Abstract
SUMMARY: The stalked barnacle Pollicipes pollicipes (Gmelin, 1790) is an important shellfish resource in Portugal. Due to the social-economic importance of barnacle harvesting, a management plan aimed at achieving a controlled and sustainable activity (including temporal and spatial closures, rotational harvesting, a limited number of harvesting licenses, bag and size limits for catches and catch reporting) was implemented in 2000 at the Berlengas Nature Reserve (RNB) in central Portugal. We evaluated the bag and size limits imposed by the management plan, performing observations on harvesting activity and asking licensed harvesters and RNB staff about these measures. Both inquiries and observations suggest that licensed harvesters are not following the bag and size limits imposed. Mean amounts captured in RNB varied from 14 to 24 kg per harvester/day, but 25% of the observations corresponded to higher catches per individual than the total amount allowed (20 kg). Only half of the sampled amounts (taken in autumn 2005 and 2006) were in agreement with the size limit regulation and 50% of the total biomass comprised individuals of maximal rostro-carinal length (RC) ≥25 mm. For most harvesters, size limit is the most difficult management rule to fulfil. Both harvesters and RNB staff agree that surveillance is scarce and is a major problem of this fishing activity. In order to achieve a more sustainable use of this resource, we propose the implementation of a more effective surveillance and monitoring plan, the definition of a unique landing site, the maintenance of the bag limit (20 kg) and a reduction of the size limit (50% of total biomass comprising individuals ≥22 mm RC).
Highlights
The stalked barnacle (Pollicipes pollicipes Gmelin, 1790) lives attached to rocks on very exposed shores (Borja et al, 2006a), forming dense aggregations of different-sized individuals in the intertidal and shallow subtidal zone along the northeast Atlantic coast from 48o to 14oN ( B a r n e s, 1 9 9 6 )
The number of boats observed per day varied between 0 and 10 (3.9±3.36, mean±SD, n=51), and the number of licensed harvesters observed per day varied between 0 and 42 (12.0±11.5, mean±SD, n=35)
Fig. 2. – Fishery of P. pollicipes in the Reserva Natural de Berlengas (RNB): frequency and cumulative frequency distribution of the average amount of barnacles (2 kg size classes) landed per harvester per day (n=287)
Summary
The stalked barnacle (Pollicipes pollicipes Gmelin, 1790) lives attached to rocks on very exposed shores (Borja et al, 2006a), forming dense aggregations of different-sized individuals in the intertidal and shallow subtidal zone along the northeast Atlantic coast from 48o to 14oN ( B a r n e s , 1 9 9 6 ). D e s p i t e it s c o m m e r c i a l in t e r e s t , p r o f e s sional barnacle harvesting along the Portuguese coast is not subject to specific regulations, except in the Berlengas Nature Reserve (since 2000) and in another protected area, the Natural Park of Sudoeste Alentejano and Costa Vicentina (since 2006). The Berlengas Nature Reserve (Reserva Natural das Berlengas, RNB) is situated approximately 6 miles off Cabo Carvoeiro (central Portugal, Fig. 1). It was created in 1981 due to its importance as an insular ecosystem, its high marine biological value, its botanical interest and importance to marine avifauna, and the presence of interesting archaeological features. From 1989 to 1998, barnacle harvesting was forbidden in the protected area, but barnacles were exploited and barnacle harvesting control was ineffective (Cruz, 2000)
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