scholarly journals Influence of Seascape on Coastal Lagoon Fisheries: the Role of Habitat Mosaic in the Venice Lagoon

2021 ◽  
Author(s):  
Luca Scapin ◽  
Matteo Zucchetta ◽  
Fabio Pranovi ◽  
Piero Franzoi
Keyword(s):  
Water Quality ◽  
Coastal Lagoons ◽  
Spatial Scales ◽  
Venice Lagoon ◽  
Habitat Characteristics ◽  
Artisanal Fishery ◽  
Sediment Grain Size ◽  
Northern Adriatic ◽  
Broad Scale

AbstractFisheries are a staple human activity supported by coastal lagoons. Together with water quality and trophic status, lagoon morphology is acknowledged as one of the main ecological drivers of fishery yields; however, the role of lagoon seascape structure is still poorly understood. This paper investigates how morphological variables, habitat distribution and seascape diversity and complexity affect yields of artisanal fishery performed with fyke nets in the Venice Lagoon (northern Adriatic Sea, Italy). Two spatial scales were considered in the analysis, with water quality parameters (temperature, salinity, dissolved oxygen, turbidity, water residence times, N, P and chlorophyll-a concentrations) being measured at a fine, fyke-net scale and morphological (average bottom elevation and sediment grain size) and habitat features (habitat proportion, diversity and complexity) being measured at a broader, seascape scale. Generalised linear mixed models were employed to model 8 years of nekton and green crab catches, disentangling the role of broad-scale morphology and seascape from that of fine-scale water quality. Broad-scale variables clearly influenced fishery target species. Among them, lagoon residents were associated with specific morphological and habitat characteristics, while marine migrants showed a stronger link with overall habitat diversity and complexity. This evidence emphasises how artisanal fishery in the Venice Lagoon relies on the conservation of morphological and habitat heterogeneity. Moreover, it highlights how habitat restoration performed at the seascape level should also be taken into account, in addition to controlling hydrology and water quality, when managing fishery resources in coastal lagoons.

Mangroves as Fish Habitat

2015 ◽  
Keyword(s):  
Water Quality ◽  
Particle Size ◽  
Species Richness ◽  
Fish Species ◽  
Fish Community ◽  
Spatial Scales ◽  
Quality Parameters ◽  
Habitat Characteristics ◽  
Fish Community Structure ◽  
Simultaneous Assessment

<em>Abstract</em>.—Three adjacent tidal creek systems (Page, Kemps, and Broad creeks) on Cape Eleuthera, The Bahamas were studied to quantify the variation in fish community structure and habitat characteristics over small (<5 km) spatial scales. Snorkeling transects were used to census the fish community on a summer new moon during slack high tide and involved the simultaneous assessment of each creek and each zone within the creek (i.e., mouth, middle, and upper) replicated over three consecutive days. The simultaneous assessment (involving large teams) was done to enable direct comparison without spatial sampling being confounded by time. Habitat assessments included measurements of water quality parameters, sediment sampling, and vegetation surveys. Despite their close proximity, creeks differed in both fish community structure and habitat characteristics. Broad Creek had the greatest fish species richness (<em>n </em>= 15), followed by Kemps Creek (<em>n </em>= 14) and Page Creek (<em>n </em>= 10). Mangrove habitats had significantly greater fish species diversity in Broad Creek while sea grass habitats resulted in higher species richness in Page Creek, relative to other habitat types. Mangrove and algal plain habitats had the highest fish species diversity in Kemps Creek. Within creeks, fish abundance was dependent on zonation, with the largest number of fish being found in creek mouths compared to upper sections. Water quality parameters (i.e., temperature, dissolved oxygen, and salinity) differed among the creeks, presumably reflecting creek morphology. Out of the 10 different species of vegetation observed, 60% were found in all tidal creeks. Coarse sand was the predominant particle size for all creeks, with variation in the second most abundant particle size between Page Creek and the others. This study reveals the great heterogeneity of tidal creek fish community and habitat characteristics and illustrates that conservation and management strategies along with monitoring programs must recognize the variation that can occur among and within coastal creeks over relatively small spatial scales.

scholarly journals Expected Shifts in Nekton Community Following Salinity Reduction: Insights into Restoration and Management of Transitional Water Habitats

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1354 ◽  
Author(s):  
Luca Scapin ◽  
Matteo Zucchetta ◽  
Andrea Bonometto ◽  
Alessandra Feola ◽  
Rossella Boscolo Brusà ◽  
...  
Keyword(s):  
Community Structure ◽  
Shallow Water ◽  
Coastal Lagoons ◽  
Venice Lagoon ◽  
Northern Adriatic Sea ◽  
Management Tools ◽  
Important Species ◽  
Northern Adriatic ◽  
Functional Perspective ◽  
Salinity Reduction

A restoration project is planned to take place in the northern Venice lagoon (northern Adriatic Sea, Italy), aiming at introducing freshwater into a confined shallow water lagoon area and recreating transitional water habitats. This work describes the shifts in the nekton (fish and decapods) community structure to be expected following the future salinity decrease in the restoration area. Nekton was sampled at a series of natural shallow water sites located along salinity gradients in the Venice lagoon. A multivariate GLM approach was followed in order to predict species biomass under the salinity and environmental conditions expected after restoration. Biomass of commercially important species, as well as species of conservation interest, is predicted to increase following salinity reduction and habitat changes. From a functional perspective, an increase in biomass of hyperbenthivores-zooplanctivores, hyperbenthivores-piscivores and detritivores is also expected. This study emphasises the efficacy of a predictive approach for both ecological restoration and ecosystem management in transitional waters. By providing scenarios of community structure, the outcomes of this work could be employed in future evaluations of restoration success in the Venice lagoon, as well as to develop management tools to forecast the effects of alterations of salinity regimes in coastal lagoons due to climate change.

Benthic trophic status of aquatic transitional environments with distinct morphological and dynamic characteristics on the south-western Atlantic coast

2017 ◽  
Vol 68 (11) ◽  
pp. 2028 ◽  
Author(s):  
Ana Laura Pita ◽  
Luis Giménez ◽  
Noelia Kandratavicius ◽  
Pablo Muniz ◽  
Natalia Venturini
Keyword(s):  
Organic Matter ◽  
Biochemical Composition ◽  
Trophic Status ◽  
Coastal Lagoons ◽  
Spatial Scales ◽  
Atlantic Coast ◽  
Sedimentary Organic Matter ◽  
Sediment Grain Size ◽  
Western Atlantic ◽  
Food Value

The benthic trophic status of Uruguayan coastal estuarine habitats (permanently open estuaries and open or closed coastal lagoons) was evaluated, twice in 1 year and at different spatial scales, using the amount and biochemical composition of the sedimentary organic matter. Nested hierarchical ANOVAs were applied to evaluate differences at the habitat level, among sites for each type of estuarine habitat (three estuaries and three lagoons) and between sectors located at different distances from the sea (inner v. outer sectors). Morphological and hydrodynamic differences between the two types of habitats explained site-to-site variations in eutrophic conditions in the open or closed coastal lagoons and meso-oligotrophic conditions in permanently open estuaries. These differences followed the patterns found for sediment grain size, with inner sectors (lower-energy areas) favouring the accumulation of finer sediments and higher amounts of degraded–detrital organic matter. In autumn, biochemical parameters indicated the dominance of aged and more degraded organic matter, with both types of habitats having a low nutritional value no matter which sector was considered. By contrast, in spring, biochemical composition showed the prevalence of fresh and more labile sedimentary organic matter with a high food value, especially in the outer sectors.

Pollution and Eutrophication in the Venice Lagoon

1987 ◽  
Vol 19 (5-6) ◽  
pp. 813-822 ◽  
Author(s):  
R. Cossu ◽  
E. de Fraja Frangipane ◽  
D. Degobbis ◽  
A. A. Orio ◽  
G. Andreottola
Keyword(s):  
Water Quality ◽  
Adriatic Sea ◽  
High Water ◽  
Venice Lagoon ◽  
Ammoniacal Nitrogen ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Algae Blooms ◽  
Open Sea ◽  
The City

To reduce the effect of the “high water”, which involves mainly the City of Venice, a project is underway to install barriers in the three port channels which connect the Venice lagoon to the Northern Adriatic Sea. To have a basis on which to gauge any observed effects in the water quality as a consequence of the reduction of the exchange of water between the lagoon and the open sea, a survey on the most polluted area of the lagoon was carried out over the period of a year. The following parameters were determined: pH, temperature, salinity, transparency, dissolved oxygen, ammoniacal nitrogen, orthophosphate, zinc and total coliforms. The results, compared to those obtained from previous studies, show that situation improved for ammoniacal nitrogen, zinc and coliforms and remained fairly constant for the other parameters. The inner zones of the lagoon are much more exposed to eutrophication as a consequence of a lower circulation of water and higher accumulation of nutrients. Release from sediments appears to play an important role in controlling the water quality in the shallow areas. Frequent algae blooms have been observed during spring and summer seasons. There is no evidence of an attenuation of eutrophic phenomena in recent years.

POLÍTICAS DE ESCALA E A CONFORMAÇÃO DE ESTRATÉGIAS-REDE DAS AÇÕES COLETIVAS NO ESPAÇO SISALEIRO DA BAHIA

GEOgraphia ◽  
2018 ◽  
Vol 19 (41) ◽  
pp. 39
Author(s):  
Agripino Souza Coelho Neto
Keyword(s):  
Political Action ◽  
Spatial Scales ◽  
Spatial Behavior ◽  
Collective Actions ◽  
Collective Behaviors ◽  
Rural Workers ◽  
Scale Levels ◽  
Scale Network ◽  
Comme Point

Resumo: O presente texto pretende analisar o papel das ações coletivas (associações, cooperativas e sindicatos de agricultores) no acionamento e na ativação das escalas geográficas para o desenvolvimento de suas atividades. O estudo foi realizado no Espaço Sisaleiro da Bahia (Brasil), onde um conjunto significativo de associações e cooperativas de agricultores e sindicatos de trabalhadores rurais tem se organizado em torno das escalas espaciais para viabilizar sua ação político-institucional e econômico-produtiva. A ação desses coletivos organizados em rede tem permitido a conformação e o fortalecimento de novas escalas de ação política, como no caso da criação do conselho territorial para viabilização da implantação de políticas de governo. Cooperativas, associações e sindicatos se apoiam nas escalas para compor organizações em diferentes níveis escalares (escala local, escala regional, escala do estado federado e escala nacional), buscando fortalecer seus propósitos e ampliar seu poder de barganha e influência. Analisando o comportamento espacial dessas variadas modalidades de ações coletivas, é possível considerar que elas desenvolvem políticas de escala, ou seja, a escala passa a significar muito mais que uma categoria de análise, mas se torna uma categoria da prática social e política. Nesse sentido, parte-se do pressuposto de que os grupos humanos produzem e tornam efetivas suas próprias escalas visando a alcançar suas metas e organizar seus comportamentos coletivos. Palavras-chave: Escala. Rede. Cooperativismo. Associativismo. Sindicalismo. Espaço Sisaleiro da Bahia. SCALE POLICIES AND THE DEVELOPMENT OF NETWORK STRATEGIES OF COLLECTIVE ACTIONS IN THE SISAL REGION OF BAHIA (BRAZIL)Abstract: This paper aims to analyze the role of collective initiatives of associations, cooperatives and farmers’ unions in the mobilization and activation of geographical scales for the development of their activities. The study was conducted in the Sisal Region of Bahia (Brazil), where a significant number of farmers associations and cooperatives and rural workers’ unions have been organizing their actions around spatial scales to enable their political-institutional and economic-productive influence. The gathering and action of these organized groups in a network have allowed the establishment and strengthening of new scales of political action, as seem in the case of the creation of a territorial council to facilitate the implementation of government policies. Cooperatives, associations, and unions rely on scales to form organizations at different scale levels (local, regional, federal and national scales), seeking to strengthen their performance and increase their bargaining power and influence. After analyzing the spatial behavior of these various forms of collective actions, it’s reasonable to say that they develop scale policies, which means the scale becomes more than a category of analysis, but also a category of social and political practice. In this sense, it’s assumed that human groups produce and utilize the scales in order to reach their goals and organize their own collective behaviors. Keywords: Scale. Network. Cooperativism. Associativism. Syndicalism. Sisal Region of Bahia. POLITIQUES D’ÉCHELLE ET FORMATION DES STRATÉGIES-RÉSEAU DES ACTIONS COLLECTIVES DANS LA RÉGION DU SISAL DE L’ÉTAT DE BAHIA Resumé: Cet article analyse le rôle des actions collectives (associations, coopératives et syndicats d’agriculteurs) dans la prise en compte et l’utilisation des échelles géographiques pour le développement de leurs activités. L’étude a été menée dans la région du sisal à Bahia (Brésil), où un ensemble important d’associations et de coopératives d’agriculteurs et de syndicats de travailleurs ruraux se sont organisés autour d’échelles spatiales pour que puisse être mise en place leur action politique et institutionnelle, économique et productive. L’action de ces groupements organisés en réseaux a permis la conformation et le renforcement de nouvelles échelles d’action politique, comme lors de la création du conseil territorial, pour permettre la mise en œuvre des politiques gouvernementales. Les coopératives, les associations et les syndicats prennent les échelles comme point de départ pour former des organisations à différents niveaux scalaires (échelle locale, échelle régionale, échelle fédérée et échelle nationale), dans le but de renforcer leurs objectifs et d’accroître leur pouvoir de négociation et d’influence. Si nous analysons le comportement spatial de ces diverses formes d’action collective il est possible de considérer qu’ils développent des politiques d’échelle, à savoir l’échelle vient signifier bien plus qu’une catégorie d’analyse, puisqu’elle devient une catégorie de la pratique sociale et politique. En ce sens, on suppose que les groupes humains produisent et rendent efficaces leurs propres échelles pour atteindre leurs objectifs et organiser leurs comportements collectifs. Mots-clés: Échelle. Réseau. Coopérativisme. Associations. Syndicalisme. Région du sisal de l’État de Bahia.

scholarly journals The effects of armed conflict on forest cover changes across temporal and spatial scales in the Colombian Amazon

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Oscar V. Bautista-Cespedes ◽  
Louise Willemen ◽  
Augusto Castro-Nunez ◽  
Thomas A. Groen
Keyword(s):  
Armed Conflict ◽  
Forest Cover ◽  
Spatial Scales ◽  
Armed Forces ◽  
Peace Negotiations ◽  
Post Conflict ◽  
Forest Cover Changes ◽  
The Government ◽  
Colombian Amazon

AbstractThe Amazon rainforest covers roughly 40% of Colombia’s territory and has important global ecological functions. For more than 50 years, an internal war in the country has shaped this region. Peace negotiations between the government and the Revolutionary Armed Forces of Colombia (FARC) initiated in 2012 resulted in a progressive de-escalation of violence and a complete ceasefire in 2016. This study explores the role of different deforestation drivers including armed conflict variables, in explaining deforestation for three periods between 2001 and 2015. Iterative regression analyses were carried out for two spatial extents: the entire Colombian Amazon and a subset area which was most affected by deforestation. The results show that conflict variables have positive relationships with deforestation; yet, they are not among the main variables explaining deforestation. Accessibility and biophysical variables explain more variation. Nevertheless, conflict variables show divergent influence on deforestation depending on the period and scale of analysis. Based on these results, we develop deforestation risk maps to inform the design of forest conservation efforts in the post-conflict period.

Patchwork of oil and gas facilities in Saudi waters of the Arabian Gulf has the potential to enhance local fisheries production

2015 ◽  
Vol 72 (8) ◽  
pp. 2398-2408 ◽  
Author(s):  
Lotfi Rabaoui ◽  
Yu-Jia Lin ◽  
Mohammad A. Qurban ◽  
Rommel H. Maneja ◽  
Javier Franco ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Arabian Gulf ◽  
Habitat Characteristics ◽  
Small Fish ◽  
Faunal Assemblages ◽  
Fishery Resources ◽  
Management Measures ◽  
Coastal Embayments ◽  
Oceanographic Variables

Abstract Because of the increasing oil industry development in the Arabian Gulf, hundreds of oil and gas facilities have been installed in both offshore and inshore areas during the last few decades. However, no studies have been conducted till now on the influence of these platforms on the structure and composition of marine faunal assemblages. The present work addresses this issue to propose environmental management measures connected to the utilization of fishery resources. Offshore and inshore surveys were carried out along the Saudi Gulf waters using trawl and beach-seine nets, respectively. Data relative to only fish (offshore) and fish and invertebrates (inshore) were collected concurrently with several factors: density of oil and gas facilities (offshore), distance to the nearest coastal platform (inshore), oceanographic variables, and habitat characteristics. Results of offshore surveys indicated higher fish density—both total and of fishery resources—in locations with a higher number of oil and gas facilities within a 5 km radius, whereas biomass density was not significantly different. Hence, oil and gas facilities seem to serve as nursery areas for small fish. For inshore communities, more species and diversity were found in stations closer to coastal oil and gas facilities. In addition, among the five coastal embayments sampled, those with more oil and gas facilities had more species. The findings of the present work support the hypothesis of a positive net ecological role of oil and gas platforms of the Saudi Arabian Gulf, with the implication that this effect could be extended to improve the sustainability of important fishery resources.

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