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

Posts tagged ‘camouflage’

Gunnel, Gunnel, Gone!

Meet the Penpoint Gunnel, another fabulous fish face and master of camouflage.

The colour of Penpoint Gunnels varies as much as the colour of seaweed . . . from olive green, to golden brown to red. In fact, the colour of Penpoint Gunnels is generally such a perfect match to their seaweed habitat, that they sometimes seem to disappear into it. Presto – gone!

I recently met the individual in the photo above. We were in the surf zone at about 3 metres depth, the water above our heads crashing against the rocks. One of us was way better adapted to go with the flow. It wasn’t me.
Penpoint Gunnel is Apodichthys flavidus to 48 cm long.

There’s a great paper from 1966 by Don Wilkie on the colour of Penpoint Gunnels. An interpretation of the paper by FISHBIO includes: “The coloration of adult penpoint gunnels typically matches the dominant algal community of their habitat. Green individuals are found in the upper intertidal zone where green algae (and eelgrass) is most common, brown specimens most frequently occur in the mid-to-lower intertidal zone where brown algae mainly occurs, and in deeper water where red algae become increasingly prevalent, penpoint gunnels tend to be red as well.”

Here’s a mystery. Penpoint Gunnels CAN’T change their colour to match their surroundings. So how can they have the variety of colour and be so well-matched to their habitat, as is evident in my photos below? Read on!



How can they be such a match to the algae when they cannot change their colour? Is colour determined through the genetics of their parents? Research suggests not! Is it determined by their diet when they are adults? Also no!

It appears that the colour is determined by (1) the vegetation upon which the transparent / colourless larvae settle and/or (2) by which amphipods the larvae eat.

From Wilkie: “Field and laboratory studies were undertaken to examine the ecological role of colouration in the penpoint gunnel Apodichthys flavidus . . . A. flavidus was found to prefer cover under rocks to that within vegetation, but when provided with vegetation alone chose that which it matched. The colour phases observed in A. flavidus were found to be determined directly by the pigments they contained not by differences in stages of chromatophore expansion . . . . Colour change experiments showed that A. flavidus cannot undergo complete changes of colour phase in response to environment alone. Diet has an influence on colour, but complete colour changes were not produced experimentally.

Larvae were reared from the eggs of green and brown individuals. All developed colouration more similar to that of the Artemia [brine shrimp] upon which they were fed than to their parental type . . . It is suggested that the colouration of A. flavidus has a cryptic function which is of importance primarily during food seeking. It is hypothesized that the vegetation upon which A. flavidus larvae settle in conjunction with early diet primarily determines the colouration of individuals.

So, while Penpoint Gunnels cannot change colour, they appear to be able to recognize and select the vegetation for which their colour is a good match. What this also suggests is that the depth where an individual started of his/her life as a larva, will be the depth where they would/should live out their life.

As described above, because of the limits of how deep wavelengths of light can travel, there are zones of seaweeds / algae. Green seaweeds are in the shallows, then there are brown seaweeds, and then red seaweeds are the deepest (their pigment can best absorb the blue-green light that can penetrate to greater depths). If a Penpoint Gunnel started off as a larvae feeding on amphipods that are well-matched to green seaweed, the research supports this is what would make them green coloured. If that individual moved deeper into the brown or red zone, they would not have the appropriately coloured seaweed to match their colour.

ID Challenges

It can be wonderfully difficult to discern Penpoint Gunnels from the other gunnel species off the coast of British Columbia (6 species total).

If you get a really good look at the back end of a Penpoint Gunnel, that really helps in IDIng the species. The “penpoint” refers to the first spine of the anal fin. It’s large and grooved like a fountain pen point. Yes, I know that most often that ID tip is not really going to help with a live individual. ūüôā

I find it the most difficult to discern Penpoint Gunnels from Crescent Gunnels (Pholis laeta to 25 cm) and Saddleback Gunnels (Pholis ornata and 30 cm). Those species also have a wide variety in colour and have the black bar by their eye and, Penpoint Gunnels also can have markings along their backs. I don’t believe it is known how their colour of Crescent and Saddleback Gunnels is determined.

Then there are also Rockweed Gunnels, Longfin Gunnels, and Red Gunnels off the coast of British Columbia. Oh, and there are other elongate fish found in similar habitats, like species of prickleback and cockscomb!

The next six photos are included to maybe help with IDing gunnels. They are all NOT Penpoint Gunnels.

Then, at the end of the blog, there’s a fun fishing finding venture for you.

Who goes there? I initially had this individual identified as a Penpoint Gunnel but was thankfully corrected by Andy Lamb. He pointed out that this is either a Crescent or Saddleback Gunnel because there are pale bands adjacent to the dark ones through the eyes.
Crescent Gunnel – common name is for the crescent-like markings along the back.
Another Crescent Gunnel. You can see the crescent-like markings better with this perspective.
Ths is another Crescent Gunnel and here you can see that there are very tiny pelvic fins in front of the pectoral fins (that little bump). Penpoint Gunnels do not have those.
This is NOT a Crescent Gunnel. Andy Lamb let me know this is a Saddleback Gunnel because Saddleback Gunnels have darker stretches between the markings along their backs and because these markings are more saddle-shaped than crescent-shaped. Sure, that should help! You say saddle. I say crescent!
Er sorry – things are even more fun. This is not a Penpoint Gunnel, nor Saddleback Gunnel, nor Crescent Gunnel. It’s a Longfin Gunnel (Pholis clemensi to 13 cm long). How to know when colour and the markings along the back are similar to other species? There are those little dots along the midline of the fish. Yes, it’s often a combination of features that help determine the ID.

Find the Fish!

Many of you may know that every Friday I do a “Find the Fish Friday’ challenge and have two children’s books by the same name. These are the “Where’s Waldo” of the fish world with the intent being that, when people search for the fish in my images, they are also absorbing what the life looks like in the dark, rich Northeast Pacific Ocean.

Below are two such challenges where there is one fish to be found in each photo and it is a Penpoint Gunnel. At the very end of the blog I reveal the location of the fishes. Enjoy!


Summary for Penpoint Gunnels

Species information from “Certainly More Than You Want to Know About the Pacific Coast” by Dr. Milton Love includes:

Maximum length to 46 cm. The Ranges: Kodiak Island to Santa Barbara and Gaviota (Southern California). They are abundant from at least Prince William Sound (northern Gulf of Alaska) to Central California. Intertidal to 8, including tide pools. Most fish live int he intertidal or barely subtidal . . .

Penpints are long, thin, and eel-like, distinguished by a deeply grooved spine on the front of the anal fin (hence the name “penpoint”), a line extending downward through the eyes, and no pelvic fins. The body colour is highly variable: orange, red, and magenta, bright green, olive, or bronze. While usually a solid colour, the body can be highly mottled, with a row of dark or light spots along the midline . . .”


Answers to the two Find the Fish challenges above

This was the very same fish as in the first photo in this blog. I photographed him/her in April 2021 in Browning Pass.
This little guy/gal was in only about 2 metres depth beside a boat ramp in Port Hardy. This is one of the challenges included in my first Find the Fish book.

Sources

Crabs Making Bad Choices

[Update: Species corrected thanks to Greg Jensen. I initially posted that the crab in the first 3 photos was a Moss Crab].

How do crabs make bad choices?

Let me show you via my photos and a “conversation” with the crab in the next three photos.

 

Oh hello mature male Sharpnose Crab. I almost didn’t see you there!

Please may I take a photo of how you have fabulously decorated yourself to camouflage against predators, using bits of algae, sponges, tunicates and hydroids?

It’s fascinating how your species, and others who decorate themselves, have little hooks (setae) on your exoskeleton to which attach life from around you AND that you change outfits when your change backgrounds. Do you sometimes also use the camouflage as easy-to-reach snacks?

 

Oh, oh! Wait!

You don’t know you are walking onto the head of a Red Irish Lord, an ambush hunter who is extraordinarily camouflaged too.

 

 

Careful! You are on the menu for this fish species.

The Red Irish Lord will try to grab you, ideally from the back of your shell. That’s what happened to the crab in the next two photos.

 

Indeed, that’s the same species of fish. Red Irish Lords have incredible diversity in colour to blend in so that you, and I, have great difficulty detecting them.

When the fish does not have the advantage of a sneak attack, you can defend yourself by spreading out your claws really wide. Like what you see below.

Then, it’s difficult for the Red Irish Lord to fit you into his / her mouth.

 

Yes, I too imagine the crab in the above two photos saying, “You want a piece of me?!”

It’s said of your species that you “put little effort into decoration”. Such judgement!

In another species, the Moss Crab, a correlation has been found between size and how much decoration there is. Once big, especially with claws spread wide, mature male Moss Crabs cannot easily be gulped up whereby there is less need for camouflage. But mature male Moss Crabs are huge! Up to 12.3 cm just across their carapace. Your species, the Sharpnose Crab (Scyra acutifrons) is only up to 4.5 cm across the carapace. Mature males of your kind have a far greater reach with their claws than mature females.

By the way what’s with the posturing with mature males of your kind when they do what is shown in the photo below?

Yours is NOT the only crab species that can be gulped up. I think it might be a Graceful Kelp Crab who has been engulfed by the Red Irish Lord below.

 

Below is another crab in danger of making a fatal choice as it advances down the face of the Red Irish Lord. See how precarious this is? The fish will remain motionless, waiting, waiting till you are in the ideal position to ambushed from behind. Then your claws are of little use to you.

 


There you go dear human readers.

I do not know the fate of either of the crabs on the heads of the Red Irish Lords. I had to return to the world where we humans can also make really bad choices.

Why no, my referencing human bad choices on November 4th 2020 is purely coincidental. Insert innocent eye batting here. What choices could I POSSIBLY be referencing? ‚ėļÔłŹ

Be kind. Be colourful. Be careful. Be truthful. Be safe.¬† ūüíô

Regarding the photo above, see the Red Irish Lord and the two crabs with outstretched claws?


Related TMD Blogs:


Sources: 

Drake, Catherine Anne, “Decorating Behavior and Decoration Preference in the Masking Crab, Loxorhynchus Crispatus” (2016). Capstone Projects and Master’s Theses. 74.

Jensen, Gregory. (2014). Crabs and Shrimps of the Pacific Coast: A guide to shallow-water decapods from southeastern Alaska to the Mexican border.

Wicksten, M. (1978). Attachment of Decorating Materials in Loxorhynchus crispatus (Brachyura: Majidae). Transactions of the American Microscopical Society, 97(2), 217-220. doi:10.2307/3225595

 

Find the Fish for Oceans Day

Here you have five Find the Fish challenges for Oceans Day. 

Background:

Photo to give a sense of the equipment needed to dive in cold water. Yes, that includes a tutu. 

You may be aware that I post one such search on social media every Friday (i.e a “Find the Fish Friday” challenge)
and that there are two Find the Fish children’s books as well.

The aim of these “Where’s Waldos” of the fish world, is to help create awareness of what it looks like below the surface of the dark, cold NE Pacific Ocean. So often we are presented with marine imagery from warm waters, not realizing that it is the cold, current-rich waters of the world that have more oxygen dissolved in them. More oxygen means more life and the resulting plankton soup makes this ocean appear dark. Thereby, the colour, beauty and fragility are hidden.

Often even adults do not realize they have a bias to thinking the marine life is “better” and more abundant in warmer water. But if it is easy to see deep into the water as it is in the tropics, this is because there is less plankton. If there is less plankton, there is less food to fuel the food web and there is also less oxygen production and absorption of carbon dioxide.

So here we go.

I will first show what the fish species looks like. I will then provide the challenge and then, a link to the answer.


Challenge #1:

This is a Red Irish Lord.

They can be 51 centimetres long and are incredibly good at camouflaging.

How is that possible when they are red, yellow, pink, orange and/or white? Because that’s how colourful the life around them is, so they blend in. They can be so many different colours and even their eyes have spots on them to help the camouflage.

Can you find the Red Irish Lord in the kelp forest in the picture below? If you click the photo you can make it bigger.

Click to enlarge.

Ready for the answer? Click here. 


Challenge #2:

You are searching for another Red Irish Lord in the picture below. Those anemones you see are the biggest in the world. They are called Giant Plumose Anemones and are up to 1 meter tall. Because there is so much oxygen and food in this ocean, there are many of the world”s largest marine species.

Click to enlarge.

If you are ready for the answer, click here. 

Think about why the Red Irish Lords are camouflaged and are most often motionless, not swimming around the ocean in schools like other kinds of fish. What advantages does it give them to behave like this.

You probably realized that it helps them hunt. They are ambush hunters which means they wait for a fish or crab to come by and then they grab it. I have even seen crabs walk right on the face of a Red Irish Lord.

In the picture below, see what the crab is doing? By making itself really big by spreading its claws, the Red Irish Lord will not be able fit the crab into its mouth!


When an animal is camouflaged, it has a better chance of being hidden from: 

1.  The animals trying to eat it (predators); 

2.  The animals it hopes to eat (prey); and

3.  Others of its kind that might compete for food or mating. 


Challenge #3:

This is a Longfin Sculpin. See the amazing colours and textures. It’s a smaller fish. Maximum size is to 15 centimetres.

Can you find a Longfin Sculpin in the photo below?
All those orange circles are animals. They are Orange Cup Corals.
The rocks are covered with species of coralline algae. Yes, this is a pink type of seaweed that forms crusts all over the rocks. 
The two white animals close together are a species of sea slug. They are called Yellow-Rimmed Nudibranchs. They are mating and the spiral you see is a ribbon of  their eggs. There are hundreds of tiny little eggs in that spiral and the babies will hatch into the ocean.

Click to enlarge.

For the answer showing where the Longfin Sculpin is, click this link. 

Longfin Sculpins look very different at night. They are among the local fish species that darken to match their night surroundings. This is called “nocturnal colouration”. You can see how very different Longfin Sculpin’s night colour is by going to my blog here.¬†


Challenge #4:

This is a Blackeye Goby.

They are up to 15 centimetres long.

In the picture below. There are two Blackeye Gobies. One is easy to find but you will likely have to search quite hard to find the second one. As you search, notice the Giant Nudibranch. Yes, another GIANT. This kind of sea slug can be 30 centimetres long. They can swim and they are also amazing predators. I have lost of information about them in my blog at this link.

There are also more Orange Cup Corals, some Tube-Dwelling Anemones and Purple Urchins.

Click to enlarge.

Answer time? Click here. 

Extra information about Blackeye Gobies:  They ALL start off as females and under the right conditions, will become male. The males are tidy housekeepers, cleaning out the sand form their den. They are highly territorial and come out of their tidy homes to attract multiple females. After mating, the father fish will guard the eggs of the multiple females: ~1,600 to 27,000 eggs at a time for10 to 30 days!.

Blackeye Gobies also change colour at night to blend in better with their background.


Challenge #5 – The SUPER CHALLENGE:

This is a Scalyhead Sculpin.

They are a small fish with maximum size being only 10 centimetres. They can be a lot of different colours and the mature males have what look like big bushy eyebrows (cirri).

They are INCREDIBLE at camouflaging. There can be so many is just one small area.
Think about how big the top of a school desk is. The photo below is of an area much smaller than that and there are TWELVE Scalyhead Sculpins here!
The crab you see is a Pygmy Rock Crab. They usually hide out in the old shells of Giant Barnacles and do not get bigger than about 5 centimetres.
If you can find even six of them you have done very well.

Click to enlarge .

The answer for the locations of all twelve of the fish is at this link.


I am hoping now that when you think of the bottom of the Northeast Pacific Ocean, you have a better idea of just how colourful it is. To be sure, please see the pictures below.

There are NO fish to find in these photos. ūüôā

Decorator Crabs! The best-dressed in the NE Pacific Ocean.

Are you ready? I’ve been collecting these photos for a long time. Now, finally, I think I have enough to deliver this marine fashion show to you – the best dressed of the NE Pacific Ocean!

Decorator crabs are camo-crabs. They pluck bits of life from their surroundings and attach it to themselves. AND, if their surroundings change, they change their outfit.

Graceful Decorator Crab covered with hydroids including the “Raspberry Hydroid” which was only recognized as a new species in 2013 with the area near Telegraph Cove (Weynton Pass) being one of the few areas these colonies are known to live. ¬©Jackie Hildering.

This is highly functional fashion. Not only does this covering of life allow the crabs to hide from potential predators, it also apparently changes the way the crabs feel and taste in a way that deters their predators. Sponges taste bad or are even toxic to many predators and animals like hydroids and other “cnidarians” have stinging cells. Thereby, if you cover yourself with sponges or cnidarians, predators be gone!

Graceful Decorator Crab adorned with “Strawberry Anemones” (not actually an anemone species but a “corallimorph”. ¬©2017 Jackie Hildering.

Indeed, even though decorator crab species look like walking gardens, often what they attach are not algae but other animals Рhydroids, sponges and bryozoans.

Additional bonuses of carrying other organisms on your back may be:

  • You have potential snacks within a pincher‚Äôs reach.
  • Your camouflage allows you to get closer to your prey.
  • You are carrying weapons!

From A Snail’s Odyssey: “Apart from passive camouflage from potential predators, other functions of the behaviour may include disguise for closer approach to prey, and provision of tools for active defense, such as a branches of hydroids containing functional stinging cells or pieces of sponges or tunicates containing toxic chemicals.”

Graceful Decorator Crab with snippets of sponge attached to his/her carapace (Hooded Nudibranchs in the background). This individual realized it had been seen and switched to the defence strategy of looking big since “so many fish predators are limited by the size of their mouths” (Source:¬†Crabs and Shrimps of the Pacific Coast);¬†¬©Jackie Hildering.

Note too that not all growth on the back of crabs is the result of decorating and remember that crabs moult, crawling out the back of their shells in order to grow. Also from A Snail’s Odyssey: ¬†“In some cases these camouflagings result from settlement of spores and larvae . . . . Passive buildup of growths is greater with increasing age as moulting frequency decreases.¬† Also, in many species there is a final or terminal moult which, if the species’ exoskeleton is receptive to settlement of larvae and spores, leads to an even greater build-up of cover.”

Graceful Decorator Crab adorned with (and atop of) Glove Sponge. ©Jackie Hildering.

“Spider crab” (superfamily Majoidea) species are the ones that most often adorn themselves. From Greg Jensen‘s Crabs and Shrimps of the Pacific Coast: “Many spider crabs . . . mask themselves with algae or encrusting organisms so that they can hide in plain sight. The decorator crabs are equipped with curved setae much like the hook part of Velcro fasteners: after shredding material a bit with their mandibles, they press it into place. The largest species tend to stop actively decorating once they outgrow most of their predators.”

Crab predators include the Giant Pacific Octopus and fish species like Cabezon, some rockfish, Surfperch, Wolf-Eel and the Staghorn Sculpin. Of course, at low tide, birds and mammals are also predators.

Hoping this adds to the wonder, connection and respect for our marine neighbours. Enjoy the rest of the show!

[For research on decorator crabs with great diagrams explaining how how attachment occurs see this link.]

Well that’s unique! Decorated with Sea Vases (species of tunicate). ¬©2017 Jackie Hildering.

Try not to smile!

Another Graceful Kelp Crab adorned with Raspberry Hydroids.

Here you can even see where the Graceful Decorator Crab has clipped off bits of sponge. AND s/he’s in the act of attaching clippings. ¬©Jackie Hildering.

Longhorn Decorator Crab. ©Jackie Hildering.

Heart Crab (I THINK) Рnot likely to have decorated itself but rather this is the result of the settlement and accumulation of organisms = a walking ecosystem. ©Jackie Hildering.

Graceful Kelp Crab with adornment of Sea Lettuce. ©Jackie Hildering

Graceful Decorator Crab in front of a Painted Sea Star. S/he had just moved from being camouflaged among kelp to moving in front of the sea star. ©Jackie Hildering.

This Graceful Decorator Crab has adorned him/herself with bits of Barnacle Nudibranch egg masses for camouflage. You can see the egg masses behind the crab.

Decorator crab species in the NE Pacific Ocean include:

  • Graceful Decorator Crab – Oregonia gracilis
  • Graceful Kelp Crab – Pugettia gracilis¬†
  • Longhorn Decorator Crab – Chorilia longipes
  • Other species too will sometimes put a bit of camouflage on their rostrum e.g. Northern Kelp Crab – Pugettia producta

Giant Pacific Octopus – Video

Giant Pacific Octopus subtly changing colour and texture. Video by Erika Grebeldinger.

Remarkable video of a Giant Pacific Octopus juvenile subtly changing texture and colour to better match its surroundings.

When full grown, this species can be over 7 m from arm tip to arm tip and over 73 kg = the biggest species of octopus in the world.

The video was taken by fellow Top Island Econauts Dive Club diver Erika Grebeldinger during one of our dives last month. It is testament to the calibre of her diving and concern for the environment that she was able to “capture” such natural behaviour. It the octopus had been agitated, s/he would have flashed red, postured and/or inked.

Having previously posted this video on Facebook, I love Will Soltau’s observation of how the octopus leaves no footprint and what a different world it would be if we humans were more like octopus in this respect.

Thank you so much for sharing Erika!

Video below added on November 25th, 2011 from You Tube – Octopus walking on land in California at the Fitzgerald Marine Reserve.

 

Challenge ‚Äď Find¬†the¬†Crab!

 

 

Typical shape of members of the kelp crab family. Species in this family are usually from 5 to 9 cm across the carapace.

This week I bring you the “Where’s Waldo?” of the marine invertebrates. There is a decorator crab in each of the images at the link below. But first, here are some clues for you.

Most of the species of crabs that decorate themselves to be masters of camouflage are in the spider crab family (Majidae family – also known as “kelp crabs”). ¬†The image to the right shows you an undecorated kelp crab with the typical long legs and distinctly shaped shell (“carapace”) of this family.

Some crabs only partially camouflage themselves, especially when they are juveniles. Others¬†“plant” so many marine neighbours onto themselves that you can’t tell them apart from their environment until they move.

Although they look like walking gardens, the organisms they attach to the stiff, curved hairs on their legs and backs are algae and animals, not plants. The animals can be soft corals, sponges or unique creatures like “bryozoans” and “hydroids”.

Not only does this covering of life allow the crabs to hide from predators, it also changes the way the crabs feel and taste. For example, sponges taste bad or are even toxic to many predators so, if you cover yourself with sponges, predators be gone! The bonus of carrying other organisms on your back is that you also have a food supply within a pincher’s reach.

It is truly astounding how well the decorator crabs match their immediate surroundings which added another mystery to my list: Is the range of decorator crabs really small so that they always match their background OR do they know to “adjust” their camouflage when they move to an area where they no longer blend in?

I have learned that the latter appears to be the case. Experiments with captive decorator crabs have shown that, if moved to a background that no longer offers camouflage, the crabs will “adjust” their decorations!

Click here to find the decorator crabs in my images or view gallery below.