Nonetheless, C. Caulerpa 's life cycle is therefore poorly understood. Most siphonous green algae are primarily diploid; the gametes are the only haploid cells in the life cycle 3. Due to its siphonous nature, no cross-walls are present, housing multinucleated cells coenocytic packed with chloroplasts. So when sexual reproduction does occur, the individual nuclei undergo meiosis.
This yields 4 gametes for every nucleus, which are separated by cell walls fig. Hence, this process involves "holocarpy", in which the entire protoplasm gives rise to gametes at once; i.
Upon merger of the gametes, the zygote develops into a protonema, which then forms a typical diploid 2n thallus 3. Since C. According to Meinesz, C. But over more than 10 years that he has observed this species in the Med and in the lab, he has never seen evidence of sexual reproduction. In the wild, though, the only reproductive cells released are male fig.
Genetically, this invasive species shows relatively little variation, thus vegetative reproduction by fragmentation is the most common mode of proliferation asexual or clonal propagation. The break-up of thalli mediated via anchor damage, fishing gear or storm activity as small as 1cm 2 gives rise to new colonies that usually appear in 2 to 10m deep water 3. Nutrient dynamics : Little is known about the nutrient dynamics of C.
Studies on other members of Caulerpales suggest the existence of some of these features. Therefore the alga was shown to be tolerant to shading conditions 3. As mentioned above, enrichment of sediment with inorganic components originating from wastewater discharges, are some of the prerequisites for the alga's success in the N-W Mediterranean.
This assumption was confirmed by recent studies indicating that C. Once C. These are usually conditions that kill most autochthonous algal species that have been tested in studies on algal mats in eutrophicated waters 3. Take up of these substances is facilitated via the excretion of metabolites that chelate metals, making them soluble and available to C. On the other hand, Caulerpa is also capable of returning a large percentage of its absorbed substances to the environment - especially during the die-off periods of the cooler season.
Field observations revealed that floating fragments of C. However, invasive populations of C. There is, however, some indirect evidence for sexual reproduction and hybridization in the derivation and breeding of invasive populations Meusnier et al. Invasive populations in southeastern Australia had smaller fronds and stolons than native populations in Mooreton Bay, Queensland, but achieved greater density and biomass, including a higher density of fragmented fronds Wright In the Mediterranean, dispersal of drifting fragments by currents, and human transport of fragments by hull fouling, fishing gear, or other means are the major mechanisms of spread Belsher and Meinesz ; Ceccherelli and Cinelli A temperature of It was thought that the 'aquarium strain' may have been accidentally selected for cold tolerance Meinesz and Hesse ; Komatsu et al.
However, native populations from subtropical Moreton Bay, Queensland, Australia have temperature-survival and growth characteristics similar to introduced populations from the Mediterranean and southeast Australia Chisholm et al.
In southeastern Australia, C. Sudden transfers to a salinity of 10 PSU will kill C. In the Mediterranean, C. Although this alga is rare or absent in intertidal areas, large clumps of C. Mediterranean C. Weak light favors lengthening and branching of the fronds.
The capability for growth at low light explains the occurrence of plants at depths up to 55 to 99 m although it is most abundant at m Meinesz and Hesse ; Belsher and Meinesz Invasive populations of Caulerpa taxifolia grow in harbors, lagoons, and open coasts, on sandy, rocky, muddy bottoms, and seagrass beds Posidonia oceanica and Cymodocea nodosa , in the Mediterranean Sea Meinesz and Hesse Introduced populations in southeastern Australia are confined to semi-enclosed lagoons Millar ; Glasby ; Burfeind et al.
In Australian lagoons, C. Similar negative effects were observed on Eelgrass Zostera marina in Agua Hedionda Lagoon, before the eradication of C. In the Mediterranean, recruitment of C. Caulerpa taxifolia , like other Caulerpa , produces a wide range of compounds notably caulerpenyne and caulerpicine which discourages fish and invertebrate grazers Meinez and Hesse Caulerpa was not an adequate diet for the Mediterranean sea urchin Paracentrotus lividus Boudouresque et al.
In Australia, several herbivorous organisms, including a fish Girella tricuspidata , an amphipod Cymadusa setosa , and a sea hare Aplysia dactylomela strongly preferred other algae as food.
A polychaete, Platynereis dumerilii antipoda , did survive well while feeding on C. One of the few groups of organisms feeding on Caulerpa spp. Two native Mediterranean sea-slugs, Oxynoe olivacea and Lobiger serradifalci , feed on native Caulerpa prolifera , but have low feeding rates and low recruitment on C. Species Groups. Caulerpa taxifolia invasive genotype Algae 'Killer Algae'. Regional Distribution Map. Occurrence Map. Description The thalli of green algae of the genus Caulerpa lack cell walls and consist of tubular filaments.
Fucus taxifolius Vahl, Caulerpa pennata J. Lamouroux, Potentially Misidentified Species. Caulerpa mexicana Native to the western Atlantic - Georgia to Brazil.
Caulerpa taxifolia var. The fronds are slender, up to 40 mm tall and mm wide. Ecology General: Sexual reproduction is uncommon in the genus Caulerpa , but is known in at least one population of C. Field Mediterranean, Gacia et al. No growth below Maximum Height mm Meinesz and Hesse , height of a frond in deep water, below 10 m. This alga's dramatic spread in the Mediterranean, the initially chaotic response from governments and the press, and Caulerpa 's far-reaching impacts on marine communities and food webs helped raise the awareness of scientists and policy-makers on the issue of biological invasions Boudouresque et al.
In particular, the Caulerpa invasion led to increased scrutiny of public aquaria and the private aquarium trade Diaz et al. The invasion also spurred coastal managers to develop strategies for rapid response, with emphasis on eradication Thresher and Kuris ; Locke and Hanson In the Mediterranean Sea, the areal extent of the invasion reached its peak in , and it has since disappeared from some of the colonized areas Meinesz et al.
However, a new population was established in Izmir Bay, Turkey in Turan et al. The cause of the decline of C. Economic impacts Aesthetic- The 'aquarium strain' of C. Consequently, it has been widely sold in the aquarium trade, together with other species of Caulerpa Stam and Olsen ; Zaleski and Murray ; Smith et al. After the California invasion and eradication, C. California banned the sale of C.
These bans appear to have been partially effective, but the sale of algae over the Internet makes the prevention of illegal sales difficult Walters et al. Eradication- The cautionary story of the Caulerpa invasion in the Mediterranean, and some other successful eradications Thresher and Kuris , helped prompt a rapid, organized response to the discovery of C.
The fortuitous discovery of the alga during a survey of Eelgrass Zostera marina was helpful, as was the small size of the colonies, and the estuaries to be treated. Motivations for the eradication program included biotic integrity of native seaweed and seagrass, recreational value diving, boating, fishing , and coastal property values. The affected lagoons do not support commercial fisheries and the probability of extensive spread in the open coast is unlikely. The Mediterranean and California invasions, as well as the Atlantic Lionfish invasions, have led to increased scrutiny and regulation of the aquarium industry, including surveys of Caulerpa spp.
Biological control was studied as a possible means to reduce outbreaks of C. This alga, like others of its genus including native Mediterranean species, concentrates a wide range of compounds notably caulerpenyne and caulerpicine which renders it inedible to most grazers. Two native saccoglossan sea slugs Oxynoe olivacea and Lobiger serradifalci were observed to eat C.
Mass rearing would be required to control the invasive alga Thibaut and Meinesz An exotic saccoglossan, Elysia subornata , from the Caribbean was found to graze C. Fisheries- The dense growths of C. The effects on populations of commercial fishes, due to changes in habitat and food webs, is more difficult to determine, but some fishes appear to have reduced abundance in C.
Eradication of the invasive seaweed Caulerpa taxifolia by chlorine bleach. Withgott J, California tries to rub out the monster of the lagoon. Science Washington , Wright JT, Differences between native and invasive Caulerpa taxifolia: a link between asexual fragmentation and abundance in invasive populations.
Marine Biology, 2 Demographic feedback between clonal growth and fragmentation in an invasive seaweed. Ecology, 87 7 A decline in the abundance and condition of a native bivalve associated with Caulerpa taxifolia invasion.
Marine and Freshwater Research, 58 3 Taxonomic diversity and geographic distributions of aquarium-traded species of Caulerpa Chlorophyta: Caulerpaceae in southern California, USA. CABI, Undated a. CABI, Undated b. In: Database on introductions of aquatic species. Biological Invasions. Marine Ecology, Progress Series. Aquatic Botany. Environment Alert Bulletin, 1, One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Toggle navigation. Datasheet Caulerpa taxifolia killer algae. Don't need the entire report? Generate a print friendly version containing only the sections you need.
Generate report. Expand all sections Collapse all sections. Vahl C. Summary of Invasiveness Top of page C. Notes on Taxonomy and Nomenclature Top of page The genus Caulerpa is thought to contain nearly variable taxa Meinesz, Description Top of page C.
Plant Type Top of page Aquatic. Distribution Top of page C. Distribution Table Top of page The distribution in this summary table is based on all the information available. Illegal to sell but can be kept in enclosed aquaria. Habitat Top of page C. Biology and Ecology Top of page Genetics Meusnier et al. Reproductive Biology The rapid expansion and high abundance of invasive C. Physiology and Phenology C. Environmental Requirements C.
The release of aquarium plants into the natural environment is considered to be the cause for the initial introductions of C. The anchoring of vessels removes fragments of C. Thus, boats may be an important vector for dispersal of C.
Boat traffic across and around the Mediterranean is thought to be the means of spread of this alga from Monaco to Spain, Italy, Croatia and Tunisia. Sport fishing is also considered to aid local movement of C. For these reasons, new infestations tend to occur in ports, harbours and marinas. Economic Impact Top of page Economic and social impacts are due to the reduction in catches of fish by commercial fishermen due to the reduction of fish habitat by C.
A decline in the abundance and condition of a native bivalve Anadara trapezia was associated with C. Gribben and Wright a showed that C. Also, gender specific responses occurred indicating that females were more susceptible to invasion than males Gribben and Wright, a.
However, C. Based on the grazing of four native fishes in Australia, Gollan and Wright concluded that the low diversity and abundance of native herbivores, their weak grazing pressure on C.
Comparing fish populations in two flat marine areas m deep in the Ligurian Sea, Italy, one colonized by C. The high specific richness and the structural complexity in C. Uses Top of page C. Dolin Is. Hvar Is. Elba Is. Imperia Liguria Strait of Messina Toscana. Auckland Region. Mallorca Is. Mediterranean Sea.
Anderson, L. California s Reaction to Caulerpa taxifolia : A model for invasive species rapid response actions. Eradication of Caulerpa taxifolia in the US five years after discovery: are we there yet? Summary: An abstract about the eradication of C. Caulerpa taxifolia: Marine algal invader provokes quick response in U. ANS Digest 4 2 : 13; Summary: Information on the eradication of C.
Taxifolia in California. Boudouresque, C. Scientific papers and documents dealing with the alga Caulerpa taxifolia introduced to the Mediterranean, Ninth edition. Summary: This publication contents the bibliographic references of documents and scientific papers about Caulerpa taxifolia invasion in the Mediterranean Sea.
Carlton, J. Introduced species in U. Pew Oceans Commission, Arlington, Virginia. Summary: An overview of many introduced marine species in the U. Commonwealth of Australia. Environment, Communications, Information Technology and the Arts References Committee: report on the regulation, control and management of invasive species and the Environment Protection and Biodiversity Conservation Amendment Invasive Species Bill Summary: A small amount of information on the cost of eradicating C.
Coquillard, P. Simulation of the mollusc Ascoglossa Elysia subornata population dynamics: application to the potential biocontrol of Caulerpa taxifolia growth in the Mediterranean Sea. Ecological Modelling Summary: Growth, survival, reproduction. Cottalorda, J. Guidelines for the management of invasive alien plants or potentially invasive alien plants which are intended for import or have been intentionally imported.
EPPO Bulletin 36 3 , Gacia, E. Seasonal light and temperatura responses of Caulerpa taxifolia from the northwestern Mediterranean.
Aquatic Botany: Summary: Seasonal light requirements and temperature tolerance of the Mediterranean C. These results indicate that this species is well adapted to light abd temperature typical of the infralittoral and upper circalittoral zone in the Mediterranean. Its annual productivity pattern seems less affected by seasonal fluctiations than has beeb reported for endemic seaweeds; this response may explain its potentially high invasive capacity.
Glasby, T. The spread and attempted control of the invasive seaweed, Caulerpa taxifolia , in New South Wales, Australia. Summary: Information on the use of salting to control C.
Experimental use of salt to control the invasive marine alga Caulerpa taxifolia in New South Wales, Australia. Biological Conservation 4 : , McEnnulty, F. Web publication:. Meinesz, A. Evaluating and disseminating information concerning the spread of Caulerpa taxifolia along the French Mediterranean coasts.
Meinesz A. Summary: Report on the expansion of Caulerpa taxifolia in the Mediterranean coasts at end of 5 countries affected, 99 stations cited, ha concerned, 81 km of coast affected. The report included the cartography of the C. Murphy, N. Caulerpa taxifolia in Australia: A growing problem. Scripps Institution of Oceanography La Jolla, California Summary: Overview of identifcation techniques and a possible framework for the management of future incursions.
Caulerpa taxifolia species summary. National Pest Plant Accord, Biosecurity New Zealand.
0コメント