Développement morphologique et croissance des juvéniles de l'Owenia fusiformis Delle Chiaje (Polychaeta, Oweniidae)

1992 ◽  
Vol 70 (9) ◽  
pp. 1701-1711 ◽  
Author(s):  
Éric Thiébaut ◽  
Jean-Claude Dauvin
Keyword(s):  
Size Distribution ◽  
Larval Stage ◽  
Individual Growth ◽  
Morphological Development ◽  
English Channel ◽  
Demographic Structure ◽  
Differential Growth ◽  
Total Length ◽  
Branchial Crown ◽  
Over Time

The morphological development of the branchial crown and uncinigerous tori, growth, and demographic structure were observed in juveniles of Owenia fusiformis Delle Chiaje, 1841 from the Bay of Seine (eastern English Channel). Growth becomes significant only after one and a half months of benthic life; individual growth is highly variable and results in a progressive widening of the size distribution of the population over time. From six initial branches present at the post-larval stage, seven stages of branchial development can be distinguished. The branchial crown develops by successive dichotomous divisions and growth of the new branches. The number of dichotomous divisions (D) increases with total length (LT) and age (A): D = 1.718 ln(LT) − 0.291; D = 0.987 ln(A) − 1.471. The number of uncinigerous tori (T) increases with total length (LT) and age (A): T = 4.272 ln(LT) + 7.272; T = 4.477 ln(A) − 2.479. The acquisition of fully grown characters after metamorphosis was progressive and depended more on total length of the juvenile than on age. At any given age, there was an important variability in investigated characters because of differential growth of juveniles. Ecological consequences resulting from interactions between morphological development and growth with respect to recruitment are discussed.

Occurrence of ocean sunfish, Mola mola near fronts in the western English Channel

2002 ◽  
Vol 82 (5) ◽  
pp. 927-928 ◽  
Author(s):  
D.W. Sims ◽  
E.J. Southall
Keyword(s):  
Water Masses ◽  
English Channel ◽  
Ocean Sunfish ◽  
Total Length ◽  
Mola Mola ◽  
Mixed Water ◽  
Surface Occurrence

Surface occurrence of ocean sunfish (Mola mola) was recorded during summer (May–September) in the western English Channel off Plymouth over a six-year period between 1995 and 2001. Fifteen individuals of between 0.5–0.7 m estimated total length were sighted during 1651 hours of observation. Nearly all sightings (93%) occurred in June and July in water between 13 and 17°C. Sunfish were mostly associated with frontal and stratified water masses (86%) rather than in cooler, mixed water.

scholarly journals Early development and allometric growth in Nannacara anomala Regan, 1905 (Perciformes: Cichlidae) under laboratory conditions

2014 ◽  
Vol 12 (3) ◽  
pp. 659-665 ◽  
Author(s):  
Krzysztof Kupren ◽  
Maja Prusińska ◽  
Daniel Żarski ◽  
Sławomir Krejszeff ◽  
Dariusz Kucharczyk
Keyword(s):  
Early Development ◽  
Morphological Development ◽  
Allometric Growth ◽  
Laboratory Conditions ◽  
Total Length ◽  
Larvae And Juveniles ◽  
The Mean ◽  
Accelerated Growth

Morphological development and allometric growth of laboratory reared Nannacara anomala were studied from hatching to the loss of larval characters and beginning of squamation (18 days post-hatching) at 26°C. The mean total length (TL) of larvae and juveniles increased from 3.74 mm at hatching to 9.60 mm at metamorphosis. Morphogenesis and differentiation were most intense during the first week of development. During this period (TL interval = 3.74 - 4.84 mm) there was an evident priority to enhance the feeding and swimming capabilities by promoting accelerated growth in the head and tail regions. Following this period, there was a major decrease in growth coefficients, indicating a change in growth priorities. Observations on the early development of Nannacara anomala confirmed the basic uniformity development of a substrate brooding cichlid.

Linking temporal changes in the demographic structure and individual growth to the decline in the population of a tropical fish

2015 ◽  
Vol 165 ◽  
pp. 166-175 ◽  
Author(s):  
Charlotte Sirot ◽  
Audrey M. Darnaude ◽  
François Guilhaumon ◽  
Julia Ramos-Miranda ◽  
Domingo Flores-Hernandez ◽  
...  
Keyword(s):  
Temporal Changes ◽  
Tropical Fish ◽  
Individual Growth ◽  
Demographic Structure

scholarly journals The NCAR–FAA Snow Machine: An Artificial Snow-Generation System

2018 ◽  
Vol 35 (11) ◽  
pp. 2159-2168
Author(s):  
Scott D. Landolt ◽  
Roy M. Rasmussen ◽  
Alan J. Hills ◽  
Warren Underwood ◽  
Charles A. Knight ◽  
...  
Keyword(s):  
Mass Balance ◽  
Size Distribution ◽  
Liquid Water ◽  
Generation System ◽  
Fall Velocity ◽  
Atmospheric Research ◽  
Controlled Conditions ◽  
Precipitation Gauge ◽  
Cold Chamber ◽  
Over Time

AbstractThe National Center for Atmospheric Research (NCAR) developed an artificial snow-generation system designed to operate in a laboratory cold chamber for testing aircraft anti-icing fluids under controlled conditions. Flakes of ice are produced by shaving an ice cylinder with a rotating carbide bit; the resulting artificial snow is dispersed by turbulent airflows and falls approximately 2.5 m to the bottom of the device. The resulting fine ice shavings mimic snow in size, distribution, fall velocity, density, and liquid water equivalent (LWE) snowfall rate. The LWE snowfall rate can be controlled using either a mass balance or a precipitation gauge, which measures the snowfall accumulation over time, from which the computer derives the LWE rate. LWE snowfall rates are calculated every 6 s, and the rate the ice cylinder is fed into the carbide bit is continually adjusted to ensure that the LWE snowfall rate matches a user-selected value. The system has been used to generate LWE snowfall rates ranging from 0 to 10 mm h−1 at temperatures from −2 to −30°C and densities of approximately 0.1–0.5 g cm−3. Comparisons of the snow-machine fluid tests with the outdoor fluid tests have shown that the snow machine can mimic natural outdoor rates under a broad range of conditions.

scholarly journals Continuities and discontinuities of Russian urban housing: The Soviet housing experiment in historical long-term perspective

Urban Studies ◽  
2019 ◽  
Vol 57 (8) ◽  
pp. 1768-1785 ◽  
Author(s):  
Alexander Kalyukin ◽  
Sebastian Kohl
Keyword(s):  
Urban Housing ◽  
Regional Differentiation ◽  
Differential Growth ◽  
Living Space ◽  
Housing Characteristics ◽  
Per Capita ◽  
Soviet Legacy ◽  
Almost All ◽  
Over Time

Did the socialist experiment disrupt continuity in Russian urban housing? Based on a unique collection of urban data covering several hundred Russian cities and spanning three regimes across more than a century, this paper gives a nuanced account of continuities and discontinuities of housing in post-Soviet cities. Three main housing characteristics are analysed: urban density (persons per building and living space per capita), ownership structure and the modernisation of stock (building material and provision with amenities). Although all Russian cities underwent a number of major shocks and regime changes during the course of the 20th century, their rankings with regard to these three key housing characteristics are still significantly correlated over time, whereas living space per capita is largely uncorrelated over time. This holds true despite significant convergence processes in almost all dimensions and also when including contemporary control variables. We hypothesise that local or regional building traditions, regional differentiation in Soviet urban planning as well as Soviet land use specificities could explain differential growth across cities. Going beyond existing late-Soviet-legacy timeframes, the long-term perspective reveals that even major regime shocks did not completely erase regionally shaped patterns in housing conditions.

Observations on Flounders Pleuronectes Flesus L. Marked in the Esturaries of the Tamar and Lynher

1947 ◽  
Vol 27 (1) ◽  
pp. 53-64 ◽  
Author(s):  
P. H. T. Hartley
Keyword(s):  
Growth Rates ◽  
The Other ◽  
Individual Growth ◽  
Limited Area ◽  
English Channel ◽  
Immature Fish

1039 flounders were marked with numbered vulcanite disks in the estuaries of the Tamar and Lynher.148 flounders were recaptured and of these seven fish were recovered a second time after one recovery and release, and one fish was recaptured on three occasions after two previous recoveries and releases.Only two fish were recovered at a distance from Plymouth. Both had moved eastward, up the English Channel.There was little or no growth in the winter months.Individual growth rates were found to vary greatly.The flounders living in the last reach of the Tamar near Saltash tended to remain in one limited area during the winter months, save for a drift down-stream of some of the larger fish. In the spring there was an upstream movement of the smaller, immature fish.Flounders which had gone down to the sea to spawn might return to the river in which they were marked, or to the other river of the two which join to form the Hamoaze, or they might move right away from the area where they were marked.

DNA Barcoding and Biometric Investigation on the Invasive Oreochromis niloticus (Linnaeus, 1758) from the River Yamuna of Uttar Pradesh

2020 ◽  
Author(s):  
Absar Alam ◽  
Narinder Kumar Chadha ◽  
Annam-Pavan Kumar ◽  
Sushant Kumar Chakraborty ◽  
Kripal Datt Joshi ◽  
...  
Keyword(s):  
Oreochromis Niloticus ◽  
Dna Barcode ◽  
Taxonomic Status ◽  
River System ◽  
B Value ◽  
Coi Gene ◽  
Differential Growth ◽  
Male And Female ◽  
Total Length ◽  
River Yamuna

Oreochromis niloticus (Linnaeus, 1758), an invasive fish species is rapidly spreading in the Gangetic river system. The aim of the study was to identify and confirm its identity at species level by establishing a barcoding reference datasets in the river Yamuna and then to investigate its morphometric, meristic traits and length-weight relationship of O. niloticus from the Allahabad water of the river Yamuna by the examination of 341 fish specimens collected during October 2011 to September 2012. The taxonomic status of O. niloticus (Linnaeus, 1758), in the river Yamuna was assessed using DNA barcode marker COI gene sequences, have clearly identified the O. niloticus species with 100% similarity value with public database. The length-weight relationships were established as W = 0.029486L2.881638 and W = 0.058499L2.661735 for male and female. Differential growth in length-weight between male and female of O. niloticus were significant (p less than 0.05), with a greater slope (b) value for male (2.88) than female (2.66). The t statistics estimated for the regression coefficients (b) were significant at 5% level of significance (p less than 0.05), indicating an allometric growth pattern. The correlation was highest for the standard length and the total length (0.9878) and minimum for caudal peduncle length and total length (0.8022). Fin formula based on the meristic studies can be written as B3, D 15-19/11-15, P14, V 1/5, A 3/8-11 and C16-22.

DEVELOPMENT OF TIPHODYTES GERRIPHAGUS (HYMENOPTERA: SCELIONIDAE) IN LIMNOPORUS DISSORTIS EGGS (HEMIPTERA: GERRIDAE)

1999 ◽  
Vol 131 (2) ◽  
pp. 219-228 ◽  
Author(s):  
João M. Sousa
Keyword(s):  
Sex Ratio ◽  
Larval Stage ◽  
Host Feeding ◽  
Larval Instars ◽  
Pupal Period ◽  
Laboratory Conditions ◽  
Total Length ◽  
Preimaginal Development ◽  
First Instar ◽  
Mandible Length

AbstractInvestigations of preimaginal development in Tiphodytes gerriphagus Marchal reveal two larval instars, based on counting exuviae and comparing mandible length during development within Limnoporus dissortis Drake & Harris eggs. Tiphodytes gerriphagus eggs are stalked, as is typical of scelionids, and are 282.6 ± 3.48 μm (mean ± SE) long. The chorion ruptures at 8–9 h postoviposition and releases a nonfeeding embryo into the host. Feeding begins at 18–20 h postoviposition, after the embryonic cuticle is shed and a fully differentiated and active larva is released. The first larval stage is teleaform and lasted up to 5 days postoviposition, and its total length increased from 183.6 ± 3.35 to 517.0 ± 14.67 μm. The second larval stage is hymenopteriform and lasted from 5 to 13 days postoviposition, and grew from 920.2 ± 24.65 to 1352.4 ± 11.89 μm total length before pupating. The pupal period lasted about 11 days, with male pupae being shorter and thinner than female pupae. These findings differ from previous descriptions of T. gerriphagus, and it is suspected that the first instar was mistakenly divided into two stadia. The sex ratio under laboratory conditions was female biased (22% males), and males were smaller but did not emerge significantly earlier than females.

scholarly journals Alternative Migratory Strategies Related to Life History Differences in the Walleye (Sander Vitreus)

2021 ◽  
Author(s):  
Graydon McKee ◽  
Rachael Hornsby ◽  
Friedrich Fischer ◽  
Erin S. Dunlop ◽  
Robert Mackereth ◽  
...  
Keyword(s):  
Life History ◽  
Acoustic Telemetry ◽  
Late Summer ◽  
Maximum Size ◽  
Individual Growth ◽  
Sander Vitreus ◽  
Differential Growth ◽  
Individual Behaviour ◽  
Pace Of Life ◽  
Average Maximum

Abstract BackgroundWhile Pace of Life Syndrome predicts behavioural differences between individuals with differential growth and survival, testing these predictions in nature is challenging due to difficulties with measuring individual behaviour in the field. However, recent advances in acoustic telemetry technology have facilitated measurements of individual behaviour at scales not previously possible in aquatic ecosystems. MethodsUsing a Walleye (Sander vitreus) population inhabiting Black Bay, Lake Superior, we examine whether life history characteristics differ between more and less mobile individuals as predicted by Pace of Life Syndrome. We tracked the movement of 192 individuals from 2016-2019 using an acoustic telemetry study, relating patterns in annual migratory behaviour to individual growth, and seasonal changes in optimal thermal-optical habitat. ResultsWe observed two consistent movement patterns in our study population — migratory individuals left Black Bay during late summer to early fall before returning to the bay, whereas residents remained within the bay year-round. The average maximum length of migrant Walleye was 5.5 cm longer than residents, and the sex ratios of Walleye caught during fall surveys was increasingly female-biased towards the mouth of Black Bay, suggesting that a majority of migrants were females. Further, Walleye occupancy outside of Black Bay was positively associated with increasing thermal-optical habitat. ConclusionsWalleye in Black Bay appear to conform to Pace of Life Syndrome, with more exploratory (migrant) individuals gaining increased fitness through increased maximum size, which, given size-dependent fecundity in this species, likely results in greater reproductive success (via greater egg deposition vs. non-migrants). Further, apparent environmental (thermal) controls on migration suggest that migratory Walleye (more so than residents) may be more sensitive to changing environmental conditions (e.g., warming climate) than residents.

scholarly journals Evidence of a relationship between weight and total length of marine fish in the North-eastern Atlantic Ocean: physiological, spatial and temporal variations

2016 ◽  
Vol 98 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Kélig Mahé ◽  
Elise Bellamy ◽  
Jean Paul Delpech ◽  
Coline Lazard ◽  
Michèle Salaun ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Sea ◽  
Temporal Variations ◽  
Bay Of Biscay ◽  
English Channel ◽  
Total Length ◽  
The North ◽  
Eastern Atlantic Ocean ◽  
North Eastern ◽  
The North Sea

Weight–Body Length relationships (WLR) of 45 fish species (37 Actinopterygii and eight Elasmobranchii) were investigated. A total of 31,167 individuals were caught and their biological parameters measured during the four quarters from 2013 to 2015, on five scientific surveys sampling the North-eastern Atlantic Ocean from the North Sea to the Bay of Biscay (ICES Divisions IVb, IVc, VIId, VIIe, VIIg, VIIh, VIIj, VIIIa and VIIIb). Among 45 tested species, all showed a significant correlation between total length (L) and total weight (W). The influence of sex on WLR was estimated for 39 species and presented a significant sexual dimorphism for 18 species. Condition factor (K) of females was always higher than for males. Moreover, a spatial effect on the WLR according to five ecoregions (the Bay of Biscay, the Celtic Sea, the Western English Channel, the Eastern English Channel and the North Sea), was significant for 18 species among 38 tested species. The temporal effect was tested according to components (year and quarter/season). The seasonality effect on WLR is more frequently significant than the year especially for the Elasmobranchii species, and can be related to the spawning season. Finally, depressiform species (skates, sharks and flatfish) are characterized by positive allometric growth, whereas there is no such clear pattern regarding roundfishes growth, whatever their body shape is.

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