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Archive for the ‘Fish’ Category

Declining Parrotfish Instill Hope but Highlight Human Flaw

Posted by Mola2mola On December - 1 - 2009

While rummaging through the latest research in Conservation Biology, I came across a publication that caught my attention.   It’s not that the title conveyed a trinket of enlightenment nor promised to do so as I wound my way from introduction to methods to discussion.  In fact, the title evoked an emotional response that was the exact opposite of astonishment.  And by that I merely mean I could (or assumed I could) foresee the results, which is practically a staple in the ocean conservation world when discussing the effects of a burgeoning coastal human population on neighboring marine ecosystems.  In that context, is there anything else that should pop to mind other than overfishing and declining fisheries? 

Credit: Richard Ling

But, I will admit that my curiosity was peeked as it is my first encounter with parrotfish headlining the research.  So, I decided to move forward and examine the text behind the title, “Implications of Urbanization for Artisanal Parrotfish Fisheries in the Western Solomon Islands.”  Perhaps the title’s key words like ‘urbanization’ and ‘fisheries’ are dead giveaways, but remember this is a scientific publication and not the latest thriller in the midst of protecting a multi-level plot twist for the sake of sparking revenue.

With the pages rolling it becomes quite apparent that there are a few conservation gems sprinkled throughout the paper and worthy of rehashing, or what a waste of my time in writing and yours in reading this post.   Success of marine protected areas, declining species, and the interconnectedness of species in an ecosystem are the themes/take home messages while the family Scaridae is the star, or victims, of the show. 

neg_quoteScarids, or parrotfish, included 83 species at the time of my university courses (~90 species as of 2002) and are so named because their fused teeth resemble a parrot-like beak.  And it is this beak that is quite useful for biting off pieces of coral and algal fronds.  The bits are ground down in their massive pharyngeal mills and the algal cells are extracted.  As discussed by the authors, parrotfish fill a critical role in maintaining coral reef systems by controlling filamentous algae and Scleractinian corals, removing detritus, and digging through the surface of the reef thusly redistributing the ground calcareous pieces as sediment.

As Pacific Island populations grow, the demand for coral reef resources including the parrotfishes themselves increases dramatically.  Thus, it is not surprising that the fishing pressures have caused a total parrotfish population decline of 45% from 2004 to 2005 in the Pacific Island study area. But remember I said there were a few conservation gems…well it turns out communities in the Western Solomon Islands have begun to see the frightening trends and instituted management practices and community-based marine protected areas to curb the overfishing (and habitat degradation) problem.  Not only are their livelihoods on the line but the whole coral reef system.

The take home lesson is that community-based marine protected areas do in fact work, and is evident with the following results:

 -Parrotfish numbers/abundance in outside sites were significantly lower than inside community-based marine protected areas (CBMPA) for each size category.

-Large effects between inside and outside CBMPAs were evident in each size category.

-Combined, these findings reinforce the stark difference in abundance across fish size categories between inside and outside the CBMPAs of villages with customary management and an urbanized center.

Photo: Richard Ling

We now have yet another piece of evidence highlighting the need for marine protected areas to ensure healthy fish populations and coral reefs, as well as a need to conserve for the future health of a growing human population.  However, instilling good ocean management practices is not and an idea we can afford to treat with procrastination.  According to the authors, “There is a negative correlation between effective conservation and human population size (beyond a threshold of more than 1000 people) and between market integration and wealth, which suggests that as rural communities urbanize and monetize in Melanesia, their capacity to conserve resources weakens.”

And this negative correlation is perhaps the most interesting finding and something that sounds quite familiar.  As populations grow and become more economically viable they effectively lose their ecological self-control and ocean husbandry suffers. 

So is this humankind’s innate progression as we become less reliant on the natural course of the environment and aim to control it?  I have definitely seen this trend before…Have you?

This post was chosen as an Editor's Selection for ResearchBlogging.org
ASWANI, S., & SABETIAN, A. (2009). Implications of Urbanization for Artisanal Parrotfish Fisheries in the Western Solomon Islands Conservation Biology DOI: 10.1111/j.1523-1739.2009.01377.x
Photo credits: Richard Ling

Sashimi may be an endangered species

Posted by Mola2mola On November - 20 - 2009

I’ve been a bit distracted in the last couple of weeks and hence a lackluster post performance.  So time to get back to the ocean nitty gritty…

SashimiAnd what better way to start anew than with something to ease our appetites.  As I glance over the virtual menu I decide what the hell, “Waiter, I’ll take the tuna.”  I know I railed against overfishing, reported on the decreasing numbers of tuna, and have heard conservation organizations ask me to stay away from bluefin but no worries as the menu indicates nothing about item #13 being southern bluefin.  Oops, I guess he didn’t hear me, “WAITER, I’LL TAKE #13, THE CRITICALLY ENDANGERED TUNA…PLEASE.”

Yep, you heard it right that time.  A new study published Wednesday (Nov. 18) in PLoS has found that piece of tuna you just ordered and most likely eaten was potentially an endangered species.  And if I actually ate tuna sushi, that would be enough to make me sicker than ingesting a helping of week old sashimi leftovers.

Now that we know I’m safe from feelings of guilt and a potential bout of food poisoning, I’ll move on with the findings.  With a background in molecular biology, I love it when genetics rears its head in the world of conservation.  In this particular case, the researchers collected tuna samples from restaurants over a 7 month period in 2008 and, for the sake of brevity, used the obtained DNA to identify the species.  Here is a summary of their results:

-A piece of tuna sushi has the potential to be an endangered species, a fraud, or a health hazard. All three of these cases were uncovered in this study. Nineteen (out of 31) restaurant establishments were unable to clarify or misrepresented what species they sold.

-Twenty-two of 68 samples were sold as species that were contradicted by molecular identification, while six samples were sold as ‘‘tuna’’ or ‘‘red tuna.’’ 

-Five out of nine samples sold as a variant of ‘‘white tuna’’ were not albacore (T. alalunga), but escolar (Lepidocybium flavorunneum), a gempylid species banned for sale in Italy and Japan due to health concerns.

-Nineteen samples were northern bluefin tuna (T. thynnus) or the critically endangered southern bluefin tuna (T. maccoyii), though nine restaurants that sold these species did not state these species on their menus.

The high stakes, money making tuna market has effectively become a game of chance for the consumer. And when you can’t trust the restaurant, the menu, or the staff, perhaps it is better to err on the side of caution.  Just something to think about the next time you pick up your chop sticks.

ResearchBlogging.org
Lowenstein, J., Amato, G., & Kolokotronis, S. (2009). The Real maccoyii: Identifying Tuna Sushi with DNA Barcodes – Contrasting Characteristic Attributes and Genetic Distances PLoS ONE, 4 (11) DOI: 10.1371/journal.pone.0007866

A Seahorse Photo Session

Posted by Mola2mola On October - 22 - 2009

Let’s send out some positive ocean vibes and get a jump on the weekend with a photo session of one of my favorite sea creatures…Seahorses!

Seahorses belong to the genus Hippocampus which includes more than 47 species.  Showcasing a multitude of colors and sizes, they  are adept at camouflaging themselves amongst seagrasses, coral reefs and mangroves in the shallow tropical and temperate waters throughout the world.  And for those keeping track the Leafy Sea Dragon rounding up the session belongs to the genus Phycodurus, but but nonetheless is still a seahorse relative…

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Atlantic Bluefin Tuna in Serious Trouble

Posted by Mola2mola On October - 15 - 2009

 “The United States today announced that it will seek the strongest possible management for the conservation of Atlantic bluefin tuna, a fish which is in serious trouble.

This action has two components.

Atlantic Bluefin TunaFirst, we are sending a clear and definitive statement to the international community that the status quo is not acceptable. 

Over the past 40 years, the international body that manages bluefin tuna, the International Commission for the Conservation of Atlantic Tunas (ICCAT), has overseen a 72 percent decline in the adult population of the eastern Atlantic and Mediterranean stock of bluefin tuna and an 82 percent decline in the adult population of the western Atlantic stock. 

In recent years, the countries that fish the eastern stock, which spawns in the Mediterranean, have done so at two to three times the sustainable level, causing a significant and rapid decline in the last decade. The status of the western stock, which spawns in the Gulf of Mexico and is fished primarily off the North American coast, has recently stabilized due to the establishment of well-enforced, science-based quotas. 

A sustained lack of science-based management for the eastern Atlantic and Mediterranean stock of bluefin tuna, and concerns about slow recovery in the west, have brought us to this point. As a member in ICCAT, the United States calls for strong and definitive action at the November 2009 meeting in Brazil. This includes establishing management measures that end overfishing such as setting responsible science-based quotas, stronger enforcement of these quotas, and closures during spawning periods. 

Second, the United States strongly supports Monaco’s proposal to list Atlantic bluefin tuna under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to prohibit international trade of the species. The United States will consider amending or withdrawing support for the Monaco proposal if ICCAT adopts significantly strengthened management and compliance measures. 

Improving international fishery management and ending illegal, unreported and unregulated fishing are high priorities for the United States government, Congress, commercial and recreational fishermen, and conservationists.”

-Statement from Dr. Jane Lubchenco, Under Secretary of Commerce for Oceans and Atmosphere and NOAA Administrator, Announcing Support for Listing Atlantic Bluefin Tuna on International Trade Endangered Species List


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