Unfishy Fish

     What do you think of when someone says “fish”? The image of a salmon or goldfish probably pops into your mind. Or perhaps a colorful tropical reef fish. Odds are, you’re not thinking of a lipstick wearing, pancake shaped animal with frog feet and a long, pointy nose. You’re most likely not thinking of a Toblerone shaped shark with swirly nostrils either. The fact is, evolution doesn’t care what your idea of a fish is. It’s going to go with what’s successful and if it looks like a nightmare clown, so be it. Evolution doesn’t have a goal or a grand plan. What happens will happen and if something works, it persists.

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A generalized fish body plan.

     So here we are with and ocean of oddities to explore. To start with, let me introduce you to something that looks more or less like a ‘proper’ fish, but didn’t get the memo about how to swim like one. Enter, the razorfish (Aeoliscus strigatus). This fish is elongated and laterally compressed, giving it a razor thin appearance, hence the name. It feeds on tiny zooplankton such as brine shrimp as it hides among corals and seagrasses. Razorfish swim vertically in small schools with their snouts pointed down at all times. It is not known exactly why they do this, but it’s certainly entertaining to watch. With razorfish, it’s always a synchronized swim show. For the razorfish, the warm waters of the western Indo-Pacific are the perfect place to engage in these underwater ballets.

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A school of razorfish.

     Another weird, warm water inhabitant to be featured here is at home in the lower estuary of Derwent River in Tasmania and several other locations along the southeastern coast of Australia. Unfortunately, it is now critically endangered because of a multitude of factors including a low reproduction rate, habitat destruction, and suspected predation by an introduced sea star. The spotted handfish (Brachyonichthys hirsutus) has a sail like dorsal fin and large, webbed ‘hands’ which it uses to walk along the silty bottom. It belongs to of the order Lophiiformes, along with other strange members like deep sea anglerfishes and frogfish.

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Spotted handfish.

Unlike many other fish, which hatch out as larvae that further develops outside the egg, spotted handfish emerge as tiny, fully formed versions of their parents. Rather than floating among the plankton of the open water, these babies stick to the sandy floor and live out the rest of their lives there. The peculiar reproduction habits of this fish are exactly what make it vulnerable to the northern Pacific sea star (Asterias amurensis). Before they become fish, the eggs are attached to stalked sea squirts and other vertical organisms that are extremely appetizing to the star. As a consequence, the eggs are devoured along with the sea star’s target prey. Conservation efforts have since been set in motion to save this unique Australian animal. Along with a captive breeding program and hope of reintroduction, there has been some success with providing manmade alternatives for the handfish to lay their eggs on. Handfish have been using these sticks and as a result fewer eggs are lost to the ravenous sea star. The spotted handfish is a protected species and one of the benefits that comes with that status is efforts to reduce silt and pollution within the Derwent River estuary and restore quality to the fish’s habitat. Even though the spotted handfish is still very much at risk, there is hope for it and therefore hope for other endangered animals.

     Our next fish is not nearly as well known as some of the others on this list. It doesn’t live in warm water either and instead spends its life thousands of feet down on continental slopes where the majority of the sun’s light fails to reach. Chaunax pictus, the pink frogmouth, is another member of the anglerfish order. It can only be glimpsed from the window of a submersible or through the eyes of an ROV sent to explore the depths of the ocean. There is virtually no data about its reproductive habits, life cycle, or population trend. One study of C. pictus in the Arabian Sea observed that it only eats small shrimps. With a dearth of information like this, the most interesting thing about this fish is its appearance. Imagine a squat, pink or orange potato with a scowl to rival that of Grumpy Cat and you’re pretty much there.

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Pink frogmouth

The pink frogmouth uses its odd fins to crawl around over rocky slopes in search of prey when it’s not sitting motionless, camouflaged as a pissed off lump of cheese. The Chaunax in the video below starts walking at 1:55 if you’d like to see it in action.

     Slightly more attractive, though no more at home in shallow water, is the Caribbean roughshark (Oxynotus caribbaeus). One of the few fish on here that isn’t part of the anglerfish order, it is closely related to the more commonly seen prickly dogfish (Oxynotus bruniensis). Almost nothing is known about the natural history of the Caribbean roughshark other than that it inhabits the upper continental slope from the Gulf of Mexico to Venezuela. This shark has sloping sides and a concave belly that give it the appearance of an animal that was forced through a triangular Play-Doh mold. Its sandpapery skin is pale gray to white with dark brown patches, which actually make it quite striking.

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Caribbean roughshark.

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Swimming Toblerone

The prickly dogfish is less showy, but just as oddly shaped. The scales are raised and conical like studs making it truly deserving of its name. Like the Caribbean roughshark, it is small, only reaching a little over two feet from snout to tail. It has a mouth reminiscent of the cookie cutter shark and feeds on the eggs of other Chondrichthyans (cartilaginous fish). Prickly dogfish can be found in shallower water than roughsharks, but are also seen at great depths.

Ichthyology

Prickly dogfish.

Sharks are generally thought of as sleek and streamlined predators designed to kill, but these two species just reinforce the fact that every family has some real weirdos.

     Now we get to my personal favorite, and arguably weirdest of this group, the batfish. Despite their name, the batfishes, or Ogcocephalidae, don’t resemble bats in the least. In fact, they might be more suited to the name clownfish if that weren’t already claimed by the well known anemonefish everyone knows and loves from “Finding Nemo”. All batfishes are strange looking, but the red lipped batfish (Ogcocephalus darwini) takes the cake. With flattened body, nose-like face protrusion, and bright red lipstick looking like it was put on while drunk, this fish could be mistaken for a clown at a sorority party gone a little too far.

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Hey there, beautiful!

Also called the Galapagos batfish, it does indeed inhabit the warm, shallow waters of the Galapagos islands and nowhere else. It can be found swimming very awkwardly along reef edges over sandy substrate where its prey resides. Much of the time, it doesn’t even bother to swim. Instead, it crawls along the sand like a squashed frog and pauses frequently to lure prey.

Whereas many of its angler relatives use a nifty lure that comes out near the head region, the red-lipped batfish has one just above its lips under that pointy nose, which makes it look exactly like it has a perpetual booger hanging out of its nostril. The lure is bobbed up and down, acting as both a visual and chemical attractant for small invertebrates and a turn off for anyone else.

     Of course, it’s not this poor batfish’s fault that it looks so ridiculous. It has evolution to thank for that. For some reason, this strange body plan worked and stuck around as a result. The same goes for the rest of the fish featured in this article and so many more that it would be impossible to cover them all here. This was just a taste of the numerous odd ducks of the fish world and hopefully another motivation to keep exploring the stranger things out there. You never know what we might find next.

References:

1. Clemens, Danny. “The Red-Lipped Batfish Is Always Ready for a Night on the Town.” DSCOVRD. Discovery Channel, 07 July 2015. Web. 21 July 2016.

2. Montoya, P. Zelda, et al. “The Natural History and Husbandry of the Walking Batfishes (Lophiiformes: Ogcocephalidae).”DRUM and CROAKER: 6.

3. Schulz, Katja. “Galápagos Batfish – Ogcocephalus darwini.” Encyclopedia of Life. EOL, 2014. Web. 21 July 2016.

4. Rijnsdorp, A. D., M. Costa, and T. Munroe. “Chaunax pictus (Pink Frogmouth, Redeye).” IUCN. IUCN Red List of Threatened Species, 2015. Web. 21 July 2016.

5. Leandro, L. “Oxynotus caribbaeus (Caribbean Roughshark).” IUCN. IUCN Red List of Threatened Species, 2004. Web. 21 July 2016.

6. McGrouther, Mark. “Prickly Dogfish, Oxynotus bruniensis.” Australian Museum. Australian Museum, 2 Dec. 2013. Web. 21 July 2016.

7. McGrouther, Mark. “Spotted Handfish, Brachyonichthys Hirsutus.” Australian Museum. Australian Museum, 3 Sept. 2015. Web. 21 July 2016.

8. “Spotted Handfish (Brachyonichthys hirsutus).” Arkive.org. Wildscreen, n.d. Web. 21 July 2016.

9. Capuli, Emily Estelita. “Aeoliscus Strigatus.” FishBase. Ed. Roxanne Rei Valdestamon. Sea Around Us, n.d. Web. 21 July 2016.

Photo and Video Links:

1. http://evolution.berkeley.edu/evolibrary/article/fishtree_02

2. http://les-z-animaux.e-monsite.com/k/poissons-marins-tropicaux/autres-poissons-marins-tropicaux/poissons-lapins-et-poissons-rasoirs/poisson-rasoir-aeoliscus-strigatus.html

3. https://www.youtube.com/watch?v=PN9Rc5DrOzw

4. http://www.arkive.org/spotted-handfish/brachionichthys-hirsutus/

5. http://www.uniprot.org/taxonomy/242967

6. https://www.youtube.com/watch?v=WC69Iq8oMlo

7. http://shark-references.com/species/view/Oxynotus-caribbaeus

8. http://www.wikiwand.com/en/Oxynotus

9. https://australianmuseum.net.au/prickly-dogfish-oxynotus-bruniensis-ogilby-1893

10. http://www.natgeocreative.com/photography/1231868

11. https://www.youtube.com/watch?v=X9inncLXAHg

Ancient Treasures of Puget Sound – Bluntnose Sixgill Shark

Love them or hate them, sharks are critically important to the health of our oceans. That’s just an undeniable fact. As apex predators, they have far reaching effects that help regulate the ecosystem down to the level of organisms on which they do not even directly prey. These incredible, ancient fish have been around for many millions of years longer than any dinosaur and have remained relatively unchanged since. Currently, however, more than 60 percent of all shark species on the planet are somewhere on the spectrum of threatened to critically endangered. This is extremely wrong. Animals that have survived for so long and through so much should not be pushed to the edge of extinction by the ridiculous blunders of such a self-absorbed species. Thankfully, there has recently been a worldwide effort to protect sharks and a decline of practices like the slaughtering of sharks for their fins or livers and recreational shark fishing.

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Pictured: A cruel, wasteful, and shameful practice.

Here in Puget Sound we are very fortunate to have bluntnose sixgill sharks (Hexanchus griseus). These Sound sharks are now protected after a closure on recreational sixgill fishing was put into action by the Washington State Department of Fish and Wildlife (WDFW). This ban was in response to public outrage over the capture of several local sixgills from Elliot Bay fishing piers. The WDFW also initiated a research program with the Seattle Aquarium, the National Oceanographic and Atmospheric Association (NOAA) Fisheries Service, and other scientific partners such as the University of Washington, Point Defiance Zoo and Aquarium, and Vancouver Aquarium in an effort find more about these little known, deep water sharks.

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Thanks to efforts like these, we now have more information about sixgills, especially in Puget Sound. Sixgills, as with other deep water animals, have consistent daily patterns. They migrate down to great depths during the day and rise to shallower water at night. This is called diel vertical migration and is largest mass movement of organisms on the planet at one time. However, Puget Sound sixgills are often found in much shallower water than is typical elsewhere – sometimes as shallow as about ten feet during the day. Fortunately, this makes them easier to research. Through capture and tagging studies, it has been determined that most of the sharks in Puget Sound are sub-adults. It is suggested that Puget Sound may serve as a nursery for these animals until they have reached sexual maturity and leave to lead a more pelagic lifestyle. Not only are these sixgills young, but there is a high level of relatedness among juveniles that inhabit the same area. DNA studies found that sharks that were punch biopsied within the same set were significantly more likely to be related to each other than not. These sets consisted mostly of siblings and half siblings. From all the sharks sampled in Puget Sound during this study, analysis resulted in the identification of 33 cohorts. The stranding of a large adult female carrying 71 full-term pups in southern Puget Sound gave researchers an opportunity to look at relatedness within a litter, and confirmed the suspicion that females are polyandrous, that is, mating with more than one male during a breeding season. Six male sharks contributed to the genetics of this litter, but the contribution was unequal because only a few of them contributed the majority of the genotypes found.

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This neo-natal pup shows the green eyes and long upper portion of the caudal fin that are characteristic features of sixgill sharks.

Litters can range from 22 to 108 pups and gestation is hypothesized to be no less than 12 months and quite likely closer to 24 months or more. During breeding, male sharks appear to nip at the female’s gill area to get her attention and to entice her to mate as evidenced by white marks observed by biologist divers only during this time of the year. Similar behavior is seen in other shark species. Female sixgills mature at around 14 feet and males at closer to 10. As with many sharks, sixgills seem to grow slowly, but not a lot is known about age at maturity or rate of growth. One shark was found to double in size over its first year of life and then was recaptured later appearing to have grown around a third of an inch per month since. This is just one individual, however, and a much larger sample across different populations would be needed to fully understand sixgill growth rate.

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At full size, the biggest sixgills can grow to a little over 15 feet, making this shark the largest fish in Puget Sound and one of the largest living sharks in the world. As their name suggests, they have six gill slits behind the head rather than the usual five found in most sharks. Their snouts are large and rounded, hence bluntnose, and protrude in front of jaws containing very unique teeth. The upper jaw has rows of thin, hook-like teeth that are common in many shark species. However, the lower jaw contains teeth that differ highly from those of other sharks. These teeth from rows of six on either side of the jaw and are deeply serrated like saw blades. Teeth like this are very similar to those seen in Jurassic sharks, suggesting that this species is quite ancient and primitive. Since these animals normally spend their time in very deep water (up to over 8,000 feet down – to put this in perspective, a mile is 5,280 feet) where food is scarce, they take every opportunity to scavenge when they can. Having saw like teeth on the lower jaw and puncturing teeth on the top jaw help them hold and saw through large chunks of flesh such as whale blubber. This allows them to remove more manageable pieces from huge carcasses, which they then swallow whole.

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Illustration of upper and lower teeth

Not only are sixgills adaptable, deep sea scavengers, they are also skilled predators. These fish are capable of surprisingly great bursts of speed that contrasts with their sluggish appearance and behavior. Prey can include anything from crabs, mollusks, and teleosts (bony fish) to other cartilaginous fish or even marine mammals. Despite this, there has never been a serious injury or fatality recorded as a result of interaction with a sixgill shark. On the contrary, people often go on dives in Puget Sound specifically to see them. Sixgills do not appear to fear humans and show inquisitive behavior when they encounter one. If a person gets too close for the animal’s comfort, it will calmly swim away. Touching a sixgill may cause it to whip around and nip at the diver in warning, but no injuries usually occur and those that do are minor. Still, sixgill sharks are very big and powerful animals that should always be treated with caution. Even biologists who study sixgill behavior and are very knowledgeable will conduct their research from the safety of a shark cage or a boat and give the sharks their space when diving with them.

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For the research that has been done on bluntnose sixgill sharks, we have barely touched the surface when it comes to understanding their lives and the ecological roles they play. What we do know gives us even more incentive to protect and study these amazing creatures. If Puget Sound is in fact a nursery for pups and young adult sharks, then it is a valuable resource for maintaining the genetic diversity of this species. Many shark species suffer from low genetic diversity caused by human actions and the fact that they reproduce slowly. Puget Sound sixgills, even with the relatively high number of related individuals, still shows moderate genetic diversity. Preserving safe and productive areas like Puget Sound is crucial to the survival of shark species worldwide. Sharks are excellent indicators of environmental health and where they do well, other species will undoubtedly thrive as well. Helping sharks like Puget Sound sixgills helps improve our planet’s oceans little by little, and in turn, our lives.

References:
1. Martin, R. Aidan.  “Swimming with Jurassic Sharks.” ReefQuest Centre for Shark Research (2003). http://www.elasmo-research.org/education/topics/d_jurassic_shark.htm

2. Larson, Shawn, et al. “Relatedness and polyandry of sixgill sharks, Hexanchus griseus, in an urban estuary.” Conservation Genetics 12.3 (2011): 679-690.

3. Ebert, David A. “Biological aspects of the sixgill shark, Hexanchus griseus.” Copeia (1986): 131-135.

4. Andrews, Kelly S., et al. “Diel activity patterns of sixgill sharks, Hexanchus griseus: the ups and downs of an apex predator.” Animal Behaviour 78.2 (2009): 525-536.

5. Andrews, K. S., et al. “Acoustic monitoring of sixgill shark movements in Puget Sound: evidence for localized movement.” Canadian Journal of Zoology 85.11 (2007): 1136-1143.

6. Rupp, J. “A natural history of the sixgill shark, Hexanchus griseus.” Proc Puget Sound Res (2001).

7. Bauml, J. “Hexanchus griseus.” Animal Diversity Web (2004). Web. 11 Feb. 2016 http://animaldiversity.org/accounts/Hexanchus_griseus/

Photo and Video Links:
1. https://www.bostonglobe.com/metro/2014/07/23/massachusetts-ban-shark-fin-trade/S1eoogIdZ8W9UbqalQguQO/story.html

2. http://shark-references.com/species/view/Hexanchus-griseus

3.http://wdfw.wa.gov/fishing/bottomfish/identification/sharks_skates_ratfish/h_griseus.html

4. http://www.arkive.org/bluntnose-six-gill-shark/hexanchus-griseus/

5. http://cookislands.bishopmuseum.org/showImage.asp?file=MM/MX5/5BB029_Hexa-gris_2FAO_zzMX.JPG&title=Hexanchus+griseus++%28Bluntnose+Sixgill+Shark%29&height=400&width=600

6. http://www.seattleaquarium.org/sixgill-sharks

7. https://www.youtube.com/watch?v=P4cAlgiX59I

Are You Afraid of the Dark? – Horrors of the Deep Ocean

The deep sea has been less explored by humans than the surface of the moon! Down there in the depths, under bone crushing pressures, live some of the most alien things you could possibly imagine. Here are a few of the many fascinating residents of this barely touched world:

Deep Sea Hatchetfish
This silvery little fish, whose face looks like it’s seemingly frozen in a silent scream, resides in most of the world’s oceans at depths of up to 4,950 feet. Their huge, tube shaped eyes allow them to catch the very little light that manages to reach even the shallower waters of their range. That way, they can see prey and watch out for predators. They also have a special defense mechanism that allows them to hide when nearer the surface. Special bioluminescent photophores, or light producing organs, will mimic the light of the surface waters to create the illusion of the fish’s disappearance. This is called counterillumination. As one of the main food sources for other creatures in the deep, it’s a handy trick to avoid being eaten.

Stoplight Loosejaw
The stoplight loosejaw is a small species of dragonfish found below the depth of 1,640 feet. They too have light producing photophores, which is where they get their name. The largest one emits red light while the smaller one emits green. Red wavelengths from sunlight don’t reach that far down, so the color red is essentially invisible to most creatures, which is a reason why many of them have red bodies. The stoplight loosejaw, however, is one of the few that can actually emit its own red light and detect those wavelengths. This enables it to use those photophores as floodlights to spot prey. The “loosejaw” part of their name refers to the minimal attachment of the lower jaw to the upper portion of the skull. They have no floor to the lower jaw at all and it is only connected by small hinges. This reduces water resistance so they can snap their jaws shut more quickly when they find something edible.

Deep Sea Anglerfish
Deep sea anglerfish is a term for many fish in the family Ceratiidae. This is possibly one of the better known deep water fish because of its fearsome appearance. They all share the trait of using a lure to attract prey to them since they aren’t the fastest swimmers in the ocean. This tactic also conserves the precious energy that is hard to come by, as there is little food down where they live. All they have to do is wait and then pounce. Some have light producing bacteria in their lures that makes them even more attractive to potential meals. That’s cool and all, but the weirdest thing about these species is their sexual dimorphism (morphological differences between sexes). The fish we are all familiar with are only the females. The male is actually only a few millimeters long and permanently fuses to the female’s body as a parasite when the two meet. His only purpose is to provide genetic material to the female. As breeding opportunities are so rare down there, this is a clever, albeit creepy, evolutionary adaptation. Once the female finds a mate, she’ll never be lonely again.

Sleep tight!

References:
1. Cronin, Thomas W. “Camouflage via Emitted Light – Counterillumination.” Visual Ecology. N.p.: Princeton UP, 2014. 315-19. Print.

2. Kenaley, Christopher P. “Revision of the stoplight loosejaw genus Malacosteus (Teleostei: Stomiidae: Malacosteinae), with description of a new species from the temperate southern hemisphere and Indian Ocean.” Copeia 2007.4 (2007): 886-900.

3. Pietsch, Theodore W. “Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes).” Ichthyological Research 52.3 (2005): 207-236.

Photo Links:
1. https://creaturefacts.files.wordpress.com/2015/04/ed76a-hatchetfish_face_killah.jpg

2. http://upload.wikimedia.org/wikipedia/commons/a/ae/Alacosteus_niger.jpg

3. http://www.frogfish.ch/image/tiefsee-angler/0-ceratioid-montage-1-1.500a.jpg