Testing source-sink theory: the spill-over of mussel recruits beyond marine protected areas

Ludford, Adam; Cole, Victoria J.; Porri, Francesca; McQuaid, Christopher D.; Nakin, M. D. V.; Erlandsson, Johan

doi:10.1007/s10980-012-9739-y

Cited by 17 publications

(9 citation statements)

References 52 publications

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“…Stock assessments from intertidal ridges in the Coffee Bay area between 2001 and 2003 confirmed that the mussel beds were denuded with very low intertidal densities (less than 1 %) (Calvo-Ugarteburu, unpubl.). Since the natural recovery of mussel beds is so slow and there is no documented evidence yet of spill-over effects of mussel recruits and larvae from nearby Marine Protected Areas (MPAs) to exploited areas in the studied region (Ludford et al 2012), rehabilitating mussel beds along the coast became even more important in order for this biological resource to recover and the fishery to be rebuilt.…”

Section: The Brown Mussel Perna Perna In Coffee Baymentioning

confidence: 99%

Rehabilitating mussel beds in Coffee Bay, South Africa: Towards fostering cooperative small-scale fisheries governance and enabling community upliftment

Calvo-Ugarteburu

Raemaekers

Halling

2016

Ambio

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Along the coast of South Africa, marine resources play a significant role in supporting livelihoods and contributing to food security in impoverished rural communities. Post-apartheid fisheries laws and policies have begun to address traditional fishing rights and development needs, and new management arrangements are being implemented. One such initiative has been the Mussel Rehabilitation Project in Coffee Bay, which piloted a resource rehabilitation technique at several overexploited fishing sites. Mussel stocks in these exploited areas had dropped to under 1 % mussel cover, and during the project period, stocks increased to[80 % cover, supporting a sustainable harvest well above national daily bag limits. This stock enhancement was achieved only after the project had started to address social challenges such as the lack of local management institutions and the need to enhance food security. The project embarked on training and institution-building; it formed a robust community mussel management committee; and developed a local resource management plan, facilitating increased community participation in the day-to-day management of the resource. The project also saw the initiation of various ancillary projects aimed at improving food security and stimulating the local economy and hence alleviating pressure on the marine resources. Here we review this 10-year project's outcomes, and present lessons for smallscale fisheries governance in South Africa and internationally. We show, through empirical experience, that balancing stock rebuilding needs in a context of widespread poverty and dependency on natural resources by a local fisher community can only be addressed through an integrated approach to development. Participation of resource users and a thorough understanding of the local context are imperative to negotiating appropriate smallscale fisheries governance approaches. We recommend that the implementation of South Africa's newly minted SmallScale Fisheries Policy should begin with bottom-up, demonstrative resource management measures such as mussel rehabilitation. This type of initiative can deliver short-term food security benefits and foster social learning towards sustainable and cooperative fisheries governance.

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Section: The Brown Mussel Perna Perna In Coffee Baymentioning

confidence: 99%

Rehabilitating mussel beds in Coffee Bay, South Africa: Towards fostering cooperative small-scale fisheries governance and enabling community upliftment

Calvo-Ugarteburu

Raemaekers

Halling

2016

Ambio

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“…The power of knowledge and understanding for an improved environment was also clearly recognized, and the awareness campaigns and education programs were ranked the third most important strategy and received a high proxy together with laws against trade, showing awareness at both local and global scales. Temporal and/or spatial closures were viewed as a very important strategy; spatial closures are very common, e.g., in forms of no-take zones, and these closures can have benefits such as spillover effects of larvae, although for some species there is no evidence of such spillover effects (Ludford et al 2012). Closures in the intertidal zone are, however, still very rare in the WIO region.…”

Section: Discussionmentioning

confidence: 99%

Intertidal Zone Management in the Western Indian Ocean: Assessing Current Status and Future Possibilities Using Expert Opinions

Nordlund

Torre‐Castro

Erlandsson³

et al. 2013

AMBIO

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This expert opinion study examined the current status of the intertidal zone in the Western Indian Ocean (WIO) and ranked and discussed future management approaches. Information was gathered from scientists, practitioners, and managers active in the WIO region through a questionnaire and a workshop. The experts stated that the productive intertidal environment is highly valuable for reasons such as recreation, erosion protection, and provision of edible invertebrates and fish. Several anthropogenic pressures were identified, including pollution, harbor activities, overexploitation, and climate change. The experts considered the WIO intertidal zone as generally understudied, undermanaged, and with poor or no monitoring. The most important management strategies according to the expert opinions are to develop and involve local people in integrated coastal zone management (ICZM), to increase knowledge on species-environment relationships, and to develop awareness campaigns and education programs. To improve coastal environmental management and conservation, we argue that the intertidal zone should be treated as one organizational management unit within the larger framework of ICZM.

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“…Protection from harvest within MPAs (i.e., notake reserves), especially in the case of sedentary species such as bivalves, can increase biomass, abundance, average size of individual species, as well as overall species diversity (Halpern, 2003;Lubchenco et al, 2003;Sobel and Dahlgren, 2004;Schulte et al, 2009;Christie et al, 2010;Ludford et al, 2012). In contrast, some studies indicate a decline or no apparent difference in these biological measures inside vs. outside of no-take reserves (Dufour et al, 1995;Valles et al, 2001;Tupper and Rudd, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…In cases where the abundance and size of individuals of a given species within reserves is greater and larger, respectively, than outside reserves, greater overall reproductive output can lead to a "spillover effect" of larvae and individuals from inside to outside the reserve (Sobel and Dahlgren, 2004;Christie et al, 2010). "Spill over" of larvae or individuals from reserves to exploited subpopulations is beneficial through supplementing exploited subpopulations via supplying recruits (Kellner et al, 2007;Ludford et al, 2012). Because marine reserves are generally not demographically closed (i.e., often connected via emigration/immigration with other subpopulations through larval dispersal), there is a high potential for exchange of larvae spawned within no-take reserves and harvested sites.…”

Section: Introductionmentioning

confidence: 99%

Oyster Demographics in Harvested Reefs vs. No-Take Reserves: Implications for Larval Spillover and Restoration Success

et al. 2017

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Fishery species that reside in no-take, marine reserves often show striking increases in size and abundance relative to harvested areas, with the potential for larval spillover to harvested populations. The benefits of spillover, however, may not be realized if the populations or habitats outside of reserves are too degraded. We quantified oyster population density and demographics such as recruitment, growth, mortality, and potential larval output as a function of two types of oyster management strategies in Pamlico Sound, North Carolina, USA: (1) natural reefs + harvested and (2) restored reefs + harvested. We compared these data to demographic data collected as a function of a third type of management strategy, (3) restored reefs + protected from harvest. Mean oyster recruitment was ∼12 times higher in restored + harvested reefs than in natural + harvested reefs. Mean total oyster density was ∼8-to 72-times higher in restored + protected reefs than in restored + harvested or natural + harvested reefs, respectively. Moreover, harvested reefs exhibited truncated size structure, and few or no individuals greater than legal size (75 mm), whereas protected reefs typically had a polymodal size structure, including many large individuals. We estimate that restored + protected reefs have ∼4 to 700 times greater potential larval output m −2 than restored + harvested or natural + harvested reefs, respectively. After accounting for total sound-wide areal coverage of each reef type, total potential larval output from restored + protected reefs was ∼6 times greater than that from natural + harvested and restored + harvested reefs. Marine reserves can potentially subsidize harvested populations via larval spillover, however, in the case of oyster reefs in Pamlico Sound, the relatively degraded conditions of natural reefs (e.g., low vertical relief, low shell volume per square meter) may not provide much in the way of suitable settlement substrate to realize the benefits of larval spillover from reserves. Restoration of oyster reefs, even with a thin veneer of substrate, may improve settlement substrate to increase the benefits of larval spillover from reserves.

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Testing source-sink theory: the spill-over of mussel recruits beyond marine protected areas

Cited by 17 publications

References 52 publications

Rehabilitating mussel beds in Coffee Bay, South Africa: Towards fostering cooperative small-scale fisheries governance and enabling community upliftment

Rehabilitating mussel beds in Coffee Bay, South Africa: Towards fostering cooperative small-scale fisheries governance and enabling community upliftment

Intertidal Zone Management in the Western Indian Ocean: Assessing Current Status and Future Possibilities Using Expert Opinions

Oyster Demographics in Harvested Reefs vs. No-Take Reserves: Implications for Larval Spillover and Restoration Success

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