Balanced harvest in the real world – Scientific, policy and operational issues in an ecosystem approach to fisheriesFAO, Rome, 20/09-2/10/2014

Balanced Harvest:Preliminary reflections on a possible

CBD normGarcia S.M., Charles A. and Rice, J.

IUCN-CEM-FEG

Two co-existing “norms”

1. «Stocks should be kept at biomass levels that can produce MSY» UNCLOS (1982) and – WSSD ( 2002) Declaration § 31 (a). The concept has been criticized by scientists since early 1970s but recognized in all summits.

2. «A key feature of the ecosystem approach includes conservation of ecosystem structure and functioning» CBD. 1998. Malawi principles for Ecosystem Approach: FAO adopted EAF in 2001.

3. Balanced Harvest distributes a moderate fishing mortality across the widest possible range of species, stocks, and sizes in an ecosystem, in proportion to their natural productivity, so that the relative size and species composition is maintained.

To what extent are these norms compatible? Could species-based rationality lead to ecosystemic rationality? Note that if all stocks in an ecosystem, including non-target stocks, were exploited (or rebuilt)

at MSY level, the result would correspond to “Balanced Harvest” at MSY level.

UNCLOS

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Reflections on the nature of the CBD «norm»

Both UNCLOS and the CBD are instruments of international law which establishes the consensual principles and goals of the global community.

However, it is often hard to effectively enforce international law and sanction non-compliance.

International law may become effective when reflected into national law, ultimate recognition.

The MSY norm with its requirement of the “best scientific evidence available” is a good example. It has been enshrine in the UNCLOS early drafts, used since the 1970s, in force since 1994 and embedded in many national legislation. Nonetheless, it has not been generally complied with, either at country, regional or global level and the problem has been stressed by both fishery scientists and ENGOs for decades.

By comparison, the 1992 CBD contained no specific article on marine and coastal biodiversity. These issues were integrated through the 1995 Jakarta Mandate on Conservation and Sustainable Use of Marine and Coastal Biological Diversity and the 1998 Malawi Principles of the Ecosystem Approach

Based on inputs from S. Beslier (IUCN-CEM-FEG), R. Warner

Reflections on the nature of the CBD «norm»

In the CBD, has decisional power only in the EEZs of its parties and only advisory function in the high seas. Moreover, the articles indicating the Convention objectives include the expression: as much as possible… and as appropriate, leaving a large margin of appreciation to States, reducing its strength.

Furthermore the Malawi principles are less binding than the CBD itself, being part of a subsidiary implementation document to the Jakarta Mandate and not part of the Convention itself. As such, the legal status of the Malawi Principles are closer to that of the General Principles of the FAO Code of Conduct than to the MSY, even though, in practice, the difference might be small.

If formally adopted by RSOs, the Malawi Principles and the related norms could become binding to their parties only and in most cases only in EEZs. Adopted by RFMOs, however, they could become opposable to their members but, thanks to the UNFSA, also to all States, acquiring broader status and applicability.

In any case, the non-binding CBD instruments have high moral power and in the practice of international law, are useful to indicate the level of agreement reached at a certain time in an international community, in a step-wise process of maturation of international wisdom.

So, based on such considerations, how would this norm be implemented?

Based on inputs from S. Beslier (IUCN-CEM-FEG), R. Warner

Possible normative frameworkLo

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Individual size or weight

Define: The norm boundaries: e.g. 0.05 to 2.0 m A baseline state (e.g. Bv, αv), either modelled (e.g. virgin)

or empirical (e.g. early exploitation) with slope and intercept and their variance

The minimum limit (BLim, αLim), to avoid reaching at all cost, based on risk assessment

The BH reference to aim at: maintaining the structure (slope) and deciding on the optimal level of pressure (intercept). Based on risk assessment

Limit

Boundaries?

BH Target

Baseline

Intercept? Slope? Variance?

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Possible normative frameworkDefine: The norm boundaries: e.g. 0.05 to 2.0 m A baseline state (e.g. Bv, αv), either modelled (e.g. virgin)

or empirical (e.g. early exploitation) with slope and intercept and their variance

The minimum limit (BLim, αLim), to avoid reaching at all cost, based on risk assessment

The BH reference to aim at: maintaining the structure (slope) and deciding on the optimal level of pressure (intercept). Based on risk assessment

Present state: B<0.5Bv, α>αv

Decision:Reduce pressure on large species and individuals

Caveat: Foresee impact of feedback loop on their preys and adaptive approach

Present state

How to translate this normative frame into measures (restrictions or incentives) for specific fishery systems?

Log

(Num

bers

, Bio

mas

s; p

rodu

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Individual size or weight

Possible monitoring systemX/Xref

0 1.0

α/αref

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0.2

Bioecologically non-viable

Overfishing small sizes or

Underfishing large ones

(unlikely development)

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Relative slope = chenge in balance)

Virgin

BH zone

0.5 BMSY~_

Conventional Trajectory

BH Target zone

BH-driven trajectory

Scientific questions on the norm

Versatility: In benthic, pelagic, coastal, high seas, polar, temperate and tropical ecosystems? Data poor systems?

Relevance of species versus size categories: How to combine species and sizes dimensions of BH?

Nesting: How to complement tactical stock assessment with strategic ecosystemic assessment? Nested assessment and governance scales.

Response time: Considering the frequencies of oscillations in a given ecosystem what are the detection and response time necessary to avoid chaotic developments?

Ambiguity: If the norm appears violated (e.g. slope too high) should we reduce pressure on large individuals or increase it on small ones? Or both? Impact? Costs? Equity?

Boundaries: what are the consequences on the norm of excluding certain species/sizes from the norm? Large mammals? Birds? Eggs and larvae?

Assessment: foresee ecological as well as socioeconomic and operational impacts

Low-cost application: can the norm be applied partially? Progressively? Excluding species/fisheries. Can catch composition be a proxy for biomass composition?

Scientific questions on the norm (2)

Diversity: Position of planktophagous or pupping sharks in the trophic model? How much variability is there in the size /productivity relation?

Comprehensiveness: How do plankton and benthos as well as mammals, crustaceans and mollusks fit in length-based and mass-balance models?

Models realism: How much can we “trust” e.g. mass-balance models which assume that each species belongs to one trophic level only? On size-based models assuming that one «spcies» process can represent processes within the entire trophic system.

Some overarching questions are: Can we model assemblages and ecosystems accurately enough to make credible

predictions? Can ecosystems be manipulated with the help of science?

The same problem exists with conventional fishery science (with its Cartesian approach) but it is rarely raised at system level.

Some practical questions

What boundaries of the management unit: Subsector; Sector/EEZ; LME? What time scale: Tactical (e.g. yearly) vs strategic (e.g. every 5-10 years) framework? Information needed and assessment protocol? Data-poor situations? What implications for industry: technological adaptation. Costs. Ability. Agility What synergetic measures: fishing rights? Discard bans? MPAs What enforcement strategy: at systemic and fisheries levels (nesting). At sea? On land?

Penalties types and level? How to assess performance: periodicity, cost?

These and many other questions will be addressed in another presentation on management implications of BH

Balanced harvest in the real world – Scientific, policy and operational issues in an ecosystem approach to fisheriesFAO, Rome, 20/09-2/10/2014

Balanced Harvest: Preliminary reflections on a possible CBD normGarcia S.M. , Charles A. and Rice, J.

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