scholarly journals COMPARISONS OF ESTUARINE MANAGEMENT NEEDS OF A TROPICAL PACIFIC MEXICAN HARBOUR AND A TEMPERATE CALIFORNIA HARBOUR

2018 ◽  
Vol 19 ◽  
pp. 21-38 ◽  
Author(s):  
Dorothy F. Soule ◽  
Penny A. Morris ◽  
John D. Soule

Two areas of the eastern Pacific are compared, the southern California wetlands south of Point Conception and Mazatlan, Mexico. The historical development of both areas is important in considering their present biological status. Southern California has been subjected to intensive population growth and urbanization while Mazatlan has remained relatively unchanged. Both areas are compared biologically in regards to the fish population, thermal gradients in the harbors, salinity, nitrate, nitrite and phosphate distributions. The economic importance of the harbors is recognized, however it is essential that measures are taken to restore or retain existing wetlands that are associated with the harbors. The harbors can serve as shelters for various organisms if water quality can either be maintained (as in the case of Mazatlan) or improved, and if input of toxic and excessive nutrients is limited.

<em>Abstract</em>.—Since the 1970s, Pacific lamprey <em>Entosphenus tridentatus</em> (formerly <em>Lampetra tridentata</em>) have been documented in various drainages from coastal Southern California. These collections and observations document a relatively stable population especially in the Santa Clara River from the 1970s to 1990s, followed by a significant decline in numbers since the late 1990s, most abruptly after about 2000. This decline may be steeper than documented since collection efforts have increased in this same period. Pacific lamprey counts taken in downstream migratory steelhead <em>Oncorhynchus mykiss</em> traps were documented by the California Department of Fish and Game in Sespe Creek, a Santa Clara River tributary, in 1983 and 1984. The Highway 126 crossing of Sespe Creek, our sample site, is near this trapping site and was sampled repeatedly with seines in 1981–1988, 1995–1998, and 2005–2007. The most robust Pacific lamprey data set in Southern California is from intermittent annual counts at the Freeman Diversion on the Santa Clara River since 1991. Other localities south of Point Conception have also been sampled intermittently. Since the late 1990s, Pacific lamprey trapped during annual collections has dropped to a few individuals. The past 7 years (2002–2009) of efforts have encountered one ammocoete in lower Sespe Creek and 12 macrothalmia or ammocoetes in the main-stem Santa Clara River through both wet and dry years. Five ammocoetes collected in the lower Ventura River on March 8, 2005 are the only other individuals recorded south of Point Conception in the 2000s. This decline in Pacific lamprey south of Point Conception is not easily explained since many conditions have not changed appreciably in that time. Current and long-standing impacts such as dams and diversions that lack adequate Pacific lamprey passage, extended droughts, frequent high-intensity fires, poor water quality, fluctuating ocean conditions, and predation by nonnative piscivores may be sufficient to explain the decline.


2017 ◽  
Vol 15 (2) ◽  
pp. 207-215
Author(s):  
Nur Afiyah Maizunati ◽  
Mohamad Zaenal Arifin

Ongoing population growth and urbanization can cause pressure on water systems, especially in urban areas. Several previous studies have found evidence of an influence between population and water quality. However, the phenomenon in Indonesia is slightly different, because although population growth has decreased trend, but the acquisition of water quality index still fluctuate in several years. This study aims to determine the significance influence of population on water quality in Indonesia. Data analysis is done through regression of panel data of 33 provinces with fixed effect model, The results showed that the population has a negative influence on water quality in Indonesia. An increase on population by 1,000 people tends to lower the water quality index by an average of 1.13 points (cateris paribus). Population growth control becomes absolute and priority in Indonesia. However, these efforts need to be accompanied by continuous improvement of competence and welfare, so that the social awareness and economic capacity of each population are increased in order to achieve a better maintenance on the quality of the environment.


2016 ◽  
Vol 15 (4) ◽  
pp. 11-22
Author(s):  
H M Ashashree ◽  
H A Sayeswara ◽  
K L Naik ◽  
N Kumara Swamy ◽  
Nafeesa Begum

Fresh water wetlands are fragile ecosystems, which are fast deterioring and shrinking due to manmade activities. The fish composition of Huchharayanakere of Shikaripura was studied for a period of twelve months from January to December 2015. The icthyo-faunal diversity of this pond confirmed the occurrence of 13 species of fishes belonging to 5 families. The family Cyprinidae represented by 9 species. Families Anabantidae, Bagridae, Clupeidae and Notopteridae were represented by only a single species. Simultaneously the physico-chemical condition of the water body revealed that water quality is suitable for fish culture. The study of fish fauna of an aquatic body is useful for planning of fisheries development. The pond needs proper management and utilization of this fish wealth and sustainable steps to monitor and conserve the fish health. The present study revealed that Huchharayanakere of Shikaripura harbors wide varieties of fish with economic importance in local and global trade. The study will provide future strategies for development and fish conservation.


2022 ◽  
Vol 14 (2) ◽  
pp. 667
Author(s):  
Andrés Estrada-Rivera ◽  
Alfonso Díaz Fonseca ◽  
Samuel Treviño Mora ◽  
Wendy Argelia García Suastegui ◽  
Edith Chávez Bravo ◽  
...  

Population growth, poorly planned industrial development and uncontrolled production processes have left a significant footprint of environmental deterioration in the Alto Atoyac watershed. In this study, we propose using the integrated pollution index (PI) to characterize the temporary variations in surface water quality during the rapid urbanization process in the municipalities of San Martín Texmelucán (SMT) and Tepetitla de Lardizabal (TL), in the states of Puebla and Tlaxcala, between 1985 and 2020. We assessed the correlation between the population growth rate and the water quality parameters according to the Water Quality Index (ICA). The contribution of each polluting substance to the PI was determined. The industry database was created and the increase in population and industry, and their densities, were estimated. The results indicated that the temporal pattern of surface water quality is determined by the level of urbanization. The water integrated pollution index (WPI) increased with the passage of time in all the localities: SLG 0.0 to 25.0; SMTL 25.0 to 29.0; SRT 4.0 to 29.0; VA 6.0 to 30.0; T 3.5 to 24.0 and SMA 4.0 to 27.0 from 2010 to 2020, respectively. The correlation coefficients between the five parameters (BOD5, COD, CF, TU and TSS) in the six localities were positive with the population. The values that showed a higher correlation with the population were: SLG (FC 0.86), SMTL (BOD5 0.61, COD 0.89, TSS 0.64) and SRT (TU 0.83), corresponding to highly polluted localities, which generates complex and severe environmental implications due to the unsustainable management of water resources. Achieving the sustainability of water in the watershed is a challenge that should be shared between society and state. This type of research can be a useful tool in making environmental management decisions.


2018 ◽  
Vol 7 (3) ◽  
pp. 14 ◽  
Author(s):  
Joseph Kapuku Bwapwa

Water shortage in South Africa is a mixture of many factors: limited and highly polluted watercourses, low rainfall, fast growing population and high evaporation rates. Many studies on watercourses have shown a decline on quality due to the ongoing pollution caused by urbanization, mining, industry, power generation, afforestation and agriculture. Given the current forecasts based on population growth versus the country’s limited water resources, it is unlikely to keep existing patterns regarding the use of water and the discharge of wastes. Predictions are also indicating that pollutants will continue to accumulate in freshwater resources independently of the population growth in South Africa. Issues associated with water quality can turn out to be worsened with environmental devastating consequences. For instance, in the agricultural sector it may lead to a drop in yields and quality for fruits and crops followed by soil contamination. It can harmfully affect the population and aquatic health. Furthermore, water quality deterioration can affect the costs related to purification processes resulting in an increased price of clean water. Human induced activities causing salinization, eutrophication, acidification, presence of pathogens in watercourses, inappropriate waste discharge practices and sewage spills are major causes influencing or deteriorating water quality in South Africa. 


1937 ◽  
Vol 28 (2) ◽  
pp. 181-183 ◽  
Author(s):  
Richard H. Le Pelley

A number of species of this genus of Encyrtid parasites are known to be, and others are suspected to be, secondary parasites ; but apparently the complete life-history has not been observed in any one case. As the genus has an almost world-wide distribution and is doubtless of considerable economic importance, the following observations made in Southern California in part of 1935 and 1936 are recorded.


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