The management of small pelagics

Comprise the 1/3 of the total world landings Comprise more than 50% of the total Mediterranean landings, while Two 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 Year Total Catches (mt) Medit_clupeidae Europ_Med_Clupeidae Total Catches of clupeoids in the Mediterranean and Black Sea region Year Total Catches (mt) Medit_clupeidae Europ_Med_Clupeidae The main fisheries of small pelagics in the Mediterranean are  Purse seines  Trawls (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 abundances Exhibit extended horizontal and vertical movements Characterized by intermediate trophic level Anchovy 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 change An effective management should be flexible depending on the fluctuations of the stocks The importance of small pelagics Upper TL (Bottom up control) Lower TL (Top down control) Upper TL (Bottom up control) Small pelagics 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 integrated

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 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

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