Human impacts on the endangered fan mussel,Pinna nobilis

Abstract

Pinna nobilis is a sensitive and vulnerable species and is hence considered a good indicator of anthropogenic pressures on marine ecosystems. This study provides novel data on the density and distribution of endangered P. nobilis on the Turkish coasts. Threats to the status of P. nobilis, including by‐catch and illegal collection, were assessed, as was the general awareness of people about the endangered status of fan mussels. The data sources consisted of direct observations from diving surveys and the local ecological knowledge (LEK) of fishers and scuba‐divers. Results demonstrated that the density of P. nobilis significantly changed with environmental parameters, such as depth, and among different sampling areas. The number of damaged individuals was lowest in the areas that were distant from human influences such as ports and tourist beaches. The density estimations of P. nobilis across a wide geographic area around the Turkish coasts revealed that the density of fan mussels was highest around western coasts in comparison with southern coasts. Fishers and divers indicated that the population of this species has decreased during the last decade. The main causes of this decline were suggested to be the impacts of fishing gear, poaching, pollution, and boat anchoring. The highest volume of by‐catch was estimated to be taken by trawls. In general, the knowledge and local awareness of the conservation importance and status of fan mussels was poor. The study has identified those areas where fan mussels occur at a high density, and hence may indicate areas for possible conservation protection status. Second, areas exposed to the illegal harvesting of fan mussels were highlighted. Societal concern would benefit from educational activities to raise awareness of the ecological importance and conservation needs for fan mussels in Turkey.

Mass mortality of the fan mussel, Pinna nobilis in Turkey (eastern Mediterranean)

“…Based on Öndes et al. (2020), data were collected between June and September 2019 from 12 locations in the Aegean Sea and from 1 site in the Sea of Marmara, around Kapıdağ Peninsula (Figure 1), where only a small population was reported to have existed. In order to determine the fan mussel density, divers surveyed 10 randomly selected replicate plots each with an area of 25 m 2 (5 m × 5 m) at depths between 0 and 10 m from each location.…”

“…The species is known as the largest bivalve for this region (Katsanevakis, 2006). Pinna nobilis lives at depths ranging from 0.5 to 80 m (Öndes, Kaiser, & Güçlüsoy, 2020). The habitats of P. nobilis include algae and phanerogam facies, muddy and sandy substrates (Katsanevakis, 2006; Prado, Caiola, & Ibáñez, 2014).…”

“…Although P. nobilis has been protected, based on the European Council Directive 92/43/EEC (EEC, 1992) and the Barcelona Convention (Cabanellas‐Reboredo et al., 2019), its population abundance has declined and its habitats have degraded over the last few decades due to human impact including development of coastal areas, illegal collection, fishing activities and pollution (Basso et al., 2015; Öndes et al., 2020). It was reported that areas which are least affected by human activities represented a higher density of specimens with lower rates of damage, in comparison with ports and touristic beaches (Öndes et al., 2020).…”

“…In Turkey, Acarlı, Lök, and Acarli (2011) investigated the spat settlement of this species, and Öndes et al. (2020) discussed the human impact on this species using information on population density in 2017 before the MME. The present study provides information on the MME and mortality rates of P. nobilis population in Turkey in 2019, and its latest density status from Turkish waters.…”

Effects of pollution on marine organisms

“…Using observations from diving surveys and the local ecological knowledge (LEK) of fishers and scuba-divers, Ondes, Kaiser, and Guclusoy (2020) report that illegal trawl fishing in shallow waters may be a large component of fan mussel bycatch affecting the density and distribution of the endangered fan mussel, Pinna nobilis, on Turkish coasts.…”