Omar Defeo

Oyster Reefs at Risk and Recommendations for Conservation, Restoration, and Management

Native oyster reefs once dominated many estuaries, ecologically and economically. Centuries of resource extraction exacerbated by coastal degradation have pushed oyster reefs to the brink of functional extinction worldwide. We examined the condition of oyster reefs across 144 bays and 44 ecoregions; our comparisons of past with present abundances indicate that more than 90% of them have been lost in bays (70%) and ecoregions (63%). In many bays, more than 99% of oyster reefs have been lost and are functionally extinct. Overall, we estimate that 85% of oyster reefs have been lost globally. Most of the worlds remaining wild capture of native oysters (> 75%) comes from just five ecoregions in North America, yet the condition of reefs in these ecoregions is poor at best, except in the Gulf of Mexico. We identify many cost-effective solutions for conservation, restoration, and the management of fisheries and nonnative species that could reverse these oyster losses and restore reef ecosystem services.

Navigating transformations in governance of Chilean marine coastal resources

Marine ecosystems are in decline. New transformational changes in governance are urgently required to cope with overfishing, pollution, global changes, and other drivers of degradation. Here we explore social, political, and ecological aspects of a transformation in governance of Chiles coastal marine resources, from 1980 to today. Critical elements in the initial preparatory phase of the transformation were (i) recognition of the depletion of resource stocks, (ii) scientific knowledge on the ecology and resilience of targeted species and their role in ecosystem dynamics, and (iii) demonstration-scale experimental trials, building on smaller-scale scientific experiments, which identified new management pathways. The trials improved cooperation among scientists and fishers, integrating knowledge and establishing trust. Political turbulence and resource stock collapse provided a window of opportunity that triggered the transformation, supported by new enabling legislation. Essential elements to navigate this transformation were the ability to network knowledge from the local level to influence the decision-making processes at the national level, and a preexisting social network of fishers that provided political leverage through a national confederation of artisanal fishing collectives. The resultant governance scheme includes a revolutionary national system of marine tenure that allocates user rights and responsibilities to fisher collectives. Although fine tuning is necessary to build resilience of this new regime, this transformation has improved the sustainability of the interconnected social–ecological system. Our analysis of how this transformation unfolded provides insights into how the Chilean system could be further developed and identifies generalized pathways for improved governance of marine resources around the world.

Latin American benthic shellfisheries: emphasis on co-management and experimental practices

In Latin America the small-scale fishery ofmarine benthic invertebrates is based onhigh-value species. It represents a source offood and employment and generates importantincomes to fishers and, in some cases, exportearnings for the countries. In the review, wedefine 2 key concepts: small-scale fishery andco-management. We address the temporalextractive phases which Latin Americanshellfish resources have experienced, and thecorresponding socio-economic and managerialscenarios. We include 3 study cases in whichco-management and field experimentation havebeen used on different temporal and spatialscales: (a) the muricid gastropod (Concholepas concholepas) in Chile; (b) theyellow clam (Mesodesma mactroides) inUruguay; and (c) the spiny lobster (Panulirusargus) in Mexico. We demonstratethat co-management constitutes an effectiveinstitutional arrangement by which fishers,scientists and managers interact to improve thequality of the regulatory process and may serveto sustain Latin American shellfisheries overtime. The main factors supporting co-managementare: (a) a comparatively reduced scale offishing operations and well-defined boundariesfor the management unit; (b) the allocation ofinstitutionalized co-ownership authority tofishers; (c) the voluntary participation of thefishers in enforcing regulations; (d) theimprovement of scientific information(including data from fishers) to consolidatethe management schemes; (e) the incorporation ofcommunity traditions and idiosyncrasies; and (f)the allocation of territorial use rights forfisheries under a collaborative/voluntarycommunity framework. Chile is identified as anexample in which basic ecological and fisheryconcepts have been institutionalized throughmanagement practices and incorporated into theLaw. Several factors have precludedshellfishery management success in most of theLatin American countries: (a) the social andpolitical instability, (b) the underestimationof the role of fisheries science in managementadvice, (c) the inadequacy of data collectionand information systems, (d) the poorimplementation and enforcement of managementpractices and (e) the uncertainty in short-termeconomic issues.In the review, we also show that in LatinAmerica, large-scale fishery experiments arestarting to play an important role in theevaluation of alternative management policieson benthic shellfisheries, especially whenaccompanied by co-management approaches thatexplicitly involve the participation offishers. Fisher exclusion experiments havedemonstrated changes in unexploited versusexploited benthic shellfish populations and inthe structure and functioning of communities.The information has been used by scientists toapproach system elasticity. Ecological andfishery related knowledge has been translatedinto novel co-managerial strategies. Thesedentary nature of the shellfish speciesanalyzed in this review allowed localizedexperiments with different levels of stockabundance and fishing intensity (e.g., marinereserves or maritime concessions versus openaccess areas). This includes the establishmentof closed seasons as de facto managementexperiments, which proved useful in evaluatingthe capacity of passive restocking of depletedareas and for the quantification of populationdemographic features. The precise location offishing grounds provided reliable area-specificestimates of population density and structure,catch, and fishing effort. This allowed theallocation of catch quotas in each fishingground. We also discuss the reliability andapplicability of spatially explicit managementtools. Marine Protected Areas (MPAs) andTerritorial User Rights in Fisheries (TURFs)fulfilled objectives for management andconservation and served as experimentationtools. The examples provided in our reviewinclude a comparative synthesis of the relativeusefulness of alternative spatially explicitmanagement tools under a framework ofmanagement redundancy. The cross-linkagebetween fishery experimental managementprotocols and the active participation offishers is suggested as the strategy to befollowed to improve the sustainable managementof small-scale shellfisheries in Latin America.Finally, we discuss the future needs,challenges and issues that need to be addressedto improve the management status of thesmall-scale shellfisheries in Latin America,and, in general, around the world. We concludethat for the sustainability of shellfishresources there is an urgent need to look forlinkages between sociology, biology andeconomics under an integrated managementframework. Fishers, and not the shellfish, mustbe in the center of such a framework.

Healing small-scale fisheries by facilitating complex socio-ecological systems

The current global fisheries crises have immense implications for the health and viability of animal populations, as well as the ecosystems and habitats that support this biodiversity. These crises have provoked a wide variety of management solutions and alternatives that are closely aligned with other small-scale resource extraction conservation approaches, but have been analyzed separately from the common-pool resource management literature. We summarize findings from an analysis of progressive small-scale fisheries worldwide and find that solutions arise from a historical trial and error management process as problems become dire. We find high success in the social organization and regulation of resources among these progressive fisheries but poor evidence for improved ecosystems. Based on evidence provided by the most progressive fisheries, we suggest a change in policy towards the management of small-scale fisheries. This change includes four major avenues of problem solving that focus on facilitating socio-ecological processes rather than primarily promoting a high level of quantitative science and implementing findings, technological concepts, or tools. Adoption is often culturally and context specific and, therefore, the above often have poor success when not socially integrated. We encourage facilitating and catalyzing local-level adoption of rules that create limits to appropriation and technology, since it is increasingly recognized that such limits are key solutions to the threats. This will be achieved if policy and actions (1) encourage professionalism (formation of “societies”, setting standards, certification, self-policing, appropriate technology, etc.), (2) create forums where all opinions about solutions, the status of targeted species, and environmental requirements are represented, (3) promote social rules that consider the realities and limits of the households and local social economy, and (4) craft solutions tailored to the specific and agreed upon diagnoses. We predict that as this socio-ecological process matures, it will also increase the inclusiveness of resource management goals to include non-use factors, such as biodiversity and other ecosystem services, which are still poorly evaluated and managed in even the most progressive small-scale fisheries.

More than One Bag for the World Fishery Crisis and Keys for Co-management Successes in Selected Artisanal Latin American Shellfisheries

Global concerns about the depletion of marine stocks have been widely documented in industrial fisheries. However, small-scale artisanal fisheries constitute a second component for the world fishery crisis, normally ignored or erroneously lumped into the industrial component. In this paper we first present a brief comparison between industrial and artisanal fisheries, highlighting the differences between them and the differential feasibility for implementing management options. We propose that industrial and artisanal fishery problems have to be treated separately and thus cannot be lumped into a single “fishing bag”. Among artisanal fisheries, we focus on coastal benthic shellfisheries, highlighting that their sedentary or sessile nature make them amenable to implement spatially-explicit management tools such as rotation of areas and territorial user rights (TURFs). Then, using long-term catch trends and selected examples, we demonstrate the power and validity of co-management for some Latin American shellfisheries, notably in Chile and Mexico, and stress the need to institutionalize the existent fishery knowledge. Several idiosyncratic properties of co-management in our Latin American examples have been useful to sustain the resources over time, including: (a) allocations of TURFs, (b) Community Fishery Quotas, which may be sub-allocated to families, (c) community-based and family-oriented sociological and organizational context of co-management, which may drive short and long-term market forces.

Adaptations of bivalves to different beach types

Burrowing ability, shape and density of 12 bivalve species from a wide range of beach types were compared as part of a general investigation of the adaptations of bivalves to the swash climates experienced on exposed sandy beaches. The genera used were Donax, Mesodesma, Tivela, Siliqua, Atactodea, Paphies and Donacilla. Burrowing rates varied widely and burrowing ability showed no relation to beach type along the reflective/dissipative beach gradient, i.e. from beaches with low wave energy and coarse sand to beaches with high wave energy and fine sand. Burrowing rate indices (BRIs) ranged from 2 to 17 (rapid to very rapid) and tended to be higher for juveniles of most species. Bivalve species from dissipative beaches varied in shape from almost blade-shaped to almost spherical, whereas those from reflective beaches were more uniform generally wedge-shaped. Species with the most flattened shapes and (greatest height/width ratios) tended to burrow fastest. Striking interspecific differences were found in densities of whole intact bivalves, these ranging from 1.04 g · cm−3 to 2.10 g · cm−3. The highest densities were recorded in bivalves from reflective beaches and the lowest in bivalves from dissipative beaches. Bivalve species typical of intermediate and reflective beaches were successfully separated from those typical of dissipative beaches on the basis of their density, morphology and BRI, particularly their size and density, using discriminant analysis. It is concluded that small species with high density and streamlined shape are best adapted to the dynamic swash conditions that characterise reflective beaches.

Eco-Label Conveys Reliable Information on Fish Stock Health to Seafood Consumers

Concerns over fishing impacts on marine populations and ecosystems have intensified the need to improve ocean management. One increasingly popular market-based instrument for ecological stewardship is the use of certification and eco-labeling programs to highlight sustainable fisheries with low environmental impacts. The Marine Stewardship Council (MSC) is the most prominent of these programs. Despite widespread discussions about the rigor of the MSC standards, no comprehensive analysis of the performance of MSC-certified fish stocks has yet been conducted. We compared status and abundance trends of 45 certified stocks with those of 179 uncertified stocks, finding that 74% of certified fisheries were above biomass levels that would produce maximum sustainable yield, compared with only 44% of uncertified fisheries. On average, the biomass of certified stocks increased by 46% over the past 10 years, whereas uncertified fisheries increased by just 9%. As part of the MSC process, fisheries initially go through a confidential pre-assessment process. When certified fisheries are compared with those that decline to pursue full certification after pre-assessment, certified stocks had much lower mean exploitation rates (67% of the rate producing maximum sustainable yield vs. 92% for those declining to pursue certification), allowing for more sustainable harvesting and in many cases biomass rebuilding. From a consumer’s point of view this means that MSC-certified seafood is 3–5 times less likely to be subject to harmful fishing than uncertified seafood. Thus, MSC-certification accurately identifies healthy fish stocks and conveys reliable information on stock status to seafood consumers.

Give Beach Ecosystems Their Day in the Sun

The Intergovernmental Panel on Climate Change Fourth Assessment Report ([ 1 ][1]) largely overlooked the impacts of climate change on marine ecosystems ([ 2 ][2]). In their Review (“The impact of climate change on the worlds marine ecosystems,” 18 June, p. [1523][3]), O. Hoegh-Guldberg and J. F

Variation of a sandy beach macrobenthic community along a human-induced environmental gradient

Abstract Among the diverse sources of impact on sandy coasts, man-made freshwater flows and discharges of sewage effluents strongly modify environmental quality by changing salinity and nutrient regimes. However, sandy beaches, which occupy three-quarters of the worlds shoreline, have received relatively little attention concerning consequences of this human-induced disturbance on the structure and dynamics of resident fauna. This paper reports the spatial effects of a freshwater canal discharge (Canal Andreoni) on the habitat and resident macrobenthos of an exposed sandy beach through a combined analysis of communities, populations and the surrounding habitat in three sites defined by previous studies as undisturbed (Barra), moderately disturbed (Coronilla) and grossly disturbed (Andreoni). Andreoni showed significant lower values of salinity, beach width, swash width and slope. Abundance, biomass, species richness, diversity and evenness significantly decreased towards the source of disturbance and were significantly and positively correlated with spatial variations in salinity. Multiple regressions explained up to 36% of the variability, often resulting in models composed by only one significant predictor, salinity, which can be considered as an aggregate variable that carries itself with different simultaneous effects in the nearshore-surf zone environment. The cirolanid isopod Excirolana armata generally dominated all sites in abundance, but at significantly lower values in the grossly disturbed site. The suspension feeders Donax hanleyanus and Emerita brasiliensis, which were well represented at Barra and Coronilla, did not occur in Andreoni, where insects were the most commonly represented after E. armata. In addition, the number of species and abundance of polychaetes tended to decrease towards the canal mouth, with the exception of punctual pulses of abundance of Scolelepis gaucha at Coronilla. In terms of biomass, the isopod E. armata dominated at Andreoni and Coronilla, whereas the suspension feeders D. hanleyanus and E. brasiliensis dominated at Barra. It is concluded that artificial freshwater discharges could significantly influence the distribution, abundance and community attributes of the biota of sandy beaches, and that further study of these ecosystems should include human activities as important factors affecting spatial and temporal trends. The combination of natural experiments together with macrocosm field and microcosm laboratory experiments is also suggested as a rich research vein for detecting the extent of disturbances in sandy beaches.

Spatial structure of fish assemblages in a tropical estuarine lagoon: combining multivariate and geostatistical techniques

The spatial structure and seasonal changes of estuarine fish assemblages in the Cienaga Grande de Santa Marta (CGSM) were analysed based on four seasonal comprehensive surveys conducted in 1993-1994 and 1997. Geostatistical and multivariate techniques were used to: (a) determine seasonal changes in spatial distribution of the species richness, and (b) identify assemblages of estuarine fish and their relation to abiotic factors. Potential biotic interactions affecting the assemblage structure were also explored. A total of 11075 individuals representing 39 species were collected, with Eugerres plumieri, Diapterus rhombeus, Micropogonias furnieri, Mugil incilis, Cathorops spixii, Elops saurus and Anchovia clupeoides as dominant species between seasons. Spatial distribution of fish richness differed between rainy and dry seasons in each year, whereas species mapping showed spatial patchiness in 1993-1994 and gradients during 1997. Strong evidence of species saturation was found in all seasons, suggesting biotic interactions limiting species richness at a threshold density of ca. 50 ind./5000 m 2 . Marine, marine-estuarine and freshwater species were classified in each season according to their capability to cope with salinity fluctuations. Associations defined by functional feeding guilds were also identified. Empirical and statistic evidence showed that fish assemblages differed between seasons within each year, and each assemblage was always dominated by a small number of species, notably E. plumieri in both years 1993-1994 and 1997. Between-season differences in fish assemblage structure in the CGSM seem