1. Indicator

(a) Name: Population growth in coastal areas.
(b) Brief Definition:
(c) Unit of Measurement:

2. Placement in the Framework

(a) Agenda 21: Chapter 17: Protection of the Oceans, all Kinds of Seas, including Enclosed and Semi-enclosed Seas, and Coastal Areas; and the Protection, Rational Use and Development of their Living Resources.
(b) Type of Indicator: Driving Force.

(Indicator under development)

 

DISCHARGES OF OIL INTO COASTAL WATERS
Environmental	Chapter 17	Driving Force

1. Indicator

(a) Name: Discharges of oil into coastal waters.
(b) Brief Definition: Estimates of oil entering the coastal marine environment from land-based activities, maritime transportation, offshore exploration and exploitation, through the atmosphere, as well as natural seepages.
(c) Unit of Measurement: Metric tons.

2. Placement in the Framework

(a) Agenda 21: Chapter 17: Protection of the Oceans, all Kinds of Seas, including Enclosed and Semi-enclosed Seas, and Coastal Areas; and the Protection, Rational Use and Development of their Living Resources.
(b) Type of Indicator: Driving Force.

(Indicator under development)

RELEASES OF NITROGEN AND PHOSPHORUS TO COASTAL WATERS
Environmental	Chapter 17	Driving Force

1. Indicator

(a) Name: Releases of nitrogen and phosphorus to coastal waters.
(b) Brief Definition: Average annual load of nitrogen (N) and phosphorus (P) from land sources discharged into coastal waters.
(c) Unit of Measurement: Tons per year, reported separately for N and P, for a given watershed area, and when possible aggregated on a national basis.

2. Placement in the Framework

(a) Agenda 21: Chapter 17: Protection of the Oceans, all Kinds of Seas, including Enclosed and Semi-enclosed Seas, and Coastal Areas; and the Protection, Rational Use and Development of their Living Resources.
(b) Type of Indicator: Driving Force.

3. Significance (Policy Relevance)

(a) Purpose: This indicator represents the potential for impacts of nutrient releases into enclosed or semi-enclosed marine environments.

(b) Relevance to Sustainable/Unsustainable Development: This indicator reflects the negative externalities of fertilizer use, as well as domestic and industrial discharges of nitrogen and phosphorus. It is an indication of inadequate sanitation and/or wastewater treatment facilities, or pollution control. Nutrient enrichment of coastal waters may have consequences to important economic and environmental goods and services, for example, tourism and recreation, maintenance of the fishery potential, and decline or preservation of estuarine and marine biodiversity. The importance of normal to lightly enriched freshwater discharge, if free of associated chemical contaminants, to fisheries production, is however only now being fully recognized.

Such impacts are likely to be negative if uncontrolled, and if close to the point of discharge. For example, water quality deterioration, eutrophication (with consequent decreased light penetration and reduced dissolved oxygen levels), and degradation of fishery resources (especially demersal and benthic species). Low to moderate releases may enhance fishery production, given that natural levels of discharges from rivers sustain marine production at moderate to high levels in estuarine and coastal waters.

(c) Linkages to Other Indicators: The indicator is linked to many other socioeconomic, environmental, and institutional indicators including: use of fertilizers, land use and condition change, quality of freshwater resources, environmental protection expenditures, population growth in coastal areas, and participation in maritime agreements.

(d) Targets: Not available.

(e) International Conventions and Agreements: The following conventions and agreements apply to this indicator: Helsinki Commission on the Baltic, 1982, 1992; Black Sea Convention on the Environment, 1994; Sofia Convention (Danube), 1994; European Economic Community (EEC) directives on nutrients to water bodies; EEC Convention on Transboundary Pollution, 1983.

4. Methodological Description and Underlying Definitions

(a) Underlying Definitions and Concepts: Concepts are available. The indicator needs to be specific to a watershed and a receiving water body whose degree of mixing/water retention is important to determine effects. Further chemical specification of the nutrients is needed. While the contribution of same-size fluxes of ammonium-nitrogen and nitrate-nitrogen would be similar in regard to eutrophication (provided nitrogen is the limiting nutrient), their impacts to the receiving water body will be quite different.

(b) Measurement Methods: The methodology is not yet ready for immediate application in many areas. The indicator needs to be measured using the mass balance principle through a technique called Regional Mass Flux Budgeting. First, system boundaries need to be established using the watershed, or drainage basin, as its horizontal extension. Vertical boundaries in the atmosphere and ground need to be selected. Within those boundaries, the processes or activities relevant to the nutrient mass cycle (input-output) are determined. A time period of one year is usually selected for nutrient balances. Balances can be established only for total elements (total-N or total-P) or specific compounds. Additional information is needed to determine impacts.

(c) The Indicator in the DSR Framework: The indicator relates to marine pollution. It is a Driving Force indicator in the DSR Framework.

(d) Limitations of the Indicator: Effects will depend on assimilative capacity of water body (according to biophysical conditions). The indicator does not reflect the cumulative impact upon the water body. No indication is given as to the proportional contribution of different sources (including atmospheric deposition), or the prevalent paths of nutrients to coastal waters, unless broader information included in the preparation of the regional mass balance is available. In some cases, it is difficult to distinguish between anthropogenic nutrient loading and environmental conditions.

(e) Alternative Definitions: Releases of N and P by sources (agricultural, domestic, industrial) would indicate major contributions and guide policy action. Ratio of N/P releases would indicate which nutrient is the limiting factor for eutrophication. It would be appropriate for some countries which only border=1 on one sea, to select either N or P as the indicator, depending on which is of primary influence.

5. Assessment of the Availability of Data from International and National Sources

(a) Data Needed to Compile the Indicator: Regional mass balances for nitrogen and phosphorus.

(b) Data Availability: Very little data are available. Some input data on fertilizers and source-point measurements are available for specific areas.

(c) Data Sources: Principle data sources include: River and regional commissions and in Europe and North America; and studies on specific water bodies, for example the Mediterranean, Baltic, and Black Sea.

6. Agencies Involved in the Development of the Indicator

The lead agency is the United Nations Food and Agriculture Organization (FAO). The contact point is the Assistant Director-General, Sustainable Development Department, FAO; fax no. (39 6) 5225 3152.

7. Further Information

Baccini, P. and B.H. Brunner. Metabolism of the Anthroposphere (ISBN: 3-540-53778-3). 1991.

Isserman, K. Share of Agriculture in Nitrogen and Phosphorus into the Surface Waters of Western Europe against the Background of their Eutrophication. Fertilizer Research, 253-269, 1990.

 

MAXIMUM SUSTAINED YIELD FOR FISHERIES
Environmental	Chapter 17	State

1. Indicator

(a) Name: This indicator can be: (i) the ratio between maximum sustained yield (MSY) abundance and actual average abundance; or (ii) the deviation in stock of marine species from the MSY level.
(b) Brief Definition: This indicator is an expression of the state of fishery resource exploitation to its sustainable size.
(c) Unit of Measurement: %.

2. Placement in the Framework

(a) Agenda 21: Chapter 17: Protection of the Ocean, all Kinds of Seas, including Enclosed and Semi-enclosed Seas, and Coastal Areas; and the Protection, Rational Use and Development of their Living Resources.
(b) Type of Indicator: State.

3. Significance (Policy Relevance)

(a) Purpose: This indicator expresses the state of the fishery resource and/or its level of exploitation, in relation to either the MSY, or to virgin stock size. If spawning stock size is available, it has the further refinement of providing some indication of reproductive capacity of the resource.

(b) Relevance to Sustainable/Unsustainable Development: If a resource biomass is at or below that believed to apply under MSY conditions, or if the fishing effort or fishing mortality is at or above that believed to apply under the same conditions, there must be serious concern that the resource may currently be overexploited. This is not only because MSY conditions imply a level of fishing effort that is in excess of economically optimal harvesting, and has other biological impacts on target and associated species, but because the precision with which the underlying quantities used in these indices are measured is relatively low. Estimates of population biomass or cohort size, even in developed country fisheries, rarely are more precise than + or - 20%. Such a low precision presents a significant risk that fishing may be more intensive than is apparently measured by the indices, and that sustainable development options are possibly being compromised. Other more conservative and sophisticated indicators may be appropriate in particular circumstances (see United Nations Food and Agriculture Organization [FAO] reference in section 7 below).

(c) Linkages to Other Indicators: This indicator is closely linked to the other measures proposed for marine resources in Agenda 21. In a more general sense, it is also linked to socioeconomic indicators, such as population growth rate.

(d) Targets: The concept of using benchmarks and reference points as targets has been partly abandoned in recent fisheries conventions (see section 3e below). Given the great uncertainty with the stock size and condition of sea stocks, especially marine open stocks, two types of management bench marks are now proposed (See FAO reference in section 7 below). These are Target Reference Points (TRPs) focusing on the classical objectives of fisheries management; and Limit Reference Points (LRPs) which represent upper limits to the rate of fishing or fishing effort level (or lower limits to the population biomass or spawning biomass) that should not be passed. It is specified in the Conventions below that when LRPs are approached, action should be taken to ensure they are not exceeded.

With respect to national policy for exclusively national stocks, TRPs and LRPs should be estimated using the best scientific information available, and a precautionary approach applied where such information is inadequate. In the case of straddling, highly migratory, or transboundary stocks, such reference points and a joint exploitation strategy should be developed with other states sharing the same stock.

(e) International Conventions and Agreements: The Draft Agreement for the Implementation of the Provisions of the UN Convention on the Law of the Sea of 10 December 1982 relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks (Doc A/CONF 164/33), particularly Annex II, and of course the 1982 Convention itself, are of immediate relevance. The other significant draft agreement is the FAO Code of Conduct for Responsible Fisheries, which applies to all fisheries in marine and freshwater, and whose Article 6 also recommends the use of LRPs and TRPs.

4. Methodological Description and Underlying Definitions

(a) Underlying Definitions and Concepts: The measures used to provide the ratio indicators for MSY are well known, and described in a number of texts on fisheries assessment and population dynamics. The approach is based on the application of general production models.

It is felt that only one indicator based on Maximum Sustainable Yield is not the best way to measure the state of resource exploitation. Under these circumstances, a more empirical approach to developing indicators may be appropriate for a particular fishery; or a customized indicator may be developed from those given in the FAO reference listed in section 7 below which reflects the particular methodologies used for assessment of the resource in question. The MSY indicator is obtained by fitting the relationship between yield and fishing effort for a historical series of catch and effort data by a production model, but roughly equivalent indicators can be obtained from size or age based methods of analysis.

Fishing at the MSY level is now seen to be excessive, and determining MSY where it is not yet known, involves overfishing, which is obviously undesirable. Unfortunately, none of a number of alternative benchmarks for lower rates of fishing, such as described in the FAO report listed in section 7 below are widely accepted, so no obvious single alternative benchmark emerges. For many global fish stocks, MSY levels have not yet been determined.

Where MSY estimates are available, it should of course be possible to determine whether the fishing effort level corresponding to MSY (f[MSY]), or the corresponding fishing mortality rate (F[MSY]), is currently being exceeded or not. Depending on the fisheries management methodology used in a country, it may be possible, as an alternative, to say if the current biomass or spawning biomass of a particular stock has fallen below that corresponding to MSY (B[MSY]).

An alternative indicator that is commonly used to measure the state of the marine fisheries resources, and could be used instead of MSY-related indicators where these do not exist, is to specify what is the current biomass, or spawning biomass, as a percentage of the virgin biomass B[O], determined by surveys or other estimates of unexploited stock size, before the fishery had been established.

In summary, four alternative indicators are proposed:

(i) Ratio of current effort to that at MSY: (f[NOW]/f[MSY]);
(ii) Ratio of current fishing mortality rate to that at MSY: (F[NOW]/F[MSY]);
(iii) Ratio of current population biomass (or spawning biomass) to that at MSY: (B[MSY]/B[MSY]);
(iv) Current biomass to that under virgin conditions, that is, before fishing began: (B[NOW]/B[0]).

The above indicators are given as ratios, they are pure numbers, as are the instantaneous rates of fishing mortality. It is generally possible to cross-reference these indicators under specific assumptions, so that the apparent diversity of indices simply provides a choice that allows for the different information sources available under different fishery management regimes. In all cases, the indicator could be expressed in terms of the ratio and the component numerical values being divided.

(b) Measurement Methods: The measurement methods for each of the alternative indicators are described below:

i) f[NOW]/f[MSY]: The current effort level given in standard units adjusted for changes in fleet fishing power over time, is expressed as a ratio or percentage of the effort level under MSY conditions, where these prevailed and were estimated in the past.

ii) F[NOW]/F[MSY]: An instantaneous rate of fishing mortality F, is defined by the ratio of the natural logarithm of numbers for fully exploited cohorts now in the fishery at the beginning N(t), and end N(t+1) of the year, allowing for the instantaneous rate of mortality due to natural causes, M:F = [ln N(t) - ln N(t+1)] - M. This is calculated for the most recent year, [F(NOW)] and for the period when MSY conditions were believed to have applied, and the ratio taken.

iii) B[MSY]/B[MSY]: The biomass (or spawning biomass of mature animals) is determined for the most current year (for example, by trawl surveys) and compared with that level of biomass (or spawning biomass) when MSY conditions were believed to have applied.

iv) B[NOW]/B[0]: The biomass (or specific spawning biomass of mature animals) is determined for the most current year (for example, by trawl surveys) and compared with the level of biomass (or spawning biomass) before commercial exploitation began. Under a commonly-used population model, the logistic, MSY conditions occur when the stock size is reduced to 50% of the virgin stock size: that is, when this indicator shows values of 0.5 or lower.

MSY and biomass are usually specified in tonnes (1000 kg), and fishing effort either in standard number of days per year fished or total standard fleet horsepower (see Gulland reference in section 7 below).

(c) The Indicator in the DSR Framework: This indicator provides a measure of the State of the fisheries resource resulting from the pressure of human activities.

(d) Limitations of the Indicator: The major defect of the MSY concept, and of these indicators, is that MSY is determined by fitting an empirical "control curve" of catch on exploitation intensity or effort. This does not always fully reflect processes of birth and death, effects of exploitation on non-target species, or inter-species interactions, nor does it reflect changes in methodology of fishing. To improve management, it is important that countries collect ancillary data (for example, on size and age composition of catches and populations) that can be used to produce more refined indicators of value for the management of the resource, as their research funds and skilled manpower allow.

For many countries, suitable data to calculate these indicators are scarce. In addition, major deficiencies are characteristic of many available data sets. For example, there are serious deficiencies in data series for annual catch due to poor statistical design, lack of consideration of catches by small scale fleets, or problems where the extent and nature of unit resources have not been defined, or sharing taken into account. Not all national statistical offices collect the required data. In such cases, research institutes estimates are often developed from special research information collected and analysed by one or several qualified scientists.

(e) Alternative Definitions: See sections 4a and 4b above.

5. Assessment of the Availability of Data from International and National Sources

(a) Data Needed to Compile the Indicator: Data are required for annual catch, fishing effort, fishing mortality rates, biomass estimates, and stock size and age. Other supplementary data needs may be proposed, such as mean size or age in the catch (which goes down with fishing pressure); the percentage of mature fish in the catch, the overall instantaneous mortality rate, and the proportion of long-lived fish in the catch (for a multispecies fishery). These are of value to resource management, if they can be referred to the exploitation rate by human harvesting, specified as the target and limit conditions set as management reference points.

(b) Data Availability: Most countries collect data on annual catch. Not many countries maintain data on fishing effort by national fleets; still fewer standardize effort levels by different fleets and arrive at an annual total. Unless size and age compositions are collected and/or estimated from properly sampled catches in ports, fishing mortality rates will not be estimated, which in any case requires a cadre of trained fisheries scientists working in an equipped fisheries or marine science laboratory. Regular direct biomass estimates will require regular fisheries surveys using standard vessels and procedures with trained observers/fisheries biologists on board.

(c) Data Sources: National statistical offices often collect data on catches, and fleet size, but often require assistance in distinguishing species in the catch. At present, effort and mortality estimates, and other biological information used to develop the indicators mentioned above, are almost always performed by national marine resource institutes or universities.

6. Agencies Involved in the Development of the Indicator

(a) Lead Agency: The lead agency for the development of this indicator is the United Nations Food and Agriculture Organization (FAO). The contact point is the Assistant Director General, Sustainable Development Department, FAO; fax no. (39-6) 5225 3152.

(b) Other Organizations: The fisheries laboratories of the North Atlantic countries, particularly the UK, Canada and USA, and International Fisheries Commissions (notably the Inter-American Tropical Tuna Commission and the International Commission for Northwest Atlantic Fisheries (now defunct)) have sponsored the earliest applications of these indicators. The work of the International Center for living Aquatic resources Management (ICLARM), Manila has been aimed at applying these concepts in tropical fisheries.

7. Further Information

Food and Agriculture Organization. Reference Points for Fishery Management. FAO Fisheries Technical Paper 347. 1995.

Gulland, J.A. Fish Stock Assessment. Volume 1 FAO/Wiley Series on Food and Agriculture. 1983.

Hilborn, R. and C.J. Walters. Quantitative Fisheries Stock Assessment. Routledge, Chapman and Hall Inc. 1992.

Also see issues of the Canadian Journal of Fisheries and Aquatic Science over the last decade for articles outlining recent developments in this field.

ALGAE INDEX
Environmental	Chapter 17	State

1. Indicator

(a) Name: Algae index.

(b) Brief Definition: The Algae index could contain information of three elements: the type of algae (phytoplankton) species present, the composition of the algae species, and the amount of algae present in the water column.

(c) Unit of Measurement: Amount of algae per litre.

2. Placement in the Framework

(a) Agenda 21: Chapter 17: Protection of the Oceans, all Kinds of Seas, including Enclosed and Semi-enclosed Seas, and Coastal Areas; and the Protection, Rational Use and Development of their Living Resources.

(b) Type of Indicator: State.

(Indicator under development)