Thursday, January 26, 2012

Fishing for Sharks - Lecture!

Warning - tedious!
But I'm sure that Professor Choat is trying his very best - not everybody is as talented as Demian!

Anyway, got some time to spare?
This is about counting Sharks, about their different reproductive strategies and about whether Sharks can be managed, which is a euphemism for fished sustainably without pushing stocks into extinction. You may want to re-read those posts before watching the video. You may also want to prepare a strong mug of coffee!

Choat and his cohorts have amassed an impressive array of data from the four corners of the globe, along with some surprising factoids, like the fact that the Seychellois have long fished intensively for Sharks and exported the meat (!) to Zanzibar. Did you know that?
For the ever too busy, here are the conclusions.
  • Strong evidence that Reef Shark populations are impacted by even moderate levels of fishing. Long-term visual transects are an appropriate tool for monitoring Reef Shark abundances for this purpose
  • Inferred decline in Shark abundances are manifested at a variety of spatial scales from among reef clusters to between ocean basins
  • However evaluation of fishing effects may be confounded by difference in reef structure, size and habitat configuration
  • All shark species appear to be vulnerable to fishing impacts; reef sharks with intermediate size renges, biannual reproduction and low fecundities are especially problematical
  • No refuge in depth!

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