Acta Adriatica, Vol. 58 No. 1, 2017.
Izvorni znanstveni članak
https://doi.org/10.32582/aa.58.1.7
Decline of the Manila clams stock in the northern Adriatic lagoons: a survey on ecological and socio-economic aspects
Massimo PONTI
orcid.org/0000-0002-6521-1330
; Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA) & Centro Interdipartimentale di Ricerca per le Scienze Ambientali (CIRSA), University of Bologna, CoNISMa, Ravenna, Italy
Alessandra CASTELLINI
; Dipartimento di Scienze Agrarie, Università di Bologna. Viale Fanin, 50 - 40127 Bologna, Italy
Alessandro RAGAZZONI
; Dipartimento di Scienze Agrarie, Università di Bologna. Viale Fanin, 50 - 40127 Bologna, Italy
Elena GAMBA
; Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA) & Centro Interdipartimentale di Ricerca per le Scienze Ambientali (CIRSA), University of Bologna, CoNISMa, Ravenna, Italy
Victor Ugo CECCHERELLI
; Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA) & Centro Interdipartimentale di Ricerca per le Scienze Ambientali (CIRSA), University of Bologna, CoNISMa, Ravenna, Italy
Marco ABBIATI
; Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA) & Centro Interdipartimentale di Ricerca per le Scienze Ambientali (CIRSA), University of Bologna, CoNISMa, Ravenna, Italy
Sažetak
The Manila clam, Ruditapes philippinarum, introduced in the Venice lagoons in 1983 and rapidly spread to the nearby coastal lagoons represents one of the most important commercially-
exploited resources of this area. Abundance, size-class and biomass distribution of the wild population living in the Pialassa Baiona lagoon were assessed and related to the hydrological and sediment characteristics. Despite the lagoon being affected by eutrophication, chemical and thermal pollution, the clams were harvested by about thirty professional fishermen until 2003. The commercially available stock was estimated at 36.8 10^3 kg in July 2002, 29.3 10^3 kg in April 2003, and 10.3 10^3 kg in October 2003. Stock estimations and observed mortality were in good accordance
with the fishermen data. The decline of the available stock could be due to both overfishing and the extraordinary summer heat wave occurred in 2003, which may have reduced larval recruitment and
increased the mortality. Overall, the juvenile recruitment appeared insufficient to annually restore the natural stock. Although the national and regional high relevance of clams market, local harvesting of wild populations appeared marginal and inadequate to support a remunerative commercial activity, due to the variability and unpredictability of the annual yield and the lack of a sustainable management based on a production chain’s approach.
Ključne riječi
Clam fisheries; resources; harvesting; alien species; population dynamics; environmental conditions
Hrčak ID:
185177
URI
Datum izdavanja:
26.6.2017.
Posjeta: 946 *