The Porbeagle Shark, Lamna nasus

Courtesy University of Denver

The Porbeagle (Lamna nasus) appears to be, at first glance, the very stereotype of the shark.  Its streamlined body and strong jaw give it away as a fast and efficient predator.  But there is more to this shark then one would expect.  In fact, it can even be described as adorable.

Other than the vaguely smile like appearance of the mouth, you might be asking yourself what one could find cute about this shark.  The reason can be found in their behavior.  Porbeagles have become well known for actions that can be described only as playing.  Young sharks have been seen rolling around in kelp until they are covered in it and then speed off, while other Porbeagles will then give chase trying to grab bits of the kept off, but never harming the entangled shark.  Soon, another shark will start rolling around until tangled as well and the group then begins chasing this individual.

Some originally thought that the sharks were trying to find small prey items hidden within the kelp, but they were never observed eating anything.  Others suggested that the action was done to remove parasites, but this idea was also shown to be lacking.  The only explanation that has been provided that makes any sense is that the behavior is done for play.


Another play like behavior can be seen when these sharks come across a floating object.  They will grab at the object in a way that goes beyond mere investigation and will even go so far as to throw their 'toy' out of the water repeatedly.  The idea that it is more then just curiosity at a novel object can be seen when multiple Porbeagles gather around a single object.  They will each attempt to play with it and have even been seen passing the object from one to another!

The leading hypothesis as to why Porbeagles engage in play is related to why most other organisms are thought to play.  It is a learning process, helping to develop and maintain their hunting techniques.  If this is accurate, then such playfulness likely gave these sharks an evolutionary advantage over those species that never developed this unusual behavior.

Porbeagles can be either solitary or gregarious, especially in the case of juveniles, but adults have been witnessed in groups for reasons other than mating as well.  Though these groups are often transitory.

They primarily reside in colder waters though the females will migrate to warmer climates to birth their pups.  To combat the cold, they are able to thermoregulate, making them endothermic.  They conserve heat produced by their muscles through a series of specialized blood vessels known as the retia mirabilia, or wonderful net.  This allows them to maintain an active lifestyle despite living primarily in cold waters.  Their ability to raise their body temperate is among the best of all sharks, second only to its close relative the Salmon Shark (Lamna ditropis).


A member of the order Lamniformes, the Mackerel Sharks, they are closely related to other more well known fast swimming predatory sharks such as the Great White and the Makos.  The Porbeagle is, like its relatives, aplacental viviparous, which means that the eggs are internally fertilized and the young will hatch before being fully developed and continue their gestation internally.  The Porbeagle also displays what is known as oophagy.  When the pups, still within the uterus, have exhausted their yolk supply, the female will begin to release unfertilized, yolk rich eggs that the young can feed on.  Once fully developed, the female Porbeagle can give birth to, on average, a litter of four, two from each uterus.

These sharks are harmless to humans with only three attacks being recorded.  One was a provoked non-lethal attack on a person, the other two were on boats.  Considering that they are common game fish, this is not surprising.  In fact, the over fishing of these sharks has led to them being listed as vulnerable.



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Regalecus glesne, the Giant Oarfish

A washed up Giant Oarfish found in 1996 by members of the U.S. Navy.

Regalecus glesne, or more commonly known as the Giant Oarfish or the King Of Herrings, is quite possibly the longest living fish and certainly the longest living bony-fish.  The debate stems from the fact that the first Giant Oarfish to be encountered was a specimen that had washed up in Scotland in 1808.  The individual was recorded to have a length of 56 ft (17 m).  However, other than this single instance, the largest specimen encountered was only 36 ft (11m).  This has led some to claim that the first recording was in error while others do not find it surprising and believe that individuals of 50 ft (15.24 ft) in the wild may not be uncommon.  But until further data can be found, the limit of 36 ft is the most often cited.

This disagreement as to the limit in size for the Giant Oarfish puts it as either the longest fish period or simply the longest bony-fish.  To compare its size, the Whale Shark (Rhincodon typus), generally considered to be the largest living fish, has a maximum recorded size of 41.50 ft (12.65 m).

Despite being an enormous fish and having a range throughout the worlds tropical and temperate oceans, the fish is rarely sighted.  The few times it has been encountered have almost exclusively been when specimens have washed ashore or into shallow water, either dead or dying.  Though a few instances of live individuals being encountered in the wild have occurred.  Though no matter the state of the fish, encounters are sure to grab regional, if not worldwide attention.

A taxidermied Giant Oarfish in the Museum of Natural History of Vienna.

The Giant Oarfish's natural habitat is at a depth of between 600 feet (200 m) and 3,000 feet (1,000 m), though healthy individuals have been occasionally known to rise to the surface for short periods for unknown reasons.  It is during these rare excursions to the oceans surface, or when they have washed ashore or into shallow water, that it is thought that these unusual fish gave rise to the myth of the sea serpent.  While ill, it is not uncommon for individuals to swim with their heads and the crests of their dorsal fins to be sticking out in a way that resembles elaborate spines or horns.  In fact, it is one can still find the occasional old map with images of sea monsters that curiously resemble Oarfish.

It is not hard to see how sightings of this fish could give rise to myths of sea serpents.

The most notable feature of the Giant Oarfish is its long and laterally compressed body.  Despite having an immense length, they have a lateral length of only around and inch or two.  They also have pinkish to crimson red fins.  The most obviously being the body length dorsal fin with its large crests and its long, thin pelvic fins.  In fact, other then these and the small pectoral fins, these fish have lost all of their other fins.  They also have a highly extendable sideways mouth, much like those found in certain flatfish such as flounder.  There body is a brilliantly shiny silver with blue to brown spots and stripes, however these spots and stripes will often fade as the fish grows ill.  However the fish's shiny exterior will remain.  The reason for this shininess is not due to scales, for they utterly lack any.  Instead, they have large amounts of Guanine embedded within their skin (the same molecule that is used in DNA) that gives them their metallic luster.

Like many of the largest organisms in the worlds oceans, all Oarfish and their closely related cousins, the Ribbonfish and the Crestfish, feed on some of the smallest of organisms.  Feeding primarily on the zooplankton where they selectively strain out their preferred foods, such as tiny euphausiids (krill), shrimp and other crustaceans.  They have also been known to occasionally eat smaller squid, fish and sea jellies.  Using their highly extendable mouths, they feed in a fashion similar to many other fish, by extending their mouth and sucking in their prey.  Their food is then ingested whole.

The source of the common names for the Giant Oarfish come from the fact that people once believed the fish swam by undulating its body while using its long pelvic fins to 'row' through the water.  This, however, is simply a myth.  It moves by undulating its long dorsal fin while keeping its body perfectly straight, in what is known as amiiform locomotion.  Its other common name, the King Of Herrings, comes from yet another myth.  This one being traced back to fishermen occasionally seeing the Giant Oarfish around the same time as they were catching Herring and them assuming that the fish was leading the school.  With the rather regal look of the Giant Oarfish, it is not hard to see why this was so.  In fact, this myth gave rise to its genus name, as Regalecus means regal.


In the wild, the fish swim vertacally through the water column, with their tail end facing down and their head pointing straight up.  It is believed this may be so that the fish can spot the silhouettes of its prey against the light from the surface, much like many other species of deep water fish are known to do.


The Giant Oarfish is known to be a migratory species.  Specifically, they are what is known as oceanodromous, meaning that their migrations never take them out of sea water.  They migrate to waters off of Mexico between July and December to spawn, then back to their original locations throughout the worlds oceans.  The fish are strict loners so males and females will release their gametes into the water to be fertilized as part of the plankton.  The eggs are brightly colored and buoyant, floating to the surface where they are fertilized and hatch after about three weeks into a larval form that stays near the surface, feeding upon the zooplankton that they live amongst.  These larva are so morphologically distinct that their identity was long a mystery until more developed specimens were found and the link to adult Oarfish was made.

The larval form of the Giant Oarfish.

A slightly more mature individual.

A healthy Giant Oarfish has been caught on camera at its normal depth only once.  The video was taken by an ROV (Remotely Operated Vehicle) at a depth of 2509 ft (765 m) in the Gulf Of Mexico near a deep-sea oil rig.  I have included the video of this amazing event for your viewing pleasure.

 


The Giant Oarfish is truly a marvelous fish that brings a sense of wonder for scientists and the public alike whenever it is encountered.  It is a prime example of how evolution can take life in truly fantastical directions.

Mola mola, the Ocean Sunfish

The Ocean Sunfish is a bony fish that has made it its life-long goal to set as many records as possible. It does this while having an appearance that is, in a word, odd. These fish have undergone so many specializations as to set them apart from nearly every other group of extant fish.

The largest species, the Ocean Sunfish Mola mola belongs to the genus Mola of which it shares with only one other living member, The Southern Sunfish Mola ramsayi. In turn, the genus Mola belongs to the family Molidae which contains three genera and five known species. Until more genera were uncovered, the genus Mola did not exist and was instead classified under the same genus that houses the pufferfish, Tetradon. However, with better study of these fish and improved classifications of the related genera and species, they were moved to their own family and genera. Though they are still classifed within the same order as the pufferfish, porcupinefish, boxfish and filefish, the Tetradontiforms.

The Sunfish's relation to the Tetradontiforms has led to an ongoing debate as to the toxicity of these fish. Some claim that the organs contain a low level tetrodotoxin, the same kind of toxin found within certain pufferfish (as well as the Blue-Ringed Octopus and certain newts) and the cause of Fugu poisoning. Despite the claims, there have been no confirmed cases of tetrodotoxin poisoning in any species of sunfish. Which is certainly reassuring for the multiple cultures (primarily Japanese and Thai) that find sunfish flesh to be a delicacy.

Seen next to a diver, the adult Ocean Sunfish's size can truly be appreciated.

These fish have an appearance that makes them seem like they are only half a fish. In a sense, they are as their cauldal fin (the tail fin) has degenerated to a clavus which barely has any use in locomotion, acting more as a stumpy rudder. The dorsal and anal fins have become the prime sources of locomotion, moving side to side to slowly propel the fish through the water with a speed of under 2 mph (3.2 hm/h) and a range of around 16 miles per day (26 km). In fact it is due to this slow speed and large size, combined with their habit to lay on the surface of the water on their side to sunbathe that they have become known as a boating hazard where they have damaged hulls and destroyed engines. But this is essentially the only threat these docile fish pose, with the lone example of direct injury occurring when of boy was injured when an Ocean Sunfish breached (jumped out of the water) and landed on his boat, knocking him into the water.

One of the first record breaking traits to be noted about the Ocean Sunfish is its size. These fish are both the heaviest bony fish as well as the largest ray-finned bony fish. With a weight of up to and sometimes exceeding 2,200 lbs (1,000 kg), these fish are massive. Also, due to their odd appearance, they often have a length equal to their height, often around 11 ft. (3.3 m).

Despite their large size, Ocean Sunfish feed primarily on small organisms.  Their primarily source of nutrition are sea jellies, but they have also been known to feed on small fish, crustaceans, squid and eel grass.  Their teeth have fused into a beak, similar to many other tetradontiforms, but the sunfish's has fused in a way to prevent it from closing its mouth fully.  So instead of biting at its food, it will suck it in where it will blow water back and forth rapidly to tear apart its soft bodied prey.  It will then partially swallow its food and allow its pharyngeal teeth to grind the food down to a more manageable size before swallowing it the rest of the way.  The pharyngeal jaw is a trait held in common by some 30,000 species of fish and is, as the name suggests, teeth or, in some rare cases like Moray Eels, fully mobile jaws used to pull food down the throat.  In the Ocean Sunfish, they are basic teeth in the pharynx that simply grinds bits of food and nothing more.  Due to their nutrient poor diet, the Ocean Sunfish must eat frequently.

Due to the primary prey item of the sunfish being sea jellies, these fish are often found dead after they have tried to eat a plastic bag floating in the water and are unable to swallow it further.  Making pollution, as well as ocean traffic and fishing the primary threats to these fish.  Due to their size, they have few natural predators.  The only ones of note being Sea Lions, Orcas and certain sharks.

One of the other record setting traits of these fish can be found in their rate of reproduction.  The Ocean Sunfish lays more eggs at a time then any other vertebrate.  At a time, a single female sunfish can lay as many as 300,000,000 eggs (yes, that is 300 million).  These eggs are then externally fertilized by a male and then left to drift with the rest of the plankton on the oceans currents.  These eggs are fed on by multiple organisms all along the food chain including fish such as tuna.  It is because of this rather wasteful method of reproduction that such a large number of eggs must be produced to maintain the species population.  Once the eggs have hatched, the tiny fry appear as 1 mm, spiny spheres, betraying their common ancestor with the pufferfish.

A newly hatched sunfish fry.

Another of the record setting traits of the Ocean Sunfish has to do with the size of its spinal cord.  Due to the shortening of the body that has occurred over time, the actual spinal cord only extends about 1mm from the base of the brain.  The rest of the body is connected through the peripheral nervous system.  Thus, the sunfish has the smallest spinal cord of any fish in relation to their body.  They have also lost many of their vertebrae leaving them with the fewest of any fish.  In fact, despite being a bony fish, the sunfish has lost nearly all of its bone, replacing it with cartilage.  This adaptation has allowed the sunfish to grow to such large sizes without causing damage to its skeleton.  Further showing convergent evolutionary traits with the cartilaginous fishes is the development of denticles, sharp, teeth like protrusions of the skin.  These give sharks and rays, as well as the Ocean Sunfish, their sandpaper like texture.  This acts as a kind of body armor as well as decreasing water friction allowing them to move more easily through the water.

Class Holothuroidea, the Sea Cucumbers

The sea cucumber Bohadschia argus

Echinoderms, in general, are an often overlooked group of creatures.  Other than for being ubiquitous members of tidal pools and the ocean floor, your average person knows little about them.  One class in particular, Holothuroidea, is generally seen as just a curiosity despite having a series of downright bizarre traits and behaviors.  Commonly known as the Sea Cucumbers due to their cylindrical appearance, these scavengers can be found in every ocean.  Not only are they indigenous to all oceans, many species travel in herds that can reach numbers well over a thousand.

Like other living echinoderms such as sea stars, urchins, brittle stars and crinoids, sea cucumbers posses what is known as pentaradial symmetry.  This means that their body plan can be split into five equal sides.  At first sea cucumbers seem to break this rule, but that is only when looked at from above.  When observed on end, the pentaradial symmetry is easily distinguishable.  What appears to be bilateral symmetry at first glance is an intriguing illusion when you take into consideration that all echinoderms evolved from a common ancestor that possessed bilateral symmetry, a feature that is only shown in modern day larval forms. 

Your average sea cucumber feeds by sucking up ocean sediment like a living vacuum cleaner.  Using feeding tentacles, they pick through the sediment and the remaining substrate is passed out the opposite end.  A few species will go so far as to extend their feeding tentacles to pick pieces of food out of the passing current they position themselves near.  There is also one species that gains its nourishment through a commensal relationship with deep-sea angler fish, though little is known about this relationship. They generally propel themselves along on 8-30 small tube feet that make use of echinoderms trademark water vascular system which is essentially a body wide hydraulic system.  One subclass, Apodacea, has gone so far as to completely lose their tube feet and instead burrows through sediment with a series of muscular contractions along their body.

All sea cucumbers have an endoskeleton, but in most, it has become greatly reduced to little more than small ossicles sparsely numbered throughout the mesoderm.  A few species have adopted hardened calciferous plates covering their body for protection, but it is not common.  This leaves most sea cucumbers with a rather soft texture that makes one wonder what sort of cucumbers the person was eating who granted these creatures their common name.  Many sea cucumbers make perfect use of their squishy bodies when it comes to getting into tight spaces.  Their body tissues contain a modified form of collagen known as catch collagen.  In most animals, this provides tissues with a flexible, but strong nature by forming a network of interconnected proteins.  Sea cucumbers have modified this protein so that they can become viscous at will allowing them to literally pour their tissues through a tight crevice.  Once in, they can let their catch collagen reconnect, reforming their tissues into the orderly form it once was.

As if turning themselves to liquid wasn’t odd enough, members of the order Aspidochirotida have a somewhat…unsettling defense mechanism.  They turn their anus at an attacker and through a tear between the coelom (body cavity) and cloaca (the common opening for the intestinal, urinary and reproductive tracts), they expel their respiratory tree which is coated in toxins and a sticky material.  This process, known as evisceration, ensnaring the would be predator in what one can only compare to the most nauseating imitation of Spider-Man ever.

One would think having the ability to spew toxic innards out of one’s ass would keep any sane creature away, but one peculiar fish is not detered.  Known as the pearlfish, many members of the family Carapidae make their home within the confines of the sea cucumber’s cloaca.  These slender fish often cause no harm or benefit to their host and simply use the space to remain hidden within.  A few species have been known to…ahem…eat out the sea cucumber, but this behavior is rare.  A few members of pearlfish have found their home so comfy they invite in their mate.  In a disturbing twist, the pearlfish uses the reproductive space of the sea cumber as its own love abode.

For the most part, sea cucumbers possess few traits useful to humans, though the flesh of some species is eaten in certain oriental cuisine.   Sea cucumbers have also been a staple of traditional Chinese medicine for generations, though the effectiveness is debatable.  A study single has suggested that the fatty acids found in sea cucumber tissue could play a role in tissue repair, but the actual use was never tested.  Another study found an extract could be useful for internal pain when studied on mice, but there was no effect when applied for external pain leaving the validity of the study in doubt.  Finally, a recent study concluded that the Lectin protein (used in the binding of sugar) found in the species Cucumaria echinata actually inhibited the growth of the Malaria parasite.

Most sea cucumbers are dioecious, meaning they have separate male and female sexes.  A few species are protandric, which allows members of one sex transform themselves over to the other sex at one or more points in their life.  The average life cycle involves mass spawning into the current with the ensuing zygote and eventual larvae joining the planktonic drift.  About 30 species, however, fertilize internally.  Once the egg hatches, a feeding tentacle grabs the larva and moves it into a brood pouch for development.  Here they grow to maturity and either crawl out from where they entered or make a rupture out the back end near the anus.  This explosive birth is not fatal to the adult who possesses astonishing regenerative capabilities (after all, if they can re-grow their ‘lungs’ a hernia should pose few problems).

This article was written at the request of one of my readers over at Mad Mikes America.  Anyone who would have a request for an article, feel free to either leave the request in the comments section.  Thank you Morgan Williams for your request!

Symbion pandora

Today, over at Carl Zimmer's blog, The Loom, he posted a video created by CreatureCast. CreatureCast is a site devoted to spreading information on various critters and concepts in Biology. Often, the organisms mentioned are a bit on the odd side, so you know I absolutely love it.

In this instance, the organism featured is Symbion pandora, an odd little critter that lives solely on the mouth-parts of the Norway Lobster (Nephrops norvegicus). They were discovered only in 1995 and were so unique they had to be given their own phylum, Cycliophora. Between then and now, two other species have been discovered, all three of which are within the same genus and all having similar life cycles.

Symbion pandora, and its two relatives, are commensal symbiotes with their lobstery homes. This means that they benefit from the relationship while the lobster is unaffected. These creatures simply live on the mouth-parts and filter bits of food and not much else. They have no known predators (other than those who feed on their host lobster) and have only one real worry, the lobster's molting process. It is during this time that the more complex of Symbion pandora's two modes of reproduction comes into play. At this point, I shall let the creative minds behind CreatureCast take over and explain to you this rather interesting process.

The Curiously Complex Lifecycle of Symbion Pandora from Casey Dunn on Vimeo.

Callorhincidae, the Plough-Nose Chimaeras

A juvenile Callorhinchus milii.

Callorhincidae is a family of Chimaeriforms more commonly known as Plough-Nose Chiaeras, the Elephant Sharks and even occasionally the Ghost Shark (a name which is frowned upon outside of colloquial use as this term is generally used to describe the closely related family Chimaeridea). While all Chimaeriforms are known to be a bit odd in appearance, members of this family of deep water fish have taken things just a step further. As their common name sake suggests, they have evolved a unique proboscis (known as a rostrum) that functions much like a metal detector. But in this case, the bits of treasure it is seeking are hidden morsals of food buryed within the sea floor.

The Chimaeras, are among the oldest group of living fish with known fossils dating back as early as the Devonian. A member of the class Chondrichthyes (the cartilaginous fish) and sub-class Holocephali (of which the order Chimaeriformes is the only extant order), the family Callorhincidae contains only one genus, Callorhinchus which in turn is composed of three known species: Callorhinchus callorynchus, Callorhinchus capensis and Callorhinchus milii.

These fish are often found around 200-500 meters (656-1640 ft), although they have been known to come into shallower water to lay their eggs. They range in size from 90 cm to 125 cm (3 to 4.10 ft). But as I have said, their most prominent feature is their rostrum that is filled with sensory nerves. It functions much like the broadened head of the various species of hammerhead sharks by detecting the electrical signals given off by other organisms. With this tool, the Plough-Nose can simply swim along the sea floor until its 'nose' picks up the faint signals of previously hidden critters.

A close up of the sensitive rostrum of the Plough-Nose Chimera.

While the unique nose of this fish has granted them an easy way to find a meal, it has also attracted many deep sea fishers who are hoping for a unique catch and for its flesh (which supposedly, has a taste simimilar to Cod and has become quite popular in many restaurants in Australia and New Zealand). Though unwary fishers and researchers may encounter a defensive feature shared by all extant Chimaeriforms, a spine at that base of the dorsal fin. Thankfully this family does not seem to be threatened by such human actions.

Another odd feature about the Plough-Nose and other Chimaeriforms can be found in their reproduction. They share many features with their closest relatives, the sharks and rays, internal fertilization and the laying of protected eggs known as 'mermaid purses' (though some sharks are viviparous). However, the Chimaeriforms method of fertilization differs greatly. While male sharks and rays have a pair of claspers located near the pelvic fin, Chimaeriforms have a pair of split claspers as well as a retractable structure on its forehead. Known as the tentaculum, this structure is a spiny knob like protrusion that is believed to be used to 'stimulate' the female during mating. There is an obvious joke here, but it is far to blatant to mention.

A final interesting feature about these fish has been revealed by the Elephant Shark Genome Project. The project was proposed due to the fact that Chimaeriforms have the smallest genome of any cartilaginous fish and because cartilainous fish are the oldest jawed vertebrates. Using the Australian Ghost Shark (Callorhinchus milii, the project hopes to be able to use these fish as a model which could help shed light on vertebrate evolution. One unexpected result of the inital findings is that this species has a three cone color vision system, something shared by humans.

Malacosteus niger, the Black Dragonfish

Malacosteus niger is a member of a group of deep water fish known as Dragonfish or Loose-jaws. More commonly known as the Black Dragonfish, this denizen of the deep has stumbled upon an evolutionary cheat code. It has stealth vision.

Most organisms in the deep oceans can only see blue to green light. The reason for this is due to the light absorbing traits of water. By the time any water gets down to where this critter lives (915 to 1,830 m or 3,000 to 6,000 ft), all the red, yellow, orange, and other colors have been absorbed. This is why most bioluminescence is blueish. But the Black Dragonfish is a non-conformist and is not willing to settle with just blue. Instead the Dragonfish relies on a pair of photophores under its eyes that emit red light. With only it and a handful of other species being able to see such wavelengths of light, the Dragonfish can effectively use its photophores as targeting sensors. The red light will shine on its prey and the morsel won't even know that it has been sighted.

To emit red light, the Dragonfish has modified one of its many blue photophores. Using pigments and filters, the light is eventually modified until it is emitted at the proper wavelength of 705 nm, the far red. While this is certainly an interesting adaptation, it is nothing compared to how it actually sees the red light it emits.

Some organisms, such as the closely related genus Aristostomias, just have an extra photoreceptor pigment. But such a simple adaptation that would have been too easy for Malacosteus niger. Instead it makes its own photoreceptor. One of the many things eaten by Dragonfish are copepods. Copepods, in turn, often feed on photosynthetic bacteria. This gives the Dragonfish just the right materials to start fashioning itself spy lenses. Some of the chlorophyll from the bacteria makes its way to the eye where it settles on a photoreceptor. Here, it can absorb the rare red light and transfer the signal to the photoreceptor cells.

This was such a brilliant idea that the idea is now being experimented upon for human use. In experiments involving rabbits and mice, after being given eye-drops with the chlorophyll derivative chlorin e6, the rodents were able to see twice as well in the dark. In timer perhaps such an enhancement may be available to people.

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References:
Discover
The Bioluminescence Webpage

Support mounting to ban shark finning.

Being someone who grew up wanting to be a marine biologist, this is a subject that has always enraged me. While only recently getting the attention it deserves, shark finning has been one of the most destructive of practices effecting the oceans.

For those who have not heard of this, shark finning is the process of shark fishing purely for their fins. Often the captured sharks are brought aboard, their fins are cut off and the bodies (many times still alive) are thrown back into the waters as waste. These sharks either bleed to death or drown (as most species of sharks caught must remain motile to respire). This is all done because of its demand for the traditional Chinese 'delicacy' Shark Fin Soup.

It is estimated that 73 million sharks are finned annually. However the total number of sharks harvested for their fins in total may reach up to 100 million. This has lead to a wide variety of species of sharks to be listed as threatened or endangered with many more species out there that should be listed but aren't for either lack of data or pressure from fishing groups. In the past 15 years alone, the North Atlantic shark population has dropped by 50%.

As any ecologist knows, destroy the predators and you destroy the ecosystem. Without sharks, the entire ocean biome will collapse. With whole oceanic ecosystems verging on collapse as it is from this and other fishing practices, something must be done now.

Thankfully there has been growing awareness of the situation. Groups like Shark Savers and Stop Shark Finning have been working tirelessly to end this pointless and brutal practice. Currently in the US a bill to ban the trade of shark fins is being considered in California. If this bill passes, it would join Hawaii, Oregon, Washington and Guam in banning the practice in the US.

There have been some who say that to ban something that is inherently Chinese is a form of racism. To these people I have little but disdain. To claim that the destruction of the Earth is fine as long as it is in the name of tradition is so utterly wrong as to be almost not worth discussing. Anyone who cannot see this is either being deceitful or is blatantly moronic.

With more people starting to understand and take interest in sharks, it is my hope that perhaps this vile practice may be laid to rest. Seen by future generations as nothing more than a disgusting piece of human history.

Sacculina carcini

Succulina carcini starts life as a harmless little critter who lives a care-free life exploring the busy world of the planktonic drifts. Its larvae look like something H. R. Geiger would have created if he went through a cute phase.

Who’s an adorable little Cthulian horror?

But just like any spawn of an Elder-God, there comes a time when they just want to settle down. So the females search for the perfect home to eventually raise their own brood of Lovecraftian abominations. But not any home will do, no, the females are very picky about where they make settle. In this case it is an unsuspecting crab.

Hello mister crab! Doesn’t he look happy?

It is now that Succulina swims underneath our happy little crab there and using a needle on the rear of its body injects a cluster of cells into the crab and simply discards with the remaining 90% of its body. As if this were not disturbing enough, the protoplasmic blob that is left over begins growing tendrils throughout the body, including the brain and around the eye stalks. It uses these nightmarish appendages to leach nutrients from our once happy crab. Eventually a cancerous blob begins to grow on the underside of our once care-free crab. Known as the externa, this is the egg sack of our once terrifying yet oddly cute free-swimming friend.

Holy Hell! What did you do to Mister Crab?!

But the cancerous abomination and internal leech tentacles are not the worst part. Yes, it really can get worse. Remember when I said they grow all the way to the brain? Well there is a very specific reason for this. This is because it needs to take over the mind of its unwitting host. It stops the crab from molting (as this would cause it to shed the externa) and just grow and grow. It changes its habits so all it does is eat and carefully groom the cancer pouring out of its carapace like it is its own egg sack. It doesn’t even matter if it was a female crab that was infected either. Sacculina will just change the hormone levels of a male crab so that its underside grows wider like a female (all the better for the externa to grow). It also effectively sterilizes the crab so that it never has any interest in any other crab. It just eats and grooms the progeny of The Blob. When the eggs are finally ready to hatch, Sacculina takes further control of the crab, forcing it to walk into shallow water and shake open the externa so that all the little larvae may swim free in a horrifying imitation of the crab’s own ritual of releasing its eggs. This completes Sacculina’s life cycle with thousands of tiny larvae off to find crabs of their own to infect. And just to make matters just a tiny bit worse, Sacculina is actually just a specialized form of barnacle. Try looking at those ubiquitous shore side critters again.

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References:
Zimmer, Carl. Parasite Rex

Phlyctenactis tuberculosa, the Wandering or Swimming anemone

Phlyctenactis tuberculosa is a common yet unique anemone that goes by many names The most common being the wandering anemone or swimming anemone. They are also known as brain anemones, beach ball anemones, baked beans anemones, or Thenaria. Native to waters off of Australia and New Zealand, often growing to a size of 15 cm, making this New Zealand's largest anemone species.

Phlyctenactis tuberculosa is primarily nocturnal, being found attached to rocks or kelp during the day. To protect themselves, they are covered in vesicles which are filled with nematocysts (stinging cells). The arrangement of these vesicles give the wandering anemone a distinct appearance that is hard to miss.
Not only do these vesicles give this anemone a distinct beauty, they also come in a wide range of colors.

They get their namesake by the fact that they are able to detach and use their tentacles to crawl from location to location. They are often seen at night moving to a more favorable feeding area and have fascinated divers for years. It is not hard to see why as the chance to see a normally sedentary creature deciding that it needs new scenery is quite the novel experience. They are also able to move about in a less active fashion by simply releasing from their hold and letting the current or tidal surge move them along.

They feed primarily at night where they prey upon drifting particles, small invertebrates and even the occasional small fish.

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References:
Closed Anemone Photo
Open Anemone Photo
Scuba Equipment USA - Marine Species Gallery
http://wdg.rexedra.gen.nz/life/5anemone.htm

Phronima, makes a morbid nursery

Phronima or as her friends call her, the Pram Bug, is a highly specialized amphipod that has taken the motto "waste not, want not" to heart. But before I get to that, let me introduce you to this all to often overlooked crustacean.

The many eyes of Phronima.

Phronima is a genus of very specialized amphipods. Each comes equipped with four eyes. This has nothing to do with myopia but an adaptation where two of its eyes are constantly fixed in an upward gaze while the other two eyes are focused on the world ahead or the task at hand. Its two stargazers are, what at first inspection, appear to be some sort of crest upon the amphipods head. The other two eyes are forward facing and on movable stalks for better seeing in many directions.


If you happen to have a submersible, you would find these critters throughout the pelagic zone (essentially every part of the deep ocean other then the ocean bottom). In this state your average Phronima would look something like this:

Did I forget to mention that they are almost entirely transparent?

Your typical solitary variety of salp.

But remember that thing I stated about "waste not, want not"? Well now is when I get to tell you about that as well as a harrowing story of a single mother gaining and maintaining a home for her precious children. Enter the pregnant mother, desperate for a home, unfortunately it is the middle of the ocean so rental property is a bit hard to come by. But this does not dissuade her, for she knows something better then real estate tips. She knows how to find salps. For those who have not heard of these members of the oceanic plankton, sapls are mobile tunicates, Sea Squirts that couldn't stand becoming a sessile brainless filter feeder so instead settled for being a free-swimming brainless filter feeder.

But as we said, our mother Phronima is in desperate need of a home and when that delicate little salp comes along it is the very solution to all her problems.  The only thing stopping Phronima from moving into this nice cylinder of tunican is all these messy internals.  But being pregnant, Phronima could do with a bit of a meal, so she begins eating the insides out of the hapless salp (it is almost a pun yet far enough to be safe, amazing).   Once all that messy internal tissue is done away with, Phronima can get around to her main goal of raising her family.  So she lays her eggs along the inside of the hollowed out salp and continues to swim along with it so that it will get plenty of fresh water and nutrients flowing by.  This leaves our once homeless mother with not only a chic new house but the foundings of a whole new brood, a brood that will continue on  living the double lives of the female Phronima, part free living, part necro-parasitic, as Michael Bok described it. Michael, on his own blog, also shows how this endearing little creature may have been the inspiration for the Alien Queen from the film Aliens.

As cozy as one could be in a corpse.

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References:
Photo, Phronima eyes: Woods Hole Oceanographic Institute, Mike Land
Photo, Corpse home.
Arthropoda

Macropinna microstoma the Barrel-Eyed Fish

Macropinna microstoma is a species of fish that shows that the evolutionary process really does not care as long as you have a survivable species. While most of its body is normal, its head looks like it should have been part of a submersible. You see, the Barrel-Eye, as it is commonly known, has decided that having eyes on the outside of its head was just some passing trend. Instead, it prefers to keep them inside the confines of its transparent head for safe keeping.

This fish laughs in the face of conformity.

Bizarre little critter, isn't it? Now that image needs a bit of explaining as the normal features one would expect just aren't right on this thing. Those two things up front that look like a cartoonists representation of eyes are in fact its nares. Nares are the olfactory structures of fish. These sensing organs are usually not quite this noticeable on your average fish, but the Barrel-Eye has a particularly developed set. The fact that they are facing forward on a transparent dome only makes them more conspicuous.

The real eyes are the two bubble looking structures inside the head. Those bubbles are actually massive lenses used by the fish to focus the dim light better. They get their name for the fact that the entire eye is cylindrical like a barrel. They tend to stay mostly motionless in the water column (which explains the large fins) with its eyes facing upward hoping to spot the silhouette of passing prey items. Also of note is the fact of the green pigment in the eyes. It is hypothesized that this is designed to filter out the last bits of natural sunlight that reaches the fish (as green light penetrates the deepest) so that it can focus on the bio-luminescence of its intended meal. The eyes get even stranger when you realize they can rotate to face forward.

Never has the simple turning of the eyes looked so strange.

So why does this fish have its eyes encased in that fluid filled head of its? The best guess comes from the prey items of this fish. Stomach contents show that it preys on sea jellies frequently. Having its eyes enclosed would allow them to be out of the reach of the cnidocytes (stinging cells) on the jellies tentacles. Another hypothesis is that the Barrel-Eye actually steals prey caught by siphonophores. Siphonophores being a colonial species of Cnidarian (the phylum all sea jellies, anemones, corals and hydras belong to) that looks like a long rope with tentacles along the length in clusters for catching prey.

The siphonophore Praya dubia, which may be one of the longest organisms with a length recoded to over 40 meters (131 feet)

Siphonophores are one of the more efficient hunters of the deep oceans, so feeding off of their catches would be a great strategy for a fish to develop. Even better, most siphonophores use bio-luminescence to attract prey, the green tinted lenses mentioned earlier would be especially helpful in picking this out.

The Barrel eye has been noted to live at the depths of 600 meters (2,000 ft) to 800 meters (2,600 ft), so unless you have access to a deep water submersible, there is little chance of encountering this critter on your next dive. Once again proving that the deep ocean gets to have all the crazy creatures.