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Archive for the ‘Bycatch’ Category

My sea turtle hazard is worse than your sea turtle hazard

Posted by Scott A. On June - 24 - 2010

This post was chosen as an Editor's Selection for ResearchBlogging.org
My sea turtle hazard is worse than your sea turtle hazard. 

Of course.  

Sounds logical. 

And more importantly it falls within that quirky social dynamic called HUMAN NATURE.  But the results of bias within the scientific community is an interesting topic; especially when you add the sea turtle variable and the number of threats plaguing the seven species.  So put any preconceived notions that you may have aside and let’s see if we can all come together and accept the fact that the hazard I’m researching poses the greatest threat to sea turtles.

Well, perhaps we should turn to the experts and listen to what they have to say.  And that’s exactly what the authors of a new publication, Using Expert Opinion Surveys to Rank Threats to Endangered Species: A Case Study with Sea Turtles, in Conservation Biology did.  And should we really be surprised by the findings?

An internet-based survey was distributed to sea turtle experts that was designed to determine the respondents’ overall experience, expertise and the proficiency in regards to particular species, geographic regions, and hazards.   Hazards that included pathogens, direct take, global warming, nest predation, pollution, coastal development, and fisheries bycatch.  After quantifying results spanning the nonprofit sector, government agencies, and respondents in over 100 counties, a pattern began to emerge.  A pattern attributed to expert bias.

“Respondents with no experience with respect to a sea turtle species tended to rank hazards affecting that species higher than respondents with experience.  A more-striking pattern was with hazard-based expertise: the more experience a respondent had with a specific hazard, the higher the respondent scored the impact of that hazard on sea turtle populations.” 

Perhaps a sign of the times, everyone was in agreement that sea turtles were under threat from multiple anthropogenic hazards.   It also became apparent that there was an overall consensus on the greatest hazard, fisheries bycatch.  The survey found:

  • Bycatch was ranked as the top hazard for 18 sea turtle populations.
  • Coastal development was ranked as the top hazard for six populations.
  • Nest predation was the top hazard for three populations.

Interesting!  And I guess that exclamation warrants further development if I expect it to make any sense.  Although bycatch, a pelagic threat, ranked as a top hazard for 18 populations, a disparity still exists between coastal development and nest predation, which are terrestrial and coastal threats.  The amount of invested resources does not correspond to the highly scored pelagic threat. 

The authors point out that, “Twenty-eight percent of survey respondents reported conducting research or activities focused in the pelagic environment, compared with 70% who conducted research in both terrestrial and coastal environments.”

Which rounds off the discussion as to its applicability to conservation.  Should statistical methods that account for expert bias be implemented by conservation planning programs?  And should hazards that are both highly scored by experts and have a high uncertainty in regards to the range of effect on a population be treated as a research priority?

 Well one thing is for certain and I agree completely with the authors that, “Priority setting for the conservation of threatened and endangered species cannot wait for exhaustive empirical research.”


ResearchBlogging.org
DONLAN, C., WINGFIELD, D., CROWDER, L., & WILCOX, C. (2010). Using Expert Opinion Surveys to Rank Threats to Endangered Species: A Case Study with Sea Turtles Conservation Biology DOI: 10.1111/j.1523-1739.2010.01541.x

Bycatch Claims Sea Turtles By the Millions

Posted by Scott A. On May - 18 - 2010

This post was chosen as an Editor's Selection for ResearchBlogging.org
It’s an article packed full of potential contention as it speaks to a variety of issues involving fisheries management.  So thank God we are dealing with a charismatic marine species or we just may be contemplating their extinction.  But then again, perhaps we are doing just that since all 7 species of marine turtles are listed under the Endangered Species Act.  So what does that mean when millions of sea  turtles are caught as bycatch in just 18 years?  I think it means the status quo is definitely due for an overhaul to say the least.

Leatherback Turtle caught on longlineBycatch.  It’s a word that sounds rather innocuous as it rolls off the tongue, but clearly does not do justice to the staggering amount of life that is instantly converted to simple biological waste.  It’s a problem that amounts to tonnes, in the neighborhood of several million per year.  And again I say thank God because the widely popular sea turtle may be able to help shine the light on an ever growing problem responsible for population declines in multiple species.  Well, at least I hope so.

In Global Patterns of Marine Turtle Bycatch, gillnets, longlines, and trawl fisheries are providing us with a perspective that we would probably rather ignore.  Unfortunately the out of sight out of mind attitude is not helping the sea turtle situation and it reminds me of an old mantra I used, “The catch of the day may cost more than you think.”  In this scenario, that cost is…

The total reported global marine turtle bycatch (1990-2008) was ∼85,000 turtles, but due to the small percentage of fishing effort observed and reported (typically <1% of total fleets), and to a global lack of bycatch information from small-scale fisheries, this likely underestimates the true total by at least two orders of magnitude.

turtle-bycatchAnd after looking at the data I am left wondering how many sea turtles are actually killed or die as a result of wounds incurred by coming into contact with gillnets, longlines and trawls.  I can imagine it is only palatable when wearing a pair of rose colored glasses.  But as far as the research goes, there was insufficient data to incorporate mortality rates.

The study found the bycatch per unit effort (BPUE) varied greatly depending upon the region and fishing method employed.  In fact , it identified certain hotspots that are a cause for concern and highlight the need for fisheries management intervention.

Based on reported sea turtle bycatch, the maximum BPUEs found for each fishing method are as follows:

  • 2.2 turtles per set for gillnets in the Mediterranean Sea
  • 19.3 turtles per 1,000 hooks for longlines in the eastern Pacific Ocean
  • 7.2 turtles per haul for trawls in the southwest Atlantic Ocean

Loggerhead Bycatch“Targeted action to reduce turtle-gear interactions is essential for population persistence, and is already underway for some fleets…our study revealed that reports of longline bycatch are two-fold more common than reports of bycatch in either trawls or gillnets.”

Having the data means we have no more excuses for not developing, continuing to develop and implementing a conservation plan that is both regional and fishing gear specific.  The plan must be more than focusing on turtle excluder devices, but must include other innovative management techniques on the lines of time-area closures, etc.  And since time is of the essence and marine turtle populations are at risk, immediate action is required.

ResearchBlogging.org
Wallace, B., Lewison, R., McDonald, S., McDonald, R., Kot, C., Kelez, S., Bjorkland, R., Finkbeiner, E., Helmbrecht, S., & Crowder, L. (2010). Global patterns of marine turtle bycatch Conservation Letters DOI: 10.1111/j.1755-263X.2010.00105.x

Press Release from Sea Turtle Restoration Project  (Nov. 5, 2009)-

Green Sea Turtle Trawler BycatchSea turtle advocates in California and family shrimp fishers from Florida filed a federal lawsuit today against the U. S. State Department for violations of the Endangered Species Act (ESA) for allowing shrimp caught in ways that are deadly to sea turtles to be sold in the United States  The lawsuit filed by the Environmental Law Clinic at Stanford Law School (Palo Alto, CA) on behalf of Turtle Island Restoration Network (Forest Knolls, CA) and the Mayport Village Association (Mayport, FL) claims that the U. S. State Department has failed to properly evaluate and prevent harm to sea turtles from overseas shrimp fleets that sell shrimp to the United States under the ESA’s Turtle-Shrimp Law (Pub. L. 101-162 § 609). It was filed in the U. S. District Court, Northern District of California. See the complaint.

“This is not only a tragedy for sea turtles, which die by the tens of thousands in shrimp nets every year, but is unfair to the U.S. fishers who obey the law and must compete in the U.S. marketplace with shrimp imports,” said Todd Steiner, biologist and executive director of Turtle Island Restoration Network a non-profit organization dedicated to the conservation of sea turtles and their habitat.

“Our Mayport shrimpers are struggling to survive, while foreign fleets get a free pass on the law and flood the market with cheap shrimp,” said Al Millar, representing Mayport Village Civic Association and its small fleet of family shrimpers based in the historic village of Mayport, FL. See www.SaveMayportVillage.net. “We work hard to fish and protect sea turtles but don’t get a break from our own government.”

The lawsuit claims that the State Department has not properly enforced requirements for foreign shrimp vessels to use nets with Turtle Excluder Devices as U. S. fishers are required to do. The lawsuit asks that the foreign shrimp certification process be given additional environmental oversight and review. Recently, shrimp imports from Costa Rica were banned due to failure to protect sea turtles after environmentalists’ complaints, but 15 other nations were certified with little, if any, scrutiny.

“There is a simple, inexpensive, and elegant solution that allows sea turtles to escape drowning in shrimp nets, called a turtle excluder device or TED” said Deborah Sivas, Stanford Law professor, and director of the Environmental Law Clinic, who filed the lawsuit.  “If the State Department can create a reasonable certification program, we can save the lives of thousands of endangered sea turtles while allowing shrimp harvesting to continue.”

Americans consume over 500,000 tons of shrimp annually, and is the top fishery import of the United States, valued at over $3.9 billion last year, according to government figures. This includes trawl-caught wild shrimp and farmed shrimp (which does not capture sea turtles but is environmentally harmful due to pollution of fish ponds and land clearing). About 90 percent of shrimp eaten in the U. S. is imported. See latest U. S. shrimp import data.

Background:
The U. S. Turtle-Shrimp Law was challenged by nations at the World Trade Organization (WTO), claiming to be a violation of the “free-trade” agreement, leading to the famous “Battle of Seattle” protests in 1999 where thousands marched peacefully to protest weak environmental protections in the global trade treaty.  The U.S. Turtle-Shrimp Law was eventually found to comply with the WTO, but poor enforcement has allowed sea turtles around the world to drown in shrimp nets and slide toward extinction. (The movie Battle of Seattle starring Woody Harrelson that dramatized the protests was released in 2008). Read more .

On May 1, 2009, the Department of State certified, pursuant to Section 609 of Public Law 101-162 (”Section 609”), that 15 nations have adopted programs to reduce the incidental capture of sea turtles in their shrimp fisheries comparable to the program in effect in the United States. Belize, Colombia, Ecuador, El Salvador, Guatemala, Guyana, Honduras, Madagascar, Mexico, Nicaragua, Nigeria, Pakistan, Panama, Suriname, and Venezuela. The Department also certified that the fishing environments in 24 other countries and one economy, Hong Kong, do not pose a threat of the incidental taking of sea turtles protected under Section 609. Read more. 

King Salmon Vanish

Posted by Scott A. On August - 17 - 2009

As the weekend rolled to an end and the inevitable Monday workday loom overhead, I moseyed on to the bedroom and turned on the radio. Expecting to encounter a little paranormal lullaby, I was incredibly surprised to find the guest host of Coast To Coast AM, George Knapp, tackling the overfishing crisis.  In his interviews with Rupert Murray (The End of the Line) and Rick Moonen (RM Seafood), George brought this important topic of conservation concern to an international audience.  Since Coast to Coast AM is broadcast on over 500 United States affiliates alone, I was elated  to hear the notion of sustainable seafood practices being promoted to millions and perhaps recruiting some listeners to ultimately make informed and responsible meal decisions.

 And sprinkled throughout their conversations was a discussion, or warning if you will, about a vanishing act recently perpetrated by Alaskan King salmon.  Well, after a little online digging I managed to come up with an AP report (Aug. 2, 2009) on CBS News describing the failure of king salmon to return to a number of Alaskan rivers…again.King Salmon

“One Alaska river after another has been closed to king fishing this summer because significant numbers of fish failed to return to spawn. The dismally weak return follows weak runs last summer and poor runs in 2007, which also resulted in emergency fishing closures.” AP

And as the salmon continue to vanish from our waters year after year, we are left speculating whether the problem is ocean currents, food availability, bycatch, aquaculture, or overfishing.  Yet over the last decade, ” the incidental number of king salmon caught has skyrocketed, reaching over 120,000 kings in 2007.” AP

Hmmm!  Perhaps a connection?  Instead of embarking on another version of the blame game and debating whether (or to what degree) the lack of salmon returns is caused by natural phenomena, such as changing ocean currents, river conditions or available prey, or human activities, we need to institute a little fisheries management tough love. 

For in the end bycatch may not be the only culprit, but as opposed to the actions of Mother Nature, it is the factor that we can definitely control.  And of the 120,000 kings killed in pollock trawl nets in 2007, an estimated 78,000 adults would have returned to the rivers of western Alaska.

AP Article: King Salmon Failing to Return to Spawn

8 Scientific Questions for Preserving Marine Ecosystems

Posted by Scott A. On June - 2 - 2009

Intertwined amongst the scientific publications in latest Journal of the Society for Conservation Biology is an essay harboring questions aimed at current environmental themes such as species management , climate change, and terrestrial ecosystems. The idea behind the essay, One Hundred Questions of Importance to the Conservation of Global Biological Diversity, is to evoke thoughts that will ultimately drive solutions for conservation practice and policy…in short protect biodiversity in the long-term.

And of the 100 most critical questions, 8 were organized under the section of Marine Ecosystem and are as follow:

  • How will ocean acidification affect marine biodiversity and ecosystem function, and what measures could mitigate these effects?
  • What are the ecological, social, and economic impacts resulting from the expansion of freshwater and marine aquaculture?
  • Which management actions are most effective for ensuring the long-term survival of coral reefs in response to the combined impacts of climate change and other existing stressors?
  • Which management approaches to fisheries are most effective at mitigating the impacts of fish extraction and fishing gear on nontarget species and their habitats?
  • How does the effectiveness of marine protected areas vary with biological, physical, and social factors and with connectivity to other protected areas?
  • What will be the impacts of climate change on phytoplankton and oceanic productivity, and what will be the feedbacks of these impacts on the climate?
  • How will multiple stressors, especially fishing, pollution, sea temperature fluctuations, acidification, and diseases, interact to affect marine ecosystems?
  • Which mechanisms are most effective at conserving biodiversity in ocean areas occurring outside the legal jurisdiction of any single country?

I anticipated an addressing of bycatch, climate change, and overfishing, but what I found most intriguing is the all encompassing question of the affect of multiple stressors on marine ecosystems.  This is akin to the model for the theory of everything as such an answer is the universal question.  The marine ecosystems are not defined by a single species or environmental threat, but are an interconnected world in which pollution, overfishing, bycatch, and declining biodiversity culminate in a determination of the state of our oceans.   The more stressors we continue to add to the list, the more difficulty we will have in maintaining healthy oceans.

The decline and fall of Mediterranean sharks

Posted by Scott A. On May - 12 - 2009

I came across a piece on Fish & Aquatic News this past Sunday in which authorities in Spain confiscated 11 tons of shark fins.  It simply reminded me that the Mediterranean Sea is a poster child for overfishing and already at the mercy of an irresponsible tuna industry. Yet, what I did not fully realize was that there has been an incredible decline in sharks over the last 200 years in this region alone.
In a 2008 publication in Conservation Biology, it was found that:

“Only 5 of the 20 large predatory sharks were detected at levels of abundance sufficient for analysis. Moreover, these 5 species showed rates of decline from >96 to >99.99%, which may classify them as critically endangered according to IUCN criteria.”

Even more disturbing is that the authors contend the depleted numbers may mean the large sharks are “functionally extinct” in the Northwestern Mediterranean. So, continued harvesting of sharks only for their fins is adding insult to injury on these cartilaginous ocean inhabitants.

After a rudimentary investigation on Spain’s fishing practices, I found that most of their longlines are actually set on the Atlantic ocean side, which may be compounding the dwindling Mediterranean shark populations. Because overharvesting (i.e. 11 tons of shark fins) is taking place, we are effectively limiting the ability for Atlantic and Mediterranean sharks to replenish falling populations and/or exchange individuals via the “critical migration corridor” in the Strait of Gibraltar.

With up to 2000+ pelagic longlining boats traversing the Mediterranean Sea, a considerable illegal fisheries industry continuing operations, and lackluster regulatory action, top predators responsible for structuring  ocean communities will continue to be at under threat of extinction.

photo credit: Erik Charlton

Reference:

Loss of Large Predatory Sharks from the Mediterranean Sea, Conservation Biology
Volume 22, Issue 4, Date: August 2008, Pages: 952-964


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