The Mediterranean Sea is classified as a “data-poor” region in fisheries due to its low number of assessed stocks given its biodiversity and number of exploited species. In this study, the CMSY ...method was applied to assess the status and exploitation levels of 54 commercial fish and invertebrate stocks belonging to 34 species fished by Turkish fleets in the Eastern Mediterranean (Levantine) and Black Seas, by using catch data and resilience indices. Most of these marine taxa currently lack formal stock assessments. The CMSY method uses a surplus production model (SPM), based on official catch statistics and an abundance index derived from scientific surveys. The SPM estimates maximum sustainable yield (MSY), fishing mortality (F), biomass (B), fishing mortality to achieve sustainable catches (Fmsy), and the biomass to support sustainable catches (Bmsy). Our results show the estimated biomass values for 94% of the stocks were lower than the required amount to support sustainable fisheries (Bmsy). Of the 54 stocks, 85% of them can be deemed as overfished; two stocks were not subject to overfishing (Sardina pilchardus and Trachurus mediterraneus in the Marmara Sea) while only one stock (Sprattus sprattus in the Black Sea) is healthy and capable of producing MSY. Annual values of the stock status indicators, F/Fmsy and B/Bmsy, had opposing trends in all regions, suggesting higher stock biomasses could only be achieved if fishing mortality is drastically reduced. Recovery times and levels were then explored under four varying F/Fmsy scenarios. Under the best-case scenario (i.e., F = 0.5Fmsy), over 60% of the stocks could be rebuilt by 2032. By contrast, if normal fishing practices continue as usual, all stocks will soon be depleted if not already (F = 0.95Fmsy), whose recover may be impossible at later dates. The results of this study are supported by previous regional assessments confirming the overexploitation of Turkish fisheries is driving the near-total collapse of these marine wild fisheries. Hence, the need to urgently rebuild Turkey’s marine fisheries ought to be prioritized to ensure their future viability.
A timeline of commercial fisheries extinctions and a list of threatened or extirpated marine species are presented to document the rapidly declining abundance of marine resources in the Turkish part ...of the Black Sea and Marmara Sea. Turkish nationally reported fisheries data were compared over a 50-year period from 1967 (the first year data were spatially allocated) to 2016 to assess which species are now extirpated (i.e., earlier present, and now absent from reported catch data), and which species have become commercially extinct (i.e., whose catch declined by 80.0 - 99.9%). The size of bony fish caught in Turkish waters has also strongly declined. Other important taxa, specifically big sharks and mammals, not covered by fisheries statistics, or currently under protection, but also exhibiting worrisome declining trends, are discussed based on accounts based on peer-reviewed and grey literature and personal accounts from local scientists and fishers. Overall, the Turkish parts of the Black Sea lost 17 extirpated species and 17 commercially extinct marine species, while the Sea of Marmara lost 19 extirpated species and 22 commercially extinct species. This study commemorates the many lost species of the Black and Marmara Seas, and may be seen as a warning call to prevent dozens of others species to be lost. We urge the Turkish authorities to take measures to effectively reduce fishing effort and thus to allow for a natural rebuilding of what remains of the fish stocks exploited by commercial fisheries.
The Eastern Mediterranean Sea is the most invaded sea on the planet, with 666 non-indigenous species now recorded in the region. However, not all of these become successful in their new environments. ...Success here is defined by wide geographical spread, increased abundances, and larger maximum sizes than their native range. The silver-cheeked toadfish Lagocephalus sceleratus (Gmelin 1789) was first recorded in the Mediterranean Sea in 2003. It has now spread to all corners of the basin and is increasingly abundant in the Eastern Mediterranean Sea where it reaches monstrous sizes compared to the maximum sizes reported from its native range. This contribution presents three well-documented new weight records from the Dodecanese Islands, Greece: one specimen weighing 8.5 kg from 2012, and two specimens weighing 8 and 9 kg, respectively, from 2021. The latter is also confirmed with other well-documented larger-size records, along with a physiological hypothesis suggesting how such large sizes are reached.
The Mediterranean Sea is home to over 2/3 of the world's charter boat traffic and hosts an estimated 1.5 million recreational boats. Studies elsewhere have demonstrated marinas as important hubs for ...the stepping-stone transfer of non-indigenous species (NIS), but these unique anthropogenic, and typically artificial habitats have largely gone overlooked in the Mediterranean as sources of NIS hot-spots. From April 2015 to November 2016, 34 marinas were sampled across the following Mediterranean countries: Spain, France, Italy, Malta, Greece, Turkey and Cyprus to investigate the NIS presence and richness in the specialized hard substrate material of these marina habitats. All macroinvertebrate taxa were collected and identified. Additionally, fouling samples were collected from approximately 600 boat-hulls from 25 of these marinas to determine if boats host diverse NIS not present in the marina. Here, we present data revealing that Mediterranean marinas indeed act as major hubs for the transfer of marine NIS, and we also provide evidence that recreational boats act as effective vectors of spread. From this wide-ranging geographical study, we report here numerous new NIS records at the basin, subregional, country and locality level. At the basin level, we report three NIS new to the Mediterranean Sea (
,
,
aff.
), and the re-appearance of two NIS previously known but currently considered extinct in the Mediterranean (
). We also compellingly update the distributions of many NIS in the Mediterranean Sea showing some recent spreading; we provide details for 11 new subregional records for NIS (
,
and
now present in the Western Mediterranean;
,
,
,
and
now present in the Central Mediterranean, and
,
and
in the Eastern Mediterranean). We also report 51 new NIS country records from recreational marinas: 12 for Malta, 10 for Cyprus, nine for Greece, six for Spain and France, five for Turkey and three for Italy, representing 32 species. Finally, we report 20 new NIS records (representing 17 species) found on recreational boat-hulls (mobile habitats), not yet found in the same marina, or in most cases, even the country. For each new NIS record, their native origin and global and Mediterranean distributions are provided, along with details of the new record. Additionally, taxonomic characters used for identification and photos of the specimens are also provided. These new NIS records should now be added to the relevant NIS databases compiled by several entities. Records of uncertain identity are also discussed, to assess the probability of valid non-indigenous status.
The silver-cheeked toadfish (Lagocephalus sceleratus) is an invasive species of highest concern. Its population must be controlled to mitigate its negative impacts on marine ecosystems, fishers, ...fisheries and human health. This study thoroughly investigates the biology, diet and catchability of the L. sceleratus stock from Finike, Turkey from March 2017 to February 2018 in order to better manage its invasion. A total of 751 specimens were sampled for this study with a M/F ratio of 1.25/1. The species becomes sexually mature at three and a half years of age, and Lm50 was 41.39 cm for males and 42.08 cm for females. Its spawning season in this region was from June to August, peaking in July. Its diet was mostly crustaceans in spring, fish in summer and both fish and crustaceans in winter. This species consumed a large amount of other pufferfish species, resulting in over a quarter of its fish diet. The trophic level of L. sceleratus was 4.41, demonstrating that it is indeed a top predator carnivore in the eastern Mediterranean Sea. Ingested fishing gear parts such as net pieces and hooks were found in about 10% of the fish. A slight modification of longlines using steel branch lines and a swivel hook resulted in double the catch per unit effort than standard longlines, so this technique can be used to target and control more of this invasive species, which is a national priority.
Purse seiners generally try to maximize their revenues by targeting multiple species, starting with the most valuable ones available. The technology and capacity of purse seiners can be exceptionally ...high for the stocks found in the Marmara Sea, Turkey’s only inland sea, due to its small size and nearly totally enclosed nature. Due to their large capabilities, they are responsible for the majority of catches and hence declines from this sea and thus should be held responsible for the poor state of marine stocks in the region. This study examines the catch compositions, expenses, and revenue sharing of purse seiners by using one representative vessel class for each of the four vessel length categories in the Marmara Sea. Surveys were also conducted with purse seine fishers to assess their perceptions related to fisheries management strategies along with their ideas for transitioning towards sustainable fisheries. As purse seiners are prominent stakeholders in the Marmara Sea fisheries, they should be incorporated into management guidance for effectiveness, along with other stakeholders. This study provides novel socio-economic data along with their perspectives, which may assist in improving policy decisions and capabilities. Our results demonstrate that purse seiners do not consider that their actions are a contributing factor to the current state of the fisheries, they trust in their amassed historical local knowledge, and seem to want to rebuild the resources, however only with minimal rules imposed on their sector.
Invasive species pose threats to either human health or inflict ecological and/or economic damage. The silver-cheeked toadfish (
Lagocephalus sceleratus
), a Lessepsian species, is one of the most ...harmful species in the Mediterranean Sea, because of its potent neurotoxin, impacts on marine biodiversity, and the increased costs and labor they inflict on fishers. Since the catch and consumption of this pufferfish is prohibited by almost all countries bordering the Mediterranean, they have now expanded into the entire Mediterranean and Black Sea. We performed a comprehensive study of
L. sceleratus
covering ecological aspects, growth, reproduction, diet and trophic level based on samples from southwestern coasts of Turkey. The estimated growth parameters were L
∞
= 88.7 cm, K = 0.27 year
-1
, C = 0.6 and WP = 0.1. Their sex-ratio was M/F = 1:0.69.
Lagocephalus sceleratus
appears to be a batch spawner with discontinuous oocyte recruitment and has different spawning seasons in the Eastern Mediterranean which seem to be based on temperature cues which get shorter in duration as one moves north from the Suez. We also report their first positive ecological trait, that they are controlling some other invasive species through their diets, such as lionfish, Red Sea goatfish, rabbitfish and longspine sea urchins, in addition to controlling themselves through cannibalism, which appears to be density-dependent. They are indeed a top predator in the region with a trophic level of 4.1. We suggest that targeted fishing using improved gear-types to reduce fishing gear damages are initiated, and that finding commercial markets for pufferfish could help to naturally fund ongoing control efforts.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The fisheries catch statistics that member countries report annually to the Food and Agriculture Organization of the United Nations were compared, for the years 1950 to 2010, with 'reconstructed', ...and more likely catch data from the Mediterranean coasts of mainland Spain, France, Italy and Turkey. Reconstructed catches were 2.6 times higher than those submitted to the FAO by these countries in the 1950s, and 1.8 times higher since 2000. If discarded by-catch is ignored they were 2.3 and 1.6 times higher, respectively. The contributors to the reconstructed catch from 1950 to 2010 were large-scale industrial fisheries (46%), discards (29%), artisanal fisheries (10%), recreational fisheries (9%) and subsistence fisheries (6%). The non-reported catch was high in all fishing sectors, including industrial, artisanal and recreational fisheries. The non-inclusion of discards in national and FAO statistics undermines the transition to ecosystem-based fisheries management, but needs to be overcome, as discards must be tracked before discarding itself is eliminated. The systematic underestimation of small-scale fisheries is part of a global phenomenon that will have to be overcome if the potential of these fisheries for sustainable exploitation of coastal systems is to be realized, perhaps in the context of reducing overall fishing capacity, which is excessive in the Mediterranean Sea as elsewhere in the world.Original Abstract: Se compararon las estadisticas de capturas pesqueras que los paises miembros declaran anualmente a la Organi-zacion de las Naciones Unidas para la Agricultura y la Alimentacion (FAO) para los anos 1950 a 2010, con las capturas "reconstruidas" (y mas probables) de las costas mediterraneas (excluyendo las islas) de Espana, Francia, Italia y Turquia. Las capturas reconstruidas fueron 2,6 veces superiores a los datos enviados a la FAO por estos paises en la decada de 1950, y 1,8 veces desde 2000, o 2,3 y 1,6 veces, respectivamente, sin tener en cuenta los descartes. Las capturas reconstruidas fueron obtenidas del sector industrial (es decir, pesca comercial de gran escala, con un 46 % de la captura total de 1950 a 2010), los descartes (29 %), la pesca artesanal (es decir, pesca comercial de pequena escala, 10%), la pesca recreativa (9 %) y la de sub-sistencia (6 %). Por lo tanto, a pesar de que las capturas no declaradas fueron importantes en todos los sectores pesqueros, in-cluyendo la pesca industrial, artesanal y recreativa, la no inclusion de los descartes en las estadisticas nacionales y de la FAO va en detrimento de la transicion hacia la aplicacion de una gestion pesquera basada en el ecosistema. Esto debe corregirse ya que el descarte debe ser documentado antes de que la practica de descartar pueda ser eliminada. En cuanto a la subestimacion sistematica de la pesca de pequena escala, es parte de un fenomeno global que debe ser corregido si se quiere materializar el potencial de estas pesquerias para la explotacion sostenible de los sistemas costeros, tal vez en el contexto de una reduccion global de la capacidad pesquera, que es excesiva, tanto en el mar Mediterraneo como en otras partes del mundo.
A newly established population of the fouling polychaete Spirobranchus cf. tetraceros is reported from the western Mediterranean (Valencia Port). Despite previous intensive surveys, this is the first ...record for the taxon in the Iberian Peninsula. Molecular analyses revealed that S. cf. tetraceros from Valencia are genetically identical to specimens from Heraklion, Crete, but different from those collected in the Red Sea and S. tetraceros sensu stricto from the type locality in Australia. Mediterranean and Red Sea S. cf. tetraceros form a well-supported monophyletic clade but are clearly distinct from New South Wales specimens of S. tetraceros. Our new molecular evidence supports the hypothesis that S. tetraceros is not a global invader of Australian origin but rather a large species complex in need of a comprehensive worldwide revision. These results highlight the importance of integrative taxonomic research for species with reported global distributions because these taxa may include cryptic invaders. An illustrated morphological account of the Valencia and Heraklion specimens and a taxonomic key for Spirobranchus species in the Mediterranean Sea are provided.
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