Yield Properties and Structure of Boreal Percid Communities in Ontario

1977 ◽  
Vol 34 (10) ◽  
pp. 1613-1625 ◽  
Author(s):  
G. F. Adams ◽  
C. H. Olver
Keyword(s):  
Total Yield ◽  
Fishing Effort ◽  
Productive Capacity ◽  
Lake Productivity ◽  
Net Community Production ◽  
Yield Data ◽  
Northern Ontario ◽  
Fish Yield ◽  
Theoretical Yield ◽  
Morphoedaphic Index

A synoptic review of yield data for 70 northern Ontario lakes from 1917 to 1973 showed that percids mainly walleye (Stizostedion vitreum vitreum) constituted about one-third, by weight, of the total fish yield. This relationship, which was independent of fishing effort, lake size, and lake productivity, is considered to be an emergent property of this type of fish community and represents a degree of homeostasis within the community under exploitation. The relation of percid yield to theoretical yield (based on the morphoedaphic index — MEI) reflected organizational structure and suggested the existence of a community (percid) component within the MEI, and from this we recommend upper limits of percid harvest for boreal percid lakes.Most (83%) of the 70 lakes had an average total yield of less than 2.5 kg∙ha−1∙yr−1, 53% (37 lakes) yielding less than one-half of the theoretical yield (average 3.4 kg∙ha−1∙yr−1). Long-term average yields exceeded the theoretical maximums in only 11 lakes. Mesotrophic to slightly eutrophic waters appeared as optimum for percid yields.Inferences from the data suggest an unexploited boreal percid community is characterized by high community stability and low net community production with resiliency low because of the low productive capacity of the waters. A yield index (RYI), which was assumed to reflect both effort and vulnerability to exploitation, showed that fishing intensity tended to be higher on the smaller, less productive lakes in this study. Key words: Percidae, Stizostedion, community ecology, yield properties, management implications

Water quality, fishing effort and fish yield in lakes

1992 ◽  
Vol 15 (1-2) ◽  
pp. 105-119 ◽  
Author(s):  
Esa Ranta ◽  
Kai Lindström ◽  
Kalervo Salojärvi
Keyword(s):  
Water Quality ◽  
Fishing Effort ◽  
Fish Yield

Relationships of Fish Yield to Lake Phytoplankton Standing Crop, Production, and Morphoedaphic Factors

1977 ◽  
Vol 34 (12) ◽  
pp. 2271-2279 ◽  
Author(s):  
Ray T. Oglesby
Keyword(s):  
Primary Production ◽  
Standing Crop ◽  
Crop Production ◽  
Fishery Management ◽  
Cold Water ◽  
Phytoplankton Production ◽  
Fish Yield ◽  
Morphoedaphic Index ◽  
Intensively Managed ◽  
Predicted Values

Fish yield is related to annual primary production, summer phytoplankton standing crop, and the morphoedaphic index for lakes representing a wide variety of typologies by a series of models in the form of log-log regressions. Tentative boundary conditions are established by which lakes inappropriate to the models can be excluded. Confidence intervals for predicted values about the mean are given for the fish yield–phytoplankton standing crop regression. From this relation, potential yields for the lakes studied are reduced from a range of 10,000 to one of 25-fold. Efficiencies with which carbon is transferred from primary production to fish yield vary by 2 to 3 orders of magnitude and are highest for small, intensively managed ponds and lowest for large, deep, cold-water lakes. Models based upon fish yield as a function of phytoplankton production or standing crop are inherently more accurate and subject to fewer exceptions than are those related to morphoedaphic factors. The former appear to be capable of substantial refinement but even in their present state might be employed to make useful predictions for groups of lakes. A suggested supplement to existing approaches in fishery management involves the following sequence: (1) use of expectation-variability diagrams to obtain an overview of the problem, (2) selection of an appropriate model or models to predict yield, (3) prediction of a range of yields, and (4) implementation of regulations proved successful for other lakes in the same yield category. Key words: fish, lakes, phytoplankton, morphoedaphic index, fishery management

Can growth be used as a surrogate measure of walleye (Sander vitreus) abundance change?

2005 ◽  
Vol 62 (9) ◽  
pp. 2159-2168 ◽  
Author(s):  
Greg G Sass ◽  
James F Kitchell
Keyword(s):  
Positive Influence ◽  
Growth Patterns ◽  
Sander Vitreus ◽  
Adult Density ◽  
Lake Productivity ◽  
Regional Patterns ◽  
Density Dependent ◽  
Morphoedaphic Index ◽  
Improved Model ◽  
Surrogate Measures

We examined several models to determine the relative contributions of density-dependent and density-independent factors on walleye (Sander vitreus) growth in the ceded territory of Wisconsin from 1990 to 1999. We then used independent data from 2000 to determine how well each model predicted walleye growth and examined several models to determine if growth could be used to predict density. Adult density best predicted the mean size of age-3 males ( [Formula: see text]3m) and age-5 females ( [Formula: see text]5f). Density-independent measures of pH, the morphoedaphic index, maximum depth, and conductance had a positive influence on growth, while adult density negatively affected growth. The solely density-dependent models predicted [Formula: see text]3m and [Formula: see text]5f poorly in 2000. The addition of density-independent factors improved model predictions of [Formula: see text]3m and [Formula: see text]5f. Walleye growth did not predict adult walleye densities. Regional patterns in walleye growth were correlated with surrogate measures of lake productivity and to a lesser extent adult density. Density dependence had a relatively weak affect on growth patterns, suggesting that growth cannot be used as a surrogate method for monitoring abundance change.

TRICKLE IRRIGATION OF DAY-NEUTRAL STRAWBERRIES USING EVAPOTRANSPIRATION.

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 686B-686
Author(s):  
Gail R. Nonnecke ◽  
Henry G. Taber
Keyword(s):  
Total Yield ◽  
Growing Season ◽  
Trickle Irrigation ◽  
Yield Data ◽  
Proper Management ◽  
Irrigation Treatments

The purpose of this project was to investigate the use of evapotranspiration (ET) as a guideline for trickle irrigation timing in field-grown day-neutral `Tristar' strawberry. Proper management of trickle irrigation would allow optimum yields and quality with minimum water inputs. A randomized complete block field design with four replications was used at the ISU Horticulture Station in central Iowa. Irrigation treatments were based on % of ET and number of applications per week. The four treatments included: 30, 60, and 90 % of ET applied once per week (1X) and 30% of ET applied 3 times per week (3X). Total yield data (kg of fruit per season) indicated the 30% of ET (3X) treated plants yielded 15% more fruit than the 30% of ET (1X) plants. Berry number was 14% greater from plants receiving the 30% of ET (3X) treatment than from those receiving the 30% of ET (1X) treatment. Average berry weights for the entire growing season were similar among all treatments.

Fish Production Correlated with Primary Productivity, not the Morphoedaphic Index

1990 ◽  
Vol 47 (10) ◽  
pp. 1929-1936 ◽  
Author(s):  
John A. Downing ◽  
Céline Plante ◽  
Sophie Lalonde
Keyword(s):  
Standing Stock ◽  
Phytoplankton Production ◽  
Phosphorus Concentration ◽  
Regression Equations ◽  
Fish Production ◽  
Oligotrophic Lakes ◽  
Yield Data ◽  
Total Phosphorus Concentration ◽  
Wide Range ◽  
Morphoedaphic Index

Estimates of the biological production of entire lake fish communities were collected from the published literature on lakes covering a wide range of geographic areas and trophic status. Correlation analysis shows that fish production is uncorrected with the morphoedaphic index (p > 0.05) but closely correlated with annual phytoplankton production (r2 = 0.79), mean total phosphorus concentration (r2 = 0.67), and annual average fish standing stock (r2 = 0.67). Empirically derived regression equations are presented and compared with previous models based on catch and yield data. Analysis of these equations suggests that conversion of phytoplankton into fish production is 100 times more efficient in oligotrophic lakes than hyper-eutrophic ones, but that a much lower fraction of fish production can be channeled to sustainable yield in oligotrophic lakes. Sustained yields were frequently as little as 10% of the annual community fish production.

The Morphoedaphic Index, a Fish Yield Estimator — Review and Evaluation

1974 ◽  
Vol 31 (5) ◽  
pp. 663-688 ◽  
Author(s):  
R. A. Ryder ◽  
S. R. Kerr ◽  
K. H. Loftus ◽  
H. A. Regier
Keyword(s):  
Ecological Theory ◽  
Total Dissolved Solids ◽  
Future Application ◽  
Commercial Fish ◽  
Fish Yield ◽  
Climatic Regions ◽  
Changing Environments ◽  
Morphoedaphic Index ◽  
North Temperate Lakes ◽  
Fish Yields

The morphoedaphic index (MEI), a fish yield estimator, was historically reviewed and evaluated. Background papers leading to the development of the MEI were discussed, as well as more recent advances. The MEI was defined and its criteria for use examined. The significance of its components — total dissolved solids and mean depth — were explained. The MEI was compared with related models developed by other workers. The global range of the MEI was outlined as well as restrictions on its use. Sustained fish yields at different MEI values for various climatic regions were predicted. Several special applications of the MEI were described, including: prediction of angling yield in north-temperate lakes; prediction of commercial fish yield on a newly created reservoir; indicator of ecological stresses and changing environments; and contrasting responses to cultural eutrophication in the littoral and profundal zones of lakes. The implications of the MEI for ecological theory were explored, and its potential for future application in management was outlined.

scholarly journals The biology of the greater weever (Trachinus draco) in the commercial fishery of the Kattegat

2004 ◽  
Vol 61 (6) ◽  
pp. 933-943 ◽  
Author(s):  
Ole Bagge
Keyword(s):  
Total Yield ◽  
Total Mortality ◽  
Fishing Effort ◽  
Commercial Fishery ◽  
Current Yield ◽  
Or Management ◽  
By Catch ◽  
Stock Abundance

Abstract The scarce published literature on greater weever in western and northwestern European waters is reviewed and synthesized, along with a summary of a Danish investigation in the Kattegat for the years 1961–1973. Distribution, growth, mortality, migration, fecundity, abundance, and stock abundance in relation to the directed local commercial fishery are described. The greater weever has not been and still is not in any way protected by legislation or management, although it moves little, grows slowly, has high catchability, and has been exposed to high total mortality. Since the mid-1980s, directed fishing effort has declined, likely as a consequence of the decreasing catches, and because the effort applied through poundnets, which earlier produced about 40% of the total yield, has for other reasons almost halted. Total landings concomitantly decreased, and the current yield is now only by-catch from trawlers and from two or three 40-ft vessels occasionally directly targeting the species.

scholarly journals Early yield of five cacao families at three locations in Puerto Rico

1969 ◽  
Vol 82 (3-4) ◽  
pp. 163-171 ◽  
Author(s):  
Héber Irizarry ◽  
Edmundo Rivera
Keyword(s):  
Central America ◽  
Total Yield ◽  
Total Production ◽  
Intensive Management ◽  
Yield Data ◽  
Individual Tree ◽  
Evaluation Period ◽  
The Individual ◽  
Theobroma Cacao L ◽  
Hurricane Hugo

Five families of Theobroma cacao L. between three and eleven years of age were evaluated for yield at Gurabo, Corozal and Yabucoa. Parents involved in the combination of the families were such well-known clones as 'Pound-7', 'Scavina (SCA)-6', 'Scavina-12', and IMC, EET and UF selections which have been widely used to produce controlled-pollinated seed in Central America and elsewhere. Eight months after transplant, the temporary shade provided by plantains was removed, and the trees were grown under full sunlight and intensive management. Between 1986 and 1993 individual tree yield data were obtained. In September 1989, hurricane Hugo destroyed the Yabucoa experiment but the evaluation continued at Gurabo and Corozal until December 1993. At the termination of the first four-year evaluation period (1988 to 1989), families EET-400 x SCA-12 and SCA-6 x EET-62 were significantly superior yielders at Gurabo with an average total production of 5,538 kg/ha of dry beans. None of the families maintained superiority at Corozal and Yabucoa. The average total yield for all families was 5,950 and 5,225 kg/ha at Corozal and Yabucoa, respectively. The individual tree yield data showed that regardless of location only 2 or 3% of the trees within a family were high yielders and accounted for more than 60% of the total family production. At the termination of the eight-year evaluation period (1986- 1993), families EET-400 x SCA-12 and SCA-6 x EET-62 maintained their superior yielding ability at Gurabo, with an average total production of 14,368 kg/ha. All families performed similarly at Corozal with an average total production of 14,930 kg/ha.

scholarly journals Pengendalian penyakit hawar (lateblight) pada Kentang (Solanum tuberosum L.) melalui penerapan solarisasi tanah dan aplikasi agen hayati Trichoderma harzianum

2017 ◽  
Vol 1 (2) ◽  
pp. 31
Author(s):  
Eirene Brugman ◽  
Endang Dwi Purbajanti ◽  
Eny Fuskhah
Keyword(s):  
Soil Temperature ◽  
Trichoderma Harzianum ◽  
Plant Protection ◽  
Solanum Tuberosum L ◽  
Total Yield ◽  
Biological Agent ◽  
Soil Solarization ◽  
Intensity Level ◽  
Yield Data ◽  
Pathogen Attack

The purpose of the research was to assess the effectiveness of soil solarization and biological agent Trichoderma harzianum application in controlling lateblight disease caused by Phytophthora infestans on potato. The experiment was assigned in a split plot design with soil solarization as main plot and the density of Trichoderma harzianum as sub-plot. Soil solarization treatment consisted of solarization (A1) and non-solarization (B1). Density of Trichoderma harzianum used is B1(control)= 0g, B2 = 10g (107 cfu/l), B3 = 20g (2 x 108 cfu/l), B4 = 30g (3 x 108 cfu/l) and B5 = 40 g (4 x 108 cfu/l). Soil solarization treatment is carried out by using transparent polyethylene sheets with a thickness of 45 µm. Parameters measured were soil temperature, intensity level of pathogen attack, the rate of infection and total yield. Data were subjected to ANOVA and followed by LSD test. Soil solarization for 4 weeks increase the soil temperature by 7,6oC and significantly increase the production of potato by 14.28%. Application of biological agent Trichoderma harzianum on level B4 30g (3 x 108 cfu /L) gives the best results in reducing the the intensity level of pathogen attack by 69.13% and the rate of disease infection into 1,012 unit/day. The results of this research may provide benefical information in the future for plant protection activities.   Keywords : P.infestans, Trichoderma harzianum, soil solarization, potato

scholarly journals Genotype × Environment effects on morphological and productive components of sweet potato (Ipomoea batatasL.)

2021 ◽  
Vol 17 (5) ◽  
pp. 7-15
Author(s):  
Sindi Elen Senff ◽  
Viviane de Fátima Milcheski ◽  
Ana Caroline Basniak Konkol ◽  
Ana Carolina da Costa Lara Fioreze
Keyword(s):  
Sweet Potato ◽  
Block Design ◽  
Total Yield ◽  
Root Diameter ◽  
Root Weight ◽  
Marketable Yield ◽  
Yield Data ◽  
Growing Seasons ◽  
Environment Effects ◽  
Randomized Block Design

Sweet potato (Ipomoea batatasL.) is a crop with high market demands because of its well-known health benefits. Limited use of improved clones reduces the crop’s income potential. Plant breeding programs seek to selectgenotypes with good results in a variety of environments by evaluating the interaction effects of genotypes and environments. This study aimed to assess Clone × Growing season effects on morphological and productive parameters of sweet potato clones grown in the municipality of Curitibanos, Santa Catarina, Brazil, in 2016/2017 and 2017/2018. The following clones were evaluated: Brazlândia Rosada, BRS Amélia, Beauregard, BrazlândiaRoxa, and BRS Rubissol. A randomized block design with three replications was used to investigate root length, root diameter, mean root weight, total root number, number of marketable roots, total yield, and marketable yield. Data were subjected to one-way and two-way analysis of variance. Beauregard afforded the largest number of marketable roots and was stable in both growing seasons. Beauregard, Brazlândia Roxa, and Brazlândia Rosada differed in total number of roots between growing seasons. There were no significant differences between growing seasons in mean root weight; BRS Amélia afforded a higher mean root weight than Brazlândia Rosada. Beauregard did not differ in total or marketable yield between growing seasons and provided higher yields than the other clones. BRS Rubissol and Beauregard were found to be the most promising for sweet potato cultivation under the environmental conditions of Curitibanos.

Sign in / Sign up

Export Citation Format

Share Document