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Katsumi Tsukamoto - One of the best experts on this subject based on the ideXlab platform.
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The mysterious feeding ecology of leptocephali: a unique strategy of consuming marine snow materials
Fisheries Science, 2021Co-Authors: Katsumi Tsukamoto, Michael J. MillerAbstract:Leptocephalus Larvae have transparent bodies with tubular intestines that usually lack identifiable food items when they are collected, so mystery has surrounded efforts to determine what they feed on. Artificially spawned and reared first-feeding Larvae were found to be highly selective in what they would eat, but they would consume rotifers and eventually ate specially formulated diets that contained shark egg yolk. Gut content studies on wild-caught leptocephali in the Atlantic and Pacific observed marine snow-associated materials such as discarded appendicularian houses, zooplankton fecal pellets, protists, and amorphous materials, and DNA sequencing indicated that the gut contents contain materials originating from a wide range of microorganisms and food web zooplankton species that were likely consumed in marine snow. Isotopic studies found a low trophic position of leptocephali and inter-taxa and geographic signature differences. Behavioral studies with leptocephali and the characteristics and size-scaling of the teeth are also consistent with feeding on marine snow-related particles. The feeding strategy of leptocephali appears to be based on consuming types of marine snow that contain nutritious and easily assimilated carbohydrates, fatty acids, and other materials that facilitate rapid conversion to glycosaminoglycans and tissues for energy storage and growth.
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Resolving deep-sea pelagic saccopharyngiform eel mysteries: Identification of Neocyema and Monognathidae leptocephali and establishment of a new fish family "Neocyematidae" based on Larvae, adults and mitogenomic gene orders - Fig 3
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi TsukamotoAbstract:Leptocephalus Larvae of saccopharyngiform fishes known until the present study (A–F). A, Eurypharynx (WH404_906) 25.3 mm. B, Saccopharynx (WH342_1580) 40.0 mm. C, Cyema (WH404_82) 26.2 mm. D, “Leptocephalus holti” Type I (KH-11-6_184) 15.4 mm. E, “Leptocephalus holti” Type II (WH342_418) 38.0 mm. F, “Leptocephalus holti” Type III (MSM41_1404) 27.1 mm. Scale bars 5 mm.
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Resolving deep-sea pelagic saccopharyngiform eel mysteries: Identification of Neocyema and Monognathidae leptocephali and establishment of a new fish family "Neocyematidae" based on Larvae, adults and mitogenomic gene orders - Fig 2
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi TsukamotoAbstract:Line-illustrations of Leptocephalus Larvae of meso- and bathypelagic anguilliform families (A–K). A, Cyema (Cyematidae). B, “Leptocephalus holti”. C, Monognathidae (metamorphic stage). D, Unidentified saccopharyngiform. E, Saccopharynx (Saccopharyngidae). F, Eurypharynx (Eurypharyngidae). G, Serrivomer beani (Serrivomeridae). H, Nemichthys curvirostris (Nemichthyidae). I, Avocettina infans (Nemichthyidae). J, Derichthys serpentinus (Derichthyidae). K, Nessorhamphus ingolfianus (Derichthyidae). The dotted line separates the saccopharyngiform Larvae from the Larvae of other meso- and bathy-pelagic eel families. Illustrations A, C, D, F–K are reproduced or modified from Böhlke [1], B is modified from Smith and Miller [24], and E is modified from Castle [84] with permission under a CC BY license, from the Sears Foundation for Marine Research original copyright 1989, illustrator Mary H. Fuges, Yale University, and the American Society of Ichthyologists and Herpetologists, Lawrence, Kansas, respectively.
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NeighborNet network (uncorrected P-distances) of Larvae and adult saccopharyngiforms based on 12S rRNA MiFish DNA sequences.
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi Tsukamoto, Masaki MiyaAbstract:The letters A–M show specimens with DNA sequences of the 12S rRNA MiFish DNA sequences used to construct the network that are matched with photos at the bottom of the figure. General illustrations are shown for adult specimens with no photos (Table 1). Scale bars 5 mm. Although we were able to associate M. jesperseni with its Leptocephalus Larvae (I–J), all remaining monognathid leptocephali Larvae remain to be associated with adult forms.
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Low occurrence rates of ubiquitously present Leptocephalus Larvae in the stomach contents of predatory fish
ICES Journal of Marine Science, 2015Co-Authors: Michael J. Miller, Katsumi Tsukamoto, Jeff Dubosc, Elodie Vourey, Valerie AllainAbstract:Presentaddress: Aquarium des Lagons, 61 PromenadeRoger Laroque, 98800 Noumea, NewCaledonia.Miller, M. J., Dubosc, J., Vourey, E., Tsukamoto, K., and Allain, V. Low occurrence rates of ubiquitously present LeptocephalusLarvae in the stomachcontents of predatoryfish. – ICES Journal of Marine Science, doi: 10.1093/icesjms/fsv034.Received1 December 2014; revised 8 February 2015; accepted10 February 2015.Leptocephali,theLarvaeofeels,growtolargesizesandarewidelydistributedintropicalandsubtropicaloceans.Theirroleinoceanicfoodwebsispoorlyknownbecausetheyarerarelyreportedasfooditemsinfishstomachcontentstudies.Datafrom13yearsofresearchonthetrophicdynamicsofPacificOceanpredatoryfishindicatethatamong8746fishof76species/taxa(33families)thathadbeenfeeding,only16fishof6specieshadremainsof34leptocephaliintheirstomachs.Only0.013%ofthe256308totalpreyitemswereLeptocephalusLarvae,and0.03%ofthetotalpreyitems were juvenile or adult eels (mostly snipe eels: Nemichthyidae). There were 10 fish of 2 species of lancetfish (Alepisaurus spp., n ¼ 152),2rainbowrunners(Elagatisbipinnulata,n ¼ 222),and2yellowfintuna(Thunnusalbacares,n ¼ 3103)thathadleptocephaliintheirstomachcon-tents,but allexceptoneT.albacares(contained15leptocephali)hadeach eaten ≤3leptocephali. Aswallower,Pseudoscopelussp.,andafrigatetuna,Auxisthazard,hadeatensingleleptocephali.Twenty-eightbigeyetuna,Thunnusobesus,hadeaten76juvenile/adultnemichthyidorserri-vomerid eels. A literature survey found that only 15 out of 75 examined publications listed leptocephali in the stomach contents of a total of6 species out of 42300 predatory fish of 40 species. The transparencyof leptocephali and their apparent mimicry of gelatinous zooplanktoncould contribute to lower rates of predation. Their soft bodies likely digest rapidly, so although this study and existing literature indicate thatleptocephali sometimes contribute to predatory fish diets, particularly for fish that do not exclude gelatinous prey types, and fish with lowdigestion rates in their stomachs such as lancetfish, their levels of contribution to fish diets and the impacts of predators on eel recruitmentremain uncertain.Keywords: Alepisaurus, Anguilliformes, leptocephali, Pacific Ocean, predation,predatoravoidance, stomachcontents.
Tadahide Kurokawa - One of the best experts on this subject based on the ideXlab platform.
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Digestive response and rates of growth in pre-Leptocephalus Larvae of the Japanese eel Anguilla japonica reared on artificial diets
Aquaculture, 2003Co-Authors: Benedikte Hedegaard Pedersen, Bernd Ueberschär, Tadahide KurokawaAbstract:As food protein digestion is instrumental for promoting growth, the main protease in young marine fish Larvae, trypsin, was studied in pre-Leptocephalus Larvae of Anguilla japonica. Tryptic enzyme activity was monitored until day 24 and rates of growth until day 36 after hatch in larval A. japonica derived from artificially matured parent fish. Tryptic activity increased with larval age and developmental stage until day 16, after which tryptic levels stabilized. In start-feeding Larvae, tryptic activities increased after ingestion of an artificial diet, but elevated tryptic activities could also be found in Larvae with guts void of prey, possibly due to intestinal retention of trypsin secreted in response to ingestion of a previous meal. Gut retention time for trypsin was estimated to be at least 15 h. The gut evacuation time for the artificial diet depended on the meal size and was in the range of 1-5.5 h. Rates of larval growth in length were ca. 5% day-1 during the yolk-sac stage, declining to ca. 1% day-1 in older Larvae. Vision was highly important for initiation of feeding. Results provide the first quantitative information on aspects of protein digestion in eel Larvae. 2003 Elsevier Science B.V. All rights reserved
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Digestive response and rates of growth in pre-Leptocephalus Larvae of the Japanese eel Anguilla japonica reared on artificial diets
Aquaculture, 2002Co-Authors: Benedikte Hedegaard Pedersen, Bernd Ueberschär, Tadahide KurokawaAbstract:Abstract As food protein digestion is instrumental for promoting growth, the main protease in young marine fish Larvae, trypsin, was studied in pre-Leptocephalus Larvae of Anguilla japonica . Tryptic enzyme activity was monitored until day 24 and rates of growth until day 36 after hatch in larval A. japonica derived from artificially matured parent fish. Tryptic activity increased with larval age and developmental stage until day 16, after which tryptic levels stabilized. In start-feeding Larvae, tryptic activities increased after ingestion of an artificial diet, but elevated tryptic activities could also be found in Larvae with guts void of prey, possibly due to intestinal retention of trypsin secreted in response to ingestion of a previous meal. Gut retention time for trypsin was estimated to be at least 15 h. The gut evacuation time for the artificial diet depended on the meal size and was in the range of 1–5.5 h. Rates of larval growth in length were ca. 5% day −1 during the yolk-sac stage, declining to ca. 1% day −1 in older Larvae. Vision was highly important for initiation of feeding. Results provide the first quantitative information on aspects of protein digestion in eel Larvae.
Michael J. Miller - One of the best experts on this subject based on the ideXlab platform.
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The mysterious feeding ecology of leptocephali: a unique strategy of consuming marine snow materials
Fisheries Science, 2021Co-Authors: Katsumi Tsukamoto, Michael J. MillerAbstract:Leptocephalus Larvae have transparent bodies with tubular intestines that usually lack identifiable food items when they are collected, so mystery has surrounded efforts to determine what they feed on. Artificially spawned and reared first-feeding Larvae were found to be highly selective in what they would eat, but they would consume rotifers and eventually ate specially formulated diets that contained shark egg yolk. Gut content studies on wild-caught leptocephali in the Atlantic and Pacific observed marine snow-associated materials such as discarded appendicularian houses, zooplankton fecal pellets, protists, and amorphous materials, and DNA sequencing indicated that the gut contents contain materials originating from a wide range of microorganisms and food web zooplankton species that were likely consumed in marine snow. Isotopic studies found a low trophic position of leptocephali and inter-taxa and geographic signature differences. Behavioral studies with leptocephali and the characteristics and size-scaling of the teeth are also consistent with feeding on marine snow-related particles. The feeding strategy of leptocephali appears to be based on consuming types of marine snow that contain nutritious and easily assimilated carbohydrates, fatty acids, and other materials that facilitate rapid conversion to glycosaminoglycans and tissues for energy storage and growth.
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Resolving deep-sea pelagic saccopharyngiform eel mysteries: Identification of Neocyema and Monognathidae leptocephali and establishment of a new fish family "Neocyematidae" based on Larvae, adults and mitogenomic gene orders - Fig 3
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi TsukamotoAbstract:Leptocephalus Larvae of saccopharyngiform fishes known until the present study (A–F). A, Eurypharynx (WH404_906) 25.3 mm. B, Saccopharynx (WH342_1580) 40.0 mm. C, Cyema (WH404_82) 26.2 mm. D, “Leptocephalus holti” Type I (KH-11-6_184) 15.4 mm. E, “Leptocephalus holti” Type II (WH342_418) 38.0 mm. F, “Leptocephalus holti” Type III (MSM41_1404) 27.1 mm. Scale bars 5 mm.
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Resolving deep-sea pelagic saccopharyngiform eel mysteries: Identification of Neocyema and Monognathidae leptocephali and establishment of a new fish family "Neocyematidae" based on Larvae, adults and mitogenomic gene orders - Fig 2
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi TsukamotoAbstract:Line-illustrations of Leptocephalus Larvae of meso- and bathypelagic anguilliform families (A–K). A, Cyema (Cyematidae). B, “Leptocephalus holti”. C, Monognathidae (metamorphic stage). D, Unidentified saccopharyngiform. E, Saccopharynx (Saccopharyngidae). F, Eurypharynx (Eurypharyngidae). G, Serrivomer beani (Serrivomeridae). H, Nemichthys curvirostris (Nemichthyidae). I, Avocettina infans (Nemichthyidae). J, Derichthys serpentinus (Derichthyidae). K, Nessorhamphus ingolfianus (Derichthyidae). The dotted line separates the saccopharyngiform Larvae from the Larvae of other meso- and bathy-pelagic eel families. Illustrations A, C, D, F–K are reproduced or modified from Böhlke [1], B is modified from Smith and Miller [24], and E is modified from Castle [84] with permission under a CC BY license, from the Sears Foundation for Marine Research original copyright 1989, illustrator Mary H. Fuges, Yale University, and the American Society of Ichthyologists and Herpetologists, Lawrence, Kansas, respectively.
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NeighborNet network (uncorrected P-distances) of Larvae and adult saccopharyngiforms based on 12S rRNA MiFish DNA sequences.
2018Co-Authors: Jan Y. Poulsen, Michael J. Miller, Tetsuya Sado, Reinhold Hanel, Katsumi Tsukamoto, Masaki MiyaAbstract:The letters A–M show specimens with DNA sequences of the 12S rRNA MiFish DNA sequences used to construct the network that are matched with photos at the bottom of the figure. General illustrations are shown for adult specimens with no photos (Table 1). Scale bars 5 mm. Although we were able to associate M. jesperseni with its Leptocephalus Larvae (I–J), all remaining monognathid leptocephali Larvae remain to be associated with adult forms.
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reproductive ecology and biodiversity of freshwater eels around sulawesi island indonesia
Zoological Studies, 2018Co-Authors: Jun Aoyama, Michael J. Miller, Sam Wouthuyzen, Hagi Yulia Sugeha, Mari Kuroki, Shun Watanabe, Augy Syahailatua, Fadly Y Tantu, Seishi Hagihara, Tsuguo OtakeAbstract:Jun Aoyama, Sam Wouthuyzen, Michael J. Miller, Hagi Y. Sugeha, Mari Kuroki, Shun Watanabe, Augy Syahailatua, Fadly Y. Tantu, Seishi Hagihara, Triyanto, Tsuguo Otake, and Katsumi Tsukamoto (2018) Sulawesi Island of north-central Indonesia is located in a region where at least 6 species of tropical anguillid eels are present, but the reproductive ecology and biodiversity of these eels in each area of the Indonesian archipelago remains poorly understood. Some information about these species was obtained from collections of their Leptocephalus Larvae made during several times of the year and from year-round collections of their recruitment-stage glass eels at a few locations. A sampling survey of anguillid leptocephali was conducted in March 2010 in both the Celebes Sea and Tomini Bay of Sulawesi Island to learn about the biodiversity and reproductive ecology of the eels in the region. Twenty-eight anguillid leptocephali were collected at 13 different stations, with genetic identification indicating that 3 species of eels had spawned in the two areas. Larvae were more abundant in the Celebes Sea (N = 21; 16.0-52.1 mm TL) than in Tomini Bay (N = 7; 9.6-54.8 mm). The abundant 16-21 mm size-class of Anguilla bornensis in the Celebes Sea indicated that species had recently spawned there, and spawning had also occurred in Tomini Bay by A. celebesensis (17.4 mm). These data and previous life history information suggest that A. celebesensis may have two spawning seasons in the Celebes Sea, but only one main spawning season in Tomini Bay. Anguilla borneensis may spawn at several times of the year in the Celebes Sea. Anguilla marmorata and A. biocolor pacifica spawn outside the Indonesian Seas, with A. marmorata recruiting in large numbers in the Sulawesi Island region during much of the year. Other spawning locations of A. celebesensis and A. interioris likely exist in Indonesian waters. Therefore, further research is needed to understand the reproductive ecologies and biodiversity of the tropical anguillid eels in each region of Indonesia in relation to geographic and climatic factors.
Dominique Adriaens - One of the best experts on this subject based on the ideXlab platform.
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musculoskeletal anatomy and feeding performance of pre feeding engyodontic Larvae of the european eel anguilla anguilla
Journal of Anatomy, 2015Co-Authors: Mathias Bouilliart, Peter Lauesen, Jonna Tomkiewicz, Barbara De Kegel, Dominique AdriaensAbstract:: Being part of the elopomorph group of fishes, Anguillidae species show a Leptocephalus larval stage. However, due to largely unknown spawning locations and habitats of their earliest life stages, as well as their transparency, these Anguilla Larvae are rarely encountered in nature. Therefore, information regarding the early life history of these Larvae, including their exogenous feeding strategy and feeding performance, is rather scarce. To better understand the structural basis and functional performance of larval feeding in captivity, the functional morphology of the cranial musculoskeletal system in pre- and first-feeding engyodontic leptocephali of the European eel (Anguilla anguilla) was studied. A 3D reconstruction of the feeding apparatus (head of the leptocephali < 1 mm) was used to visualize and describe the musculoskeletal changes throughout these stages. To analyze the ontogenetic changes in the functionality of the feeding apparatus towards the active feeding phase, 3D data of joints, levers and muscles derived from the reconstructions were used to estimate bite and joint reaction forces (JRFs). Observing a maximum estimated bite force of about 65 μN (and corresponding JRFs of 260 μN), it can be hypothesized that Leptocephalus Larvae are functionally constrained to feed only on soft food particles. Additionally, potential prey items are size delimited, based on the theoretically estimated average gape of these Larvae of about 100 μm. This hypothesis appears to be in line with recent observations of a diet consisting of small and/or gelatinous prey items (Hydrozoa, Thaliacea, Ctenophora, Polycystenia) found in the guts of euryodontic Leptocephalus Larvae.
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Between the jaws of the Leptocephalus larva: biomechanically approaching a rarely observed organism
2014Co-Authors: Mathias Bouilliart, Peter Lauesen, Jonna Tomkiewicz, Barbara De Kegel, Akihiro Okamura, Dominique AdriaensAbstract:Being part of the Elopomorph group of fishes, Anguillidae species have a Leptocephalus larval stage. Unfortunately, due to (mostly) unknown deep-water marine birthplaces, a catadromous lifestyle, and a transparent body morphology, these Anguilla Larvae are rarely encountered in nature. Therefore, information regarding the early development of these Larvae, including the exogenous feeding strategy and feeding performance, is rather scarce. To get some insight into these early ontogenetic changes and their influence on the functionality of the developing feeding apparatus, an ontogenetic series is put together from two artificially bred Anguillids. Throughout this series, graphical three-dimensional reconstructions (based on histological sections) of the musculoskeletal system of European (Anguilla anguilla) and Japanese eel (Anguilla japonica) Larvae provide detailed descriptions of the changing feeding apparatus. Subsequently, theoretical bite forces are calculated for every reconstructed phase, using 3D data of joints, levers, and muscles derived from these reconstructions. Although the expected increase in bite force is observed with progressing age of the Larvae, the obtained forces remain rather small (several µN). As a result, Leptocephalus Larvae are hypothesized to be anatomically constrained to feed only on soft and/or small food particles, which is in line with the current observations of small and/or gelatinous prey items (Hydrozoa, Thaliacea, Ctenophora, Polycystenia) in the guts of these Larvae.
Benedikte Hedegaard Pedersen - One of the best experts on this subject based on the ideXlab platform.
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Digestive response and rates of growth in pre-Leptocephalus Larvae of the Japanese eel Anguilla japonica reared on artificial diets
Aquaculture, 2003Co-Authors: Benedikte Hedegaard Pedersen, Bernd Ueberschär, Tadahide KurokawaAbstract:As food protein digestion is instrumental for promoting growth, the main protease in young marine fish Larvae, trypsin, was studied in pre-Leptocephalus Larvae of Anguilla japonica. Tryptic enzyme activity was monitored until day 24 and rates of growth until day 36 after hatch in larval A. japonica derived from artificially matured parent fish. Tryptic activity increased with larval age and developmental stage until day 16, after which tryptic levels stabilized. In start-feeding Larvae, tryptic activities increased after ingestion of an artificial diet, but elevated tryptic activities could also be found in Larvae with guts void of prey, possibly due to intestinal retention of trypsin secreted in response to ingestion of a previous meal. Gut retention time for trypsin was estimated to be at least 15 h. The gut evacuation time for the artificial diet depended on the meal size and was in the range of 1-5.5 h. Rates of larval growth in length were ca. 5% day-1 during the yolk-sac stage, declining to ca. 1% day-1 in older Larvae. Vision was highly important for initiation of feeding. Results provide the first quantitative information on aspects of protein digestion in eel Larvae. 2003 Elsevier Science B.V. All rights reserved
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Digestive response and rates of growth in pre-Leptocephalus Larvae of the Japanese eel Anguilla japonica reared on artificial diets
Aquaculture, 2002Co-Authors: Benedikte Hedegaard Pedersen, Bernd Ueberschär, Tadahide KurokawaAbstract:Abstract As food protein digestion is instrumental for promoting growth, the main protease in young marine fish Larvae, trypsin, was studied in pre-Leptocephalus Larvae of Anguilla japonica . Tryptic enzyme activity was monitored until day 24 and rates of growth until day 36 after hatch in larval A. japonica derived from artificially matured parent fish. Tryptic activity increased with larval age and developmental stage until day 16, after which tryptic levels stabilized. In start-feeding Larvae, tryptic activities increased after ingestion of an artificial diet, but elevated tryptic activities could also be found in Larvae with guts void of prey, possibly due to intestinal retention of trypsin secreted in response to ingestion of a previous meal. Gut retention time for trypsin was estimated to be at least 15 h. The gut evacuation time for the artificial diet depended on the meal size and was in the range of 1–5.5 h. Rates of larval growth in length were ca. 5% day −1 during the yolk-sac stage, declining to ca. 1% day −1 in older Larvae. Vision was highly important for initiation of feeding. Results provide the first quantitative information on aspects of protein digestion in eel Larvae.