Coastal Lagoon (coastal + lagoon)

Distribution by Scientific Domains


Selected Abstracts


Red-gartered Coot Fulica armillata feeding on the grapsid crab Cyrtograpsus angulatus: advantages and disadvantages of an unusual food resource

IBIS, Issue 1 2008
GERMÁN O. GARCÍA
The behaviour of Red-gartered Coots feeding on an unusual food source was examined at Mar Chiquita Coastal Lagoon, Argentina. The grapsid crab Cyrtograpsus angulatus made up all observed prey items, and 61% were small. Both handling and foraging duration increased with the size of captured crabs, but foraging efficiency decreased. Crab availability affected both the dive duration of the Coots and their foraging decisions with regard to prey-size selection. Two species of gull were observed kleptoparasitizing Coots, especially when the Coot was handling medium or large crabs. Feeding by Coots on Cyrtograpsus angulatus has not been previously documented and may be a feeding innovation. Our estimations suggest that Coots were foraging optimally, since smaller crabs were more energetically profitable. [source]


Effects of Submerged Aquatic Vegetation on Macrozoobenthos in a Coastal Lagoon of the Southwestern Atlantic

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 1 2007
Rafael Arocena
Abstract The freshwater-dominated part of Rocha coastal lagoon recently experienced sudden colonization by submerged aquatic vegetation (SAV). Macrophytes may be beneficial or detrimental for the zoobenthos, and both assemblages may in turn affect the food availability for birds and fishes. With the aim of evaluating the effect of SAV on water conditions and on the composition, abundance and diversity of macrozoobenthos, vegetated areas (V, up to 500 g DW m,2) were compared with vegetation-free areas (N). The benthic abundance was higher in V (up to 5000 ind m,2) than in N (up to 2200 ind m,2). Species richness and abundance of amphipods, gastropods and chironomids were also higher at V compared with N. Conversely, the abundance of Tanais stanfordi (Crustacea), Erodona mactroides (Bivalvia) and Laeonereis culveri (Polychaeta), and the Shannon diversity were higher at N. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Variability of Organic Matter Processing in a Mediterranean Coastal Lagoon

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5-6 2004
Margarita Menéndez
Abstract The spatial variability of plant organic matter processing was studied experimentally in a shallow coastal lagoon (Tancada lagoon, average depth: 37 cm, area: 1.8 km2) in the Ebro River Delta (NE Spain). To determine the effect of hydrology and sediment characteristics on plant organic matter processing, leaves of Phragmites australis at the end of its vegetative cycle and whole plants of Ruppia cirrhosa(Petagna) Grande, just abscised, were enclosed in litter bags. Two different mesh sizes (100 ,m and 2 mm) were used to study the effect of macroinvertebrates on decomposition. The bags were placed in the water column and approximately 15 cm above the sediment at 6 different locations in the lagoon. The experiment was performed twice, in autumn-winter and spring-summer. The effect of macroinvertebrates on decomposition rate was not significant in Tancada lagoon. Breakdown rates showed spatial differences only in spring-summer. In the autumn-winter experiment, the effect of strong wind masked the effects of environmental variables and hydrology on decomposition rate. In the spring-summer experiment, characterised by high stability of the water column, dissolved inorganic nitrogen (DIN) concentration in the water column and organic matter in the sediment were the main factors determining the variability of organic matter processing. A positive relationship was calculated between P. australis decomposition rate and dissolved inorganic nitrogen in spring-summer (r2 = 0.92, p < 0.001). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Temporal Variations of Nutrients, ­Chlorophyll a and Particulate Matter in Three Coastal Lagoons of Amvrakikos Gulf (Ionian Sea, Greece)

MARINE ECOLOGY, Issue 3 2001
Konstantinos A. Kormas
Abstract. The temporal variations of nutrients, chlorophyll a (chl a), suspended particulate matter (SPM) and particulate organic carbon (POC) were measured over 12 months in three shallow coastal brackish water lagoons of the Amvrakikos Gulf, Ionian Sea. Two of the lagoons, Tsoukalio and Rodia, are interconnected but separated from Logarou by a narrow strip of land. Logarou has a better water exchange with the sea as indicated by the higher salinity and dissolved oxygen concentrations and the smaller variation of the above-mentioned parameters. Nitrate concentrations were largely the same in the three lagoons and higher than in the Amvrakikos Gulf. Phosphate concentrations in Logarou exceeded by far those of Tsoukalio/Rodia; the increased phosphate levels recorded in January caused an extended phytoplankton bloom with chl a concentrations higher than in the other two lagoons. Chl a in Tsoukalio was positively correlated with nitrate whereas in the most shallow lagoon, Logarou, it showed a positive correlation with light winds (force 4 and lower), probably caused by resuspension from the sediment. Increased phytoplankton biomass in Logarou coupled with the better water exchange may be related to the higher fish production in this lagoon. [source]


Hydrological connectivity in coastal inland systems: lessons from a Neotropical fish metacommunity

ECOLOGY OF FRESHWATER FISH, Issue 1 2010
P. H. M. De Macedo-Soares
de Macedo-Soares PHM, Petry AC, Farjalla VF, Caramaschi EP. Hydrological connectivity in coastal inland systems: lessons from a Neotropical fish metacommunity. Ecology of Freshwater Fish 2010: 19: 7,18. © 2009 John Wiley & Sons A/S Abstract,,, We assessed the influence of hydrological connectivity in structuring fish communities through seasonal samplings of environmental variables and fishes in a coastal lagoon and associated pools in the Restinga de Jurubatiba National Park, Brazil. Community structure attributes such as species richness, numerical density and biomass, Shannon,Wiener diversity index and evenness were compared between periods of the lowest and highest hydrological connectivity, while the environmental gradient and fish zonation were explored through ordination techniques. The greater hydrological connectivity established in the rainy season promoted the homogenisation of most environmental variables and fish species, which differed markedly from the arrangement observed in the dry season. Despite variation in fish species composition, community attributes showed non-significant differences between the dry and rainy seasons. The patterns of composition and numerical density in pools were strongly influenced by local factors, especially salinity, dissolved oxygen, total phosphorous concentration and water colour in the dry season, in addition to total nitrogen concentration and depth in the rainy season. Comparable to the role played by flood pulses in river-floodplain systems, the hydrological connectivity in these tropical coastal waterbodies seems to strongly influence fish community structure, and, therefore to determine regional biodiversity. [source]


Variation of metallothionein and metal concentrations in the digestive gland of the clam Ruditapes decussatus: Sex and seasonal effects

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2001
Maria A. Serafim
Abstract Metallothionein (MT) and metal (Cd, Cu, and Zn) concentrations were determined in the digestive gland of male and female Ruditapes decussatus. Clams were collected monthly during the period of sexual development, from June to September, at two different sites of a coastal lagoon, the Ria Formosa Lagoon, on the south coast of Portugal. The MT concentrations were determined in the heat-treated cytosolic fraction of the digestive gland of both male and female clams. Total metal (Cd, Cu, and Zn) concentrations in the heat-treated cytosol of the digestive gland were also determined in both sexes. The MT and metal concentrations in the digestive gland were not sex dependent in this species. Therefore, these results suggest that random samples can be used to determine MT and metal concentrations in the digestive gland of R. decussatus. Seasonal and site-specific dependency, however, were detected for MT, Cd, and Cu concentrations. The maximum concentration levels of MT, Cd, and Cu were detected in July and August for both sexes in the same area. Zinc concentrations, however, did not show marked seasonal variations, indicating that this species is able to regulate zinc concentrations. The highest MT concentrations were significantly related to the highest metal concentrations. [source]


A thermodynamic analysis of the anaerobic oxidation of methane in marine sediments

GEOBIOLOGY, Issue 5 2008
D. E. LAROWE
ABSTRACT Anaerobic oxidation of methane (AOM) in anoxic marine sediments is a significant process in the global methane cycle, yet little is known about the role of bulk composition, temperature and pressure on the overall energetics of this process. To better understand the biogeochemistry of AOM, we have calculated and compared the energetics of a number of candidate reactions that microorganisms catalyse during the anaerobic oxidation of methane in (i) a coastal lagoon (Cape Lookout Bight, USA), (ii) the deep Black Sea, and (iii) a deep-sea hydrothermal system (Guaymas basin, Gulf of California). Depending on the metabolic pathway and the environment considered, the amount of energy available to the microorganisms varies from 0 to 184 kJ mol,1. At each site, the reactions in which methane is either oxidized to , acetate or formate are generally only favoured under a narrow range of pressure, temperature and solution composition , particularly under low (10,10 m) hydrogen concentrations. In contrast, the reactions involving sulfate reduction with H2, formate and acetate as electron donors are nearly always thermodynamically favoured. Furthermore, the energetics of ATP synthesis was quantified per mole of methane oxidized. Depending on depth, between 0.4 and 0.6 mol of ATP (mol CH4),1 was produced in the Black Sea sediments. The largest potential productivity of 0.7 mol of ATP (mol CH4),1 was calculated for Guaymas Basin, while the lowest values were predicted at Cape Lookout Bight. The approach used in this study leads to a better understanding of the environmental controls on the energetics of AOM. [source]


Effects of Submerged Aquatic Vegetation on Macrozoobenthos in a Coastal Lagoon of the Southwestern Atlantic

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 1 2007
Rafael Arocena
Abstract The freshwater-dominated part of Rocha coastal lagoon recently experienced sudden colonization by submerged aquatic vegetation (SAV). Macrophytes may be beneficial or detrimental for the zoobenthos, and both assemblages may in turn affect the food availability for birds and fishes. With the aim of evaluating the effect of SAV on water conditions and on the composition, abundance and diversity of macrozoobenthos, vegetated areas (V, up to 500 g DW m,2) were compared with vegetation-free areas (N). The benthic abundance was higher in V (up to 5000 ind m,2) than in N (up to 2200 ind m,2). Species richness and abundance of amphipods, gastropods and chironomids were also higher at V compared with N. Conversely, the abundance of Tanais stanfordi (Crustacea), Erodona mactroides (Bivalvia) and Laeonereis culveri (Polychaeta), and the Shannon diversity were higher at N. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Variability of Organic Matter Processing in a Mediterranean Coastal Lagoon

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5-6 2004
Margarita Menéndez
Abstract The spatial variability of plant organic matter processing was studied experimentally in a shallow coastal lagoon (Tancada lagoon, average depth: 37 cm, area: 1.8 km2) in the Ebro River Delta (NE Spain). To determine the effect of hydrology and sediment characteristics on plant organic matter processing, leaves of Phragmites australis at the end of its vegetative cycle and whole plants of Ruppia cirrhosa(Petagna) Grande, just abscised, were enclosed in litter bags. Two different mesh sizes (100 ,m and 2 mm) were used to study the effect of macroinvertebrates on decomposition. The bags were placed in the water column and approximately 15 cm above the sediment at 6 different locations in the lagoon. The experiment was performed twice, in autumn-winter and spring-summer. The effect of macroinvertebrates on decomposition rate was not significant in Tancada lagoon. Breakdown rates showed spatial differences only in spring-summer. In the autumn-winter experiment, the effect of strong wind masked the effects of environmental variables and hydrology on decomposition rate. In the spring-summer experiment, characterised by high stability of the water column, dissolved inorganic nitrogen (DIN) concentration in the water column and organic matter in the sediment were the main factors determining the variability of organic matter processing. A positive relationship was calculated between P. australis decomposition rate and dissolved inorganic nitrogen in spring-summer (r2 = 0.92, p < 0.001). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Condition of Salaria pavo in the Mar Menor coastal lagoon (SE Iberian Peninsula): potential influence of environmental variables on juveniles

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006
D. Verdiell-Cubedo
Summary The relationship at the local level between fish condition and environmental variables was investigated in Salaria pavo (peacock blenny) juveniles. The relationships between fish condition and 18 environmental variables of shallow areas of the lagoon relating to intra- and interspecific fish interactions, water quality and habitat structure, were analysed. The study revealed that water depth and S. pavo biomass (both related to intraspecific fish interactions) were the ecological variables accounting for most of the variation in the condition of S. pavo juveniles, in this case a negative effect. In this way, the condition of S. pavo juvenile populations may be a good indicator of fish density interactions. [source]


Length,weight relationships for 22 fish species of the Mar Menor coastal lagoon (western Mediterranean Sea)

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2006
D. Verdiell-Cubedo
Summary Length,weight relationships were estimated for 22 species of the Mar Menor coastal lagoon (south-eastern Spain): Lipophrys dalmatinus, Salaria pavo, Callionymus pusillus, Aphanius iberus, Engraulis encrasicolus, Gobius cobitis, G. niger, G. paganellus, Pomatoschistus marmoratus, Symphodus cinereus, Chelon labrosus, Liza aurata, L. ramado, L. saliens, Mugil cephalus, Diplodus puntazzo, D. sargus sargus, Lithognathus mormyrus, Sarpa salpa, Sparus aurata, Hippocampus guttulatus and Syngnathus abaster. The captures were made in shallow areas of the lagoon during 2002,2004. Significant length,weight relationships were found for all species. [source]


Molt and growth of an estuarine crab, Chasmagnathus granulatus (Brachyura: Varunidae), in Mar Chiquita coastal lagoon, Argentina

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2004
T. A. Luppi
Summary Juvenile and adult growth of Chasmagnathus granulatus was studied in the laboratory in terms of molt increment in size (MI) and the intermolt period (IP), comparing data obtained from short-term (STE) and long-term (LTE) laboratory experiments. Crabs in a pre-molt condition were collected for STE, including the entire size range of the species. Larger crabs remained in the laboratory no more than 14 days; the average time to molt was 5.8 ± 3.1 days. We registered the molt of 94 females, 64 males and 34 undifferentiated juveniles and calculated their MI. Moreover, 24 males and four females were reared in the laboratory over 3 years (LTE). Hiatt diagrams did not show sex-specific differences between juveniles of both sexes, but revealed differences between juveniles and adults in each sex as well as between adults of both sexes. The MI decreased gradually with size; this pattern was described with a quadratic model. The IP increased exponentially with size. The presence of regenerating limbs diminished the MI. The abdomen of females reached its final shape and maximum relative width at functional maturity. Growth curves for both sexes were calculated using the von Bertalanffy model, but this model yielded an underestimation of the actual maximum size of this crab. [source]


Reproduction of Micropogonias funieri in a shallow temperate coastal lagoon in the southern Atlantic

JOURNAL OF FISH BIOLOGY, Issue 2002
D. Vizziano
The white croaker Micropogonias furnieri, in the coastal Rocha Lagoon, spawned during 5 months, in late spring and summer. It was eurythermic (gonad growth at 12·5 to 25·5° C, spawning at 20 to 27° C) and mesoxic (living at 5·2 to 9·1 mg l -1). The spawning occurred in brackish (8,18 salinity), basic (c. 8 pH) and oxygenated (c. 8·0 mg l -1) waters. The temperature appeared to be an important environmental factor affecting the timing of reproduction. The size at first maturity (19,20 cm) was 11,12 cm lower than the reported for the Río de la Plata spawning area (Uruguay). Juveniles were observed throughout most of the year suggesting that the lagoon is also a nursery area. In Brazil, M. furnieri spawns in marine areas while in Uruguay it spawns in estuaries. This is the first time that a coastal lagoon of the subtropical and temperate western coast of the South Atlantic Ocean has been shown to be a spawning area of a marine species. [source]


Hypersalinity enhances the production of extracellular polymeric substance (eps) in the texas brown tide alga, aureoumbra lagunensis (PELAGOPHYCEAE)

JOURNAL OF PHYCOLOGY, Issue 1 2000
Hongbin Liu
Laboratory experiments with batch cultures showed that the Texas brown tide alga, Aureoumbra lagunensis Stockwell, DeYoe, Hargraves et Johnson, produced a large amount of extracellular polymeric substance (EPS) that formed an extracellular polysaccharide mucus layer. Both dissolved and particulate carbohydrate and EPS concentrations increased as A. lagunensis cultures progressed from exponential growth phase, through stationary phase, to declining phase. Particulate carbohydrate and EPS concentrations per cell were more than three times higher during the declining phase than that in exponential growth phase, reflecting a large increase in the EPS mucus layer. The amounts of carbohydrate and EPS produced by A. lagunensis were significantly higher under hypersaline conditions. The thicker EPS mucus layer surrounding A. lagunensis cells under hypersaline conditions might be a protective adaptation that permits it to bloom under hypersaline conditions that most other phytoplankton cannot survive. This could be one of the reasons why the Texas brown tide persisted in the Laguna Madre, an often hypersaline coastal lagoon, for 7 years. [source]


High gene flow promotes the genetic homogeneity of the fish goby Pomatoschistus marmoratus (Risso, 1810) from Mar Menor coastal lagoon and adjacent marine waters (Spain)

MARINE ECOLOGY, Issue 2 2010
Carlos Vergara-Chen
Abstract The extreme environmental variability of coastal lagoons suggests that physical and ecological factors could contribute to the genetic divergence among populations occurring in lagoon and open-coast environments. In this study we analysed the genetic variability of lagoon and marine samples of the sand goby, Pomatoschistus marmoratus (Risso, 1810) (Pisces: Gobiidae), on the SW Spain coast. A fragment of mitochondrial DNA control region (570 bp) was sequenced for 196 individuals collected in five localities: Lo Pagan, Los Urrutias and Playa Honda (Mar Menor coastal lagoon), and Veneziola and Mazarrón (Mediterranean Sea). The total haplotype diversity was h = 0.9424 ± 0.0229, and the total nucleotide diversity was , = 0.0108 ± 0.0058. Among-sample genetic differentiation was not significant and small-scale patterns in the distribution of haplotypes were not apparent. Gene flow and dispersal-related life history traits may account for low genetic structure at a small spatial scale. The high genetic diversity found in P. marmoratus increases its potential to adapt to changing conditions of the Mar Menor coastal lagoon. [source]


A dynamical model for characterising seasonality effects on eelgrass plastochron intervals

ANNALS OF APPLIED BIOLOGY, Issue 1 2010
E. Solana-Arellano
The plastochron interval is widely used to calculate age and rates of productivity in many plants, including seagrasses. However, plant responses to changing environmental conditions, including seasonal patterns, can introduce substantial errors in methods for calculating age and rates of growth. We propose a generalised method for characterising seasonal variability in eelgrass plastochron values based on a model that consists of a linear combination of a trend, a seasonality component and a stochastic noise component. The model was validated using data obtained biweekly during 1998,2003 in a Zostera marina meadow in a coastal lagoon in northwestern Baja California. Plastochron intervals exhibited marked interannual and seasonal variability as well as in the timing of plastochron interval (PI) minima and maxima. Correlation analyses indicated that sea surface temperature is a fundamental forcing factor for the plastochron interval, whose local variability is influenced by the onset of ,El Niño' and ,La Niña' events. The proposed model provided reliable interpretations that elicited the existence of seasonal processes which are usually masked by multimodal changes in the plastochron interval. Using successive averages of seasonal PI to describe annual cycles resulted in reliable leaf-growth assessments as well as in better determinations of shoot age than those calculated using a single annual mean. [source]


Natural revegetation of coal fly ash in a highly saline disposal lagoon in Hong Kong

APPLIED VEGETATION SCIENCE, Issue 3 2008
L.M. Chu
Abstract. Question: What is the relationship of the naturally colonizing vegetation and substrate characteristics in fly ash lagoons? Location: West lagoon, Deep Bay, a 13-ha coastal lagoon in Hong Kong in subtropical Southeast Asia. Methods: Vegetation establishment was examined in a coal fly ash lagoon two years after its abandonment to investigate the distribution of vegetation in relationship to the chemical properties of the fly ash in the lagoon. A greenhouse experiment assessed the limits imposed on plant growth in fly ash. Results: The fly ash was saline, slightly alkaline and very poor in organic matter and nitrogen. Ash from bare and vegetated areas differed significantly in their salinity and extractable concentrations of inorganic nitrogen and various metals. Bare ash had a significantly higher conductivity and extractable sodium, aluminum, manganese, potassium, and lead. In total 11 plant species that belonged to seven families were found growing on the fly ash; all species except the shrub Tamarix chinensis were herbaceous. Using discriminant analysis, the most important factors in distinguishing bare and vegetated ashes were conductivity and sodium. Cluster analysis of bare samples gave two distinct groups, one from the periphery of the lagoon, which had lower sodium, conductivity, organic carbon, potassium and copper, and the other from a second group that contained ashes from the central region of the lagoon. Results of the greenhouse experiment showed that the inhibition of plant growth was significantly correlated with the presence of soluble toxic elements in ash. Conclusion: Toxicity and salinity seem to be the major limiting factors to plant establishment in fly ash, and these factors must be ameliorated for the successful reclamation of these fly ash lagoons. [source]


Short-term variation in the ecological status of a Mediterranean coastal lagoon (NE Iberian Peninsula) after a man-made change of hydrological regime

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2008
Anna Badosa
Abstract 1.The Ter Vell (NE Iberian Peninsula) is a eutrophic coastal lagoon that has been mostly flooded by excessive irrigation water during recent decades. During 2001 and 2002 the lagoon was subject to several water management actions, the main consequence of which was a change in the hydrological regime due to drastically reduced irrigation water inputs to the lagoon. 2.In order to comply with the Water Framework Directive, all the management actions in an ecosystem should be focused on protecting and, where necessary, improving its ecological status. 3.The aims of this study were (1) to analyse whether the hydrological change caused by management actions have affected the ecological status of the lagoon, and (2) to discuss the suitability of several physicochemical and biological indicators for the assessment of the ecological status in this kind of coastal ecosystem. 4.After the change in the hydrological regime, a general improvement of the ecological status was observed mainly as a result of the significant decrease in the nitrogen Trophic State Index and in the abundance of rotifer indicative of eutrophy, and in turn by the significant increase in the water quality index QAELS, based on crustaceans and insect assemblages. 5.Contradictory results emerged with regard to some of the indicators used. After the hydrological change, the increase in the phosphorus Trophic State Index was related with the fact that Mediterranean confined coastal ecosystems are typically P-enriched. In contrast with general assumptions, low diversity and richness of the zooplankton and the dominance of a few species have been related with an improvement of the ecological status after the hydrological change, when freshwater inputs were reduced and the lagoon became more confined. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Seasonality of hydrographic variables in a coastal lagoon: Mar Chiquita, Argentina

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2006
Jorge Marcovecchio
Abstract 1.The concentration and distribution of several hydrographical variables from Mar Chiquita coastal lagoon, Argentina, were measured monthly over a year in order to quantify their seasonal variations. Temperature, salinity, inorganic nutrient concentrations (nitrate, nitrite, phosphate, silicate) in the water column, and photosynthetic pigments (chlorophyll a and phaeopigments) in suspended particulate matter (SPM), were measured using internationally standardized analytical methods. 2.Agricultural use of land surrounding the coastal lagoon has been shown to be the main nutrient source, owing to the use of fertilizers for farming and the consequent leaching of the soils by freshwater runoff. 3.Two different hydrographical areas were identified within the coastal lagoon, one showing marine influence and the other dominated by inland influence (due to catchment and freshwater inputs), both with different characteristics and ecological behaviour. 4.The frequent occurrence of phytoplankton blooms has also been identified within the coastal lagoon. There was significant biological production (in terms of chlorophyll a) within the lagoon throughout the year. The lagoon appears to function as a transitional system, opportunistically benefiting from extra nutrient inputs which, together with other environmental conditions, results in a continuous food supply, useful to both marine and estuarine organisms. Consequently the system is important for numerous fish and shellfish species as a nursery area. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Fisheries of two tropical lagoons in Ghana, West Africa

FISHERIES MANAGEMENT & ECOLOGY, Issue 6 2004
H. R. Dankwa
Abstract, The fisheries of two coastal lagoons, Keta and Songor, were studied as part of Ghana Coastal Wetlands Management Project (GCWMP) aimed at sustainable exploitation of wetland resources. Fish samples were obtained with seine nets and cast net as well as from local fishermen. Water quality parameters (pH, dissolved oxygen, temperature and turbidity) were similar in the two lagoons, except for salinity, which was significantly different (P < 0.001). Despite their close geographical proximity, the two lagoons supported different fish assemblages with the blackchin tilapia, Sarotherodon melanotheron Rüppell, and the redchin tilapia, Tilapia guineensis (Bleeker), being the most important commercial fishes in both lagoons. The number of individuals for each species in Songor Lagoon were far more abundant, with densities several orders of magnitude higher than in Keta Lagoon. However, both species were significantly larger (P < 0.01) in the latter [15,121 and 25,157 mm standard length (SL)] than in the former lagoon (30,102 and 15,95 mm SL) for S. melanotheron and T. guineensis respectively. Over-fishing, use of small-size mesh nets, limited mixing of marine and fresh water were some of the factors limiting fish production in both lagoons. [source]


Effects of atmospheric circulation on ice conditions in the southern Baltic coastal lagoons

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 13 2001
Józef Piotr Girjatowicz
Abstract Relationships between atmospheric circulation patterns and ice conditions in the southern Baltic coastal lagoons were explored. Ice data consisted of number of ice days (L) and duration of ice season (S) in the Szczecin Lagoon (off Karnin), the Puck Bay (off Puck) and the Vistula Lagoon (off Krasnoflotskoye) from 1950/1951 to 1989/1990. Atmospheric circulation patterns for the period studied were extracted from Lity,ski's ,Calendar of atmospheric circulation types' developed at the Institute of Meteorology and Water Management (IMWM). A circulation pattern was identified by three numerical parameters: the zonal circulation index, the meridional circulation index, both pertaining to a zone delimited by coordinates 40,60°N, 0,35°E, and the surface pressure index for Warsaw. The number of days with individual atmospheric circulation patterns occurring from October to March was calculated. Subsequently, the selected patterns were combined by wind direction sectors and several month-long periods that most closely correlated with ice conditions. The highest linear correlation coefficients (r>0.8) were obtained for the relationship between the number of days with winds from the east from December to February and December to March and the winter number of ice days (L). Somewhat higher were multiple correlation coefficients with winds from the east and west as circulation type predictors. Slightly lower correlation coefficients for the sectors and circulation periods mentioned were obtained for the duration of the ice season (S), although some of the coefficients were significant even at the probability level of ,=0.01. Higher correlation coefficients were obtained for correlations involving ,cold' circulation patterns (sector NE+E+SE winds) and ice conditions than for those involving ,warm' patterns (sector SW+W+NW). Copyright © 2001 Royal Meteorological Society [source]


Recruitment and growth of two small-bodied resident fish species (Gobiidae and Atherinidae) in oligohaline, seasonally open lagoons

JOURNAL OF FISH BIOLOGY, Issue 6 2010
P. G. Close
Spatio-temporal recruitment patterns, growth and survival of the Swan River goby Pseudogobius olorum and western hardyhead Leptatherina wallacei are described from two small, coastal lagoons on the south coast of Western Australia. In these lagoons, estuarine salinity dynamics were relatively stable over much of the autumn,spring period when freshwater inputs from rivers were reduced and there was no oceanic connection. Preflexion and flexion stages of both fish species contributed strongly to population size structure in downstream reaches, whereas upstream reaches were dominated by postflexion larvae and juvenile stages. Spawning of both species was protracted and largely asynchronous, although the episodic presence of stronger preflexion and flexion cohorts suggested some synchronized spawning had occurred. Comparison with estuarine conditions over this period provided evidence that synchronized spawning may be related to temperature and salinity variations from a combination of freshwater inputs and periods of marine exchange. Uninterrupted growth and the progression of cohorts through to juvenile stages were consistent with the generally stable estuarine conditions. Larval and juvenile stages of both species were also tolerant of abrupt changes in salinity and temperature, which occurred due to a non-seasonal oceanic connection. These findings were consistent with the euryhaline nature of adults of both species. [source]


Fish communities in two environmentally different estuarine systems of Mexico

JOURNAL OF FISH BIOLOGY, Issue 2002
A. Raz-Guzman
Mexico has two main types of coasts, an Amero-trailing-edge coast along the Gulf of Mexico and a collision coast along the Pacific, each of which determine the characteristics of their coastal lagoons. The lagoons along the Gulf of Mexico are extensive, tropical and rich in seagrass beds and mangroves, and among these Laguna Madre has 84 species of fishes. In contrast, the lagoons along the Pacific are small, closed, mostly oligohaline and usually lack seagrass beds, and among these Laguna Salinas del Padre has 19 species of fishes. This marked difference in species richness, in turn, has a direct effect on the size and value of the fisheries, as these are regional in the first case and local and seasonal in the second. [source]


High gene flow promotes the genetic homogeneity of the fish goby Pomatoschistus marmoratus (Risso, 1810) from Mar Menor coastal lagoon and adjacent marine waters (Spain)

MARINE ECOLOGY, Issue 2 2010
Carlos Vergara-Chen
Abstract The extreme environmental variability of coastal lagoons suggests that physical and ecological factors could contribute to the genetic divergence among populations occurring in lagoon and open-coast environments. In this study we analysed the genetic variability of lagoon and marine samples of the sand goby, Pomatoschistus marmoratus (Risso, 1810) (Pisces: Gobiidae), on the SW Spain coast. A fragment of mitochondrial DNA control region (570 bp) was sequenced for 196 individuals collected in five localities: Lo Pagan, Los Urrutias and Playa Honda (Mar Menor coastal lagoon), and Veneziola and Mazarrón (Mediterranean Sea). The total haplotype diversity was h = 0.9424 ± 0.0229, and the total nucleotide diversity was , = 0.0108 ± 0.0058. Among-sample genetic differentiation was not significant and small-scale patterns in the distribution of haplotypes were not apparent. Gene flow and dispersal-related life history traits may account for low genetic structure at a small spatial scale. The high genetic diversity found in P. marmoratus increases its potential to adapt to changing conditions of the Mar Menor coastal lagoon. [source]


Notes on coastal lagoon typology in the light of the EU Water Framework Directive: Italy as a case study

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2006
Davide Tagliapietra
Abstract 1.The European Water Framework Directive (WFD) requires that Member States differentiate the transitional water bodies into types. 2.WFD assigns coastal lagoons to two different water categories, ,transitional waters' and ,coastal waters' on the basis of freshwater influence. 3.The main physical factors that contribute to the genesis and characterization of coastal lagoons are coastal typology, tidal range and climate. 4.Italian lagoons are presented as an example of how these physical factors can be used in coastal lagoon characterization and typology. On this basis, a clear distinction of Italian lagoons into two main groups is possible: Northern Adriatic and Mediterranean. 5.Large lagoons can be profitably subdivided into a hierarchical system of sub-basins facilitating both the comparison of parts of the same lagoon and the comparison between different lagoons. 6.The basins are consistent water bodies that can be used as managerial units for environmental conservation, species protection and wise use of resources. Copyright © 2006 John Wiley & Sons, Ltd. [source]