Throughput

Indicator summary

Summary of indicator structure and function

Examples of how the indicators is used for ecosystem management and ecosystem status and trends

Definition and/or background

The following is from Fulton et al 2004a -

This is a model-derived measure, which represents the sum of all flows into and out of the components (species or groups) in the system. It includes all imports and exports of useable materials and energy (including catch, migration and the like), respiration and flows to and from any detrital components of the ecosystem. On a per area basis, it is a better indicator of system size than biomass (Ulanowicz 1986) and is useful for the comparison of flow networks (i.e. system at different times of fished vs unfished systems) (Christensen et al. 2000). The basis for this usefulness is that over the last twenty years ecologists (e.g. Ulanowicz 1986) have developed an interpretation of ecosystem structure and function that is based on thermodynamics and information theory. Under this scheme system growth is characterised by flows not total biomass and thus throughput is a better measure of the system size, with throughput increasing as the system grows (Christensen 1994). Unfortunately, calculation of throughput will not be possible for all systems due to its data requirements (ICES 2001A).

Attribute

Ecosystem structure and function

Purpose

Ecosystem size

Taxa

As appropriate list an taxa that this indicator is restricted to

Data required

The following is from Fulton et al 2004a -

• Biomass per species (or group) recorded (preferably at least for the main components of the ecosystem and through time or vs. some reference area)
• Taxonomic data (or at least categorisation of the main components of the system)
• Catch data of species in fishery
• Mortality estimates for each group
• Consumption / Biomass estimates for each group
• Diet data

Ecosystem applicability

The following is from Fulton et al 2004a -

Should be applicable in all ecosystems.

Identified capability

Is there any additional information that would be of interest in regards to the identified capability?

Otherwise can leave this section blank and just fill in the table instead.

Biological classification level

Is there any additional information that would be of interest in regards to the biological classification level?

Otherwise can leave this section blank and just fill in the table instead.

Response variable

Is there any additional information that would be of interest in regards to the response variable?

Otherwise can leave this section blank and just fill in the table instead.

Drivers

Is there any additional information that would be of interest in regards to the identified capability?

Otherwise can leave this section blank and just fill in the table instead.

Robustness

The following is from Fulton et al 2004a -

Medium to low: determination of the throughput of the system is data intensive, and by itself probably not very informative. However, if it can be estimated, and as part of an integrated set of indicators (e.g. in conjunction with an empirical indicator or other model based indicators such as Relative Ascendency, which is a measure of system development), it could be very useful for characterising the system and how it has changed. As a model-derived indicator it is reliant on the assumptions used to construct the underlying model and the data used to parameterise and initialise the model. This makes it unsuitable as a predictive indicator, but this does not prevent it from being an informative indicator, especially if it is part of a larger suite of indicators.

Current status and trends

What was it like in an undisturbed/unexploited system?

How would it be expected to change?

Which way is the indicator showing a population is going in? decreasing or increasing?

Management objective/direction

Using the standard set of management objectives from Indiseas
* Conservations biodiversity
* Ecosystem stability and resistance to perturbations
* Ecosystem structure and functioning
* Resource potential

Has it been used in a management strategy? if so how?

List any relationships with management strategies/objectives

Stakeholder/Public acceptability

Acceptability with stakeholders?
* by all stakeholder
* by the public
* understandable to the stakeholders

References

Fulton, E.A., Smith, A.D.M., Webb, H., and Slater, J. (2004a) Ecological indicators for the impacts of fishing on non-target species, communities and ecosystems: Review of potential indicators. AFMA Final Research Report, report Number R99/1546.

References that Fulton et al uses for this indicator:

Christensen, V. 1994. On the behaviour of some goal functions for ecosystem development. Ecological Modelling 75/76: pp 37-49.

Christensen, V., C.J. Walters, and D. Pauly. 2000. ECTOPATH with ECOSIM: a user’s guide. October 2000 edition. Fisheries Centre, University of British Columbia, Vanouver, Canada and International Centre for Living Aquatic Resources Management, Penang, Malaysia.

ICES. 2001a. Report of the Working Group on Ecosystem Effects of Fishing Activities. International Council for the Exploration of the Seas, CM 2001/ACME: 09, 102pp.

Ulanowicz, R.E. 1986. Growth and development: ecosystem phenomenology. Springer-Verlag, New York, 203pp.

Background reading

Fulton, E.A., Fuller,M., Smith, A.D.M., and Punt, A. (2004) Ecological indicators of the ecosystem effects of fishing: Final report. AFMA Final Research Report, report Number R99/1546.

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Citation

Page created by:Shavawn Donoghue

Last modified on: Apr 10, 2014 16:57

Versions: 5, 4, 3, 2, 1

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