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La duplice valenza delle aree di ripopolamento attivo di Palinurus Elephas: utili siti di sperimentazione e potenti strumenti gestionali

Follesa, Maria Cristina (2012) La duplice valenza delle aree di ripopolamento attivo di Palinurus Elephas: utili siti di sperimentazione e potenti strumenti gestionali. [Doctoral Thesis]



Recent recognition of increased anthropogenic demands and influence on marine resources and ecosystem has led to a strong push for “active” marine conservation (Hockey e Branch, 1997; Lubchenco, 1997). The value of marine protected areas, particularly no‐take marine reserves, and the fundamental importance of understanding marine environments is now jointly recognized by politicians, conservation and management scientists and commercial fishermen. In this context are framed he remarkable results achieved by the establishment of restocking areas (no‐take areas), established in the seas surrounding Sardinia and aimed at improving the state of a resource of high commercial value such as the spiny lobster Palinurus elephas. Despite the fact that Sardinia, along the eastern part of Sicily, has always been one of the Italian regions with the highest productivity of lobster (data IREPA, 2007), in recent years the international community had become increasingly aware that the current management regulations were not longer sufficient to ensure a rational exploitation of the resource. The worrying picture of the state of the resource has therefore made necessary the search for innovative management policies, through the adoption of new management measures, that would lead to the increase of the stock. In this perspective the Ministry of Agriculture before and after the Autonomous Region of Sardinia, in collaboration with the University of Cagliari, have implemented several measures to protect the resource, including in 1998 the establishment of an area of restocking in the central‐western Sardinia. The restocking action of the reserve Pallosu, that now has lasted 14 years (1998‐2011), led to an increase in biomass of the species by 550% compared to 1997, the year before the establishment of the protection. Important results are also the effects recorded in the commercial areas of fishing surrounding the no‐take area in which, as a result of a continuous spillover of specimens (Follesa et al., 2007a,2011), an increase in productivity of the lobster up to a distance of about 6 km from the center of restocking has been highlighted, with the record of signs of this effect up to an area of about 20 km away. The validity of the research undertaken through the activation of restocking areas is actually witnessed not only by management results but also by the possibility of enhancing of knowledge of the lobster biology, that it proved to be useful in the management of the resource itself. For example, collecting a large amount of data during the breeding season has revealed that the size of the maximum reproductive potential, for Sardinian lobsters, is reached at 75‐85 mm LCS, well below the minimum capture imposed since 2006 by the same European Economic Community (LCS = 90 mm). This appeared a remarkably important result which confirmed the validity of the rules of governance currently imposed in the management of the lobster fishing. The minimum legal size (MTL), in our case, being well in excess of 15 mm compared to the size of the maximum reproductive potential (75 mm LCS), would enable females to have the opportunity to reproduce more than once before reaching the legal size. Protection of the youngest not only through an imposition of a minimum size of capture (MTL) but also of large specimens through the establishment of additional areas of protection and/ or re‐stocking and the introduction of controls on landing would be desirable for a more and better management of the resource. A careful enforcement of the management together with the support of the action exerted by the major areas of active recovery could undoubtedly improve the management of this important species of great commercial importance in the Mediterranean Sea. It is still to be emphasized that these results are important both from a management and scientific perspective, they would not have been achieved without the full cooperation of fishermen which believed in this experimentation. We hope that initiatives like the ones of the Autonomous Region of Sardinia that, in consequence of the positive results achieved in Su Pallosu, has activated in 2009 other 14 restocking areas, can be multiplied in many other Mediterranean areas. Given the positive result, it is thought that such experiments, together with the management rules currently in force, can contribute to better regulation of the resource in the entire basin.

Item Type:Doctoral Thesis
Date:29 March 2012
Tutor:Cau, Angelo
PhD classes:Ciclo 24 > Biologia e biochimica dell'uomo e dell'ambiente
Coordinator:Sanna, Emanuele
Institution:Universita' degli Studi di Cagliari
Divisions:Dipartimenti (fino a dicembre 2011) > Dipartimento di Biologia sperimentale
Subjects:Area 05 - Scienze biologiche > BIO/07 Ecologia
Uncontrolled Keywords:Palinurus Elephas, lobster, no take area, spillover, biomass, movement, growth, reproduction
ID Code:753
Deposited On:30 Mar 2012 12:38

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