Thriving Oceans

Coming off the heels of Hope for small sea turtle populations, there is yet another stint of positive ocean conservation news; this time for our cetacean friends.  A new publication in Conservation Biology has actually documented voluntary cooperation by shipping vessels to avoid whale strikes. 

Fin, humpback, right and gray whales have the unfortunate distinction of being the most frequently reported victims of collisions based on historical records.  But whale strikes are not limited to only those species as deaths have been noted for sei, blue and minke whales as well.  However, one particular cetacean stands out above the whale strike crowd with victimhood reaching 2 orders of magnitude above the others.  Perhaps its affinity for urbanized coastal waters around the globe, the endangered North Atlantic right whale is in need of a little shipping compassion. Especially when a 2008 report found that  53% of North Atlantic right whale deaths were attributed to vessel strikes.

To curb the problem, conservation policies have been discussed and even implemented, including the establishment of an ‘area to be avoided.’  In 2007, “The International Maritime Organization adopted the Roseway Basin Area to be avoided on the Scotian Shelf as a voluntary conservation initiative to reduce the risk of lethal vessel strikes to right whales.”  This voluntary area to be avoided went into effect on May 1, 2008 and was designed to be seasonally effective from June 1 to December 31st of each year.  With shipping companies traditionally against the execution  of speed reduction regulations and alteration of shipping lanes (i.e. time is money), the notion of a voluntary avoidance area was definitely a concept that needed confirmation of compliance.

To my surprise, the researchers found:

” Estimates of vessel-operator voluntary compliance ranged from 57% to 87% and stabilized at 71% within the first 5 months of implementation. Our estimates showed an 82% reduction in the risk of lethal vessel strikes to right whales due to vessel-operator compliance. We conclude that the high level of compliance achieved with this voluntary conservation initiative occurred because the area to be avoided was adopted by the International Maritime Organization.”

But the caveat with ocean-going vessels avoiding a conventional shipping lane was that they needed to find a new travel route.  And although the newly adopted course was quite favorable to the right whale, it has the potential to increase fin whale ship strikes by approximately 7%.  The argument, however, is that the fin whale population is 250 times more than that of the endangered North Atlantic right whale, right whales are more abundant than fin whales in the ‘area to be avoided’ , and the ship-strike risk to humpback whales and to sei whales will be reduced by 11% and 74% respectively.

So what does a reduction in ship strikes ultimately mean to the endangered North Atlantic right whale, well it may very well be the difference between recovery and extinction.

“Preventing as few as two female deaths per year would increase the population growth rate to replacement levels that would initiate recovery.  Such prevention is particularly relevant given that contemporary probability estimates of deaths from vessel strikes could be as high as 10 individuals in any given year.”

 

Reference: Vanderlaan, A.S.M., Taggart, C.T.(2009) Efficacy of a Voluntary Area to Be Avoided to Reduce Risk of Lethal Vessel Strikes to Endangered Whales. Conservation Biology

The Salty Scoop, week 3, which is merely a highlight of the previous week’s news and blog posts I found interesting and pertinent to marine life and ocean conservation.  And by all means feel free to add your recommended posts, news, videos and pictures via the comments section.

Palau to create world’s first shark sanctuary (Sept. 25)
“The tiny Pacific nation of Palau is creating the world’s first shark sanctuary, a biological hotspot to protect Great Hammerheads, Leopard Sharks, Oceanic Whitetip Sharks and more than 130 other species fighting extinction in the Pacific Ocean.”

Warming ocean melts Greenland glaciers (Sept. 23)
“With whale fins splashing in the distance, Ruth Curry hauls up her catch from the blustery deck of an icebreaker.  An orange tube fixed to a metal frame breaks the surface as the motorized winch stops groaning. Inside: data on the water temperature deep down in this glacial fjord off southeast Greenland.”

Hunt for clues to sea life deaths at Farallones (Sept. 22)
“A humpback whale that suddenly rose out of the water and splashed down near the Farallon Islands provided a research vessel full of scientists with a surprising bonanza of research data.”

Emperor Penguins -v- Leopard Seals in Antarctica (Sept. 24)
“Emperor Penguins, Aptenodytes forsteri, return from the seas to feed their young. Dramatic scenes unfold as they hesitate at the edge of the Antarctic sea ice after spotting a Leopard Seal, Hydrurga leptonyx, on the prowl under the Antarctic ice. Narrated by the incomparable David Attenborough.”
Posted by GrrlScientist on Living the Scientific Life (Scientist, Interrupted)

EU nations fail to agree on bluefin tuna ban (Sept. 22)
“A sharply divided European Union failed Tuesday to protect the threatened bluefin tuna, as the bloc’s Mediterranean nations refused to back even a temporary a ban on catching the fish prized by sushi aficionados.”

Deep-sea trawling debate heats up in France (Sept. 24)
“French deputies are calling on Jean-Louis Borloo, the country’s minister of ecology, energy, sustainable development and sea, to clarify France’s position on deep-sea trawling in international waters and whether the government intends to support a possible United Nations moratorium.”

This EXCELLENT video says it all!

A new publication in Conservation Biology is shedding light on the effect of a low population on fertility success in sea turtles.  And unlike other species that experience reduced fertility when population densities drop, green sea turtles, loggerhead sea turtles, and their conservationists are receiving a bit of good news. 

“We found that there has been no reduction in fertility in small nesting aggregations in either of these species worldwide.”

The well known issue of sea turtle overexploitation has sparked recovery efforts around the globe.  But the lingering question was whether some turtle populations have passed the point of no return and would thus be unable to ultimately avoid extinction.  According to researchers, marine species have had a variable success rate in recuperating from low numbers, which is a product of the biology of the species and human pressures like habitat degradation and harvesting.  However, these latest findings suggest that even populations comprised of very low densities have a chance at recovery (Previous critical density models indicated depensation might occur when populations dipped below 5% of historical numbers).

“Furthermore, there was clearly no pronounced reduction in fertility in either species at low numbers, even in rookeries yielding as few as 10 clutches per year.”

 

“The capacity to maintain functional levels of fertilization success in the face of high levels of exploitation may help in part to explain why total extirpations have been few and recoveries have been possible.  This information does not, however, explain why in some cases recovery has not occurred.”

I guess the biological moral of the story is that even highly reduced populations have an “intrinsic conservation value”, and can provide much needed information in sea turtle biology and aid in global recovery efforts.

BELL, C., BLUMENTHAL, J., BRODERICK, A., & GODLEY, B. (2009). Investigating Potential for Depensation in Marine Turtles: How Low Can You Go? Conservation Biology DOI: 10.1111/j.1523-1739.2009.01313.x

In honor of International Coastal Cleanup Day 2009!

California Coastal Cleanup Day
Ocean Conservancy’s International Coastal Cleanup

International Coastal Cleanup Day is Sept. 19, 2009 - Marine debris is any man-made, solid material that enters our waterways directly or indirectly. A problem that not only damages our marine and coastal ecosystems, litter that finds its way into the environment affects wildlife as well as beach goers  Nearly 80% of debris, found on beaches, coastal waters, estuaries, and oceans, is washed, blown, or dumped from shore, while 20% is from recreational boats, ships, fishing vessels, and ocean platforms.

Cigarette butts, soda cans, plastic bags, and fishing gear are slow to degrade and present horrific problems to the life they encounter. Studies have shown that marine debris threatens over 265 different species of marine and coastal wildlife through entanglement, smothering, and interference with digestive systems.

Whether a small or large-scale polluter, the litter entering our seas and oceans is reducing fish and wildlife populations.  In fact, the cumulative impact of continuous, small-scale pollution can be dramatic.  The increase in the use of various kinds of plastic as durable, lightweight packaging has heightened the need for proper management and disposal.  Because of the abundance of plastic in our daily lives, it is of no surprise that it is ubiquitous in our world’s oceans.

Besides the threats to wildlife, certain types of marine debris, such as broken glass and medical waste wash-ups, can pose a serious threat to public health.  This type of debris and pollution has resulted in beach closures and swimming advisories that have robbed coastal communities of significant tourism dollars.

So go beach combing this weekend and forget the shells…GET THAT TRASH AND SAVE WILDLIFE!

California Coastal Cleanup Day
Ocean Conservancy’s International Coastal Cleanup