Brackish Water Systems Research Articles

Growth performance, blood health, and antioxidant status of freshwater carp under brackish water rearing system: Sustainable aquaculture approach in arid and semi-arid conditions

Global warming, water salinization, and increased anthropogenic usage of freshwater sources have had severe effects on water sources and aquaculture practices, which is consequently putting pressure on aquatic fauna and fish production. Hence, brackish water can be used as an alternative and sustainable approach to meet the increasing food requirements. Four groups with triplicates were designed to evaluate the impact of brackish water on Cirrhinus mrigala (n = 100) for 180 days; T0: control group (freshwater), T1: (5.45 ppt salinity), T2: (8.45 ppt salinity) and T3 (12.45 ppt salinity). Little behavioural alterations and normal feeding were observed in all experimental groups as compared to control group, except group T3. Survival rate was 100 % in all groups excluding group T3, which had shown 88 % survival rate (P < 0.05), while mean weight gain and length gain were observed better with low FCR in T1 and T2 groups (P < 0.05) but best growth rate observed at 5 ppt salinity level. Significant reduction in haemoglobin (Hb), hematocrit (HCT), red blood cells (RBCs) and increase in white blood cells (WBCs) and platelets (PLTs) was observed in group T3 compared to other experimental groups (P < 0.05). ALT, AST, ALP, urea, creatinine, and triglycerides, exhibited significant changes in T3 group after 180 days (P < 0.05). Erythrocytes had shown morphological alterations as; micronuclei, notching, blebbing, pear-shaped nuclei and spherocytes in T3 group. Significant increase in DNA damage in various tissues had indicated potential genotoxic impact of highly saline brackish water. Oxidative stress markers were increased significantly and antioxidants reduced (P < 0.05) at high salinity level brackish water (T3) until 180 days. In conclusion, C. mrigala can potentially grow well in brackish water system at 5 ppt salinity whereas, rise in salinity level (12 ppt) is detrimental to freshwater fish health and growth.

The Implications of Atlantic Salmon (Salmo salar L.) Fatty Acid Profiles for Their Thiamine Status.

Thiamine deficiency is an ongoing issue across the Northern Hemisphere, causing reproductive failure in multiple salmonid populations. In the Baltic Sea, a large brackish water system in northern Europe, previous research has suggested that this deficiency is associated with lipid-rich diets with a high proportion of docosahexaenoic acid (DHA, 22:6n-3). The mechanism proposed is that a diet abundant in highly unsaturated fatty acids, such as DHA, depletes thiamine as an antioxidant defense in adult salmonids, rather than allocating thiamine to the offspring. In light of this existing hypothesis, we here explore the relationship between diet history and the related fatty acid (FA), profiles, and thiamine status of Atlantic salmon (Salmo salar L.) in three systems: the Baltic Sea, the North Atlantic Ocean, and Lake Vänern. Atlantic salmon inhabiting each system is known to have unique feeding histories and thiamine status. Our results showed that despite extensive sampling effort and distinct FA profiles, indicative of their diverse diets, there were no correlations between any FAs, including DHA, and the thiamine status of these populations. This finding does not support the above-mentioned hypothesis that diets rich in easily oxidized FAs would lead to lower thiamine concentrations in salmon tissues. Additionally, we found that changes in the salmon FA profiles throughout their life cycle are consistent for both low-thiamine populations from the Baltic Sea and medium-thiamine populations from North Atlantic Ocean, suggesting that these changes might not be involved in thiamine deficiency development.

Influence of in situ Biofloc Production on Bio Growth Performance, Physiological Immune Response, Digestive Enzyme Activity, Nutrient Composition and Disease Resistance of Etroplus suratensis

Backgroud: The present experiment was conducted to investigate the effects of insitu jaggery based biofloc on biogrowth performance, physiological immuno response, digestive enzyme activity, nutrient composition and disease resistance of Etroplus suratensis. Method: The fingerlings of pearlspot, E. suratensis with an average body weight of 5.67±0.08 g was stocked at the rate of 150/m3 in treatment and control system. The insitu biofloc was produced in 2.4 ton capacity outdoor tanks using jaggery as carbon source at two different C: N ratio of viz, 10: 1 (B1) and 20:1 (B2), where clear brackishwater system and without carbon source as control. Result: The levels of ammonia nitrogen, nitrite–nitrogen and nitrate–nitrogen were reduced in the insitu biofloc compared to control while TSS and TS were increased significantly in all insitu biofloc compared to control. The physiological immuno responses such as Respiratory burst test, Myeloperoxidase, serum lysozyme and antioxidant enzymes activity Superoxide dismutase and catalase were found to be significantly higher in B2 at end of the trial. Stress parameters glucose and cortisol were significantly lower in jaggery based biofloc system especially in (B2) C: N 20:1 compared to control. The fishes from the jaggery based biofloc groups possessed significantly (P less than 0.05) higher immune status as compared to control. The digestive enzymes activity such as amylase protease and lipase, of fish was higher in biofloc treatment and lower in control. Compare to control the nutrient composition of E. suratensis was significantly higher in the treatment groups. Moreover, jaggery based insitu fishes showed the lower cumulative mortality rate and Enhanced relative levels of protectio after experimental challenge with A. hydrophila compared to control.

Assessing Impacts of Flood Diversion on the Ecosystem of Brackish-Water Lakes through Simulation-Optimization Model

This study develops and evaluates a simulation-optimization approach to mitigate the environmental impacts of freshwater pulses in brackish-water lakes whilst maximizing flood diversion benefits. Lake Pontchartrain, located downstream of the Mississippi River, Mississippi, United States, is a brackish-water ecosystem threatened by reducing salinity concentrations due to freshwater pulses from the flood diversion project on the Mississippi River. An adaptive neuro-fuzzy-inference-system-based model was developed as a data-driven model for simulating salinity distribution at a representative station of Lake Pontchartrain. Then, the data-driven model was used as the simulator in the optimization system. Both single-objective and multi-objective particle swarm optimizations were used to find the optimal solutions. Results show that the data-driven model is robust at simulating the salinity time series in the brackish-water ecosystem of Lake Pontchartrain. The Nash–Sutcliffe efficiency index of the data-driven model between measured and modelled salinity is 0.85, which means the model is reliable for applying in further simulations. The proposed optimal solutions for the environmental management of the lake indicate that because of the magnitude of the volume of freshwater released, environmental impacts at this location cannot be optimized through varying the timing and volume of the releases. This work presents a novel contribution to science through developing an optimization framework for mitigating the impacts of flood management on changes in salinity in brackish-water systems.

Adsorption Kinetics of Cadmium and Lead by Biochars in Single- and Bisolute Brackish Water Systems

Adsorption Kinetics of Cadmium and Lead by Biochars in Single- and Bisolute Brackish Water Systems

Geochemical Modeling of Changes in Storage Rock Environments at CO2 Injection Sites

Geochemical modeling in TOUGHREACT code was used to simulate chemical processes in CO2–rock–brackish water systems in a pilot research environment of CO2 storage in the Brodske area (Czech Republic). Models studied mineralogical changes in rock samples resulting from acidification of the aqueous phase caused by the dissolution of pressurized supercritical CO2. Rock samples of the reservoir horizon and cement from the grouting of an injection borehole were considered, and the water phase represented the mineralized groundwater. The aim of the study was to characterize the influence of CO2 in the geological structure on mineralogical rock changes and to predict gas distribution through the rocks bearing brackish water. The most important chemical processes are dissolution of carbonates and clay minerals during the injection of CO2 into the structure, as the increase in porosity in the structure affects the sequestration capacity of the reservoir rock. In the CO2–cement–brackish water system, the models confirm the rapid dissolution of portlandite and its replacement with calcite. The CSH gel is also dissolved, and silica gel appears. The porosity of the cement decreases. Further studies on such a cement slurry are needed to prevent the possibility of mechanical damage to the integrity of the borehole.

Joint use of biological traits, diversity and biotic indices to assess the ecological quality status of a Mediterranean transitional system

In the present study, we tested the effectiveness of biological trait analysis (BTA) as an ecological indicator in support of the assessment of the Ecological Quality Status (EQS) of a Mediterranean transitional system by commonly used macrobenthic assemblage diversity (e.g. H’ and Margalef) and biotic (BENTIX, M−AMBI and M−bAMBI) indices. Ten biological traits describing morphological, behavioral and life history characteristics were considered for the analysis of the functional structure of macrobenthos. As a test study, a historical dataset obtained from the Cabras lagoon (Sardinia, Italy) comprising a riverine site, the lagoonal main body, a confined pond, a seaward creek and a marine channel connected to the Gulf of Oristano was analyzed. Our results showed clear spatial changes in macrobenthic density, number of species and diversity indices along the riverine-lagoon-sea gradient, which were well reflected in the EQS values based on M−AMBI and to a lesser extent on M−bAMBI. The abundance-based functional diversity was significantly related to the structure and taxonomic diversity of the benthic community. Similarly, the Community-level Weighted Mean test computed with abundance data, rather than with biomass data, supported major evidence for differences in the ecological conditions of the different study sites. In particular, all riverine, lagoonal and confined stations had poor or bad EQS, indicating unstable and warning conditions in this Mediterranean transitional water body. Overall, the BTA approach appeared to be a very promising method in reporting the expected environmental and biotic variability in the Cabras lagoon system and in supporting the EQS assessment by M−AMBI. We conclude that an in-depth knowledge of the benthic communities in terms of both taxonomic and functional aspects is an indispensable basic tool for understanding the variability of the brackish-water systems and for properly assessing their environmental quality.

Acclimation of Nodularia spumigena CCY9414 to inorganic phosphate limitation - Identification of the P-limitation stimulon via RNA-seq.

Nodularia spumigena is a toxic, filamentous cyanobacterium capable of fixing atmospheric N2, which is often dominating cyanobacterial bloom events in the Baltic Sea and other brackish water systems worldwide. Increasing phosphate limitation has been considered as one environmental factor promoting cyanobacterial mass developments. In the present study, we analyzed the response of N. spumigena strain CCY9414 toward strong phosphate limitation. Growth of the strain was diminished under P-deplete conditions; however, filaments contained more polyphosphate under P-deplete compared to P-replete conditions. Using RNA-seq, gene expression was compared in N. spumigena CCY9414 after 7 and 14 days in P-deplete and P-replete conditions, respectively. After 7 days, 112 genes were significantly up-regulated in P-deplete filaments, among them was a high proportion of genes encoding proteins related to P-homeostasis such as transport systems for different P species. Many of these genes became also up-regulated after 14 days compared to 7 days in filaments grown under P-replete conditions, which was consistent with the almost complete consumption of dissolved P in these cultures after 14 days. In addition to genes directly related to P starvation, genes encoding proteins for bioactive compound synthesis, gas vesicles formation, or sugar catabolism were stimulated under P-deplete conditions. Collectively, our data describe an experimentally validated P-stimulon in N. spumigena CCY9414 and provide the indication that severe P limitation could indeed support bloom formation by this filamentous strain.

Managing reservoir fisheries: a critical look at reservoir physical environment

This short note follows a discussion on a study that assessed reservoir fisheries and ecosystem-based management approaches in Ghana. The main objectives of the study were to develop an understanding of how differences in reservoir morphometry and physicochemical characteristics influence ecosystem structures and fisheries productivity. This involved reviewing and updating empirical models for reservoir harvest estimations, relating morphometric characteristics of the reservoirs to fish production, assessing the exploitation levels and stock status of the reservoirs’ target species and providing a holistic description of the reservoirs’ biological interactions through a food web modelling approach. To manage reservoirs and associated riverine environments for the benefit of fish and fisheries, reservoirs' status and contribution to capture fisheries production have to be evaluated and addressed. Furthermore, the technical criteria and measures germane to assessment frameworks must be improved. Protecting and enhancing the physical environment of reservoirs for fish production requires considerations of ecosystem perspectives, optimal morphometric characteristics, duration of reservoir filling and development and prevention of critical nutrient enrichment. For enhancing Ghana's fish production, development strategies should focus on fisheries and aquaculture production in rivers, floodplains, lakes, reservoirs, and brackish water systems. Research, policy, and capacity-building issues related to developing these production systems must be addressed adequately. Moreover, to fully exploit their potential, the management requirements of the individual reservoir systems need to be assessed and appropriate regimes implemented with stakeholders.

Impact of Stocking Density on the Survival, Growth and Injury of Narrow-Clawed Crayfish (Pontastacus leptodactylus) Reared in a Flowing Brackish Water System

The crayfish population dramatically declined in most lakes and dams in Türkiye; hence, crayfish culture is a possible option to increase the supply. This study aimed to determine the effects of stocking density on the growth performance and survival of newly-hatched third instars of narrow-clawed crayfish (Pontastacus leptodactylus) in a flowing brackish water system. The third instars were randomly stocked in nine tanks (area: 1.7 ) for 120 days with three densities of 10, 50, and 100 crayfish/. The results indicated that the stocking density significantly affected the growth performance, survival rate, proportion of the cheliped injury, biomass, length distribution, and feed conversion ratio (FCR). The mean final weights and total lengths were 2.27, 1.40, and 1.08 g and 4.83, 3.73 and 3.51 cm according to the densities, respectively. The highest stocking density increased the total biomass yield and proportion of the cheliped injury but reduced the survival, growth, molting frequency and regeneration of the appendage. The survival (86.3%) and specific growth rate (1.16 cm/day) in the 10 individuals/ group were significantly higher than the other groups. The cheliped injury was also found to be the lowest in the 10 individual/ group (p<0.05). Our study results showed that significant differences in FCR value were observed at different stocking densities. In summary, higher stocking density at the end of this study increased the frequency and severity of aggressive interactions of crayfish, limiting molting frequency and growth performance. A density of 10-50 crayfish/ is recommended for better growth parameters while 100 crayfish/ is suggested for higher biomass yield.

Health Complaints, Mental Status and Quality of Life among the Aquaculture Workers: A Cross-Sectional Study in Northern Region of Peninsular Malaysia.

Aquaculture is seen as an essential food-producing sector for improving global food security and nutrition indices. This cross-sectional study examined the health complaints and mental health status of aquaculture workers, as well as their relationship with quality of life, with respect to the brackish water and freshwater aquaculture cultivation system in Penang, Malaysia. The workers’ health complaints were collected, and mental health status was evaluated as means of depression, anxiety, stress and self-esteem. Self-perceived quality of life was assessed using a structured questionnaire. This study involved the participation of 88 brackish water (84.6%) and 16 freshwater (15.4%) aquaculture workers. A total of 72.7% of the brackish water aquaculture workers were aged beyond 50 years old and had worked within five years (77.3%) in the aquaculture industry. Both brackish water and freshwater cultivation workers were confronted with fatigue, pain and insomnia. Up to 48%, 40.4%, 26% and 24% of them were facing depression, anxiety, stress and low self-esteem, respectively. A total of 3.4% of the brackish water aquaculture workers were having bad quality of life. The complaints of neck/shoulder/arm pain (F = 13.963; p < 0.001), back pain (F = 10.974; p < 0.01), hand/wrist pain (F = 8.041; p < 0.01), knee/hip pain (F = 12.910; p < 0.01) and insomnia (F = 10.936; p < 0.01) were correlated with bad quality of life among the workers. For mental health status, self-esteem (F = 4.157; p < 0.05) was found to be negatively correlated with quality of life scores. The results outlined the concerning level of health complaints and psychological distress among the aquaculture workers. The study emphasized the importance of developing an appropriate occupational health strategy in the aquaculture industry. Longitudinal investigations aimed to explore the effects of psychological distress on employment productivity among the high-risk workers are warranted.

Impact of extreme events on the transformation of hydrological characteristics of Asia's largest brackish water system, Chilika Lake.

The earth is experiencing the impact of climate change due to global warming. Lake ecosystems are no exception and are expected to cope with the consequences of extreme climatic events (hereafter ECE), such as storms, floods, and droughts. These events have significant potential to alter the hydrological characteristics (HC) influencing the physical, chemical, and biological behavior of lake ecosystems. Considering such ecosystem's high-value services and benefits, it is the need of the hour to monitor and evaluate the impact of ECE on lake ecosystems. The second-largest brackish water system in the world, Chilika Lake, situated at the shore of the Bay of Bengal (BoB), has encountered a total of 1306 tropical cyclonic storms in the last 131years. Since most tropical cyclones lead to heavy floods, this could be devastating for the ecosystem and its services. Hence, in order to bridge the knowledge gap, the present study was carried out to understand its impact, based on the available field data of more than two decades (1999 to 2020) and historical records of ECE and HC since 1840 and 1915 respectively from the literature. The study revealed that the ECE attributed to short-term changes in HC which were reflected through an immediate change in trophic state index (TSI, indicator of lake health) and trophic switchover (net autotrophic to heterotrophic) between net sink and source of carbon dioxide (CO2) in specific regions. This study showed that both the ECE as well as a human intervention (opening of the new mouth) had an integrated role in the maintenance of HC within the lake as indicated by the variability of salinity level which is the lifeblood of the Chilika. Major ECE factors which controlled the salinity in Chilika were freshwater input through cyclone-induced flash flooding and seawater exchange through varying mouth conditions, i.e., opening of the new mouth, shifting, and widening of existing mouths due to cyclone impacts. The impact of the cyclone-induced flash flood was sustained for a couple of months to years depending on the magnitudes. As evidenced from the historical data available for ECEs, respective mouth variability, and salinity regime, ECE was found to maintain the salinity regime of the lake in the long run. Since the hydrological characteristics are found to be maintained through ECE as well as human intervention, the Chilika Lake recorded a substantial increase in fishery, seagrasses, Irrawaddy dolphins, migratory birds, and reduction in weed infestation. This study highlights the importance of historical data collection through a continuous systematic lake monitoring program which would enable understanding the ecosystem functioning and behavior with ECE-induced changing environmental conditions which is also a key component for formulating a sustainable management action plan for lake ecosystems around the globe.

Imprints of COVID-19 lockdowns on total petroleum hydrocarbon levels in Asia's largest brackish water lagoon

India successfully executed one of the strictest lockdowns in the world during the height of the COVID-19 pandemic in early 2020, which provided unique opportunities to analyze the second-largest populous country's anthropogenic footprint on its natural systems. India's first Ramsar site and the world's second-largest brackish water system Chilika lagoon experienced a substantial decline (64%) in the total petroleum hydrocarbon (TPHC) level in water, which was attributed to the massive declines or, at times, an abrupt complete halt of motorized boat operations for fishing and tourism. Using the TPHC values during the lockdown period, our study recommends a TPHC baseline threshold of 2.02 μg L−1 and 0.91 μg g−1 for Chilika waters and sediment, respectively. These baseline values can be used to quantify oil pollution and to formulate policy and management action plans for Chilika lagoon as well as for other similar ecosystems by local environmental agencies.

Explorative Study of Aquaponics Systems in Indonesia

Aquaponics is the combined cultivation of fish in aquaculture systems and plants in hydroponic systems. This study aimed to explore and evaluate new aquaponics system designs in Jakarta, Indonesia, in terms of water and nutrient efficiency, and/or profitability. In total, one brackish water system with barramundi and tomato (BW) and three freshwater systems with Nile tilapia, rice, and duckweed (FW + DW), Nile tilapia and rice (FW − DW), and Nile tilapia and tomato (FW-tomato) were investigated using dynamic mathematical models. The results showed an increase of N, P, and water use efficiency by 10%, 18%, and 31%, respectively, in FW-tomato compare to FW − DW. Meanwhile, FW + DW only slightly increased the efficiency but worsened the already negative net present value (NPV) of FW − DW due to the high land prices. The BW system had similar water and nutrient efficiency to FW-tomato, but lower NPV. Profit of the BW and FW-tomato becomes comparable if the hydroponic area in the BW system can be expanded by 35%, or the selling price of tomato or fish in the BW can be increased by 20%. Given the expected growth of both the production of tomatoes and aquaculture in Indonesia, there is potential for further introduction of aquaponics systems in Indonesia.

Long-term variation of CO2 flux and the controlling factors in Asia’s largest brackish water system, Chilika Lake

Long-term variation of CO2 flux and the controlling factors in Asia’s largest brackish water system, Chilika Lake

Phytoplankton of the Curonian Lagoon as a New Interesting Source for Bioactive Natural Products. Special Impact on Cyanobacterial Metabolites.

The bioprospecting of marine and brackish water systems has increased during the last decades. In this respect, microalgae, including cyanobacteria, and their metabolites are one of the most widely explored resources. Most of the bioactive compounds are isolated from ex situ cultures of microorganisms; however, analysis of field samples could also supply valuable information about the metabolic and biotechnological potential of microalgae communities. In this work, the activity of phytoplankton samples from the Curonian Lagoon was studied. The samples were active against antibiotic resistant clinical and environmental bacterial strains as well as against serine proteases and T47D human breast adenocarcinoma cells. No significant effect was found on Daphnia magna. In addition, using LC-MS/MS, we documented the diversity of metabolites present in field samples. A list of 117 detected cyanopeptides was presented. Cyanopeptolins constituted the largest class of cyanopeptides. As complex bloom samples were analyzed, no link between the observed activity and a specific sample component can be established. However, the results of the study showed a biotechnological potential of natural products from the Curonian Lagoon.

Exploring sustainable aquaculture development using a nutrition-sensitive approach

Micronutrient deficiencies constitute a pressing public health concern, especially in developing countries. As a dense source of bioavailable nutrients, aquatic foods can help alleviate such deficiencies. Developing aquaculture that provides critical micronutrients without sacrificing the underlying environmental resources that support these food production systems is therefore essential. Here, we address these dual challenges by optimizing nutrient supply while constraining the environmental impacts from aquaculture. Using life cycle assessment and nutritional data from Indonesia, a top aquaculture producer, we sought to identify aquaculture systems that increase micronutrient supplies and reduce environmental impacts (e.g., habitat destruction, freshwater pollution, and greenhouse gas emissions). Aquaculture systems in Indonesia vary more by environmental impacts (e.g. three order of magnitude for fresh water usage) than by nutritional differences (approximately ± 50% differences from mean relative nutritional score). Nutritional-environmental tradeoffs exist, with no single system offering a complete nutrition-environment win–win. We also find that previously proposed future aquaculture paths suboptimally balance nutritional and environmental impacts. Instead, we identify optimized aquaculture production scenarios for 2030 with nutrient per gram densities 105–320% that of business-as-usual production and with environmental impacts as low as 25% of those of business-as-usual. In these scenarios Pangasius fish (Pangasius hypophthalmus) ponds prove desirable due to their low environmental impacts, but average relative nutrient score. While the environmental impacts of the three analyzed brackish water systems range from average to high compared to other aquaculture systems, their nutritional attributes render them necessary when maximizing all nutrients except vitamin A. Common carp (Cyprinus carpio) ponds also proved essential in maximizing zinc and omega n-3, while Tilapia (Oreochromis niloticus) cages were necessary in optimizing the production of calcium and vitamin A. These optimal aquaculture strategies also reduce business-as-usual demand for wild fish-based feed by 0–30% and mangrove expansion by 0–75% with no additional expansion into inland open waters and freshwater ponds. As aquaculture production expands globally, optimization presents a powerful opportunity to reduce malnutrition rates at reduced environmental impacts. The proposed reorientation promotes UN sustainable development goals 2 (zero hunger), 3 (health), 13 (climate action) and 14 (life under water) and requires concerted and targeted policy changes.

Energetic, economic and environmental assessment of zero liquid discharge (ZLD) brackish water and seawater desalination systems

The discharge of brine (saline wastewater) from brackish water and seawater desalination plants poses a major threat to the natural environment. This research study presents an energetic, economic and environmental assessment of zero liquid discharge (ZLD) desalination systems in the Eastern Mediterranean. Two scenarios are considered: (i) ZLD brackish water and (ii) ZLD seawater systems, both aimed at producing saleable freshwater and mixed solid salt. Results showed that the energy consumption in scenario 1 (9.48 kWh/m3) is 2.38 times lower than in scenario 2 (22.55 kWh/m3) due to the 7 times lower feed salinity. The differentiation in energy demands is also translated to costs since scenario 2 (US$1.04/m3) is 1.24 times more expensive than scenario 1 (US$0.84/m3). Both scenarios are 3.18 times cheaper than the disposal method of the evaporation pond, while they are in the same cost range as the land application and deep-well injection. Whether only freshwater is sold or both freshwater and mixed solid salt are sold, both scenarios are profitable as the profit ranges from US$215.05/day to US$302.55/day. Concerning CO2 emissions, scenario 1 (5.91–6.45 kg CO2/m3) has lower values than scenario 2 (14.05–15.33 kg CO2/m3) as the energy demanded in scenario 1 is significantly lower.

Occurrence and length weight relationship of Indo-Pacific mugilid Chelon carinatus (Valenciennes 1836) in four river estuaries of Turkey

Occurence and length-weight (LWR) relationships of four populations of Chelon carinatus in brackishwater systems of Mediterranean coast of Turkey were reported. A non-indigenous fish species, C. carinatus were captured between November 2014 and June 2017 in Ceyhan, Seyhan, Göksu and Manavgat river estuaries. A total of 127 individuals, ranging in size between 11.8 and 20.8 cm total length, 19.0 and 113.6 g weight, were examined. The length–weight relationship for all individuals was described by the following parameters: a = 0.0076; b = 3.1708 and r2 = 0.93. The results of the current length-weight relationship study show that there is significant difference from the isometric b (3.0) value for all these populations. The length-weight relationships from all localities were reported here for the first time.

Interaction between Styrofoam and Microalgae Spirulina platensis in Brackish Water System

Styrofoam is a thermoplastic with special characteristics; it is an efficient insulator, is extremely lightweight, absorbs trauma, is bacteria resistant, and is an ideal packaging material, compared to other thermoplastics. The aim of this study was to analyze the interaction between Styrofoam and S. platensis. The study examined the growth of S. platensis under Styrofoam stress, changes in Styrofoam functional groups, and their interactions. The research method was culture carried out in brackish water (12 mg/L salinity) for 30 days. S. platensis yields were tested by FTIR and SEM-EDX and Styrofoam samples by FTIR. The results showed the highest growth rate of S. platensis in cultures treated with 150 mg Styrofoam that is 0.0401 day−1. FTIR analysis shows that there has been a change in the functional group on Styrofoam. At a wavelength of 3400–3200 cm−1 corresponds to the alcohol group and there was an open cyclic chain shown by the appearance of a wavelength at 1680–1600 cm−1 assignment to alkene. SEM-EDX test results show that Styrofoam can be a resource of nutrition, especially carbon for S. platensis to photosynthesize. Increased carbon content of 24.56% occurred in culture, meanwhile, Styrofoam is able to damage S. platensis cells.