Friday, June 24, 2011

Predation Carcharodon carcharias or Isurus oxyrinchus?

A long beaked dolphin (Delphinus capensis) missing it's middle section in a "very suspect" semi circular pattern washed ashore in Redondo Beach in March this year (click image).

The wound pattern opened up the question about it's attacker(s) and a running debate is now unfolding between two camps who are championing:

1. Carcharodon carcharias

2. Isurus oxyrinchus

“It’s a predation kill, most likely by a great white shark,” Dave Janiger, a curatorial assistant in the mammalogy department of the Los Angeles County Natural History Museum.

The main question is timing. Do we even have Carcharodon carcharias off Redondo beach in March large enough to make a successful predation on an animal this big?

Seals in August and September have washed up in the same location without heads in previous years and that's fits with migration profiles.

So, was this the work of an overlarge Isurus oxyrinchus perhaps?

Image by surf photographer Brad Jacobson.

Viva Honduras for the sharks!

Honduran President Porfirio Lobo Sosa will sign the sanctuary bill into law on Friday on a visit to the island of Roatan, the country’s top diving and snorkeling destination, his office said on Thursday.

The move makes permanent a moratorium on commercial fishing for sharks that Honduras announced last year in a joint declaration with the Micronesian island of Palau.

The march for sharks has reached all corners of the planet, and in the shadow of Mexico's recent ban on shark fishing this brings strong leadership to Latin America.

Guy Harvey Ocean Foundation funds University of Miami's R.J. Dunlap Program

MIAMI – June 23, 2011 -- In the past 50 years, approximately 80 percent of all sharks have disappeared – this includes the shark populations off the coast of the Sunshine State.

The University of Miami's R.J. Dunlap (RJD) Marine Conservation Program was awarded a $30,000 grant by the Guy Harvey Ocean Foundation (GHOF) to conduct research designed to further shark conservation off the Florida coast. The grant has the potential of reaching a total of $120,000 over the next four years.

"The ocean's top predators are under unprecedented pressure from unsustainable fishing practices and changes in the ocean chemistry," said world-renowned marine artist and biologist Dr. Guy Harvey. "This research will give us great insight into how their removal will impact the entire marine ecosystem."

Headed by Dr. Neil Hammerschlag, the RJD Program is investigating the effects on the ecosystem structure due to overfishing top predators. "Models have indicated that a decline in top predators will decrease the number of economically important fishes, and even a loss of important habitats such as coral reefs," according to the proposal.

The team will conduct a series of field and laboratory studies including field surveys, stable isotope analysis, genetic analysis and blood hormone analysis. Taken in marine protected areas and areas subject to fishing throughout the Florida Keys and Dry Tortugas, field studies will be used to determine community structure and patterns.

Press release.