Tagged Pacific

What happened to the legendary great white shark, Cal Ripfin?

Now, that August has arrived it’s about that time of year when great white sharks (Carcharodon carcharias) begin to arrive at Mexico’s Isla de Guadalupe Biosphere Reserve. The island is regarded as one of the best places on Earth to view white sharks in their natural habitat. However, it’s one shark in particular that many are holding out hopes to see return.

Cal Ripfin great white shark
Cal Ripfin (aka Shredder) was one of the most well-known great white sharks at Guadalupe prior to his disappearance following the 2011 season.

From 2001 to 2011, Cal Ripfin (aka Shredder) was one of the most well-known great white sharks to visit Mexico’s Isla de Guadalupe. Easily recognized by an injury to his dorsal fin that occurred sometime between the 2004 and 2005 season, Cal was a “fan favorite” of divers and photographers due to his inquisitive and curious nature. He would often swim right up the cameras as if he was posing for a photo opportunity.

White sharks gather at Guadalupe in the later months of the year, with the prime season considered to be between August and November. Cal consistently visited Guadalupe every season for 10 years straight, and his arrival was generally quite predictable. In 2009, he was absent early on in the season, which caused a bit of concern among researchers and divers, but he eventually showed up about midway through the season. However, after failing to be seen during the 2012 season, concerns once again rose for the well-being of Guadalupe’s favorite shark. When 2013 and 2014 passed by without any sighting of Cal Ripfin, hopes of his return were dampened even further.

great white shark close-up
Cal Ripfin (aka Shredder) wasn’t shy about swimming right up to the camera, which often created great opportunities for close-up shots.

While migratory tracking data is limited among Guadalupe white sharks, the available data indicates that SPOT tagged males follow a somewhat predictable pattern each year. The data shows males traveling to Guadalupe in the latter half of a year, and spending the rest of their time in the Shared Offshore Foraging Area (SOFA) (aka “the White Shark Cafe”), a remote area in the mid-Pacific. If the tracking data available is representative of the migratory behavior of all male Guadalupe white sharks, it does not bode well for Cal Ripfin, given his 3-year absence.

Cal Ripfin great white shark
The question of why this male great white shark suddenly stopped returning to Guadalupe is one that will likely go unanswered, unfortunately.

So, what could have happened to him? Did he change his migratory routine? Did he die of natural causes, fall prey to another predator, or end up in a fishing net? At this point, it seems likely that his fate will always remain a mystery.

Somehow, I still have a tiny glimmer of hope that he’s still out there, but with each year that glimmer gets a little more faint.

Marine CSI questions white shark population estimate methodology

White sharks observed at the surface were identified by unique markings.

Earlier this year, reports of the results of study which estimated the number of white sharks off central California made headlines. Researchers formulated the estimate after surveying known and unknown white shark specimens, which were observed at the surface. Individual sharks were identified based on each shark’s unique markings.

Dr. Michael Domeier of Marine CSI has recently posted commentary on the methodology used in the above mentioned study. Domeier cites that the study assumed that the sampled white shark population was a closed population. Domeier goes on to say that the long term monitoring of white sharks at Isla de Guadalupe has shown that adult white sharks leave and join the population, which violates the assumption of a closed population.

Additionally, Domeier states that the assumption that individual sharks have an equally probability of being observed has been invalidated by previous research.

Domeier concludes that since estimate was based on “faulty assumptions” the estimate is invalid. He also states that the actual number of white sharks in the respective region is “likely dramatically higher” than the estimate reported in the published study.

Dr. Domeier’s full discussion of this study can be found at the Marine CSI website.

Great white shark versus giant squid: scientific evidence or mere speculation?

Are great white sharks and giant squid doing battle in the depths of the Pacific?
If so, there isn't any solid evidence to substantiate it, at this point.

A recent article that appeared online at the LA Times website suggests that great white sharks (Carcharodon carcharias) and giant squid (species from the Architeuthis genus) might “battle” it out in the depths of the Pacific. The theory, which other media outlets are running with as if it were scientifically proven, seems entirely based on research of migratory patterns of white sharks being conducted by Michael Domeier.
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