If dolphins weren’t such a$$holes, they would gently cradle the octopus like a kitten, stroking its mantle and respecting the cephalopod’s amazing intellect. But who are we kidding! This is a dolphin we’re talking about, and marine mammal researchers have found that dolphins “shake and toss” cephalopods like a dog tearing apart his favorite chew toy:

Why is this dolphin such an a$$hole to the octopus? Probably because cephalopods are yummy but dangerous food – they’re smart and sucker-y, and dolphins run the risk of *suffocation* if the octopus isn’t fully torn apart and incapacitated before meal time. As Sprogis et al. (2017) found, death by octopus tentacle is surprisingly common:

It is apparent that octopus handling is a risky behavior, as within our study area a known adult male stranded and a necropsy confirmed the cause of death was from suffocation from a large 2.1 kg octopus.1 The dolphin had attempted to swallow the octopus, however, the octopus was found almost intact, with the head and the mantle of the octopus in the dolphin’s stomach and the 1.3 m long arms separated from the head and extending out of its mouth.1 Similarly, another T. aduncus [dolphin] died from suspected asphyxiation due to an octopus lodged in its mouth and pharynx approximately 140 km north of our study area (Shoalwater Bay Islands Marine Park).2 In these two cases, the dolphins may not have processed the octopus sufficiently by shaking and tossing it to ensure the arm’s reflex withdrawal responses were inactive. Octopus arms have a defensive response, as their receptors can detect stimuli that cause damage to their tissues (Hague et al. 2013). These receptors allow octopus arms to continue reacting even after the arms have been detached from the head, allowing the arms to coordinate a reflex withdrawal response (Hague et al. 2013). Dolphins must therefore process the octopus sufficiently to reduce the arms reflex withdrawal response and limit their suckers adhering to them, which otherwise would make them difficult to swallow.

So mad props to all the octopuses out there, for fighting the good fight against dolphins (and sometimes winning!)

Here’s the frame-by-frame photo in all its glory (Figure 1 from the below paper):

Reference:

Sprogis KR, Raudino HC, Hocking D, Bejder L (2017) Complex prey handling of octopus by bottlenose dolphins (Tursiops aduncus), Marine Mammal Science, doi: 10.1111/mms.12405

The post Reason 5,879 why dolphins are a$$holes: Octopus “handling” first appeared on Deep Sea News.

In humans concentrations of carbon dioxide around 1%, normal is just a less than 0.04%, can make a person drowsy. Like a macroeconomics class.  At 10% concentration, even with enough oxygen, carbon dioxide can result in dizziness, headaches, loss of hearing and sight, and unconsciousness. Much like a Grateful Dead concert. In the oceans, things work a little bit differently, but the end result is equally detrimental.  Increased carbon dioxide concentrations in the atmosphere lead to the acidification of the oceans.  Under future CO₂ emissions, the pH of the oceans could decline a further 0.3–0.4 units. The oceans now are 0.1 units lower in pH and 30% more acidic than before the Industrial Revolution.  A more acidic ocean more readily dissolves shells and skeletons of marine organisms made of calcium carbonate.  Acidic oceans also change how animals react to the ocean around them—including hungry predators.

Gibberulus gibbosus, previously Strombus gibberulus gibbosus, goes by many common names but the most badass of these is the Tonga Fighting Conch.  You think with such an awesome name that this beast would have few enemies to contend with.  However, the sworn enemy of the Tonga Fighting Conch is the Marbled Cone, Conus marmoreus. This Dalmatian spotted wanna-be is nothing but a evolutionarily honed snail eating machine with a modified poisonous harpoon that can be ejected from its body to subdue any prey.  In the video below a Marbled Cone attacks a Common Periwinkle.  At 1:35 you can see the Cone actually inject poison into the doomed Periwinkle. This eventually causes paralysis in the Periwinkle that opens up their trap door, the operculum, allowing the Cone to feed.

Under high CO₂, overturned conchs were still able to right themselves as quickly and with the same number of foot flicks as their brethren in normal seawater.  This suggest that the physical ability to escape is not effected by high CO_2. However, antipredator escape behavior did change.  In cage matches between cones and conchs, 65% of the conchs jumped away.  In high CO₂ only 33% jumped.  Not only did less jump in high CO₂, conchs took on average nearly 30 seconds longer to jump away. These high CO₂ conchs also jumped in trajectories that kept them close to the predators.  In normal conditions, conchs angled away from the predator.

The researchers were able to restore the Tonga Fighting Conchs under high CO₂ with a shot of Gabazine.  Acidic conditions change ion gradients within organism causing neurotransmitter receptors to malfunction.  The inappropriate firing of one type of neurotransmitter receptors (GABA_A receptors) is affected by these ion gradients and cause odd behavioral response.  Gabazine blocks this the GABA_A receptors and prevents this behavioral response.  Tonga Fighting Conchs in high CO₂ and Gabazine performed normally when faced with the Marble Cone.

Watson S-A, Lefevre S, McCormick MI, Domenici P, Nilsson GE, Munday PL. 2014 Marine mollusc predator-escape behaviour altered by near-future carbon dioxide levels. Proc. R. Soc. B 281: 20132377. http://dx.doi.org/10.1098/rspb.2013.2377

The post Snails High On Acid Make Poor Choices, Get Eaten By Predators first appeared on Deep Sea News.

 The short answer is not as many as you think.

I spent Saturday watching Pacific Rim.  The movie has everything I want in a flick—big-ass sea monsters, big-ass robots, and big-ass robots fighting big-ass sea monsters.  Pacific Rim is undoubtedly the no-holds-bar-over-the-top-action-flick-who-gives-damn-about-plot-or-character-development-o-yeah-it-has-Ron-Motherf’n-Perlman kind of movie we all need.  My wife disagrees but I still love her.

The stars of Pacific Rim are the Kaiju (怪獣) a Japanese word that literally translates to “strange creature”.  Kaiju films are a staple of Japanese cinematography with Kaijuu, like Godzilla, Mothra, or Rodan, attacking each other or better yet a whole city.

Being the complete nerd I am, I waited patiently until I heard the magical words I needed to hear during the move. “That Kaiju weighed 2500 tons.” At 2500 tons and a puny category 3, this monster didn’t even top the scales as the largest.

Kaiju are creatures of a highly toxic nature and have been categorized on the “Serizawa Scale”. Each Kaiju is classified under five different categories. Categories 1 through 2 represent the weakest of the Kaiju, while Categories 3 through 5 are the strongest. The Serizawa Scale measures water displacement, toxicity and ambient radiation levels given off by their bodies when they pass through the breach.

Knowing a Kaiju’s weight I can tell you a lot about Kaiju biology, like how many humans they need to eat per day to survive.

First we need to calculate what is the field energy expenditure, i.e. the number of joules per day to survive, for a Kaiju.  During the film the “scientist” states the Kaiju are related to the dinosaurs.  A previous paper suggests the equation for dinosaurs should be based on those for Komodo Dragons, i.e. active carnivorous lizards.  So

2500 tons = 2,267,961,850 grams

The equation is

FFE=1.07(mass)^0.735

FFE=8.05*10^6 kJ/day

Given the 2500 ton size of the Kaiju, you might be surprised this doesn’t come close the energy demand, 10.14*10^6 kJ/day, for a blue whale at a mere 160 tons.  The Kaiju estimate is just a single order of magnitude higher than that of elephants and rhinos, 5.36*10^5 and 7.10*10^6 kJ/day.

So what’s going on? The FFE is higher for carnivores than herbivore. More energy is required to chase and subdue prey.  That constant search for prey may also require muscle structure for endurance [pdf], increasing muscle mitochondria density, and requiring more energy.  But we accounted for that by using the total bad us flesh munching, bone crushing Komodo Dragon equation.

The real reason? Lizards don’t run as hot as mammals, i.e. they don’t regulate their internal temperature. Komodo Dragons, an active carnivorous lizard, actually do heat up bit, but still don’t suck energy like a mammal.  Keeping the body warm is energetically expensive to maintain, as exampled by heating bills in Boston to keep my Southern butt warm.

So real question is how many humans would a Kaiju need to eat daily to survive?  The human body contains, depending on athleticism, anywhere from 600,000 to 750,000 kilojoules of energy.  Per day the Kaiju would need to eat anywhere between 10.7 to 13.4 humans.  This would mean that it would take a Kaiju, at the quick side, 1,472 years to to eat through the population of Hong Kong, home of the Shatterdome base.

If we assume a Category 5 Kaiju weighs 5,000 tons, then it would only need 17.9 humans per day, taking it 1,102 years to eat its way through Hong Kong.  Perhaps we shouldn’t be so worried about them.

The post How may people does a Kaiju need to eat every day? first appeared on Deep Sea News.

Wait for the M. Night Shyamalan twist ending.

The post Seasnake vs. Moray Eel…not what I was expecting first appeared on Deep Sea News.

Hagfish can produce copious amounts of slime from 90 to 200 slime pores that run the length of their body. With these dedicated sliming glands, a single hagfish can produce over a gallon of mucus in single sliming event. The video below should convince you that the hagfish’s superpower is to produce a slimepocalypse. What should a hagfish use this power for? Create a slip and slide for friends at parties? Lubricate the chassis of a fleet of 18-wheelers hauling bourbon out of Kentucky? Defeat the forces of evil?

Hagfish choose not to get eaten by predators because with great power comes great responsibility—like not getting eaten.

Recent work by Vincent Zintzen and others video documents for the first time hagfishes choking would-be predators with gill-clogging slime. When a hagfish finds itself in the mouth of the would-be predator, the slime glands of the hagfish inside the predator’s mouth fire off. Within as little as 4 seconds, 14 different predators in Zintzen’s recorded footage (embedded below) fell victim to the slimepocalypse. Each predator, be shark or fish, “convulsed their gill arches dramatically in a gagging-type effort to clear the slime from their gill chambers.” Whether the predator was a biter like sharks and conger eels or a sucker like wreckfishes and scorpionfishes, hagfish slime prevailed.

In addition, hagfish can also use their super slime power to deter competitors. In the words of the author, “when multiple hagfish were present at the bait, the bait bag would become draped in slime, deterring other fishes from approaching the food source.”

But predators and competitors are not the only ones to feel the slimepocalypse. Hagfish are typically viewed as scavengers but Zintzen and colleagues observe hagfish preying on red bandfish (video embedded below). Upon locating a burrow, the hagfish enters and tangles with the prey using its retracting dental plates to begin swallowing the unlucky victim. At this point the hagfish waits for the victim to die and may suffocate its prey with slime, similar to the hagfish’s predators. To retract the bandfish from the burrow the hagfish knots the part of its body outside the burrow to provide leverage to both remove itself and the victim.

Unfortunately, Zintzen and friends do not document increased attraction of lady hagfish to males who produce slime. But why wouldn’t the ladies love it? During The Operation I might have faired better with other males if I was hagfish, but more research will be required to determine if I would have attracted or repelled my Tall Blond.

Zintzen V., Roberts, C.D., Anderson M.J., Stewart A.L., Struthers C.D. & Harvey E.S. (2011) Hagfish predatory behaviour and slime defence mechanism. Scientific Reports 1, 131

http://www.nature.com/srep/2011/111027/srep00131/full/srep00131.html

The post If I Was A Hagfish Could I Get With Tall Blonds? first appeared on Deep Sea News.

The 285  macrourid fishes, the rattails, whiptails, and grenadiers, are one of, if not the, most abundant fish in the deep.  You cannot throw…well anything…without hitting one.  What do all these fish eat?  In one scenario, macrourids feed on organisms living on the seafloor, that in turn originally feed on detritus, i.e. marine snow, raining from the surface.  Or these fish could cut out the middle man and feed directly on dead prey originally from surface. Or they could do both?

In simplified terms, phytodetritus is consumed by deposit feeders, which in turn are consumed by primary carnivores and so on to the top trophic positions including many fishes.  However, an alternative trophic pathway exists. Many deep-sea fishes are attracted to cameras baited with pelagic carrion and a few studies have noted carrion in their diets.  However, these observations have rarely been quantified. Scavenging on the sunken carcasses of epipelagic nekton bypasses the conventional benthic food web, although the beginning of each path shares primary production in surface waters. The relative importance of these 2 trophic pathways remains uncertain.

The question may seem trivial but the answer gets at nothing less than the pathway of carbon into the deep, and impacts how we understand carbon cycling and sequestration. A new study by Drazen et al. in Marine Ecology Progress Series examines the fatty acids of two macrourids and a whole host of their potential prey items.  All the samples were collected from the well-known Station M site (see map).

[googlemap lat=”34.9″ lng=”-123″ width=”500px” height=”500px” zoom=”7″ type=”G_HYBRID_MAP”]Station M[/googlemap]

What is generated from the data are the two plots below.  All you need to know is that the closer two points are on the graph the more similar the fatty acid content of their tissue.  The first plot is for macrourids and benthic prey and the second plot adds a few more pelagic prey.  Macrourids are black, echinoderms green, polychaetes, orange, anemones purple, crustaceans blue, and either living or dead on the seafloor, depending on the plot, pelagic species in red.

So it is obvious what is going on here , right?  Benthic crustaceans and pelagic-derived carrion taste good.  Echinoderms and polychaetes not so much.

So Number 1, as the press release for this paper states “This indicates that epipelagic populations constitute a significant part of the diet in abyssal fishes”, and thereby circumventing part of the food web.  And Number 2, no doubt making Chris Mah smile, and a bit of conundrum, is that they do not eat echinoderms.  As Chris Mah would quickly tell you, probably over cocktails at a party, echinoderms are one of the most dominant taxa in the deep.  You cannot throw a macrourid without hitting one.  Why do macrourids, obviously opportunistic scavengers/predators, not eat the most abundant food source in the deep?

Drazen, J., Phleger, C., Guest, M., & Nichols, P. (2009). Lipid composition and diet inferences of abyssal macrourids in the eastern North Pacific Marine Ecology Progress Series, 387, 1-14 DOI: 10.3354/meps08106

The post Simple Summer Recipes for Dead Seafloor Carrion first appeared on Deep Sea News.

This Wired piece on the 10 Worst Evolutionary Designs also made me want to smash some test tubes. It’s a stunningly inane list of animal adaptations that the author thinks are weird, uncontaminated by even the most basic knowledge of evolution.

And the eight days since reading the Wired piece, I have yet to become less irritated by it. Miriam goes on to state at least one problem…

It isn’t cool enough that a cow-like mammal has evolved into a denizen of the open sea? It isn’t neat that dolphins have evolved amazing echolocation, and that humpback whales use their air-breathing abilities to hunt? (Not to mention that only cetaceans—whales and dolphins—have blowholes. Other sea mammals, like seals and manatees, just stick their noses in the air.) Evolution is all about using the tools at hand, and if something works it’s good enough. Whales can’t evolve gills out of nothing, but they can move their nostril to the back of their head and be successful. Kangaroos can’t suddenly evolve a placenta, but being a marsupial works fine.

So as expressed by Miriam the post misses key concepts in evolutionary biology

• As Miriam states, future evolution is constrained by the past.  Once an organism starts down a genetic road, it can always veer off and take a slightly different direction, but don’t expect to make it to Tokyo on the road to Tulsa.
• Not all features of an organism are adaptive.  Some features are hitchhikers, remnants of the past no longer needed.
• One cannot examine singular features in isolation.  An organism should be examined in totality where organismal features represent a balance of environmental constraints.  For example, evolutionary miniaturization of organisms often results in loss of organs or organ systems.  Instead of saying “Gee is sure is stupid that that fish has no circulatory system”, one should be in awe that organism can lose an entire organ system, question why the organism would need to become small in the first place, and contemplate the evolutionary marvel of solving this problem by organ loss.
• On the same line of thought as the above, features themselves can represent a balance of selective pressures.  Back to organismal size again, my personal forte, size can represent a balance of  life history constraints, metabolic constraints, space availability, predator/prey relationships, and energetics (food foraging area, fasting potential, food availability).  Each of these may select for opposing sizes and the eventual size represents one solution to a complex evolutionary equation.
• Value judging an organism’s features is ridiculous in itself.  I personally find that “A few shark species have live births (instead of laying eggs). The Jaws juniors grow teeth in the womb. The first sibling or two to mature sometimes eat their siblings in utero.” to be an excellent, fascinating, and brilliant example of how to both reduce sibling rivalry for resources but increase your own energy consumption prebirth!

The post Worst Evolutionary Designs? No! Brilliant Solutions to the Complexity of Nature and Constraints first appeared on Deep Sea News.

The post TGIF Bonus: Cuttlefish Eats Octopus first appeared on Deep Sea News.