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1.
Andrew Bakun Elizabeth A. Babcock Salvador E. Lluch-Cota Christine Santora Christian J. Salvadeo 《Reviews in Fish Biology and Fisheries》2010,20(1):9-29
The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management
(EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small
pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps
subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale
and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient
aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced
trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition
to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management
system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing
surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable
in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes
and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing
the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization. 相似文献
2.
W. F. Frud'homme van Reine 《Helgoland Marine Research》1988,42(2):165-185
189 species of seaweeds have been recorded for the Atlantic archipelago of the Azores (114 Rhodophyceae, 41 Phaeophyceae and
34 Chlorophyceae). Ten of these have been described as endemic algae. The taxonomic status of these “endemics” is far from
clear, however. Studies on the relatedness of this seaweed flora to seaweed floras of surrounding areas using clustering methods
indicate its intermediary position between the seaweed floras of the subtropical Macaronesian Islands (Canaries Madeira and
Salvages) on the one side and those of the warm temperate Eurafrican coasts on the other side. The geographic position of
the Azores is NW of the other Macaronesian Archipelagos and thus nearer to the American coast. The Gulf stream may easily
transport seaweeds from the Carribean to the Azores. Nevertheless, the number of species of these islands in common with the
American Atlantic coast is much lower than with, for example, the W. Mediterranean. Of one group of seaweeds, viz. algae with
a strictly warm temperature distribution, not a single species occurs likewise on American coasts. This absence is probably
explicable because of the narrow temperature range for survival of these seaweeds. Temperatures of surface waters around the
Azores during pleistocene glaciations were not much lower than they are at present. Nevertheless, it can be supposed that
a number of seaweeds now occurring in the Azores have become extinct during the last glaciation.
Paper presented at the XIV International Botanical Congress (Berlin, 24 July–1 August, 1987), Symposium 6-15, “Biogeography
of marine benthic algae”.
CANCAP-project. Contributions to the zoology, botany and paleontology of the Canarian-Cape Verdean region of the North Atlantic
Ocean. No. 67. 相似文献
3.
Alejandro H. Buschmann Carolina Camus Javier Infante Amir Neori Álvaro Israel María C. Hernández-González 《欧洲藻类学杂志》2017,52(4):391-406
ABSTRACTThe use of seaweeds has a long history, as does the cultivation of a select and relatively small group of species. This review presents several aspects of seaweed production, such as an update on the volumes of seaweeds produced globally by both extraction from natural beds and cultivation. We discuss uses, production trends and economic analysis. We also focus on what is viewed as the huge potential for growing industrial-scale volumes of seaweeds to provide sufficient, sustainable biomass to be processed into a multitude of products to benefit humankind. The biorefinery approach is proposed as a sustainable strategy to achieve this goal. There are many different technologies available to produce seaweed, but optimization and more efficient developments are still required. We conclude that there are some fundamental and very significant hurdles yet to overcome in order to achieve the potential contributions that seaweed cultivation may provide the world. There are critical aspects, such as improving the value of seaweed biomass, along with a proper consideration of the ecosystem services that seaweed farming can provide, e.g. a reduction in coastal nutrient loads. Additional considerations are environmental risks associated with climate change, pathogens, epibionts and grazers, as well as the preservation of the genetic diversity of cultivated seaweeds. Importantly, we provide an outline for future needs in the anticipation that phycologists around the world will rise to the challenge, such that the potential to be derived from seaweed biomass becomes a reality. 相似文献
4.
Synopsis In Nova Scotia the annual harvest of the intertidal seaweed Ascophyllum nodosum exceeds 20 000 tons. This study investigated the possible impact of removal of the seaweed on intertidal abundance of fishes and their gut contents. At sites near Lower Argyle, Nova Scotia, absolute abundance of fish in small areas with Ascophyllum removed and intact was determined with pop-up seines. Gut contents were investigated from fish collected with the seines and with trammel nets. Number and weight of fish were not significantly different between cleared and intact areas and averaged 4.6 individuals and 160 g per 400 m2 during June to October. Cunner and sculpins had more food in their guts when leaving than when entering the intertidal, but only cunner had more food in their stomachs when leaving intact areas than when leaving cleared areas. Most fish captured in the intertidal were small (< 15 cm) and of no commercial value, and the numbers of commercial species were too low to be of much value. Numbers of fish in the intertidal was significantly lower than in the shallow subtidal. This study provided no evidence for adverse effects of the removal of patches of Ascophyllum on fishes. 相似文献
5.
The kelp Undaria pinnatifida(Phaeophyceae) is a seaweed native to northeast Asia, but during the last two decades, it has been accidentally or intentionally introduced in several temperate coasts worldwide. In central Patagonia (Argentina), this species was first detected in late 1992, and it is progressively spreading from the point of introduction. Through a manipulative experiment involving Undaria removal in 2001, we found that its presence is associated with a dramatic decrease in species richness and diversity of native seaweeds in Nuevo Gulf. Future prospects are worrisome, as, in addition to the negative impact from a biodiversity viewpoint, native commercial macroalgae and invertebrates might also be affected. 相似文献
6.
Rábago-Quiroz CH López-Martínez J Valdez-Holguín JE Nevárez Martínez MO 《Revista de biología tropical》2011,59(1):255-267
The Gulf of California is one of the most mega-diverse regions in the world, for which few fishery information is available. We present here latitudinal and bathymetric distribution of the most abundant and frequent bycatch species from the Gulf of California. The samples were obtained from a total of 111 hauls taken during seven research cruises of the closed shrimp season (2002-2005-2007), and also, from research cruises made at depths up to 90 m. Due to the high variety species in this experimental shrimp bycatch, only those with highest biological value index (BVI) were selected. A total of fifteen species had the highest BVI and represented about 60% of the total abundance. A total of 16 508 organisms were analyzed, representing 243 fish, crustacean, mollusk and echinoderm species. Fish were the most abundant, being the most frequent species: Urobatis halleri, Synodus scituliceps, Diplectrum pacificum, Haemulopsis nitidus and Eucinostomus argenteus. A wide latitudinal distribution of these species along the study area, as well as a bathymetric distribution from 9 to 67 m depth, was observed. Two of these species were found at 325 m depth. Due to the wide bathymetric distribution obtained, total abundances and sizes for each species by depth strata should be determined, and one can assume that deeper than 25 m, the capture of these species decreases, and these areas can be used as natural repopulation areas, for depths where they are mainly captured by the commercial shrimp fishery. 相似文献
7.
C. R. K. Reddy Bhavanath Jha Yuji Fujita Masao Ohno 《Journal of applied phycology》2008,20(5):609-617
The seaweed industry worldwide uses 7.5–8.0 million tonnes of wet seaweeds annually with a majority of it derived from cultivated
farms, as the demand for seaweed based-products exceeds the supply of seaweed raw material from natural stocks. The main advantage
of cultivation is that it not only obviates overexploitation of natural populations but also facilitates the selection of
germplasm with desired traits. To enhance the economic prospects of seaweed cultivation, varied practices, such as simple
and cost effective cultivation methods, use of select germplasm as seed stock coupled with good farm management practices,
etc., are adopted. Nevertheless, in vitro cell culture techniques have also been employed as they facilitate development and
propagation of genotypes of commercial importance. There are more than 85 species of seaweeds for which tissue culture aspects
have been reported. Although the initial aim of these techniques focuses mostly on genetic improvement and clonal propagation
of seaweeds for mariculture, recently the scope of these techniques has been extended for use in bioprocess technology for
production of high value chemicals of immense importance in the pharmaceutical and nutraceutical sectors. Recently, there
has been a phenomenal interest in intensifying seaweed tissue and cell culture research to maximize the add-on value of seaweed
resources. This paper deals with the status of seaweed micropropagation techniques and their applications in the context of
the marine biotech industry. Further, it also provides an analysis of the problems to be resolved for removing the barriers
that are impeding the true realization of potentials offered by these techniques for sustainable development and utilization
of seaweed resources. 相似文献
8.
Macroalgae provide a substantial and renewable resource that can be sustainably utilized for economic and social benefit. A US$7 billion global industry already exists for macroalgae, but the huge majority of this is based on the production of species belonging to approximately six genera, within eight countries, for the manufacture of foods, industrial biomaterials and agricultural products. However, seaweed-derived functional products spanning numerous chemical classes have been identified with valuable therapeutic and industrial applications. This review focuses on the breadth of valuable bioproducts that could be produced from the seaweeds of Southern Australia—a hotspot for seaweed diversity, and the pathways available for their sustainable commercial production. This region contains among the highest level of recorded macroalgal diversity and endemism in the world, with approximately 1,200 described species, of which 62 % are considered endemic. Whilst a number of these species have been shown to be rich sources of higher-value functional products, and most of them still await exploration in this field, the seaweed industry of Southern Australia is largely limited to the harvest of beach-cast biomass for the manufacture of lower-value commodities such as fertilizer and animal feed. There is potential for the development of a substantial industry based on human functional products from seaweeds in Southern Australia. However, a number of challenges and knowledge gaps—including environmental, technological, agronomic, political, and cultural factors—are identified in this review, which must be addressed before sustainable expansion can be achieved. Furthermore, numerous strategic approaches and areas of suggested foci are underscored for research bodies and industry alike. Particular emphasis is given to the need for comprehensive surveying and bioprospecting of the resource; a focus on advanced downstream processing capabilities for improving production efficiency and enhancing product value; the use of biorefinery approaches to improve utilisation efficiency; and pursuing means of improving the sustainability of supply chains. 相似文献
9.
Dennis J. McHugh 《Hydrobiologia》1991,221(1):19-29
The commercial exploitation of seaweeds for use as food and for the production of agar, alginate and carrageenan is outlined. The quantities of seaweed harvested for each purpose are tabulated and discussed. Seaweeds for food are derived chiefly from China, Japan and Korea, with almost 94% obtained by cultivation. Alginophytes are collected in 15 countries but six of these account for more than 80% of the total harvest; all are from natural stocks except for a large quantity of Laminaria cultivated in China. Natural carrageenophytes, from 12 countries, now account for only 20% of the total harvest; the remainder is cultivated Eucheuma species, 99% of which is produced in only two countries, the Philippines and Indonesia. Of the four categories of commercial resources of seaweeds considered, agarophytes are spread more evenly over a greater number of countries; they come from 20 countries and only five of these are minor contributors to the total. Gelidium species are particularly important because of the high quality agar they yield; their distribution and location are discussed. 相似文献
10.
In the coastal areas of Japan, three species of greenling (Hexagrammos spp.) can hybridize. In a natural reef setting we showed that Hexagrammos agrammus and H. octogrammus established their breeding territories in a shallow area where seaweed was abundant, whereas H. otakii established breeding territories in a deep area that was sparsely covered with seaweed. This difference in habitat use resulted in H. otakii being distributed separately from the other two species, thereby reducing the potential for hybridization. However, all the three species co-occurred in an artificial area near a breakwater. This area is characterized by steep slopes and complex stacked concrete structures, which create a mosaic-habitat consisting of a shallow environment with seaweed and a deep environment with sparse seaweed, allowing the three species to breed within a single area. Our results suggest that man-made structures can create an artificial mosaic-habitat that can disrupt habitat isolation and promote hybridization between species. 相似文献
11.
Non-indigenous species (NIS) are important components of global change, and in order to manage such species it is important
to understand which factors affect their success. Interactions with enemies in the new range have been shown to be important
for the outcome of introductions, but thus far most studies on NIS–enemy interactions have considered only specialist herbivores
in terrestrial systems. Here we present the results from the first biogeographic study that compares herbivore resistance
between populations in the native and new region of a non-indigenous seaweed. We show that low consumption of the non-indigenous
seaweed by a generalist herbivore is caused by higher chemical defence levels and herbivore resistance in the new range—and
not by the failure of the herbivore to recognise the non-indigenous seaweed as a suitable host. Since most seaweed–herbivore
interactions are dominated by generalist herbivores, this pattern could be common in marine communities. Our results also
reveal that traits used to predict the invasive potential of species, such as their resistance to enemies, can change during
the invasion process, but not always in the way predicted by dominant theories. 相似文献
12.
13.
Genetic evidence for extreme polyandry and extraordinary sex-role reversal in a pipefish. 总被引:3,自引:0,他引:3
A G Jones D Walker J C Avise 《Proceedings. Biological sciences / The Royal Society》2001,268(1485):2531-2535
Due to the phenomenon of male pregnancy, the fish family Syngnathidae (seahorses and pipefishes) has historically been considered an archetypal example of a group in which sexual selection should act more strongly on females than on males. However, more recent work has called into question the idea that all species with male pregnancy are sex-role reversed with respect to the intensity of sexual selection. Furthermore, no studies have formally quantified the opportunity for sexual selection in any natural breeding assemblage of pipefishes or seahorses in order to demonstrate conclusively that sexual selection acts most strongly on females. Here, we use a DNA-based study of parentage in the Gulf pipefish Syngnathus scovelli in order to show that sexual selection indeed acts more strongly on females than on males in this species. Moreover, the Gulf pipefish exhibits classical polyandry with the greatest asymmetry in reproductive roles (as quantified by variances in mating success) between males and females yet documented in any system. Thus, the intensity of sexual selection on females in pipefish rivals that of any other taxon yet studied. 相似文献
14.
The Gulf of Paria is a semi-enclosed shallow basin with increasing coastal development activities along Trinidad's west coast. Sediments present a host for trace metal pollutants from overlying waters, therefore determination of their content is critical in evaluating and detecting sources of marine pollution. This paper presents a Geographic Information System (GIS) analysis of geochemical assessment for trace metals in coastal sediments of the Gulf of Paria. This GIS approach facilitates interpretation of the spatial relationships among key environmental processes. The GIS development involves the integration of spatial and attribute data pertaining to bathymetry, current systems, topography, rivers, land use/land cover and coastal sediments. It employs spatial interpolation and retrieval operations to analyze the total trace metal concentrations of aluminum, copper and lead in the sediments and the clay-enriched sediments, to determine whether they are related to sediment type or are affected by the discharge from anthropogenic sources. Spatial distribution modeling of element concentrations are produced to indicate contamination plumes from possible anthropogenic sources such as rivers entering the Gulf of Paria, and to reveal potential hot spots and dispersion patterns. A direct spatial correlation between clay-enriched sediments and high concentrations of aluminum and lead is detected, however regions of high concentrations of copper and lead indicate a relationship to anthropogenic sources. The effectiveness of GIS for visualization, spatial query and overlay of geochemical analysis is demonstrated. 相似文献
15.
This paper compares the biofilter capacity and cost-effectiveness of blue mussels (Mytilus edulis) and seaweed for use in integrated multi-trophic aquaculture (IMTA) based on experiences in Ireland and Denmark. This comparison shows that weight for weight, mussels are a better biofilter than seaweed with regard to the amount of nitrogen assimilated. Furthermore, in optimized systems, areal requirement for mussels is similar to the cultivation of the same tonnage (1,000 t) of seaweed (approximately 8 ha). The cost-effectiveness of a mussel biofilter is €11–30 kg?1 nitrogen (N) removed based on various examples compared to production costs of €209–672 removed and €1,013 kg?1 N removed, respectively, for Laminaria digitata and Alaria esculenta from extrapolated laboratory and field trials. However, commercial seaweed (Saccharina latissima) producers claim that production costs are less than €10–38 kg?1 N removed. These up-scaled and commercial figures make the seaweed cost competitive to mussels for removal of nitrogen. Disadvantages such as predators (e.g. eider ducks) and biofouling should also be taken into account before choice of biofilter is made. These drawbacks can reduce overall biofilter capacity and biomass value as a consequence of biomass spoilage or loss. However, disadvantages may be mitigated by seasonal choice of cultivation and harvest times. Cultivation technologies and harvesting methods may be improved together with breeding to improve the cost-efficiency of the biofilter, especially in the newer European seaweed cultivation. Furthermore, upscaling of IMTA to commercial proportions, other than the Danish example, would allow more real data on production costs and revenues. 相似文献
16.
The intensification of agriculture has significant environmental consequences. This intensification entails the simplification and homogenisation of the landscape, which leads to strong negative impacts at ecosystem level, including declines in animal biodiversity. The purpose of this study was to assess the effect of different land uses on reptilian and amphibian biodiversity patterns at a regional scale by analysing a large database on the presence of amphibians and reptiles in Andalusia (southern Spain). GIS techniques and the Ecological-Niche Factor Analysis (ENFA) were applied in order to assess whether the habitat was suitable for each reptilian and amphibian species, when the land use variables were excluded. The incongruence between the potential and the observed species richness was then correlated with the main types of land use in Andalusia. Our results showed that irrigated and unirrigated olive groves were associated with a biodiversity deficit of amphibians and reptiles respectively, whereas natural forests and pastures, along with more heterogeneous crops areas, were more suitable. A clustering analysis showed that generalist species were related to olive groves whereas rare and specialist species were related to land uses related to natural vegetation. In summary, our results indicate that large areas covered by olives groves harbour less amphibian and reptilian diversity, thus suggesting that agro-environmental schemes should be carried to promote the species richness in these crops. 相似文献
17.
This study assessed the possibility of using drift and subtidal seaweeds from St Lawrence Island, Alaska (lat. 63°N) for sale
by the native population after simple processing. Over 125 km of coastline were surveyed for distribution of both drift and
subtidal seaweeds. Drift seaweed wet weight densities ranged from 0.2 to over 9 kg m−2, with an average of over 4 t km−1 in the areas sampled. Attached, benthic seaweed densities ranged from 0.15 to 0.32 kg m−2. Thirty and 35% of the biomass was composed of Agarum cribrosum and species of Laminaria, respectively, both as drift and as benthic seaweed. Data from tagged Laminaria indicated that growth rates were relatively slow for most of the year. The drift seaweed resource on the coasts south and
west of the city of Gambell appeared to have good potential for a small-scale commercial harvest.
(*author for correspondence) 相似文献
18.
There is growing interest in systematic establishment of marine protected area (MPA) networks and representative conservation sites. This movement toward networks of no-take zones requires that reserves are deliberately and adequately spaced for connectivity. Here, we test the network functionality of an ecoregional assessment configuration of marine conservation areas by evaluating the habitat protection and connectivity offered to wide-ranging fauna in the Gulf of California (GOC, Mexico). We first use expert opinion to identify representative species of wide-ranging fauna of the GOC. These include leopard grouper, hammerhead sharks, California brown pelicans and green sea turtles. Analyzing habitat models with both structural and functional connectivity indexes, our results indicate that the configuration includes large proportions of biologically important habitat for the four species considered (25-40%), particularly, the best quality habitats (46-57%). Our results also show that connectivity levels offered by the conservation area design for these four species may be similar to connectivity levels offered by the entire Gulf of California, thus indicating that connectivity offered by the areas may resemble natural connectivity. The selected focal species comprise different life histories among marine or marine-related vertebrates and are associated with those habitats holding the most biodiversity values (i.e. coastal habitats); our results thus suggest that the proposed configuration may function as a network for connectivity and may adequately represent the marine megafauna in the GOC, including the potential connectivity among habitat patches. This work highlights the range of approaches that can be used to quantify habitat protection and connectivity for wide-ranging marine species in marine reserve networks. 相似文献
19.
The African White-backed Vulture Gyps africanus is widely distributed across sub-Saharan Africa but populations are in decline. Loss of suitable habitat for foraging and breeding are among the most important causes, and future conservation will require identification of suitable remaining habitat and the threats to it and to the vultures in it. Like many large raptors, African White-backed Vultures have a long breeding cycle and thus spend much of each year near their nest site, but ecological correlates of nest sites have not been quantified for any African vulture species. We use nest-site data for African White-backed Vultures collected during aerial and ground surveys and habitat data derived from a GIS to develop statistical models that estimate the probability of nest presence in relation to habitat characteristics, and test these models against an independent dataset. The models predicted that both direct and indirect disturbance by humans limit the potential distribution. Suitable habitat needs to be identified and receive adequate protection from poaching. Poaching of vultures is thought to be mainly for use in traditional medicine and does not target any particular species, so all vulture species can be considered equally at risk. We predict the likelihood of individuals nesting in currently unprotected areas should they become protected. These predictions show that readily available GIS data combined with relatively simple statistical modelling can provide meaningful large-scale predictions of habitat availability. 相似文献
20.
Cleber Valim Alexandre Katharina Eichbaum Esteves Mônica Accaui Marcondes de Moura e Mello 《Hydrobiologia》2010,641(1):97-114
This study investigated the fish fauna of a stream in southeastern Brazil that runs through sugar cane-growing and urban areas
that are subject to sewage discharge. It aimed to determine the importance of spatial and environmental factors on fish distributions
and to assess the use of fish as indicators of the environmental conditions. A longitudinal pattern of chemical water quality
was observed, with more disturbed conditions at the urban sites. Several opportunistic or tolerant and omnivorous species
such as Astyanax altiparanae, Poecilia reticulata, and Astyanax fasciatus were numerically abundant at these urban sites, which resulted in a consistent increase in species density and biomass along
the stream. Redundancy analysis extracted three axes, identifying a nutrient–productivity gradient associated with different
species composition patterns, as also detected by the indicator species analysis. No species could be considered a potential
indicator of the agricultural area in the dry season, whereas four different species were judged potential indicators of three
urban sites. In order to explain species distribution, variation in species abundance was partitioned into spatial and environmental
components. The latter was more important, explaining 25.4% of the variation. We concluded that the fish assemblage of the
Guamium stream is undergoing the initial stages of disturbance, with pronounced effects at the urbanized area, but no detectable
changes at the sugar cane sites. Therefore, fish assemblages might be used as ecological indicators to detect urban impacts
in similar rivers. However, the potential use of fish to diagnose stressors in areas of sugar cane plantations should be complementary
to more comprehensive studies aimed at understanding the influence of this crop on freshwater resources. 相似文献