Common, rare or extirpated? Shifting baselines for common angelshark, Squatina squatina (Elasmobranchii: Squatinidae), in the Northern Adriatic Sea (Mediterranean Sea)

Fortibuoni, Tomaso; Borme, Diego; Franceschini, Gianluca; Giovanardi, Otello; Raicevich, Saša

doi:10.1007/s10750-016-2671-4

Cited by 42 publications

(46 citation statements)

References 29 publications

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“…Due to local extinctions, S. squatina faced population fragmentation in most parts of its former geographic range encompassing European waters and the Mediterranean (Cavanagh & Gibson, 2007;Iglésias et al, 2010;Ferretti et al, 2015). The same pattern was documented in the Adriatic Sea, where the species is proposed to be extirpated from the northern part at least since the 1980s (Fortibuoni et al, 2016), but is considered present in the eastern central and south Adriatic Sea, with possible disjunctions in some northern localities (Jardas et al, 2008) (Fig. 1).…”

Section: Introductionsupporting

confidence: 69%

“…The fleet operated with specific nets ("squaenere" or "sklatare") and targeted angelsharks and other cartilaginous fish in the north of the basin. At the beginning of the twentieth century, considerable quantities of S. squatina were still landed in Venice and Trieste (Fortibuoni et al, 2016). However, during five basin-wide scientific trawl surveys carried out to assess benthic fish stocks between 1948 and 2005, the species was last recorded in 1958 (Ferretti et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…However, during five basin-wide scientific trawl surveys carried out to assess benthic fish stocks between 1948 and 2005, the species was last recorded in 1958 (Ferretti et al, 2013). Consequently, at present it is considered rare (Jardas et al, 2008;Fortibuoni et al, 2016), as is the case throughout the whole Mediterranean (Capapé et al, 2006;Kabasakal & Kabasakal, 2014;Ferretti et al, 2015). For instance, S. squatina is considered a severely declined species in Turkey (Frickle et al, 2007), and the species may now be absent from the waters of the Balearic Islands, where it used to be frequent (Ferretti et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea

Holcer

Lazar

2017

Nat. Croat.

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Two out of three critically endangered species of angelsharks (genus Squatina (Dumeril, 1806)) inhabiting the Mediterranean have been recorded in the Adriatic Sea, namely smoothback angelshark S. oculata Bonaparte, 1840 and common angelshark S. squatina (Linnaeus, 1758). While S. oculata has been extirpated from the Adriatic Sea due to overfishing, the presence of S. squatina remained questionable and some authors propose the species is regionally extinct since the 1980s. We present new data on the occurrence of S. squatina in the Croatian Adriatic Sea based upon inspection of collections from natural history museums and literature sources as well as three new records resulting from bycatch in commercial bottom trawls in 2016 and 2017. A low overall number of records and the complete absence of the species in scientific trawl surveys conducted since 1958, indicate its low abundance and question the effectiveness of scientific surveying in detecting rare species. Our analysis showed that this formerly abundant species is still present in the Adriatic Sea, emphasizing the importance of implementing novel approaches, such as citizen-science programmes, in studying its current distribution. Although the legal framework for angelshark conservation already exists, poor implementation and lack of any species-specific conservation measures will most probably result in further population declines and extinction of S. squatina from the Adriatic Sea. U Jadranu su zabilježene dvije od tri kritično ugrožene vrste sklatova koje žive u Sredozemnom moru (rod Squatina (Dumeril, 1806)), sklat žutan S. oculata Bonaparte, 1840 i sklat sivac S. squatina (Linnaeus, 1758). Dok je S. oculata nestala iz Jadrana zbog prevelikog izlova, prisutnost vrste S. squatina je upitna i neki autori predlažu da se vrsta proglasi regionalno izumrlom od 1980. godine. U radu donosimo nove podatke o pojavljivanju vrste S. squatina u hrvatskom dijelu Jadrana na temelju pregleda zbirki prirodoslovnih muzeja i literaturnih izvora te tri nova nalaza kao posljedice slučajnog ulova komercijalnim pridnenim koćaricama iz 2016 i 2017. Ukupni mali broj nalaza i potpuna odsutnost vrste u znanstvenim istraživanjima koćarenjem od 1958. ukazuju na njenu nisku brojnost i na upitni učinak znanstvenih istraživanja u pronalasku rijetkih vrsta. Naša analiza pokazuje da je ova nekad brojna vrsta još uvijek prisutna u Jadranu, uz naglasak na važnost primjene novih metoda za utvrđivanje njene trenutne rasprostranjenosti kao što su programi znanosti za građane. Iako pravni okvir za zaštitu sklata već postoji, njeno 314 Holcer, D. & Lazar, B.: New data on the occurrence of the critically endangered common angelshark... loše provođenje i nepostojanje bilo kakvih mjera zaštite specifičnih za tu vrstu vjerojatno će rezultirati daljnjim padom brojnosti populacije i izumiranjem sklata sivca u Jadranu.

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Section: Introductionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea

Holcer

Lazar

2017

Nat. Croat.

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“…For example, pelagic sharks declined by more than 95% during the last century (Ferretti et al, 2008), whilst demersal sharks, such as smooth-hounds (Mustelus spp. ), disappeared from most of the West Mediterranean in '70s and '80s (Massutí, 1971;Aldebert, 1997;Maynou et al, 2011;Ligas et al, 2013;Fortibuoni et al, 2016;Colloca et al, 2017).…”

Section: Impact Of Fishing On Commercial Stocks and By-catch Speciesmentioning

confidence: 99%

“…A growing body of knowledge and recent single species assessments are showing a general overexploitation status of commercial fish and shellfish stocks along with a rapid decline of large predators, such as sharks (Ferretti et al, 2008Fortibuoni et al, 2010Fortibuoni et al, , 2016. While the impact of poorly regulated fisheries is widely documented in EU Mediterranean waters (Colloca et al, 2013;Vasilakopoulos et al, 2014), the status of fisheries and stocks in non-EU countries, where a standardized fisheries data collection system is generally not yet fully enforced, is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Recent Trends and Impacts of Fisheries Exploitation on Mediterranean Stocks and Ecosystems

2017

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This review focuses on the recent data on Mediterranean fishing fleets and landings, results from stock assessments and ecosystem models to provide an overview of the multiple impacts of fishing exploitation in the different Mediterranean geographical sub-areas (GSAs). A fleet of about 73,000 vessels is widespread along the Mediterranean coasts. Artisanal activities are predominant in South Mediterranean and in the eastern basin, while trawling features GSAs in the western basin and the Adriatic Sea. The overall landings of fish, crustaceans and cephalopods, after peaking during mid 90s at about one million tons, declined at about 700,000 tons in 2013. However, while landings are declining in EU countries since the 90s, in non-EU countries a decreasing trend was observed only in the last 5-10 years. The current levels of fishing effort determine a general overexploitation status of commercial stocks with more than 90% of the stock assessed out of safe biological limits. Indicators obtained from available ecosystem models were used to assess the sustainability of the fisheries. They included primary production required to sustain fisheries (PPR), mean trophic level of the catch (mTLc), the loss in secondary production index (L index), and the probability of the ecosystem to be sustainably exploited (p sust ). In areas exploited more sustainably (e.g., Gulf of Gabes, Eastern Ionian, and Aegean Sea) fishing pressure was characterized by either low number of vessels per unit of shelf area or the large prevalence of artisanal/small scale fisheries. Conversely, GSAs in Western Mediterranean and Adriatic showed very low ecosystem sustainability of fisheries that can be easily related with the high fishing pressure and the large proportion of overfished stocks obtained from single species assessments. We showed that the current knowledge on Mediterranean fisheries and ecosystems describes a worrisome picture where the effect of poorly regulated fisheries, in combination with the ongoing climate forcing and the rapid expansion of nonindigenous species, are rapidly changing the structure and functioning of the ecosystem with unpredictable effects on the goods and services provided. Although this would call for urgent conservation actions, the management system implemented in the region appears too slow and probably inadequate to protect biodiversity and secure fisheries resources for the future generations.

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References

2022

The Baseline Concept in Biodiversity Conservation

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Common, rare or extirpated? Shifting baselines for common angelshark, Squatina squatina (Elasmobranchii: Squatinidae), in the Northern Adriatic Sea (Mediterranean Sea)

Cited by 42 publications

References 29 publications

New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea

New data on the occurrence of the critically endangered common angelshark, Squatina squatina, in the Croatian Adriatic Sea

Recent Trends and Impacts of Fisheries Exploitation on Mediterranean Stocks and Ecosystems

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