Türkiye’nin Batı Karadeniz kıyılarından 14 balık türü ıçin boy-ağırlık ilişkisi

In this study, the length-weight relationship (LWR) of 14 fish species including Merlangius merlangus (Linnaeus, 1758),Trachurus trachurus (Linnaeus, 1758), Mullus barbatus Linnaeus, 1758, Gobius niger Linnaeus, 1758, Scorpaena porcus (Linnaeus, 1758), Arnoglossus kessleri Schmidt, 1915, Uranoscopus scaber Linnaeus, 1758, Serranus hepatus (Linnaeus, 1758), Sygnathus thyphle Linnaeus, 1758, Aphia minuta (Risso, 1810), Trachinus draco Linnaeus, 1758, Parablennius tentacularis (Brünnich, 1768), Callionymus risso Lesueur 1814, Pomatoschistus marmoratus (Risso, 1810) caught from the western Black Sea coasts of Turkey was investigated. Sampling was carried out between 2017-2018 with a beam troll net with a span of 2 m. The sampling depth was between 10 m and 30 m. The minimum and maximum lengths and weights, length-weight relationships, a and b parameters and growth type (isometric or allometric) of the samples were determined. The b parameter of the length-weight relationship was determined between 2.58 and 3.586. A total of 3615 individuals belonging to 14 species were examined in the study. The most caugth species were M. barbatus (1118 individuals) and G. niger (1077 individuals). The coefficient of determination r2 value ranged from 0.79 (T. trachurus) to 0.99 (S. hepatus). It was determined that three species showed isometric growth, 4 species showed negative allometric growth and 7 species showed positive allometric growth.Bu çalışmada Batı Karadeniz kıyılarından yakalanan 14 balık türünün Merlangius merlangus (Linnaeus, 1758), Trachurus trachurus (Linnaeus, 1758), Mullus barbatus Linnaeus, 1758, Gobius niger Linnaeus, 1758, Scorpaena porcus (Linnaeus, 1758), Arnoglossus kessleri Schmidt, 1915, Uranoscopus scaber Linnaeus, 1758, Serranus hepatus (Linnaeus, 1758), Sygnathus thyphle Linnaeus, 1758, Aphia minuta (Risso, 1810), Trachinus draco Linnaeus, 1758, Parablennius tentacularis (Brünnich, 1768), Callionymus risso Lesueur 1814, Pomatoschistus marmoratus (Risso, 1810) boy-ağırlık ilişkisi belirlenmiştir. Örnekleme 2017-2018 yılları arasında 2 m açıklığa sahip beam troll ağıyla yapılmıştır. Örnekleme derinliği 10 m ile 30 m arasındadır. Örneklerin minimum ve maksimum boy ve ağırlıkları, boy-ağırlık ilişkileri, a ve b parametreleri ve büyüme tipi (izometrik veya allometrik) belirlenmiştir. Boy-ağırlık ilişkisinin b parametresi 2.58 ile 3.586 arasındadır. Çalışmada 14 türe ait toplam 3615 birey incelenmiştir. En çok yakalanan türler M. barbatus (1118 birey) ve G. niger (1077 birey) olmuştur. Belirleme katsayısı r2 değeri 0.79 (T. trachurus) ile 0.99 (S. hepatus) arasında değişmektedir. Üç türün izometrik, 4 türün negatif allometrik ve 7 türün pozitif allometrik büyüme gösterdiği tespit edilmiştir

Parasite infection in Serranus cabrilla (Perciformes, Serranidae): histopathological aspects and new host record for nematode genus Philometra from Aegean Sea, Turkey

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThis study was conducted to determine infection with nematode parasite Philometra sp. in gonads of Serranus cabrilla recorded in Izmir Gulf between October 2016 and July 2017. The overall prevalence was 14.46% and the mean intensity of infection 1.2 parasites per fish. The occurrence of philometrid infection on comber hosts was assessed according to several risk factors (fish length class, sex and season). Our findings suggest that the highest rates of parasite infection occur in larger sized fish, hermaphrodite individuals and during April month. The present report also revealed that marked hyperemia was the major findings of infected gonads of S. cabrilla, where parasitic nematodes caused a marked inflammatory reaction at the histopathological examination. As far as we know, this paper represents the first mention of genus Philometra in S. cabrilla from Turkey and the first presence of philometrid parasites in Aegean coast of Turkey. Furthermore, the present work is the first record of the effects of Philometra sp. parasitism on a serranid species in Izmir Gulf

Habitats and nekto-benthic communities of the bottom-trawl fishery developed on the continental shelf of the Balearic Islands

Director de la tesis doctoral: Dr. Massutí, E. (Enric). Ponente de la tesis doctoral: Dr. Bosch, R. (Rafael)Summary: The presence of biogenic benthic habitats in the continental shelf of the Balearic Islands is well known. In the circalittoral, outstanding due to their presence, the following can be found: the bottoms of calcareous red algae of the Corallinaceae family (known as maërl beds), considered particularly sensitive to the anthropogenic impacts; the crinoids beds, considered an essential habitat for the vital cycle of the fishing resources; or the Peyssonnelia beds, characterized by high biomasses of soft red algae, mainly of the Peyssonnelia genus. The bottom trawl fishery, developed in the continental shelf of the Archipelago takes place in these types of bottoms. In spite of this, and the negative effects of bottom trawling on benthic habitats, in the Balearic Islands, there is little information on the relationships between these habitats and the exploited species, whose biology and exploitation state is also unknown for the majority. This doctoral thesis studies the benthic habitats and the nekto-benthic communities exploited by the bottom trawl fishery developed on the continental shelf of the Balearic Islands. The main objectives include determining: the relationship between habitats and fishing resources, the main factors affecting the distribution of both, and how the presence of the main biogenic habitats affects the physiological condition of the associated fish species characterizing them. For the first time, the biology and exploitation state of some of the fishing resources characterizing these bottoms is studied, as well as the effect of changing the mesh geometry in the codend of the bottom trawl gears, from diamond to square, on the selectivity of this fishery. The results highlight that the presence of maërl and Peyssonnelia beds in the bottom trawl fishing grounds of the shallow shelf, and the crinoid beds in those of the deep shelf, is an important factor for the distribution of nekto- benthic fishing resources. Hydrodynamics influence the distribution of both habitats and fish. In this sense, fish size appears as a key trait for their distribution across gradients of change of both habitat and hydrodynamic regime. The study of the biology of characteristic fish species of the shallow shelf indicates that the most structurally complex biogenic habitats, showing the highest algae biomasses, such as maërl and Peyssonnelia beds, allow the individuals inhabiting them to have a better physiological condition than those distributed in habitats showing lower structural complexity and benthic biomass, such as the sandy bottoms. The main by-catch species of the bottom trawl fishery developed in the continental shelf of the Balearic Archipelago show a similar, or even more pronounced, level of overexploitation than the main target species of this fishery, which are the striped red mullet (Mullus surmuletus) and the hake (Merluccius merluccius). The use of square mesh in the codend substantially improves the selectivity of the bottom trawl gears, reducing the discarded catch and increasing the size at first capture of most species. However, these sizes are still smaller than the size of sexual maturity of most species, and in some cases, even smaller than the minimum landing sizes. The results highlight the importance of the presence of the biogenic benthic habitats for the populations of nekto-benthic organisms. Some of these habitats can play the role of oases where fish could face the energetic requirements of their vital cycle in a better physiological condition. In the Balearic Sea, an area standing out by its oligotrophy and where the most important commercial species show signs of overexploitation, the sustainability of fishing resources will depend on the ability to implement management measures aiming beyond the improvement of the current exploitation regime. They will have to take into account key aspects of the vital cycle of these species and the conservation of the habitats supporting them.Resum: La presència d‘hàbitats bentònics biogènics a la plataforma continental de les Illes Balears és ben coneguda. Al circalitoral hi destaquen per la seva presència: els fons d’algues vermelles calcàries de la família de les coral•linàcies (coneguts com a maërl), considerats especialment sensibles als impactes antropogènics; els fons de crinoïdeus, considerats un hàbitat essencial pel cicle vital dels recursos pesquers; o els fons d’avellanó, caracteritzats per presentar biomasses elevades d’algues vermelles toves, principalment del gènere Peyssonnelia. La pesquera de ròssec que es desenvolupa a la plataforma continental de l’Arxipèlag coincideix amb aquests tipus de fons. Malgrat això i els efectes negatius del ròssec sobre els hàbitats bentònics, a les Balears existeix poca informació sobre les relacions entre aquests hàbitats i les espècies explotades, de les quals tampoc se’n coneix la biologia i estat d’explotació de la majoria. Aquesta tesi doctoral estudia els hàbitats bentònics i les comunitats necto- bentòniques explotats per la pesquera de ròssec de la plataforma continental de les Illes Balears. Els principals objectius són determinar com es relacionen hàbitats i recursos pesquers, quins són els principals factors que afecten la distribució d’ambdós, i com afecta la presència dels principals hàbitats biogènics a la condició fisiològica d’algunes de les espècies de peixos que els caracteritzen. També s’estudia per primer cop la biologia i estat d’explotació d’alguns dels recursos pesquers característics d’aquests fons, així com l’efecte del canvi de la geometria de la malla del cop de les xarxes de ròssec, de ròmbica a quadrada, sobre la selectivitat d’aquesta pesquera. Els resultats destaquen que la presència dels fons de maërl i de Peyssonnelia als caladors de ròssec de la plataforma costanera, i els de crinoïdeus als de la plataforma profunda, actua com a un factor important per a la distribució dels recursos pesquers necto-bentònics. La hidrodinàmica condiciona tant la distribució dels hàbitats com la dels peixos. En aquest sentit, la mida dels peixos apareix com una característica clau en la seva distribució a través de gradients de canvi d’ambdós, hàbitat i règim hidrodinàmic. L’estudi de la biologia d’espècies íctiques característiques de la plataforma costanera, indica que els hàbitats biogènics estructuralment més complexes i amb major biomassa algal, com els de maërl i Peyssonnelia, permeten als individus que hi habiten gaudir d’una millor condició fisiològica que els que es distribueixen a hàbitats menys complexes i amb menor biomassa bentònica, com els fons de sorra. Les principals espècies ‘by-catch’ de la pesquera de ròssec que es desenvolupa a la plataforma continental de l’Arxipèlag Balear es troben en un nivell de sobreexplotació semblant, o inclús més pronunciat, que les principals espècies objectiu d’aquesta pesquera, el moll (Mullus surmuletus) i el lluç (Merluccius merluccius). La utilització de malla quadrada al cop suposa una clara millora en la selectivitat dels arts de ròssec, reduint la captura rebutjada i augmentant la talla de primera captura de la majoria d’espècies. Tot i així, aquestes talles segueixen essent menors que la talla de maduresa sexual de la majoria d’espècies, i en alguns casos, fins i tot menors que les talles mínimes legals. Els resultats remarquen la importància que té la presència dels hàbitats bentònics biogènics per a les poblacions d’organismes necto-bentònics. Alguns d’aquests hàbitats poden actuar com a oasis que permetrien als peixos afrontar amb una millor condició fisiològica els requeriments energètics del seu cicle vital. Al Mar Balear, una àrea que destaca per la seva oligotròfia i on les poblacions de les principals espècies comercials mostren signes de sobreexplotació, la sostenibilitat dels recursos pesquers dependrà de la capacitat d’implementar mesures de gestió amb objectius més enllà de la millora del règim d’explotació actual. Hauran de tenir en compte aspectes clau del cicle vital d’aquestes espècies i la conservació dels hàbitats que els hi donen suport.Resumen: La presencia de hábitats bentónicos biogénicos en la plataforma continental de las Illes Balears es bien conocida. En el circalitoral destacan por su presencia: los fondos de algas rojas calcáreas de la familia de las coralináceas (conocidos como maërl), considerados especialmente sensibles a los impactos antropogénicos; los fondos de crinoideos, considerados un hábitat esencial para el ciclo vital de los recursos pesqueros; o los fondos de avellanó, caracterizados por presentar biomasas elevadas de algas rojas blandas, principalmente del género Peyssonnelia. La pesquería de arrastre que se desarrolla en la plataforma continental del Archipiélago coincide con estos tipos de fondo. A pesar de ello y de los efectos negativos del arrastre sobre los hábitats bentónicos, en las Baleares existe poca información sobre las relaciones entre éstos hábitats y las especies explotadas, de las cuáles tampoco se conoce la biología y estado de explotación de la mayoría. Esta tesis doctoral estudia los hábitats bentónicos y las comunidades necto-bentónicas explotados por la pesquería de arrastre de la plataforma continental de las Illes Balears. Los principales objetivos son determinar cómo se relacionan hábitats y recursos pesqueros, cuáles son los principales factores que afectan la distribución de ambos y cómo afecta la presencia de los principales hábitats biogénicos a la condición fisiológica de las especies de peces que los caracterizan. También se estudia por primera vez la biología y estado de explotación de algunos de los recursos pesqueros característicos de estos fondos, así como el efecto del cambio de la geometría de la malla del copo de las redes de arrastre, de rómbica a cuadrada, sobre la selectividad de esta pesquería. Los resultados destacan que la presencia de los fondos de maërl y de Peyssonnelia en los caladeros de arrastre de la plataforma costera, y los de crinoideos en los de la plataforma profunda, actúa como un factor importante para la distribución de los recursos pesqueros necto-bentónicos. La hidrodinámica condiciona la distribución tanto de hábitats como de peces. En este sentido, el tamaño de los peces aparece como una característica clave para su distribución a través de gradientes de cambio de ambos, hábitat y régimen hidrodinámico. El estudio de la biología de especies ícticas características de la plataforma costera, indica que los hábitats biogénicos estructuralmente más complejos y con mayor biomasa algal, como los de maërl y Peyssonnelia, permiten que los individuos que los habitan disfruten de una mejor condición fisiológica que los que se distribuyen en hábitats menos complejos y con menor biomasa bentónica, como los fondos de arena. Las principales especies ‘by-catch’ de la pesquería de arrastre que se desarrolla en la plataforma continental del Archipiélago Balear se encuentran en un nivel de sobreexplotación similar, o incluso más pronunciado, que las principales especies objetivo de esta pesquería, el salmonete (Mullus surmuletus) y la merluza (Merluccius merluccius). La utilización de malla cuadrada en el copo supone una clara mejoría en la selectividad de los artes de arrastre, reduciendo la captura descartada y aumentando la talla de primera captura de la mayoría de especies. Aún así, estas tallas siguen siendo menores que la talla de madurez sexual de la mayoría de especies, y en algunos casos, incluso inferiores a la talla mínima legal. Los resultados remarcan la importancia que tiene la presencia de los hábitats bentónicos biogénicos para las poblaciones de organismos necto- bentónicos. Algunos de estos hábitats pueden actuar como oasis que permitirían a los peces afrontar con una mejor condición fisiológica los requerimientos energéticos de su ciclo vital. En el Mar Balear, un área que destaca por su oligotrofia y donde las poblaciones de las principales especies comerciales muestran signos de sobreexplotación, la sostenibilidad de los recursos pesqueros dependerá de la capacidad de implementar medidas de gestión con objetivos más allá de la mejora del régimen de explotación actual. Deberán tener en cuenta aspectos clave del ciclo vital de estas especies y la conservación de los hábitats que las sustentan

Age at maturity of Mediterranean marine fishes

In this review we collected data on the age at maturity (tm) and maximum reported age (tmax) for 235 stocks of Mediterranean marine fishes, belonging to 82 species, 37 families, 12 orders and 2 classes (Actinopterygii and Elasmobranchii). Among Actinopterygii (mean tm ± SD = 2.20 ± 1.43 y, n = 215), tm ranged from 0.3 y, for the common goby Pomatoschistus microps, to 12 y, for dusky grouper Epinephelus marginatus, while among Elasmobranchii (mean tm ± SD = 5.94 ± 2.47 y, n = 20), tm ranged between 2.7 y, for brown ray Raja miraletus, and 12 y for picked dogfish Squalus acanthias. Overall, the tmax ranged between 1 y, for transparent goby Aphia minuta, and 70 y, for wreckfish Polyprion americanus. The mean tmax of Actinopterygii (tmax ± SD = 10.14 ± 9.42 y) was lower than that of Elasmobranchii (tmax ± SD = 14.05 ± 8.47 y). The tm exhibited a strong positive linear relation with tmax for both Actinopterygii (logtm = 0.58 ´ logtmax – 0.25, r2 = 0.51, P < 0.001) and Elasmobranchii (logtm = 0.67 ´ logtmax – 0.006, r2 = 0.51, P = 0.007). The mean tm/tmax did not differ significantly with sex within Actinopterygii (ANOVA: F = 0.27, P = 0.60, n = 90; females: mean ± SD = 0.276 ± 0.143; males: mean ± SD = 0.265 ± 0.138) and Elasmobranchii (ANOVA: F = 1.44, P = 0.25, n = 10; females: mean ± SD = 0.499 ± 0.166; males: mean ± SD = 0.418 ± 0.133). Finally, the dimensionless ratio tm/tmax was significantly lower (ANOVA: F = 31.04, P < 0.001) for Actinopterygii (mean ± SD = 0.270 ± 0.135, n = 180) than for Elasmobranchii, (mean ± SD = 0.458 ± 0.152, n = 20), when stocks with combined sexes were excluded from the analysis

Bycatch and discards of commercial trawl fisheries in the south coast of Portugal

Bycatch and discards are a cause of great concern in commercial world fisheries, with important ecological, economic and conservation implications. With the recent inclusion of a discards ban (‘landing obligation’), in the reform of the EU CFP, these issues have gained a tremendous attention from the economic, scientific, political and social point of view. Demersal trawl fisheries off the southern coast of Portugal capture an extraordinary diversity of species and generate considerable amounts of bycatch and discards. Bycatch includes commercially valuable target-species and bycatch species with low or no commercial value, but the great majority consists of unmarketable species, that are discarded. Bony fishes are dominant in bycatch and discards and the most discarded are of low or no commercial value. The reasons for discarding are fundamentally economic in nature (lack of commercial value) for bycatch species, and legal and administrative (legal minimum landing size) for commercially important species. The study of the reproductive biology of Galeus melastomus, discarded by crustacean trawls, suggests that a minimum landing size should be established for this species, and explains the importance of such a study in the assessment and management of fisheries. The discovery of a new species of the ray Neoraja iberica n. sp. contributes to the knowledge of the local marine biodiversity in Portuguese waters and of the global marine biodiversity. The three cases of abnormal hermaphroditism recorded in Etmopterus spinax, are the first cases known to date of hermaphroditism in this species. There is a need to find solutions to the problem of bycatch and discards of trawl fisheries in the Algarve coast. A combination of technical, regulatory and economic measures to minimize bycatch and reduce discards, before implementing a ‘landing obligation’, is thought to be the best approach to apply in the southern Portuguese multispecies trawl fisheries

Implications for the future of fisheries as extractive industries in the creation of sustainable places: A case-study of the sustainable supply chain management of the Lipsi coastal small-scale capture fishery supply chain, Greece.

There exists a lack of information about many of the social, economic and ecological links within coastal Small-Scale Capture Fisheries; such knowledge is pertinent to the future sustainable exploitation and management of marine ecosystems by coastal communities. To conserve natural resources for future generations, sustainable management of natural resources is necessary. Sustainable resource management can help ensure that the use of resources does not cause an imbalance in the environment, and increasingly, sustainable management practices are being encouraged to preserve both animal and plant life for the benefit of future generations. Supply Chain Management is the active management of supply chain activities. It represents a conscious effort by supply chain managers to develop and run supply chains in the most effective way to meet Consumer demand. However,the vast majority of research and practice regarding sustainable supply chains has followed an instrumental logic, which has led firms and supply chain managers to place economic interests ahead of environmental and social interests. Ecologically Dominant Sustainable Supply Chain Management is a planning and decision-making process that seeks to coordinate and balance the social, economic and environmental demands of resource use to achieve long term sustainability. In this thesis, the Sustainable Supply Chain Management of the Lipsi Small-Scale Capture Fishery has been approached from a Sustainable Supply Chain Management perspective. The thesis interrogates the seafood supply chain of ‘place’ (The Municipality of Lipsi) by taking into consideration each ‘stage’ of the seafood supply chain; expressed here as Habitat, Assemblage, Fishery, Market and Consumer. In adopting q novel Conceptual Framework this thesis provides a platform for Small-Scale Capture Fishery research to move beyond ‘Catch to Market’ thinking (that treat’s the ocean as a ‘black box’ or homogenous entity) and helps to articulate the heterogeneous roles that coastal habitats play in provisioning Small-Scale Capture Fishery seafood supply chains. Furthermore, it aims to provide an intuitive and accessible platform for inter-disciplinary discussion, be that between business managers, ecologists, socio-ecological researchers, fisheries managers or local stakeholder

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