A kinematic comparison of forward and backward swimming in the eel anguilla anguilla

1999 ◽  
Vol 202 (11) ◽  
pp. 1511-1521 ◽  
Author(s):  
K. D'Août ◽  
P. Aerts
Keyword(s):  
Anguilla Anguilla ◽  
Total Body Length ◽  
The Body ◽  
European Eel ◽  
Muscle Strain ◽  
Cycle Frequency ◽  
Amplitude Profile ◽  
Total Body ◽  
Tail Tip ◽  
Undulatory Swimming

In addition to forward undulatory swimming, eels (and some other elongated swimmers) can swim backwards in a similar way. We compared the kinematics (wave speed, cycle frequency, amplitude, local bending and estimated muscle strain) of forward and backward swimming in the European eel Anguilla anguilla. Both swimming modes are characterised by a wave of undulation that travels over the body in the direction opposite to that of swimming. We observe two major kinematic differences. First, the slope of wave frequency against swimming speed is significantly higher for backward than for forward swimming. Second, the amplitude profile along the body of the propulsive wave differs greatly. During forward swimming, the yaw at the head is minimal and the amplitude of the propulsive wave increases to approximately 15 % (left-to-right) of total body length towards the tail tip. During backward swimming, the amplitude profile is rather uniform along the body (with values similar to the tail-tip amplitude during forward swimming), resulting in considerable lateral head oscillation. Strikingly, the head remains approximately parallel to the swimming direction, which presumably enhances visual and acoustico-lateral perception. Furthermore, muscle strain is much higher in the rostral part of the body during backward swimming than during forward swimming. Values for stride length and propeller efficiency suggest that backward undulatory swimming is mechanically less efficient than forward swimming. We suggest that the typical anguilliform body shape is an important feature that allows these animals to swim backwards using an undulatory mechanism that resembles the forward undulatory swimming mechanism. Most other fishes, if able to swim backwards at all, do so using fin oscillations or undulations.

Kinematics and efficiency of steady swimming in adult axolotls (Ambystoma mexicanum)

1997 ◽  
Vol 200 (13) ◽  
pp. 1863-1871 ◽  
Author(s):  
K D'Août ◽  
P Aerts
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Natural Habitat ◽  
Total Body Length ◽  
Ambystoma Mexicanum ◽  
The Body ◽  
Entire Body ◽  
Amplitude Profile ◽  
Wide Range ◽  
Tail Tip

The kinematics of steady swimming at a wide range of velocities was analysed using high-speed video recordings (500 frames s-1) of eight individuals of Ambystoma mexicanum swimming through a tunnel containing stationary water. Animals in the observed size range (0.135­0.238 m total body length) prefer to swim at similar absolute speeds, irrespective of their body size. The swimming mechanism is of the anguilliform type. The measured kinematic variables ­ the speed, length, frequency and amplitude (along the entire body) of the propulsive wave ­ are more similar to those of anguilliform swimming fish than to those of tadpoles, in spite of common morphological features with the latter, such as limbs, external gills and a tapering tail. The swimming speed for a given animal size correlates linearly with the tailbeat frequency (r2=0.71), whereas the wavelength and tail-tip amplitude do not correlate with this variable. The shape of the amplitude profile along the body, however, is very variable between the different swimming bouts, even at similar speeds. It is suggested that, for a given frequency, the amplitude profile along the body is adjusted in a variable way to yield the resulting swimming speed rather than maintaining a fixed-amplitude profile. The swimming efficiency was estimated by calculating two kinematic variables (the stride length and the propeller efficiency) and by applying two hydrodynamic theories, the elongated-body theory and an extension of this theory accounting for the slope at the tail tip. The latter theory was found to be the most appropriate for the axolotl's swimming mode and yields a hydromechanical efficiency of 0.75±0.04 (mean ± s.d.), indicating that Ambystoma mexicanum swims less efficiently than do anuran tadpoles and most fishes. This can be understood given its natural habitat in vegetation at the bottom of lakes, which would favour manoeuvrability and fast escape.

Morphological and molecular characterisation of Pratylenchus rwandae n. sp. (Tylenchida: Pratylenchidae) associated with maize in Rwanda

Nematology ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 781-794 ◽  
Author(s):  
Phougeishangbam Rolish Singh ◽  
Alliance Nyiragatare ◽  
Toon Janssen ◽  
Marjolein Couvreur ◽  
Wilfrida Decraemer ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Total Body Length ◽  
Morphological Characters ◽  
Variable Number ◽  
The Body ◽  
Lateral Field ◽  
Lateral Lines ◽  
Unidentified Species ◽  
Total Body ◽  
Tail Tip

Summary Pratylenchus rwandae n. sp., a root-lesion nematode associated with maize (Zea mays) from Rwanda, is described. This new species is characterised by females of medium to large size (469-600 μm) having an offset lip region with three annuli, stylet of 13-14.6 μm long with prominent rounded or anteriorly concave knobs, short to long pharyngeal gland overlap of 10.9-34.7 μm long, variable number of lateral lines (4-14) in different regions of the body, lateral field consisting of smooth bands, oval to slightly rounded spermatheca, vulva located at 75-80% of the total body length, post-vulval uterine sac (PUS) 20.3-26.5 μm long, tail subcylindrical to conoid with variation in tail tip shape from rounded to truncate or indented with generally smooth tip, and male unknown. The results of the phylogenetic analyses based on sequences of the D2-D3 expansion regions of 28S, partial 18S and ITS of rDNA and COI of mitochondrial DNA indicate that P. rwandae n. sp. is a species within the Penetrans group and appears as a sister species to a group comprising P. convallariae, P. dunensis, P. fallax, P. oleae, P. penetrans, P. pinguicaudatus, and three other unidentified species. A comparison of important morphological characters of the closely related Pratylenchus spp. is provided.

scholarly journals Relationships of Otolith Dimension with Body Length of European Eel Anguilla anguilla (Linnaeus, 1758) from Adriatic catchment of Montenegro

2018 ◽  
Vol 59 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Tamara Kanjuh ◽  
Danilo Mrdak
Keyword(s):  
Linear Function ◽  
Body Length ◽  
Somatic Growth ◽  
Anguilla Anguilla ◽  
Body Growth ◽  
The Body ◽  
European Eel ◽  
Fish Size ◽  
Sagittal Otolith ◽  
The Relationship

This study examined the relationship between the sagittal otolith morphometric variables (length, height and weight) and body growth of the European eel. Eels that were studied ranged in total length from 11.2 to 79.5 cm. The relationships between the sagittal otolith variables and fish somatic growth were described with a non-linear function. The resulting coefficients of determination \((r^2)\) ranged from 0.782 to 0.914. The variable most strongly related to fish size was found to be the sagittal otolith length (OL) with 91.4 % of the variability. The results of this study provide the first comprehensive data regarding the relationship between the sagittal otolith morphometric variables with the body length of Anguilla anguilla.

Thelastoma gueyei sp. n. (Nematoda: Thelastomatidae) from the Senegal diplopod Archispirostreptus tumuliporus (Diplopoda: Spirostreptidae)

Nematology ◽  
2006 ◽  
Vol 8 (5) ◽  
pp. 739-747 ◽  
Author(s):  
Božena Koubková ◽  
Vlastimil Baruš ◽  
Iveta Matějusová ◽  
Iveta Hodová ◽  
Petr Koubek
Keyword(s):  
Ribosomal Rna ◽  
Morphological Characteristics ◽  
Total Body Length ◽  
Small Subunit ◽  
Species Group ◽  
The Body ◽  
Pharyngeal Bulb ◽  
Genital Cone ◽  
Tail Spike ◽  
Total Body

Abstract Thelastoma gueyei sp. n., a nematode belonging to the long-tailed species group of the genusThelastoma, is described from the diplopodArchispirostreptus tumuliporus (Spirostreptidae) collected in Niokolo Koba National Park (Senegal, West Africa).Thelastoma gueyei sp. n. is morphologically most similar toT. gipetiti. Females are characterised by: the vulva being situated in the posterior half of the body and near to the anus (V′ = 75-86) with the anterior vulval lip developed into a prominent flap; excretory pore located at the level of the anterior end of the pharyngeal bulb; b′ = 28-38 and tail, expressed as a proportion of L′, = 1.7-2.7. Males have narrow cuticular alae extending from about the middle of the pharynx to the level of the anteriormost pair of copulatory papillae; four pairs of copulatory papillae, two large, subventral, pairs being located adcloacally on the genital cone, a third, much smaller pair on the posterior margin of the genital cone and the last pair being situated at the mid-point of the tail spike; and a tail occupying 10.8-13.2% of the total body length. The distal tip of the spicule is drop-shaped. Morphological characteristics were studied using scanning electron microscopy and a comparison of the long-tailed group of thelastomatids is provided. Nucleic acid sequence of the small subunit ribosomal RNA gene was obtained for purposes of DNA barcoding.

scholarly journals PENGUKURAN PANJANG TUBUH CACING NIPAH PENDEK Namalycastis abiuma (POLYCHAETA: NEREDIDAE) DARI PERAIRAN MANGROVE SUNGAI KAPUAS KALIMANTAN BARAT

2018 ◽  
Vol 11 (2) ◽  
pp. 183-189
Author(s):  
Junardi Junardi
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Body Length ◽  
Anterior Segment ◽  
Total Body Length ◽  
The Body ◽  
Female Body Size ◽  
Alternative Approach ◽  
Total Body ◽  
The Relationship

AbstrakCacing Nipah Pendek Namalycastis abiuma memiliki tubuh yang elastis dan mudah putus sehingga diperlukan pendekatan morfometri tubuh lain untuk menentukan panjang tubuh sesungguhnya. Tujuan penelitian ini untuk menentukan panjang tubuh total cacing nipah pendek dengan menggunakan bobot tubuh, jumlah total segmen berseta, panjang tiga segmen anterior pertama (L3) dan lebar segmen berseta atau setiger ke-10 (S-10). Spesimen yang digunakan dipilih hanya individu yang lengkap dan utuh. Pengukuran dilakukan dibawah mikroskop dengan lensa okular yang dilengkapi dengan mikrometer. Data dianalisis dengan analisis korelasi. Cacing yang digunakan sebanyak 258 individu yang terdiri atas 190 immature, 54 submature dan 14 mature dengan ukuran panjang tubuh rata-rata berturut-turut 108,62±34,80 mm, 172,27±42,78 mm dan 123,14±57,40 mm. Cacing betina ditemukan memiliki ukuran tubuh lebih besar dari jantan. Panjang tubuh N. abiuma dapat diduga dengan bobot tubuh, panjang L3 dan lebar S-10 dengan nilai koefisien korelasi (r) berturut-turut 0,82, 0,73 dan 0,78. Pendekatan morfometri dapat digunakan untuk menentukan ukuran tubuh N. abiuma.Abstract The short nypa palm worm Namalycastis abiuma has an elastic and fragile body. Therefore, an alternative approach of morphometrical techniques is needed to determine the total body length. This research aimed to estimate the total body length of the short nypa palm worm based on body weight, the total number of segments, the length of the first three anterior segment (L3) and the tenth setiger width (S10). Body measurement was done using stereomicroscope fitted with the micrometer. Correlation analysis was done to describe the relationship between the length of L3 and the width of S10. A total of 258 complete and whole specimens consisted of 190 immature, 54 submature, and 14 mature individuals. The average body length of immature individuals was 108.62±34.80 mm, 172.27±42.78 mm for sub mature individuals, and 123.14±57.40 mm for mature individuals. Based on sexual dimorphism, the female body size is larger than male. The body length of N. abiuma can be estimated by body weight, the length of L3, and the  width of S10, with  correlation coefficient (r) of 0.82, 0.73 and 0.78, respectively. Morphometry approach can be used to determine the body size of N. abiuma. 

scholarly journals Length-weight relationship of European catfish (Silurus glanis L.) fry reared at different stocking densities under controlled conditions

2021 ◽  
pp. 47-51
Author(s):  
V. Krasteva ◽  
M. Yankova
Keyword(s):  
Body Length ◽  
Stocking Density ◽  
Total Body Length ◽  
The Body ◽  
Small Fish ◽  
Silurus Glanis ◽  
Group A ◽  
European Catfish ◽  
Total Body ◽  
Group B

Abstract. The present paper investigates the body length and weight, and the size-weight variations of one-month-old European catfish reared at 4 variants of stocking density: Variant 1 – 5 spec/l; Variant 2 – 10 spec/l; Variant 3 – 15 spec/l and Variant 4 – 28 spec/l. The experiment is carried out at the Institute of Fisheries and Aquaculture, Plovdiv for a period of 16 days, using a production system consisting of tubs with continuous water flow (0.7 l/min). At the end of the experiment, the fish from each variant are sorted in three size-weight groups: A – large, B – medium and C – small. The number of fish in each group is established. From the group of the medium- and small-sized fish, 150 speciments are measured, while from the group of the large specimens, which are the smallest in number, all specimens are measured for the biometric parameters body weight (BW, g) and total body length (TL, cm). The results from the study show small variations in the length and weight of the fish reared at the lowest stocking density (Variant 1). As the density increase, the size-weight differences between the specimens from Group A also increased, while of those from Group B they decrease. The number of the medium-sized fish decrease (p≤0.001) while the number of large specimens (p≤0.01) and small fish increase (p≤0.001).

Swimming in needlefish (Belonidae): anguilliform locomotion with fins

2002 ◽  
Vol 205 (18) ◽  
pp. 2875-2884 ◽  
Author(s):  
James C. Liao
Keyword(s):  
Surface Waters ◽  
High Speed ◽  
Total Body Length ◽  
The Body ◽  
Pectoral Fins ◽  
Half Wavelength ◽  
Total Body ◽  
Length Analysis ◽  
Median Fins ◽  
Tail Beat

SUMMARYThe Atlantic needlefish (Strongylura marina) is a unique anguilliform swimmer in that it possesses prominent fins, lives in coastal surface-waters, and can propel itself across the surface of the water to escape predators. In a laboratory flow tank, steadily swimming needlefish perform a speed-dependent suite of behaviors while maintaining at least a half wavelength of undulation on the body at all times. To investigate the effects of discrete fins on anguilliform swimming, I used high-speed video to record body and fin kinematics at swimming speeds ranging from 0.25 to 2.0 Ls-1 (where L is the total body length). Analysis of axial kinematics indicates that needlefish are less efficient anguilliform swimmers than eels, indicated by their lower slip values. Body amplitudes increase with swimming speed, but unlike most fishes, tail-beat amplitude increases linearly and does not plateau at maximal swimming speeds. At 2.0 Ls-1, the propulsive wave shortens and decelerates as it travels posteriorly, owing to the prominence of the median fins in the caudal region of the body. Analyses of fin kinematics show that at 1.0 Ls-1 the dorsal and anal fins are slightly less than 180° out of phase with the body and approximately 225° out of phase with the caudal fin. Needlefish exhibit two gait transitions using their pectoral fins. At 0.25 L s-1, the pectoral fins oscillate but do not produce thrust, at 1.0 L s-1 they are held abducted from the body,forming a positive dihedral that may reduce rolling moments, and above 2.0 L s-1 they remain completely adducted.

scholarly journals A new xandarellid euarthropod from the Cambrian Chengjiang biota, Yunnan Province, China

2018 ◽  
Vol 156 (08) ◽  
pp. 1375-1384 ◽  
Author(s):  
Xianguang Hou ◽  
Mark Williams ◽  
Robert Sansom ◽  
Derek J. Siveter ◽  
David J. Siveter ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Body Length ◽  
Yunnan Province ◽  
Total Body Length ◽  
The Body ◽  
Mode Of Life ◽  
Chengjiang Biota ◽  
Total Body

AbstractThe euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjiang biota, Cambrian Series 2, Stage 3, of Yunnan Province, China. Phylogenetic analysis recovers a xandarellid affinity for L. deletres, representing only the fifth described species of this clade. L. deletres possesses a head shield that is about one-fifth of the total body length and a trunk with 30 tergites, the reduced anterior-most tergite and terminal three tergites lacking pleural elongations. Anteriorly situated notches in the head shield are associated with stalked eyes, in contrast to the more posterior, enclosed eye slits present in Xandarella. Posterior to the antennae there are at least 11 pairs of biramous appendages preserved, including three pairs in the head. The morphology of the midline gut of L. deletres, in which lateral, unbranched diverticula are wider towards the front of the body, is a characteristic also found in various trilobites. The dorsoventrally flattened exoskeleton suggests a benthic or nektobenthic mode of life for L. deletres, as for other trilobitomorphs, and it likely used its well-developed anteriorly positioned eyes for searching out food, either to scavenge or to find prey.

Two new species of philometrid nematodes (Nematoda: Philometridae) in Epinephelus coioides (Hamilton, 1822) from the South Bali Sea, Indonesia

Zootaxa ◽  
2013 ◽  
Vol 3609 (1) ◽  
pp. 49-59 ◽  
Author(s):  
KARTIKA DEWI ◽  
HARRY W. PALM
Keyword(s):  
New Species ◽  
Body Length ◽  
Total Body Length ◽  
Middle Part ◽  
The Body ◽  
Epinephelus Coioides ◽  
The South ◽  
Fish Family ◽  
Two New Species ◽  
Total Body

Based on light and scanning electron microscopy, two new species of philometrid nematodes, Spirophilometra endangae sp. nov. and Philometra epinepheli sp. nov. (Nematoda: Dracunculoidea: Philometridae) are described from Epinephelus coioides (Hamilton, 1822) (Perciformes: Serranidae) from the South Bali Sea, Indonesia. Spirophilometra endangae sp. nov. was isolated from the fins of E. coioides. The new species can be distinguished from the most closely related S. eichleri Parukhin, 1971 by a larger total body length and the site of infection in the host. The new species differs from S. centropomi (Caballero, 1974) also in the larger body size of the gravid females and the site of infection in the host. S. en-dangae sp. nov. differs from S. pacifica (Moravec, Santana-Pineros, Gonzales-Solis & Torres-Huerta, 2007) in the struc-ture and arrangement of the spines on the middle part of the body, the infection site of the worm, the type host and the zoogeographical host distribution. Philometra epinepheli sp. nov. differs from all other Philometra spp. congeners so far recorded from Ephinepelus groupers in the total body length and the site of infection. This is the first opercula-infecting species of Philometra described from the fish family Serranidae.

scholarly journals Pre-release processes influencing short-term mortality of glass eels in the French eel (Anguilla anguilla, Linnaeus 1758) stocking programme

2015 ◽  
Vol 73 (1) ◽  
pp. 150-157 ◽  
Author(s):  
Q. Josset ◽  
T. Trancart ◽  
V. Mazel ◽  
F. Charrier ◽  
L. Frotté ◽  
...  
Keyword(s):  
Body Condition ◽  
Anguilla Anguilla ◽  
Management Plan ◽  
The Body ◽  
European Eel ◽  
The European Union ◽  
Short Term ◽  
Good Body Condition ◽  
Short Term Mortality ◽  
Glass Eels

Abstract The decline in the European eel has led the European Union to require that its Member States establish an Eel Management Plan, which includes a set of measures to help preserve and restore the wild eel populations. Stocking has been conducted in France since 2011 as part of this Management Plan. This stocking programme is based on a protocol designed by the French National Museum of Natural History and includes an assessment of the short-term (15 d after release) mortality and three recapture surveys at 6, 12, and 36 months after release. The present study aims to assess the different processes influencing the short-term mortality to provide recommendations to reduce mortality and increase the efficiency of the releases. A linear model was built to examine the different variables selected modelling. The resulting model explained 56.4% of the total deviance; the main factor in terms of explained deviance was the operation (31.2%), which actually includes a number of handling parameters. The other factors influencing the short-term mortality were the release year, the fishmonger that provided the glass eels, the duration of stalling (period of captivity) before release, the body condition, the marking, and the type of mortality test. It appears that some of these variables could be adjusted to reduce the short-term mortality. For instance, selecting the most suitable release sites to stock or selecting glass eels with good body condition, adjusting the duration of stalling, or limiting the marking should help reduce short-term mortality.

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