Deep-sea anglerfish

©Fundação Rebikoff-Niggeler

Anglerfish: Sensational video from the deep sea

From within their submersible, LULA1000, the deep-sea researchers Kirsten and Joachim Jakobsen filmed a scene which has never been seen before thanks to the submersible’s PLEXIGLAS® viewing dome.

Science is not just any scientific magazine, it is the scientific magazine. Those who are published in it have made a name for themselves in the academic world. In March 2018, the Rebikoff-Niggeler Foundation’s LULA1000 not only made it into the magazine, but also became the number one most popular video on the magazine’s YouTube channel. Approximately 3.2 million people had watched the video within the first week. It featured a fish, or rather, two fish.

Luminescent deep-sea-anglerfish

The scientific name for this type of anglerfish is Caulophryne jordani. There are about 160 different species of these deep-sea fish. One thing they all have in common is their “fishing rod”, which is often luminescent and dangles in front of their terrifying jaws to attract their prey in the complete darkness. However, Caulophryne jordani has its very own special mating ritual, a ritual that the Washington Post described as “the worst sex in the world” upon seeing the photos.

Mating behavior of anglerfish

The female is 16 centimeters long and several times larger than the male. But what Kirsten and Joachim Jakobsen filmed through the 14-centimeter-thick PLEXIGLAS® dome of the LULA1000 has never been seen live before. The male clamps onto the large female with its jaws and feeds from its blood. The female, on the other hand, has its mating partner on hand at all times, which is highly convenient at a depth of 800 meters in the pitch-black waters. Scientists knew this, but nobody had ever seen, let alone filmed, the process before.

Deep-sea anglerfish observed for the first time / Source: Fundação Rebikoff-Niggeler

Viewing dome made of PLEXIGLAS®

“Without the optical quality of the PLEXIGLAS® dome, we would have never been able to film these anglerfish,” says deep-sea researcher Joachim Jakobsen. Despite the 14 centimeter thickness of the material, the delicate, luminous sensors of the anglerfish can be seen in high definition. This was possible as the viewing dome of the Rebikoff-Niggeler Foundation’s submersible is almost invisible under water, thanks to its light transmission and scratch resistance, as well as its high optical purity. This allows the researchers to make high-definition, distortion-free videos at great depths. The PLEXIGLAS® viewing dome is still extremely resilient and stable, given that it must be capable of withstanding the high pressure under water. 

Spectacular film recordings of the anglerfish

Without the optical quality of the PLEXIGLAS® dome, we would have never been able to film these anglerfish.

Joachim Jakobsen
deep-sea researcher

The Jakobsens were able to remain near the 16 centimeter anglerfish for 25 minutes thanks to their 7.5 meter submersible. They were even able to film it in high definition through the dome made for this purpose. The scientists who then saw the recordings were particularly fascinated by the fact that the male followed the female’s movements with agility despite having latched onto her with his sharp teeth. Bruce Robison, deep-sea expert at the Monterey Bay Aquarium Research Institute in Moss Landing, California, told Science magazine, “There’s no way I would have ever guessed that from a [museum] specimen.” And Ted Pietsch, deep-sea researcher at the University of Washington in Seattle, explained, “I’ve been studying these [animals] for most of my life and I’ve never seen anything like it.” Antje Boetius, deep-sea researcher at the Alfred-Wegener-Institut in Bremerhaven said, “I have spent hundreds of hours studying the deep sea, but this is one of the most incredible video recordings of all time. The video impressively shows how different life is in the deep sea and how important it is to observe these animals in their natural habitat in order to understand their behavior and their adaption to the conditions of their environment.”

Discovering the secrets of the deep sea

The unique recordings of the anglerfish aren’t the Jakobsens’ first spectacular discovery: With their LULA1000, they discovered a German submarine which had gone missing during the Second World War and recorded high-definition films of their discovery thanks to the PLEXIGLAS® viewing dome. The two researchers are currently still on the lookout for a giant squid, as they have been for several yearsEvonik has been supporting them in their search since 2013. But the researchers of the Rebikoff-Niggeler Foundation are not the only ones to delve deeper into the world of oceans, they are joined by other scientific and private submersibles as well.

Read more on submersibles with viewing domes made from PLEXIGLAS®: 

Passion for the deep sea Interview with Kirsten and Joachim Jakobsen
The LULA1000 on the lookout for the giant squid
LULA1000 discovers a missing German submarine
Triton Submarines: Luxury in the deep sea
Diving down to the Great Barrier Reef