarding egg mass. Photo focus a bit fuzzy but the battle wound reveals the perils of egg guarding. © 2013 Jackie Hildering

Lingcod male guarding egg mass. Photo is a bit fuzzy but the battle wound reveals the perils of egg guarding. © 2007 Jackie Hildering

Lingcod (Ophiodon elongatus)
Maximum recorded size: 152 cm
My observations of egg guarding on NE Vancouver Island: January to April (Vancouver Aquarium’s Egg Mass Survey is from early February to the beginning of April).
Previous TMD blog item on the species: Lingcod – Fastidious Fanged Fathers 

Wolf Eel

Here’s a case where it is not just the male that guards the eggs. Mr. and Mrs. Wolf Eel take turns wrapping their long tails around the large egg mass. I hope to one day have the opportunity to get a better image than this but, as a strategy for survival, the egg mass is often deep within the wolf eel couple’s den. Lots more information on this remarkable species at my previous blog item Wolf Eel – No Ugly Fish!

Mr. and Mrs. Wolf Eel sharing duty in taking care of the egg mass. © 2013 Jackie Hildering

Mr. and Mrs. Wolf Eel sharing duty in taking care of the egg mass. Female on left and male on right. © 2005 Jackie Hildering

Wolf Eel (Anarrhichthys ocellatus)
Maximum recorded size: 2.4 m
My observations of egg guarding on NE Vancouver Island: October to January
Previous TMD blog item on the species: Wolf Eel – No Ugly Fish! 

Cabezon

I’ve only once been lucky enough to find a male of this huge sculpin species guarding eggs. They can apparently be very aggressive guarders but this very successful male (he was guarding the eggs of several females) was very tolerant of my presence. They have been documented to mate throughout the year. My one encounter with a male cabezon guarding eggs was in May.

Male Cabezon guarding egg masses from multiple females (egg masses different colours). © 2013 Jackie Hildering

Male Cabezon guarding egg masses from multiple females (egg masses different colours). © 2013 Jackie Hildering

Cabezon (Scorpaenichthys marmoratus)
Maximum recorded size: 99 cm

Painted Greenling

In all these years of diving, I have yet to find a male painted greening guarding eggs so that I know for sure the eggs are from this species. Yet something else to be on the lookout for!

Painted greenling. © 2013 Jackie Hildering

Painted greenling. © 2013 Jackie Hildering

Painted Greenling (Oxylebius pictus)
Maximum recorded size: 25 cm

Grunt Sculpin

And, the stuff of dreams  . . .  to one day chance upon a male grunt sculpin while he is releasing the hatching eggs from  . . . his mouth! For more on that, see my previous blog item Grunt Sculpin – Little Fish, BIG AttitudeThe females apparently also do take on shifts in taking care of the eggs.

Grunt Sculpin. Most often found in empty barnacle tests (not cups!) © 2013 Jackie Hildering

Grunt Sculpin. Most often found in empty barnacle tests (not cups!) © 2013 Jackie Hildering

Grant Sculpin (Rhamphocottus richardsonii)
Maximum recorded size: 8.9 cm
My observations of egg guarding on NE Vancouver Island:
Previous TMD blog item on the species: Grunt Sculpin – Little Fish, BIG Attitude 

You need not be a diver to see the eggs of the following two species.
While carefully lifting up rocks in the intertidal during the Spring, you might
come across these egg masses and possibly even the male guarding them. 

Scalyhead Sculpin

I have never seen scalyhead sculpin eggs while diving, likely because they are hidden away and because they are much smaller. The image of the eggs below was taken during a beach walk where students ensured they put the rock back as best they could to reduce the chances of the eggs drying out. Notice the different colours of the looney-sized egg masses? The eggs in this nest are from at least 4 females.

Male Scalyhead Sculpin in a giant barnacle test. © 2013 Jackie Hildering

Male Scalyhead Sculpin in a giant barnacle test. © 2013 Jackie Hildering

Egg masses from at least 4 different female scalyhead sculpins (each female's eggs have a different colour). © 2013 Jackie Hildering

Photo taken while on a beach walk. Egg masses found under a rock and they are from at least 4 different females (each female’s eggs have a different colour). © 2010 Jackie Hildering

Scalyhead Sculpin (Artedius harringtoni)
Max size: 10 cm
My observations of egg guarding on NE Vancouver Island: Spring
Previous TMD blog item on the species: Who’s Your Daddy

Black Prickleback

If you find an ice cream scoop mound like this, you have likely found the eggs of the black prickleback and the guarding male is likely very near. When taking students on beach walks, I emphasize the importance of not displacing animals by using this species as an example. Fish like the black prickleback are adapted to being able to wait out the tide in very little water and if the well-intentioned pick up the fish to put him in deeper water, they could be moving papa away from the eggs he was guarding.

Male Black Prickleback guarding egg mass in a tide pool. © 2013 Jackie Hildering

Male Black Prickleback guarding egg mass in a tide pool. © 2013 Jackie Hildering

Black Prickleback (Xiphister atropurpureus)
Max size: 32.7 cm
Records of egg guarding on NE Vancouver Island: Spring

Sources:

A World Without Salmon . . . .?!

 Spawning Sockeye salmon © 2006 Bruce Paterson

Spawning Sockeye salmon ©2006 Bruce Paterson

Dear readers, the following is a rework of a little rhyme I wrote in 2009.

Many of you will recall that 2009 was such a bad year for wild salmon in British Columbia that it led to the $26 million Cohen Inquiry into the Decline of the Fraser River Sockeye.

 Spawning Sockeye salmon © 2006 Bruce Paterson

Spawning Sockeye salmon ©2006 Bruce Paterson

And yet, there has been no solid action on the 75 recommendations resulting from that Inquiry and government has yet to take any sort of dedicated or meaningful action for the wild salmon – and all that depends on them.

The attempted messaging in my little poem may be all the more relevant now with the threat of tanker traffic coming to our fragile Coast.

The good news, I believe, is that with such threats more and more of us are united in understanding that, while resource use is a necessity, it has to be sustainable. It is impossible to have infinite economic growth on a finite planet.

With sincere apologies to Dr. Seuss:

A world without salmon would be oh so sad,
This is very important, so listen here Dad!

Without salmon, we will have broken the link,
That Nature intended to keep us in the Pink.
(And Sockeye, and Chum, and Chinook and Coho!)

Salmon bring the wealth of the ocean back to the Coast,
Right back to their birthplace so without them – we’re toast!

Their bodies are gifts to the future – that’s really key,
Delivering food for their babies and even the trees.

They feed fish-eating orca, sea lion and eagle,
Wolf, seal, deer, shark and . . . an occasional beagle!

They help bring the tourists. They fill fishers’ nets.
There ought to be enough so that all needs are met.

So little investment, so great the return.
Safe passage, and food – this, salmon surely earn?

But, instead of precaution, loud voices at desks,
Say, “Why it’s Nature that’s made this big mess.”

“It’s salinity, cycles . . . the phase of the moon!
Or some other reason we’ll think up real soon.”

What possible gain would justify such a gamble?
The cost of losing wild salmon would be so substantial.

Without salmon, grizzles stare into empty rivers,
No fat salmon to save them from winter shivers.

The orca diminish without their Chinook,
Peanut-shaped foreheads reveal this tragic truth.

And Bobby and Susie and even Aunt Myrtle,
Are left holding fishing poles, till they turn purple.

Shhhh can you hear that? No, I don’t hear a thing,
For without salmon, birds around rivers don’t sing.

The People of the Salmon were able to thrive.
Dance, song, carvings  . . . the wisdom to know what keeps us alive.

Salmon are the glue in a vastly connected web,
Why without them big trees would even be dead.

Then, there goes habitat, oxygen production and buffering of greenhouse gas.
Why to flirt with the health of salmon you would really have to be an  . . . . (you know).

The survival of salmon shows how we humans are doing.
Do we know our place on the planet? No. Nature is booing!

The solution is simple. It really isn’t hard.
It’s not tree hugger verses resource user. Let down your guard!

Logger, storekeeper, teacher, and you under that streetlight!
We keepers of paradise need to unite in what’s right.

Make a stand for the salmon, the whales, wolves and Coast.
We all know clean water and food is what matters most.

Choose for sustainability, not short-term economic gain.
Otherwise explaining things to our children could really be a pain.

Use vote, vision and voice, to help wild things grow.
And when it comes to gambling with salmon – just say “No!”

Then, because a whole lot of us care a whole awful lot,
It will be clear that BC’s natural splendour can’t be bought.

The importance of salmon ©2016 Jackie Hildering

The importance of salmon ©2016 Jackie Hildering

Since writing this blog, I have been asked “Salmon feed trees?”. Indeed, when they spawn in their natal rivers which can be more than a 1,000 km from the sea, salmon bring the richness of the ocean not only to animals but to plants.  The nutrients from their bodies feed the trees and plants including  . . . salmon berry! Animals like bears further the reach of salmon nutrients by taking spawned-out salmon from the rivers deeper into the forest where they can feed undisturbed. They eat their favourite bits and leave about 50% of the carcass in the forest which benefits the plants, song birds, and even animals like pine martens. Of course, bears also poop in the woods, which leaves more salmon nutrients in the forest. So the bears are like gardeners, bringing fertilizer much deeper into the forest!

It was initially Tom Reimchen’s research of the early 1990s that brought the knowledge of “Salmon Forests” to the world. He quantified how much salmon was in the trees by measuring the amount of “marine derived nitrogen”.  That research has expanded to where nitrogen and carbon isotopes are measured to quantify the uptake of salmon-derived nutrients by mosses, herbs, shrubs, trees, insects, songbirds, and wolves. So while salmon don’t grow on trees  . . . trees most definitely grow on salmon.

This knowledge solved the mystery of how you can have giant trees in a rain forest when nutrients get washed away by the rain. It’s the salmon who replenish the nutrients by delivering the richness of the sea through their spawning behaviour – just the way Nature intended. And of course, without those giant trees – imagine the reduced habitat and production of oxygen and buffering of carbon dioxide.

This makes clear how far reaching the role of salmon is; how interconnected the web of life is, and just how much depends on the health of wild salmon.  No better man to fully explain this “exquisite interconnectedness” than Dr. David Suzuki. See the 5 minute clip below. There is also a David Suzuki children’s book called “Salmon Forest.”

I have also been asked, “Deer eat salmon?!” They do. They feed directly on the spawned out carcasses of salmon and also benefit indirectly by feeding on the vegetation that has been fed by salmon.

Wolf-Eel – No Ugly Fish!

Don’t say it, please don’t say it. This is not an ugly fish. It hurts when people say this about Wolf-Eels. Such is the way when there is misunderstanding and disrespect for something you love. There is no ugly in Nature – only perfection. If the features of an animal appear foreign to you, it is because it fulfils a role in Nature that is truly awe-inspiring; possibly even beyond your imaginings.

Mr. and Mrs. Wolf Eel on February 16, 2013 near Port Hardy. © 2013 Jackie Hildering

Mr. and Mrs. Wolf-Eel near Port Hardy ©Jackie Hildering.

I hope to make this point by sharing with you why the Wolf-Eel  is “designed” as it is and how very wrong many of us are in our perceptions about this species. The Wolf-Eel (Anarrhichthys ocellatus), which can be as long as 2.4 m, is not an eel. Wolf-Eels belong in the Wolf Fish family (Anarhichadidae). They are desperately misunderstood. Wolf-Eels are not dangerous nor “mean”. The opposite is true. They are reclusive, anything but ferocious, quite sedentary and slow moving.

Mature male wolf-eel - about 2.2 m long. © 2008 Jackie Hildering

Mature male Wolf-Eel, about 2 m long. Can be 2.4 m ©Jackie Hildering.

Yes, they have large, fleshy, ossified heads and the species has sharp teeth but this is so they can do what so few marine species can – they can feed on spiny sea urchins, snapping them effortlessly into pieces without suffering a single puncture. They also feed on other hard-shelled animals like shellfish and crabs. Even the roofs of Wolf-Eels’ mouths are impenetrable with ossified, tooth-like projections (see photo below).

Each wolf-eel has distinct spots around their eyes which helps recognize them as individuals. © 2012 Jackie Hildering

Mature males are bigger and have fleshier heads. Each Wolf-Eel has distinct spots around their eyes which helps recognize them as individuals ©Jackie Hildering.

The upper jaw of a wolf-eel. Impenetrable to even urchin spines! © 2005 Jackie Hildering

The upper jaw of a Wolf-Eel. Impenetrable to even urchin spines! ©Jackie Hildering.

To my knowledge there has never been an attack on a diver UNLESS, and here comes the predictable thing, we choose to habituate them. Wolf-Eels spend a great deal of time on the ocean bottom in dens where, as divers, we have the enormous privilege of  “visiting” the same spot and seeing the same individuals for years. It is not just their address that makes them recognizable as individuals. Each Wolf-Eel has a unique pattern of black spots near their eyes.

Grandpa Wolf-Eel on February 16, 2013 near Port Hardy. © 2013 Jackie Hildering

Grandpa Wolf Eel near Port Hardy ©Jackie Hildering.

Some divers choose to feed them, leading to the Wolf-Eels associating us with food and that’s where accidents can happen and where the wild behaviour that lets animals survive, becomes compromised. It also makes them tragically easy targets for any spear diver wanting to poach them. There is no legal fishery for this species but there is a demand for them in the Asian market which is why there are also attempts to farm Wolf-Eels i.e. aquaculture. Not surprisingly, Wolf-Eels might also be defensive when accidentally caught by anglers. I found one account from 1959 where a commercial fisherman was bitten and “The teeth penetrated the hip-waders and broke the skin on both sides of the ankle.”

Mature male bearing the scars of battle. © 2011 Gord Jenkins.

Mature male bearing the scars of battle ©2011 Gord Jenkins.

The mature males do carry battle wounds supporting that they don’t just hang out in dens waiting for a snack to come by, but rather that they will occasionally duke it out with other male Wolf-Eels.It was long thought that Wolf-Eels always mate for life but, this is not always the case. The males do compete for females who will sometimes opt to swap dens and go live with the competitor. Sound like any other species you know? Wonder if it happens at mid-life? 😉

Wolf-Eels have long-lasting pair bonds, coming together when they are around 4-years-old and having their first clutch when they are around 7. In aquariums, their life expectancy is known to be at least 28 years. Both male and female juveniles are brownish orange and look even more eel-like, lacking the big head of the adults. As adults, the females are smaller and a darker brownish grey (both remarkably camouflaged for when they are in their rocky dens).

They do also sometimes need to do battle for den space with a Giant Pacific Octopus.  This is likely another driver for the male’s having such fleshy heads – they are better able to survive the wounds inflicted by such battles.

Clearly, another unique feature about this species is their eel-like body. They are the only member of their family that have this body shape. The long tail serves in locomotion, powering them forward with big, slow, s-shaped waves while being stabilized with the long dorsal and pectoral fins (see video below). Having a long tail also allows them to den-up, curling up and around in narrow spaces between rocks and . . . wait for it . . . it lets them hold onto their eggs.

Mr and Mrs Wolf-Eel tending their egg mass © 2005 Jackie Hildering-

Mated pair tending their egg mass. Note how much darker and smaller the female is ©Jackie Hildering.

Female Wolf Eel guarding eggs. March 2016 @Jackie Hildering.

Female Wolf-Eel guarding eggs. ©Jackie Hildering.

Mating apparently most often occurs between October and December, with the female releasing eggs after the male prods against her swollen abdomen. He then wraps around her to fertilize the 7,000 to 10,000 white to yellow eggs that she will mould into a ball shape. This mass does not need to adhere to anything because the parents will take turns wrapping their tails around the mass, holding and turning it for good aeration until the +/- 3.5 cm young hatch some 13 to 16 weeks after fertilization.

Juvenile wolf eel. © 2010 Jackie Hildering-

Juvenile Wolf Eel ©Jackie Hildering.

The juveniles settle into the adult sedentary lifestyle between the ages of 6 months and 2 years (presumably dependent on food supply and den availability). One juvenile is even known to have travelled a minimum of 1,000 km; having been tagged in Port Hardy, BC and found back in Willapa Bay, Washington two years later. It was long thought that Wolf-Eels always mate for life but, this is not always the case. The males do compete for females who will sometimes opt to swap dens and go live with the competitor. Sound like any other species you know? Wonder if it happens at mid-life?

The Wolf-Eel is indeed akin to us in so many ways. It is a homebody that likes crunchy snacks and prefers that they come right by the front door; they are great parents and are docile unless fighting for home or partner. They invest in durable relationships and – they are only as strange looking as we terrestrial bipeds would appear to them.

And if all of that is not enough for you, see the photo below for the indisputable reasoning for by Wolf-Eels are NOT ugly fish!

Statler the Muppet is cute and loveable. Ergo - so are wolf-eels. Case closed!!

Statler the Muppet is cute and loveable. Ergo – so are Wolf-Eels. Case closed!!

 

Range: Sub-tidal to 226 m; Baja California (Mexico) to the Aleutian Islands (Alaska); west to Russia and south to the Sea of Japan.

Mr. and Mrs. Wolf Eel on February 16, 2013 near Port Hardy. © 2013 Jackie Hildering

Mated pair near Port Hardy ©Jackie Hildering.

Me and a mature male wolf eel.

Me and a mature male Wolf-Eel ©2012 Norris Colby.

Mature male wolf-eel. © 2007 Jackie Hildering

Mature male Wolf-Eel ©Jackie Hildering.

Mature male wolf-eel. © 2007 Jackie Hildering

Mature male Wolf-Eel ©Jackie Hildering

For these and more images of the Wolf-Eel, please see my gallery at this link. 

Remarkable video of a mature male Wolf-Eel eating a Giant Pacific Octopus by Andrew Eve.

Sources:

Grunt Sculpin – Little Fish, BIG Attitude!

Meet the fish that so often has people exclaiming “It lives HERE?!”

Yep, the tiny grunt sculpin is a powerful ambassador for raising awareness about the depth of biodiversity hidden in the cold, dark, rich waters of the north east Pacific. 

We are programmed to associate warm waters with exotic-looking fish species but read below for the Grunt Sculpin’s astounding adaptations and masterful mimicry. 

Grunt sculpin. Tiny fish. Giant attitude. ESPECIALLY the females. Photo: Hildering.

The species reaches only a maximum of 9 cm.

It is adapted to look like a giant barnacle (Balanus nubilis)!  When facing outward, its pointy nose looks like a closed giant barnacle and when the fish turns around, its tail looks like the foot of the barnacle that rakes in plankton.

Adapted to look like a giant barnacle! Huge thanks to dive buddy Natasha Dickinson for finding this one. Photo: Hildering.

This little fish has giant attitude. When not hidden away in a barnacle (or a cup, see photo), it can be highly territorial, hopping around on its pectoral fins in a strutting, jerky fashion. A lot of literature reports that the grunt sculpin is an “awkward swimmer” but I solidly disagree. I once saw one flash away with lightning speed back to its hiding place. Yes, I was being an annoying photographer.

If you can’t find an empty barnacle shell. A cup will apparently do! Photo: Hildering

Ah and you probably think the males are the master strutters? Ha! The female is as fierce as can be. She will aggressively chase a male into a crack, an empty barnacle shell, or other place of no escape and guard him there until she is ready to lay her eggs. When she has laid them, the male is released to do his duty.

She watches him to ensure he fertilizes the eggs (up to 150 at a time) and then, according to some sources – she saunters off but may return once in a while to take on a shift.  For many members of the sculpin family, the males are the sole egg guarders.  However, there are also reputable sources that report that the female grunt sculpin guards the nest of eggs.

Very young grunt sculpin. The red-gilled nudibranch in the upper part of the image is only about 2 cm long. Another great find by dive buddy Natasha Dickinson. Photo: Hildering.

It may even get to be more remarkable, one source relays that when the eggs are near hatching, the guarding grunt sculpin takes them into their mouth and spits them out into the open water. The suggestion is that this causes the eggs to hatch and the little zooplankton are sent on their way. (Source: Aquarium of the Pacific).

The grunt sculpin’s pointy “bill-like” head is reflected in the species’ scientific name. Photo: Hildering

With regards to classification, the scientific name Rhamphocottus richardsonii reflects the Greek “rhamphos” for the grunt sculpin’s bill-like snout. This makes some people think that the species looks like a seahorse but note that they are not closely related at all. The grunt sculpin is the only member of its genus. It is truly one of a kind.

Juvenile Grunt Sculpin #1 of 3 photos. ©2017 Jackie Hildering.

Juvenile Grunt Sculpin #2 of 3 photos. ©2017 Jackie Hildering.

Juvenile Grunt Sculpin #3 of 3 photos. ©2017 Jackie Hildering.

Oh, and the name “grunt” sculpin? Apparently the species grunts when it is taken out of the ocean. You would too! Likely it also grunts when being defensive underwater. It is also the sound I make in my delight when I find one. It will be a very loud grunt indeed if I ever find one guarding eggs or with its tail-end extended out of a barnacle.

Another very fortunate find of a grunt sculpin in a empty barnacle shell. Photo: Hildering

Grunt sculpin in a empty barnacle shell. Photo: Hildering

Plankton Got Sole!

No, I have not mixed up my spelling of “soul” verses “sole”.

Planktonic sand sole.  Only 2.7 cm. 
Click image to enlarge. Photo: Hildering

This last weekend, while watching herring feed on krill in a tide line, I suddenly noticed a very small transparent fish.

Upon closer inspection, I saw that it was a larval form of some species of flatfish.

I was able to dip the little guy into my dive mask for a few pictures and, due to the size of the lettering in the mask, I know that the fish was only 2.7 cm.

I was in awe of how transparent s/he was; that I could see the bones and heart; and that this small, fragile planktonic stage could ever survive to grow into an adult.

These sorts of “finds” are as awe-inspiring to me as any sighting of a whale. The thick planktonic soup of our rich cold oceans is full of the larvae of so many species. Anemones, nudibranchs, sea stars, crabs, etc. – they all start off as zooplankton and the incidence of what sort of plankton are present often gives scientists an indication of what may be happening with the marine food web.

It is like a world of hidden secrets to me and of course I wanted to find out all I could.

What species of flatfish was this – halibut, sole, flounder?

Click image to enlarge.
Photo: Hildering

I do not have the expertise to know but, oh so thankfully, there are those out there willing to share their great knowledge.

Marie-Josée Gagnon of the Salmon Coast Research Station quickly steered me in the right direction, believing it was most likely a species of sole.

She connected me with zooplankton taxonomist  Moira Galbraith of the Institute of Ocean Sciences who confirmed that this was the larval form of a Pacific sand sole (Psettichthys melanostictus), a species that can grow to 63 cm. She also shared that the transparency of the larval fish serves as camouflage, reducing the chances of it being eaten before reaching the life stage where it settles to the ocean bottom and hides on and in the sand.

But wait, what are those two little zooplankton guys attached to the larval sole? They are copepods, but what kind of copepod?  What does their presence mean ?  Are they parasitic? And there I go down the marine id rabbit hole. 

One thing I know for sure though – and forgive me for the following pun because the emotion behind it is very sincere – how I hope this little planktonic fish will be a  . . . sole survivor.

Video of flatfish larval development (images by Dr. Alexander M. Schreiber.)

Sources:

Update September 30, 2012:

  • This great item by Puget Sound Sea Life has been brought to my attention and includes the following: ” . . . within several days to weeks, depending on the species, the larva undergoes a radical metamorphosis. The right or left eye migrates from it’s normal position across the top of the head to the other side of the body changing some skull bones in the process . . . . After metamorphosis, the fish settles to the bottom on it’s left side, develops skin color on the right side and continues growth as a juvenile.  Adapting a bottom-dwelling life style allows flatfish to exploit a common habitat – flat sandy bottoms which are very common in the subtidal zone. Many fish avoid this habitat because of the lack of rocks or other features that would provide a hiding place. Flatfish can hide from predators by burrowing, leaving only their eyes above the surface. In addition the habitat is home to an abundance of prey such as worms and shrimp. With both eyes on the upper side they can use 3D vision to hunt and detect predators. There has been considerable controversy over the origin of flatfish, but recent discoveries of several fossil intermediate forms show that eye migration evolved gradually some fifty million years ago.”
  • With regard to the ectoparasites on the sand sole larva, Marie-Josée Gagnon and Moira Galbraith have again been very generous with their knowledge. It is impossible to know the species from my photo but, due to the size, it is likely a recent infection and could be (1) first stage Chalimus; (2) Lepeophtheirus bifidus – which, unlike most parasites of benthic marine species is host specific – only being found on the rock sole or possibly, (3) the isopod Gnathia.   I valued having affirmed too that adults and young live in different environments to eliminate competition for the same resources but also to provide a buffer or separation to prevent transfer of disease or parasites.

Rockfish Barotrauma

Here’s another case of a photo being worth a thousand words.

It is of a Yelloweye Rockfish that has died from barotrauma aka “pressure shock”. 

Many rockfish species are particularly sensitive to reductions in pressure since the air in their swim bladders expands substantially. The swim bladder is a buoyancy control organ and even when slowly reeled in from a depth of only 20 m (60’), a rockfish’s swim bladder can expand to three times its size, putting pressure on the fish’s organs.

As is the case with the Yelloweye Rockfish in the photo, the swim bladder can expand to the point of causing the fish’s eyes to bulge out of their sockets and its stomach to be pushed out of its mouth. I know this is likely a sight that may not enhance your appetite for your rockfish catch but please read on since, contrary to the thinking of many, this IS reversible whereby the rockfish stands a good chance of survival.

Yelloweye Rockfish that has died of barotrauma. Reduced water pressure causes the air in the swim bladder to expand and push out the stomach and eyes. BUT this is a reversal condition whereby the fish can survive through use of a “fish descender”. Photo: Hildering. 

Colossal management errors were made with overfishing slow-growing rockfish. Many species are extremely long-lived, slow to sexually mature, and the big, old females are the most fertile – producing the most eggs and hatching the largest number of healthy young.

For example, Yelloweye Rockfish are believed to have a lifespan of up to 118 years, don’t reproduce until they are at least 12 years old, and the old females can incubate up to 2.7 million eggs!

This means that species are very slow to reproduce whereby, if you catch lots, especially the big females, you can devastate populations very quickly.

Another nail in the coffin of rockfish is that many adults also have high site fidelity so that by fishing one area, you can wipe out a community of fish. This is why Rockfish Conservation Areas (RCAs) are essential, where it is illegal most often to do any hook and line fishing (see restrictions here). 

But, what is you accidentally catch a rockfish outside these areas and do not wish to retain it, or you have already caught your fishing limit? 

There are studies that prove that if you were to quickly recompress the fish, it would stand a very good chance of survival, even where it appears dead at the surface (see video below). The fish could be brought back to depth with barbless weighted hooks, commercial “fish descenders” (cost is only about $6), or even by inverting a weighted milk crate over the fish! 

This video makes the life-saving potential of fish descenders very clear.

How wonderful it would be if more people would undertake the effort to recompress the fish, knowing how dire the situation is for many rockfish species. Imagine the further positive impact if people would choose to return the depleted species to depth even when they haven’t reached their catch limit, especially the big, highly productive females.

But, even if there was to be such enlightenment, many rockfish populations are so depleted that they need far more protection.

Again, Rockfish Conservation Areas (RCAs) are essential. These should be areas known to be the territory of depleted rockfish populations. Since these are no-fishing zones, there is no chance of barotrauma and the rockfish populations that live in the area are given the time to rebuild to have more sexually mature fish and more big old super mamas.

In summary – it’s so easy to make a positive change: (1) respect Rockfish Conservation Areas knowing that you usually cannot do ANY hook and line fishing there; and (2) invest in a fish descender for rockfish caught outside RCAs.

Long live rockfish!

Links:

Fantastic video showing how rockfish that appear dead at the surface due to barotrauma fully can revive at depth! From the Coastside Fishing Club:

Entertaining and super informative video “How to save a life – a rockfish life” by fish guru Milton Love with a rap song by Ray Troll: