The management of small pelagics

Comprise the 1/3 of the total world landingsComprise more than 50% of the total Mediterranean landings, whileTwo species, anchovy and sardine, are the main target species

The importance of small pelagics

Total Catches of clupeoids in the Mediterranean and Black Sea region

0

200000

400000

600000

800000

1000000

1200000

1950 1956 1962 1968 1974 1980 1986 1992 1998 2004

Year

To

tal

Cat

ch

es

(mt)

Medit_clupeidae

Europ_Med_Clupeidae

Total Catches of clupeoids in the Mediterranean and Black Sea region

0

200000

400000

600000

800000

1000000

1200000

1950 1956 1962 1968 1974 1980 1986 1992 1998 2004

Year

To

tal

Cat

ch

es

(mt)

Medit_clupeidae

Europ_Med_Clupeidae

The main fisheries of small pelagics in the Mediterranean are

Purse seinesTrawls (mainly pelagic trawls, prohibited in Greece)Nets

The importance of small pelagics

Small pelagics present a series of certain characteristics that are very important for the management of their resources

Present high abundancesExhibit extended horizontal and vertical movementsCharacterized by intermediate trophic levelAnchovy and sardine are characterized by short life span (the bulk of individuals

found at sea are up to 3y old)

As a result their stocks present high annual variability in abundance

and age composition based on successful year recruitment.Consequently their abundances are greatly affected by environmental

conditions

Comprise an important role in the energy flow of marine ecosystems, linking plankton to top predators (wasp-waist control) thus consisting “keystone” species in marine ecosystems

Consequently they are expected to be greatly affected by the climate changeAn effective management should be flexible depending on the fluctuations of the stocks

The importance of small pelagics

Upper TL (Bottom up Upper TL (Bottom up control)control)

Lower TL (Top down control)Lower TL (Top down control)

Upper TL (Bottom up Upper TL (Bottom up control)control)

Small pelagics

Lower TL (Top down control)Lower TL (Top down control)

Research areas/projects for an effective management of small pelagics

The previous described characteristics raise a series of questions regarding their assessment and the identification of the status of the different stocks

The most effective monitoring programs are based on:

1) Integrated assessment methods

The in year monitoring of the stock by fisheries’ independent methods (e.g. acoustics, DEPM).

The main drawback of these methods is the difficulty to adopt reference points for the stock

This difficulty could be overcome by integrated assessment methods (e.g. ICA, XSA)

data obtained by fisheries e.g. landings, ALK, Length frequency, selectivity

with the results from fisheries independent methods such as acoustics or DEPM

In order to define reference points, to obtain a more effective diagnosis of the in year status of the stocks

(e.g. SSB, abundance survey indices at age, recruit abundance, Z, E)

These methods are being applied in the Atlantic stocks and their adaptation for the Mediterranean stocks will significantly improve the management of small pelagics.

Integrated assessment methods

integratedintegrated

High dependence of small pelagics due to their short life span from the in year successful recruitment, which is strongly related to environmental conditions, making them vulnerable to climate changes

For an effective management, the identification of geographical areas that are important for the main life stages is crucial. These “critical habitats” for the small pelagics are:

nursery areas

spawning areas

adults habitats

The spatial dynamics of the different life stages (i.e. their variability in space and time) could imply the need for e.g. seasonal or temporal closures of certain geographical areas

Identify the variability of the spatial occupation of preferential sites across the years

2) Determination and mapping of the spatial dynamics of small pelagics life stages

The identification of these areas could be achieved by:

• integrating existing and new knowledge on the distribution and abundance of the species with

• satellite environmental data as well as• field data.

This allows modeling and mapping of these “critical” spawning, juvenile and adult habitats using advanced statistical analysis and GIS techniques

Regresion model : GAMs

+

Satellite data + distribution of species

SST in SST in ooCCSST in SST in ooCC

22o 23o 24o 25o 26o 27o

38o

39o

40o

41o

2004

22o 23o 24o 25o 26o 27o

38o

39o

40o

41o

22o 23o 24o 25o 26o 27o22o 23o 24o 25o 26o 27o

38o

39o

40o

41o

2004

mapping of the spatial dynamics

By integrating knowledge of fish spatial distribution (based on existing and new survey data) we can identify and use spatial indicators to capture the variability of the spatial occupation of preferential sites

across the years and:

• Setting reference points useful for management or

• Constructing diagnostic tables where departures from reference values may trigger alarm signals for the status of the stock in real time

mapping of the spatial dynamics

3) Ecosystem approach of small pelagics’ fisheries management through mass balance models

Consequently effective management of small pelagic fish requires ecosystem consideration.

Especially in the Mediterranean the multispecies nature of fisheries and the high species richness raise the need for the application and improvement of ecosystem approaches to fisheries management, with emphasis on the key – role of small pelagics

Small pelagic fish have a key role in pelagic ecosystems• They are very abundant and control the biomass of both the lower

(zooplankton) and upper (top predators) trophic levels (“wasp-waist”)• Their abundance and species composition is highly influenced by

environmental conditions• Fisheries may substantially reduce the biomass of small pelagic fish also

affecting the other trophic levels (e.g. top predators)

This could be visualized by building “Mass Balance Models”

Ecosystem approach of small pelagics’ fisheries management

The Ecosystem Approach could be very useful to:• Assess the ecological role (e.g. trophic flows) of small pelagic fish• Address different management scenarios and precautionary measures• Predict future changes in small pelagic fish abundance under specific conditions (e.g. environmental conditions, levels of fishing effort) as well as• Investigate the effect of the adaptation of certain management policies

Thank you for your attention!!