The Dorsal Fin

Great white shark attacks on California sea otters are on the rise, according to the USGS.

California sea otters (Enhydra lutris nereis) appear to be experiencing an increase in mortality rates as a result of bites from white sharks (Carcharodon carcharias), according to a USGS press release. Tooth fragments and bite wound characteristics were used to identify white sharks as the species primarily responsible for the attacks on the otters.

USGS and DFG biologists and veterinarians have been documenting sea otter deaths since 1968. The data recorded indicates that shark bites accounted for about 8% in the 80s and early ’90s. However, that number rose to about 15% by the late 90s. Current estimates place the percentage of sea otter deaths caused by shark bites at approximately 30%.

Other natural causes of otter deaths recorded include mating trauma, starvation, infection, and heart disease. Additionally, boat strikes and gun-shot wounds were also among the reported causes of death for the federally listed threatened species.

For more information, check out the full report at USGS.gov.

UPDATE Jeffrey Gallant – GEERG (Greenland Shark and Elasmobranch Education and Research Group) has commented that this is more likely a southern sleeper shark (Somniosus antarcticus), and could also possibly be a Pacific sleeper shark (Somniosus pacificus). However, it is “virtually impossible” to tell based solely on imagery.

The crew aboard of the Stena DrillMAX caught some amazing footage earlier this month of what appears to be a large Greenland shark (Somniosus microcephalus) recorded at over 9,100′ (2,770m) deep. To give a frame of reference, the pipe seen in the background is approximately 5′ (1.5m) in diameter. The depth (in feet) can be seen on the video in the upper-right corner.

The footage was recorded by ROV (remotely operated vehicle) about 300 miles (400km) off the coast of Brazil on February 11, 2012.

The Florida Museum of Natural History notes that a Greenland shark was recorded in 1988 at 7,218 feet (2,200 m) at the wreck of the SS Central America off Savannah, Georgia, USA. This is the greatest depth on record that I’ve been able to find, prior to the depth documented in the Stena DrillMAX video above which exceeds the 1988 recorded depth by about 1,900′ (over 500m).

If anyone has any other information about maximum recorded depths of sleeper sharks caught on film, please let me know, so I can pass it on to the Stena DrillMAX crew. Thanks!

San Diego’s CBS 8 recently interviewed Buck Elsmore, a stand-up paddle-boarder who was featured in a photo with the dorsal fin of white shark (Carcharodon carcharias). The photo was taken last fall off Encinitas’ Moonlight Beach.

Elsemore told Channel 8 that the shark swam near him at the surface for around a minute before descending back to deeper water.

The trailer for Halle Berry’s new shark horror flick, “Dark Tide,” showed up online today. The trailer features the typical shark attack movie fare, but it also features some of Guadalupe’s great white sharks, most notably Cal Ripfin (aka Shredder) who can be seen at 38 seconds in.

“Dark Tide” follows the story of a “shark expert” played by Berry who is involved in a shark attack but later returns to the water after a lucrative proposition from a wealthy thrill-seeker who wants to dive with white sharks outside of the cage. While some of the shark footage was shot at Guadalupe, it appears that the story mainly takes place in South Africa.

If you’re looking for a documentary about white sharks, this isn’t it. Rather it looks to be another horror/thriller with white sharks as the main antagonists (although the storm in the preview looked pretty threatening, too). So, don’t be surprised if your favorite Guadaupe white shark ends up being playing one of the villains in “Dark Tide.”

“Dark Tide” opens March 30, 2012, and is rated PG-13 for “bloody shark attacks and disturbing images” among other things.

Staff at China’s Yantai Haichang Whale and Shark Aquarium have caught the birth of a nurse shark pup on film. The staff at the aquarium were keeping an eye on the expectant shark round the clock in order to capture footage of the birthing event. The newborn shark was removed from the main aquarium area to protect it from other predators but will be returned when it’s older.