Overlooked Species Theatre presents: Pacific Sleeper Shark

One of the great benefits of living so near the ocean is that every once in a while, something really cool washes ashore. Such was the case last week when a resident of Malcolm island found a dead Pacific sleeper shark on her doorstep.


Well, by the time she found it, it actually looked a bit more like this:

(I must warn you that that the pictures don't get any less graphic from here on in)

I had the opportunity to take some measurements and samples for a fisheries scientist who studies sharks. Having never dissected a shark, I soon found it was unlike anything I had ever seen up close before.

It was about nine feet long, though I later found that sleepers can grow to over 14 feet. It also had incredibly thick muscles along the spine for propelling the shark forward with powerful strokes of its tail.

Unlike most groups of fish, sharks have no swim bladders and must swim continuously to keep from sinking. Their skeleton is made entirely of cartilage, which is much lighter than bone. But this is not the only advantage the shark possesses for staying afloat.

Building a case for marine protected areas

Back in January, David Shiffman of the ever insightful Southern Fried Science came out with an interesting post which begged the age-old question 'Can marine protected areas save the ocean?' Actually, the question was more like 'Can no-take areas save fish stocks?' The conclusion he reached was that yes, maybe, in some cases, if everything is done right, it would probably help. Of course, he put it much more eloquently than that and also used this wonderful cartoon, which I have shamelessly reposted (courtesy of NOAA):

Fast forward to the present (well, let's say two weeks ago), and the publication of a paper in PLoS ONE: Large Recovery of Fish Biomass in a No-Take Marine Reserve. 'A paper', you say, 'What gives?' True, I lured you in with the hot fudge sundae of marine humour only to serve you the cold goulash of peer-reviewed literature. But not to worry, I will summarize.

The study took place in Cabo Pulmo National Park, marine reserve on the south-east tip of the Baja California Sur in Mexico. The reserve includes a large 'no-take' area (or 35 % of the total area) that was closed to fishing. The park was surveyed in 1999, four years after it was established, but no significant difference was found between the biomass (the total living mass) of the fish there and and surrounding areas where fishing was permitted. However, the reserve was surveyed again ten years later and this time there was a large difference.

How large, you ask? Over those 10 years the fish biomass in the park had increased 463 %, while there was no significant change in surrounding areas. Not only that, but the biomass of top predators, such as sharks, had increased by an astounding 11 times. In fact it was the largest recovery recorded for any marine reserve in the world!

Tell MSC that a fishery that catches 100,000+ sharks and hundreds of sea turtles is not 'sustainable'

A fishery notorious for its bycatch of sharks and sea turtles is close to snagging something they actually want: a coveted eco-label from the Marine Stewardship Council.

The Atlantic Canada longline swordfish fishery - aka the "fishery for unwanted sharks mostly, and sometimes swordfish, and all too often turtles" - has been recommended for MSC certification by Moody Marine Ltd., a company that conducts assessments for the MSC process.

All is not yet lost, though: the public comment period is open until April 11, and this is your chance to make your voice heard. Your effort can have a real, positive impact for sea turtles and sharks in Atlantic Canada.