The functioning of marine ecosystems: a fisheries perspective.

There is considerable evidence that environmental variability plays a major role in controlling abundance and distribution of marine populations and that fisheries alter ecosystem functioning and state. This overviewdocuments emergent, i.e. visible to us as observers, ecosystem-level ecological patterns and addresses important questions regarding the exploitation of marine resources. Do marine ecosystems function differently from terrestrial systems? Do multiple stable states exist in marine ecosystems? Does removal of top predators in marine ecosystems result in fundamental changes in the plankton communities (top-down ‘trophic cascades’), as observed in lakes? Alternatively, are marine ecosystems characterized by bottom-up control such that fishing predatory fish does not disturb community structure and function? Does heavy exploitation of forage species, such as anchovies and sardines, cause changes in the functioning of upwelling ecosystems? The key to answering these questions and exploring whether general principles apply lies in understanding the energy flow within the ecosystems. The chapter reviews different types of energy flow in marine ecosystems, i.e. bottom-up control (control by primary producers), top-down control (control by predators) and wasp-waist control (control by numerically dominant species). No general theory can yet be ascribed to the functioning of marine ecosystems. Ecological understanding and models of ecosystem functioning are provisional and subject to change, and common sense is not sufficient when studying complex dynamic systems. However, tentative and partial generalizations are proposed, namely that bottom-up control predominates; top-down control plays a role in dampening ecosystem-level fluctuations; trophic cascades seldom occur; and wasp-waist control is most probable in upwelling systems. Moreover, alternation and large-scale synchronized fluctuations in fish stocks, stability of fish communities and emergent features such as size spectra are potentially important patterns when assessing states and changes in marine ecosystems. New and meaningful indicators, derived from our current understanding of marine ecosystem functioning, can be used to assess the impact of fisheries and to promote responsible fisheries in marine ecosystems.

[1]  J. Estes,et al.  Sea Otters and Kelp Forests in Alaska: Generality and Variation in a Community Ecological Paradigm , 1995 .

[2]  James H. Brown,et al.  The Report of the Ecological Society of America Committee on the Scientific Basis for Ecosystem Management , 1996 .

[3]  Micheli,et al.  Eutrophication, Fisheries, and Consumer-Resource Dynamics in Marine Pelagic Ecosystems. , 1999, Science.

[4]  Olesen Nj Clearance potential of jellyfish Aurelia aurita, and predation impact on zooplankton in a shallow cove , 1995 .

[5]  J. Castilla,et al.  Challenges in the Quest for Keystones , 1996 .

[6]  C. V. Lingen Effect of particle size and concentration on the feeding behaviour of adult pilchard Sardinops sagax , 1994 .

[7]  N. Aebischer,et al.  Parallel long-term trends across four marine trophic levels and weather , 1990, Nature.

[8]  R. Paine Food webs : linkage, interaction strength and community infrastructure , 1980 .

[9]  Tinker,et al.  Killer whale predation on sea otters linking oceanic and nearshore ecosystems , 1998, Science.

[10]  Steven R. Hare,et al.  Decadal-scale regime shifts in the large marine ecosystems of the North-east Pacific: a case for historical science , 1994 .

[11]  A. Tansley The Use and Abuse of Vegetational Concepts and Terms , 1935 .

[12]  L. J. Shannnon,et al.  Comparing Models of Trophic Flows in the Northern and Southern Benguela Upwelling Systems During the 1980s , 1999 .

[13]  R. May,et al.  Stability and Complexity in Model Ecosystems , 1976, IEEE Transactions on Systems, Man, and Cybernetics.

[14]  R. Steneck Human influences on coastal ecosystems: does overfishing create trophic cascades? , 1998, Trends in ecology & evolution.

[15]  B. E. Skud Dominance in Fishes: The Relation Between Environment and Abundance , 1982, Science.

[16]  N. Bax The significance and prediction of predation in marine fisheries , 1998 .

[17]  David Claessen,et al.  Dwarfs and Giants: Cannibalism and Competition in Size‐Structured Populations , 2000, The American Naturalist.

[18]  P. Verity Why is relating plankton community structure to pelagic production so problematic , 1998 .

[19]  D. Cayan,et al.  Climate-Ocean Variability and Ecosystem Response in the Northeast Pacific , 1998, Science.

[20]  A. Bakun Patterns in the ocean: Ocean processes and marine population dynamics , 1996 .

[21]  R. O'Neill,et al.  The value of the world's ecosystem services and natural capital , 1997, Nature.

[22]  Steven R. Hare,et al.  Effects of interdecadal climate variability on the oceanic ecosystems of the NE Pacific , 1998 .

[23]  Stephen J. Hall,et al.  The Effects Of Fishing On Mariane Ecosystems And Communities , 1998 .

[24]  I. Hampton The role of acoustic surveys in the assessment of pelagic fish resources on the South African continental shelf , 1992 .

[25]  Chase Are there real differences among aquatic and terrestrial food webs? , 2000, Trends in ecology & evolution.

[26]  P. Cury,et al.  Hunting became a secondary activity 2000 years ago: marine fishing did the same in 2021 , 2001 .

[27]  V. Christensen Indicators for marine ecosystems affected by fisheries , 2000 .

[28]  V. Smetácek Revolution in the ocean , 1999, Nature.

[29]  M. Sissenwine Why Do Fish Populations Vary , 1984 .

[30]  John H. Lawton,et al.  Redundancy in Ecosystems , 1994 .

[31]  K. McCann The diversity–stability debate , 2000, Nature.

[32]  Michel J. Kaiser,et al.  The effects of fishing on marine ecosystems , 1998 .

[33]  R. Paine Food Web Complexity and Species Diversity , 1966, The American Naturalist.

[34]  M. Hunter,et al.  Playing Chutes and Ladders: Heterogeneity and the Relative Roles of Bottom‐Up and Top‐Down Forces in Natural Communities , 1992, Ecology.

[35]  R. W. Sheldon,et al.  Structure of Pelagic Food Chain and Relationship Between Plankton and Fish Production , 1977 .

[36]  R. Chambers,et al.  Early Life History and Recruitment in Fish Populations , 1997, Chapman & Hall Fish and Fisheries Series.

[37]  P. Yodzis,et al.  Must top predators be culled for the sake of fisheries? , 2001, Trends in ecology & evolution.

[38]  Claude Roy,et al.  Optimal Environmental Window and Pelagic Fish Recruitment Success in Upwelling Areas , 1989 .

[39]  J. Castilla,et al.  The management of fisheries and marine ecosystems , 1997 .

[40]  D. Pauly,et al.  Ecosystem Considerations and the Limitations of Ecosystem Models in Fisheries Management: Insights from the Bering Sea , 1999 .

[41]  Sanford,et al.  Regulation of keystone predation by small changes in ocean temperature , 1999, Science.

[42]  Claude Roy,et al.  Worldwide large-scale fluctuations of sardine and anchovy populations , 1999 .

[43]  A. Mcintyre Forage Fishes in Marine Ecosystems: University of Alaska Sea Grant, AK-SG-97-01, Fairbanks, 1997, 816 pages, hardback, ISBN 1-56612-049-7 ($40) , 2001 .

[44]  Keith Sainsbury,et al.  Impact of fishing on size composition and diversity of demersal fish communities , 2000 .

[45]  Colin W. Clark,et al.  Management of Multispecies Fisheries , 1979, Science.

[46]  M. Sinclair Marine Populations: An Essay on Population Regulation and Speciation , 1988 .

[47]  R. May Population biology: Crash tests for real , 1999, Nature.

[48]  Cole,et al.  Trophic cascades revealed in diverse ecosystems. , 1999, Trends in ecology & evolution.

[49]  P. Shelton,et al.  Partitioning of a goby resource amongst four avian predators and evidence for altered trophic flow in the pelagic community of an intense, perennial upwelling system , 1985 .

[50]  N. Graham,et al.  Physical and biological consequences of a climate event in the central North Pacific , 1994 .

[51]  S. Murawski Can We Manage Our Multispecies Fisheries , 1991 .

[52]  K. Bjorndal,et al.  Historical Overfishing and the Recent Collapse of Coastal Ecosystems , 2001, Science.

[53]  Astrid Jarre,et al.  Small pelagics in upwelling systems: patterns of interaction and structural changes in "wasp-waist" ecosystems , 2000 .

[54]  Rainer Froese,et al.  Fishing Down Aquatic Food Webs , 2000 .

[55]  J. Isaacs,et al.  ABUNDANCE OF PELAGIC FISH DURING THE 19TH AND 20TH CENTURIES AS RECORDED IN ANAEROBIC SEDIMENT OFF THE CALIFORNIAS , 1974 .

[56]  P. Cury,et al.  The recruitment of the Chilean sardine ( Sardinops sagax ) and the "optimal environmental window" , 1998 .

[57]  A. Bakun,et al.  'School-mix feedback': A different way to think about low frequency variability in large mobile fish populations , 2001 .

[58]  Y. Shin,et al.  Exploring fish community dynamics through size dependent trophic interactions using a spatialized individual based model , 2001 .

[59]  Villy Christensen,et al.  Competition between fisheries and marine mammals for prey and primary production in the Pacific Ocean , 1997 .

[60]  P. A. Larkin Concepts and issues in marine ecosystem management , 1996, Reviews in Fish Biology and Fisheries.

[61]  Lennart Persson,et al.  Size-dependent predation in piscivores : interactions between predator foraging and prey avoidance abilities , 1999 .

[62]  J. Gulland Why do fish numbers vary , 1982 .

[63]  R. Beverton Small marine pelagic fish and the threat of fishing; are they endangered? , 1990 .

[64]  J. Roughgarden,et al.  Dynamics of Single Species , 1984 .

[65]  Y. Ishida,et al.  Trophic relations in the subarctic North Pacific ecosystem : possible feeding effect from pink salmon , 1997 .

[66]  S. Neuenfeldt,et al.  Trophodynamic control on recruitment success in Baltic cod: the influence of cannibalism , 2000 .

[67]  Bakun,et al.  The “school trap”: a mechanism promoting large-amplitude out-of-phase population oscillations of small pelagic fish species , 1999 .

[68]  C. Walters,et al.  Keystone predators in the Central Pacific , 1999 .

[69]  Donald R. Strong,et al.  ARE TROPHIC CASCADES ALL WET? DIFFERENTIATION AND DONOR-CONTROL IN SPECIOSE ECOSYSTEMS' , 1992 .

[70]  K. Frank,et al.  Fisheries Ecology in the Context of Ecological and Evolutionary Theory , 1994 .

[71]  S. Garcia,et al.  Sustainability reference systems and indicators for responsible marine capture fisheries: a review of concepts and elements for a set of guidelines , 2000 .

[72]  D. Doak,et al.  The Keystone-Species Concept in Ecology and ConservationManagement and policy must explicitly consider the complexity of interactions in natural systems , 1993 .

[73]  P. Cury Obstinate Nature: An Ecology of Individuals. Thoughts on Reproductive Behavior and Biodiversity , 1994 .

[74]  M. Sinclair Prologue. Recruitment in fish populations: the paradigm shift generated by ICES Committee A , 1997 .

[75]  D. Pauly,et al.  Patterns and propensities in reproduction and growth of marine fishes , 2000, Ecological Research.

[76]  K. Brink,et al.  Benguela trophic functioning , 2004, Reviews in Fish Biology and Fisheries.

[77]  J. Jahncke,et al.  Comparison of trends in abundance of guano-producing seabirds in Peru and Southern Africa , 1999 .

[78]  T. Hayward,et al.  Pacific Ocean climate change: atmospheric forcing, ocean circulation and ecosystem response. , 1997, Trends in ecology & evolution.

[79]  J. Smol,et al.  Impacts of climatic change and fishing on Pacific salmon abundance over the past 300 years. , 2000, Science.