Cephalopods may be Spreading due to Climate Change

Humans have changed the world's oceans in ways that have been devastating to many marine species. But, according to new evidence, it appears that the change has so far been good for cephalopods, the group including octopuses, cuttlefish, and squid. The study reported in the Cell Press journal Current Biology on May 23 shows that cephalopods' numbers have increased significantly over the last six decades.

"The consistency was the biggest surprise," says Zoë Doubleday of Australia's Environment Institute at the University of Adelaide. "Cephalopods are notoriously variable, and population abundance can fluctuate wildly, both within and among species. The fact that we observed consistent, long-term increases in three diverse groups of cephalopods, which inhabit everything from rock pools to open oceans, is remarkable."

According to the researchers, there has been growing speculation that cephalopod populations were proliferating in response to a changing environment, based partly on trends in cephalopod fisheries. Cephalopods are known for rapid growth, short lifespans, and extra-sensitive physiologies, which may allow them to adapt more quickly than many other marine species.

link.

Giant Squid Surfaces off Coast of Japan, Tokyo Surprisingly NOT Destroyed

Crab Meets its own Face Hugger

facehugger, guys.

Maastrichtian Cretaceous Cephalopods of Seymour Island Uneffected by Environment Changes Until KT Extinction

Evolution and extinction of Maastrichtian (Late Cretaceous) cephalopods from the López de Bertodano Formation, Seymour Island, Antarctica

Authors:

Witts et al

Abstract:

One of the most expanded records to contain the final fortunes of ammonoid cephalopods is within the López de Bertodano Formation of Seymour Island, James Ross Basin, Antarctica. Located at ~ 65° South now, and during the Cretaceous, this sequence is the highest southern latitude onshore outcrop containing the Cretaceous-Paleogene (K–Pg) transition. We present comprehensive new biostratigraphic range data for 14 ammonite and one nautiloid species based on the collection of > 700 macrofossils from high-resolution sampling of parallel sedimentary sections, dated Maastrichtian to earliest Danian in age, across southern Seymour Island. We find evidence for only a single, abrupt pulse of cephalopod extinction at the end of the Cretaceous when the final seven ammonite species disappeared, consistent with most evidence globally. In the lead up to the K–Pg extinction in the James Ross Basin, starting during the Campanian, ammonite diversity decreased overall, but the number of endemic taxa belonging to the family Kossmaticeratidae actually increased. This pattern continued into the Maastrichtian and may be facies controlled, linked to changes in sea level and seawater temperature. During the early Maastrichtian, ammonite diversity dropped significantly with only two species recorded from the basal López de Bertodano Formation on Seymour Island. The subsequent diversification of endemic taxa and reappearance of long-ranging, widespread species into the basin resulted in an increase in ammonite diversity and abundance during the mid-Maastrichtian. This was coincident with an apparent period of warming temperatures and sea level rise interpreted from palynology and sedimentology, perhaps reflecting a high latitude expression of the Mid-Maastrichtian Event. Late Maastrichtian diversity levels remained stable despite reported climatic and environmental variation. Ammonite diversity patterns during the Maastrichtian parallel those of microfossil species such as nannofossil and planktonic foraminifera, suggesting that dynamic climatic and environmental changes affected many planktonic and nektonic organisms during the latest Cretaceous. However, we suggest that these perturbations had a minimal effect on overall diversity prior to the catastrophic extinction event at the K–Pg boundary.

Robopocalyse Coming for the Cephalopods...Again

Humans, and the machines we make, are particularly unwieldy swimmers. Many types of fish can travel at speeds of up to 10 body lengths per second. By contrast, an Olympic swimmer manages no more than about one body length per second. And while nuclear submarines can travel at about 80 kilometres per hour, that translates into much less than half a body length per second.

This kind of performance has long fascinated marine engineers who would dearly love to match it. In particular, they have puzzled over the way certain sea creatures can accelerate from a standing start at rates of up to 120 metres per second squared. That’s 10g!

Among the creatures that demonstrate this extraordinary fast-start acceleration are the octopus, squid and certain jellyfish. Marine biologists have long observed these creatures’ ability to avoid prey by filling their bodies with water and squirting it out to generate propulsion. In this way, the octopus, for example, can accelerate at more than 10 body lengths per second squared.

hat gave Gabriel Weymouth at the University of Southampton and few pals an idea. Why not build their own robotic octopus capable of squirting in the same way and seeing whether it can match its natural cousins’ performance. The results are something of a surprise.

Their underwater robot is essentially a copy of an octopus’s head, which expands when it is filled with water and squirts it out through a nozzle at the rear. This robot has no tentacles but instead, the team fitted small fins to the rear to stabilise its movement through the water.

So the robot is roughly ellipsoidal in shape, measuring 27 centimetres in length and is 5 times longer than it is wide. It is created by stretching a rubber membrane over a set of polycarbonate ribs. Weymouth and co chose this shape because of its ability to glide many body lengths through water.

The team then filled the robot with water under pressure, causing the rubber membrane to expand into a bluff body shape that is particularly unsuited to gliding. Finally, they released the robot in a pool and filmed its progress through the water at a rate of 150 frames per second as water squirting through a rear-facing nozzle propelled it along.

The results are extraordinary. As the water starts to squirt out of the nozzle, the robot begins to accelerate. However, it moves little during the first half second or so since its bluff body shape prevents efficient progress.

But then, as the robot shrinks, it accelerates rapidly. And here’s the thing: Weymouth and co say that its maximum acceleration is 14 body lengths per second squared and that it reaches speeds of 10 body lengths per second.

link.

Mollusc vs Vertebrate War: Battle in the Monterey Bay

nice pop sci write up at the Running Ponies about the squid.

First Octopus Farm Starting in the Yucatan, Mexico

Fish farms now produce million tons of fish each year around the globe. But octopuses have largely escaped this kind of confined aquaculturing, despite a growing global demand and overfishing. Why? That’s the million-ton question.

Based on their brief life cycles, prolific reproduction and efficient metabolisms, octopuses should be ideal candidates for aquaculture. They have short lives, many taking only a year or two to reach full maturity. Females lay thousands and thousands of eggs. And as poikilotherms, they are incredibly efficient at turning calories consumed into body mass.

Groups of scientists and entrepreneurs across the world—from Japan to Australia to Italy to Mexico—have been trying to find a way to rear these finicky creatures from egg to export. And most of them have struggled. But now, one farm has reported success, a move that could help wild populations and researchers alike.

On the Yucatan coast in Mexico, a small cooperative is finally rearing Octopus maya from eggs after a decade of research and unsuccessful attempts, according to news reports. Called Mayab Mollusks, it is still in its infancy, but the group is planning to gear up to larger commercial operations.

link.

Robopocalypse Stalks Cephalopods