Ecopath can incorporate 150+ functional groups and 40+ fisheries Conservation Biomass ‘pools’ Tropic Level Trophic links

Mass balance: cutting the pie Other mortality Harvest Unassi- milated food Predation Harvest Respi- ration Respi- ration Predation Predation Other mortality Unassi- milated food Consumption Other mortality Unassi- milated food Predation Predation Respi- ration

INTRO 1 Ecopath An Introduction (1) 1.Mass-balance models Ecopath Defining the components of model Obtaining parameters of ecosystem functional groups Diet matrix Including fishery sectors and catches in the model Model construction Balancing the model Diagnosing the model Semi-Bayesian estimation (Ecoranger) Mass-balance ecosystem models (Ecopath 4). Components of model. Obtaining parameters of ecosystem functional groups. Diet matrix. Model construction. Balancing the model. Semi-Bayesian estimation (Ecoranger). Including fishery sectors and catches in the model. Simulations and “what if?” scenarios (Ecosim) Tropho-dynamic simulations using Ecosim. Split pools and recruitment. Limitations of the Ecosim technique – ecological interactions covered by Ecosim. Seasonal changes. Links between models. Spatial simulations of exploited ecosystems (Ecospace) Movement parameters of Ecopath groups. Substrate, production and habitat parameters. Modelling and design of marine protected areas using Ecospace. Reconstruction of past ecosystems: “Back to the Future”. Rebuilding and trade-offs to provide guidelines for ecosystem management. Incorporation of archival, archeological and TEK data on past ecosystems. Evaluation of benefits to society (Ecoval). Rapid appraisal of fisheries: (Rapfish) Multi-disciplinary, non-parametric, rapid appraisal of fisheries using ecological, technological, economic, social, ethical and ecosystem evaluation fields. Application to FAO Code of Conduct for Responsible Fisheries. Ordination method, mathematical basis, temporal trajectories, leverage analysis, Monte Carlo simulations and uncertainty, presentation of results. An Introduction (1)

Defining the ecosystem OPTIMAL CRITERIA Use natural ecological boundaries CONSTRAINTS Use reporting areas for fish catches ( landings ) Political boundaries may have to be used

Ecosystem: Odum’s definition “any entity or natural unit that includes living and nonliving parts interacting to produce a stable system in which the exchange of materials between the living and nonliving parts follows circular paths is an ecological system or ecosystem. The ecosystem is the largest functional unit in ecology, since it includes both organisms (biotic communities) and abiotic environment, each influencing the properties of the other and both necessary for maintenance of life as we have it on the earth. A lake is an example of an ecosystem.” Odum, E.P (1953) Fundamentals of Ecology B u t …. b e r e a l i s t i c …… !

INTRO 1 Ecopath An Introduction (1) 1.Mass-balance models Ecopath Defining the components of model Obtaining parameters of ecosystem functional groups Diet matrix Including fishery sectors and catches in the model Model construction Balancing the model Diagnosing the model Semi-Bayesian estimation (Ecoranger) Mass-balance ecosystem models (Ecopath 4). Components of model. Obtaining parameters of ecosystem functional groups. Diet matrix. Model construction. Balancing the model. Semi-Bayesian estimation (Ecoranger). Including fishery sectors and catches in the model. Simulations and “what if?” scenarios (Ecosim) Tropho-dynamic simulations using Ecosim. Split pools and recruitment. Limitations of the Ecosim technique – ecological interactions covered by Ecosim. Seasonal changes. Links between models. Spatial simulations of exploited ecosystems (Ecospace) Movement parameters of Ecopath groups. Substrate, production and habitat parameters. Modelling and design of marine protected areas using Ecospace. Reconstruction of past ecosystems: “Back to the Future”. Rebuilding and trade-offs to provide guidelines for ecosystem management. Incorporation of archival, archeological and TEK data on past ecosystems. Evaluation of benefits to society (Ecoval). Rapid appraisal of fisheries: (Rapfish) Multi-disciplinary, non-parametric, rapid appraisal of fisheries using ecological, technological, economic, social, ethical and ecosystem evaluation fields. Application to FAO Code of Conduct for Responsible Fisheries. Ordination method, mathematical basis, temporal trajectories, leverage analysis, Monte Carlo simulations and uncertainty, presentation of results. An Introduction (1)

B Mass-balance - Ecopath Biomass pools Production/Biomass — P/B Consumpt./Biomass — Q/B Ecotrophic efficiency Diet matrix Adjusted to mass- balance [Production of i] – [all predation on i] – [non predation losses of i] – [export of i] = 0 Christensen, V. and Pauly, D. (1992) The ECOPATH II - a software for balancing steady-state ecosystem models and calculating network characteristics. Ecological Modelling 61:169-185. Polovina, J.J. (1984) Model of a coral reef ecosystem. Part I: the ECOPATH model and its application to French Frigate Shoal. Coral Reefs 3: 1-11. Christensen, V. and Pauly, D. (1992) The ECOPATH II - a software for balancing steady-state ecosystem models and calculating network characteristics. Ecological Modelling 61:169-185. Polovina, J.J. (1984) Model of a coral reef ecosystem. Part I: the ECOPATH model and its application to French Frigate Shoal. Coral Reefs 3: 1-11.

Ecopath mass-balance equation How much is there of what eats them? is there? is used in system? important is it in their diet? more this year? gets caught? do they eat? Bi * (P/B)i * EEi = Yi +  Bj * (Q/B)j * DCji Production ( group i) Consumption (by group j)

Defining the ecosystem groups Functional ecological groupings Ecological similarities (niche overlap) rather than taxonomy to aggregate species Aggregate using cluster analysis on parameters Include groups needed for policy analysis (fisheries, conservation) Groups where data available Do not omit a known group for lack of data – its worse than using guesstimates Include all trophic levels Care with bacteria and microbial loop One (or more) must be a detritus group

Ecopath master equation 1 Production = biomass accumulation + predation + fishery + net migration + other mortality

Ecopath master equation Bi * P/Bi * EE i = Catch i +  Bj *(Q/B)j * DC ji + Export i Most common inputs: B, P/B, Q/B, Catch, diet (DC) so EE is estimated Balancing: DC’s modified to ensure EE’s are  1. How it is implemented

Estimations in Ecopath models For each group, your data in green, program estimates those in red. e.g. 1) B, P/B, Q/B, EE, DCs, ... 2) B, P/B, Q/B, EE, DCs, ... 3) B, P/B, Q/B, EE, DCs, ... 4) B, P/B, Q/B, EE, DCs, ... Ranked ease of estimation: P/B and Q/B > B > DCs >> EE hence EE often left unknown (Option 1 above)

Data requirements Key Data Requirements Biomass (t·km-2) Production / Biomass (ratio year-1) Consumption / Biomass (ratio year-1) Ecotrophic Efficiency (proportion) Diets (DC) (proportion) Catches (by fleet) (t·km-2 ·year-1) Economic data Ranges possible (Monte Carlo routines)

Open a model (File menu) Files are stored in Microsoft Access format Set up an .mdb file for each model ecosystem

Model information

Group information Click a group name

Double-click mouse to enter remarks Entering Remarks Double-click mouse to enter remarks Remarks possible - groups and output Cells with remarks are highlighted Use Ecowrite to extract remarks

Basic input

Basic parameterization (II) Basic input

Biomass Example from standard assessment methodologies don’t travel well, local information is important Time Biomass Example

A case for making 3 models Period 1 Period 2 Period 3 Time Biomass Example

INTRO 1 Ecopath An Introduction (1) 1.Mass-balance models Ecopath Defining the components of model Obtaining parameters of ecosystem functional groups Diet matrix Including fishery sectors and catches in the model Model construction Balancing the model Diagnosing the model Semi-Bayesian estimation (Ecoranger) Mass-balance ecosystem models (Ecopath 4). Components of model. Obtaining parameters of ecosystem functional groups. Diet matrix. Model construction. Balancing the model. Semi-Bayesian estimation (Ecoranger). Including fishery sectors and catches in the model. Simulations and “what if?” scenarios (Ecosim) Tropho-dynamic simulations using Ecosim. Split pools and recruitment. Limitations of the Ecosim technique – ecological interactions covered by Ecosim. Seasonal changes. Links between models. Spatial simulations of exploited ecosystems (Ecospace) Movement parameters of Ecopath groups. Substrate, production and habitat parameters. Modelling and design of marine protected areas using Ecospace. Reconstruction of past ecosystems: “Back to the Future”. Rebuilding and trade-offs to provide guidelines for ecosystem management. Incorporation of archival, archeological and TEK data on past ecosystems. Evaluation of benefits to society (Ecoval). Rapid appraisal of fisheries: (Rapfish) Multi-disciplinary, non-parametric, rapid appraisal of fisheries using ecological, technological, economic, social, ethical and ecosystem evaluation fields. Application to FAO Code of Conduct for Responsible Fisheries. Ordination method, mathematical basis, temporal trajectories, leverage analysis, Monte Carlo simulations and uncertainty, presentation of results. An Introduction (1)

Diet compositions Tuna Example Use volume or weight! Auxids 1.7% Partly digested fish 31.6% Others 19.3% Portunids 15.8% Euphausiids 3.5% Squids 12.3% Anchovies 8.8% Sardines 7% Auxids 1.7% Use volume or weight!

Estimation of diet compositions Diet compositions are often species-specific, and may need averaging. Use weighted averages; It is often necessary to modify the diet compositions to balance the model. ‘Import’ is feeding on prey groups that are not explicitly included in the ecosystem; Example: If marine mammals in a model of the near-surface open ocean feed on mesopelagics in the Deep Scattering Layer, then treat the mesopelagics as import

Diet composition entry

INTRO 1 Ecopath An Introduction (1) 1.Mass-balance models Ecopath Defining the components of model Obtaining parameters of ecosystem functional groups Diet matrix Including fishery sectors and catches in the model Model construction Balancing the model Diagnosing the model Semi-Bayesian estimation (Ecoranger) Mass-balance ecosystem models (Ecopath 4). Components of model. Obtaining parameters of ecosystem functional groups. Diet matrix. Model construction. Balancing the model. Semi-Bayesian estimation (Ecoranger). Including fishery sectors and catches in the model. Simulations and “what if?” scenarios (Ecosim) Tropho-dynamic simulations using Ecosim. Split pools and recruitment. Limitations of the Ecosim technique – ecological interactions covered by Ecosim. Seasonal changes. Links between models. Spatial simulations of exploited ecosystems (Ecospace) Movement parameters of Ecopath groups. Substrate, production and habitat parameters. Modelling and design of marine protected areas using Ecospace. Reconstruction of past ecosystems: “Back to the Future”. Rebuilding and trade-offs to provide guidelines for ecosystem management. Incorporation of archival, archeological and TEK data on past ecosystems. Evaluation of benefits to society (Ecoval). Rapid appraisal of fisheries: (Rapfish) Multi-disciplinary, non-parametric, rapid appraisal of fisheries using ecological, technological, economic, social, ethical and ecosystem evaluation fields. Application to FAO Code of Conduct for Responsible Fisheries. Ordination method, mathematical basis, temporal trajectories, leverage analysis, Monte Carlo simulations and uncertainty, presentation of results. An Introduction (1)

Fisheries data It is possible to include any number of fleets (or gears); Parameters for each variable costs fixed costs market prices landings discards fate of discards

Fishery: any number of fleets

Landings The landings (exclusive of discards) should be entered as rates (t · km-2 ·year-1) Landings with no cash value should be treated as landings (set price to 0), not as discards, which are fed back to the system

Entering landings, discards, prices

Market prices Non-market values Fleet-specific prices for each group that is harvested; Default value is 1 for all groups for all fleets. Non-market values ‘Existence’ values can be considered, e.g., the value for tourism of having, e.g., marine mammals in a system; Default value is 0.

Fleet-specific prices for all harvested groups Cost of fishing Fixed value of operating each gear can be entered (monetary currency per time unit) Variable cost is entered as relative to the effort in the Ecopath model Spatial fishing costs may be entered in Ecospace Any monetary currency can be used as unit Only simple bio- economic analyses are included Fleet-specific prices for all harvested groups

Discards are entered as rates t · km-2 ·year-1 Discard fate For fisheries with discards it is advisable to have a detritus group called, e.g., ‘dead fish’ Direct the fishery discards to this group Make scavengers feed on it NOTE: ‘Dead fish’ are of higher nutritional value than most other detritus (such as excreta from zooplankton) Discards are entered as rates t · km-2 ·year-1

Existence values ‘Existence’ values can be considered, e.g., the value for tourism of having marine mammals or large groupers in a system Default value is 0

ECOPATH 2 Ecopath An Introduction (2) 1.Mass-balance models Ecopath Defining the components of model Obtaining parameters of ecosystem functional groups Diet matrix Including fishery sectors and catches in the model Model construction Balancing the model Diagnosing the model Semi-Bayesian estimation (Ecoranger) Mass-balance ecosystem models (Ecopath 4). Components of model. Obtaining parameters of ecosystem functional groups. Diet matrix. Model construction. Balancing the model. Semi-Bayesian estimation (Ecoranger). Including fishery sectors and catches in the model. Simulations and “what if?” scenarios (Ecosim) Tropho-dynamic simulations using Ecosim. Split pools and recruitment. Limitations of the Ecosim technique – ecological interactions covered by Ecosim. Seasonal changes. Links between models. Spatial simulations of exploited ecosystems (Ecospace) Movement parameters of Ecopath groups. Substrate, production and habitat parameters. Modelling and design of marine protected areas using Ecospace. Reconstruction of past ecosystems: “Back to the Future”. Rebuilding and trade-offs to provide guidelines for ecosystem management. Incorporation of archival, archeological and TEK data on past ecosystems. Evaluation of benefits to society (Ecoval). Rapid appraisal of fisheries: (Rapfish) Multi-disciplinary, non-parametric, rapid appraisal of fisheries using ecological, technological, economic, social, ethical and ecosystem evaluation fields. Application to FAO Code of Conduct for Responsible Fisheries. Ordination method, mathematical basis, temporal trajectories, leverage analysis, Monte Carlo simulations and uncertainty, presentation of results. An Introduction (2)

Top predators are special They help constrain the parameter ranges for others

Life history shifts of diet Split top predator groups: adult and juvenile sub-groups capture diet shifts Later …… Ecosim simulations will be more realistic

This makes Ecospace simulations more realistic later Use of habitat area Example Biomass in lagoon 3 t / km2 Biomass elsewhere 0 t / km2 Lagoon area 1 km2 Total area 25 km2 Input Biomass : 3 t / km2 Habitat area : 0.04 i.e. 1/25 of total area This makes Ecospace simulations more realistic later

P/B - Production/Biomass = Z From catch composition data using standard stock assessment methodologies Natural mortality of fish from Pauly’s (1980) empirical equation: M = K0.65 · L∞-0.279 ·T0.463 F = catch / biomass P/B = Z = F + M P/B = K(L∞-Lavg)/(Lavg-L’) [B&H57]

Food consumption (Q/B) Growth (VBGF) Biomass (B) Q/B Wt = W·(1-e-K(t-t0))b t Food consumption (Q) Mortality t Nt = R·e-M(t-tr) K1 (Gross food conversion) t t t

Food consumption Welcome to Maxim’s Tilapia Lake Awasa, Ethiopia L = 23 cm, W = 265 g 12 16 20 24 04 Time (h) End of feeding Start of feeding

Q/B Food consumption - a tail story The faster swimming fish eats more

Q/B Food consumption - a tail story Yellow Aspect ratio, AR : Red AR = 9.8 AR = 1.3 Q/B = 3 · W-0.2 · T0.6 · AR0.5 · 3 eFt W = asymptotic weight T = temperature AR = aspect ratio Ft = foodtype (0 f. carn.)

Q/B Food consumption: a tail story When not to use it Only for symmetrical tails used for propulsion

P/C Production / Consumption gross food conversion efficiency Production and Consumption ratios are related for a given population If exploitation changes, the production (mortality) rate will change, and so will the consumption The P/C ratio is more conservative than either of the two rates individually

Niche: prey overlap

Niche overlap Each point shows overlap between a pair of groups

Niche overlap Each point shows overlap between a pair of groups Same predators different prey Each point shows overlap between a pair of groups

Niche overlap Same predators different prey Each of these two pairs has similar prey and predators Same prey different predators No overlap

Ecotrophic efficiency (EE) EE is the proportion of the production that is used in the system (for predation or export) 1-EE is ‘other mortality’ Best to let Ecopath estimate EE For most groups EE  <=1, exception, examples phytoplankton bloom EE  0.5 kelps EE’s  0.1 unexploited top predators EE  0 “Small pelagics don’t die of old age”.

Other input for Ecopath models For living groups Biomass accumulation rate Assimilation %* Diet compositions Net migration rate Detritus fate For fleets Landings Discards Discard fate Fixed cost of fishing Variable cost Market price by fleet and group Existence value Jobs *Default values : 20% for non-assimilated, 0 for others

Biomass accumulation (Bacc) Ecopath is not a steady-state model, biomasses can change over time Bacc is entered as rates ( t · km-2 ·year-1) Default 0, has been used in nearly all models Use Bacc if you have data showing change in biomass at start and end of the period to be modeled If B, P/B, Q/B and EE are entered for a group, the program will offer to estimate Bacc If Bacc values are non-zero, Ecosim will show change over time even without any change in fishing

Ecopath master equation 2 Consumption = production + unassimilated food + respiration

Non-assimilated food (U) Remember the Ecopath Master Equation (II): Q = P + R + U Q and P are estimated first Respiration (R) is then calculated as R = (Q - P) - U i.e.; changing U only impacts R The default value of 20% for U is generally acceptable, except for herbivores and detritivores where 40% leads to more reasonable R/B ratios.

Migration Immigration and Emigration are rates (t·km-2 ·year-1) Net migration enters into the production equation (Master Equation I) Migration is also used by Ecosim & Ecospace

Migration

Detritus fate At least one detritus group is required. It must be entered after the living groups on the Ecopath input form All living groups produce detritus, from excretion and egestion, and from ‘other mortality’ Possible Ecopath Groups POM DOM Discarded_fish It is therefore necessary to specify to which detritus group the detritus generated by a living group is directed

Detritus fate

Alternative input Per convention, respiration is calculated, not an input From the second Ecopath Master Equation respiration is calculated as Respiration = consumption - production - unassimilated food An alternative form for input is …. …… any of the terms in the second Master Equation, or some ratios based on these terms The standard input for Ecopath is then calculated

Alternative input

Key Ecopath routines Ecopath routines for entry of key data on the biology and exploitation of ecosystem groups, and for establishing mass-balance FishBase bridge (www.fishbase.org) established for input data Econet: network analysis for study of ecosystem form and functioning, incl. particle size distribution (PSD); Ecowrite routine for documentation of data and assumptions used when constructing and validating models. Incorporates reference database. Ecoempire module with empirical relationships

Ecopath includes extended help F1 key for help