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Silva, E. I. L.; Amarasinghe, U.S.; Silva, S. S. De; Nissanka, C.; Schiemer, F.

doi:10.1023/a:1021310119462

Cited by 3 publications

(3 citation statements)

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“…Consequently, decisions on water management frequently do not take into account the impact on fish and fisheries. Due to the diverse nature of biological productivity of reservoirs across the country (Silva et al 2002), empirical yield predictive models are useful for yield prediction in the reservoir fisheries. Regier, Ita and Kudhongania (1988) mentioned the value of empirical approaches which treat complexities in reservoirs more holistically instead of data reduction approaches which might lead to oversimplification.…”

Section: Discussionmentioning

confidence: 99%

“…In the present analysis, there were two sources of data, i.e., the data collected from ten selected irrigation reservoirs in the Kala oya river basin of Sri Lanka (Fig. 1) from June 2013 to February 2016, and those reported by Nissanka, Amarasinghe and De Silva (2000) and Amarasinghe, De Silva and Nissanka (2002) for several irrigation reservoirs of Sri Lanka. Reservoirs selected from the Kala oya river basin in the present study were Angamuwa, Balaluwewa, Dewahuwa, Ibbankatuwa, Kalawewa, Kandalama, Katiyawa, Rajanganaya, Siyambalangamuwa and Usgala Siyambalangamuwa.…”

Section: Methodsmentioning

confidence: 99%

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Empirical yield predictive models for the fisheries of irrigation reservoirs in Sri Lanka

Nadarajah

Wijenayake

Amarasinghe

2018

Sri Lanka J. Aquat.

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As fisheries production in reservoirs of most countries is a secondary use, challenges for improved management of fisheries should be addressed by building partnership between fisheries and other interested groups such as agriculture concerned with water management. Attempts were therefore made to develop empirical fish yield predictive models in ten irrigation reservoirs of Sri Lanka incorporating morphological, edaphic and hydrological parameters together with fishing intensity, with a view to investigating their influence on fish yields. Reservoir fish yield was found to be significantly correlated with two formulations of morpho-edaphic index (i.e., conductivity in μS cm-1 /mean depth in m [MEIc] and alkalinity in m. equiv. l-1)/mean depth in m [MEIa]), and a relative reservoir level fluctuation index (RRLF), defined as the mean amplitude of the annual reservoir level fluctuations divided by the mean depth of the reservoir. Both MEIc and MEIa also had significant positive ln-ln relationships with RRWL, indicating that RRWL can be used as an independent variable in reservoir fish yield prediction. Reservoir fish yield was also related to fishing intensity (FI in boat-days ha-1 , yr-1) conforming to a ln-linear regression model (p<0.05). When MEIa, MEIc and RRWL were used as predctor variables together with FI, reservoir fish yield (FY) was multiply correlated as follows: Ln FY = 3.245 + 0.327 Ln MEIa + 0.023 FI (R 2 = 0.355; p< 0.01) Ln FY = 3.403 + 0.249 Ln MEIc + 0.019 FI (R 2 = 0.369; p< 0.01) Ln FY = 1.330 + 0.650 Ln RRWL + 0.016 FI (R 2 = 0.593; p< 0.001) The empirical yield predictive model based on RRWL and FI as independent variables was more robust than those based on MEIa and MEIc, and the former has significant management implications because RRWL can be manipulated by irrigation authorities whereas control of FI is under the jurisdiction of fisheries authorities. Hence, through an effective dialogue between irrigation and fisheries authorities, there is a considerable potential to optimize fish yields in irrigation reservoirs of Sri Lanka.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Empirical yield predictive models for the fisheries of irrigation reservoirs in Sri Lanka

Nadarajah

Wijenayake

Amarasinghe

2018

Sri Lanka J. Aquat.

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“…For example, embroidery could be a pastime for the richest housewives but mean the livelihood of some poor women. 71 In this context, the Inquisition accused Luzia Barbalha Bezerra of practicing Judaism. According to the testimonials in her trial, she was poor.…”

Section: Women In the Captaincy Of Paraíba: Documents And Intersectional Approaches In Legal Historymentioning

confidence: 99%

Women in the Captaincy of Paraíba: a Legal History Approach to the Sources of Colonial Brazil

Silva

2021

Fundamental Questions

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This chapter lays the groundwork for a legal history perspective for the history of women in colonial Paraíba, a captaincy of the Portuguese Empire in Northeast Brazil, based on an analysis of normativities. Using documents about women in colonial Paraíba sourced from Portuguese and Brazilian archives from the sixteenth century until the early nineteenth century, I question the mainstream understanding of women in the colonial period by arguing that there were many differences among women. I demonstrate that women in colonial Paraíba were far from static categorizations and prove that women's legal history in colonial Brazil cannot be understood without connecting gender, religion, condition and status.

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Oligotrophication trend of Lake Ziway, Ethiopia

Beneberu

Mengistou

2011

SEJS

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Some ecological changes have been noted in Lake Ziway since the 1980s, such as lowering of the lake level, introduction and dominance of the catfish Clarias gariepinus in the fishery (53%) and establishment of cladocerans such as Daphnia barbata and Ceriodaphnia cornuta. This prompted us to study the phytoplankton biomass to see whether these changes were cascaded through the trophic food chain of Lake Ziway. The dynamics of some chemical and biological parameters were studied in two littoral and one offshore sites in the lake from November 2003 to August 2004. Nutrients showed temporal as well as spatial variations. Nitrate increased in the offshore whereas soluble reactive phosphate (SRP) was high in littoral sites (20-380 µg/L), indicating anthropogenic impacts. Mean phytoplankton biomass was high at the offshore (43.85 mg Chl a m-3) and almost similar at the littoral sites (Mean values 33.73 and 33.68 mg Chl a m-3), but much lower than values reported earlier. Hourly rate of integral photosynthesis (∑A) ranged from 57.4-726 mg O 2 m-2 h-1 at the offshore and 95-300 mg O 2 m-2 h-1 at littoral sites, respectively. Biomass-specific rate of photosynthetic production at light saturation, (photosynthetic capacity, Φmax) ranged from 5.06-28.8 mg O 2 (mg Chl a)-1 h-1 , slightly higher than values reported in the 1980s (9.6-22.5), due to depressed algal biomass. Although nutrients have increased, phytoplankton biomass (as Chl a) has decreased over the last two decades, possibly due to heavy grazing by zooplankton and introduced fish. If this continues for some time, Lake Ziway will head towards oligotrophication, instead of eutrophication, as speculated by previous workers.

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Untitled

Cited by 3 publications

References 27 publications

Empirical yield predictive models for the fisheries of irrigation reservoirs in Sri Lanka

Empirical yield predictive models for the fisheries of irrigation reservoirs in Sri Lanka

Women in the Captaincy of Paraíba: a Legal History Approach to the Sources of Colonial Brazil

Oligotrophication trend of Lake Ziway, Ethiopia

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