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Sea Around Us project newsletter, issue 61, September/October 2010 Bailey, Megan; Sea Around Us Project Sep 30, 2010

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Sea Around UsThe Sea Around Us Project NewsletterIssue 61 – September/October 2010Understanding impacts ofthe Gulf of Mexico oil spill:How will fisheries fare?by Ashley McCrea-StrubContinued on page 2 - Gulf fisheriesAs devastating images of oil in the Gulfof Mexico streamed across virtuallyevery media outlet during the monthsfollowing the explosion of the DeepwaterHorizon on April 20th, 2010, many experts inthe fields of marine ecology and fisheriesscience have found themselves faced withthe question,  “What will be the impacts ofthis disaster?”  As a native of South Floridawith memories of family vacations to Gulf-coast beaches and an appreciation fordelicious Gulf seafood, I have been eager toparticipate in any efforts to better understandthe problem.Attempting to answer this question is nosimple task.  Estimates of the quantity of oil,natural gas and associated methane, andchemical dispersants released into the Gulfof Mexico are plagued by uncertainty.  TheU.S. government-appointed team ofscientists, a.k.a. the Flow Rate TechnicalGroup, estimated that a total of 4.9 millionbarrels of oilwere releasedfrom BP’sMacondo well[1] while anindependentstudysuggestedbetween 4.16and 6.24million barrels[2].  AccordingtoBP’s records,approximately1.8 milliongallons (i.e., about 6.8 million litres) ofdispersant were applied at the site of theleak as well as the sea surface, though thevalidity of this amount has been questioned[3].  Complex oceanographic processeshave made it extremely difficult todetermine the current and futuredistribution of these toxic substances fromthe surface to the sea floor, and the durationof their persistence in the marineenvironment.  Most importantly, there areno immediate answers to questionsconcerning short- and long-term impacts onhabitats and marine organisms in the pathof this disaster.  This uncertainty isparticularly troubling for fisheriesdependent on economically valuablespecies.Despite the geographic distance separatingthe Fisheries Centre from the Gulf ofMexico, the databases developed by theFigure 1. Satellite image from July 28, 2010 demonstrating extent of oil on seasurface. (www.skytruth.org).Page 2Sea Around Us – September/October 2010The Sea Around Us project newsletter ispublished by the  Fisheries Centre at theUniversity of BritishColumbia. Six issues ofthis newsletter arepublished annually.Subscriptions arefree of charge.Our mailingaddress is: UBCFisheries Centre,Aquatic EcosystemsResearch Laboratory, 2202Main Mall, Vancouver, British Columbia,Canada, V6T 1Z4. Our fax number is (604)822-8934, and our email address isSeaNotes@fisheries.ubc.ca. All queries,subscription requests, and electronicaddress changes should be addressed toMegan Bailey, Sea Around Us NewsletterEditor.The Sea Around Us website may be foundat www.seaaroundus.org and contains up-to-date information on the project.The Sea Around Us project is a scientific collaborationbetween the University of British Columbia and the PewEnvironmental Group. The Group supports nonprofitactivities in the areas of culture, education, the environment,health and human services, public policy and religion. Basedin Philadelphia, the Group makes strategic investments to helporganizations and citizens develop practical solutions todifficult problems. In 2000, with approximately $4.8 billion inassets, the Group committed over $235 million to 302nonprofit organizations. ISSN 1713-5214   Sea Around Us (ONLINE)From 2000to 2005, anaverage of850,000tonnes offish,crustaceans,molluscsand otherinvertebrates,werecommerciallycaught inthe Gulf ofMexico.Figure 2. Spatial distribution of the average (2000-2005) annual landedvalue of reported commercial fisheries catches in the Gulf of Mexico.The area closed to commercial fishing (including both federal and statewithin the US EEZ as of July 22nd 2010) accounts for approximately 18%of the total value of landings within the LME.  The remainder of the USEEZ still open to fishing accounts for 56%, while Mexican watersaccount for 26% of total landed value.  Less than 0.1% of the annuallanded value is derived from the two High Seas areas and Cuban waters.Gulf fisheries - Continued from page 1Continued on page 3 - Gulf fisheriesSea Around Us Project provide a unique opportunityto explore potential effects of the spill oncommercial fisheries in this Large Marine Ecosystem(LME).  While these databases supply detailedinformation on a global scale, they may be easilyqueried to understand trends occurring in smallergeographic regions, such as the Gulf of Mexico.Using data detailing the location and quantity ofspecies reportedly caught by fishers throughout theGulf [4], in addition to information regarding theprice that they receive when they sell their catch[5], spatial maps illustrating recent trends in catchand landed value were generated for this study.From 2000 to 2005, an annual average ofapproximately 850,000 tonnes of fish, crustaceans,molluscs and other invertebrates, primarilyinhabiting the highly productive continental shelfarea, were commercially caught in the Gulf ofMexico.  The majority of this catch originatedwithin the 200 nautical mile limit of the UnitedStates’ Exclusive Economic Zone (EEZ), followed bylandings within Mexican waters.  The total landedvalue of this catch was estimated at approximately$1.38 billion US.As oil slicks visible on the sea surface grew in sizefollowing the spill (Figure 1), the U.S. NationalOceanographic and Atmospheric Administration(NOAA), as well as the States of Florida, Alabama,Mississippi and Louisiana, declared portions offederal and state waters closed to commercialfishing in an effort to promote seafood safety andensure consumer confidence.  The location of thisclosed area in relation to mapped average catch andlanded value was analyzed to provide cluesregarding potential economic losses to commercialfisheries in the region (Figure 2).As of July 22, 2010, over 10% of the total surfacearea of the Gulf and nearly 25% of the US Gulf EEZwas closed to commercial fishing operations. Figure2 demonstrates that this closure overlapped withhighly productive and economically valuable shelfhabitats accounting for 18% of the total annual valueof reported commercial landings within the Gulf ofMexico.  This represents a potential annual loss ofPage 3 Sea Around Us – September/October 2010It is evidentthat the oilspill hasclearlyimpacted anarea ofcrucialeconomicimportance.Gulf fisheries - Continued from page 2Continued on page 4 - Dispersant$247 million to be suffered by U.S. commercialfishers.  While the majority of US catch within theclosed area during 2000 to 2005 was composed ofGulf menhaden, landings of brown and whiteshrimp generated the greatest value (12% of theannual US total in the Gulf, combined) due to highconsumer demand and associated prices, followedby blue crabs (4%), Gulf menhaden (3%), andeastern oysters (1%).  Potential impacts on valuableinvertebrate fisheries may be compounded by thefact that relatively immobile, benthic organisms arelikely to suffer higher rates of mortality as a result ofthe toxic effects of oil compared to more mobilefish species [6].  In addition, the capacity of habitatsand species to recover from the effects of oil,methane, and dispersants may have already beencompromised due to pre-existing sources of stress,including nutrient-laden freshwater discharge fromthe Mississippi River resulting in periodic oxygen-depleted ‘dead zones’, and bottom habitatdestruction due to extensive shrimp trawling.While this study does not attempt to address the fullrange of biological and economic consequences ofthe Deepwater Horizon oil spill on fisheries in theGulf of Mexico, it does provide a preliminaryperspective on one aspect of the puzzle, given pre-oil spill trends. It is evident that the oil spill hasclearly impacted an area of crucial economicimportance within the Gulf of Mexico. Missing fromthe situation presented here are the values torecreational fishers, an important sector in theregion.During the months following the spill, my head hasbeen filled with nostalgic thoughts of flour-likesand squeaking beneath my feet while playing onthe beaches of Seaside, Florida, hours spentsearching the seashore in Captiva for the beautifulshells that still sit in a bowl in my living room, anddevouring a 10 lb bag of steamed clams boughtfrom a fishers by the side of the road in Cedar Key.How will future generations of vacationingfamilies, Gulf-coast residents and fishers rememberthis region?  Hopefully, expectations ofenvironmental resilience along with a continueddedication to clean-up operations will facilitate aswift recovery.References:1.http://www.restorethegulf.gov/release/2010/08/02/us-scientific-teams-refine-estimates-oil-flow-bps-well-prior-capping2. Crone TJ, Tolstoy M (2010) Magnitude of the2010 Gulf of Mexico Oil Leak. Science 330:634.3. http://www.ens-newswire.com/ens/aug2010/2010-08-02-091.html4. Watson R, Kitchingman A, Gelchu A, Pauly D(2004) Mapping global fisheries: sharpeningour focus. Fish and Fisheries 5: 168-177.5. Sumaila R, Marsden AD, Watson R, Pauly D (2007)A global ex-vessel fish price database:construction and applications. Journal ofBioeconomics 9: 39-51.6. Teal JM, Howarth RW (1984) Oil spill studies: areview of ecological effects.Environmental Management 8: 27-44.At the end of August, I moved to Vancouverfrom Sanibel Island, Florida. Sanibel is a tinyisland in the Gulf of Mexico, where millionsof litres of oil have spilled since the DeepwaterHorizon explosion on April 20, 2010. When peoplelearn that I am from the Gulf region, they usuallyask how much oil I saw on nearby beaches.Surprisingly, the answer is none.Oil has washed ashore in the northern region ofthe Gulf, closer to the spill, but southern Florida’scoast appears largely oil-free. The absence ofvisible oil in southwest Florida is probably due to acombination of natural and anthropogenic factors.The Loop Current flows relatively far offshore, so ithas not played a significant part in carrying oil ortarballs to SW Florida’s coastal areas (see figure).Also, major storms with the potential to push oilinland have bypassed the area so far this hurricaneseason.Despite the pristine beach conditions in SW Florida,it is important to remember that the lack of visibleoil does not necessarily indicate a lack of presence.Chemical dispersants played a key role in hidingsurface oil that might otherwise have washed upon beaches today.Dispersants are chemicals that break oil into smalldroplets, which are then distributed throughoutOil dispersants:The easy way to clean houseby Leah BieryPage 4Sea Around Us – September/October 2010Publications Mail Agreement No: 41104508Usingdispersantsto hide theoil was afast andeasy way tomaximizethe numberof cleanbeachesand keepthe generalpublichappy.the water column by waveaction and currents.Dispersants do not clean upor get rid of the oil – theysimply spread it out. In Julyalone, the US dropped onethird of the world’s supply ofdispersants into the Gulf ofMexico, effectively makingthe oil difficult to find.You can compare the use ofdispersants to a commonscenario that most everyoneexperienced as a child –hiding a mess from yourparents. Your mom is angryabout the messy state of your room, so she tellsyou to clean it up. Instead of cleaning up the rightway – putting each item where it belongs – youshove everything under the bed, hiding theproblem. By using dispersants, the responsibleparties were hiding the oil spill instead of cleaningit up.Hiding the mess is an attractive temporary solution,but the problem becomes apparent when yourmom looks under the bed. Now you are in bigtrouble. The consequences are much worse than ifyou had just initially taken the responsibility andtime to clean up correctly.A recent study of core samples taken frommultiple locations in the Gulf revealed as much as5 cm layers of oil on top of normal bottomsediments. Samantha Joye, a professor from theUniversity of Georgia who collected the coresamples, said in an interview with NPR, “The sheercoverage here is leading us all to come to theconclusion that it has to be sedimented oil fromthe oil spill, because it’s all over the place.” (http://www.npr.org/templates/story/story.php?storyId=129782098&ps=cprs)Using dispersants to hide the oil was a fast andeasy way to maximize the number of cleanbeaches and keep the general public happy bymaking the unpleasant effects of the oil spillappear to go away. However, the long-termenvironmental and ecological effects of spreadingoil throughout the water column are unknown. TheObama administration’s leader of the scientificresponse to the oil spill, Marcia McNutt, admittedlast week that the government decided to usedispersants without prior knowledge of thepotential environmental effects, saying “there wasno science when you apply [chemical dispersants]in the deep sea — we didn’t know the impacts onsea life.”She also acknowledged that it may be yearsbefore we know the full impact of the decision(http://www.poptech.org/blog/marcia_mcnutt_on_uncertainty_in_the_flow).There is a strongchance that the combination of oil and chemicalingredients in the dispersants will have harmfuleffects on marine life and potentially the humanswho choose to consume that seafood in the nearfuture.Naturally, oil floats on the surface. This makes itpossible (although difficult) to clean up. Sending oilto the bottom of the ocean makes it virtuallyimpossible to remove. It also damages sea grassbeds and coral reefs, and the oil is inadvertentlyconsumed by mussels and other filter feeders –many of which make up the base of the Gulf foodweb. The chemicals in the oil (mixed with themysterious chemicals in the dispersants) couldaccumulate up the food chain over time until highlevels are found in commonly-consumed species.The U.S. Food and Drug Administration is monitoringseafood from the Gulf of Mexico carefully, and anumber of independent studies are in progress.The long-term effects of dispersants in the Gulf ofMexico are unclear at this point. The Gulf is one ofthe world’s top food-producing regions, sodispersants could have huge implications forfisheries. Thanks to dispersants, people in southwestFlorida can enjoy the beaches now, but they maynot be able to enjoy local seafoodsafely in the years to come.Dispersant - Continued frompage 3Major currents in the Gulf of Mexico. Near SW Florida, the Loop Current flows far enoughoffshore that it has not carried oil to beaches.Page 5 Sea Around Us – September/October 2010The SeafoodPrint and the revival ofthe primary production requiredby Wilf Swartz and Daniel PaulyThe October issue of the NationalGeographic magazine featured a story titled‘Time for a Sea Change’ [1] withcontributions from the Sea Around Us Project.  Thefocus of the story was the ecological footprint ofour seafood consumption, or SeafoodPrint.  Muchlike the Ecological Footprints of Rees andWackernagel [2], the SeafoodPrint is an attempt toexpress the impact of seafood consumption interms of the productivity of the ecosystems fromwhich they are derived. For this purpose, werevived the concept of the Primary ProductionRequired (PPR) to sustain global fisheries, originallyproposed by Pauly and Christensen in 1995 [3].the current level of seafood consumption. Weused the PPR conversion (based on the meantrophic transfer efficiency of marine systems,estimated as 10% by Pauly and Christensen1995) to compute the ecological footprints (i.e.,SeafoodPrints) of fish-consuming countries.  Thehigher on the food web a fish is, the larger thefootprint resulting from consuming such fish(Figure 1).  Consuming 1 kg of northern bluefintuna, at a trophic level 4.43, would be equivalentto 2,700kg of SeafoodPrint. Compare that withthe SeafoodPrint for consuming 1 kg of Peruviananchovies, at a trophic level 2.7, calculated as theequivalent of 500kg.For the National Geographic piece, we computedthe SeafoodPrint for all seafood consumingcountries using the information on their fisherieslandings, imports and exports. It has been widelyrecognized that seafood is one of the most tradedfood commodities in international markets, withthe markets of the industrialized countriesincreasingly dependent on imports from foreignwaters to meet their domestic demands [4].Hence, rather than simply examining the fisheriesof each country, it was important that thePPR was designed to overcome the fact thatevery fish is different. Or moreanthropocentrically, every kind of seafood isdifferent. Since seafood covers a wide spectrumof species across marine food webs, theecological impacts of seafood consumption alsovary. While recognizing that assessments of thetrue ecological impacts of seafood consumptionwould require tremendous amounts ofinformation about the status of each stock, fishingpractices etc., we defined, for our purpose, theecological impacts (i.e., footprints) as the amountof marine primary productivity required to sustain Continued on page 6 - Seafood printFigure 1.  Schematics for computation of Seafood Print, estimated using 10% transfer efficiency between trophic levels, i.e.,SeafoodPrint = (consumption)*10(TL-1). It has beenwidelyrecognizedthat seafoodis one of themost tradedfoodcommoditiesininternationalmarkets...Page 6Sea Around Us – September/October 2010Seafood print - Continued from page 5Figure 2.  Primary production required to sustain globalfisheries landings expressed as percentage of local primaryproduction.Figure 3. Time series of areas exploited by marine fisheries (PPR>10% PP) bylatitude class, expressed as a percentage of the total ocean area.SeafoodPrints were applied toconsumption. The result was notsurprising with China as the largestconsumer of seafood, followed byJapan and the United States. Withbenchmarks now established, wehope that the concept ofSeafoodPrints will resonate withconsumers and encourage a shift indemand from high trophic species tospecies that are sustainable and havelower ecological footprints.Another outcome from the revival ofthe PPR is our new article inPLoS ONE [5] which applied the PPR ofglobal fisheries for assessing the rates of theirspatial expansion. For this study, we used threedifferent threshold levels of PPR as percentage oflocal primary production to define ‘fisheriesexploitation,’ and applied them to the Sea AroundUs catch database (Figure 2). This approach allowedus to assign an exploitation status to each square ofour ocean grid (exploited vs. unexploited) andtrace the changes in their status over the years(Figure 3). Our  analysis shows that fisheriesexpanded at the rate of about one million km2 peryear from 1950 to 1980, but this increased by 3-fold, following the series of EEZ declarations in the1980s, with a large proportion of new fishinggrounds coming from southern oceans.We also found that a third of the world’s oceansand two-thirds of continental shelves are currentlyexploited at a level where PPR of fisheries exceeds10%  of local primary production, leaving relativelyinaccessible waters in the Arctic and Antarctic asthe last remaining ‘frontiers.’All of this should come as no surprise.  The declineof newly exploited areas since the 1990s, whichcorresponds with the decline in the globallandings, implies that the era of great expansionhas come to an end. With limited room forexpansion, the path toward sustainability of globalfisheries must come through reduction of ourSeafoodPrint. So let us hope that the article inNational Geographic will raise a trickle then a floodof concerned citizen voices insisting that it isindeed “Time for a Sea Change”.References:1. Greenberg, P (2010 October). Time for a SeaChange. National Geographic, 78-89.2. Rees, B and Wackernagel, M (1996). Ourecological footprint: reducing humanimpact on the Earth. New SocietyPublishers, Gabriola Island, BC. 176p.3. Pauly, D and Christensen, V (1995). Primaryproduction required to sustain globalfisheries. Nature, 374: 255-257.4. Swartz, W, Sumaila, UR, Watson, R and Pauly, D(2010). Sourcing seafood for the threemajor markets: The EU, Japan and the USA.Marine Policy, 34, 1366-1373.5. Swartz, W, Sala, E, Tracey, S, Watson, R and Pauly,D (2010). The spatial expansion andecological footprint of fisheries (1950 topresent). PLoS ONE, 5(12):  e15143.doi:10.1371/journal.pone.0015143. ... a third ofthe world’soceans andtwo-thirdsofcontinentalshelves arecurrentlyexploited ata levelwhere PPRof fisheriesexceeds10% of localprimaryproduction


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