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Messinger LN, Stuber EF, Chizinski CJ, Fontaine JJ. Mortality, perception, and scale: Understanding how predation shapes space use in a wild prey population. PLoS One 2019; 14:e0222272. [PMID: 31553753 PMCID: PMC6760887 DOI: 10.1371/journal.pone.0222272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/22/2019] [Indexed: 11/29/2022] Open
Abstract
Attempts to assess behavioral responses of prey to predation risk are often confounded by depredation of prey. Moreover, the scale at which the response of prey is assessed has important implications for discovering how predation risk alters prey behavior. Herein, we assessed space use of wild Ring-necked Pheasants (Phasianus colchicus) in response to spatial and temporal variation in recreational hunting. We radio-marked pheasants and monitored space use at two spatial scales: short-term seasonal home range, and nightly resting locations. Additionally, we considered temporal variation in predation risk by monitoring space use prior to and during the pheasant hunting season. Although we found no change in nightly resting location, pheasants subjected to predation risk expanded their home range and shifted home range location even when invulnerable to predation. Home range formation was plastic, with home ranges expanding and contracting as risk fluctuated before and during the hunting season. Depredation reduced the measured response within the population, obscuring the potential importance of perceived predation risk in shaping prey communities, particularly when not measured at the appropriate scale. By assessing space use of a wild prey population at multiple scales, considering spatial and temporal variation in predation risk, we show that not only does predation risk affect space use, but that the effects at the population level may be challenging to assess when not measured at the appropriate ecological scale because of the direct effects of differential mortality on the same behaviors.
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Affiliation(s)
- Lindsey N. Messinger
- Nebraska Cooperative Fish & Wildlife Research Unit, University of Nebraska–Lincoln, Lincoln, Nebraska, United States of America
- * E-mail:
| | - Erica F. Stuber
- Nebraska Cooperative Fish & Wildlife Research Unit, University of Nebraska–Lincoln, Lincoln, Nebraska, United States of America
| | - Christopher J. Chizinski
- School of Natural Resources, University of Nebraska–Lincoln, Lincoln, Nebraska, United States of America
| | - Joseph J. Fontaine
- Nebraska Cooperative Fish & Wildlife Research Unit, University of Nebraska–Lincoln, Lincoln, Nebraska, United States of America
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2
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Top predators induce habitat shifts in prey within marine protected areas. Oecologia 2019; 190:375-385. [PMID: 31155681 DOI: 10.1007/s00442-019-04421-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 05/19/2019] [Indexed: 10/26/2022]
Abstract
Emerging conservation efforts for the world's large predators may, if successful, restore natural predator-prey interactions. Marine reserves, where large predators tend to be relatively common, offer an experimental manipulation to investigate interactions between large-bodied marine predators and their prey. We hypothesized that southern stingrays-large, long-lived and highly interactive mesopredators-would invest in anti-predator behavior in marine reserves where predatory large sharks, the primary predator of stingrays, are more abundant. Specifically, we predicted southern stingrays in marine reserves would reduce the use of deep forereef habitats in the favor of shallow flats where the risk of shark encounters is lower. Baited remote underwater video was used to survey stingrays and reef sharks in flats and forereef habitats of two reserves and two fished sites in Belize. The interaction between "protection status" and "habitat" was the most important factor determining stingray presence. As predicted, southern stingrays spent more time interacting with baited remote underwater videos in the safer flats habitats, were more likely to have predator-inflicted damage inside reserves, and were less abundant in marine reserves but only in the forereef habitat. These results are consistent with a predation-sensitive habitat shift rather than southern stingray populations being reduced by direct predation from reef sharks. Our study provides evidence that roving predators can induce pronounced habitat shifts in prey that rely on crypsis and refuging, rather than active escape, in high-visibility, heterogeneous marine habitats. Given documented impacts of stingrays on benthic communities it is possible restoration of reef shark populations with reserves could induce reef ecosystem changes through behavior-mediated trophic cascades.
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Gaynor KM, Brown JS, Middleton AD, Power ME, Brashares JS. Landscapes of Fear: Spatial Patterns of Risk Perception and Response. Trends Ecol Evol 2019; 34:355-368. [PMID: 30745252 DOI: 10.1016/j.tree.2019.01.004] [Citation(s) in RCA: 236] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/15/2019] [Accepted: 01/17/2019] [Indexed: 12/20/2022]
Abstract
Animals experience varying levels of predation risk as they navigate heterogeneous landscapes, and behavioral responses to perceived risk can structure ecosystems. The concept of the landscape of fear has recently become central to describing this spatial variation in risk, perception, and response. We present a framework linking the landscape of fear, defined as spatial variation in prey perception of risk, to the underlying physical landscape and predation risk, and to resulting patterns of prey distribution and antipredator behavior. By disambiguating the mechanisms through which prey perceive risk and incorporate fear into decision making, we can better quantify the nonlinear relationship between risk and response and evaluate the relative importance of the landscape of fear across taxa and ecosystems.
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Affiliation(s)
- Kaitlyn M Gaynor
- Department of Environmental Science, Policy, and Management, University of California Berkeley, 130 Mulford Hall #3114, Berkeley, CA 94720, USA. https://twitter.com/@kaitlyngaynor%20
| | - Joel S Brown
- Department of Biological Sciences, University of Illinois at Chicago, 845 West Taylor Street (MC 066), Chicago, IL 60607, USA; Department of Integrated Mathematical Oncology, Moffitt Cancer Center, 12902 Magnolia Dr., Tampa, FL 33612, USA; These authors contributed equally to this work
| | - Arthur D Middleton
- Department of Environmental Science, Policy, and Management, University of California Berkeley, 130 Mulford Hall #3114, Berkeley, CA 94720, USA; These authors contributed equally to this work
| | - Mary E Power
- Department of Integrative Biology, University of California Berkeley, 3060 Valley Life Sciences Building #3140, Berkeley, CA 94720, USA; These authors contributed equally to this work
| | - Justin S Brashares
- Department of Environmental Science, Policy, and Management, University of California Berkeley, 130 Mulford Hall #3114, Berkeley, CA 94720, USA
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4
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Cammen KM, Rasher DB, Steneck RS. Predator recovery, shifting baselines, and the adaptive management challenges they create. Ecosphere 2019. [DOI: 10.1002/ecs2.2579] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Herring supports Northeast Pacific predators and fisheries: Insights from ecosystem modelling and management strategy evaluation. PLoS One 2018; 13:e0196307. [PMID: 29979718 PMCID: PMC6034797 DOI: 10.1371/journal.pone.0196307] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 04/10/2018] [Indexed: 12/02/2022] Open
Abstract
This paper analyzes the trophic role of Pacific herring, the potential consequences of its depletion, and the impacts of alternative herring fishing strategies on a Northeast Pacific food web in relation to precautionary, ecosystem-based management. We used an Ecopath with Ecosim ecosystem model parameterized for northern British Columbia (Canada), employing Ecosim to simulate ecosystem effects of herring stock collapse. The ecological impacts of various herring fishing strategies were investigated with a Management Strategy Evaluation algorithm within Ecosim, accounting for variability in climatic drivers and stock assessment errors. Ecosim results suggest that herring stock collapse would have cascading impacts on much of the pelagic food web. Management Strategy Evaluation results indicate that herring and their predators suffer moderate impacts from the existing British Columbia harvest control rule, although more precautionary management strategies could substantially reduce these impacts. The non-capture spawn-on-kelp fishery, traditionally practiced by many British Columbia and Alaska indigenous peoples, apparently has extremely limited ecological impacts. Our simulations also suggest that adopting a maximum sustainable yield management strategy in Northeast Pacific herring fisheries could generate strong, cascading food web effects. Furthermore, climate shifts, especially when combined with herring stock assessment errors, could strongly reduce the biomasses and resilience of herring and its predators. By clarifying the trophic role of Pacific herring, this study aims to facilitate precautionary fisheries management via evaluation of alternative fishing strategies, and thereby to inform policy tradeoffs among multiple ecological and socioeconomic factors.
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Byrne ME, Cortés E, Vaudo JJ, Harvey GCM, Sampson M, Wetherbee BM, Shivji M. Satellite telemetry reveals higher fishing mortality rates than previously estimated, suggesting overfishing of an apex marine predator. Proc Biol Sci 2018; 284:rspb.2017.0658. [PMID: 28768885 DOI: 10.1098/rspb.2017.0658] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/23/2017] [Indexed: 11/12/2022] Open
Abstract
Overfishing is a primary cause of population declines for many shark species of conservation concern. However, means of obtaining information on fishery interactions and mortality, necessary for the development of successful conservation strategies, are often fisheries-dependent and of questionable quality for many species of commercially exploited pelagic sharks. We used satellite telemetry as a fisheries-independent tool to document fisheries interactions, and quantify fishing mortality of the highly migratory shortfin mako shark (Isurus oxyrinchus) in the western North Atlantic Ocean. Forty satellite-tagged shortfin mako sharks tracked over 3 years entered the Exclusive Economic Zones of 19 countries and were harvested in fisheries of five countries, with 30% of tagged sharks harvested. Our tagging-derived estimates of instantaneous fishing mortality rates (F = 0.19-0.56) were 10-fold higher than previous estimates from fisheries-dependent data (approx. 0.015-0.024), suggesting data used in stock assessments may considerably underestimate fishing mortality. Additionally, our estimates of F were greater than those associated with maximum sustainable yield, suggesting a state of overfishing. This information has direct application to evaluations of stock status and for effective management of populations, and thus satellite tagging studies have potential to provide more accurate estimates of fishing mortality and survival than traditional fisheries-dependent methodology.
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Affiliation(s)
- Michael E Byrne
- Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA
| | - Enric Cortés
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Panama City, FL 32408, USA
| | - Jeremy J Vaudo
- Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA
| | - Guy C McN Harvey
- Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA
| | - Mark Sampson
- Fish Finder Adventures, Ocean City, MD 21842, USA
| | - Bradley M Wetherbee
- Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA.,Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Mahmood Shivji
- Guy Harvey Research Institute, Nova Southeastern University, Dania Beach, FL 33004, USA
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Bizzarro JJ, Carlisle AB, Smith WD, Cortés E. Diet Composition and Trophic Ecology of Northeast Pacific Ocean Sharks. ADVANCES IN MARINE BIOLOGY 2017; 77:111-148. [PMID: 28882212 DOI: 10.1016/bs.amb.2017.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although there is a general perception of sharks as large pelagic, apex predators, most sharks are smaller, meso- and upper-trophic level predators that are associated with the seafloor. Among 73 shark species documented in the eastern North Pacific (ENP), less than half reach maximum lengths >200cm, and 78% occur in demersal or benthic regions of the continental shelf or slope. Most small (≤200cm) species (e.g., houndsharks) and demersal, nearshore juveniles of larger species (e.g., requiem sharks) consume small teleosts and decapod crustaceans, whereas large species in pelagic coastal and oceanic environments feed on large teleosts and squids. Several large, pelagic apex predator species occur in the ENP, but the largest species (i.e., Basking Shark, Whale Shark) consume zooplankton or small nekton. Size-based dietary variability is substantial for many species, and segregation of juvenile and adult foraging habitats also is common (e.g., Horn Shark, Shortfin Mako). Temporal dietary differences are most pronounced for temperate, nearshore species with wide size ranges, and least pronounced for smaller species in extreme latitudes and deep-water regions. Sympatric sharks often occupy various trophic positions, with resource overlap differing by space and time and some sharks serving as prey to other species. Most coastal species remain in the same general region over time and feed opportunistically on variable prey inputs (e.g., season migrations, spawning, or recruitment events), whereas pelagic, oceanic species actively seek hot spots of prey abundance that are spatiotemporally variable. The influence of sharks on ecosystem structure and regulation has been downplayed compared to that of large teleosts species with higher per capita consumption rates (e.g., tunas, billfishes). However, sharks also exert indirect influences on prey populations by causing behavioural changes that may result in restricted ranges and reduced fitness. Except for food web modelling efforts in Alaskan waters, the trophic impacts of sharks are poorly incorporated into current ecosystem approaches to fisheries management in the NEP.
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Affiliation(s)
| | - Aaron B Carlisle
- Hopkins Marine Station of Stanford University, Pacific Grove, CA, United States
| | - Wade D Smith
- University of British Columbia, Institute for the Oceans and Fisheries, Vancouver, BC, Canada
| | - Enric Cortés
- National Marine Fisheries Service, Southeast Fisheries Science Center, Panama City Laboratory, FL, United States
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Towner AV, Leos‐Barajas V, Langrock R, Schick RS, Smale MJ, Kaschke T, Jewell OJD, Papastamatiou YP. Sex‐specific and individual preferences for hunting strategies in white sharks. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12613] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alison V. Towner
- Department of Ichthyology and Fisheries Science Rhodes University PO Box 94 Grahamstown 6140 South Africa
- Dyer Island Conservation Trust Geelbek Street PO Box 78 Keinbaai South Africa
| | | | - Roland Langrock
- Centre for Research into Ecological & Environmental Modelling and School of Mathematics and Statistics University of St Andrews St Andrews KY16 9LZ UK
- Department of Business Administration and Economics Bielefeld University PO Box 100131 33501 Bielefeld Germany
| | - Robert S. Schick
- Centre for Research into Ecological & Environmental Modelling and School of Mathematics and Statistics University of St Andrews St Andrews KY16 9LZ UK
| | - Malcolm J. Smale
- Port Elizabeth Museum at Bayworld PO Box 13147 Humewood 6013 South Africa
- Department of Zoology Nelson Mandela Metropolitan University PO Box 77000 Port Elizabeth South Africa
| | - Tami Kaschke
- Dyer Island Conservation Trust Geelbek Street PO Box 78 Keinbaai South Africa
- Department of Management University of Nebraska Lincoln NEUSA
| | - Oliver J. D. Jewell
- Dyer Island Conservation Trust Geelbek Street PO Box 78 Keinbaai South Africa
- Department of Zoology & Entomology University of Pretoria Private Bag X20 Hatfield Pretoria South Africa
- Department of Spatial Ecology Royal Netherlands Institute for Sea Research (NIOZ) Yerseke 4401 NT The Netherlands
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Kwan CK, Sanford E, Long J. Copper Pollution Increases the Relative Importance of Predation Risk in an Aquatic Food Web. PLoS One 2015; 10:e0133329. [PMID: 26172044 PMCID: PMC4501717 DOI: 10.1371/journal.pone.0133329] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 06/24/2015] [Indexed: 11/18/2022] Open
Abstract
Although the cascading impact of predators depends critically on the relative role of lethal predation and predation risk, we lack an understanding of how human-caused stressors may shift this balance. Emergent evidence suggests that pollution may increase the importance of predator consumptive effects by weakening the effects of fear perceived by prey. However, this oversimplification ignores the possibility that pollution may also alter predator consumptive effects. In particular, contaminants may impair the consumptive effects of predators by altering density-dependent interactions among prey conspecifics. No study has directly compared predator consumptive and non-consumptive effects in polluted versus non-polluted settings. We addressed this issue by using laboratory mesocosms to examine the impact of sublethal doses of copper on tri-trophic interactions among estuarine predator crabs Cancer productus, carnivorous whelk prey Urosalpinx cinerea, and the basal resource barnacles Balanus glandula. We investigated crab consumptive effects (whelks culled without crab chemical cues), non-consumptive effects (whelks not culled with crab chemical cues), and total effects (whelks culled with crab chemical cues) on whelks in copper polluted and non-polluted waters. Realistic copper concentrations suppressed the effects of simulated crab lethal predation (whelk culling) by removing density-dependent feeding by whelks. Specifically, reductions in conspecific density occurring in elevated copper levels did not trigger the normal increase in whelk consumption rates of barnacles. Weakened effects of fear were only observed at extremely high copper levels, suggesting consumptive effects were more sensitive to pollution. Thus, pollution may shape communities by altering the roles of predators and interactions among prey.
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Affiliation(s)
- Christopher Kent Kwan
- Biology Department and Coastal & Marine Institute Laboratory, San Diego State University, San Diego, California, United States of America
- Bodega Marine Laboratory and Department of Evolution and Ecology, University of California Davis, Bodega Bay, California, United States of America
| | - Eric Sanford
- Bodega Marine Laboratory and Department of Evolution and Ecology, University of California Davis, Bodega Bay, California, United States of America
| | - Jeremy Long
- Biology Department and Coastal & Marine Institute Laboratory, San Diego State University, San Diego, California, United States of America
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Gordon CE, Feit A, Grüber J, Letnic M. Mesopredator suppression by an apex predator alleviates the risk of predation perceived by small prey. Proc Biol Sci 2015; 282:rspb.2014.2870. [PMID: 25652837 DOI: 10.1098/rspb.2014.2870] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Predators can impact their prey via consumptive effects that occur through direct killing, and via non-consumptive effects that arise when the behaviour and phenotypes of prey shift in response to the risk of predation. Although predators' consumptive effects can have cascading population-level effects on species at lower trophic levels there is less evidence that predators' non-consumptive effects propagate through ecosystems. Here we provide evidence that suppression of abundance and activity of a mesopredator (the feral cat) by an apex predator (the dingo) has positive effects on both abundance and foraging efficiency of a desert rodent. Then by manipulating predators' access to food patches we further the idea that apex predators provide small prey with refuge from predation by showing that rodents increased their habitat breadth and use of 'risky' food patches where an apex predator was common but mesopredators rare. Our study suggests that apex predators' suppressive effects on mesopredators extend to alleviate both mesopredators' consumptive and non-consumptive effects on prey.
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Affiliation(s)
- Christopher E Gordon
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Anna Feit
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Jennifer Grüber
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Mike Letnic
- Centre for Ecosystem Science, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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Aalto EA, Baskett ML. Quantifying the balance between bycatch and predator or competitor release for nontarget species. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2013; 23:972-983. [PMID: 23967569 DOI: 10.1890/12-1316.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
If a species is bycatch in a fishery targeted at its competitor or predator, it experiences both direct anthropogenic mortality and indirect positive effects through species interactions. If the species involved interact strongly, the release from competition or predation can counteract or exceed the negative effects of bycatch. We used a set of two- and three-species community modules to analyze the relative importance of species interactions when modeling the overall effect of harvest with bycatch on a nontarget species. To measure the trade-off between direct mortality and indirect positive effects, we developed a "bycatch transition point" metric to determine, for different scenarios, what levels of bycatch shift overall harvest impact from positive to negative. Under strong direct competition with a targeted competitor, release from competition due to harvest leads to a net increase in abundance even under moderate levels of bycatch. For a three-species model with a shared obligate predator, the release from apparent competition exceeds direct competitive release and outweighs the decrease from bycatch mortality under a wide range of parameters. Therefore, in communities where a shared predator forms a strong link between the target and nontarget species, the effects of indirect interactions on populations can be larger than those of direct interactions. The bycatch transition point metric can be used for tightly linked species to evaluate the relative strengths of positive indirect effects and negative anthropogenic impacts such as bycatch, habitat degradation, and introduction of invasive species.
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Affiliation(s)
- Emilius A Aalto
- Department of Environmental Science and Policy, 1 Shields Avenue, University of California, Davis, California 95616, USA.
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12
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Damalas D, Megalofonou P. Occurrences of large sharks in the open waters of the southeastern Mediterranean Sea. J NAT HIST 2012. [DOI: 10.1080/00222933.2012.716864] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Courtney DL, Foy R. Pacific sleeper shark Somniosus pacificus trophic ecology in the eastern North Pacific Ocean inferred from nitrogen and carbon stable-isotope ratios and diet. JOURNAL OF FISH BIOLOGY 2012; 80:1508-1545. [PMID: 22497395 DOI: 10.1111/j.1095-8649.2012.03261.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Stable-isotope ratios of nitrogen (δ¹⁵N) and lipid-normalized carbon (δ¹³C') were used to examine geographic and ontogenetic variability in the trophic ecology of a high latitude benthopelagic elasmobranch, the Pacific sleeper shark Somniosus pacificus. Mean muscle tissue δ¹³C' values of S. pacificus differed significantly among geographic regions of the eastern North Pacific Ocean. Linear models identified significant ontogenetic and geographic variability in muscle tissue δ¹⁵N values of S. pacificus. The trophic position of S. pacificus in the eastern North Pacific Ocean estimated here from previously published stomach-content data (4·3) was within the range of S. pacificus trophic position predicted from a linear model of S. pacificus muscle tissue δ¹⁵N (3·3-5·7) for fish of the same mean total length (L(T) ; 201·5 cm), but uncertainty in predicted trophic position was very high (95% prediction intervals ranged from 2·9 to 6·4). The relative trophic position of S. pacificus determined here from a literature review of δ¹⁵N by taxa in the eastern North Pacific Ocean was also lower than would be expected based on stomach-content data alone when compared to fishes, squid and filter feeding whales. Stable-isotope analysis revealed wider variability in the feeding ecology of S. pacificus in the eastern North Pacific Ocean than shown by diet data alone, and expanded previous conclusions drawn from analyses of stomach-content data to regional and temporal scales meaningful for fisheries management.
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Affiliation(s)
- D L Courtney
- School of Fisheries and Ocean Sciences, Juneau Center, University of Alaska Fairbanks, 17101 Point Lena Loop Road, Juneau, AK 99801, USA.
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Papastamatiou YP, Lowe CG. An analytical and hypothesis-driven approach to elasmobranch movement studies. JOURNAL OF FISH BIOLOGY 2012; 80:1342-1360. [PMID: 22497387 DOI: 10.1111/j.1095-8649.2012.03232.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The study of elasmobranch movements has increased steadily since the early 1970s. A great deal is now known about the horizontal and vertical movements of many elasmobranch species over multiple spatial and temporal scales. These studies illustrate that many species share certain behaviours such as diel shifts in habitat (both horizontal and vertical), continuous yo-yo bounce diving and in many cases, seasonal migrations. Hypothesis-driven studies explaining these behaviours or utilizing an eco-physiological predictive framework are, however, relatively rare. In this review, the descriptive and hypothesis-driven studies of elasmobranch movements are discussed, in addition to some of the analytical tools that can be used to generate or test predictions. There are many tools and analytical techniques available which are not currently being utilized for most studies of elasmobranch movements. With the constant improvement in technology and statistical techniques, the development of hypothesis-driven studies of elasmobranch movements should continue to increase.
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Affiliation(s)
- Y P Papastamatiou
- Florida Museum of Natural History, University of Florida, Museum Road & Newell, Gainesville, FL 32611, USA.
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15
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Barnett A, Semmens JM. Sequential movement into coastal habitats and high spatial overlap of predator and prey suggest high predation pressure in protected areas. OIKOS 2012. [DOI: 10.1111/j.1600-0706.2011.20000.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Wirsing AJ, Heithaus MR, Dill LM. Predator-induced modifications to diving behavior vary with foraging mode. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18844.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Madin EMP, Gaines SD, Warner RR. Field evidence for pervasive indirect effects of fishing on prey foraging behavior. Ecology 2010; 91:3563-71. [PMID: 21302828 DOI: 10.1890/09-2174.1] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Elizabeth M. P. Madin
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106 USA
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales 2019 Australia
| | - Steven D. Gaines
- Marine Science Institute, University of California, Santa Barbara, California 93106 USA
- Bren School of Environmental Science and Management, University of California, Santa Barbara, California 93106 USA
| | - Robert R. Warner
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106 USA
- Marine Science Institute, University of California, Santa Barbara, California 93106 USA
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18
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Madin EMP, Gaines SD, Madin JS, Warner RR. Fishing Indirectly Structures Macroalgal Assemblages by Altering Herbivore Behavior. Am Nat 2010; 176:785-801. [PMID: 20961223 DOI: 10.1086/657039] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Elizabeth M P Madin
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, USA.
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Abstract
There is growing recognition of the important roles played by predators in regulating ecosystems and sustaining biodiversity. Much attention has focused on the consequences of predator-regulation of herbivore populations, and associated trophic cascades. However apex predators may also control smaller 'mesopredators' through intraguild interactions. Removal of apex predators can result in changes to intraguild interactions and outbreaks of mesopredators ('mesopredator release'), leading in turn to increased predation on smaller prey. Here we provide a review and synthesis of studies of predator interactions, mesopredator release and their impacts on biodiversity. Mesopredator suppression by apex predators is widespread geographically and taxonomically. Apex predators suppress mesopredators both by killing them, or instilling fear, which motivates changes in behaviour and habitat use that limit mesopredator distribution and abundance. Changes in the abundance of apex predators may have disproportionate (up to fourfold) effects on mesopredator abundance. Outcomes of interactions between predators may however vary with resource availability, habitat complexity and the complexity of predator communities. There is potential for the restoration of apex predators to have benefits for biodiversity conservation through moderation of the impacts of mesopredators on their prey, but this requires a whole-ecosystem view to avoid unforeseen negative effects. 'Nothing has changed since I began. My eye has permitted no change. I am going to keep things like this.' From 'Hawk Roosting', by Ted Hughes.
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Affiliation(s)
- Euan G Ritchie
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia.
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Predicting synergistic effects of resources and predators on foraging decisions by juvenile Steller sea lions. Oecologia 2008; 158:775-86. [DOI: 10.1007/s00442-008-1189-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 10/01/2008] [Indexed: 10/21/2022]
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Creel S, Winnie JA, Christianson D, Liley S. Time and space in general models of antipredator response: tests with wolves and elk. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2008.07.006] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Heithaus MR, Frid A, Wirsing AJ, Worm B. Predicting ecological consequences of marine top predator declines. Trends Ecol Evol 2008; 23:202-10. [PMID: 18308421 DOI: 10.1016/j.tree.2008.01.003] [Citation(s) in RCA: 452] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 01/09/2008] [Accepted: 01/10/2008] [Indexed: 11/28/2022]
Affiliation(s)
- Michael R Heithaus
- Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA.
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Effects of body size, age and maturity stage on diet in a large shark: ecological and applied implications. Ecol Res 2008. [DOI: 10.1007/s11284-008-0487-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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