Celebrating Bio-Diversity Day: It’s Not A ‘Wake’ Yet

Finless-Porpoise, about air pollutionCompiled by Newsbyrd staff-

(May 22, 2012)  On December 29th 1993, at the United Nations Conference on Environment and Development held in Rio, 172 governments ratified a motion creating International Day for Biological Diversity, to be observed each year, on that day.

In 2001, and due to holiday conflicts, it was decided by the newly-dubbed “Rio Earth Summit” to change the date to May 22nd.

The focus of this year’s world celebrated event is Marine Biodiversity; two words we hope will not become an oxymoron in the future.

Bluefin Tuna

This week MEPs will vote on measures that include further reducing fishing quotas and strengthening controls over bluefin tuna fishing in the eastern Atlantic and the Mediterranean. Spanish Green MEP Raül Romeva i Rueda says tuna sanctuaries could be the answer in his report to be debated on 22 May and voted on the day after.

Over the past 50 years, the Bluefin fisheries have been overfished to less than 10 percent of its previous numbers.

In a new draft resolution, the Parliament aims to tighten rules protecting EU bluefin tuna stocks, along the lines proposed by the International Commission for the Conservation of Atlantic Tuna (ICCAT).

The proposals include reducing the allowable quotas from 13,500 to 12,900 tons a year and strengthening control measures used to implement the recovery plan of tuna population.

Another proposal in the report is the establishment of sanctuaries. Mr Romeva i Rueda calls for some zones in the Mediterranean to be declared closed areas or sanctuaries for bluefin tuna during the spawning season.

Atlantic Cod Show Signs of Recovery

To balance this post and in the search for some positive ocean-environment news, we found this piece in Science Magazine about the recovery of Atlantic Cod off the coast of Nova Scotia. The bad news being that it was hard to find.

Comebacks. Sports teams and aging rockers have them. Fish rarely do. But in a bit of good news for fisheries scientists, one ecosystem devastated by overfishing off the coast of Nova Scotia is showing early signs of recovery, a new study suggests. Here, Atlantic cod and other predatory fish, whose numbers nosedived in the early 1990s, seem to be struggling back, pointing to the resilience of marine communities, researchers say.

This is an excellent article, not only about fishing limits but also about the interaction of species under stress.  Read More…

Sharks in Decline

One of the best ways to determine how many fish are out there, is to go fishing.  Although this may sound like a rather simplistic approach to a very complex question, it works. It’s called a fisheries-dependent population survey.

One of the most widely circulated examples of such a survey where sharks are concerned, came from Dr. Julia Baum. Her group analyzed data from the United States swordfish and tuna long-line fleet, which often catches sharks.  In a 14-year span from 1986 to 2000, over 200,000 longlines were set in the Northwest Atlantic Ocean, recording the number of sharks of various species caught during each deployment.  Dr. Baum’s research was calculated from this data.

Her results were revealed in her research paper, Collapse and Conservation of Shark Populations in the Northwest Atlantic, which has been cited more than any other paper of its kind.  Since 1986, Dr. Baum’s analysis of logbook data reveals an “across the board” decline in the population of all shark species: These include a 89% decline in hammerhead sharks, 70% for mako sharks, 79% in great white sharks, 80% in thresher sharks , 65% in tiger sharks and a 60% decline for the blue sharks.

The Panda Bear’s Marine Counterpart, China’s Finless Porpoise

By John R. Platt  (May 19, 2012)  Chinese officials added an extra 50,000 carp to the waters of Poyang Lake this week to help feed the endangered Yangtze finless porpoises that live there, according to a report from the Xinhua news agency.

Around 300 to 500 porpoises live in Poyang Lake in northern Jiangxi Province, representing between one third and one half of the subspecies’s global population. The porpoises have experienced a dramatic population crash in recent years, falling from 2,700 individuals in 1991 to around 1,000 in 2011.

Things haven’t gotten any better this year: Six dead porpoises have been found in Poyang Lake, and another 12 dead, including a pregnant female, have been found in Dongting Lake in northeastern Hunan Province. A survey earlier this year found only 65 porpoises in Dongting, so the deaths are a terrible blow for that tiny population. Xinhua reports that at least five more dead porpoises turned up in the Yangtze River, which connects the two lakes, putting the death toll above 20, but a report from the World Wide Fund for Nature puts the total fatalities much higher at 32 porpoises.

Experts blamed the spate of deaths on pollution as well as low water levels due to drought and climate change. Other theories include disease or damage from electrified fishing nets. Many of the dead porpoises showed signs of starvation, which may have influenced China’s decision to stock Poyang with extra fish. At least one of the dead mammals from Dongting had been severely injured by a boat propeller.

Finless porpoises—so named because have low ridges on their backs instead of full dorsal fins—can also be found in the coastal waters off Japan, Indonesia and Korea, but the Yangtze variety are the only ones that live in freshwater. The adults of all finless porpoise varieties grow to about 1.5 meters in length, compared with up to 1.9 meters for their more famous cousins, harbor porpoises (Phocoena phocoena).

Poyang used to be China’s largest freshwater lake. The construction of Three Gorges Dam and subsequent droughts have reduced it in size by nearly 95 percent and weakened the region’s ecology.

Source: Scientific American

Feature photo: A captive and related Japanese finless porpoise at the Miyajima Aquarium in Japan.

 

 

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Posted by at May 22, 2012
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