The copepod width–weight relation and its utility in food chain research

1980 ◽  
Vol 58 (10) ◽  
pp. 1884-1891 ◽  
Author(s):  
Sifford Pearre Jr.
Keyword(s):  
Food Chain ◽  
Prey Selection ◽  
Linear Size ◽  
Size Parameter ◽  
Prosome Length ◽  
Body Width ◽  
Total Length ◽  
Linear Dimensions ◽  
Controlling Parameter ◽  
Wet Weight

A review of several methods for estimating copepod wet weight from linear dimensions shows that, as expected, precision in estimation is gained at the expense of generality. Body width, however, is a better estimator of wet weight than either total length or prosome length and is less ambiguous in use.Body width is also the controlling parameter in prey selection by many important marine and freshwater predators including birds, fish, and some plankters. For estimating ingested prey biomass it thus seems the best single linear size parameter.

scholarly journals Soft bodies make estimation hard: correlations among body dimensions and weights of multiple species of sea cucumbers

2015 ◽  
Vol 66 (10) ◽  
pp. 857 ◽  
Author(s):  
James Prescott ◽  
Shijie Zhou ◽  
Andhika P. Prasetyo
Keyword(s):  
Power Function ◽  
Body Length ◽  
Sea Cucumber ◽  
Dry Weight ◽  
Basic Knowledge ◽  
Small Scale ◽  
Body Width ◽  
Sea Cucumbers ◽  
Body Dimensions ◽  
Wet Weight

Tropical sea cucumbers are commonly exploited by small-scale, poorly managed fisheries. A fundamental problem in managing sea cucumber fisheries is the lack of basic knowledge of important life history characteristics for most species. As a result of plastic body dimensions, biological research on this group of animals becomes exceptionally challenging. To improve our understanding of essential biological parameters, we conducted a study to investigate correlations among various body measurements. We analysed a total of 18 sea cucumber species and more than 6600 individuals collected at Scott Reef in the Timor Sea, north-west Australia. We used hierarchical Bayesian errors-in-variables models to specifically take into account measurement errors that are obviously unavoidable. The measures included three types of weights (wet weight, gutted weight and dry weight) and two body dimensions (length and width). The modelling reveals that using both body length and width as independent variables, wet weight increases approximately linearly with body length, but is a power function (~1.6) of body width, although variability exists among species. Dry weight tends to increase more slowly with body length, but has a similar power function of body width. Linear relationships are established between the three types of weights. On average, ~11% of a live specimen and ~16% of a gutted specimen is processed to the commercially traded dry body wall. Our results can be applied to sea cucumbers in other areas and can be useful for data standardisation and size-based fisheries management.

Mercury concentrations of the axial muscle tissues of some marine fishes of the continental shelf adjacent to Tasmania

1985 ◽  
Vol 36 (4) ◽  
pp. 509 ◽  
Author(s):  
JD Thomson
Keyword(s):  
Total Mercury ◽  
Marine Fishes ◽  
Management Tool ◽  
Published Data ◽  
Organic Mercury ◽  
Commercial Fish ◽  
Total Length ◽  
Muscle Tissues ◽  
Wet Weight ◽  
Health Regulations

The mercury concentrations of 35 commercial and potentially commercial fish species from Tasmanian waters were determined. Four species had mean total mercury concentrations above 0.5 mg kg-1 wet weight and in all four there were individuals with concentrations above 1.5 mg kg-1 wet weight. Two species of shark, Parascyllium ferrugineum and Cephaloscyllium laticeps (with sample sizes of 4 and 1, respectively), had total mercury concentrations above the limit of a mean of 1.0 mg kg-1 wet weight set by the Tasmanian Public Health regulations. Concentrations in the species were compared with published data. Organic mercury concentrations in different species ranged from 40 to 96% of the total mercury concentrations. In fewer than half the species were total mercury concentration and total length or weight significantly correlated, indicating that neither total length nor weight could be used as a universal management tool to control human mercury intake from fish consumption.

scholarly journals Length-Length and Length-Weight Relationships in Nephrops norvegicus from the Aegean Sea (Linnaeus, 1758)

2011 ◽  
Vol 12 (1) ◽  
pp. 121
Author(s):  
I. AYDIN ◽  
C. AYDIN
Keyword(s):  
Carapace Length ◽  
Aegean Sea ◽  
Body Width ◽  
Nephrops Norvegicus ◽  
Frequency Distributions ◽  
Total Length ◽  
Size Frequency ◽  
Length Width

The objective of this study was to determine the length-length, length-width and length-weight relationships inNephrops norvegicus as a basis for conversions. A total of 659 specimens were collected with trawl gears from the commercial trawler “Hapuloğlu” between 17 and 21 August 2008 in international waters of the middle Aegean Sea. Morphometric equations for the conversions of length and weight were constructed for females, males, and combined sexes. Females were generally smaller than males, and size-frequency distributions total length (TL), carapace length (CL), and body width (BW) revealed significant differences between females and males

scholarly journals Marine amphipods as a new live prey for ornamental aquaculture: exploring the potential of Parhyale hawaiensis and Elasmopus pectenicrus

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10840
Author(s):  
Jorge Arturo Vargas-Abúndez ◽  
Humberto Ivan López-Vázquez ◽  
Maite Mascaró ◽  
Gemma Leticia Martínez-Moreno ◽  
Nuno Simões
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Energy Content ◽  
Dry Weight ◽  
Fish Diet ◽  
Juvenile Growth ◽  
Total Length ◽  
Gross Energy ◽  
Wet Weight ◽  
Ornamental Species

Marine amphipods are gaining attention in aquaculture as a natural live food alternative to traditional preys such as brine shrimps (Artemia spp.). The use of Artemia is convenient for the culture of many marine species, but often problematic for some others, such as seahorses and other marine ornamental species. Unlike Artemia, marine amphipods are consumed by fish in their natural environment and show biochemical profiles that better match the nutritional requirements of marine fish, particularly of polyunsaturated fatty acids (PUFA), including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Despite their potentially easy culture, there are no established culture techniques and a deeper knowledge on the reproductive biology, nutritional profiles and culture methodologies is still needed to potentiate the optimization of mass production. The present study assessed, for the first time, the aquaculture potential of Parhyale hawaiensis and Elasmopus pectenicrus, two cosmopolitan marine gammarids (as per traditional schemes of classification) that naturally proliferate in the wild and in aquaculture facilities. For that purpose, aspects of the population and reproductive biology of the species were characterized and then a series of laboratory-scale experiments were conducted to determine amphipod productivity, the time needed to reach sexual maturity by hatchlings (generation time), cannibalism degree, the effects of sex ratio on fecundity and the effects of diet (shrimp diet, plant-based diet and commercial fish diet) on fecundity and juvenile growth. P. hawaiensis, unlike E. pectenicrus, was easily maintained and propagated in laboratory conditions. P. hawaiensis showed a higher total length (9.3 ± 1.3 mm), wet weight (14.4 ± 6.2 mg), dry weight (10.5 ± 4.4 mg), females/males sex ratio (2.24), fecundity (12.8 ± 5.7 embryos per female), and gross energy content (16.71 ± 0.67 kJ g-1) compared to E. pectenicrus (7.9 ± 1.2 mm total length; 8.4 ± 4.3 mg wet weight; 5.7 ± 3.2 mg dry weight; 1.34 females/males sex ratio; 6.5 ± 3.9 embryos per female; 12.86 ± 0.82 kJ g−1 gross energy content). P. hawaiensis juvenile growth showed a small, but significant, reduction by the use of a plant-based diet compared to a commercial shrimp and fish diet; however, fecundity was not affected, supporting the possible use of inexpensive diets to mass produce amphipods as live or frozen food. Possible limitations of P. hawaiensis could be their quite long generation times (50.9 ± 5.8 days) and relatively low fecundity levels (12.8 ± 5.7 embryos per female). With an observed productivity rate of 0.36 ± 0.08 juveniles per amphipod couple per day, P. hawaiensis could become a specialty feed for species that cannot easily transition to a formulated diet such as seahorses and other highly priced marine ornamental species.

Feeding habits and prey selection by the skate Dipturus chilensis (Elasmobranchii: Rajidae) from the south-western Atlantic

2000 ◽  
Vol 80 (5) ◽  
pp. 953-954 ◽  
Author(s):  
Luis O. Lucifora ◽  
Juan L. Valero ◽  
Claudia S. Bremec ◽  
Mario L. Lasta
Keyword(s):  
Prey Selection ◽  
Feeding Habits ◽  
The South ◽  
Western Atlantic ◽  
Total Length ◽  
Mouth Width ◽  
Merluccius Hubbsi ◽  
Illex Argentinus ◽  
Nototheniid Fish

The diet of Dipturus chilensis was composed mainly of the nototheniid fish Patagonotothen ramsayi, squid Illex argentinus, hake Merluccius hubbsi, serolid isopods, and crustaceans. Our results suggest that D. chilensis feeds selectively on some teleosts and rejects eel-like fishes. Total length of consumed P. ramsayi was significantly correlated with the skate's mouth width.

Dietary Change during Development in the Freshwater Calanoid Copepod Epischura lacustris Forbes

1986 ◽  
Vol 43 (5) ◽  
pp. 938-944 ◽  
Author(s):  
Patricia Chow-Fraser ◽  
C. Kim Wong
Keyword(s):  
Developmental Stage ◽  
Calanoid Copepod ◽  
Developmental Stages ◽  
Adult Stage ◽  
Prey Selection ◽  
Ingestion Rate ◽  
Grazing Rate ◽  
Linear Dimensions ◽  
Selection For ◽  
Omnivorous Diet

The diet of the freshwater calanoid copepod Epischura lacustris from C2 to adult stage was examined with predation experiments, grazing experiments, and stomach content analyses. There was a transition from an exclusively herbivorous diet in early copepodid stages to an omnivorous diet in adults. Laboratory predation experiments revealed that C2 and C3 were incapable of ingesting Bosmina (0.25–0.35 mm), but from C4 to C6, ingestion rate of Bosmina increased with developmental stage. The order or prey selection for adult Epischura was Bosmina over Diaptomus and Cyclops. Grazing rate on small algae (<10 μm) increased with developmental stage. Zooplankton remains were only found in the guts of stages older than C2; cladocerans and crustacean eggs were the most common zooplankton food. Algae with longest linear dimensions greater than 10 μm (e.g. Sphaerocystis, Dinobryon, and diatoms) were common in the guts of all developmental stages of Epischura. The occurrence of small unicells (<10 μm) in the guts decreased with developmental stage.

scholarly journals Chaos in a Hybrid Food Chain Model

2021 ◽  
pp. 2362-2368
Author(s):  
Safaa Jawad Ali ◽  
Abed Almohsen Naji Almohasin ◽  
Adwea Naji Atewi ◽  
Raid Kamel Naji ◽  
Norihan Md Arifin
Keyword(s):  
Global Stability ◽  
Food Chain ◽  
Direct Method ◽  
Equilibrium Points ◽  
Chain Model ◽  
Lyapunov Direct Method ◽  
Type Iv ◽  
Controlling Parameter ◽  
Periodic Dynamics ◽  
Food Chain Model

In this paper, chaotic and periodic dynamics in a hybrid food chain system with Holling type IV and Lotka-Volterra responses are discussed. The system is observed to be dissipative. The global stability of the equilibrium points is analyzed using Routh-Hurwitz criterion and Lyapunov direct method. Chaos phenomena is characterized by attractors and bifurcation diagram. The effect of the controlling parameter of the model is investigated theoretically and numerically.

Biomechanics of rheotaxis in six teleost genera

2006 ◽  
Vol 84 (8) ◽  
pp. 1173-1186 ◽  
Author(s):  
Robert W. Blake
Keyword(s):  
Lift Coefficient ◽  
Body Width ◽  
Total Length ◽  
Morphological Adaptations ◽  
Maximal Height ◽  
Dead Fish ◽  
Optimal Values ◽  
Lift And Drag ◽  
Frictional Coefficients ◽  
First Time

Biomechanical, behavioural, and morphological adaptations affecting lift and drag on tropical stream fish (five loricariids and one gyrinocheilid) are analyzed. The drag on fish attached to a surface is directly measured for the first time, allowing the lift coefficient to be inferred. Mean drag coefficients (0.2–0.9, based on projected frontal area) are 2 to 30 times the equivalent frictional coefficients for laminar flow for smooth blisters attached to a surface. Fineness ratios (total length / maximal height, l/h = 6.7–9.0), flattening (maximal body width / maximal height, b/h = 0.9–2.0), and lengthening (distance from end of rostrum to maximal height / total length, x/l = 0.17–0.22) are similar to optimal values for technical bodies of low drag (smooth blisters attached to surfaces: 10, 2, and 0.3 for l/h, b/h, and x/l, respectively). The station-holding ability of Gyrinocheilus aymonieri (Tirant, 1883) (closed oral sucker) is compared with that of the loricariids (open oral suckers) using live and dead slipping velocities (Vlive and Vdead; water velocity at which live and dead fish first move backwards against the current, respectively) measured on a smooth Perspex® surface. Gyrinocheilus aymonieri has the greatest station-holding ability (Vlive = 59.1 cm·s–1, Vlive – Vdead = 45.7 cm·s–1). Fish with high Vdead and low Vlive – Vdead values rely more on frictional devices (e.g., spines and odontodes) for station-holding than on oral suction (e.g., fish of the genera Otocinclus Cope, 1871 and Hypostomus Lacépède, 1803), whereas those with low Vdead and high Vlive – Vdead values place a greater emphasis on suction (e.g., G. aymonieri and the genus Pterygoplichthys Gill, 1858). Stream fishes maximize slipping speed through high densities (1.06–1.15 g·cm–3), high frictional coefficients (0.12–1.2 on a Perspex® surface), and high rheotactic suction pressures (26–173 Pa). In addition, a negative lift coefficient of –0.5 is calculated for the genus Chaetostoma von Tschudi, 1846.

STUDY OF LINEAR DIMENSIONS OF CORN SEEDS

2020 ◽  
Author(s):  
D.A. Voropaev ◽  
◽  
H.O. Khoshafian ◽  
Keyword(s):  
Size Distribution ◽  
Seed Size ◽  
Linear Size ◽  
Statistical Characteristics ◽  
Linear Dimensions

The article analyzes the linear size of the seeds of corn sorts Mansanta and Krasnodar 194 MV. Statistical characteristics and size relationships for each seed size are determined. Empirical histograms and theoretical functions of seed size distribution are constructed. The degree of correlation between seedsizes was determined.

PRELIMINARY STUDIES ON RED BELLY TILAPIA COPTODON ZILLII CAUGHT FROM OYAN DAM, OGUN STATE, NIGERIA

2019 ◽  
Vol 18 (1) ◽  
pp. 1-15
Author(s):  
A. A. IDOWU ◽  
W. O. ABDUL ◽  
W. O. ABDUL ◽  
A. A. ALIMI ◽  
M. O. TIJANI
Keyword(s):  
Body Weight ◽  
Standard Length ◽  
Head Length ◽  
Body Width ◽  
Body Depth ◽  
Snout Length ◽  
Food Items ◽  
Total Length ◽  
Ogun State ◽  
Eye Diameter

The study was carried out on the biological aspect of Redbelly Tilapia, Coptodon zillii collected from Oyan Lake, Abeokuta North Local Government Area, Ogun State, Nigeria, with the aim of contributing to the baseline data for carrying out further studies on its ecology, conservation and development. A total of two hundred and fifty four fish (254) specimens were caught from the Ibaro landing site of the Lake between March and July, 2015. The total length (cm), standard length (cm), head length (cm), body width (cm), body depth (cm), snout length (cm), eye diameter (cm) and body weight (g) were measured. The stomach content was also assessed in order to determine its food and feeding habit. The mean total-length, standard-length, head-length, eye-diameter, snout-length, body-depth, body-width and body-weight during the study were 10.98±0.61cm, 8.56±0.14cm, 2.5±0.08cm, 3.67±0.15cm, 1.52±0.11cm,1.37±0.17cm, 4.05±0.07cm, 34.25±3.02g respectively and their ranges were (4.5-18.7cm), (3.2-15.2cm), (1.1-5.8cm), (2.0-6.8cm), (0.8-3.0cm), (1.1-4.8cm), (1.4-7.3cm) and (6.0-132.0g). A negative allometric (b<3) growth pattern was observed for the stock. The meristic characteristics of C. zillii were (DFR) XIV 10 – XVI 14; PVR, AFR III 8 –III 9; PFR 10 – 13 respectively. Stomach analysis showed that diatoms were the most abundant food items in the diet of C. zillii numerically, 29.98%, while desmids were the most abundant food items in terms of frequency occurrence, 27.82%. This study concluded that C. zillii is not morphometrically and meristically different from the already classified from previous studies. Also, C. zillii thrives well on available plants and detritus.    

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