Essential Fish Habitat in the Mediterranean and its implications for Ecosystem Based Approach to Fishery Management

Transcription

1 Essential Fish Habitat in the Mediterranean and its implications for Ecosystem Based Approach to Fishery Management Fabio Fiorentino Institute for Coastal Marine Environment (IAMC) Italian National Research Council (CNR)

2 It is well known that the spatial distribution of marine organisms is highly patchy over a large range of spatial and temporal scales but classical fishery management was based on control of impact of fisheries on dynamics of only two properties of exploited populations: - abundance (size of population), both in terms of yield or biomass at sea - demographical structure (length/age and sex composition) of catches or stock at sea and generally no information on stock occupancy of habitats over time was considered in the assessment and management framework

3 the increasing awareness of the ecological dimension of the fisheries forces to change from the classical objective to protect only the commercial stocks to the new one to protect also the environment and the communities in which the life cycles of commercial species occur this new approach implies the necessity to include space into fisheries sciences and improve spatial based approach to fisheries management by controlling catch in critical areas

4 the closures of areas to fisheries as an input control tools some legislative aspects The FAO Code of conduct (1995) stated that fisheries should promote protection of living aquatic resources and their environments and coastal areas The Ferguson Steven Fishery and Conservation Act (1996) introduced the protection of Essential Fish Habitat in USA fishery management The World Summit on Sustainable Development (2002) recommended to establish a network of MPA by 2012 The EC reg. 1967/2006 incorporated limits to towed gears on coastal areas and sensitive habitat, such as seagrass bed and mearl bottoms..

5 within this new ecological approach the protection of the Essential Fish Habitats becomes more and more relevant What is an Essential Fish Habitat Essential Fish Habitat (EFH) are bodies of water and substrate required for fish spawing, breeding, feeding, and a place they can grow to maturity. from Rosemberg et al. 2000

6 Knowledge of life cycles and ecology of the commercial species allows to identify critical period and habitat necessary to species to complete their different life stages. The classical sketch of stock dynamics in space Nursery Areas Spawning Areas Feeding Areas Technical measures could be proposed aimed to protect resource in critical period and areas linked to life history (for instance spawners and juveniles);

7 ..what is the role of closed areas in modern fishery management? Protect specific life stages; Rebuild depleted stock; Protect genetic reservoirs; Protect sensitive habitats (seagrass beds, maerl and coralligenous bottoms) From S.J. Hall (2009)

8 some examples to combine closed areas with closed season according to management objectives the case of a species having nurseries in costal bottoms where trawling is prohibited. Nursery closure Spawning areas closure from Caddy, 1999

9 the case of a species having nurseries in offshore bottoms where trawling is allowed.

10 What areas should be closed? Concerning the closures aimed to fishery target we have proposed a pragmatic approach, based on two steps, to select habitats to be protected 1) identify grounds where the abundance of critical phases in life cycle of commercial species (juveniles or spawners) are higher than the nearby areas; 2) measure persistence over time of use of these grounds by juveniles or spawners as the main prerequisite for any protection measures based on fishery closure..

11 Main nurseries of hake off the Italian coasts. Nurseries in the Adriatic Sea and the Strait of Sicily are located in international waters. From Murenu et al., 2010

12 Why we need to protect nurseries? Because the selectivity of Mediterranean trawlers is not enough to avoid catch of undersized specimens minimum legal size length at first maturity of males length at first maturity of females A typical length structure of hake catches in the Mediterranean trawlers with 40 mm diamond mesh

13 A typical length structure of Deep water rose shrimp in the Mediterranean trawlers with 40 mm diamond mesh Minimum legal size n of individuals coastal trawlers offshore trawlers CL (mm)

14 the selectivity of Mediterranean trawl net for hake Grey - Fiorentino et al., 1998 Black - Bethke 2004 (From Bethke, 2004)

15 the selectivity of Mediterranean trawl net for deep water rose shrimp % of c a pture d s hrim ps CL (mm) from Fiorentino et al., in prep

16 the nursery areas of deep water rose shrimp in the Strait if Sicily. Stable nursery (in red) and spawning areas location with the main hydrological characteristics of the north sector of the Strait of Sicily (from Fortibuoni et al., 2010).

17 Preliminaryanalysessuggestthatsmallertrawlers in the StraitofSicilyoperate on nurseriesofdeepwater rose shrimp. Distribution of 0+ rose shrimp Fishing effort pattern by VMS From Russo et al., 2012

18 A synoptic view of nurseries onf main groundfish in the Strait of Sicily From Garofalo et al., 2011

19 final considerations and suggestions for including the protection of the EFHs into the new FCP. 1) The Mediterranean fisheries is typically multi specific and multi gears 2) Mesh size at cod end of the towed nets is a compromise to catch several species of fish, crustaceans and cephalopods 3) The existing minimum mesh size is not reliable for fish that reach large size such as hake, anglerfish, sharks and skate 4) The adoption of new minimum mesh size larger than the 40mm square or 50mm diamond implies stopping catch of deep water shrimp, cephalopods and small size species of fish that is one of the main features of Mediterranean fisheries 5) An improvement of exploitation pattern of large size species, similar to an increase of mesh size, could be obtained adopting area and time closures targeted to postpone the size at first catch of species for which the current minimum mesh size is not adequate. 6) The technological progress of VMS allow to make reliable the enforcement of fishery closures in offshore waters