Vol 10, No. 4 [October-December 2012]

Ocean blues

13 Four additions to geopark network
13 20 biosphere reserves join global network
16 Romania to host Chair
16 26 new World Heritage sites
17 China inaugurates STI policy centre
17 Okapi appeal raises nearly US$40,000
18 Coastal erosion from sea-level rise underestimated
18 Prehistoric dentists could fill a cracked tooth

19 Hayat Sindi on blending entrepreneurship with philanthropy

21 Bridging the digital divide
24 All for one and one for all: genetic solidarity in the making
(cet article est disponible en français)

28 Agenda
28 New Releases

Direct link A World of Science Vol 10 N°4 (PDF document)
See also archives for A World of Science.


Bringing fisheries on board

They may not be cute like seals or colourful like clownfish but they play a crucial role in protecting the oceans. Scientists refer to them as ‘keystone species:’ remove them from the top of the food chain and the food web will collapse.

We are referring to sharks, of course. Unlike human fishing techniques, which tend not to discriminate between sick and healthy specimens, sharks are selective: they target weakened prey, thereby keeping fish populations healthy and strengthening the gene pool. By keeping numbers down, they avoid overpopulation around coral reefs.

Even their intimidating behaviour has an ecological purpose. Scientists in Hawaii (USA) discovered that, in the absence of patrolling tiger sharks, turtles overgrazed seagrasses until these were destroyed. When their predator returned, the turtles grazed over a wider area.

The public tends to perceive sharks as man-eaters, yet shark attacks on humans are rare: about 100 are recorded each year, few of them fatal. Humans pose much more of a threat to sharks than the reverse: 17% of more than 1000 assessed shark species are threatened by fishing and bycatch, according to the Red List of the International Union for the Conservation of Nature. The growing popularity of shark’s fin soup has encouraged the cruel practice of ‘shark finning,’ whereby the fins are cut off a live shark which is then left to die in agony. An estimated 26–73 million sharks are killed each year to supply the global shark’s fin market.

Fortunately, there is a growing awareness of the value of sharks for the health of our oceans. A Memorandum of Understanding on the Conservation of Migratory Sharks was concluded in 2010 under the UN Convention on Migratory Species (CMS). Last September, 50 signatory countries adopted a new conservation plan to catalyse regional initiatives. Crucially, industry representatives, NGOs and scientists will be involved in implementing the plan.

International conventions are an essential tool for protecting marine biodiversity, given the lack of physical barriers in the ocean to confine species to a single zone. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) was adopted in 1973, followed by the CMS in 1979 and the Convention on Biological Diversity in 1992. Importantly, these conventions are today working with industry to incite it to adopt more sustainable practices.

A Blueprint for Ocean and Coastal Sustainability provided the third Earth Summit (Rio+20) with valuable input last June, for it traced a roadmap for combining conservation with greening the blue economy. This interagency publication was produced by UNESCO’s Intergovernmental Oceanographic Commission, in conjunction with FAO, IMO and UNDP.

The story beginning overleaf assesses the implications for marine biodiversity of transgressing planetary boundaries, due to human-induced changes to the climate system, pollution and ocean acidification, as well as more direct threats like invasive species, overfishing and habitat destruction. It then outlines a strategy for protecting biodiversity from irreparable harm.

Wendy Watson-Wright
Assistant Director-General and
IOC Executive Secretary

Gretchen Kalonji
Assistant Director-General
for Natural Sciences

Back to top