Production or Biomass

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 -

Ecological studies have suggested that ecosystems evolve in a succession of stages of maturity (Odum 1969) so as to increase control system feedback, internalise flows and increase the specialisation and number of constituent components (Christensen 1992). It is believed that fisheries reduce the maturity of an ecosystem, by destroying its physical structure and shifting community composition to r-selected species. The ratio of total primary production to total biomass is a model-derived indicator thought to be a function of the “maturity” of the system (Christensen et al. 2000). This is because, in immature systems production exceeds respiration and this allows the system to evolve by accumulation biomass (and thus the ratio decreases as the system moves from an immature to a mature state). By tracking the value of this ratio through time or by comparing the value at fished and unfished sites, it may be possible to detect large-scale ecological effects of fishing (via changes in the value of the ratio).

Attribute

Ecosystem structure and function

Purpose

Fisheries

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: by itself P/B can be confounded by other maturity altering forces on the system and may not show only the effects of fishing. Further, 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. Thus, as one of a set of indicators it may be useful for characterising ecosystems and how they change.

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. 1992. Network analysis of trophic interaction in aquatic ecosystems.  55 p . ICLARM Contribution, 835ICLARM.

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.

Odum, E. P. 1969. The strategy of ecosystem development. Science 164, no. 18 April: pp 262-70.

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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Page created by:Shavawn Donoghue

Last modified on: Apr 10, 2014 16:44

Versions: 6, 5, 4, 3, 2, 1

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