Piscivory, Growth, and Size-Selective Mortality of Age 0 Pikeperch (Stizostedion lucioperca)

1992 ◽  
Vol 49 (5) ◽  
pp. 894-902 ◽  
Author(s):  
Anthonie D. Buijse ◽  
Rob P. Houthuijzen
Keyword(s):  
Frequency Distribution ◽  
Energy Content ◽  
Stomach Contents ◽  
Proximate Analysis ◽  
Skewed Distribution ◽  
Fish Length ◽  
Growth And Survival ◽  
Class Strength ◽  
Highly Correlated ◽  
Stizostedion Lucioperca

Year-class strength of pikeperch (Stizostedion lucioperca), indexed as the age 0 abundance in trawl surveys, varied 300-fold in the northern part of Lake IJssel, The Netherlands, over the period 1966–89. Both mean length and year-class strength of age 0 pikeperch in November were highly correlated with mean summer temperature. Depending on the environmental conditions, especially water temperature and availability of food, the initially unimodal length frequency distribution of age 0 pikeperch developed into a positively skewed, bimodal or negatively skewed distribution towards the end of the summer. Strong year-classes were characterised by larger mean lengths and a negatively skewed frequency distribution, while weak year-classes were smaller and positively skewed. Stomach contents consisted of zooplankton and macrofauna for the smaller specimens and of age 0 smelt (Osmerus eperlanus) for the larger pikeperch (> 10 cm). Body energy content increased with fish length, and differences in proximate analysis were more pronounced later in the season. The condition of nonpiscivorous age 0 pikeperch was low and decreased over time, while that of piscivorous pikeperch increased. The onset of piscivory, favoured by high temperatures during summer, has a direct positive effect on the growth and survival of age 0 pikeperch.

Bias in Using an Age–Length Key to Estimate Age-Frequency Distributions

1978 ◽  
Vol 35 (2) ◽  
pp. 184-189 ◽  
Author(s):  
S. J. Westrheim ◽  
W. E. Ricker
Keyword(s):  
Frequency Distribution ◽  
Age Distribution ◽  
Length Distribution ◽  
Fish Population ◽  
Systematic Bias ◽  
Parental Age ◽  
Frequency Distributions ◽  
Class Strength ◽  
Key Words Age ◽  
Age Frequency Distribution

Consider two representative samples of fish taken in different years from the same fish population, this being a population in which year-class strength varies. For the "parental" sample the length and age of the fish are determined and are used to construct an "age–length key," the fractions of the fish in each (short) length interval that are of each age. For the "filial" sample only the length is measured, and the parental age–length key is used to compute the corresponding age distribution. Trials show that the age–length key will reproduce the age-frequency distribution of the filial sample without systematic bias only if there is no overlap in length between successive ages. Where there is much overlap, the age–length key will compute from the filial length-frequency distribution approximately the parental age distribution. Additional bias arises if the rate of growth if a year-class is affected by its abundance, or if the survival rate in the population changes. The length of the fish present in any given part of a population's range can vary with environmental factors such as depth of the water; nevertheless, a sample taken in any part of that range can be used to compute age from the length distribution of a sample taken at the same time in any other part of the range, without systematic bias. But this of course is not likely to be true of samples taken from different populations of the species. Key words: age–length key, bias, Pacific ocean perch, Sebastes alutus

scholarly journals EFFECTS OF DIFFERENT pH SETTINGS ON GROWTH AND SURVIVAL OF COMMON CARP RAJADANU STRAIN

2018 ◽  
Vol 13 (2) ◽  
pp. 57 ◽  
Author(s):  
Vitas Atmadi Prakoso ◽  
Deni Radona
Keyword(s):  
Survival Rate ◽  
Common Carp ◽  
Culture Media ◽  
Stocking Density ◽  
Quality Parameters ◽  
Fish Length ◽  
Total Biomass ◽  
Growth And Survival ◽  
Fish Group ◽  
Ph Range

pH is one of the important water quality parameters in aquaculture. This study aimed to observe the growth performance and survival rate of common carp (Cyprinus carpio) Rajadanu strain reared in culture media with different pH levels. Fish (length: 3.60 ± 0.18 cm; weight: 1.68 ± 0.18 g) were stocked in nine aquariums (40 cm x 40 cm x 30 cm) for 10 days with a stocking density of 25 fish per aquarium. The treatments used were (A) pH 4-5, (B) pH 5-6, and (C) pH 6-7, with three replications. A commercial feed containing 28% protein was given daily and as much as 3% of the total biomass. The observed data were analyzed using variance analysis (ANOVA), followed by Duncan test. The results showed that the pH treatments did not affect the growth (length and weight) and survival rate of common carp Rajadanu strain (P>0.05). The best growth was achieved by the fish group reared in water with a pH range of 6-7 (length = 0.38 cm; weight = 0.17 g). The highest survival was attained by the fish group reared in water with a pH range of 5-6 (90.66%).

scholarly journals Match–Mismatch Regulation for Bluegill and Yellow Perch Larvae and Their Prey in Sandhill Lakes

2010 ◽  
Vol 1 (2) ◽  
pp. 73-85 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
David W. Willis ◽  
Richard S. Holland
Keyword(s):  
Yellow Perch ◽  
Prey Selection ◽  
Larval Fish ◽  
Lepomis Macrochirus ◽  
Perca Flavescens ◽  
Stomach Contents ◽  
Zooplankton Abundance ◽  
Growth And Survival ◽  
Fish Recruitment ◽  
Newly Hatched Larvae

Abstract Food availability may regulate fish recruitment, both directly and indirectly. The availability of zooplankton, especially to newly hatched larvae, is thought to be crucial to their early growth and survival. We examined stomach contents of larval bluegill Lepomis macrochirus and yellow perch Perca flavescens in Pelican Lake and Cameron Lake, Nebraska, in 2004 and 2005. We also determined zooplankton availability and calculated prey selection using Chesson's α. In addition, we investigated potential match–mismatch regulation of recruitment from 2004 to 2008. Bluegill positively selected copepod nauplii and Bosmina spp., and yellow perch often selected copepods. Abundant zooplankton populations were available for consumption. Matches of both larval bluegill and yellow perch abundance to zooplankton abundance were detected in all years; exact matches were common. Mismatches in predator and prey production were not observed. Predation by age-0 yellow perch on age-0 bluegill was not observed, even though yellow perch hatched 2 mo prior to bluegill. Given that zooplankton were abundant and well-timed to larval fish relative abundance over the time span of this study, the match–mismatch hypothesis alone may not fully account for observed recruitment variability in these populations. Environmental conditions may also affect recruitment and warrant further investigation.

Paddlefish: Ecological, Aquacultural, and Regulatory Challenges of Managing a Global Resource

2019 ◽  
Author(s):  
Keyword(s):  
Reproductive Success ◽  
River Discharge ◽  
First Year ◽  
Side Channel ◽  
Fish Length ◽  
Detailed Understanding ◽  
Successful Recruitment ◽  
Class Strength ◽  
In The Wild ◽  
Key Features

<i>Abstract</i>.—Inadequate recruitment is a concern in many stocks of Paddlefish <i>Polyodon spathula</i>. Despite the importance of maintaining adequate recruitment, little understanding exists of specific recruitment factors and mechanisms. In this chapter we review and synthesize the results of the relatively few studies and observations of Paddlefish reproduction and recruitment and the factors potentially responsible for observed variations. Comparisons are made with studies on sturgeons. Although Paddlefish and sturgeon show many anatomical, life history, and behavioral similarities, some key features of Paddlefish differing from other Acipenseriform species are lifelong zooplanktivory, filter feeding, midwater foraging behaviors, and lack of armoring. Data from both sturgeon and Paddlefish show higher reproductive success associated with higher river discharge; greater Paddlefish reproductive success in some adfluvial populations has also been linked to increasing and high reservoir levels. Whereas several sturgeon studies suggest that recruitment (and year-class strength) are determined within 2–3 months of hatching, results from Paddlefish suggest that year-class strength may be determined later in their first year or in their second year. Observations and field results lead to the hypothesis that young Paddlefish must grow fast in their first and early second years of life to reach a size where they can successfully overwinter, avoid predation from piscivorous fishes and birds, and recruit. Support for this grow-fast-or-be-eaten hypothesis comes from several sources, both indirect (e.g., the relation between fish length and rostrum length) and direct (higher survival of larger fish released and higher lipids in age-0 fish in years of good recruitment). However, more research is needed to adequately test this hypothesis. Paddlefish rearing habitat changes include river-backwater and side-channel sedimentation, reservoir sedimentation and aging, and threats from increased native and nonnative predator populations. Managers of Paddlefish will need a more detailed understanding of the habitat conditions needed for successful recruitment in the wild.

scholarly journals Nutritional Composition and Physio-Chemical Properties of Peeled and Unpeeled Yam Flour (White Yam, Dioscorea rotundata)

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 735-735
Author(s):  
Oyetunji Akinola
Keyword(s):  
Sensory Evaluation ◽  
Energy Content ◽  
Chemical Properties ◽  
Proximate Analysis ◽  
Nutritional Composition ◽  
Water Soluble ◽  
Nutrient Deficiencies ◽  
Two Samples ◽  
Significant Difference ◽  
Yam Flour

Abstract Objectives The main shelf-stable product of yam is the traditional yam flour (elubo), Yams (Dioscorea spp.) which are regarded as traditional foods are consumed in various ways but majorly consumed as yam flour in the south west region of Nigeria. This study investigated the physical, functional and sensory properties and anti-nutrients contents of peeled and unpeeled yam flour. Methods Yam bought in the popular market production procedures were followed, washing, peeling and slicing, parboiling, steeping. draining, drying, milling, and packaging for peeled yam and unpeeled yam peeling was not included in the process, the two samples were analyzed chemically according to the official methods of analysis described by the Association of Official Analytical Chemist as well as sensory evaluation. Results The results of the study confirmed the significant difference in the micro nutrients content of peeled and unpeeled yam flour in fats and water soluble vitamins respectively (K µg/100 g = 6.97,11.83, Fe(mg/kg) = 95.2, 126.9, minerals content Zn(mg/kg) 13.48, 22.92, Fe(mg/kg) 95.2126.9 and anti-nutrient properties of the ‘Amala’ made from the two products (peeled and unpeeled yam flour) the percentage of Tannin 0.0023, 0.0010 and Hydrocynaide (mg/kg) 0.92, 1.01.The proximate analysis of unpeeled yam four indicated a high value than that of peeled yam flour in protein (2.47, 2.28), fats (1.86, 0.54), ash (3.59, 2.32), and fibre (3.09, 1.31) of both samples respectively but the energy content derived from the ‘amala’ made from unpeeled yam flour is lesser to that of peeled yam flour. Significant exist between the two samples in sensory evaluation of taste, texture, color, mouldability, aroma and general acceptability. Conclusions The result shown that the consumption of unpeeled yam flour can be useful in treatment of nutrient deficiencies diseases. Funding Sources Self.

Digenean parasite communities in flatfishes of the Scotian Shelf and southern Gulf of St. Lawrence

1982 ◽  
Vol 60 (11) ◽  
pp. 2804-2811 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Feeding Behavior ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Parasite Prevalence ◽  
Winter Flounder ◽  
Fish Length ◽  
Pseudopleuronectes Americanus ◽  
Scotian Shelf ◽  
Yellowtail Flounder ◽  
Limanda Ferruginea

Prevalence of digenean parasites in four major flatfishes of the Scotian Shelf and southern Gulf of St. Lawrence, American plaice (Hippoglossoides platessoides), yellowtail flounder (Limanda ferruginea), witch flounder (Glyptocephalus cynoglossus), and winter flounder (Pseudopleuronectes americanus), is compared between hosts in relation to geographic distribution, season, feeding behavior, and fish length. The 13 parasite species indicate overlap of feeding habits among hosts but also considerable diversity in feeding behavior, supporting the evidence from examination of stomach contents. Prevalence of digeneans in different final hosts varied between geographic areas and may be used to characterize the populations of the comparatively sedentary flatfish populations. Seasonal variation in prevalence was consistent from area to area but differed between parasites, from the expected increase in summer in some, concomitant with increased feeding, to a winter increase in others, probably related to a seasonal change of diet. Fish length had little effect on parasite prevalence in yellowtail flounder and witch flounder but had a notable effect on plaice and winter flounder from the Gulf of St. Lawrence, again apparently related to change of diet.

Fish on the roof of the world: densities, habitats and trophic position of stone loaches (Triplophysa) in Tibetan streams

2017 ◽  
Vol 68 (1) ◽  
pp. 53 ◽  
Author(s):  
Dean Jacobsen ◽  
Søren Kock Laursen ◽  
Ladislav Hamerlik ◽  
Karen Moltesen ◽  
Anders Michelsen ◽  
...  
Keyword(s):  
Trophic Position ◽  
Stomach Contents ◽  
Benthic Algae ◽  
Stomach Content Analysis ◽  
Food Sources ◽  
Fish Length ◽  
The Tibetan Plateau ◽  
Running Waters ◽  
Ecological Data ◽  
Percentage Cover

The fast increase in temperature on the Tibetan Plateau, with anticipated future changes in aquatic ecosystems and biodiversity, highlights the urgent need for ecological data on the sparsely studied Tibetan running waters. In the present study we surveyed eight Tibetan streams to obtain data on densities, feeding selectivity and trophic position of the stone loach Triplophysa. Benthic algae, detritus, macroinvertebrates and fish were quantified and collected for stable isotope and stomach content analysis. Triplophysa density (mean 0.70 individuals m–2, maximum 1.6 individuals m–2) decreased with altitude and increased with the percentage cover of fine substratum. Glacier-fed sites tended to have the lowest fish densities, whereas the highest densities were found near lakes. Mean fish length (4.1–9.6cm) was positively related to the percentage cover of coarse substratum. Triplophysa was omnivorous, but the composition of the stomach contents varied greatly between sites and among individuals. Algal matter was ingested at most sites, but macroinvertebrates (Chironomidae, Baetidae and Simuliidae) dominated the ingestion (average 50–100%). The trophic position of Triplophysa, identified from δ15N (‰) of the biota, varied between 2.6 and 4.2 among localities (mean 3.6) and was inversely related to the biomass of benthic algae, but unrelated to quantities of other potential food sources.

scholarly journals Energy Potential Study of Some Tropical Wood Species from Nigeria

2019 ◽  
pp. 1-10 ◽  
Author(s):  
J. O. Asibor ◽  
E. P. Akhator ◽  
A. I. Obanor
Keyword(s):  
Wood Species ◽  
Energy Content ◽  
Thermal Conversion ◽  
Volatile Matter ◽  
Proximate Analysis ◽  
Sample Collection ◽  
Energy Potential ◽  
Tropical Wood ◽  
Benin City ◽  
Afzelia Africana

Aims: To carry out experimental study of the energy potential of some tropical wood species. Study Design: It involved sample collection, experimental analysis and numerical validation of the obtained calorific values. Place and Duration of Study: National Centre for Energy Research and Development (NCERD), University of Nigeria, Nsukka, Enugu State, Nigeria between November 2016 and September 2018. Methodology: Wood waste (saw dust) from ten (10) selected tropical wood species sourced from sawmills in Benin City, Nigeria were subjected to proximate analysis, ultimate analysis as well as energy content study. Results: Thermal conversion characteristics of low ash content (0.2 – 2.76%), very high volatile matter (87.51 – 90.94%), low moisture content (8.62 – 10.53%.), relatively high carbon, hydogen and oxygen contents as well as low nitrogen and sulphur contents were observed. Obtained calorific values were validated using three already existing correlations. Conclusion: Among the 10 species studied, Afzelia africana (Apa) was found to be best suited for energy generation while Triplocyton scleroxylon (Obeche) was found to be least suited.

scholarly journals High quality cassava peel® production and its utilization in pig production: A review

2019 ◽  
Vol 46 (3) ◽  
pp. 205-218
Author(s):  
A. O. K. Adesehinwa ◽  
T. A. Amole ◽  
E. Ajayi ◽  
B. A. Makanjuola ◽  
I. Okike
Keyword(s):  
Energy Content ◽  
High Energy ◽  
Blood Parameters ◽  
Proximate Analysis ◽  
Growing Pigs ◽  
Weaned Pigs ◽  
High Quality ◽  
Cassava Peels ◽  
Cassava Peel ◽  
Good Substitute

The cassava peel has been investigated as a good source of energy for various categories of livestock and it has been reported as a good substitute for maize for all classes of pigs.International Livestock Research Institute (ILRI) has transformed fresh cassava peels intohigh quality, safe and hygienic livestock feed, known as High Quality Cassava Peel®. HighQuality Cassava Peel® was produced by sorting, grating, pressing, sieving and drying offresh cassava peels. Sorting of the fresh (harvested the same day) cassava peels was done by removal of the stumps, large sized woody tubers and other foreign materials before grating, to gradually reduce the particle size, ensure rapid dewatering, drying and easy handling of the sorted peels. Next is the pressing of the grated peels in woven bags using a hydraulic jack and wooden planks. The resultant cassava peel cake after pressing around 30- 35% moisture had shelf life of 5- 7 days. The pressed cassava peel cake was re-grated to loosen it into a free flowing material that can be subjected to sieving to separate the fine mash (lower fiber, high energy content) from the coarse mash (higher fiber, lower energy content). The resultant fine or coarse mash was further dried by toasting or sun-drying to a moisture level of 10-12%. The final product with 10–12% moisture content was bagged and stored safely for 4- 6 months without any spoilage. Proximate analysis of the HQCP® further clarified its quality over that of other processed cassava peels. Series of trials conducted have proved High Quality Cassava Peel as a good substitute for significant portion of maize in the diet of growing and weaned pigs without any adverse effect on the performance and blood parameters determined in each of the studies. The results of the studies conducted on the utilization of the high quality cassava peel as a substitute for maize in the diet of weaned and growing pigs have shown the efficacy of HQCP® to replace significant quantities of maize in their diet. High Quality Cassava Peel demonstrated potential for replacement of up to 15% of the 40% maize inclusion in the diet of weaned pigs and 30% in the diet of growing pigs with or without direct fed microbial (DFM) supplementation. No significant effect of DFM was noticed in the utilization of HQCP® by both weaned and growing pigs. All the hematological and serum biochemical parameters determined were within the normal range for healthypigs. Based on the outcome of the feeding trials, HQCP® has been proved to replace asubstantial portion of maize in the diet of weaned and growing pigs, thereby bringing about a decrease in the cost of production

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