The Dorsal Fin

A photo taken off Encinitas, California has been making news as of late. San Diego’s CBS 8 reports that the photo was taken off Swamis beach, and that a “local shark expert who confirmed that the shark in the photo is a 10 to 12 foot great white.”

While the CBS 8 report seems to take the stance that the image does, in fact, show a large shark, Encinitas Lifeguard Sgt. Robert Veria told CBS 8 that he believes the image is that of a surfer performing a duck dive and that the “fin” seen in the picture is merely the bent leg of the surfer. Additionally, none of the surfers in the water, many of whom appear to be in close proximity to the shape that is being referred to as a shark, reported seeing a shark.

A report on the photo also appeared on The Early Show which airs nationwide on CBS.

Is this an image of a white shark’s caudal fin or just a surfer’s leg? Feel free to sound off in the comments, if you have an opinion on the photo.

WARNING: Video features offensive language and graphic content

YouTube user ograza13 recently uploaded the video above which shows a young great white shark being caught, according to the video description, from Huntington Beach Pier.

It should be noted that fishermen involved apparently thought it was a mako, as you can hear one of them say “c’mon mako!” Based on the title of the video, it can be assumed that YouTube user ograza13 still wasn’t sure of the species, when the video was posted. However, it’s quite clear from the video that this is a white shark (Carcharodon carcharias), which is a protected species in California waters.

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.

Sad news out of California yesterday as a 19-year-old University of California Santa Barbara student has died due to wounds from a shark attack, which occurred just after 9AM local time. The man was boogie boarding about 100 yards from shore when he was bitten on the leg by what has been described by officials as a shark that is “14 to 20 feet in length,” according to ABC News.

The species of shark involved has not been officially identified, according to a CBS report, which speculates the species was a great white shark. Drew Sugars, of the Santa Barbara County Sheriff’s Office, told CBS that they hope to have the species identified by Monday and that they plan to use teeth marks from the boogie board to determine the species.

Matthew Garcia, a friend of the victim, was only a few feet away when the attack occurred. Garcia attempted to rescue his friend and brought him into shore. Unfortunately, the victim was pronounced dead after further resuscitation attempts after he was brought to shore.

The victim was described by one friend as “the happiest kid in the world,” and by another who said he was a nice guy who “loved life.” My thoughts and prayers go out to the victim and all of his friends and family.

White shark attacks on sea otters along the central coast of California hit record numbers for the month of August, this year, according to a 760KFBM.com report. The average number of shark attacks on sea otters for the month of August over a ten-year period is seven. In August of this year, scientists recovered 19 otters with apparent shark bite wounds.

Typically, when a white shark attack does occur on a sea otter, the shark will bite and then release the sea otter upon realizing that it a preferred prey item, according to Mike Harris of the California Department of Fish and Game. Harris goes on to note that unfortunately most of these attacks still prove fatal. Due to the nature of the severity of the bites and the anatomy of the sea otters, even an exploratory bite or a bite of “mistaken identity” can result in injuries that the sea otters cannot recover from.

The 760KFMB article notes that some researchers are speculating that unusually mild summer temperatures in the area might explain the increase in the incidences involving white sharks attacking sea otters, as the cooler ocean temperatures make area waters preferable to white sharks.

In addition to the shark attacks on sea otters, a New York Times article is reporting that a University of California, Santa Cruz report has linked sea otter deaths in California to a freshwater toxin. The toxin microcystin is produced by blue-green algae, and the report suggests that the toxin has leaked into the Pacific. Researchers involved in the study say that least 21 sea otter deaths were linked to the toxin.

Both sea otters and white sharks are listed as threatened species on the IUCN red list. Sea otters are classified as “endangered,” while great white sharks are currently classified as “vulnerable.”