#bathyraja

[every-day-creechur]

Roughtail Skate Bathyraja trachura

Lives in the North Pacific Ocean. Its habitat is benthic, mud, canyon walls, and other hard substrate.

[todropscience]

DEEP-SEA SKATE USES HYDROTHERMAL VENTS TO INCUBATE EGGS

The discovery of deep-sea hydrothermal vents in 1977 challenged our views of ecosystem functioning, continually revealing unique biological processes. Now, experts report for the first time, a unique behavior where Pacific White Skate Bathyraja spinosissima, a deep-sea species, appears to be actively using the elevated temperature of a hydrothermal vent environment to naturally “incubate” developing egg-cases. 

In 2015, an international team of researchers used a remotely operated underwater vehicle (ROV) to survey in and around an active hydrothermal field located in the Galapagos archipelago, 28 miles north of Darwin Island.

The researchers found 157 egg cases in the area and collected four with the ROV's robotic arm. DNA analysis revealed that the egg cases belonged to Pacific White Skate. About 58 percent of the egg cases were found within 20 meters of a black smoker, the hottest kind of hydrothermal vent, and 89 percent of the egg cases were laid in water that was hotter than the background temperature of 2.76 C°. Researchers believe that the warmer temperatures in the area could reduce thE incubation time of the eggs.

- Clutch of egg-cases with dark brown coloration.

Similar egg incubating behavior, where eggs are incubated in volcanically heated nesting grounds, have been recorded in Cretaceous sauropod dinosaurs and the rare avian megapode. To our knowledge, this is the first time incubating behavior using a volcanic source is recorded for the marine environment. Hydrothermal vents are being targeted for deep seabed mining, and the oil and gas industry drills on the margins of methane cold seeps. Their destruction by bottom trawling or mining will impact populations of deep-sea skates.

Photo:  collection of egg-case using the Hercules ROV robotic arm.

Reference: Salinas de León, et al., 2018.  Deep-sea hydrothermal vents as natural egg-case incubators at the Galapagos Rift. Scientific Reports

[brilmansverzameling]

Bathyraja brachyurops (blonde rog) Eikapsel De Zandmotor 20-9-2015

[dailyelasmobranch]

Deepsea skate - Bathyraja abyssicola

The deepsea skate's depth range of between 1,148 and almost 9,528 feet makes it one of the deepest known species. It is found in the northern Pacific from California through the Bering Sea to the central coast of Honshu, Japan, and feeds primarily on benthic invertebrates. It is believed that females reach at least 5 ft. in size. As it is rarely encountered there is not currently enough data available to determine its status, though it is known to be taken as bycatch by deep commercial trawls and traps.