AMP Toolbox
1. Adaptive Management Case: ANCHOVY IN THE BAY OF BISCAY
WHAT DOES ADAPTIVE MANAGEMENT MEAN?
It is important for resource managers to acquire and use information and knowledge to promote sound management of natural resources, such as the European anchovy. Research and management may not be treated as separate activities, and should be integrated in a detailed framework.
Moreover, adaptive decision making involves the use of management itself to pursue management objectives and simultaneously learn about management consequences. A well designed plan provides the opportunity to learn about the decision process (i.e. institutional learning) and the resource system (technical learning).
THE CASE OF THE EUROPEAN ANCHOVY IN THE BAY OF BISCAY
The environmental resource: European anchovy (Engraulis encrasicolus) in the Bay of Biscay
The European anchovy is one of the most important pelagic species in the Bay of Biscay ecosystem. This short-lived (generally living less than three years) species spawns each year during spring in the Bay of Biscay, particularly on the Spanish and French coasts. Early juvenile stages start schooling as early as August and are found during summer and autumn in the southeastern part of the Bay of Biscay (Andonegi et al., 2011).
Figure 1: Engraulis encrasicolus.
Source.
Because it is a short-lived species, the state of the stock is determined largely by incoming recruitment. Recruitment is highly variable and depends on a variety of factors, such as the size of the spawning stock and the fishing pressure, but it particularly depends on the environmental and climatic conditions. In fact, annual fluctuations often seem random, and recruitment success often has a poor relationship to spawning biomass stock levels and fishing effort, making predictions difficult (Andonegi et al., 2011). Accordingly, although fisheries management frequently focuses on measures of the Spawning Stock Biomass, which is easily estimated; models are necessary to improve recruitment predictions and to manage fisheries effectively (Andonegi et al., 2011).
The eco-service: Fishing of anchovy in the Bay of Biscay
Anchovy has been one of the most important species for Spanish and French fleets operating in the Bay of Biscay. Both the economy of the fleets and the cultural roots of the surrounding countries have been largely conditioned by its availability (Andonegi et al., 2011). Basically, two types of fleets operate in the Bay of Biscay targeting anchovy:
1. The Spanish fleet comprises approximately 220 purse-seiners which operate mainly during spring in the SE area of the Bay of Biscay (ICES Divisions VIIIb and VIIIc).
2. The French fleet comprises about 30 purse-seiners and between 20-30 pelagic pair trawlers, depending on the abundance of stock. Pair trawlers operate in the VIIIb area during the first half of the year and in VIIIa during the second half.
Figure 2: Map illustrating the ICES Sub-areas VIII on the Western European coast.
Source.
Total landings of anchovy have fluctuated over time, peaking during the 1960s (~83 000 t) and at a minimum level in 2004 (< 10 000 t), just before the closure of the fishery in July 2005, because of the collapse of the stock. However, levels still remain weak (~6 000 t in 2010).
The problem: Need for a new adaptive management.
The anchovy in the Subarea VIII has been traditionally managed through annual Total Allowable Catch (TAC) fixed provisionally by the Council of Ministers in December; and then amended, once the Scientific, Technical and Economic Committee for Fisheries (STECF) has issued its advice the following June. This procedure is slow and may not allow the TAC to be set in time for the opening of a fishing season running from 1 July to 30 June the following year, as requested by the industry.
Moreover, since 2002 the total annual catches have been well below the fixed annual TAC. When a low recruitment occurs, a management regime based on fixed annual TAC which does not account for variability in recruitment, lacks any regulatory effect.
In addition, the dependency of the stock on recruitment is strongly linked to environmental conditions. In fact, successive recruitment failures since 2002 related to unfavourable environmental conditions, in combination with certain other factors such as fishing pressure, are believed to have been possible causes of the depletion of the stock (Andonegi et al., 2011).
Summarising, the fact that the management regime was based on a fixed annual TAC and the dependency of the recruitment on environmental conditions (as well as the lack of knowledge of these mechanisms), demonstrated that the management carried out was not adequate to deal with the occurrence of a stock collapse.
In order to manage anchovy populations and fisheries sustainably, an adaptive long-term management plan has been implemented.
Stakeholders
In order to decide the objectives as well as the different rules to manage the anchovy more effectively, different stakeholders are engaged, including the South Western Waters Regional Advisory Council (SWW RAC), managers and scientists. The SWW RAC includes:
- Two–thirds of its representatives come from the fishing sector (fishermen, ship-owners, organisations of producers, transformers, wholesale fish merchants and organisations of market) of five Members States (Portugal, Spain, France, Belgium and the Netherlands).
- One-third is composed of members’ organisations from civil society (aquaculture, consumers and environmental NGOs, wives of sailors, non-professional fishing...).
Objectives
Two main long-term objectives have been established:
(i) to secure relatively high yields from the exploitation of the anchovy stock, consistent with the Maximum Sustainable Yield (MSY); and
(ii) to guarantee the stability of the fishery as far as possible, while maintaining a low risk of stock collapse.
Main components of the new management plan
A new harvesting rule has been proposed which is calculated annually (instead of a fixed one) based on the monitored spawning biomass.
- if the mean measured spawning biomass ≤ 24 000 t fisheries closure
- if the mean measured spawning biomass is 24 001-33 000 t TAC=7 000t
- if the mean measured spawning biomass is > 33 000 t TAC= 30% of current biomass level up to a ceiling of 33 000 t.
In addition to the harvesting rule, some control provisions (i.e. special rules concerning fishing permits, vessel monitoring systems, effort and catch cross-checks) and financial assistance (if the fishery is closed or the biomass level falls below 33 000 t) are included in the new management plan.
This new rule permits a re-adjust of the Total Allowable Catch to anchovy availability annually. In addition, the plan allows for cyclical assessment and revision of the benchmarks, as well as the management alternatives and other elements of the designing.
Models
Although environmental and climatic conditions seem to be crucial for the anchovy´s recruitment levels, due to the lack of knowledge of the way these conditions affect recruitment and the difficulty in controlling environmental and climate variables, management of fishing effort becomes essential to avoid depletion of the stock. Hence, it will be necessary to bear this in mind during the assessment of this stock, avoiding, for instance, any increases in TAC based only on improvement in the observed status of the stock.
Accordingly, a coupled model is employed to predict the evolution of the anchovy stock in the short, medium and long term under several fishing-pressure scenarios and a given climate scenario. This coupled model consists on:
(i) a probabilistic recruitment model for anchovy, where the recruitment level is forecast based on a subset of climate or environmental indices;
(ii) a single-species anchovy model to analyse and forecast the anchovy population, based on the estimated recruitment levels.
In addition, the comparison between the predictions with the observed data, as well as the monitoring carried annually allows for knowledge accumulation to update and increase the confidence of the model.
Monitoring
The population is monitored by two annual spring surveys of the spawning stock: (i) the Daily Egg Production Method (DEPM); and (ii) the French acoustic (PELGAS: Campagne PELagiques GAScogne).
Due to the fact that the anchovy is a short-lived species, it is important to evaluate its biomass by direct assessment methods as the daily egg production method (DEPM). This method consists of estimating the Spawning Stock Biomass (SSB) as the ratio between: (i) the total daily egg production; and (ii) the daily fecundity estimates. In consequence, this method requires a survey to collect anchovy eggs (plankton sampling) for estimating the total daily egg production and to collect anchovy adults (adult sampling) for estimating the daily fecundity.
The biomass indices provided by the acoustic and DEPM surveys together with the information supplied by the fleet are used as input variables for a two-stage biomass dynamic model used to assess the Bay of Biscay anchovy population to assess the stock. In this model, the population dynamics are described for biomass with two distinct age groups, recruits or fish aged 1 and fish that are 2 or more years old (Ibaibarriaga et al., 2008).
Apart from the anchovy SSB estimates, the DEPM survey in the Bay of Biscay gives information on distribution and abundance of sardine eggs and on environmental conditions (e.g. sea surface temperature, sea surface salinity, temperature and salinity in the water column, currents and winds), which enables an increase in knowledge on the interactions between the environmental and climatic conditions and the species population.
Evaluation and adaptation based on the lessons learnt
The system allows for an in-year revision in order to tune-up catches for the second half of the year after the spring assessment. However, there is a lack of estimation of juveniles during the autumn which would allow forecasting of the abundance of fish during the first semester (winter-spring). In addition, there is a need to review and improve the models to manage the stock covering different scenarios.
Accordingly, an additional acoustic survey named JUVENA (juvenile anchovy acoustic survey) is being carried out to estimate juveniles during autumn. However, it is still under revision.
In addition, work is being done to achieve more accurate data to improve the models, especially data related to the prediction of real climate scenarios in the Bay of Biscay. This will be a key outcome to obtain sensible and reasonable predictions for the dynamics of anchovy stocks in the Bay of Biscay (Andonegi et al., 2011).
Apart for this technical learning, as mentioned above, the plan allows for cyclical assessment and revision of the benchmarks, as well as the management alternatives and other elements of the designing phase.
It is important for resource managers to acquire and use information and knowledge to promote sound management of natural resources, such as the European anchovy. Research and management may not be treated as separate activities, and should be integrated in a detailed framework.
Moreover, adaptive decision making involves the use of management itself to pursue management objectives and simultaneously learn about management consequences. A well designed plan provides the opportunity to learn about the decision process (i.e. institutional learning) and the resource system (technical learning).
THE CASE OF THE EUROPEAN ANCHOVY IN THE BAY OF BISCAY
The environmental resource: European anchovy (Engraulis encrasicolus) in the Bay of Biscay
The European anchovy is one of the most important pelagic species in the Bay of Biscay ecosystem. This short-lived (generally living less than three years) species spawns each year during spring in the Bay of Biscay, particularly on the Spanish and French coasts. Early juvenile stages start schooling as early as August and are found during summer and autumn in the southeastern part of the Bay of Biscay (Andonegi et al., 2011).
Figure 1: Engraulis encrasicolus.
Source.
Because it is a short-lived species, the state of the stock is determined largely by incoming recruitment. Recruitment is highly variable and depends on a variety of factors, such as the size of the spawning stock and the fishing pressure, but it particularly depends on the environmental and climatic conditions. In fact, annual fluctuations often seem random, and recruitment success often has a poor relationship to spawning biomass stock levels and fishing effort, making predictions difficult (Andonegi et al., 2011). Accordingly, although fisheries management frequently focuses on measures of the Spawning Stock Biomass, which is easily estimated; models are necessary to improve recruitment predictions and to manage fisheries effectively (Andonegi et al., 2011).
The eco-service: Fishing of anchovy in the Bay of Biscay
Anchovy has been one of the most important species for Spanish and French fleets operating in the Bay of Biscay. Both the economy of the fleets and the cultural roots of the surrounding countries have been largely conditioned by its availability (Andonegi et al., 2011). Basically, two types of fleets operate in the Bay of Biscay targeting anchovy:
1. The Spanish fleet comprises approximately 220 purse-seiners which operate mainly during spring in the SE area of the Bay of Biscay (ICES Divisions VIIIb and VIIIc).
2. The French fleet comprises about 30 purse-seiners and between 20-30 pelagic pair trawlers, depending on the abundance of stock. Pair trawlers operate in the VIIIb area during the first half of the year and in VIIIa during the second half.
Figure 2: Map illustrating the ICES Sub-areas VIII on the Western European coast.
Source.
Total landings of anchovy have fluctuated over time, peaking during the 1960s (~83 000 t) and at a minimum level in 2004 (< 10 000 t), just before the closure of the fishery in July 2005, because of the collapse of the stock. However, levels still remain weak (~6 000 t in 2010).
The problem: Need for a new adaptive management.
The anchovy in the Subarea VIII has been traditionally managed through annual Total Allowable Catch (TAC) fixed provisionally by the Council of Ministers in December; and then amended, once the Scientific, Technical and Economic Committee for Fisheries (STECF) has issued its advice the following June. This procedure is slow and may not allow the TAC to be set in time for the opening of a fishing season running from 1 July to 30 June the following year, as requested by the industry.
Moreover, since 2002 the total annual catches have been well below the fixed annual TAC. When a low recruitment occurs, a management regime based on fixed annual TAC which does not account for variability in recruitment, lacks any regulatory effect.
In addition, the dependency of the stock on recruitment is strongly linked to environmental conditions. In fact, successive recruitment failures since 2002 related to unfavourable environmental conditions, in combination with certain other factors such as fishing pressure, are believed to have been possible causes of the depletion of the stock (Andonegi et al., 2011).
Summarising, the fact that the management regime was based on a fixed annual TAC and the dependency of the recruitment on environmental conditions (as well as the lack of knowledge of these mechanisms), demonstrated that the management carried out was not adequate to deal with the occurrence of a stock collapse.
In order to manage anchovy populations and fisheries sustainably, an adaptive long-term management plan has been implemented.
Stakeholders
In order to decide the objectives as well as the different rules to manage the anchovy more effectively, different stakeholders are engaged, including the South Western Waters Regional Advisory Council (SWW RAC), managers and scientists. The SWW RAC includes:
- Two–thirds of its representatives come from the fishing sector (fishermen, ship-owners, organisations of producers, transformers, wholesale fish merchants and organisations of market) of five Members States (Portugal, Spain, France, Belgium and the Netherlands).
- One-third is composed of members’ organisations from civil society (aquaculture, consumers and environmental NGOs, wives of sailors, non-professional fishing...).
Objectives
Two main long-term objectives have been established:
(i) to secure relatively high yields from the exploitation of the anchovy stock, consistent with the Maximum Sustainable Yield (MSY); and
(ii) to guarantee the stability of the fishery as far as possible, while maintaining a low risk of stock collapse.
Main components of the new management plan
A new harvesting rule has been proposed which is calculated annually (instead of a fixed one) based on the monitored spawning biomass.
- if the mean measured spawning biomass ≤ 24 000 t fisheries closure
- if the mean measured spawning biomass is 24 001-33 000 t TAC=7 000t
- if the mean measured spawning biomass is > 33 000 t TAC= 30% of current biomass level up to a ceiling of 33 000 t.
In addition to the harvesting rule, some control provisions (i.e. special rules concerning fishing permits, vessel monitoring systems, effort and catch cross-checks) and financial assistance (if the fishery is closed or the biomass level falls below 33 000 t) are included in the new management plan.
This new rule permits a re-adjust of the Total Allowable Catch to anchovy availability annually. In addition, the plan allows for cyclical assessment and revision of the benchmarks, as well as the management alternatives and other elements of the designing.
Models
Although environmental and climatic conditions seem to be crucial for the anchovy´s recruitment levels, due to the lack of knowledge of the way these conditions affect recruitment and the difficulty in controlling environmental and climate variables, management of fishing effort becomes essential to avoid depletion of the stock. Hence, it will be necessary to bear this in mind during the assessment of this stock, avoiding, for instance, any increases in TAC based only on improvement in the observed status of the stock.
Accordingly, a coupled model is employed to predict the evolution of the anchovy stock in the short, medium and long term under several fishing-pressure scenarios and a given climate scenario. This coupled model consists on:
(i) a probabilistic recruitment model for anchovy, where the recruitment level is forecast based on a subset of climate or environmental indices;
(ii) a single-species anchovy model to analyse and forecast the anchovy population, based on the estimated recruitment levels.
In addition, the comparison between the predictions with the observed data, as well as the monitoring carried annually allows for knowledge accumulation to update and increase the confidence of the model.
Monitoring
The population is monitored by two annual spring surveys of the spawning stock: (i) the Daily Egg Production Method (DEPM); and (ii) the French acoustic (PELGAS: Campagne PELagiques GAScogne).
Due to the fact that the anchovy is a short-lived species, it is important to evaluate its biomass by direct assessment methods as the daily egg production method (DEPM). This method consists of estimating the Spawning Stock Biomass (SSB) as the ratio between: (i) the total daily egg production; and (ii) the daily fecundity estimates. In consequence, this method requires a survey to collect anchovy eggs (plankton sampling) for estimating the total daily egg production and to collect anchovy adults (adult sampling) for estimating the daily fecundity.
The biomass indices provided by the acoustic and DEPM surveys together with the information supplied by the fleet are used as input variables for a two-stage biomass dynamic model used to assess the Bay of Biscay anchovy population to assess the stock. In this model, the population dynamics are described for biomass with two distinct age groups, recruits or fish aged 1 and fish that are 2 or more years old (Ibaibarriaga et al., 2008).
Apart from the anchovy SSB estimates, the DEPM survey in the Bay of Biscay gives information on distribution and abundance of sardine eggs and on environmental conditions (e.g. sea surface temperature, sea surface salinity, temperature and salinity in the water column, currents and winds), which enables an increase in knowledge on the interactions between the environmental and climatic conditions and the species population.
Evaluation and adaptation based on the lessons learnt
The system allows for an in-year revision in order to tune-up catches for the second half of the year after the spring assessment. However, there is a lack of estimation of juveniles during the autumn which would allow forecasting of the abundance of fish during the first semester (winter-spring). In addition, there is a need to review and improve the models to manage the stock covering different scenarios.
Accordingly, an additional acoustic survey named JUVENA (juvenile anchovy acoustic survey) is being carried out to estimate juveniles during autumn. However, it is still under revision.
In addition, work is being done to achieve more accurate data to improve the models, especially data related to the prediction of real climate scenarios in the Bay of Biscay. This will be a key outcome to obtain sensible and reasonable predictions for the dynamics of anchovy stocks in the Bay of Biscay (Andonegi et al., 2011).
Apart for this technical learning, as mentioned above, the plan allows for cyclical assessment and revision of the benchmarks, as well as the management alternatives and other elements of the designing phase.