Starfish Research Papers - Academia.edu (original) (raw)

In the face of ever-increasing threats to coral reef ecosystems, it is essential to understand the impact of natural predators in order to devise appropriate management strategies. Destructive population explosions of the crown-of-thorns... more

In the face of ever-increasing threats to coral reef ecosystems, it is essential to understand the impact of natural predators in order to devise appropriate management strategies. Destructive population explosions of the crown-of-thorns starfish Acanthaster planci have devastated coral reefs throughout the Indo-Pacific for decades. But despite extensive research, the causes of outbreaks are still unclear. An important consideration in this research is that A. planci has been regarded as a single taxonomic entity. Using molecular data from its entire distribution, we find that A. planci is in fact a species complex. This discovery has important consequences for future coral reef research, and might prove critical for successful reef conservation management.

The distribution and population density of Acanthaster planci (crown-of-thorns-starfish or COTS) in Sogod Bay, Southern Leyte, Central Philippines was assessed on July August,2012 using belt transects of 50-80 quadrats (5 x 5 m). Four... more

The distribution and population density of Acanthaster planci (crown-of-thorns-starfish or COTS) in Sogod Bay, Southern Leyte, Central Philippines was assessed on July August,2012 using belt transects of 50-80 quadrats (5 x 5 m). Four sites were considered. Mean COTS density varied significantly among sampling sites, ranging from 0.4-5.2 starfishes/25 m2 corresponding to 160-2,080 starfishes/ha, an indication of an outbreak. On the other hand, the mean body size of A. planci ranged from 13.7 32.4 cm, varied significantly among sampling sites and possibly belonging to different cohorts of COTS population within SogodBay. This suggests that outbreak could be due to progressive accumulation of COTS from multiple cohorts. At Adrian Reef Marine Sanctuary in Limasawa, COTS distributions were aggregated (Morisita’s Index of Dispersion = 2.6) and was significantly larger (32.4 cm) than the other sites. We believe that the aggregation at Adrian Reef Marine Sanctuary is a form of foraging behavior at this time of the year and not a preparation for mass spawning

The response of Acanthaster planci or crown-of-thorns starfish (COTS) to intracoelomic injection of hypersaline solutions was investigated to establish its potential application as A. planci population control especially during an... more

The response of Acanthaster planci or crown-of-thorns starfish (COTS) to intracoelomic injection of hypersaline solutions was investigated to establish its potential application as A. planci population control especially during an outbreak. Adult A. planci when inverted had a normal righting response time (in seconds) of 163 ± 1 (mean ± SE; N ＝ 298). Injection of concentrated salt solutions led to negative effects on adult A. planci. The spines bent down, body collapsed and the starfish became comatose and died after 24-hours. The higher the salt concentration, the higher is the % comatose individuals. In addition, comatose specimens failed to recover with time. Mortality was highest at the highest treatment concentration with LC 90 of 285.3 and LC 99 of 383.2 ppt. The effects of time, salt concentration and its interaction(salt concentration x time) were significant (p ＝ 0.00). Theionic and osmotic disruption of the coelomic fluid canseriously affect physiological functions of the organismincluding neuromuscular activity. Thus, in the control of A. planci, concentrated salt solution can be used as a cheaper alternative to dry acid, acetic acid or m ammoniumhydroxide, all of which are expensive, may not be locally available and not environment friendly

This visual guide is illustrated with images captured by Anadarko Colombia Company (ACC), a subsidiary of Anadarko Petroleum Corporation (APC), during its normal offshore hydrocarbon exploration process at depths between 375 and 3288 m in... more

This visual guide is illustrated with images captured by Anadarko Colombia Company (ACC), a subsidiary of Anadarko Petroleum
Corporation (APC), during its normal offshore hydrocarbon exploration process at depths between 375 and 3288 m in the Colombian Caribbean Sea. Images were taken by towed camera, Remote Operated Vehicle (ROV), and by samples taken in Piston Core projects. Images were classified by large taxonomic groups. National experts were contacted to identify the organisms to the most specific taxonomic level possible. International experts were also contacted to confirm organisms previously identified or to identify those for which no national expert
was available. This guide includes introductions for each major taxonomic group and other ones for more specific groups (if applicable),
provided by the experts themselves, who participated in the identification of the organisms. This is the first visual guide of
deep-sea organisms (mega fauna) for the Colombian Caribbean.

Acanthaster planci commonly known as crown-of-thorns starfish (COTS) is a natural predator of hermatypic corals, and it controls fast growing corals like species of Acropora. However, when the density of COTS on a reef reaches such levels... more

Acanthaster planci commonly known as crown-of-thorns starfish (COTS) is a natural predator of hermatypic corals, and it controls fast growing corals like species of Acropora. However, when the density of COTS on a reef reaches such levels that corals are being consumed faster than they can grow-termed as 'outbreak"-then that is the time to engage in controlling COTS population in order to protect and conserve coral communities where fishing and tourism industry like in the Philippines depends on it. The goal of COTS population control techniques is to regulate COTS population outbreak in developing country like the Philippines using environment-friendly, cheap and safe methods. The process of COTS Population control techniques and management strategies includes: 1) baseline information or assessment of COTS population and distribution including spawning season, 2) coordination, and 3) planning with the different stakeholders including the local government units and business sectors, and 4) implementation of COTS population control techniques using cheap concentrated salt solution using improvised COTS gun that is easy to make and install. The total cost for the first operation is PhP 3492.00 or PhP 2.03/starfish, and this will reduce into PhP 1,160.00 PhP 1.2/starfish in the next operation. This is cheaper than bounty system of PhP 5.00-10.00/starfish in Caohagan Island and Sogod Bay, Southern Leyte and SCUBA Diving using dry acid with Veldspar Spot Gun of about PhP 10,050.00 0r PhP 41.00/starfish for the equipment and dry acid.

“Karavana gelenlere, sandviçler, elmalar ve meyve suyu verdik. Fahişeler, pezevenkler, çocuklar, tamirciler, anneler, büyükanneler, evsizler, uyuşturucu bağımlıları ve uyuşturucu satıcılarına yiyecek dağıttık. Dört saatten sonra yorgun... more

“Karavana gelenlere, sandviçler, elmalar ve meyve suyu verdik. Fahişeler, pezevenkler, çocuklar, tamirciler, anneler, büyükanneler, evsizler, uyuşturucu bağımlıları ve uyuşturucu satıcılarına yiyecek dağıttık. Dört saatten sonra yorgun düşmüş ve kendimi eve atmak için sabırsızlanmaya başlamıştım. (…) Evet, muhtemelen evde yiyecekleri olmadığını bilerek çocuklara yiyecek vermek iyi geldi bana. Ama kimsenin hayatı değişmedi. Hiç kimsenin durumu değişmedi. (…) Ayrıca kendimi karavana gelen insanlardan ayırdığımı, “biz ve onlar” ayrılığının ortaya çıktığını hissettim. ONLAR karavana geldiler, BİZ onlara yiyecek verdik. Sonra ONLAR gitti, BİZ gittik. Bazen aramızda gelişigüzel konuşmalar oldu. Bazıları hasmaneydi. Fakat hiçbiri anlamlı bir sohbet değildi.” (Strain, 2007).

The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very few Konservat-Lagerstätten known so far in the world to have yielded numerous remains of Late Ordovician softbodied fossils associated with... more

The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one
of the very few Konservat-Lagerstätten known so far in the world to have yielded
numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.

Acanthaster planci, the crown-of-thorns starfish, naturally endowed with the numerous toxic spines around the dorsal area of its body. Scientific investigations demonstrated several toxico-pharmacological efficacies of A. planci such as,... more

Acanthaster planci, the crown-of-thorns starfish, naturally endowed with the numerous toxic spines around the dorsal area of its body. Scientific investigations demonstrated several toxico-pharmacological efficacies of A. planci such as, myonecrotic activity, hemorrhagic activity, hemolytic activity, mouse lethality, phospholipase A2 (PLA2) activity, capillary permeability-increasing activity, edema-forming activity, anticoagulant activity and histamine-releasing activity from mast cells. The present study was performed to evaluate the cytotoxic activity of A. planci extracts obtained by different methods of extraction on MCF-7 and HCT-116, human breast and colon cancer cell lines, respectively. Results of the cell proliferation assay showed that PBS extract exhibited very potent cytotoxic activity against both MCF-7 and HCT-116 cell lines with IC(50) of 13.48 μg/mL and 28.78 μg/mL, respectively, while the extracts prepared by Bligh and Dyer method showed moderate cytotoxicity effec...

Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants,... more

Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant–herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore–plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with greater reductions in plant abundance compared with invasive herbivores and invasive plants, native herbivores and invasive plants, native herbivores and mixed-nativeness plants, and native herbivores and native plants. By contrast, assemblages comprised of native herbivores and invasive plants were associated with lower reductions in plant abundance compared with both mixed-nativeness herbivores and native plants, and native herbivores and native plants. However, the effects of herbivore–plant nativeness on changes in plant abundance were reduced at high herbivore densities. Our mean reductions in aquatic plant abundance are greater than those reported in the literature for terrestrial plants, but lower than aquatic algae. Our findings highlight the need for a substantial shift in how biologists incorporate plant–herbivore interactions into theories of aquatic ecosystem structure and functioning. Currently, the failure to incorporate top-down effects continues to hinder our capacity to understand and manage the ecological dynamics of habitats that contain aquatic plants.

LARGE aggregations of the crown-of-thorns starfish Acanthaster planci L have destroyed a high proportion of the coral on certain Indo-Pacific reefs. We report that gamete release by one A. planci induces other ripe starfish to spawn;... more

LARGE aggregations of the crown-of-thorns starfish Acanthaster planci L have destroyed a high proportion of the coral on certain Indo-Pacific reefs. We report that gamete release by one A. planci induces other ripe starfish to spawn; similar behaviour has been observed in ...

Acanthaster planci or Crown-Of Thorns (COTs) population outbreak is one of major threads for coral reef ecosystem. Mostly people used inorganic chemical and still limited research of using organic chemical to control the outbreak. An... more

Acanthaster planci or Crown-Of Thorns (COTs) population outbreak is one of major threads for coral reef ecosystem. Mostly people used inorganic chemical and still limited research of using organic chemical to control the outbreak. An experiment was conducted underwater using SCUBA dive on Bidong Island on 17th August 2014 to 26th August 2014 as aim to examine the physiological response and determine the mortality rate of COTs caused by organic and inorganic chemical. The experiment use four chemical treatments namely control, sodium chloride, hydrochloric acid and citric acid on five samples of A. planci for each treatment. A. planci was injected with 10mL according to the treatment and observed for five days for observation of the experiment. No injection was given to control treatment. Five physiological responses were recorded and discussed namely hyperactivity, mucus production, matting and loss of spines, loss turgor and swelling and blister, lesions, necrosis and expose of organ. The results were HCl achieved 100% mortality within 24 hours, NaCl achieved 20% of mortality on 72 hour and citric acid achieved 40% of mortality on 24 hours of post-injection. Each chemical treatment has their own advantages and limitation in the used in the experiment and on the field to control the outbreak. Recommendations should be consider to improve better precision of result for future further study.

The cause(s) of primary outbreaks of the coral-eating crown-of-thorns starfish (Acanthaster planci) are still subject to scientific controversy. The possibility of primary outbreaks being linked to terrestrial runoff has been postulated a... more

The cause(s) of primary outbreaks of the coral-eating crown-of-thorns starfish (Acanthaster planci) are still subject to scientific controversy. The possibility of primary outbreaks being linked to terrestrial runoff has been postulated a number of times, suggesting that enhanced nutrient supply is critical for enhanced A. planci larval development. This paper examines the evidence for such a cause, focussing particularly on the Great Barrier Reef (GBR). Nutrient discharges from rivers have increased at least four-fold in the central GBR over the last century, and concentrations of large phyto-plankton (>2 μm) of the inshore central GBR shelf in the wet season when A. planci larvae develop, is double that of other places and times. Larval development, growth and survival increase almost ten-fold with doubled concentrations of large phyto-plankton. This and other lines of evidence suggest that frequent A. planci outbreaks on the GBR may indeed be a result of increased nutrient delivery from the land.

Larval and juvenile nervous systems (NS) of three asterinid sea stars with contrasting feeding and nonfeeding modes of development were characterized using the echinoderm-specific synaptotagmin antibody. In the feeding bipinnaria and... more

Larval and juvenile nervous systems (NS) of three asterinid sea stars with contrasting feeding and nonfeeding modes of development were characterized using the echinoderm-specific synaptotagmin antibody. In the feeding bipinnaria and brachiolaria larvae of Patiriella regularis, the species with ancestral-type development, an extensive NS was associated with the ciliary bands (CBs) and attachment complex. Lecithotrophic planktonic (Meridastra calcar) and benthic (Parvulastra exigua) brachiolariae lacked CBs and the associated NS, but had an extensive NS in the attachment complex. The similarity in the distribution and morphology of synaptotagmin immunoreactive neurons and the anatomy of the NS in the attachment complex of these closely related sea stars suggests conservation of neurogenesis in settlement-stage larvae regardless of larval feeding mode. Nerve cells were prominent on the brachia of all three species. In advanced brachiolariae the larval nervous system was localized to t...

Meiotic maturation stimulates a change in the translation of stored mRNAs: mRNAs encoding proteins needed for growth of oocytes are translated before meiotic maturation, whereas those encoding proteins required for cleavage are translated... more

Meiotic maturation stimulates a change in the translation of stored mRNAs: mRNAs encoding proteins needed for growth of oocytes are translated before meiotic maturation, whereas those encoding proteins required for cleavage are translated after meiotic maturation. Studies of translational regulation during meiotic maturation have been limited by the lack of translationally active cell-free supernatants. Starfish oocytes are ideal for preparing cell-free translation systems because experimental application of the hormone 1-methyladenine induces their maturation, synchronizing meiosis. We have prepared such systems from both immature and mature oocytes of starfish. Changes in protein synthesis rates and the specificity of proteins synthesized in these cell-free translation supernatants mimic those seen in vivo. Supernatants both from immature and mature oocytes have a high capacity to initiate new translation because 90% of the proteins made are newly initiated from mRNAs. Cell-free s...

Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it... more

Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataform...

1. Tagging animals is essential to evaluate animal population dynamics and behaviour. Using unique marks requires that tags must last for the duration of the study and not affect animal behaviour and health. Echinoderms, especially... more

1. Tagging animals is essential to evaluate animal population dynamics and behaviour. Using unique marks requires that tags must last for the duration of the study and not affect animal behaviour and health. Echinoderms, especially smaller species, are usually considered intractable for tagging because they readily discard both internal and external tags.
2. We compared the utility of two tagging techniques for marking the small starfish Parvulastra exigua: (i) branding with a soldering iron, and (ii) injection of visible implant elastomer (VIE) of different colours. The efficiency of these techniques was evaluated by assessing (i) the effects of the tag on the mortality, growth and mobility of P. exigua; and (ii) the persistence of the tags over 30 days.
3. VIE had no detectable effect on any variable tested, whereas brand marks caused a decrease in mobility. In addition, 95% of the starfish tagged with VIE were still tagged after 1 month.
4. This technique will facilitate research on the ecology of this and other small asteroid species, and is also relevant for ecological studies of other small soft-bodied invertebrates. The combination of VIE colours plus the viability to track individuals offers a wide range of opportunities to investigate the ecology and behaviour of small invertebrates in the field.

The phototactic behavior of COTS to steady and flashing LED light spectra such as blue (473nm), yellow (595nm), red (625nm) and white was observed/ monitored using infrared closed circuit television (CCTV) camera. Steady LED light spectra... more

The phototactic behavior of COTS to steady and flashing LED light spectra such as blue (473nm), yellow (595nm), red (625nm) and white was observed/ monitored using infrared closed circuit television (CCTV) camera. Steady LED light spectra had a significant effect on the locomotion rate of COTS (ANOVA; p<0.05) and there was no significant effect using flashing LED light spectra (ANOVA; p>0.05). COTS can be considered to be positively phototactic to steady blue spectrum (473 nm) with mean locomotion rate of 30.35 cm/min and negatively phototactic to steady white light with mean locomotion rate of 28.44 cm/min. Blue and white LED can act as photo stimulant either as attractant or repellent to crown-of-thorns starfish.

Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemistry and... more

Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemistry and bioactivity of compounds isolated from all kinds of starfish to illustrate the chemodiversity and biological significance of these constituents, along with their geographical distribution where it is discernible.

Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it... more

Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataform...

The feeding ecology of the brooding sea star Anasterias minuta within tide pools was examined in Central and South Patagonia. 8 470 observations of sea stars were made. A. minuta does not feed while brooding. It consumes a wide range of... more

The feeding ecology of the brooding sea star Anasterias minuta within tide pools was examined in Central and South Patagonia. 8 470 observations of sea stars were made. A. minuta does not feed while brooding. It consumes a wide range of prey, including molluscs and crustaceans, and can be regarded as a generalist
or opportunistic predator. The purple mussel Perumytilus purpuratus was the most abundant prey item (57.6%). Other important prey were the gastropod Pareuthria plumbea, the isopod Exosphaeroma lanceolatum and the mussels Aulacomya atra atra and Mytilus edulis platensis. The proportion of sea stars feeding on sessile prey increases with sea-star size. A significant positive correlation was found between the size of the sea star and the size of the most frequent prey. The diet was fairly constant throughout the year, but diet composition differed between sites, shore level and sea-star size. The diversity of prey consumed by A. minuta was highest on the semi-exposed coast of Caleta Cordova Norte during the temperate season on the infralittoral fringe. A. minuta does not eat prey in proportion to its abundance beneath rocks within tide pools at the infralittoral fringe. Generally, the sea star consumed P. purpuratus and the gastropod P. plumbea more than other prey, even when they were not the most abundant prey present. At the midlittoral zone of the semi-exposed coast of Caleta Cordova Norte, the sea star feeds on prey species accordingly to their abundance. Larger P. purpuratus and E. lanceolatum were eaten disproportionately more often. A. minuta may have an opportunistic feeding strategy, taking unattached, wave-washed mussels when available rather that attached mussels. Consequently, it may have a variable impact on the community structure.

Regeneration is a post-embryonic developmental process that ensures complete morphological and functional restoration of lost body parts. The repair phase is a key step for the effectiveness of the subsequent regenerative process: in... more

Regeneration is a post-embryonic developmental process that ensures complete morphological and functional restoration of lost body parts. The repair phase is a key step for the effectiveness of the subsequent regenerative process: in vertebrates, efficient re-epithelialisation, rapid inflammatory/immune response and post-injury tissue remodelling are fundamental aspects for the success of this phase, their impairment leading to an inhibition or total prevention of regeneration. Among deuterostomes, echinoderms display a unique combination of striking regenerative abilities and diversity of useful experimental models, although still largely unexplored. Therefore, the brittle star Amphiura filiformis and the starfish Echinaster sepositus were here used to comparatively investigate the main repair phase events after injury as well as the presence and expression of immune system and extracellular matrix (i.e. collagen) molecules using both microscopy and molecular tools. Our results sho...

Relationships within the class Asteroidea have remained controversial for almost 100 years and, despite many attempts to resolve this problem using molecular data, no consensus has yet emerged. Using two nuclear genes and a taxon sampling... more

Relationships within the class Asteroidea have remained controversial for almost 100 years and, despite many attempts to resolve this problem using molecular data, no consensus
has yet emerged. Using two nuclear genes and a taxon sampling covering the major asteroid clades we show that non-phylogenetic signal created by three factors - Long Branch
Attraction, compositional heterogeneity and the use of poorly fitting models of evolution – have confounded accurate estimation of phylogenetic relationships. To overcome the effect
of this non-phylogenetic signal we analyse the data using non-homogeneous models, site stripping and the creation of subpartitions aimed to reduce or amplify the systematic error,
and calculate Bayes Factor support for a selection of previously suggested topological arrangements of asteroid orders. We show that most of the previous alternative hypotheses
are not supported in the most reliable data partitions, including the previously suggested placement of either Forcipulatida or Paxillosida as sister group to the other major branches.
The best-supported solution places Velatida as the sister group to other asteroids, and the implications of this finding for the morphological evolution of asteroids are presented.