In Vitro Evaluation of Antioxidant Potential of the Invasive Seagrass Halophila stipulacea

Marine organisms with fast growth rates and great biological adaptive capacity might have biotechnological interests, since ecological competitiveness might rely on enhanced physiological or biochemical processes’ capability promoting protection, defense, or repair intracellular damages. The invasive seagrass Halophila stipulacea, a non-indigenous species widespread in the Mediterranean Sea, belongs to this category. This is the premise to investigate the biotechnological interest of this species. In this study, we investigated the antioxidant activity in vitro, both in scavenging reactive oxygen species and in repairing damages from oxidative stress on the fibroblast human cell line WI-38. Together with the biochemical analysis, the antioxidant activity was characterized by the study of the expression of oxidative stress gene in WI-38 cells in presence or absence of the H. stipulacea extract. Concomitantly, the pigment pool of the extracts, as well as their macromolecular composition was characterized. This study was done separately on mature and young leaves. Results indicated that mature leaves exerted a great activity in scavenging reactive oxygen species and repairing damages from oxidative stress in the WI-38 cell line. This activity was paralleled to an enhanced carotenoids content in the mature leaf extracts and a higher carbohydrate contribution to organic matter. Our results suggest a potential of the old leaves of H. stipulacea as oxidative stress damage protecting or repair agents in fibroblast cell lines. This study paves the way to transmute the invasive H. stipulacea environmental threat in goods for human health.     

Using object‐based image analysis with multi‐temporal aerial imagery and LiDAR to detect change in temperate intertidal habitats

1. Intertidal habitat maps are needed at both fine and coarse scales to monitor change and inform conservation and management, but current methods of field survey and expert interpretation of aerial imagery can be time‐consuming and subjective. Object‐based image analysis (OBIA) of remote sensing data is increasingly employed for producing habitat or land cover maps. Users create automated workflows to segment imagery, creating ecologically meaningful objects, which are then classified based on their spectral or geometric properties, relationships to other objects and contextual data.
2. This study evaluates the change‐detection capability of OBIA in the intertidal environment by developing and comparing two OBIA methods for quantifying change in extent and distribution of habitats from freely available multi‐temporal aerial imagery and LiDAR data. Despite considerable variability in the data, pre‐ and post‐classification change detection methods had sufficient accuracy (mean overall accuracy from 70.5 to 82.6%) to monitor deviation from a background level of natural environmental fluctuation.
3. This insight into spatial and temporal patterns of natural cyclical change and their detectability by OBIA could inform use of remote sensing for regular, rapid coastal assessment, providing an alert system to direct survey resources to areas of ecologically relevant change.

     

Rescue and relocation of benthic organisms during an urban‐port development project: Port of Manzanillo,case study

1. The present study originated with the expansion of the boardwalk within the urban and port area of Manzanillo, México. Prior to civil works related to the placement of tetrapods, surveys of potential sites for the relocation of benthic organisms in alternative areas were carried out.
2. Based on indicators of the physical–chemical environment and biotic factors, nine areas with potential for relocation were evaluated. The areas of greatest potential were associated with environments located away from the influence of the port environment.
3. A total of 13,559 benthic organisms belonging to 68 species associated with three main substratum types (rocky, sandy, and mixed) were collected. There were no differences in the ecological indices between the three substrata.
4. The proximity of the collection area to the influence of port traffic and sources of pollution associated with the physical environment could be an important factor that affects ecological indices and the reduction in the abundance of some protected species and species of commercial interest.
5. The success of collection and relocation processes depends on minimizing possible errors, especially during transportation, when overcrowding, handling, and damage resulting from variable physico‐chemical conditions should be avoided.
6. Through a scheme of actions based on ecological principles, management actions, and civil engineering technology, it was possible to carry out mitigation, conservation, and habitat improvement actions in coastal marine environments exposed to anthropogenic impacts.

     

Application of multiplatform,multispectral remote sensors for mapping intertidal macroalgae: A comparative approach

1. Intertidal macroalgal communities are economically and ecologically important and, with a likely increase in anthropogenic pressures, there is need to evaluate and monitor these diverse habitats. Efforts to conserve and sustainably manage these habitats must be underpinned by accurate, cost‐effective, and efficient data collection methods. The high spatial and temporal resolution of unmanned aerial vehicles (UAVs), compared with satellites and aircraft, combined with the development of lightweight sensors, provides researchers with a valuable set of tools to research intertidal macroalgal communities.
2. The ability of multispectral sensors, mounted on a satellite, an aircraft, and a UAV, to identify and accurately map the intertidal brown fucoid Ascophyllum nodosum (Fucales, Ochrophyta) at a site with a low species diversity of macroalgae were compared.
3. Visual analysis confirmed that the spatial resolution of satellite imagery was too coarse to map intertidal macroalgae as it could not capture the fine spatial patterns of the macroalgal community. High‐resolution RGB (colour) imagery, taken during the aircraft and UAV surveys, was used to collect training and reference data through the visual identification and digital delineation of species. Classes were determined based on the level of taxonomic detail that could be observed, with higher levels of taxonomic detail observed in the UAV imagery over the aircraft imagery. Data from both were used to train a maximum‐likelihood classifier (MLC).
4. The UAV imagery was able to more accurately classify a distinct A. nodosum class, along with other macroalgal and substratum classes (overall accuracy, OA, 92%), than the aerial imagery, which could only identify a lower taxonomic resolution of mixed A. nodosum and fucoid class, achieving a lower OA (78.9%). This study has demonstrated that in a coastal site with low macroalgal species diversity, and despite the spectral similarity of macroalgal species, UAV‐mounted multispectral sensors proved the most accurate for focused assessments of individual canopy‐forming species.

     

Gear-based management of a tropical artisanal fishery based on species selectivity and capture size

The population density, species composition and lengths of fish landed by artisanal fishermen using six types of gear: large and small traps, gill nets, hand lines, spears and beach seines were studied in the multi‐species fishery of southern Kenya. Selectivity and catch composition among gears were determined by studying the species richness, diversity, size and mean trophic level of the catches for each gear type, to develop gear‐based management recommendations for this artisanal reef lagoon fishery. One hundred and sixty‐three reef and reef‐associated species from 37 families were recorded in the catch. Beach seines and small traps accounted for the highest number of fish landed (34–35 individuals per fisherman per day). These gears also caught smaller fish than big traps, spears and gill nets. Beach seines caught the highest number of species (14 ± 7 species per day) while most other gears caught four to five species per day with no differences between gears. Predatory species with a mean trophic level of 3.6 dominated catches from hand lines, while the mean trophic level of the other gears was low and ranged from 2.6 to 2.9 with no differences between the gears. The high diversity and small size of fish caught in beach seines indicates that its selectivity overlapped most with large traps and gill nets. Spears and small traps also showed high similarity in species selectivity and small traps captured the smaller mean size of fish, indicating that they are likely to pre‐empt the resource of spears. Large traps, hand lines and spears catch the largest individuals and the species composition of the catch differed sufficiently such that their selectivity should overlap the least and may, therefore, be the preferred mix of gears. The elimination or reduction of beach seines and small traps should reduce the catch of small fish and overlap in selectivity among the existing gears.     

Intertidal habitat conservation: identifying conservation targets in the absence of detailed biological information

• 1. Growing concern associated with threats to the marine environment has resulted in an increased demand for marine reserves that conserve representative and adequate examples of biodiversity. Often, the decisions about where to locate reserves must be made in the absence of detailed information on the patterns of distribution of the biota. Alternative approaches are required that include defining habitats using surrogates for biodiversity. Surrogate measures of biodiversity enable decisions about where to locate marine reserves to be made more reliably in the absence of detailed data on the distribution of species.
• 2. Intertidal habitat types derived using physical properties of the shoreline were used as a surrogate for intertidal biodiversity to assist with the identification of sites for inclusion in a candidate system of intertidal marine reserves for 17 463 km of the mainland coast of Queensland, Australia. This represents the first systematic approach, on essentially one‐dimensional data, using fine‐scale (tens to hundreds of metres) intertidal habitats to identify a system of marine reserves for such a large length of coast. A range of solutions would provide for the protection of a representative example of intertidal habitats in Queensland.
• 3. The design and planning of marine and terrestrial protected areas systems should not be undertaken independently of each other because it is likely to lead to inadequate representation of intertidal habitats in either system. The development of reserve systems specially designed to protect intertidal habitats should be integrated into the design of terrestrial and marine protected area systems.

Copyright © 2005 John Wiley & Sons, Ltd.     

Comparison of invertebrate abundance in a seagrass bed and adjacent coral and sand areas at Amitori Bay,Iriomote Island,Japan

ABSTRACT:   To examine whether or not reef-associated seagrass beds harbor abundant food resources for resident and visiting fishes, the invertebrate density and biomass in a seagrass bed were compared with those in adjacent coral and sand areas at Amitori Bay, Iriomote Island, Japan, in June 2002. The vegetation within the bed was dominated by Enhalus acoroides , the coral area comprising primarily Acropora spp. Epifaunal density was greater on the seagrass than on the corals, whereas biomass was greater on the latter. Tanaids, chironomid larvae, errant polychaetes, and gammaridean amphipods were dominant taxa on the seagrass; larger crustaceans, such as crabs and shrimps, being abundant on the corals. The density of infauna was greatest in the seagrass bed, followed by the coral and sand areas, whereas biomass was greatest in the coral area, followed by the seagrass bed and sand area. Each of the three habitats was dominated by harpacticoid copepods and errant polychaetes, although the density of each taxonomic group differed among the habitats. Important food items of seagrass bed fishes, such as harpacticoid copepods, gammaridean amphipods, errant polychaetes, and tanaids, were abundant in the seagrass bed, the density of each being greater than in the other two habitats.     

Growth and habitat of spotted halibut Verasper variegatus in the shallow coastal nursery area, Shimabara Peninsula in Ariake Bay, Japan

ABSTRACT:   To determine the growth performances and habitat characteristics of spotted halibut Verasper variegatus , successive samplings were conducted in the south-eastern coastal area of Shimabara Peninsula in Ariake Bay. The push-net samplings were performed at Kamaga beach from May 2003 to April 2004 to determine the horizontal distribution of larvae and juveniles, while the gill net samplings were done in the coastal waters of Tatsuishi beach from July 2003 to July 2004 to collect the larger juveniles and adults. A total of 478 individuals from metamorphosing larvae to 2-year-old fish (15.2–447.0 mm total length [TL]) were sampled. In particular, the 2003-year class fish were successively collected from May 2003 to June 2004 (15.2–350.0 mm TL; n  = 418) and the mean total length in March, June, September, December 2003 and May 2004 was 22.4, 82.5, 172.5, 203.9 and 296.4 mm, respectively. The present study found that metamorphosing larvae migrated into the estuarine tidal flats during March 2003; newly settled juveniles inhabited the shallow intertidal areas; and juveniles had a remarkably high growth in shallow coastal areas. It is suggested that young fish around 300 mm TL migrated from the nursery grounds in Ariake Bay to deeper waters around Tachibana Bay during May–June 2004.     

海草及海草场生态系统研究进展

海草是分布于全球各地浅海中的重要沉水被子植物,具有极高的应用价值;海草与周围环境形成一个独特的生态系统——海草场生态系统,是生物圈中最具生产力的水生生态系统之一,且强大的吸收和固碳能力使其成为全球最大的碳库之一;海草场具有多种重要的生态服务功能;被广泛视为是理想的“生态哨兵”来衡量近海岸生态系统健康状况。如今由于自然因素和人为破坏活动的双重干扰,全球海草种的数量和海草场的覆盖面积正在急剧减少,海草生存状况面临严峻的考验,约14%的海草种处于灭绝的边缘,1/3的海草场彻底消失。目前,海草监测工程和以生境恢复与人工移植为主的海草保护恢复工程已经开始实施,并取得初步成效,对今后全球范围内海草保护恢复工作具有重要指导作用,但该工程还仅仅处于起步阶段,取得更多技术理论上的突破和政策上的支持才能实现挽救濒危海草种及缓解海草场生态系统破坏现状的目标。本文通过对全球海草及海草场生态系统研究成果的总结,阐述了海草和海草场对全球生物圈的重要性以及面临的严峻生存压力,以期提高公众对海草的认识,并唤起人们保护海草的意识。     

Earthquake‐induced habitat migration in a riparian spawning fish has implications for conservation management

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