The next time Jason Dimitri returns to the Western Caribbean to try to remove invasive lionfish, in the back of his mind will loom a recent frightening encounter with an aggressive reef shark.
Dimitri was using a GoPro camera to document his efforts to cull lionfish in Cayman Island waters. Lionfish, in the past decade, have overtaken many Caribbean reefs and threaten the balance of the marine ecosystem.
Suddenly, a four-foot reef shark appeared “out of nowhere” and lunged repeatedly at Dimitri, who used his spear to fend off the strikes until they ceased as he advanced toward the surface.
It’s not clear whether the shark was defending its territory or was simply inspired by the scent of lionfish blood.
Dimitri states in the video description that the encounter occurred at a depth of about 70 feet.
He adds: “I want to make it clear that I am hunting lionfish to help protect the reef from the destruction that they cause.
“The shark was acting in his natural environment. I have no ill will toward him and will get back in the water and continue to protect the reef for future generations.”
The notion that pelagic sharks attack seafaring primates (i.e., Homo sapiens) out of "territorial response" is, in my estimation, a Sociobiological red herring.
As a threshold matter, pelagic sharks that are known to prey on humans (e.g., Oceanic Whitetips/Tiger/White/Bull sharks, et al.) are highly nomadic and, as such, do not exhibit territorial behavior.
This is true towards other sharks to the extent that an ordered hierarchy seems to be established at whale carrion feeding events in the open ocean and elephant seal kills in Northern California around the Farallon Islands.
As such, it seems more than speculative to impute a "territorial response" as an exculpatory theory under any circumstance outside, hmm, humans interfering with Bull shark breeding patterns (see, e.g., Recife shark attack patterns). To be sure, given their symbiotic adaptation along major waterways (e.g., Ganges river; Zambezi river; Amazon river, et al.) Bull shark may have the "closest thing" to a "territorial response" insofar that their "high testosterone, hyper-aggressive" attacking style is a behavioral adaptation to usurp scavenging opportunities (see, e.g., data from sport fisherman on YouTube having game fish taken by Bull sharks in much more "open and notorious" ways than, say, Mako or White sharks' scavenging behavior patterns). But this "aggressive behavior" observed at Bull shark attacks on humans (see, e.g., Daigle attack in FL) is not to be conflated with "territorial response" because the "cause" is a function of the metabolic needs of an apex predator that is, well, a generalist feeder.
Nor do pelagic sharks render any maternal care.
Accordingly, that is another material reason why "territorial response" theories are unfounded as an exculpatory device, i.e., generally human predation caused by legitimate instances of "territorial response" (e.g., a Brown Bear "defending its cub" or female Nile Crocodile "defending its clutch" from a perceived threat) have a strong correlation to maternal care.
Perhaps it natural for the species with the strongest sense of Kin Selection (i.e., Homo sapiens) to impute "reasons" for behavior that seems inapposite to our own makeup.
Given that there is a much more parsimonious reason for the Blacktip shark's aggressive behavior- that is, the stimulus of freshly speared/struggling fish- corroborates the invalidity of the territorial response theory.
Posted by: drudown | Mar 19, 2014 at 01:28 AM