DOCSLIB.ORG

Ecopath 25 Years Conference Proceedings: Extended Abstracts

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ecopath 25 Years Conference Proceedings: Extended Abstracts ISSN 1198-6727 Fisheries Centre Research Reports 2009 Volume 17 Number 3 Ecopath 25 Years Conference Proceedings: Extended Abstracts Fisheries Centre, University of British Columbia, Canada Ecopath 25 Years Conference Proceedings: Extended Abstracts Edited by M.L. Deng Palomares Lyne Morissette Andres Cisneros-Montemayor Divya Varkey Marta Coll Chiara Piroddi Fisheries Centre Research Reports 17(3) 167 pages © published 2009 by The Fisheries Centre, University of British Columbia 2202 Main Mall Vancouver, B.C., Canada, V6T 1Z4 ISSN 1198-6727 Fisheries Centre Research Reports 17(3) 2009 ECOPATH 25 YEARS CONFERENCE PROCEEDINGS: EXTENDED ABSTRACTS edited by M.L. Deng Palomares Lyne Morissette Andres Cisneros-Montemayor Divya Varkey Marta Coll Chiara Piroddi CONTENTS Page FOREWORD ............................................................................................................................................. 1 WELCOME NOTE ......................................................................................................................................2 THE ORGANIZING COMMITTEE ...................................................................................................................3 ACKNOWLEDGEMENTS ..............................................................................................................................6 ON BEING GREEN..................................................................................................................................... 7 PROGRAM: ORAL PRESENTATIONS ..............................................................................................................8 LIST OF POSTER PRESENTATIONS .............................................................................................................. 12 KEYNOTE SPEAKERS ............................................................................................................................... 14 OPENING SESSION .................................................................................................................................. 16 The origins of Ecopath.................................................................................................................................................... 16 Jeffrey Polovina .......................................................................................................................................................... 16 Ecopath: from the French Frigate Shoals to the Philippines and to UBC ................................................................... 17 Daniel Pauly................................................................................................................................................................ 17 FISHERIES APPLICATIONS: ORAL PRESENTATIONS .......................................................................................20 Foraging arena theory ...................................................................................................................................................20 Carl J. Walters, Villy Christensen, Robert Ahrens ....................................................................................................20 EcoTroph: a new tool in the EwE family....................................................................................................................... 21 Didier Gascuel, Melen Leclerc, Audrey Valls, Sylvie Guénette................................................................................. 21 Exploring fisheries strategies for ecosystem-based management in the East China Sea.........................................23 Jiang Hong, Cheng He Qin, Francisco Arreguín-Sánchez........................................................................................23 Ecological effect of moonjelly, Aurelia aurita, removal in the Sea of Suo-Nada, Seto Inland Sea, Japan ...............25 Shingo Watari, Hiromu Zenitani, Keisuke Yamamoto, Naoaki Kono......................................................................25 Capturing significant coral reef ecosystem and fishery changes in Bolinao, Philippines (1997-2008) using Ecopath with Ecosim.......................................................................................................................................................27 Rollan C. Geronimo, Porfirio M. Aliño ......................................................................................................................27 Fisheries in Baja California Sur: a trophic-based analysis of management scenarios .............................................29 Andres M. Cisneros-Montemayor, Villy Christensen, Ussif Rashid Sumaila, Francisco Arreguín-Sánchez..........29 Impact of fishing and climate on the Celtic Sea and the Bay of Biscay....................................................................... 31 Sylvie Guénette, Didier Gascuel................................................................................................................................. 31 FISHERIES APPLICATIONS: POSTER PRESENTATIONS ................................................................................... 33 Recovery scenarios of a highly exploited species, Merluccius merluccius, in the NW Mediterranean Sea ..............33 Giovanni Vargiu, Marta Coll, Isabel Palomera, Sergi Tudela ...................................................................................33 On the transfer payment of the fishery fuel subsidies in China ...................................................................................35 Cheng He Qin, Jiang Hong.........................................................................................................................................35 Vulnerability to fishing of the Central Gulf of California ecosystem...........................................................................37 Francisco Arreguín-Sánchez, Luis A. Salcido-Guevara.............................................................................................37 Effects of local fisheries and ocean productivity on the Northeastern Ionian Sea ecosystem ...................................39 Chiara Piroddi, Giovanni Bearzi, Villy Christensen ..................................................................................................39 Trophodynamic modelling of the eastern shelf and slope of the South East Fishery ................................................. 41 Catherine Bulman, Scott Condie, Neil Klaer, Dianne Furlani, Madeleine Cahill, Simon Goldsworthy, Ian Knuckey....................................................................................................................................................................... 41 The impacts of longline fishery on the pelagic ecosystem in the eastern Taiwan waters......................................... 44 Chien-Pang Chin, Chi-Lu Sun, Kwang-Ming Liu ..................................................................................................... 44 Introducing ecosystem-based management in the Gulf of Thailand.......................................................................... 46 Ratanawalee Poonsawat, Mala Supongpan, Villy Christensen................................................................................ 46 Trophic analysis of Lake Awassa (Ethiopia) using a mass-balanced Ecopath model ...............................................47 Tadesse Fetahi, Seyoum Mengistou...........................................................................................................................47 SPATIAL ANALYSIS: ORAL PRESENTATIONS ................................................................................................ 49 Ecospace: has its time come? ........................................................................................................................................ 49 Steve Mackinson ........................................................................................................................................................ 49 Evaluation of the usefulness of Marine Protected Areas (MPAs) for management of recovery of fish stocks and ecosystems in the North Sea .......................................................................................................................................... 50 Georgi M. Daskalov, Steve Mackinson, Hong Q. Cheng, John K. Pinnegar............................................................50 Modelling spatial closures and fishing effort restrictions in Jurien Bay, Western Australia: a case study of the western rock lobster (Panulirus cygnus) fishery ..........................................................................................................52 Hector M. Lozano-Montes, Russ Babcock, Neil R. Loneragan.................................................................................52 A trophic model to simulate the combined effect of artisanal and recreational fisheries on a Mediterranean ecosystem: the Bonifacio Straits Natural Reserve (Corsica, France)..........................................................................55 Camille Albouy, François Le Loc’h, Jean Michel Culioli, David Mouillot................................................................55 Trophic modeling of a temperate marine ecosystem throughout marine reserve protection in New Zealand .......57 Tyler D. Eddy, Jonathan P.A. Gardner ......................................................................................................................57 Estimating the carrying capacity of monk seals using the French Frigate
Load more

Recommended publications
  • Dyhia Belhabib, Sarah Harper, Dirk Zeller and Daniel Pauly
    Reconstruction of marine fisheries catches for Morocco-Belhabib et al. 23 RECONSTRUCTION OF MARINE FISHERIES CATCHES FOR MOROCOO (NORTH, CENTRAL AND SOUTH), 1950-20101 Dyhia Belhabib, Sarah Harper, Dirk Zeller and Daniel Pauly Sea Around Us Project, Fisheries Centre, University of British Columbia 2202 Main Mall, Vancouver, V6T 1Z4, Canada [email protected]; [email protected]; [email protected]; [email protected] ABSTRACT Fisheries catches in the Moroccan Exclusive Economic Zone (EEZ), including the Atlantic and Mediterranean areas, were reconstructed to include commercial small-scale, commercial large-scale, illegal and unregulated fisheries, non-commercial recreational and subsistence fisheries, and foreign catches in both EEZ areas. Estimated domestic catches suggest that Moroccan data supplied to FAO are less reliable than they should be, with over 41.5% of catches being unreported. This study also shows that 25.4 million tonnes of catches were taken from the southern EEZ area, which contributed to 52% of the Moroccan catch estimated at 48.4 million tonnes. This illustrates not only that Morocco needs to improve its fisheries monitoring system to include small-scale fishing and unregulated fishing, but also questions the impacts of the fishing access agreements signed by Morocco on the local economy and fisheries sustainability, particularly in the southern area where most foreign catches are taken. INTRODUCTION Morocco is located in North Africa, west of Algeria and shares the Alboran Sea with Spain in the North. On the West African coast, Morocco, including the former Spanish Sahara, ranges from Tangier (36° N) to Lagouira (20° N) on Cape Blanc, which is one of the richest fishing areas in the world due to the sustained east central Atlantic upwelling (Porter 1997; Anon.
    [Show full text]
  • Glossary Glossary
    Glossary Glossary Albedo A measure of an object’s reflectivity. A pure white reflecting surface has an albedo of 1.0 (100%). A pitch-black, nonreflecting surface has an albedo of 0.0. The Moon is a fairly dark object with a combined albedo of 0.07 (reflecting 7% of the sunlight that falls upon it). The albedo range of the lunar maria is between 0.05 and 0.08. The brighter highlands have an albedo range from 0.09 to 0.15. Anorthosite Rocks rich in the mineral feldspar, making up much of the Moon’s bright highland regions. Aperture The diameter of a telescope’s objective lens or primary mirror. Apogee The point in the Moon’s orbit where it is furthest from the Earth. At apogee, the Moon can reach a maximum distance of 406,700 km from the Earth. Apollo The manned lunar program of the United States. Between July 1969 and December 1972, six Apollo missions landed on the Moon, allowing a total of 12 astronauts to explore its surface. Asteroid A minor planet. A large solid body of rock in orbit around the Sun. Banded crater A crater that displays dusky linear tracts on its inner walls and/or floor. 250 Basalt A dark, fine-grained volcanic rock, low in silicon, with a low viscosity. Basaltic material fills many of the Moon’s major basins, especially on the near side. Glossary Basin A very large circular impact structure (usually comprising multiple concentric rings) that usually displays some degree of flooding with lava. The largest and most conspicuous lava- flooded basins on the Moon are found on the near side, and most are filled to their outer edges with mare basalts.
    [Show full text]
  • Are Deep-Sea Fisheries Sustainable? a Summary of New Scientific Analysis: Norse, E.A., S
    RESEARCH SERIES AUGUST 2011 High biological vulnerability and economic incentives challenge the viability of deep-sea fisheries. ARE DEEP-SEA FISHERIES SUSTAINABLE? A SUMMARY OF NEW SCIENTIFIC AnaLYSIS: Norse, E.A., S. Brooke, W.W.L. Cheung, M.R. Clark, I. Ekeland, R. Froese, K.M. Gjerde, R.L. Haedrich, S.S. Heppell, T. Morato, L.E. Morgan, D. Pauly, U. R. Sumaila and R. Watson. 2012. Sustainability of Deep-sea Fisheries. Marine Policy 36(2): 307–320. AS COASTAL FISHERIES have declined around the world, fishermen have expanded their operations beyond exclusive economic zones (EEZs) to the high seas beyond EEZs, including the deep sea. Although the deep sea is the largest yet least ecologically productive part of the ocean, seamounts and other habitats can host significant amounts of some deep- sea fish species, especially when they aggregate to breed and feed. Many deep-sea fishes are slow to reproduce, or produce young only sporadically, however, making commercial fisheries unsustainable. Dr. Elliott Norse of the Marine Conservation Institute and a multidisciplinary team of co-authors analyzed data on fishes, fisheries and deep-sea biology and assessed key economic drivers and international laws to determine whether deep-sea commercial fishing could be sustainable. Ultimately, the authors conclude that most deep-sea fisheries are unsustainable, especially on the high seas. This Lenfest Research Series report is a summary of the scientists’ findings. DEEP-SEA FISHERIES As coastal fisheries have declined, fishing in the deep sea has increased. Technological advances have enabled fishing vessels to travel further from shore and locate aggregations of fish in depths that were unreachable years ago (see graphic).
    [Show full text]
  • Fisheries Centre Research Reports 2006 Volume 14 Number 6
    ISSN 1198-6727 Fisheries Centre Research Reports 2006 Volume 14 Number 6 CATCHING MORE BAIT: A BOTTOM-UP RE-ESTIMATION OF GLOBAL FISHERIES SUBSIDIES Fisheries Centre, University of British Columbia, Canada CATCHING MORE BAIT: A BOTTOM-UP RE-ESTIMATION OF GLOBAL FISHERIES SUBSIDIES edited by Ussif Rashid Sumaila and Daniel Pauly Fisheries Centre Research Reports 14(6) 114 pages © published 2006 by The Fisheries Centre, University of British Columbia 2202 Main Mall Vancouver, B.C., Canada, V6T 1Z4 ISSN 1198-6727 Fisheries Centre Research Reports 14(6) 2006 CATCHING MORE BAIT: A BOTTOM-UP RE-ESTIMATION OF GLOBAL FISHERIES SUBSIDIES edited by Ussif Rashid Sumaila and Daniel Pauly CONTENTS Page DIRECTOR’S FOREWORD .................................................................................................................................... 1 EXECUTIVE SUMMARY ....................................................................................................................................... 2 LIST OF ACRONYMS ............................................................................................................................................ 3 CHAPTER 1 THE NATURE AND MAGNITUDE OF GLOBAL NON-FUEL FISHERIES SUBSIDIES KHAN, A. S., U. R. SUMAILA, R. WATSON, G. MUNRO AND D. PAULY............................................. 5 CHAPTER 2 FUEL SUBSIDIES TO GLOBAL FISHERIES SUMAILA, U.R., L. TEH, R. WATSON, P. TYEDMERS AND D. PAULY .............................................. 38 CHAPTER 3 SUBSIDIES TO HIGH SEAS BOTTOM TRAWL FLEETS SUMAILA,
    [Show full text]
  • Sky and Telescope
    SkyandTelescope.com The Lunar 100 By Charles A. Wood Just about every telescope user is familiar with French comet hunter Charles Messier's catalog of fuzzy objects. Messier's 18th-century listing of 109 galaxies, clusters, and nebulae contains some of the largest, brightest, and most visually interesting deep-sky treasures visible from the Northern Hemisphere. Little wonder that observing all the M objects is regarded as a virtual rite of passage for amateur astronomers. But the night sky offers an object that is larger, brighter, and more visually captivating than anything on Messier's list: the Moon. Yet many backyard astronomers never go beyond the astro-tourist stage to acquire the knowledge and understanding necessary to really appreciate what they're looking at, and how magnificent and amazing it truly is. Perhaps this is because after they identify a few of the Moon's most conspicuous features, many amateurs don't know where Many Lunar 100 selections are plainly visible in this image of the full Moon, while others require to look next. a more detailed view, different illumination, or favorable libration. North is up. S&T: Gary The Lunar 100 list is an attempt to provide Moon lovers with Seronik something akin to what deep-sky observers enjoy with the Messier catalog: a selection of telescopic sights to ignite interest and enhance understanding. Presented here is a selection of the Moon's 100 most interesting regions, craters, basins, mountains, rilles, and domes. I challenge observers to find and observe them all and, more important, to consider what each feature tells us about lunar and Earth history.
    [Show full text]
  • Impact on Local Fishermen on Inhaca Island, Mozambique, Due to Introduction of a New Marine Reserve
    Impact on local fishermen on Inhaca Island, Mozambique, due to introduction of a new marine reserve – with focus on fish catches Caroline Enebrand Uppsats för avläggande av naturvetenskaplig kandidatexamen i Miljövetenskap 15 hp Institutionen för biologi och miljövetenskap Göteborgs universitet Juni 2012 Abstract In July 2009 the government of Mozambique approved a new Marine Protected Area, the Ponta do Ouro Partial Marine Reserve (PPMR). The reserve extends from Ponta do Ouro (in the south of Mozambique) up to the mouth of Maputo River near the capital Maputo. Recently the Ministry of Tourism wrote a management plan for the reserve. Along with the new management come new restrictions, which can affect local communities depending on the marine resources. As an example it will be prohibited to fish demersal fish and use vertical jigs. This report will focus on the area of Inhaca Island, which is located in the Indian Ocean within the area of the new reserve. The main purpose of this study was to analyze how the artisanal fishery on Inhaca could be affected by the new restrictions. This was based on semi-structured interviews with local fishermen from Inhaca to learn about their fish habits such as caught fish species. The result showed that 21 % of the total amount of caught fish species stated by all fishermen from the interviews, was demersal species. Since demersal fishing will not be allowed within the new marine reserve, they have to fish differently to be able to fish legally. This report also contains a brief description of the current management system regarding fishery, which is based on interviews with managers/actors from different public sectors within the fishing industry.
    [Show full text]
  • Annual Meeting of the American Fisheries Society
    September 17, 2008 MEMORANDUM TO: H. Brent Clayton, Chief Environmental Technical Support Branch Division of Site and Environmental Reviews Office of New Reactors FROM: Harriet L. Nash, Aquatic Biologist /RA/ Environmental Technical Support Branch Division of Site and Environmental Reviews Office of New Reactors SUBJECT: FOREIGN TRIP REPORT: ANNUAL MEETING OF THE AMERICAN FISHERIES SOCIETY The enclosed trip report describes the August 17 - 22, 2008, 138th Annual Meeting of the American Fisheries Society, Ottawa, Canada in which I participated. The report is a combined quick look and final report. The content of this report is not likely to be of interest to the Commission. CONTACT: Harriet Nash, NRO/DSER/RENV (301) 415-4100 Enclosure: Foreign Trip Report w/Attachment: Meeting Agenda MEMORANDUM TO: H. Brent Clayton, Chief Environmental Technical Support Branch Division of Site and Environmental Reviews Office of New Reactors FROM: Harriet L. Nash, Aquatic Biologist Environmental Technical Support Branch Division of Site and Environmental Reviews Office of New Reactors SUBJECT: FOREIGN TRIP REPORT: ANNUAL MEETING OF THE AMERICAN FISHERIES SOCIETY The enclosed trip report describes the August 17 - 22, 2008, 138th Annual Meeting of the American Fisheries Society, Ottawa, Canada in which I participated. The report is a combined quick look and final report. The content of this report is not likely to be of interest to the Commission. CONTACT: Harriet Nash, NRO/DSER/RENV (301) 415-4100 Enclosure: Foreign Trip Report w/Attachment: Meeting Agenda Distribution: HNash [email protected] ADAMS ACCESSION NUMBER: ML082590548 OFFICE PM:DSER:RENV:NRO LA:DSER:RAP2:NRO NAME HNash ARedden DATE 09/17/08 09/16/08 OFFICAL RECORD COPY U.S.
    [Show full text]
  • Towards Sustainability in World Fisheries
    insight review articles Towards sustainability in world fisheries Daniel Pauly, Villy Christensen, Sylvie Guénette, Tony J. Pitcher, U. Rashid Sumaila, Carl J. Walters, R. Watson & Dirk Zeller Fisheries Centre, University of British Columbia, 2204 Main Mall, Vancouver, British Columbia, Canada V6T 1Z4 (e-mail: [email protected]) Fisheries have rarely been ‘sustainable’. Rather, fishing has induced serial depletions, long masked by improved technology, geographic expansion and exploitation of previously spurned species lower in the food web. With global catches declining since the late 1980s, continuation of present trends will lead to supply shortfall, for which aquaculture cannot be expected to compensate, and may well exacerbate. Reducing fishing capacity to appropriate levels will require strong reductions of subsidies. Zoning the oceans into unfished marine reserves and areas with limited levels of fishing effort would allow sustainable fisheries, based on resources embedded in functional, diverse ecosystems. ishing is the catching of aquatic wildlife, the aftermath of the Second World War added another ‘peace equivalent of hunting bison, deer and rabbits on dividend’ to the industrialization of fishing: freezer trawlers, land. Thus, it is not surprising that industrial- radar and acoustic fish finders. The fleets of the Northern scale fishing should generally not be sustainable: Hemisphere were ready to take on the world. industrial-scale hunting, on land, would not be, Fisheries science advanced over this time as well: the two Feither. What is surprising rather, is how entrenched the world wars had shown that strongly exploited fish popula- notion is that unspecified ‘environmental change’ caused, tions, such as those of the North Sea, would recover most, if and continues to cause, the collapse of exploited fish not all, of their previous abundance when released from populations.
    [Show full text]
  • American Fisheries Society • OCT 2013
    VOL 38 NO 10 FisheriesAmerican Fisheries Society • www.fisheries.org OCT 2013 Sound Science and Future Trends An Imperative Change is Needed Scary Habitat Numbers Avoiding Bycatch Digitizing Applications for Diversity Smartphones and Digital Tablets in Fisheries Fishery-Induced Collapse of Invasive Asian Carp 03632415(2013)38(10) Fisheries VOL 38 NO 10 OCTOBER 2013 Contents COLUMNS President’s Commentary 431 We Must Do Better—We Have To Do Better The major reason I am writing this column was that I learned from one of our members who is a person of color that I was the first person to really engage him in meaningful conversation at an AFS annual meeting. Until then, he felt that he had been invisible, if not disliked, for his race. Bob Hughes, AFS President Oregon commercial salmon fisherman Kevin Bastien trying Fish Habitat Connections 455 out the at-sea SPT system developed by Lavrakas et al. (2012). 432 Scary Numbers Photo credit: John Lavrakas. We know the challenges and must now seize the opportunities to protect and restore habitats. 455 Smartphones and Digital Tablets: Emerging Tools Thomas E. Bigford for Fisheries Professionals Our handheld digital devices and fisheries. Digital Revolution Lee F. G. Gutowsky, Jenilee Gobin, Nicholas J. Burnett, 433 Hiring Tools Jacqueline M. Chapman, Lauren J. Stoot, and Shireen Bliss Finding diversity in applications for fisheries programs can be an easier fix than you may think. BOOK REVIEWS Jeff Kopaska 462 Conservation, Ecology, and Management of Director’s Line Catfish: The Second International Symposium, edited 469 Sound Science and Future Trends by P.
    [Show full text]
  • COVID-19 Provides an Opportunity to Advance a Sustainable UK Fisheries Policy in a Post-Brexit Brave New World
    Marine Policy 120 (2020) 104114 Contents lists available at ScienceDirect Marine Policy journal homepage: http://www.elsevier.com/locate/marpol Short communication COVID-19 provides an opportunity to advance a sustainable UK fisheries policy in a post-Brexit brave new world Paul S. Kemp a,*, Rainer Froese b, Daniel Pauly c a International Centre for Ecohydraulics Research, Faculty of Engineering and the Physical Sciences, Southampton Boldrewood Innovation Campus, University of Southampton, SO16 7QF, UK b GEOMAR Helmholtz Centre for Ocean Research, 24105, Kiel, Germany c Institute for the Oceans and Fisheries, The University of British Columbia, 2202 Main Mall, Vancouver, B.C., V6T 1Z4, Canada ARTICLE INFO ABSTRACT Keywords: Brexit creates a systemic shock that provides a unique opportunity for the UK to implement a new sustainable Ocean harvest Fisheries Policy to better manage the multiple stocks on which future fisherswill depend on leaving the European European union fisheries policy Union. At the same time, the global slowdown of commercial fishing as a result of COVID-19 has reduced Marine fisheries management pressure on some threatened stocks to levels not seen since the Second World War. In combination, Brexit and the Water-energy-fisheries Nexus COVID-19 slowdown have created a unique opportunity to facilitate the recovery of a threatened resource. Nevertheless, challenges remain as fisheries represent only 0.12% of UK economic output, presenting a risk that opportunities for more sustainable management will be lost during wider
    [Show full text]
  • Unsustainable Marine Fisheries Daniel Pauly
    Sustainable Development Law & Policy Volume 7 Article 5 Issue 1 Fall 2006: Ocean & Fisheries Law Unsustainable Marine Fisheries Daniel Pauly Follow this and additional works at: http://digitalcommons.wcl.american.edu/sdlp Part of the Environmental Law Commons, International Law Commons, and the Law of the Sea Commons Recommended Citation Pauly, Daniel. “Unsustainable Marine Fisheries.” Sustainable Development Law & Policy, Fall 2006, 10-12, 79. This Article is brought to you for free and open access by the Washington College of Law Journals & Law Reviews at Digital Commons @ American University Washington College of Law. It has been accepted for inclusion in Sustainable Development Law & Policy by an authorized administrator of Digital Commons @ American University Washington College of Law. For more information, please contact [email protected]. UNSUSTAINABLE MARINE FISHERIES by Daniel Pauly* INTRODUCTION HISTORIC ANTECEDENT Many have long assumed that the expanse and mysterious While fisheries7 and localized overexploitation have depths of the world’s oceans contain vast living resources, ready occurred for millennia,8 the massive impact of fishing on ocean to be exploited in the ways that its more familiar coastal fringes ecosystems began only in the early nineteenth century, when have. This assumption is very wrong. Of the 362 million square English steam trawlers began to land their catches.9 These kilometers of ocean on this planet, only 7.5 percent — the conti- trawlers were soon rendered more effective by power winches nental shelves — are shallower than 200 meters (“m”), and some and, following World War I, diesel engines. The aftermath of of this shelf area is covered by ice.
    [Show full text]
  • Supplement A: Assumptions and Equations in Ecopath with Ecosim Governing Equations
    Transactions of the American Fisheries Society 145:136–162, 2016 © American Fisheries Society 2016 DOI: 10.1080/00028487.2015.1069211 Supplement A: Assumptions and Equations in Ecopath with Ecosim Governing Equations The Ecopath module of EwE is a static, mass-balance ecosystem model that uses two governing equations for each species and age group (Christensen and Walters 2004). The first governing equation describes each species group’s production for a time period, i.e., production (P) is the sum of fishery catch (F), predation (M2), net migration (immigration, I, and emigration, E), biomass accumulation (BA), and mortality from other sources (‘other mortality’, M0): P = F + M2 + (I - E) + BA - M0 The second governing equation is based on the principle of conservation of matter within a group, and is designed to balance the energy flows of a biomass pool, i.e., consumption (C) equals the sum of production (P), respiration (R), and unassimilated food (U): C = P + R + U At a minimum, Ecopath requires inputs of diet composition (DCi,j, where i is predator and j is prey), fishery catch (Yi), and three of the following four parameters for each model group (i): biomass (Bi), production-to-biomass ratio (Pi/Bi), consumption-to-biomass ratio (Qi/Bi), and the ecotrophic efficiency (EEi, the fraction of the production that is used in the system and does not move directly to the detritus pool). Mass-balance principles are then used to estimate the fourth parameter. P/B is the annual production rate of the population in Ecopath. Under equilibrium conditions, the P/B ratio of fish is equivalent to its total annual instantaneous mortality (Z) (Allen 1971).
    [Show full text]