Up from the Deep: Monsters and Trawlers
January 29th, 2007
The BBC recently linked to footage from Japan of a prehistoric shark which is rarely seen due to its usual habitat of 600m deep. Since few submarines can make it to these depths, it’s not suprising that little is known about the species. By dating fossils of the animals’ unique three-pronged teeth, however, scientists have been able to determine the frilled shark to be around 18 million years old.
Oceanographer and former NOAA chief scientist Sylvia Earle claims the most bio-diverse region in the world is not the rainforest but in fact the deep ocean. This concept does not stop fishermen from killing the frilled shark, and most other sea life, when they are trawling for other catch, essentially dragging huge swathes of net by boat. Scientists have likened the practice to bulldozing a forest to catch a few deer, a practice that’s surely not sustainable if fishermen want to continue with their profession.
Of course you can also think, like the Japanese man in the video, that “the fish is just weird.”
Link to BBC World News video
Link to Frilled shark stats on Fishbase.com
January 24th, 2007 at 6:07 pm
I thought this shark was caught by “marine park staff”? (according to CNN/Reuters: http://www.cnn.com/2007/TECH/science/01/24/shark.japan.reut/index.html )
But you make a good point. Few would disagree with you that bottom trawling is bad news for life on the sea floor. And that “bulldozing a forest” analogy isn’t far off. More like bulldozing a rare, old-growth forest. Deep-water sponges and corals (not the tropical pretty ones you know; more like the polished jewelry kind your mom wears) are generally VERY slow growing.
The UN toyed with a major int’l ban on bottom trawling, but it didn’t pass (see http://news.bbc.co.uk/2/hi/science/nature/6181396.stm ). These bans are actually supported by several fishing groups, realizing the practice is self-limiting (destroying fish habitat ruins fish populations).
Sylvia Earle said that? Deep ocean habitats are generally regarded as being species-poor when compared to other marine systems (e.g. tropical coral reefs). That’s biodiversity in terms of straight # of species (“species richness”). I’d be interested in hearing her reasoning. Maybe comparing deep ocean “seamounts” vs. open water?
This isn’t to say deep ocean habitats aren’t important (ecologically, economically, aesthetically, etc.) and worth protecting. They are.
Side note: funny that fishing fleets can reach these deep (REALLY deep) habitats simply by lowering nets, but scientists need to pay big bucks to send little robot-submarines down to study them. The Monterey Bay Aquarium’s research arm (MBARI) has a few engineering internships: http://www.mbari.org/education/internship/07interns/07announce.htm
January 31st, 2007 at 2:28 am
And I stand corrected. According to some accounts, species diversity is surprisingly high in deep-sea communities, although this varies greatly with location and depth. And diversity aside, it’s still a unique and pretty neat system.
This raises an interesting point.
Q1) What’s so special about biodiversity anyways? And why is it worth saving?
A1) Start with http://en.wikipedia.org/wiki/Biodiversity#Benefits_of_biodiversity
(although I have some gripes with Wikipedia; peer-review is only as good as the quality of the “peers.”)
Also check out “The Future of Life” by E.O. Wilson. Not a hippy-treehugger or science-dork book. Nice reasoning from a VERY well respected biologist.
Q2) Ok, deep-sea communities, coral reefs, rainforests are all neat yada yada. Does that mean “species-poor” systems aren’t worth saving?
A2) Biodiversity isn’t everything. See also:
http://en.wikipedia.org/wiki/Ecosystem_services
For example: coastal salt marshes (or “wetlands”, “sloughs”, etc.) are rather species-poor compared to some other systems. But they offer important “services” to humans like flood control, filtering water pollutants, nursery grounds for birds and commercially-important fish, etc.
April 2nd, 2010 at 1:00 pm
Excellent post. If you would like to listen to BBC Radio on the iPhone – I strongly recommend BBC Streams – it is easily the quickest and most reliable way to listen to BBC Radio on the iPhone, iPad or iPod Touch and it’s free at BBCStreams.com.