1
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Chen R, Chaparro-Pedraza PC, Xiao S, Jia P, Liu QX, de Roos AM. Marine reserves promote cycles in fish populations on ecological and evolutionary time scales. Proc Natl Acad Sci U S A 2023; 120:e2307529120. [PMID: 37956293 PMCID: PMC10666098 DOI: 10.1073/pnas.2307529120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/10/2023] [Indexed: 11/15/2023] Open
Abstract
Marine reserves are considered essential for sustainable fisheries, although their effectiveness compared to traditional fisheries management is debated. The effect of marine reserves is mostly studied on short ecological time scales, whereas fisheries-induced evolution is a well-established consequence of harvesting. Using a size-structured population model for an exploited fish population of which individuals spend their early life stages in a nursery habitat, we show that marine reserves will shift the mode of population regulation from low size-selective survival late in life to low, early-life survival due to strong resource competition. This shift promotes the occurrence of rapid ecological cycles driven by density-dependent recruitment as well as much slower evolutionary cycles driven by selection for the optimal body to leave the nursery grounds, especially with larger marine reserves. The evolutionary changes increase harvesting yields in terms of total biomass but cause disproportionately large decreases in yields of larger, adult fish. Our findings highlight the importance of carefully considering the size of marine reserves and the individual life history of fish when managing eco-evolutionary marine systems to ensure both population persistence as well as stable fisheries yields.
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Affiliation(s)
- Renfei Chen
- School of Life Science, Shanxi Normal University, Taiyuan030000, China
| | | | - Suping Xiao
- School of Mathematics and Computer Science, Shanxi Normal University, Taiyuan030000, China
| | - Pu Jia
- Institute of Ecological Science, School of Life Sciences, South China Normal University, Guangzhou510631, China
| | - Quan-Xing Liu
- School of Mathematical Sciences, Shanghai Jiao Tong University, Shanghai200240, China
| | - André M. de Roos
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, AmsterdamNL-1098 XH, The Netherlands
- The Santa Fe Institute, Santa Fe, NM87501
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2
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Bosch NE, Monk J, Goetze J, Wilson S, Babcock RC, Barrett N, Clough J, Currey‐Randall LM, Fairclough DV, Fisher R, Gibbons BA, Harasti D, Harvey ES, Heupel MR, Hicks JL, Holmes TH, Huveneers C, Ierodiaconou D, Jordan A, Knott NA, Malcolm HA, McLean D, Meekan M, Newman SJ, Radford B, Rees MJ, Saunders BJ, Speed CW, Travers MJ, Wakefield CB, Wernberg T, Langlois TJ. Effects of human footprint and biophysical factors on the body-size structure of fished marine species. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2022; 36:e13807. [PMID: 34312893 PMCID: PMC9292308 DOI: 10.1111/cobi.13807] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/29/2021] [Accepted: 06/01/2021] [Indexed: 06/13/2023]
Abstract
Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.
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Affiliation(s)
- Nestor E. Bosch
- The School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
| | - Jacquomo Monk
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jordan Goetze
- Marine Science Program, Biodiversity and Conservation Science, Department of BiodiversityConservation and AttractionsKensingtonWestern AustraliaAustralia
- School of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Shaun Wilson
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Marine Science Program, Biodiversity and Conservation Science, Department of BiodiversityConservation and AttractionsKensingtonWestern AustraliaAustralia
| | | | - Neville Barrett
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
| | - Jock Clough
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
| | | | - David V. Fairclough
- Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional DevelopmentGovernment of Western AustraliaNorth BeachWestern AustraliaAustralia
| | - Rebecca Fisher
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Australian Institute of Marine ScienceIndian Ocean Marine Research CentreCrawleyWestern AustraliaAustralia
| | - Brooke A. Gibbons
- The School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
| | - David Harasti
- NSW Department of Primary Industries, Fisheries ResearchPort Stephens Fisheries InstituteTaylors BeachNew South WalesAustralia
| | - Euan S. Harvey
- School of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Michelle R. Heupel
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- Integrated Marine Observing System (IMOS)University of TasmaniaHobartTasmaniaAustralia
| | - Jamie L. Hicks
- Department for Environment and WaterMarine ScienceAdelaideSouth AustraliaAustralia
| | - Thomas H. Holmes
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Marine Science Program, Biodiversity and Conservation Science, Department of BiodiversityConservation and AttractionsKensingtonWestern AustraliaAustralia
| | - Charlie Huveneers
- College of Science and EngineeringFlinders UniversityBedford ParkSouth AustraliaAustralia
| | - Daniel Ierodiaconou
- School of Life and Environmental Sciences, Centre for Integrative EcologyDeakin UniversityWarrnamboolVictoriaAustralia
| | - Alan Jordan
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
- NSW Department of Primary Industries, Fisheries ResearchPort Stephens Fisheries InstituteTaylors BeachNew South WalesAustralia
| | - Nathan A. Knott
- Fisheries ResearchNSW Department of Primary IndustriesCoffs HarbourNew South WalesAustralia
| | - Hamish A. Malcolm
- Fisheries ResearchNSW Department of Primary IndustriesCoffs HarbourNew South WalesAustralia
| | - Dianne McLean
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Australian Institute of Marine ScienceIndian Ocean Marine Research CentreCrawleyWestern AustraliaAustralia
| | - Mark Meekan
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Australian Institute of Marine ScienceIndian Ocean Marine Research CentreCrawleyWestern AustraliaAustralia
| | - Stephen J. Newman
- Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional DevelopmentGovernment of Western AustraliaNorth BeachWestern AustraliaAustralia
| | - Ben Radford
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Australian Institute of Marine ScienceIndian Ocean Marine Research CentreCrawleyWestern AustraliaAustralia
- School of Agriculture and EnvironmentThe University of Western AustraliaPerthWestern AustraliaAustralia
| | - Matthew J. Rees
- Fisheries ResearchNSW Department of Primary IndustriesCoffs HarbourNew South WalesAustralia
| | - Benjamin J. Saunders
- School of Molecular and Life SciencesCurtin UniversityPerthWestern AustraliaAustralia
| | - Conrad W. Speed
- Australian Institute of Marine ScienceIndian Ocean Marine Research CentreCrawleyWestern AustraliaAustralia
| | - Michael J. Travers
- Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional DevelopmentGovernment of Western AustraliaNorth BeachWestern AustraliaAustralia
| | - Corey B. Wakefield
- Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional DevelopmentGovernment of Western AustraliaNorth BeachWestern AustraliaAustralia
| | - Thomas Wernberg
- The School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
- Institute of Marine ResearchHisNorway
| | - Tim J. Langlois
- The School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
- The UWA Oceans InstituteThe University of Western AustraliaPerthWestern AustraliaAustralia
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3
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Hopf JK, Caselle JE, White JW. Recruitment variability and sampling design interact to influence the detectability of protected area effects. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2022; 32:e2511. [PMID: 34870882 DOI: 10.1002/eap.2511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/18/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Correctly identifying the effects of a human impact on a system is a persistent challenge in ecology, driven partly by the variable nature of natural systems. This is particularly true in many marine fishery species, which frequently experience large temporal fluctuations in recruitment that produce interannual variations in populations. This variability complicates efforts to maintain stocks at management targets or detect the effects of rebuilding efforts. We address this challenge in the context of no-take marine reserves by exploring how variable larval recruitment could interact with the timing of reserve establishment and choice of sampling design to affect population dynamics and the detectability of reserve effects. To predict population changes in the years following a no-take reserve implementation, we first tested for periodicity in larval recruitment in an important U.S. Pacific coast recreational fishery species (kelp bass, Paralabrax clathratus) and then included that pattern in a population model. We also used this model to determine the detectability of population increases under alternative sampling approaches and minimum age sampled. Kelp bass larval recruitment in the Channel Islands, California, peaked every about six (major) and about two (minor) years. Our model showed that establishing a reserve during a peak or trough enhanced or delayed, respectively, the post-reserve population increases. However, establishing a reserve during a recruitment peak could obscure a failing reserve, that is, a reserve that is unable to secure longer-term metapopulation persistence. Recruitment peaks and troughs also interacted with sampling design to affect the detectability of reserve effects. Designs that compared inside-outside were the most robust to variable recruitment, but failed to capture whether the reserve has improved metapopulation growth. Designs that included a time element (e.g., before-after) are more suited to assessing reserve effectiveness, but were sensitive to recruitment variation and detectability can change year-to-year. Notably, detectability did not always increase monotonically with reserve age; the optimal time for detectability depended on the minimum age of organisms sampled and was greatest when the cohort of a major recruitment peak first appeared in the sampling. We encourage managers to account for variable recruitment when planning monitoring and assessment programs.
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Affiliation(s)
- Jess K Hopf
- Coastal Oregon Marine Experiment Station, Oregon State University, Newport, Oregon, USA
| | - Jennifer E Caselle
- Marine Science Institute, University of California, Santa Barbara, California, USA
| | - J Wilson White
- Coastal Oregon Marine Experiment Station, Oregon State University, Newport, Oregon, USA
- Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Newport, Oregon, USA
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4
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Lavin CP, Jones GP, Williamson DH, Harrison HB. Minimum size limits and the reproductive value of numerous, young, mature female fish. Proc Biol Sci 2021; 288:20202714. [PMID: 33715428 DOI: 10.1098/rspb.2020.2714] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Fisheries management relies on various catch and effort controls to preserve spawning stock biomass and maximize sustainable yields while limiting fishery impacts on marine ecosystems. These include species-specific minimum or maximum size limits to protect either small non-reproductive subadults, a portion of reproductively mature adults, or large highly fecund individuals. Protecting size classes of mature fish is expected to yield a viable source of larvae for replenishing populations and reduce the risk of recruitment overfishing, yet size-specific recruitment contributions have rarely been assessed empirically. Here, we apply genetic parentage analysis to measure the reproductive success of a size-structured population of a commercially important species of coral grouper (Plectropomus maculatus-Serranidae) in no-take marine reserves (NTMRs) in the Great Barrier Reef Marine Park, Australia. Although the per capita reproductive success of individual fish increases rapidly with body length, the numerous young mature female fish, below the minimum size limit (MSL) (38 cm total length), were responsible for generating disproportionately large contributions (36%) towards larval replenishment of both fished and reserve reefs. Our findings indicate that MSLs are an effective harvest control measure to safeguard a portion of the spawning stock biomass for coral grouper and supplement recruitment subsidies assured from NTMRs.
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Affiliation(s)
- Charles P Lavin
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Geoffrey P Jones
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia.,ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia
| | - David H Williamson
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Hugo B Harrison
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia.,Australian Institute of Marine Science, Townsville, Queensland, Australia
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5
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Brown CJ, Mellin C, Edgar GJ, Campbell MD, Stuart-Smith RD. Direct and indirect effects of heatwaves on a coral reef fishery. GLOBAL CHANGE BIOLOGY 2021; 27:1214-1225. [PMID: 33340216 DOI: 10.1111/gcb.15472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 11/04/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
Marine heatwaves are increasing in frequency and intensity, and indirectly impacting coral reef fisheries through bleaching-induced degradation of live coral habitats. Marine heatwaves also affect fish metabolism and catchability, but such direct effects of elevated temperatures on reef fisheries are largely unknown. We investigated direct and indirect effects of the devastating 2016 marine heatwave on the largest reef fishery operating along the Great Barrier Reef (GBR). We used a combination of fishery-independent underwater census data on coral trout biomass (Plectropomus and Variola spp.) and catch-per-unit-effort (CPUE) data from the commercial fishery to evaluate changes in the fishery resulting from the 2016 heatwave. The heatwave caused widespread, yet locally patchy, declines in coral cover, but we observed little effect of local coral loss on coral trout biomass. Instead, a pattern of decreasing biomass at northern sites and stable or increasing biomass at southern sites suggested a direct response of populations to the heatwave. Analysis of the fishery-independent data and CPUE found that in-water coral trout biomass estimates were positively related to CPUE, and that coral trout catch rates increased with warmer temperatures. Temperature effects on catch rates were consistent with the thermal affinities of the multiple species contributing to this fishery. Scaling-up the effect of temperature on coral trout catch rates across the region suggests that GBR-wide catches were 18% higher for a given level of effort during the heatwave year relative to catch rates under the mean temperatures in the preceding 6 years. These results highlight a potentially large effect of heatwaves on catch rates of reef fishes, independent of changes in reef habitats, that can add substantial uncertainty to estimates of stock trends inferred from fishery-dependent (CPUE) data. Overestimation of CPUE could initiate declines in reef fisheries that are currently fully exploited, and threaten sustainable management of reef stocks.
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Affiliation(s)
- Christopher J Brown
- Australian Rivers Institute - Coasts and Estuaries, School of Environment and Science, Griffith University, Nathan, Qld, Australia
| | - Camille Mellin
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
- The Environment Institute and School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Graham J Edgar
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
| | - Max D Campbell
- Australian Rivers Institute - Coasts and Estuaries, School of Environment and Science, Griffith University, Nathan, Qld, Australia
| | - Rick D Stuart-Smith
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
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6
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Chen R. Transient inconsistency between population density and fisheries yields without bycatch species extinction. Ecol Evol 2020; 10:12372-12384. [PMID: 33209295 PMCID: PMC7663084 DOI: 10.1002/ece3.6868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/06/2022] Open
Abstract
Recent studies have demonstrated the great advantages of marine reserves in solving bycatch problems by maintaining the persistence (i.e., avoid extinction) of endangered species without sacrificing the fisheries yields of target species. However, transient phenomena rather than equilibrium states of population dynamics still require further research. Here, with a simple and general model, the transient dynamics of the target fish species are investigated under management which minimizes extinction risk of the bycatch species. An interesting finding is that fisheries yields can strongly fluctuate even if population density both inside and outside marine reserve only slightly varies (or vice versa), leading to transient inconsistency between the population densities and fisheries yields. This finding suggests that population density dynamics of the target fish species cannot be used to predict the transient phenomena of fisheries yields (or vice versa) in fisheries management. However, the unpredictability can be receded as the sensitivity analyses show that a large marine reserve size and low escapement rate can shorten the transient duration.
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Affiliation(s)
- Renfei Chen
- School of Life ScienceShanxi Normal UniversityLinfenChina
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7
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Easter EE, Adreani MS, Hamilton SL, Steele MA, Pang S, White JW. Influence of protogynous sex change on recovery of fish populations within marine protected areas. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02070. [PMID: 31903628 DOI: 10.1002/eap.2070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Marine protected areas (MPAs) are increasingly implemented as a conservation tool worldwide. In many cases, they are managed adaptively: the abundance of target species is monitored, and observations are compared to some model-based expectation for the trajectory of population recovery to ensure that the MPA is achieving its goals. Most previous analyses of the transient (short-term) response of populations to the cessation of fishing inside MPAs have dealt only with gonochore (fixed-sex) species. However, many important fishery species are protogynous hermaphrodites (female-to-male sex-changing). Because size-selective harvest will predominantly target males in these species, harvesting not only reduces abundance but also skews the sex ratio toward females. Thus the response to MPA implementation will involve changes in both survival and sex ratio, and ultimately reproductive output. We used an age-structured model of a generic sex-changing fish population to compare transient population dynamics after MPA implementation to those of an otherwise similar gonochore population and examine how different features of sex-changing life history affect those dynamics. We examined both demographically open (most larval recruitment comes from outside the MPA) and demographically closed (most larval recruitment is locally produced) dynamics. Under both scenarios, population recovery of protogynous species takes longer when fishing was more intense pre-MPA (as in gonochores), but also depends heavily on the mating function, the degree to which the sex ratio affects reproduction. If few males are needed and reproduction is not affected by a highly female-biased sex ratio, then population recovery is much faster; if males are a limiting resource, then increases in abundance after MPA implementation are much slower than for gonochores. Unfortunately, the mating function is largely unknown for fishes. In general, we expect that most protogynous species with haremic mating systems will be in the first category (few males needed), though there is at least one example of a fish species (though not a sex-changing species) for which males are limiting. Thus a better understanding of the importance of male fish to population dynamics is needed for the adaptive management of MPAs.
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Affiliation(s)
- E E Easter
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, 28403, USA
| | - M S Adreani
- Department of Biology, California State University, Northridge, California, 91330, USA
| | - S L Hamilton
- Moss Landing Marine Laboratories, Moss Landing, California, 95309, USA
| | - M A Steele
- Department of Biology, California State University, Northridge, California, 91330, USA
| | - S Pang
- Moss Landing Marine Laboratories, Moss Landing, California, 95309, USA
| | - J W White
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, 28403, USA
- Department of Fisheries and Wildlife, Coastal Oregon Marine Experiment Station, Oregon State University, Newport, Oregon, 97365, USA
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8
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Hopf JK, Jones GP, Williamson DH, Connolly SR. Marine reserves stabilize fish populations and fisheries yields in disturbed coral reef systems. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01905. [PMID: 30985954 DOI: 10.1002/eap.1905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 02/20/2019] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
Marine reserve networks are increasingly implemented to conserve biodiversity and enhance the persistence and resilience of exploited species and ecosystems. However, the efficacy of marine reserve networks in frequently disturbed systems, such as coral reefs, has rarely been evaluated. Here we analyze a well-mixed larval pool model and a spatially explicit model based on a well-documented coral trout (Plectropomus spp.) metapopulation in the Great Barrier Reef Marine Park, Australia, to determine the effects of marine reserve coverage and placement (in relation to larval connectivity and disturbance heterogeneity) on the temporal stability of fisheries yields and population biomass in environmentally disturbed systems. We show that marine reserves can contribute to stabilizing fishery yield while increasing metapopulation persistence, irrespective of whether reserves enhance or diminish average fishery yields. However, reserve placement and the level of larval connectivity among subpopulations were important factors affecting the stability and sustainability of fisheries and fish metapopulations. Protecting a mix of disturbed and non-disturbed reefs, rather than focusing on the least-disturbed habitats, was the most consistently beneficial approach across a range of dispersal and reserve coverage scenarios. Placing reserves only in non-disturbed areas was the most beneficial for biomass enhancement, but had variable results for fisheries and could potentially destabilize yields in systems with well-mixed larval or those that are moderately fished. We also found that focusing protection on highly disturbed areas could actually increase variability in yields and biomass, especially when degraded reef reserves were distant and poorly connected to the meta-population. Our findings have implications for the design and implementation of reserve networks in the presence of stochastic, patchy environmental disturbances.
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Affiliation(s)
- Jess K Hopf
- College of Science and Engineering, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - Geoffrey P Jones
- College of Science and Engineering, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - David H Williamson
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
| | - Sean R Connolly
- College of Science and Engineering, ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, 4811, Australia
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9
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Abstract
Sustainable fisheries must ultimately reduce poverty while maintaining ecosystem productivity. On coral reefs, managing for 'concave' trophic pyramids might be a win-win for people and ecosystems, by providing higher-value fisheries and maintaining important ecological functions.
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10
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Abstract
Marine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass. Coral reefs provide ecosystem goods and services for millions of people in the tropics, but reef conditions are declining worldwide. Effective solutions to the crisis facing coral reefs depend in part on understanding the context under which different types of conservation benefits can be maximized. Our global analysis of nearly 1,800 tropical reefs reveals how the intensity of human impacts in the surrounding seascape, measured as a function of human population size and accessibility to reefs (“gravity”), diminishes the effectiveness of marine reserves at sustaining reef fish biomass and the presence of top predators, even where compliance with reserve rules is high. Critically, fish biomass in high-compliance marine reserves located where human impacts were intensive tended to be less than a quarter that of reserves where human impacts were low. Similarly, the probability of encountering top predators on reefs with high human impacts was close to zero, even in high-compliance marine reserves. However, we find that the relative difference between openly fished sites and reserves (what we refer to as conservation gains) are highest for fish biomass (excluding predators) where human impacts are moderate and for top predators where human impacts are low. Our results illustrate critical ecological trade-offs in meeting key conservation objectives: reserves placed where there are moderate-to-high human impacts can provide substantial conservation gains for fish biomass, yet they are unlikely to support key ecosystem functions like higher-order predation, which is more prevalent in reserve locations with low human impacts.
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11
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Sherley RB, Botha P, Underhill LG, Ryan PG, van Zyl D, Cockcroft AC, Crawford RJM, Dyer BM, Cook TR. Defining ecologically relevant scales for spatial protection with long-term data on an endangered seabird and local prey availability. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:1312-1321. [PMID: 28248436 DOI: 10.1111/cobi.12923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 02/09/2017] [Accepted: 02/25/2017] [Indexed: 06/06/2023]
Abstract
Human activities are important drivers of marine ecosystem functioning. However, separating the synergistic effects of fishing and environmental variability on the prey base of nontarget predators is difficult, often because prey availability estimates on appropriate scales are lacking. Understanding how prey abundance at different spatial scales links to population change can help integrate the needs of nontarget predators into fisheries management by defining ecologically relevant areas for spatial protection. We investigated the local population response (number of breeders) of the Bank Cormorant (Phalacrocorax neglectus), a range-restricted endangered seabird, to the availability of its prey, the heavily fished west coast rock lobster (Jasus lalandii). Using Bayesian state-space modeled cormorant counts at 3 colonies, 22 years of fisheries-independent data on local lobster abundance, and generalized additive modeling, we determined the spatial scale pertinent to these relationships in areas with different lobster availability. Cormorant numbers responded positively to lobster availability in the regions with intermediate and high abundance but not where regime shifts and fishing pressure had depleted lobster stocks. The relationships were strongest when lobsters 20-30 km offshore of the colony were considered, a distance greater than the Bank Cormorant's foraging range when breeding, and may have been influenced by prey availability for nonbreeding birds, prey switching, or prey ecology. Our results highlight the importance of considering the scale of ecological relationships in marine spatial planning and suggest that designing spatial protection around focal species can benefit marine predators across their full life cycle. We propose the precautionary implementation of small-scale marine protected areas, followed by robust assessment and adaptive-management, to confirm population-level benefits for the cormorants, their prey, and the wider ecosystem, without negative impacts on local fisheries.
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Affiliation(s)
- Richard B Sherley
- Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, U.K
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Philna Botha
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
| | - Les G Underhill
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- Marine Research Institute, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
| | - Peter G Ryan
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
| | - Danie van Zyl
- Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X2, Rogge Bay, 8012, Cape Town, South Africa
| | - Andrew C Cockcroft
- Department of Agriculture, Forestry and Fisheries (DAFF), Private Bag X2, Rogge Bay, 8012, Cape Town, South Africa
| | - Robert J M Crawford
- Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
- Department of Environmental Affairs (DEA), P.O. Box 52126, Cape Town, 8000, South Africa
| | - Bruce M Dyer
- Department of Environmental Affairs (DEA), P.O. Box 52126, Cape Town, 8000, South Africa
| | - Timothée R Cook
- FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch, 7701, South Africa
- Institute of Ecology and Environmental Sciences, Evolutionary Eco-physiology Team, University Pierre et Marie Curie, Bâtiment A-7ème étage, 7 quai, St Bernard, 75005, Paris, France
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12
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Andrello M, Guilhaumon F, Albouy C, Parravicini V, Scholtens J, Verley P, Barange M, Sumaila UR, Manel S, Mouillot D. Global mismatch between fishing dependency and larval supply from marine reserves. Nat Commun 2017; 8:16039. [PMID: 28691710 PMCID: PMC5508853 DOI: 10.1038/ncomms16039] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 05/16/2017] [Indexed: 11/09/2022] Open
Abstract
Marine reserves are viewed as flagship tools to protect exploited species and to contribute to the effective management of coastal fisheries. Yet, the extent to which marine reserves are globally interconnected and able to effectively seed areas, where fisheries are most critical for food and livelihood security is largely unknown. Using a hydrodynamic model of larval dispersal, we predict that most marine reserves are not interconnected by currents and that their potential benefits to fishing areas are presently limited, since countries with high dependency on coastal fisheries receive very little larval supply from marine reserves. This global mismatch could be reversed, however, by placing new marine reserves in areas sufficiently remote to minimize social and economic costs but sufficiently connected through sea currents to seed the most exploited fisheries and endangered ecosystems.
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Affiliation(s)
- Marco Andrello
- EPHE, PSL Research University, CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, Biogéographie et Ecologie des Vertébrés, 1919 route de Mende, 34293 Montpellier, France
| | - François Guilhaumon
- UMR 9190 MARBEC, IRD-CNRS-IFREMER-UM, Université de Montpellier, 34095 Montpellier, France
| | - Camille Albouy
- Landscape Ecology, Institute of Terrestrial Ecosystems, ETH Zürich, 8092 Zürich, Switzerland.,Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland.,IFREMER, Unité Ecologie et Modèles pour l'Halieutique, 44300 Nantes Cedex 3, France
| | - Valeriano Parravicini
- CRIOBE, USR 3278 CNRS-EPHE-UPVD, Labex 'Corail', University of Perpignan, 66860 Perpignan, France
| | - Joeri Scholtens
- MARE Centre for Maritime Research, Amsterdam Institute for Social Science Research, University of Amsterdam, Plantage Muidergracht 14, 1018 Amsterdam, The Netherlands
| | - Philippe Verley
- IRD, UMR AMAP, TA A51/PS2, Montpellier, 05 34398 Cedex, France
| | - Manuel Barange
- Plymouth Marine Laboratory, Prospect Place, PL1 3DH Plymouth, UK.,Food and Agriculture Organization of the UN, Viale delle Terme di Caracalla, 00153 Rome, Italy
| | - U Rashid Sumaila
- Fisheries Economics Research Unit, Institute for Oceans and Fisheries &Liu Institute for Global Studies, the University of British Columbia, Vancouver, Canada V6T 1Z
| | - Stéphanie Manel
- EPHE, PSL Research University, CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, Biogéographie et Ecologie des Vertébrés, 1919 route de Mende, 34293 Montpellier, France
| | - David Mouillot
- UMR 9190 MARBEC, IRD-CNRS-IFREMER-UM, Université de Montpellier, 34095 Montpellier, France.,Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, 4811 Queens Land, Australia
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13
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Graham NAJ, McClanahan TR, MacNeil MA, Wilson SK, Cinner JE, Huchery C, Holmes TH. Human Disruption of Coral Reef Trophic Structure. Curr Biol 2017; 27:231-236. [PMID: 28089513 DOI: 10.1016/j.cub.2016.10.062] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 10/28/2016] [Accepted: 10/31/2016] [Indexed: 11/19/2022]
Abstract
The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass distribution among trophic levels may be disrupted through trophic replacement by alternative organisms in the ecosystem, trophic cascades, and humans preferentially impacting specific trophic levels [4-6]. Using empirical data spanning >250 coral reefs, we show how trophic pyramid shape varies given human-mediated gradients along two orders of magnitude in reef fish biomass. Mean trophic level of the assemblage increased modestly with decreasing biomass, contrary to predictions of fishing down the food web [7]. The mean trophic level pattern is explained by trophic replacement of herbivorous fish by sea urchins at low biomass and the accumulation of slow-growing, large-bodied, herbivorous fish at high biomass. Further, at high biomass, particularly where fishers are not selectively removing higher trophic level individuals, a concave trophic distribution emerges. The concave trophic distribution implies a more direct link between lower and upper trophic levels, which may confer greater energy efficiency. This trophic distribution emerges when community biomass exceeds ∼650 kg/ha, suggesting that fisheries for upper trophic level species will only be supported under lightly fished scenarios.
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Affiliation(s)
- Nicholas A J Graham
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK; Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
| | - Tim R McClanahan
- Wildlife Conservation Society, Marine Programs, Bronx, NY 10460, USA
| | - M Aaron MacNeil
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia; Australian Institute of Marine Science, PMB 3 Townsville MC, Townsville, QLD 4810, Australia; Department of Mathematics and Statistics, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Shaun K Wilson
- Department of Parks and Wildlife, Kensington, Perth, WA 6151, Australia; School of Plant Biology, Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia
| | - Joshua E Cinner
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Cindy Huchery
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia
| | - Thomas H Holmes
- Department of Parks and Wildlife, Kensington, Perth, WA 6151, Australia; School of Plant Biology, Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia
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