Zeitschriften und Ausgaben

Volumen 51 (2022): Heft 2 (June 2022)

Volumen 51 (2022): Heft 1 (March 2022)

Volumen 50 (2021): Heft 4 (December 2021)

Volumen 50 (2021): Heft 3 (September 2021)

Volumen 50 (2021): Heft 2 (June 2021)

Volumen 50 (2021): Heft 1 (March 2021)

Volumen 49 (2020): Heft 4 (December 2020)

Volumen 49 (2020): Heft 3 (September 2020)

Volumen 49 (2020): Heft 2 (June 2020)

Volumen 49 (2020): Heft 1 (March 2020)

Volumen 48 (2019): Heft 4 (December 2019)

Volumen 48 (2019): Heft 3 (September 2019)

Volumen 48 (2019): Heft 2 (June 2019)

Volumen 48 (2019): Heft 1 (March 2019)

Volumen 47 (2018): Heft 4 (December 2018)

Volumen 47 (2018): Heft 3 (September 2018)

Volumen 47 (2018): Heft 2 (June 2018)

Volumen 47 (2018): Heft 1 (March 2018)

Volumen 46 (2017): Heft 4 (December 2017)

Volumen 46 (2017): Heft 3 (September 2017)

Volumen 46 (2017): Heft 2 (June 2017)

Volumen 46 (2017): Heft 1 (March 2017)

Volumen 45 (2016): Heft 4 (December 2016)

Volumen 45 (2016): Heft 3 (September 2016)

Volumen 45 (2016): Heft 2 (June 2016)

Volumen 45 (2016): Heft 1 (March 2016)

Volumen 44 (2015): Heft 4 (December 2015)

Volumen 44 (2015): Heft 3 (September 2015)

Volumen 44 (2015): Heft 2 (June 2015)

Volumen 44 (2015): Heft 1 (March 2015)

Volumen 43 (2014): Heft 4 (December 2014)

Volumen 43 (2014): Heft 3 (September 2014)

Volumen 43 (2014): Heft 2 (June 2014)

Volumen 43 (2014): Heft 1 (March 2014)

Volumen 42 (2013): Heft 4 (December 2013)

Volumen 42 (2013): Heft 3 (September 2013)

Volumen 42 (2013): Heft 2 (June 2013)

Volumen 42 (2013): Heft 1 (March 2013)

Volumen 41 (2012): Heft 4 (December 2012)

Volumen 41 (2012): Heft 3 (September 2012)

Volumen 41 (2012): Heft 2 (June 2012)

Volumen 41 (2012): Heft 1 (March 2012)

Volumen 40 (2011): Heft 4 (December 2011)

Volumen 40 (2011): Heft 3 (September 2011)

Volumen 40 (2011): Heft 2 (June 2011)

Volumen 40 (2011): Heft 1 (March 2011)

Volumen 39 (2010): Heft 4 (December 2010)

Volumen 39 (2010): Heft 3 (September 2010)

Volumen 39 (2010): Heft 2 (June 2010)

Volumen 39 (2010): Heft 1 (March 2010)

Volumen 38 (2009): Heft 4 (December 2009)

Volumen 38 (2009): Heft 3 (September 2009)

Volumen 38 (2009): Heft 2 (June 2009)

Volumen 38 (2009): Heft 1 (March 2009)

Volumen 37 (2008): Heft 4 (December 2008)

Volumen 37 (2008): Heft 3 (September 2008)

Volumen 37 (2008): Heft 2 (June 2008)

Volumen 37 (2008): Heft 1 (March 2008)

Volumen 36 (2007): Heft 4 (December 2007)

Volumen 36 (2007): Heft 3 (September 2007)

Volumen 36 (2007): Heft 2 (June 2007)

Volumen 36 (2007): Heft 1 (March 2007)

Zeitschriftendaten
Format
Zeitschrift
eISSN
1897-3191
Erstveröffentlichung
23 Feb 2007
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 50 (2021): Heft 3 (September 2021)

Zeitschriftendaten
Format
Zeitschrift
eISSN
1897-3191
Erstveröffentlichung
23 Feb 2007
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

10 Artikel

Original research paper

Uneingeschränkter Zugang

Establishment and range expansion of non-native fish species facilitated by hot springs: the case study from the Upper Sakarya Basin (NW, Turkey)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 247 - 258

Zusammenfassung

Abstract

Non-native species can enter new habitats and ecosystems in a variety of ways. Suitable ecological conditions must exist for non-native species to reproduce in newly colonized habitats. Hot springs are suitable habitats for tropical, aquarium, and ornamental fish species. This paper presents the results of research on the distribution of non-native and native species in relation to environmental factors in the Upper Sakarya Basin, where several such springs are present. The fish fauna in the basin includes native (60% – 21 species, 14 of which are endemic) and non-native (40% – 14 species) fish species. Most of the non-native species (seven species) were found only in warm springs (minimum water temperature 16°C). In addition, 75 fish species belonging to 26 families were found throughout the Sakarya Basin. Hot springs were found to play an important role in the establishment of non-native species. The Kernel Density Estimation (KDE) results revealed that the non-native species density was high in the Upper Sakarya Basin where hot springs are common. This confirms that minimum and maximum temperatures are the main drivers of changes in the distribution of non-native fish species. Two aquarium fishes, Bujurguina vittata and Xiphophorus spp., are reported for the first time in the present study for inland waters of Turkey.

Schlüsselwörter

  • water temperature
  • aquarium species
  • Kernel Density Estimation
  • DISTLM
  • climate change
  • aquatic ecosystems
Uneingeschränkter Zugang

A review of occurrence, distribution and alien status of Notodiaphana atlantica Ortea, Moro and Espinosa, 2013 and Liloa mongii (Audouin, 1826) (Mollusca: Heterobranchia) in the Mediterranean Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 259 - 268

Zusammenfassung

Abstract

Notodiaphana atlantica and Liloa mongii are two cephalaspidean species described respectively from the Atlantic Ocean and the Red Sea, and considered widespread in their native ranges. Both species have also been recently recorded from the Mediterranean Sea, prompting some authors to consider them alien. Notwithstanding clear morphological differences in their shells, the two species have often been confused or misidentified in the literature, or specimens have been described with incorrect locality data. We hereby review the occurrence, distribution and status of both species in the Mediterranean Sea based on published data and examination of new material. Notodiaphana atlantica is considered a cryptogenic species with a range spanning from the western to eastern part of the basin. The presence of L. mongii in the Mediterranean is questioned until specimens that can be reliably assigned to this taxon or to any congeneric species are found in the area. Alien species inventories play an important role in regional policy and management decisions, thus requiring a high degree of confidence in the validity of species identification and their non-indigenous status. The present paper adds further evidence of the excess of “bibliographically introduced” alien records and reiterates the need for periodic re-evaluation of published data.

Schlüsselwörter

  • biological invasions
  • alien and cryptogenic species
  • faunal diversity
  • cephalaspideans
  • misidentifications
Uneingeschränkter Zugang

Growth parameters of Poecilia latipinna (Lesueur, 1821) (Actinopterygii, Poeciilidae) – an introduced species in brackish water of Wadi Al-Bahayes (Oman)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 269 - 277

Zusammenfassung

Abstract

This work is one of the first studies on the growth of Poecilia latipinna outside its natural habitat. The objective of our study was to investigate the growth parameters of the population of P. latipinna, which is an alien species in Oman (Wadi Al-Bahayes). The population structure of P. latipinna in Wadi Al-Bahayes (Oman; 23°40′47″N; 58°11′36″E) was studied in June and August 2020, using 124 fish. In the course of this study, the number of individuals of each sex, age, weight and size composition were determined. In addition, the total length–weight relationship (LRW) was calculated, as well as the von Bertalanffy growth equation. The mean growth performance (phi prime) and the condition factor were calculated. Males accounted for 37.10% and females for 62.90% of the population. The length–weight relationship and the von Bertalanffy growth equation were W = 0.0214 × L 2.7889 R2 = 0.9212, Lt = 11.46 (1 − e −0.127 (t + 2.71)) for males and Lt = 14.51 (1 − e−0.072 (t + 3.98)) for females. The mean growth performance and the condition factor were calculated as 1.22 for males and 1.18 for females and 1.54 for all specimens.

The study shows that the population of the species is characterized by a wide age range. Consequently, monitoring of this alien species is highly recommended.

Schlüsselwörter

  • Arabian Peninsula
  • alien species
  • sailfin molly
  • growth
  • LRW parameters
Uneingeschränkter Zugang

Historical review of Dutch Pectinariidae with Pectinaria belgica as a new taxon for the Netherlands (Annelida: Polychaeta: Pectinariidae)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 278 - 298

Zusammenfassung

Abstract

Two trumpet worms (Pectinariidae), which do not resemble the two known species: Lagis koreni Malmgren, 1866 and Amphictene auricoma (Müller, 1776), have recently been collected in the Dutch North Sea (Oyster Grounds). Their characteristics match those of Pectinaria belgica (Pallas, 1766), a species with a northern distribution. This paper summarizes the current state of knowledge of Dutch Pectinariidae and describes in detail the historical records of trumpet worms recorded in the Netherlands, along with the confusion around the species epithet belgica. Pectinaria belgica is reported here for the first time from the Dutch North Sea.

Schlüsselwörter

  • Annelida
  • Pectinariidae
  • history
  • review
  • diagnostics
  • distribution
  • Netherlands
Uneingeschränkter Zugang

Effects of seasonal changes and environmental factors on bioindicator bacteria levels in Çardak Lagoon, Çanakkale Strait, Turkey

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 299 - 309

Zusammenfassung

Abstract

Çardak Lagoon is one of the most important marine environments in the Turkish Strait system, which is home to a variety of organisms. The lagoon is currently under stress and faces the risk of heavy pollution. For this reason, the present state of the lagoon was monitored in this study. During sampling from October 2018 to June 2019, the levels of indicator microorganisms fluctuated up to 4.04 Log10 cfu 100 ml−1 and their presence was found to be higher in warmer seasons. The highest positive correlations were observed for total coliform levels with salinity and chemical oxygen demand, whereas the highest negative correlations were found between the levels of fecal coliforms, pH and temperature. E. coli and fecal streptococci showed moderate correlations with the environmental factors in all seasons. Although nitrite and nitrate (NO2 + NO3) were not significantly correlated with bacteria levels, they were present at elevated levels. Çardak Lagoon showed the lowest microbiological and chemical quality in the summer season, and this situation continued into the autumn season as a possible result of increased wastewater discharge and human activities. The lagoon should therefore be monitored regularly and precautions should be taken to prevent severe ecological deterioration.

Schlüsselwörter

  • Çardak Lagoon
  • pollution
  • bioindicator bacteria
  • environmental factors
  • Turkey
Uneingeschränkter Zugang

First record of straight-needle pteropod Creseis acicula Rang, 1828 bloom in the Çanakkale Strait (NE Aegean Sea, Turkey)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 310 - 324

Zusammenfassung

Abstract

Pteropods are marine pelagic calcifier mollusks sensitive to chemical changes in seawater due to their highly soluble aragonite shells. Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO2 concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod Creseis acicula Rang, 1828 bloom in the surface waters of the Ҫanakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the Ҫanakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently, the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the C. acicula bloom, rather than global atmospheric CO2 levels.

Schlüsselwörter

  • pteropod
  • Çanakkale Strait
  • marine ecology
  • bloom
  • anthropogenic impact
Uneingeschränkter Zugang

Demographics of great sturgeon (Huso huso) in Iranian waters of the Caspian Sea (2008–2010)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 325 - 332

Zusammenfassung

Abstract

Demographic data of the great sturgeon, Huso huso, from the Iranian coastal waters of the Caspian Sea were derived from measurements of individuals with a fork length ranging from 84 to 255 cm, obtained from commercial fisheries. The maximum age of fish caught in the south Caspian Sea was 30 years. The estimates of the asymptotic length L and the growth coefficient (K) were 265.255 cm and 0.062 per year for males and 275.78 cm and 0.08 per year for females, respectively. Total mortality rates obtained by Gulland's method were larger for males (0.64) than for females (0.46). Annual mortality rates were calculated as 47% for males and 37% for females. Data obtained in this study and their comparison with data from previous studies indicate that the great sturgeon stock is definitely exploited in an unsustainable manner.

Schlüsselwörter

  • age
  • growth
  • mortality
  • management
  • population dynamics
Uneingeschränkter Zugang

Philichthys xiphiae (Copepoda; Philichthyidae) – an interesting cranium parasite of the swordfish Xiphias gladius collected from the Baltic Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 333 - 337

Zusammenfassung

Abstract

The swordfish, Xiphias gladius Linnaeus, 1758, is a fish that sporadically enters the Baltic Sea. The present paper describes the identification of a very rarely recorded and poorly studied copepod of the family Philichthyidae – Philichthys xiphiae Steenstrup, 1862 – in a dead swordfish found on a sea beach in Dźwirzyno (Poland) in 2016. Philichthyidae are parasites inhabiting the sensory canals in the lateral line and skull bones of marine fish. In the present case, two P. xiphiae females were found, which constitutes the first record of the species in the Baltic area.

Schlüsselwörter

  • alien species
  • parasite
  • Baltic Sea
Uneingeschränkter Zugang

Effects of feed on fatty acid composition in muscles and gonads of the Chinese mitten crab (Eriocheir sinensis)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 338 - 351

Zusammenfassung

Abstract

In this study, the effects of different feeds on fatty acid composition in the Chinese mitten crab (Eriocheir sinensis) were investigated. The fatty acid composition in the Chinese mitten crab was significantly correlated with the type of feed source provided. Differences between the feed groups pertained mainly five fatty acids: oleic acid, linoleic acid, palmitic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of EPA and DHA was higher in the group of frozen trash fish than in the group of formulated feed. On the other hand, the content of oleic acid, linoleic acid and palmitic acid was higher in the formulated feed group than in the frozen trash fish group. There were significant differences in the nutritional value of the Chinese mitten crab reared under different feed sources, i.e. Chinese mitten crabs reared with the frozen trash fish feed were larger than those reared with the formulated feed, especially as regards the ω-3/ω-6 PUFA ratio and essential fatty acid levels.

Schlüsselwörter

  • Chinese mitten crab
  • fatty acids
  • formulated feed
  • frozen trash fish

Short communication

Uneingeschränkter Zugang

First record of the rare crab Asthenognathus atlanticus Monod, 1933 (Crustacea: Brachyura: Varunidae) in the North Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 352 - 358

Zusammenfassung

Abstract

Several species new to the area were collected while monitoring Dutch marine waters using a dredge. The varunid crab Asthenognathus atlanticus Monod, 1933 was recorded for the first time in the North Sea. Until 2008, this relatively rare crab was known from the west coast of Africa and the western Mediterranean to northern Brittany in the north. In recent years, its distribution range has expanded, as indicated by records from the Bay of the Seine and the area around Dieppe-Le Tréport. Our finding from Brown Bank (southern North Sea) indicates a further, northward expansion of its distribution range. We list the hosts with which the crab is associated. Earlier arguments for climate change as an explanation for the northward range expansion are supported.

Schlüsselwörter

  • range expansion
  • climate change
  • new record
  • commensalism
10 Artikel

Original research paper

Uneingeschränkter Zugang

Establishment and range expansion of non-native fish species facilitated by hot springs: the case study from the Upper Sakarya Basin (NW, Turkey)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 247 - 258

Zusammenfassung

Abstract

Non-native species can enter new habitats and ecosystems in a variety of ways. Suitable ecological conditions must exist for non-native species to reproduce in newly colonized habitats. Hot springs are suitable habitats for tropical, aquarium, and ornamental fish species. This paper presents the results of research on the distribution of non-native and native species in relation to environmental factors in the Upper Sakarya Basin, where several such springs are present. The fish fauna in the basin includes native (60% – 21 species, 14 of which are endemic) and non-native (40% – 14 species) fish species. Most of the non-native species (seven species) were found only in warm springs (minimum water temperature 16°C). In addition, 75 fish species belonging to 26 families were found throughout the Sakarya Basin. Hot springs were found to play an important role in the establishment of non-native species. The Kernel Density Estimation (KDE) results revealed that the non-native species density was high in the Upper Sakarya Basin where hot springs are common. This confirms that minimum and maximum temperatures are the main drivers of changes in the distribution of non-native fish species. Two aquarium fishes, Bujurguina vittata and Xiphophorus spp., are reported for the first time in the present study for inland waters of Turkey.

Schlüsselwörter

  • water temperature
  • aquarium species
  • Kernel Density Estimation
  • DISTLM
  • climate change
  • aquatic ecosystems
Uneingeschränkter Zugang

A review of occurrence, distribution and alien status of Notodiaphana atlantica Ortea, Moro and Espinosa, 2013 and Liloa mongii (Audouin, 1826) (Mollusca: Heterobranchia) in the Mediterranean Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 259 - 268

Zusammenfassung

Abstract

Notodiaphana atlantica and Liloa mongii are two cephalaspidean species described respectively from the Atlantic Ocean and the Red Sea, and considered widespread in their native ranges. Both species have also been recently recorded from the Mediterranean Sea, prompting some authors to consider them alien. Notwithstanding clear morphological differences in their shells, the two species have often been confused or misidentified in the literature, or specimens have been described with incorrect locality data. We hereby review the occurrence, distribution and status of both species in the Mediterranean Sea based on published data and examination of new material. Notodiaphana atlantica is considered a cryptogenic species with a range spanning from the western to eastern part of the basin. The presence of L. mongii in the Mediterranean is questioned until specimens that can be reliably assigned to this taxon or to any congeneric species are found in the area. Alien species inventories play an important role in regional policy and management decisions, thus requiring a high degree of confidence in the validity of species identification and their non-indigenous status. The present paper adds further evidence of the excess of “bibliographically introduced” alien records and reiterates the need for periodic re-evaluation of published data.

Schlüsselwörter

  • biological invasions
  • alien and cryptogenic species
  • faunal diversity
  • cephalaspideans
  • misidentifications
Uneingeschränkter Zugang

Growth parameters of Poecilia latipinna (Lesueur, 1821) (Actinopterygii, Poeciilidae) – an introduced species in brackish water of Wadi Al-Bahayes (Oman)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 269 - 277

Zusammenfassung

Abstract

This work is one of the first studies on the growth of Poecilia latipinna outside its natural habitat. The objective of our study was to investigate the growth parameters of the population of P. latipinna, which is an alien species in Oman (Wadi Al-Bahayes). The population structure of P. latipinna in Wadi Al-Bahayes (Oman; 23°40′47″N; 58°11′36″E) was studied in June and August 2020, using 124 fish. In the course of this study, the number of individuals of each sex, age, weight and size composition were determined. In addition, the total length–weight relationship (LRW) was calculated, as well as the von Bertalanffy growth equation. The mean growth performance (phi prime) and the condition factor were calculated. Males accounted for 37.10% and females for 62.90% of the population. The length–weight relationship and the von Bertalanffy growth equation were W = 0.0214 × L 2.7889 R2 = 0.9212, Lt = 11.46 (1 − e −0.127 (t + 2.71)) for males and Lt = 14.51 (1 − e−0.072 (t + 3.98)) for females. The mean growth performance and the condition factor were calculated as 1.22 for males and 1.18 for females and 1.54 for all specimens.

The study shows that the population of the species is characterized by a wide age range. Consequently, monitoring of this alien species is highly recommended.

Schlüsselwörter

  • Arabian Peninsula
  • alien species
  • sailfin molly
  • growth
  • LRW parameters
Uneingeschränkter Zugang

Historical review of Dutch Pectinariidae with Pectinaria belgica as a new taxon for the Netherlands (Annelida: Polychaeta: Pectinariidae)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 278 - 298

Zusammenfassung

Abstract

Two trumpet worms (Pectinariidae), which do not resemble the two known species: Lagis koreni Malmgren, 1866 and Amphictene auricoma (Müller, 1776), have recently been collected in the Dutch North Sea (Oyster Grounds). Their characteristics match those of Pectinaria belgica (Pallas, 1766), a species with a northern distribution. This paper summarizes the current state of knowledge of Dutch Pectinariidae and describes in detail the historical records of trumpet worms recorded in the Netherlands, along with the confusion around the species epithet belgica. Pectinaria belgica is reported here for the first time from the Dutch North Sea.

Schlüsselwörter

  • Annelida
  • Pectinariidae
  • history
  • review
  • diagnostics
  • distribution
  • Netherlands
Uneingeschränkter Zugang

Effects of seasonal changes and environmental factors on bioindicator bacteria levels in Çardak Lagoon, Çanakkale Strait, Turkey

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 299 - 309

Zusammenfassung

Abstract

Çardak Lagoon is one of the most important marine environments in the Turkish Strait system, which is home to a variety of organisms. The lagoon is currently under stress and faces the risk of heavy pollution. For this reason, the present state of the lagoon was monitored in this study. During sampling from October 2018 to June 2019, the levels of indicator microorganisms fluctuated up to 4.04 Log10 cfu 100 ml−1 and their presence was found to be higher in warmer seasons. The highest positive correlations were observed for total coliform levels with salinity and chemical oxygen demand, whereas the highest negative correlations were found between the levels of fecal coliforms, pH and temperature. E. coli and fecal streptococci showed moderate correlations with the environmental factors in all seasons. Although nitrite and nitrate (NO2 + NO3) were not significantly correlated with bacteria levels, they were present at elevated levels. Çardak Lagoon showed the lowest microbiological and chemical quality in the summer season, and this situation continued into the autumn season as a possible result of increased wastewater discharge and human activities. The lagoon should therefore be monitored regularly and precautions should be taken to prevent severe ecological deterioration.

Schlüsselwörter

  • Çardak Lagoon
  • pollution
  • bioindicator bacteria
  • environmental factors
  • Turkey
Uneingeschränkter Zugang

First record of straight-needle pteropod Creseis acicula Rang, 1828 bloom in the Çanakkale Strait (NE Aegean Sea, Turkey)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 310 - 324

Zusammenfassung

Abstract

Pteropods are marine pelagic calcifier mollusks sensitive to chemical changes in seawater due to their highly soluble aragonite shells. Increased acidity (reduced pH) of seawater causes difficulties in precipitating their shells and/or results in their dissolution, which is related to increased atmospheric CO2 concentrations and warming of seawater. They are therefore indicators of environmental changes. In this paper, we present the first record of the straight-needle pteropod Creseis acicula Rang, 1828 bloom in the surface waters of the Ҫanakkale Strait, Turkey (NE Aegean Sea), encountered in July 2020, when the highest sea surface temperatures and pH levels since 2007 were recorded. In coastal zones, such as the Ҫanakkale Strait, anthropogenic activity contributes significantly to environmental changes. Consequently, the increase in pH at elevated temperatures indicates an auxiliary factor (i.e. anthropogenic activity) that triggered the C. acicula bloom, rather than global atmospheric CO2 levels.

Schlüsselwörter

  • pteropod
  • Çanakkale Strait
  • marine ecology
  • bloom
  • anthropogenic impact
Uneingeschränkter Zugang

Demographics of great sturgeon (Huso huso) in Iranian waters of the Caspian Sea (2008–2010)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 325 - 332

Zusammenfassung

Abstract

Demographic data of the great sturgeon, Huso huso, from the Iranian coastal waters of the Caspian Sea were derived from measurements of individuals with a fork length ranging from 84 to 255 cm, obtained from commercial fisheries. The maximum age of fish caught in the south Caspian Sea was 30 years. The estimates of the asymptotic length L and the growth coefficient (K) were 265.255 cm and 0.062 per year for males and 275.78 cm and 0.08 per year for females, respectively. Total mortality rates obtained by Gulland's method were larger for males (0.64) than for females (0.46). Annual mortality rates were calculated as 47% for males and 37% for females. Data obtained in this study and their comparison with data from previous studies indicate that the great sturgeon stock is definitely exploited in an unsustainable manner.

Schlüsselwörter

  • age
  • growth
  • mortality
  • management
  • population dynamics
Uneingeschränkter Zugang

Philichthys xiphiae (Copepoda; Philichthyidae) – an interesting cranium parasite of the swordfish Xiphias gladius collected from the Baltic Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 333 - 337

Zusammenfassung

Abstract

The swordfish, Xiphias gladius Linnaeus, 1758, is a fish that sporadically enters the Baltic Sea. The present paper describes the identification of a very rarely recorded and poorly studied copepod of the family Philichthyidae – Philichthys xiphiae Steenstrup, 1862 – in a dead swordfish found on a sea beach in Dźwirzyno (Poland) in 2016. Philichthyidae are parasites inhabiting the sensory canals in the lateral line and skull bones of marine fish. In the present case, two P. xiphiae females were found, which constitutes the first record of the species in the Baltic area.

Schlüsselwörter

  • alien species
  • parasite
  • Baltic Sea
Uneingeschränkter Zugang

Effects of feed on fatty acid composition in muscles and gonads of the Chinese mitten crab (Eriocheir sinensis)

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 338 - 351

Zusammenfassung

Abstract

In this study, the effects of different feeds on fatty acid composition in the Chinese mitten crab (Eriocheir sinensis) were investigated. The fatty acid composition in the Chinese mitten crab was significantly correlated with the type of feed source provided. Differences between the feed groups pertained mainly five fatty acids: oleic acid, linoleic acid, palmitic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of EPA and DHA was higher in the group of frozen trash fish than in the group of formulated feed. On the other hand, the content of oleic acid, linoleic acid and palmitic acid was higher in the formulated feed group than in the frozen trash fish group. There were significant differences in the nutritional value of the Chinese mitten crab reared under different feed sources, i.e. Chinese mitten crabs reared with the frozen trash fish feed were larger than those reared with the formulated feed, especially as regards the ω-3/ω-6 PUFA ratio and essential fatty acid levels.

Schlüsselwörter

  • Chinese mitten crab
  • fatty acids
  • formulated feed
  • frozen trash fish

Short communication

Uneingeschränkter Zugang

First record of the rare crab Asthenognathus atlanticus Monod, 1933 (Crustacea: Brachyura: Varunidae) in the North Sea

Online veröffentlicht: 02 Sep 2021
Seitenbereich: 352 - 358

Zusammenfassung

Abstract

Several species new to the area were collected while monitoring Dutch marine waters using a dredge. The varunid crab Asthenognathus atlanticus Monod, 1933 was recorded for the first time in the North Sea. Until 2008, this relatively rare crab was known from the west coast of Africa and the western Mediterranean to northern Brittany in the north. In recent years, its distribution range has expanded, as indicated by records from the Bay of the Seine and the area around Dieppe-Le Tréport. Our finding from Brown Bank (southern North Sea) indicates a further, northward expansion of its distribution range. We list the hosts with which the crab is associated. Earlier arguments for climate change as an explanation for the northward range expansion are supported.

Schlüsselwörter

  • range expansion
  • climate change
  • new record
  • commensalism

Planen Sie Ihre Fernkonferenz mit Scienceendo