Thriving Oceans

Echinoderms have quite a range of body shapes that include those drawn out with arms like starfish, spherical as displayed by sea urchins, and branched/feathered such as sea lilies.  There are approximately 6000 species in the phylum Echinodermata, many of which are protected by spines.  In the crown of thorns starfish, the poisonous spines protect it from predation as it feeds on coral polyps.

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? 

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. 

Scarids, 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.

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?

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

Humuhumunukunukuapua’a (or reef triggerfish) shows me who’s the ocean boss in just 10 seconds.  Well, boss over this section of a reef in Maui at any rate.  After 10 seconds I decided to leave him in peace to guard his territory.

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…

And 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.

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

Incredible footage from the brief glimpse we’ve been given so far.  Looking forward to exploring Oceans with Disneynature on Earth Day!