Fakultet for biovitenskap, fiskeri og økonomi
https://hdl.handle.net/10037/65
2024-03-19T01:04:01ZEstablishment of killer whale cell cultures and their responses to pollutant exposure
https://hdl.handle.net/10037/33173
Bjørneset, Juni<br />
The cosmopolitan apex predator killer whale (Orcinus orca) is one of the species worldwide with the highest levels of persistent organic pollutants (POPs) in their tissues. The knowledge of how POPs may affect the species is limited, likely due to the ethical, legal, and practical challenges of researching toxicology on free-ranging marine mammals. The use of in vitro models has proved to be a functional tool which may provide information of cellular responses to POPs exposure in marine mammals. Skin biopsies of killer whales were sampled from the Northern Norwegian fjords during aggregation of killer whales for foraging on spring spawning herring. Primary fibroblast-like cells were established from the dermis of 11 out of 13 killer whales sampled. Cytotoxic and gene transcript analysis were conducted on the fibroblast-like cells exposed to ecologically relevant concentrations of POPs, reflecting the 10 most abundant POPs found in Norwegian killer whales. The pollutants were applied at different concentrations to explore dose-dependent responses. Significant downregulation of the target gene CYP1A was observed at medium and highest exposure concentration, as well as non-significant tendencies of another downregulated gene (CD36) and seven upregulated genes (ADIPOQ, CYP4A, ERA, GR, PPARA, PPARG and THRA) at the highest concentration of POPs exposure. This study provides a successful establishment of killer whale fibroblast-like cells, as well as proven gene alterations of the cells exposed to POPs.<br />
2022-03-15T00:00:00ZEstablishment of killer whale cell cultures and their responses to pollutant exposureBjørneset, JuniThe cosmopolitan apex predator killer whale (Orcinus orca) is one of the species worldwide with the highest levels of persistent organic pollutants (POPs) in their tissues. The knowledge of how POPs may affect the species is limited, likely due to the ethical, legal, and practical challenges of researching toxicology on free-ranging marine mammals. The use of in vitro models has proved to be a functional tool which may provide information of cellular responses to POPs exposure in marine mammals. Skin biopsies of killer whales were sampled from the Northern Norwegian fjords during aggregation of killer whales for foraging on spring spawning herring. Primary fibroblast-like cells were established from the dermis of 11 out of 13 killer whales sampled. Cytotoxic and gene transcript analysis were conducted on the fibroblast-like cells exposed to ecologically relevant concentrations of POPs, reflecting the 10 most abundant POPs found in Norwegian killer whales. The pollutants were applied at different concentrations to explore dose-dependent responses. Significant downregulation of the target gene CYP1A was observed at medium and highest exposure concentration, as well as non-significant tendencies of another downregulated gene (CD36) and seven upregulated genes (ADIPOQ, CYP4A, ERA, GR, PPARA, PPARG and THRA) at the highest concentration of POPs exposure. This study provides a successful establishment of killer whale fibroblast-like cells, as well as proven gene alterations of the cells exposed to POPs.UiT Norges arktiske universitetUiT The Arctic University of NorwayRoutti, HeliDalmo, RoyBlévin, PierreMaster thesisMastergradsoppgaveExploring the gap between top-down sustainability objectives and perceived local sustainability challenges – the case of Senja Municipality
https://hdl.handle.net/10037/33135
Ahlquist, Ina Helene<br />
Achieving social, environmental, and economic sustainability has become the aim of nations and organizations across the globe. One of the attempts to operationalize sustainability is through the integration of the sustainable development goals in coastal governance. However, the perceived characteristics of challenges for sustainability, and thus also solutions to them, may differ depending on the point of view, and there may be a gap between perceptions of sustainability at different levels. Since perceptions of sustainability are shaped by how people interact with and understand the system they are part of, local key stakeholders were engaged at a specific local level, Senja Municipality, to explore local perceptions of sustainability. The stakeholders provided information about the context, including what they regarded as the conditions and limitations under which local sustainable development takes place.
Working towards sustainability is challenging in cases where governance efforts are not perceived as contributing to sustainability at the local level. In the case of Senja, local stakeholders arguably perceived their system as an SES where a more sustainable development could be found as compromises within environmental, social, and economic aspects, depending on the context. It concerned trade-offs where steps must be taken to reduce or hinder irreversible measures that later will be regretted. This has implications for local governance through how identifying sustainable compromises, therefore, becomes a governance challenge and a question about which processes and governance mechanisms are needed to do so. A result of shortcomings in managing the gap between top-down sustainability objectives and perceived local challenges for sustainability is that overall sustainability may be limited.<br />
2023-08-14T00:00:00ZExploring the gap between top-down sustainability objectives and perceived local sustainability challenges – the case of Senja MunicipalityAhlquist, Ina HeleneAchieving social, environmental, and economic sustainability has become the aim of nations and organizations across the globe. One of the attempts to operationalize sustainability is through the integration of the sustainable development goals in coastal governance. However, the perceived characteristics of challenges for sustainability, and thus also solutions to them, may differ depending on the point of view, and there may be a gap between perceptions of sustainability at different levels. Since perceptions of sustainability are shaped by how people interact with and understand the system they are part of, local key stakeholders were engaged at a specific local level, Senja Municipality, to explore local perceptions of sustainability. The stakeholders provided information about the context, including what they regarded as the conditions and limitations under which local sustainable development takes place.
Working towards sustainability is challenging in cases where governance efforts are not perceived as contributing to sustainability at the local level. In the case of Senja, local stakeholders arguably perceived their system as an SES where a more sustainable development could be found as compromises within environmental, social, and economic aspects, depending on the context. It concerned trade-offs where steps must be taken to reduce or hinder irreversible measures that later will be regretted. This has implications for local governance through how identifying sustainable compromises, therefore, becomes a governance challenge and a question about which processes and governance mechanisms are needed to do so. A result of shortcomings in managing the gap between top-down sustainability objectives and perceived local challenges for sustainability is that overall sustainability may be limited.UiT The Arctic University of NorwayUiT Norges arktiske universitetSønvisen, Signe AnnieJohnsen, Jahn PetterMaster thesisMastergradsoppgaveA Novel Biosurfactant-Based Oil Spill Response Dispersant for Efficient Application under Temperate and Arctic Conditions
https://hdl.handle.net/10037/33127
Farooq, Umer; Szczybelski Ciordia, Ariadna Sabina; Ferreira, Frederico Castelo; Faria, Nuno Torres; Netzer, Roman<br />
Synthetic oil spill dispersants have become essential in offshore oil spill response strategies. However, their use raises significant concerns regarding toxicity to phyto- and zooplankton and other marine organisms, especially in isolated and vulnerable areas such as the Arctic and shorelines. Sustainable alternatives may be developed by replacing the major active components of commercial dispersants with their natural counterparts. During this study, interfacial properties of different types of glycolipid-based biosurfactants (rhamnolipids, mannosylerythritol lipids, and trehalose lipids) were explored in a crude oil–seawater system. The best-performing biosurfactant was further mixed with different nontoxic components of Corexit 9500A, and the interfacial properties of the most promising dispersant blend were further explored with various types of crude oils, weathered oil, bunker, and diesel fuel in natural seawater. Our findings indicate that the most efficient dispersant formulation was achieved when mannosylerythritol lipids (MELs) were mixed with Tween 80 (T). The MELs–T dispersant blend significantly reduced the interfacial tension (IFT) of various crude oils in seawater with results comparable to those obtained with Corexit 9500A. Importantly, no leaching or desorption of MELs–T components from the crude oil–water interface was observed. Furthermore, for weathered and more viscous asphaltenic bunker fuel oil, IFT results with the MELs–T dispersant blend surpassed those obtained with Corexit 9500A. This dispersant blend also demonstrated effectiveness at different dosages (dispersant-to-oil ratio (DOR)) and under various temperature conditions. The efficacy of the MELs–T dispersant was further confirmed by standard baffled flask tests (BFTs) and Mackay–Nadeau–Steelman (MNS) tests. Overall, our study provides promising data for the development of effective biobased dispersants, particularly in the context of petroleum exploitation in subsea resources and transportation in the Arctic.<br />
2024-02-15T00:00:00ZA Novel Biosurfactant-Based Oil Spill Response Dispersant for Efficient Application under Temperate and Arctic ConditionsFarooq, UmerSzczybelski Ciordia, Ariadna SabinaFerreira, Frederico CasteloFaria, Nuno TorresNetzer, RomanSynthetic oil spill dispersants have become essential in offshore oil spill response strategies. However, their use raises significant concerns regarding toxicity to phyto- and zooplankton and other marine organisms, especially in isolated and vulnerable areas such as the Arctic and shorelines. Sustainable alternatives may be developed by replacing the major active components of commercial dispersants with their natural counterparts. During this study, interfacial properties of different types of glycolipid-based biosurfactants (rhamnolipids, mannosylerythritol lipids, and trehalose lipids) were explored in a crude oil–seawater system. The best-performing biosurfactant was further mixed with different nontoxic components of Corexit 9500A, and the interfacial properties of the most promising dispersant blend were further explored with various types of crude oils, weathered oil, bunker, and diesel fuel in natural seawater. Our findings indicate that the most efficient dispersant formulation was achieved when mannosylerythritol lipids (MELs) were mixed with Tween 80 (T). The MELs–T dispersant blend significantly reduced the interfacial tension (IFT) of various crude oils in seawater with results comparable to those obtained with Corexit 9500A. Importantly, no leaching or desorption of MELs–T components from the crude oil–water interface was observed. Furthermore, for weathered and more viscous asphaltenic bunker fuel oil, IFT results with the MELs–T dispersant blend surpassed those obtained with Corexit 9500A. This dispersant blend also demonstrated effectiveness at different dosages (dispersant-to-oil ratio (DOR)) and under various temperature conditions. The efficacy of the MELs–T dispersant was further confirmed by standard baffled flask tests (BFTs) and Mackay–Nadeau–Steelman (MNS) tests. Overall, our study provides promising data for the development of effective biobased dispersants, particularly in the context of petroleum exploitation in subsea resources and transportation in the Arctic.ACS PublicationsJournal articleTidsskriftartikkelPeer reviewedFarooq, Szczybelski Ciordia, Ferreira, Faria, Netzer. A Novel Biosurfactant-Based Oil Spill Response Dispersant for Efficient Application under Temperate and Arctic Conditions. ACS Omega. 2024:1-13ACS OmegaBioglider: an integrated glider solution for enhancing environmental knowledge
https://hdl.handle.net/10037/33124
Poncon, Yves; Mortier, Laurent; Picheral, Marc; Fitzek, Peer; Hayes, Dan; Abdi, Ehsan; Zdroik, Jakub; Beszczynska-Möller, Agnieszka; Coindat, Jerome; Dunn, Muriel Barbara; Ramasco, Virginie; Thorstensen, Morten; Camus, Lionel; Priou, Pierre; Basedow, Sünnje Linnéa; Pedersen, Geir; Arbi, Tarak; Geller, Benoit<br />
This paper presents a technological solution for the observation and monitoring of the marine ecosystem. Three complementary devices, one optic imaging and one scientific acoustic instrument as well as one acoustic communication modem, have been integrated on glider platforms, providing qualitative and quantitative zooplankton and fish ecology observations, which are especially relevant in Nordic and Arctic polar regions. This ‘Bioglider’ solution has been tested on two available gliders. Another essential platform component for ocean observing are subsurface mooring lines which can complement glider observations in terms of temporal scales. Most of the time, they cannot have surface expressions in these regions because of sea-ice cover or harsh sea conditions, prohibiting real time data delivery. Underwater acoustic communication can allow the glider to serve as a data messenger, retrieving data from the moorings, complementing its measuring capacities. The Bioglider data transmission protocol and the Hydro-Acoustic Link Simulator were successfully tested in different test scenarios. We also developed a MIMO (Multi-input Multi-output) acoustic platform and obtained theoretical results about equalizing structures to face the harsh multipath acoustic underwater propagation. These developments address the challenges posed by sea-ice cover, harsh sea conditions, and maritime traffic, ensuring near real-time data delivery and enabling comprehensive observations of the marine environment. The Bioglider sensor solution and Bioglider data transmission solution have been implemented or designed for the existing and commercially available gliders and are validated by first promising results from an operational, technological and scientific point of view.<br />
Source at <a href=https://hal.science/hal-04177859>https://hal.science/hal-04177859</a>.<br />
2023-12-11T00:00:00ZBioglider: an integrated glider solution for enhancing environmental knowledgePoncon, YvesMortier, LaurentPicheral, MarcFitzek, PeerHayes, DanAbdi, EhsanZdroik, JakubBeszczynska-Möller, AgnieszkaCoindat, JeromeDunn, Muriel BarbaraRamasco, VirginieThorstensen, MortenCamus, LionelPriou, PierreBasedow, Sünnje LinnéaPedersen, GeirArbi, TarakGeller, BenoitThis paper presents a technological solution for the observation and monitoring of the marine ecosystem. Three complementary devices, one optic imaging and one scientific acoustic instrument as well as one acoustic communication modem, have been integrated on glider platforms, providing qualitative and quantitative zooplankton and fish ecology observations, which are especially relevant in Nordic and Arctic polar regions. This ‘Bioglider’ solution has been tested on two available gliders. Another essential platform component for ocean observing are subsurface mooring lines which can complement glider observations in terms of temporal scales. Most of the time, they cannot have surface expressions in these regions because of sea-ice cover or harsh sea conditions, prohibiting real time data delivery. Underwater acoustic communication can allow the glider to serve as a data messenger, retrieving data from the moorings, complementing its measuring capacities. The Bioglider data transmission protocol and the Hydro-Acoustic Link Simulator were successfully tested in different test scenarios. We also developed a MIMO (Multi-input Multi-output) acoustic platform and obtained theoretical results about equalizing structures to face the harsh multipath acoustic underwater propagation. These developments address the challenges posed by sea-ice cover, harsh sea conditions, and maritime traffic, ensuring near real-time data delivery and enabling comprehensive observations of the marine environment. The Bioglider sensor solution and Bioglider data transmission solution have been implemented or designed for the existing and commercially available gliders and are validated by first promising results from an operational, technological and scientific point of view.IEEEJournal articleTidsskriftartikkelPeer reviewedPoncon, Mortier L, Picheral M, Fitzek P, Hayes D, Abdi E, Zdroik J, Beszczynska-Möller A, Coindat J, Dunn MB, Ramasco V, Thorstensen M, Camus L, Priou P, Basedow SL, Pedersen G, Arbi T, Geller B. Bioglider: an integrated glider solution for enhancing environmental knowledge. IEEE Journal of Oceanic Engineering. 2023;OCEANS2023GulfCoastIEEE Journal of Oceanic EngineeringOverskudd og ressursrente -mer for Nord-Norge?
https://hdl.handle.net/10037/33123
Flaaten, Ola; Heen, Eirik Eriksen; Heen, Knut<br />
Artikkelen beskriver utviklingen i fiskeri- og havbruksnæringen i Nord-Norge, med spesiell vekt på Finnmark og Nord-Troms. Norsk økonomisk sone har her det biologiske grunnlaget for landets viktigste fiskerier. Fiskeriene har gått fra å være en åpen næring til en lukket og eksklusiv «klubb». Konsekvensene for næringen i Nord-Norge har vært sentralisering i færre enheter og svekking av mange lokalsamfunn. Over tiår har Finnmark tapt nasjonale andeler i de nasjonale fiskeriene, og fylket har i dag, til tross for en vesentlig andel av norsk lakseoppdrett, ingen del i de store eierinntektene innen oppdrett. Hvilket handlingsrom man har for å styrke fiskeri- og havbruksnæringen i det nordlige Norge, diskuteres, blant annet ved en analyse av inntekt og sysselsetting i torskefiskeriene.<br />
2023-01-01T00:00:00ZOverskudd og ressursrente -mer for Nord-Norge?Flaaten, OlaHeen, Eirik EriksenHeen, KnutArtikkelen beskriver utviklingen i fiskeri- og havbruksnæringen i Nord-Norge, med spesiell vekt på Finnmark og Nord-Troms. Norsk økonomisk sone har her det biologiske grunnlaget for landets viktigste fiskerier. Fiskeriene har gått fra å være en åpen næring til en lukket og eksklusiv «klubb». Konsekvensene for næringen i Nord-Norge har vært sentralisering i færre enheter og svekking av mange lokalsamfunn. Over tiår har Finnmark tapt nasjonale andeler i de nasjonale fiskeriene, og fylket har i dag, til tross for en vesentlig andel av norsk lakseoppdrett, ingen del i de store eierinntektene innen oppdrett. Hvilket handlingsrom man har for å styrke fiskeri- og havbruksnæringen i det nordlige Norge, diskuteres, blant annet ved en analyse av inntekt og sysselsetting i torskefiskeriene.Orkana forlagChapterBokkapittelFlaaten O, Heen EE, Heen K: Overskudd og ressursrente -mer for Nord-Norge?. In: Nilsen R, Brox O, Eythórsson E, Jentoft S. Allmenningsressurser i nord - fellesskap og grunnrente, 2023. Orkana Forlag p. 101-134Cross-cultural co-creation of a tourist site: the emic and etic makings
https://hdl.handle.net/10037/33121
Lee, Young-Sook; Mathisen, Line; Søreng, Siri Ulfsdatter<br />
This chapter discusses how an Arctic destination, North Cape, is co-created through time and space aided by tourists' engagement. We present two cases: (1) Thai visitors to the North Cape; and (2) North Cape as a brand in South Korea, drawing on qualitative methods. We argue that cross-cultural co-creation in tourism experiences depends on the knowledge of different emic and etic perceptions of the site. These diverse emic and etic perceptions of the site, operand and operant resources of the visitors emerge in their co-creation of experiences. Implications for researchers and practitioners are provided.<br />
2023-10-17T00:00:00ZCross-cultural co-creation of a tourist site: the emic and etic makingsLee, Young-SookMathisen, LineSøreng, Siri UlfsdatterThis chapter discusses how an Arctic destination, North Cape, is co-created through time and space aided by tourists' engagement. We present two cases: (1) Thai visitors to the North Cape; and (2) North Cape as a brand in South Korea, drawing on qualitative methods. We argue that cross-cultural co-creation in tourism experiences depends on the knowledge of different emic and etic perceptions of the site. These diverse emic and etic perceptions of the site, operand and operant resources of the visitors emerge in their co-creation of experiences. Implications for researchers and practitioners are provided.Edward Elgar PublishingChapterBokkapittelLee YS, Mathisen L, Søreng SUS: Cross-cultural co-creation of a tourist site: the emic and etic makings. In: Rather, Ramkissoon H. Handbook of Customer Engagement in Tourism Marketing, 2023. Edward Elgar Publishing p. 218-230Mining various genomic resources to resolve old alpha-taxonomy questions: A test of the species hypothesis of the Proteocephalus longicollis species complex (Cestoda: Platyhelminthes) from salmonid fishes
https://hdl.handle.net/10037/33099
Brabec, Jan; Rochat, Eloïse Coralie; Knudsen, Rune; Scholz, Tomas; Costa, Isabel Blasco<br />
High-throughput sequencing strategies became commonly employed to study non-model parasites, but
the corresponding genomes and transcriptomes were seldom mined following the original publication.
Similar to the data generated with genome skimming techniques based on shallow-depth shotgun gen omes, various genomic and transcriptomic resources can be screened for useful molecular phylogenetic
markers traditionally characterised with Sanger sequencing. Here, we provide an example of a strategy
using reduced-representation genomic as well as transcriptomic data to obtain broad insights into the
molecular diversity of the cestode Proteocephalus longicollis, a common parasite of salmonids distributed
throughout the Holarctic region. We extract popular mitochondrial and nuclear ribosomal markers from
various genomic resources for hundreds of parasite specimens from multiple European whitefish popu lations and compare those with Proteocephalus representatives from other species of salmonids and var ious geographical regions. In contrast with the previous morphology-based assessments, molecular
phylogeny reveals a high degree of genetic divergence between Proteocephalus isolates from different sal monids, contrastingly low genetic differentiation within the parasite’s populations hosted by the
European whitefish (Coregonus lavaretus species complex), and a sister species relationship of
Proteocephalus from European whitefish and Proteocephalus percae, a parasite of European perch (Perca
fluviatilis). Proteocephalus spp. from North American lake whitefish, brown trout and Arctic charr each
formed clearly distinct lineages. These results advance our understanding of the interrelationships of
the Proteocephalus-aggregate, a well-recognized clade of Holarctic freshwater fish proteocephalids, and
support resurrection of some of the nominal species of Proteocephalus, including Proteocephalus exiguus
La Rue, 1911 from North American coregonids and Proteocephalus fallax La Rue, 1911 from European C.
lavaretus, reserving Proteocephalus longicollis (Zeder, 1800) exclusively for parasites of Salmo trutta.<br />
2023-01-24T00:00:00ZMining various genomic resources to resolve old alpha-taxonomy questions: A test of the species hypothesis of the Proteocephalus longicollis species complex (Cestoda: Platyhelminthes) from salmonid fishesBrabec, JanRochat, Eloïse CoralieKnudsen, RuneScholz, TomasCosta, Isabel BlascoHigh-throughput sequencing strategies became commonly employed to study non-model parasites, but
the corresponding genomes and transcriptomes were seldom mined following the original publication.
Similar to the data generated with genome skimming techniques based on shallow-depth shotgun gen omes, various genomic and transcriptomic resources can be screened for useful molecular phylogenetic
markers traditionally characterised with Sanger sequencing. Here, we provide an example of a strategy
using reduced-representation genomic as well as transcriptomic data to obtain broad insights into the
molecular diversity of the cestode Proteocephalus longicollis, a common parasite of salmonids distributed
throughout the Holarctic region. We extract popular mitochondrial and nuclear ribosomal markers from
various genomic resources for hundreds of parasite specimens from multiple European whitefish popu lations and compare those with Proteocephalus representatives from other species of salmonids and var ious geographical regions. In contrast with the previous morphology-based assessments, molecular
phylogeny reveals a high degree of genetic divergence between Proteocephalus isolates from different sal monids, contrastingly low genetic differentiation within the parasite’s populations hosted by the
European whitefish (Coregonus lavaretus species complex), and a sister species relationship of
Proteocephalus from European whitefish and Proteocephalus percae, a parasite of European perch (Perca
fluviatilis). Proteocephalus spp. from North American lake whitefish, brown trout and Arctic charr each
formed clearly distinct lineages. These results advance our understanding of the interrelationships of
the Proteocephalus-aggregate, a well-recognized clade of Holarctic freshwater fish proteocephalids, and
support resurrection of some of the nominal species of Proteocephalus, including Proteocephalus exiguus
La Rue, 1911 from North American coregonids and Proteocephalus fallax La Rue, 1911 from European C.
lavaretus, reserving Proteocephalus longicollis (Zeder, 1800) exclusively for parasites of Salmo trutta.ElsevierJournal articleTidsskriftartikkelPeer reviewedBrabec, Rochat EC, Knudsen R, Scholz T, Costa IB. Mining various genomic resources to resolve old alpha-taxonomy questions: A test of the species hypothesis of the Proteocephalus longicollis species complex (Cestoda: Platyhelminthes) from salmonid fishes. International Journal for Parasitology. 2023;53(4):197-205International Journal for ParasitologyComparative analysis of the cytoarchitecture of the excretory bladder of adult Digenea (Platyhelminthes) with consideration of the presence of mineralized excretory corpuscles in marine and freshwater adult worms
https://hdl.handle.net/10037/33095
Poddubnaya, Larisa G.; Hemmingsen, Willy; MacKenzie, Ken<br />
The ultrastructural differences are shown between the cytoarchitecture of the excretory bladder and excretory inclusions in four digenean species, two azygiids, the marine Otodistomum cestoides and the freshwater Azygia lucii, the marine derogenid Derogenes varicus and the freshwater allocreadiid Acrolichanus auriculatus. The unusual cytoarchitecture of the bladder epithelium of the azygiid digeneans, consisting along its entire length of two alternating, morphologically different zones, tegumental and cellular excretory epithelial zones, connected by septate junctions, has recorded for the first time for the Digenea and, in general, for the Neodermata. It, possible, suggests the participation of the tegumental distal cytoplasmic layer in the formation of their excretory bladder epithelium. Like most digeneans, the excretory bladder of A. auriculatus and D. varicus has a syncytial epithelial lining. Based on available literature and our own results, we can confirm the presence of the excretory corpuscles in adult marine digeneans and their absence from freshwater species, regardless of the digenean localization in their host. The present study shown that in marine digeneans, the excretory corpuscles are associated with specialized excretory cells or excretory syncytial epithelium. Ultrastructural data were obtained on the possible growth of the excretory bladder epithelium due to the migration of undifferentiated cells into the epithelial lining in studied marine species. We may assume that the bladder epithelium of marine adult digeneans specializes, in addition to the excretory function, in osmoregulatory function.<br />
2024-02-01T00:00:00ZComparative analysis of the cytoarchitecture of the excretory bladder of adult Digenea (Platyhelminthes) with consideration of the presence of mineralized excretory corpuscles in marine and freshwater adult wormsPoddubnaya, Larisa G.Hemmingsen, WillyMacKenzie, KenThe ultrastructural differences are shown between the cytoarchitecture of the excretory bladder and excretory inclusions in four digenean species, two azygiids, the marine Otodistomum cestoides and the freshwater Azygia lucii, the marine derogenid Derogenes varicus and the freshwater allocreadiid Acrolichanus auriculatus. The unusual cytoarchitecture of the bladder epithelium of the azygiid digeneans, consisting along its entire length of two alternating, morphologically different zones, tegumental and cellular excretory epithelial zones, connected by septate junctions, has recorded for the first time for the Digenea and, in general, for the Neodermata. It, possible, suggests the participation of the tegumental distal cytoplasmic layer in the formation of their excretory bladder epithelium. Like most digeneans, the excretory bladder of A. auriculatus and D. varicus has a syncytial epithelial lining. Based on available literature and our own results, we can confirm the presence of the excretory corpuscles in adult marine digeneans and their absence from freshwater species, regardless of the digenean localization in their host. The present study shown that in marine digeneans, the excretory corpuscles are associated with specialized excretory cells or excretory syncytial epithelium. Ultrastructural data were obtained on the possible growth of the excretory bladder epithelium due to the migration of undifferentiated cells into the epithelial lining in studied marine species. We may assume that the bladder epithelium of marine adult digeneans specializes, in addition to the excretory function, in osmoregulatory function.ElsevierJournal articleTidsskriftartikkelPeer reviewedPoddubnaya, Hemmingsen, MacKenzie. Comparative analysis of the cytoarchitecture of the excretory bladder of adult Digenea (Platyhelminthes) with consideration of the presence of mineralized excretory corpuscles in marine and freshwater adult worms. Zoologischer Anzeiger. 2024;309:28-36Zoologischer AnzeigerSimple pot modification improves catch efficiency and species composition in a tropical estuary mud crab (Scylla serrata) fishery
https://hdl.handle.net/10037/33086
Madhu, V.R.; Anand, Sreelakshmi B.; Cerbule, Kristine; Herrmann, Bent<br />
Pots are widely used fishing gear type for targeting different crustacean and fish species. Pot entrance size and design are among the most important technical parameters that influence the catch efficiency of certain species. An optimal pot entrance design should allow an efficient entry for the target species while preventing subsequent escape. The tropical estuary pot fishery targeting mud crab (Scylla serrata) in Vembanad Lake, India, employs rectangular pots with rectangular-shaped entrances. Low catch rates for target species and high bycatch rates are observed in this fishery. This study was carried out to investigate if a simple pot modification by extending the entrance of the traditional pots, can improve the catch efficiency of mud crab. Further, we estimated and compared the catch composition in this small-scale fishery using the traditional and modified entrance pots. The results showed that the catch efficiency for all sizes of mud crab is on average more than six times higher with the modified entrance pots compared to the traditional pots (622% (CI: 344–1867%)). However, significant quantities of juvenile crabs are caught in modified pots. Further, the bycatch ratio was significantly reduced for modified compared to the standard entrance pots in this fishery. These results show that such pot modifications have potential to significantly improve the catches in mud crab pot fisheries without increase in capture of bycatch species. However, additional mechanisms for excluding undersized crabs from pot catches should be investigated.<br />
2023-05-08T00:00:00ZSimple pot modification improves catch efficiency and species composition in a tropical estuary mud crab (Scylla serrata) fisheryMadhu, V.R.Anand, Sreelakshmi B.Cerbule, KristineHerrmann, BentPots are widely used fishing gear type for targeting different crustacean and fish species. Pot entrance size and design are among the most important technical parameters that influence the catch efficiency of certain species. An optimal pot entrance design should allow an efficient entry for the target species while preventing subsequent escape. The tropical estuary pot fishery targeting mud crab (Scylla serrata) in Vembanad Lake, India, employs rectangular pots with rectangular-shaped entrances. Low catch rates for target species and high bycatch rates are observed in this fishery. This study was carried out to investigate if a simple pot modification by extending the entrance of the traditional pots, can improve the catch efficiency of mud crab. Further, we estimated and compared the catch composition in this small-scale fishery using the traditional and modified entrance pots. The results showed that the catch efficiency for all sizes of mud crab is on average more than six times higher with the modified entrance pots compared to the traditional pots (622% (CI: 344–1867%)). However, significant quantities of juvenile crabs are caught in modified pots. Further, the bycatch ratio was significantly reduced for modified compared to the standard entrance pots in this fishery. These results show that such pot modifications have potential to significantly improve the catches in mud crab pot fisheries without increase in capture of bycatch species. However, additional mechanisms for excluding undersized crabs from pot catches should be investigated.ElsevierJournal articleTidsskriftartikkelPeer reviewedMadhu, Anand, Cerbule, Herrmann. Simple pot modification improves catch efficiency and species composition in a tropical estuary mud crab (Scylla serrata) fishery. Estuarine, Coastal and Shelf Science. 2023;288Estuarine, Coastal and Shelf ScienceImpact of ground gear design on catch efficiency in demersal trawl fishery
https://hdl.handle.net/10037/33085
Fakıoğlu, Y.E.; Gökçe, G.; Özbilgin, H.; Cerbule, Kristine; Herrmann, Bent<br />
The choice of ground gear design in demersal trawls can significantly affect both catch composition and efficiency. The preference for a specific design depends on the fishing ground. In the North-Eastern Mediterranean, two types of ground gears, Single Line and Double Line are commonly used. Therefore, this study compared the catch performance for trawls using these ground gears during research trials in the Mersin Bay multi-species demersal trawl fishery. Results showed a significant reduction in catch efficiency for common sole (Solea solea) and lizardfish (Saurida lessepsianus) with more juveniles and target-sized individuals being released by the Double Line trawl compared to the Single Line trawl. Contrary, no difference was obtained for red mullet (Mullus barbatus) between the two gears. The present study demonstrates that ground gear design can affect species and size composition in demersal trawl fisheries. Therefore, ground gear design should be considered in the fisheries regulations as well as for demersal sampling trawl configurations.<br />
2023-02-03T00:00:00ZImpact of ground gear design on catch efficiency in demersal trawl fisheryFakıoğlu, Y.E.Gökçe, G.Özbilgin, H.Cerbule, KristineHerrmann, BentThe choice of ground gear design in demersal trawls can significantly affect both catch composition and efficiency. The preference for a specific design depends on the fishing ground. In the North-Eastern Mediterranean, two types of ground gears, Single Line and Double Line are commonly used. Therefore, this study compared the catch performance for trawls using these ground gears during research trials in the Mersin Bay multi-species demersal trawl fishery. Results showed a significant reduction in catch efficiency for common sole (Solea solea) and lizardfish (Saurida lessepsianus) with more juveniles and target-sized individuals being released by the Double Line trawl compared to the Single Line trawl. Contrary, no difference was obtained for red mullet (Mullus barbatus) between the two gears. The present study demonstrates that ground gear design can affect species and size composition in demersal trawl fisheries. Therefore, ground gear design should be considered in the fisheries regulations as well as for demersal sampling trawl configurations.ElsevierJournal articleTidsskriftartikkelPeer reviewedFakıoğlu, Gökçe, Özbilgin, Cerbule, Herrmann. Impact of ground gear design on catch efficiency in demersal trawl fishery. Regional Studies in Marine Science. 2023;61Regional Studies in Marine Science