Use of fish production per unit biomass ratios for measuring the productive capacity of fish habitats

2000 ◽  
Vol 57 (8) ◽  
pp. 1657-1667 ◽  
Author(s):  
R G Randall ◽  
C K Minns
Keyword(s):  
Life History Theory ◽  
Field Studies ◽  
Productivity Index ◽  
Specific Information ◽  
Productive Capacity ◽  
Fish Production ◽  
Size At Maturity ◽  
Eastern Canada ◽  
Habitat Productivity ◽  
Species Specific

Species-specific production rate per unit biomass (P/B, per year) ratios were calculated for 79 freshwater fish species of eastern Canada. P/B (per year) ratios were calculated using two methods, which were based on allometry with fish weight-at-maturity and life expectancy, respectively. P/B (per year) values obtained by the two methods were significantly correlated, as expected from life history theory, since the two predictors (longevity, size-at-maturity) were themselves correlated. Species-specific P/B (per year) ratios were also significantly correlated with field observations of P/B from published sources. The estimation of P/B based on allometry with fish size is recommended because of its utility; the predictive equation is P/B (per year) = 2.64Wmat-0.35, where Wmat is weight-at-maturity. Both the coefficient 2.64 and the exponent -0.35 of this equation are provisional and require further validation from field studies of fish production. More accurate estimates of P/B are possible if population-specific information on size-at-maturity or mean size is known. The product of average fish biomass and estimated P/B coefficients (habitat productivity index (HPI) = B × P/B) is a proposed measure of habitat productive capacity.

Electron Microscopy in the Study of Natural Phytoplankton Assemblages

1985 ◽  
Vol 43 ◽  
pp. 620-623
Author(s):  
Linda Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Aquatic Environment ◽  
Size Range ◽  
Physical Parameters ◽  
Specific Information ◽  
Phytoplankton Assemblages ◽  
Phytoplankton Productivity ◽  
Ecosystem Effects ◽  
Time Of Year ◽  
Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

Duplex DNA barcoding allows accurate species determination of morphologically similar limpets (Patella spp.) from non-destructive sampling

2016 ◽  
Vol 97 (7) ◽  
pp. 1479-1482 ◽  
Author(s):  
Thomas J. Ashton ◽  
Meriem Kayoueche-Reeve ◽  
Andrew J. Blight ◽  
Jon Moore ◽  
David M. Paterson
Keyword(s):  
Dna Barcoding ◽  
Species Abundance ◽  
Microscopic Analysis ◽  
Cost Effective ◽  
Field Studies ◽  
Similar Species ◽  
Species Determination ◽  
Destructive Sampling ◽  
Species Specific ◽  
Non Destructive

Accurate discrimination of two morphologically similar species of Patella limpets has been facilitated by using qPCR amplification of species-specific mitochondrial genomic regions. Cost-effective and non-destructive sampling is achieved using a mucus swab and simple sample lysis and dilution to create a PCR template. Results show 100% concurrence with dissection and microscopic analysis, and the technique has been employed successfully in field studies. The use of highly sensitive DNA barcoding techniques such as this hold great potential for improving previously challenging field assessments of species abundance.

scholarly journals Projecting marine fish production and catch potential in Bangladesh in the 21st century under long-term environmental change and management scenarios

2015 ◽  
Vol 73 (5) ◽  
pp. 1357-1369 ◽  
Author(s):  
Jose A. Fernandes ◽  
Susan Kay ◽  
Mostafa A. R. Hossain ◽  
Munir Ahmed ◽  
William W. L. Cheung ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Low Income ◽  
Nutrient Loading ◽  
Global Climate Model ◽  
Productive Capacity ◽  
Fish Production ◽  
Management Scenarios ◽  
Bombay Duck

Abstract The fisheries sector is crucial to the Bangladeshi economy and wellbeing, accounting for 4.4% of national gross domestic product and 22.8% of agriculture sector production, and supplying ca. 60% of the national animal protein intake. Fish is vital to the 16 million Bangladeshis living near the coast, a number that has doubled since the 1980s. Here, we develop and apply tools to project the long-term productive capacity of Bangladesh marine fisheries under climate and fisheries management scenarios, based on downscaling a global climate model, using associated river flow and nutrient loading estimates, projecting high-resolution changes in physical and biochemical ocean properties, and eventually projecting fish production and catch potential under different fishing mortality targets. We place particular interest on Hilsa shad (Tenualosa ilisha), which accounts for ca. 11% of total catches, and Bombay duck (Harpadon nehereus), a low price fish that is the second highest catch in Bangladesh and is highly consumed by low-income communities. It is concluded that the impacts of climate change, under greenhouse emissions scenario A1B, are likely to reduce the potential fish production in the Bangladesh exclusive economic zone by <10%. However, these impacts are larger for the two target species. Under sustainable management practices, we expect Hilsa shad catches to show a minor decline in potential catch by 2030 but a significant (25%) decline by 2060. However, if overexploitation is allowed, catches are projected to fall much further, by almost 95% by 2060, compared with the Business as Usual scenario for the start of the 21st century. For Bombay duck, potential catches by 2060 under sustainable scenarios will produce a decline of <20% compared with current catches. The results demonstrate that management can mitigate or exacerbate the effects of climate change on ecosystem productivity.

scholarly journals Characterization, Virulence, Epidemiology, and Management of Anthracnose in Celery

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1832-1840 ◽  
Author(s):  
Lina M. Rodriguez-Salamanca ◽  
Lina M. Quesada-Ocampo ◽  
Rachel P. Naegele ◽  
Mary K. Hausbeck
Keyword(s):  
Disease Incidence ◽  
Field Studies ◽  
Crop Damage ◽  
Apium Graveolens ◽  
Colletotrichum Acutatum ◽  
Banding Patterns ◽  
Growing Seasons ◽  
Colletotrichum Acutatum Species Complex ◽  
Species Specific ◽  
Disease Pressure

Leaf curling and petiole twisting of celery (Apium graveolens) were observed in several commercial fields in five Michigan counties in 2010 through 2012, causing significant crop damage and loss. Prior to this time, the pathogen Colletotrichum acutatum species complex had not been previously associated with celery in Michigan. In this study, the pathogen’s genotype and phenotype were characterized, the influence of environmental conditions determined, and fungicides tested. Pathogen identification was based on conidial morphology and molecular identification using species-specific primers. Intersimple-sequence repeat (ISSR) banding patterns were similar between C. acutatum isolates from celery (n = 51) and blueberry (n = 1) but different from C. dematium and C. gloeosporioides. Four ISSR primers resulted in 4% polymorphism when tested on isolates from celery. Pathogenicity and virulence of C. acutatum sensu lato isolated from celery (n = 81), tomato (n = 2), and blueberry (n = 1) were evaluated in greenhouse experiments, which revealed differences in virulence among isolates but no significant differences specific to collection year, county, or field. In dew chambers and growth chambers, high temperatures (≥25°C) or long leaf wetness duration (>24 h) increased disease incidence. Twelve fungicides were tested in field studies over two growing seasons to determine their efficacy against celery anthracnose. The fungicides azoxystrobin, pyraclostrobin, mancozeb, and chlorothalonil reduced disease by 27 to 50% compared with the untreated control when disease pressure was moderate.

Fish production and the marine ecosystems of the Scotian Shelf, eastern Canada

1979 ◽  
Vol 54 (2) ◽  
pp. 101-108 ◽  
Author(s):  
E. L. Mills ◽  
R. O. Fournier
Keyword(s):  
Marine Ecosystems ◽  
Fish Production ◽  
Scotian Shelf ◽  
Eastern Canada

Chemical fractionation tests on South African coal sources to obtain species-specific information on ash fusion temperatures (AFT)

Fuel ◽  
2005 ◽  
Vol 84 (14-15) ◽  
pp. 1768-1777 ◽  
Author(s):  
J.C. van Dyk ◽  
L.L. Baxter ◽  
J.H.P. van Heerden ◽  
R.L.J. Coetzer
Keyword(s):  
South African ◽  
Chemical Fractionation ◽  
Specific Information ◽  
Species Specific

scholarly journals Daytime depth and thermal habitat of two sympatric krill species in response to surface salinity variability in the Gulf of St Lawrence, eastern Canada

2013 ◽  
Vol 71 (2) ◽  
pp. 272-281 ◽  
Author(s):  
Stéphane Plourde ◽  
Ian H. McQuinn ◽  
Frédéric Maps ◽  
Jean-François St-Pierre ◽  
Diane Lavoie ◽  
...  
Keyword(s):  
Sympatric Species ◽  
Strong Impact ◽  
Surface Salinity ◽  
Eastern Canada ◽  
Environmental Forcing ◽  
Coastal System ◽  
Thermal Habitat ◽  
Run Off ◽  
Salinity Variability ◽  
Species Specific

Abstract Plourde, S., McQuinn, I. H., Maps, F., St-Pierre, J-F., Lavoie, D., and Joly, P. 2014. Daytime depth and thermal habitat of two sympatric krill species in response to surface salinity variability in the Gulf of St Lawrence, eastern Canada. – ICES Journal of Marine Science, 71: 272–281. We describe the response of acoustically determined weighted mean depth (WMD) of two sympatric species of krill, Thysanoessa raschii and Meganyctiphanes norvegica, to variations in surface salinity during summer in the Gulf of St Lawrence. In this coastal system, non-living particulates and CDOM carried by the freshwater run-off of the St Lawrence River and several large rivers have a strong impact on turbidity and light attenuance in the surface layer. The WMD of T. raschii and M. norvegica were significantly and positively related to surface salinity. However, M. norvegica was found deeper and in warmer water than T. raschii, and the latter had a steeper response to surface salinity. The species-specific relationships between daytime WMD and surface salinity enabled us to estimate both species regional and interannual variations in summertime temperature habitat during a 21-year period (1991–2011). The variability in daytime WMD resulted in significant inter- and intraspecific differences in the temperature experienced by adult krill that may impact development, growth, and reproduction. Our study illustrated the importance of considering species-specific responses to environmental forcing in coupled biophysical models that aim to explore the impacts of environmental variations on krill dynamics.

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