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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 26 Ago 2014, 16:13 
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https: Video from : https:


https://www.youtube.com/watch?v=tOmfIPkb2DY


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 06 Set 2014, 20:14 
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Peço desculpas se por alguma razão minha pergunta seja inconveniente, mas não vejo mais o ELDER, propositor desse post, falando aqui pelo Brasil Reef, aconteceu alguma coisa com ele ????

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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 25 Nov 2014, 14:15 
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Oi Elder, amigo você poderia me ajudar?
Tenho uma bbt ponta verde que precisei tira la de onde estava pois estava entre duas rochas e uma deslisou e a anemona q ficou segurando... aí tive q soltar ela da rocha q caiu pra volta lá no lugar mas ela (bbt) se soltou da outra tbm e agora está totalmente contraída e não gruda em mais nada e muito menos abre oque eu faco?


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 16 Jan 2015, 01:17 
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Parabéns pelo ótimo post! pretendo ter BBTs, e gostaria se possível, saber as cores encontradas aqui no Brasil. Obrigado desde já!.

existem tamanhos diferentes, tipo bbt anã etc?
abertas que diâmetro possuem aproximadamente, pois possuo um boyu tl-550 de 128 litros apenas!.

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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 02 Mai 2015, 22:11 
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Excelente topico!

Gostaria de tirar uma duvida...

Quando a anemona chega no aquario, posso prende-la de alguma forma durante as primeiras duas semanas pra que nao fique vagando pelo tanque??


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 04 Mai 2015, 09:52 
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Acho que isso não seja aconselhável, ela anda para procurar o melhor lugar.


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 04 Jul 2016, 13:11 
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Pessoal, To pesquisando e bastante interessado em por a primeira anêmona no meu reef mas sou bem iniciante ainda, além das orientações que geraram esse tópico. Como devo acompanhar os parâmetros magnésio e cálcio e o que fazer caso saiam do ideal, identificar possíveis doenças, se uma bbt é anã ou não, pra não cair na armadilha que nosso amigo caiu e outras coisas que eu precise saber mas não coloquei na pergunta por falta de conhecimento?

Obrigado a todos e ótimo tópico


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 04 Jul 2016, 13:43 
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BBT ana vc identifica pelo proprio tamanho sao pequenas

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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 05 Jul 2016, 15:07 
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Sim mas se eu comprar bbt e ela ainda não tiver o tamanho que a diferencie como eu saberei na assim que a ver na loja?


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 08 Jul 2016, 08:48 
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Se tiver duvidas em relacao a isso devido ao tamanho nem compre.

As bbt anas costumam ser menos coloridas, mas isso nao é referencia. Outra coisa q sao muito baratas, mas nao impede q o vendedor tente passar a perna.

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 Título: Re: Desmistificando as BBT - guia rápido e prático
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Muito bom o seu tópico fera! Adorei. Como sou iniciante, procuro o máximo de informação possível. À propósito, gostaria de saber se a existência de alga verde na rocha constitui um empecilho para que ela se fixe.
Grato pela atenção!


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 Título: Re: Desmistificando as BBT - guia rápido e prático
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Em relação a temperatura, quando se fala que, se chegar a 30ºC elas aguentarão, mas não por muito tempo, estamos falando de quanto tempo? Horas, um dia?


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 Título: Re: Desmistificando as BBT - guia rápido e prático
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Minhas BB, atualmente :

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Imagem
Dimensionando o UV
- Passagem correta de água pelo filtro UV: 15 litros/hora por watt da lâmpada.
- Necessário se faz a passagem de no mínimo 2 vezes o volume total do aquário pela lâmpada/dia


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 Título: Re: Desmistificando as BBT - guia rápido e prático
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Mauro Becker escreveu:
Minhas BB, atualmente :

lindas.... icon_iCo01

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Andrés Segal / Campínas / SP

Atual 1000 litros : http://brasilreef.com/viewtopic.php?f=2&t=31842
Desmontado e Vendido 200 litros: http://brasilreef.com/viewtopic.php?f=25&t=18696 - TRANCADO
PS. Não mate a formiga, ela é um GIF animado....


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 Título: Re: Desmistificando as BBT - guia rápido e prático
MensagemEnviado: 29 Mai 2019, 22:27 
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Boa noite pessoal.

Segue estudo sobre a reprodução sexuada e assexuada das anêmonas.
Interessante foi que salinidade baixa provoca mais divisões.

Reference: BiD!. Bull. 182: 169-176. (April, 1992)
The Culture, Sexual and Asexual Reproduction, and Growth of the Sea Anemone Nematostella vectensis
CADET HAND AND KEVIN R. UHLINGER
Bodega Marine Laboratory, P.O. Box 247, Bodega Bay, California 94923
Abstract. Nematostella vectensis, a widely distributed, burrowing sea anemone, was raised through successive sexual generations at room temperature in non-circulating seawater. It has separate sexes and also reproduces asex- ually by transverse fission. Cultures of animals were fed Artemia sp. nauplii every second day. Every eight days the culture water was changed, and the anemones were fed pieces of Mytilus spp. tissue. This led to regular spawning by both sexes at eight-day intervals. The cultures remained reproductive throughout the year. Upon spawning, adults release either eggs embedded in a gelat- inous mucoid mass, or free-swimming sperm. In one ex- periment, 12 female isolated clonemates and 12 male iso- lated clonemates were maintained on the 8-day spawning schedule for almost 8 months. Of the female spawnings, 750/0 occurred on the day following mussel feeding and water change, and 640/0 of the male spawnings were sim- ilarly synchronized under this regime. Fertilization and development occur when gametes from both sexes are combined in vitro. At 20°C, the embryos gastrulate within
12-15 hours. Spherical ciliated planulae emerge from egg masses 36-48 hours post-fertilization. The planulae elon- gate and form the first mesenteric couple, as well as four tentacle buds, by day five. By day seven, they metamor- phose and settle as 250-500 Jl-m long, four-tentacled ju- venile anemones. More tentacles and all eight macro- cnemes are present at 2-3 weeks. Individuals may become reproductively mature in as few as 69 days. Nematostella vectensis has the potential to become an important model for use in cnidarian developmental research.
Introduction
Many sea anemones can be maintained for long periods under a variety of conditions including non-circulating
water at room temperatures (Stephenson, 1928), and un- der the latter conditions some species produce numerous asexual offspring by a variety of methods (Cary, 1911; Stephenson, 1929). More recently this trait has been used to produce clones ofgenetically identical individuals use- ful for experimentation; i.e., Haliplanella luciae (by Min- asian and Mariscal, 1979), Aiptasia pulchella (by Muller- Parker, 1984), and Aiptasia pallida (by Clayton and Las- ker, 1984). We now add one more species to this list, namely Nematostella vectensis Stephenson (1935), a small, burrowing athenarian sea anemone synonymous with N. pellucida Crowell (1946) (see Hand, 1957).
Nematostella vectensis is an estuarine, euryhaline member ofthe family Edwardsiidae and has been recorded in salinities of 8.96 to 51.54%0 and water temperatures of -1 ° to 28°C (Williams, 1983). It is a small animal, usually less than 2 cm long and a few millimeters in diameter when found in the field (Williams, 1983). It occurs in England, from Nova Scotia to Georgia on the North American Atlantic coast, from Florida to Louisiana along the shores of the Gulf of Mexico, and from California to Washington on the Pacific coast (Hand, unpub. Louisiana record; Heard, 1982; Kneib, 1985; Williams, 1983). Wil- liams (1983) considered the species vulnerable to extinc- tion in Great Britain, but it is plentifully abundant throughout most ofits range and is readily collected. Ne- matostella occurs in soft sediments, in plant debris, and among living plants in permanent pools and tidal creeks in salt marshes. It also occurs subtidally in estuaries in Chesapeake Bay (M. Posey, pers. comm.; Calder, 1972) and in the Indian River in Delaware (Jensen, 1974).
To date we have only the barest outline ofthe life history of this species. Crowell (1946) and Frank and Bleakney (1976) reported that eggs were discharged in mucoid masses accompanied by numerous nematosomes. Ne- matosomes, which occur in the coelenteron, are spherical,
Received 25 July 1991; accepted 13 January 1992.
15-45 #m, flagellated bodies containing nematocysts and
169

170 C. HAND AND K. R. UHLINGER
are known only from the genus Nematostella (Williams, 1979). Frank and Bleakney (1976) reported that planula larvae developed from the eggs, but subsequently disap- peared, and Williams (1975) found three, 1.0 mm long planulae that he attributed to Nematostella in a pool con- taining that sea anemone. Rudy and Rudy (1983) kept N. vectensis in the laboratory for five years and stated that eggs developed to planulae in three days and to' "four- knobbed" juveniles, i.e.,' with four tentacle buds, in five days. The sexes are separate (Hand, 1957; Frank and Bleakney, 1976; Williams, 1975), and N. vectensis repro- duces asexually by transverse fission (Lindsay, 1975; Wil- liams, 1976; Frank and Bleakney, 1978).
Even less is known about the natural history of N. vec- tensis. Kneib (1985) has shown that the grass shrimp Pa- laemonetes pugio may prey on this anemone, and Lindsay (1975) and Frank and Bleakney (1978) have given us in- formation on the anemone's diet. We also know that it tolerates extremes of temperature and salinity (Bleakney and Meyer, 1979; Stephenson, 1935) and, at times, may occur in dense populations, i.e., over 5 million in a single pool (Williams, 1983) and 1816 in a 15 cm2 sample (Bleakney and Meyer, 1979). Little beyond this is known of its natural history.
Here we describe the culture, reproduction, develop- ment, and growth of Nematostella, as well as some other aspects ofits biology. In particular, we show that this ane- mone reproduces sexually in standing water at room tem- perature, is readily raised through successive generations, is sexually active throughout the year, and shows no sign of seasonality in its reproduction in the laboratory. This combination of traits-namely asexual reproduction, which allows the development of clones, and sexual re- production with subsequent development through larval stages to reproductive adults, all under room temperature culture conditions-suggests that this sea anemone should be useful in the study of cnidarian biology, particularly development.
Materials and Methods
In December 1987, we received 12 living N. vectensis that had been collected subtidally from the Rhode River, a subestuary of the Chesapeake Bay in Maryland. The largest of these anemones was about 15 mm long when fully extended. The salinity at the time and place of col- lection was about 12%0. These Rhode River anemones, together with their sexual and asexual descendants, have been maintained in our laboratory and now number sev- eral thousand. It is from these cultures that isolated female and male clonemates were reared (see below). We also have cultures ofNematostella from England, Nova Scotia, Georgia, California, Oregon, and Washington.
Culture methods
Our cultures were maintained in crystallizing dishes with plastic Petri dish parts as covers. They were kept at room temperatures ranging from 16-26°C, and at a sa- linity of about 12roo. We did not provide these animals with any substrate, such as silt or fine sediments, nor did we provide aeration to the cultures. The water was changed weekly to bi-weekly, but solitary anemones or cultures of only a few individuals may actually be kept for several weeks in unchanged water. Nematostella will tolerate crowding. We have raised about 300 sea anemones to lengths of 2-4 cm in a single 80 X 40 mm dish con- taining 100 ml of water, and we have reared equal num- bers from planulae to young sea anemones, about 1.0 cm long, in 25 ml of water in 51 X 31 mm dishes.
We fed Artemia nauplii to our cultures every second day, and cultures have been maintained for more than two years on that diet alone; we have used both San Fran- cisco Bay Brand and Sanders Premium Great Salt Lake Artemia. Other foods used were the yolk of hard boiled hens' eggs and veliger larvae of mussels and oysters. These are readily accepted by recently metamorphosed sea ane- mones. Tissues from Mytilus edulis and M. cali/ornianus, such as the ovary cut into 1-2 mm pieces, are also readily eaten by larger Nematostella.
The production ofisolatedfemale and male clonemates
The 12 Nematostella received from the Rhode River in December 1987 grew rapidly and began producing fer- tile egg masses in February 1988. From these and sub- sequent spawnings we reared several hundred Nemato- stella to sexual maturity. To observe spawnings more closely and to control the time offertilization, we isolated sibling anemones that were several months old. By April
1989 we had isolated 16 mature and reproductively active females and 14 reproductive males. Each animal was held in a 51 X 31 mm dish containing 25 ml of 33% seawater, and each was fed 3-5 drops ofconcentrated Artemia nau- plii every second day. Each animal was fed small pieces of M. californianus ovary every eighth day, the water in each dish was changed irregularly, and the pattern of spawning was observed.
In time, through asexual reproduction by transverse fission, many of the isolated individuals became clonal groups, and in the period from February 1989 to Decem- ber 1989, one particular isolated male anemone became a clone of 96 individuals and one female became a clone of 38. From these two clones, we isolated 12 female and 12 male clonemates as above. These isolated anemones were fed several drops of nauplii every second day and two pieces ofM. californianus ovary every eighth day fol- lowed by a water change. We recorded spawnings for these anemones from 12 February to 3 October 1990 (Table I).

Effects ofsalinity
Because Nematostella is euryhaline and because it re- produced frequently for us, we explored the effect of sa- linity on both sexual and asexual reproduction. We pre- pared the following concentrations of seawater: 10%, 20%, 33%,66%, 100%, 125%. The salinity ofthe 100% seawater was 34%0, and the 125% seawater was prepared by evap- oration. We selected 6 groups of20 anemones each from a culture of about 300, essentially mature, 6-month-old siblings, 2.0-3.0 cm long. Other than the group of20 that was to stay in 33% seawater, each group was acclimated to the desired final concentration by being successively moved, every four days, through the increasing or de- creasing concentrations. We fed these anemones brine shrimp nauplii every second day, and recorded their sexual and asexual reproduction for a sixteen week period, from mid-October 1988, to the end of January 1989.
Results
Sexual reproduction
In our cultures, anemones become sexually mature at three to four months of age and at column lengths of between 1.5 and 3.5 cm. The sexes are separate, and in- dividuals that have been isolated for more than two years continue on as either males or females. We have seen no signs of hermaphroditism or change of sex. In cultures of mixed sexes, spawning frequently occurred in numerous dishes on a given day; i.e., cultures on comparable feeding regimes tended to spawn at the same time. Egg masses formed within females are extruded through the mouth (Fig. 1). The eggs are opaque and creamy white, and they vary in diameter from 170 to 240 #Lm. The masses consist ofa gelatinous-like material which adheres to nearby ob- jects when first extruded. The masses may be small and spherical (up to about 2 or 2.5 mm diameter) or elongate, and in the extreme, more than 5 cm long by 3 mm in diameter (Fig. 2). There may be few eggs, i.e., 5-10, such as reported by Crowell (1946), or there may be many more (the largest egg masses we have seen contained more than 2000 ova). As well as ova, the egg masses contain hundreds, even thousands, of nematosomes. These can be seen rotating in place within the egg mass. In our cul- tures, sexual reproduction has occurred in every month of the year with no apparent seasonality or correlation with moon phases.
In the first experiment with 16 female and 14 male isolated siblings, we, recorded numerous instances when most of both sexes spawned within a few hours of one another, between mid-afternoon and early evening. Fe- males produced from one to three egg masses each spawning, and males released varying amounts ofsperm.
In the second experiment, with 12 female and 12 male isolated clonemates, we recorded 322 female and 264 male
spawnings; 242 of those by females and 170 of those by males occurred the day after both sexes had eaten mussel and had had their water changed (Table I). Thus 75% of the female spawnings and 64% of the male spawnings occurred on the same days and, as before, within a few hours of one another. Of those spawnings, all 12 females spawned in seven cases, and all 12 males spawned in four. On three occasions, all 12 of both sexes spawned on the same day. On the day after eating mussel, at least one female always spawned, but on three occasions, no male spawned.
Embryology and development
Sperm produced by isolated males can be added to ex- truded egg masses and development observed. Cleavage leads to translucent blastulae, most of which become in- vaginate gastrulae 12-15 hours after fertilization at around 20°C (Fig. 3). The gastrulae emerge from the egg mass as 200-250 ~m spherical, ciliated planulae 36-48 hours after fertilization. The planulae alternate between periods of swimming and resting and develop an apical tuft oflarge cilia that becomes obvious by the third day. They change their shape progressively from spherical, to pear-shaped, to elongate, and by five days, some develop four tentacle buds around the mouth (Figs. 4, 5). At four to five days, there are two thickened areas oftissue internally that rep- resent the first mesenteric couple. By the seventh day, many planulae cease swimming, settle to the bottom, and metamorphose into 250-500 #Lm long juveniles with four tentacles. The metamorphosed young may retain cilia on their columns for more than a month and grow to a length of more than 1 mm before the cilia are lost. During the first few days after metamorphosis, the juveniles glide over the substrate with the aboral end forward, although they no longer rotate about their longitudinal axes as the plan- ulae did. The direction of movement reverses after a few days, and the juveniles then glide with the oral end leading. Most juveniles cease gliding before they are 1 mm long.
The young anemones vary considerably in size, and by 10 days some may already be 1 mm long when fullyex- tended. By two weeks some will have grown to 2 mm (Fig. 6), by three weeks to 4 mm or slightly longer, and, in the extreme, to 2.5 cm long in a month. At 2-3 weeks, a second set of four tentacles develops, and all eight ma- crocnemes are obvious, although the first couple are much
larger than any ofthe others. This seeming dominance of the first mesenteric couple is a feature that remains ob- vious for the first several months. Commonly, month-old animals have 12 tentacles, can extend their bodies to 1- 2 cm, and possess a few nematosomes. Two-month-old animals are approaching sexual maturity, are 2-5 cm long, may have 16 tentacles, and have usually developed abun- dant nematosomes. Some mature sexually and spawn at
CULTURE OF NEMATOSTELLA 171

172 C. HAND AND K. R. UHLINGER

an age of about 10 weeks. Spawning occurred in one cul- ture that was only 69 days post fertilization. Asexual di- vision by transverse fission also becomes common at about 10 weeks. The earliest fission noted was in a seven-week- old individual that was almost 3 cm long. In about five months, heavily fed animals can grow to expanded lengths exceeding 16 cm, with physal diameters of4-5 mm, and tentacles 2-3 cm long.
In every group of developing sea anemones, we have observed variations in timing and size ofindividuals. Not all planulae metamorphose to juveniles in seven days, and some delay metamorphosis for at least two weeks. In one instance, planulae remained active for as long as 135 days, and in that time their size decreased such that the last one measured, just six days before it was last seen, was about 100 ~m long. Frequently a few planulae, 10/0 or less, remain active for 1-2 months in bowls with their developing siblings, but we do not know whether these are still capable of metamorphosing.
As well as variations in growth rates, we have observed newly metamorphosed juveniles with two and three ten- tacles rather than the normal four. At ages of several months to a year or more, there may be large variations in the abundance ofnematosomes. Too, some individuals have large physal regions or very long tentacles compared to others, and the frequency ofasexual reproduction varies greatly from individual to individual. There also may be much variability in planular size, because the planulae in our cultures seldom exceed 500 ~m long, a size substan- tially less than those reported by Frank and Bleakney (1976) and Williams (1975).
Nematosomes
Nematosomes are equally abundant in both sexes. Those embedded in the egg masses emerge from the ma- trix along with the emerging planulae. They do not move throughout the water column, but tend to remain rotating near the degenerating matrix of the original egg mass. However, both the egg mass matrix and the nematosomes may remain in the dish with the developing anemones for extended periods. We have had nematosomes remain
active for as long as 13 days past the date of spawning, and the gelatinous matrix from the egg mass, although shrinking in size, may remain for a month or more.
Other populations
We have kept cultures from areas other than Chesa- peake Bay on feeding and water changing schedules iden- tical to those from Chesapeake Bay. These cultures also tend to spawn synchronously with those from Chesapeake Bay. The development, metamorphosis, and growth of the offspring ofthose cultures do not differ from those of the Chesapeake Bay anemones.
Salinity
The anemones in 10% and 200/0 seawater did not do well; we terminated these two cultures at 5 weeks because 18 of the 20 in 100/0 seawater, and 13 of the 20 in 200/0 seawater, were deflated and had mesenteries everted through their mouths. There had been one asexual divi- sion in the group in 200/0 seawater. The anemones in the other salinities all produced fertile egg masses and planula larvae, and all planulae, except those in 1250/0 seawater, metamorphosed to young anemones. At the end of 16 weeks (Table II), we discontinued this study. The ane- mones in 330/0 seawater had grown to be 4-6 cm long, had spawned four times, and by asexual reproduction had become a group of 29 anemones. The group in 660/0 sea- water did not grow much, and were barely larger than at the initiation ofthe experiment. These had spawned four times and had become a group of 28 animals. The ane- mones in 1000/0 seawater had decreased in size, the largest being about 2.5 cm long when fully extended. These ane- mones had become a group of 26 and had spawned only once. The anemones in 1250/0 seawater also only spawned once, had become a group of 22, and decreased in size,
the largest being about 2.0 cm long. Discussion
Nematostella vectensis is regarded as a small sea ane- mone, and Williams (1983) stated that, although they may
CULTURE OF NEMATOSTELLA 173
Figure 1. Spawning female releasing part of an egg mass. Note the remaining unreleased egg mass in colenteron at the arrow. Scale bar: 1.0 em.
Figure 2. Egg masses from numerous individuals collected from one evening's spawn. Scale bar: 1.0 em.
Figure 3. Blastulae, early gastrulae and nematosomes in situ in an egg mass fertilized 14 hours earlier. Arrow points to a nematosome. Scale bar: 100 ILm.
Figure 4. Three day post-fertilization planula with early apical tuft. Scale bar: 100 ILm.
Figure 5. Five day post-fertilization planula with fully developed apical tuft and developing tentacle buds. Tentacle bud at arrow. Scale bar: 100 ILm.
Figure 6. Two-week-old, four tentacled juvenile anemone. Arrow points to one member of the first couple of mesenteries. Note its size compared to the adjacent smaller primary mesenteries. Scale bar: 1.0mm.

174 c. HAND AND K. R. UHLINGER Table I
Spawning of12 isolatedfemale and 12 isolated male clonemates of Nematostella vectensisfrom 12 February to 3 October 1990 Females
Number of spawns of anemone
Dayofspawn 2 3 4 5 6 7 8 9 10 11 12 spawns %
Daybeforeeatingmussel342312423314 32 10 Dayofeatingmussel 100010000011 4 1
Day after eating mussel Otherdays
Sum
Dayofspawn
20 18 20 21 21 22 19 21 21 19 19 21 242 75 335435327324 44 14 27 25 27 28 26 29 26 25 31 25 23 30 322 100
Males
Number of spawns of anemone
2 3 4 5 6 7 8 9 10 11 12 spawns %
Daybeforeeatingmussel 0 0 1 0 0 0 0 1 0 0 0 0 2 1 Dayofeatingmussel 626645637583 61 23
Day after eating mussel Otherdays
Sum
16 13 15 12 16 15 11 13 11 17 16 15 170 64 152102265142 31 12 23 20 24 19 20 22 19 23 23 23 28 20 264 100
All anemones were fed brine shrimp nauplii every second day. Each eighth day they were fed pieces of Mytilus californianus ovary and the water was changed. All were mature, 6-10 cm long adults at the initiation of the test and were maintained in 33% seawater.
be up to 6 cm long, they are usually less than 2 cm. We were surprised, therefore, when our laboratory specimens grew to more than twice the maximum size reported pre- viously. All earlier size measurements appear to have been made on recently collected animals, and not well-fed cul- tured ones. The small size of the sea anemones in the field, relative to the larger sizes in our cultures, must reflect the small amount of food they capture in their native habitats.
The production of gelatinous egg masses by Nemato- stella is a unique feature of this sea anemone, although the eggs ofHalcampa duodecimcirrata, which are released individually, become surrounded by ajelly envelope after fertilization (Nyholm, 1949). The jelly attaches the eggs to the sandy bottom in which Halcampa lives.
We know of no other sea anemone that spawns re- peatedly over extended periods, although an annual period ofreproductive activity is known for many sea anemones (Jennison, 1979). N. vectensis may well have an annual reproductive cycle in nature; but in the laboratory it has spawned repeatedly and on a predictable schedule. We have tried feeding mussel tissue every fourth day to some female clonemates ofthe anemones on the eight-day cycle. The results led to spawns in an erratic and unpredictable fashion; apparently N. vectensis cannot spawn repeatedly at four-day intervals. We now are attempting a seven-day cycle, and early results suggest that predictable spawnings will occur at seven-day intervals.
How the reproductive cycle of N. vectensis operates in nature is unknown. Most populations of this anemone
Table II
Asexual reproduction, growth, and spawning during 16 weeks in various concentrations ofseawater
Sea water Initial Final concentration number number
33% 20 29
66% 20 28 100% 20 26 125% 20 22
Largest final size
6.0cm 3.5 cm 2.5 cm 2.0cm
Number of spawns
Larvae metamorphosed
All anemones were 2.0-3.0 cm long, six-month-old siblings at the initiation of the experiment. All were fed brine shrimp nauplii every second day, and the water was changed every one to two weeks.
4 yes 4 yes 1 yes 1 no
Total
Total

live in pools in marshes at tidal elevations that do not necessarily receive fresh water with each tidal cycle, and their food consists of denizens of the pools they inhabit (Lindsay, 1975; Williams, 1976; Frank and Bleakney, 1978). The higher tides generally provide fresh seawater to the pools, and at times that water must carry large amounts of plankton. We wonder whether the pulses of extra food, in the form ofthe mussel ovary that we supply, may mimic pulses of extra food from the plankton that they receive in nature. Perhaps that pulse of food, along with the change of water, is the key to the release of ga- metes in N. vectensis.
The planula larvae ofN. vectensis, from the age ofabout three days onward, are active swimmers, although they do spend long periods immobile on the bottoms of our culture dishes. Some swimming is spontaneous, but ifthe cultures are disturbed, most of the motionless planulae leave the bottom and swim actively. They swim in a clockwise spiral, as viewed from the oral end ofthe plan- ula, and while doing this they rotate around their longi- tudinal axes in a clockwise direction. Widersten (1968) reported similar rotation in several cnidarian larvae, in- cluding several species of sea anemones, although he also observed some anemone planulae that rotated either clockwise or counterclockwise. In contrast to the generally clockwise rotation of the sea anemone larvae, he found only counterclockwise rotation in hydrozoan and scy- phozoan planulae.
The reversal in the direction of gliding by the juvenile anemones was unexpected and is previously unreported. We presume that the same cilia that move the planulae in an aboral direction later reverse their beat and move the recently metamorphosed anemones in an oral direc- tion. But the juveniles could alternatively be propelled by newly developed cilia.
In the only specific study of nematosomes, Williams (1979) found no correlation between the size of an ane- mone and the number ofits nematosomes, and we agree. He also considered nematosomes to be functionless, and although we find that difficult to accept, their function is certainly not obvious. In his study, Williams also showed that nematosomes removed from anemones had relatively short lives; i.e., only those maintained at low temperature (1.5-3.5°C) lived as long as 55 hours. In sharp contrast, we found that nematosomes would live for 13 days outside of the body of anemones at temperatures around 20°C. Williams (1979) made his observations on material in normal seawater (34%0), whereas our material was in a salinity ofabout 12%0. Too, we did not artificially free the nematosomes from the anemones. Our observations were on nematosomes contained in egg masses, from which they emerged along with the planulae.
As we noted earlier, N. vectensis is a euryhaline sea anemone; it can be found in widely varying salinities. Our
own experience in culturing this anemone confirms that we are dealing with a widely tolerant euryhaline, eury- thermal sea anemone, and we know of no other sea ane- mone ofequal tolerance. Not only is N. vectensis tolerant, but it carries out its full repertoire of sexual and asexual reproduction, development, and growth in a wide range of salinities. When cultured in full strength seawater, or higher salinities, growth seems to be inhibited, and we have not observed successful sexual reproduction and subsequent metamorphoses in salinities greater than 34%0.
Sexual reproduction and the subsequent development in sea anemones have rarely been studied (see review by Stephenson, 1928; also Mergner, 1971; Campbell, 1974; and Fautin et al., 1989). Those species that have been reported upon had all been recently collected, brought in to a nearby laboratory or field station, and subsequently spawned. Fortuitously, investigators on the scene, such as Nyholm (1943, 1949), Chia and Spaulding (1972), Sie- bert (1973, 1974), Riggs (1988), and Chia et al. (1989), have been able to examine some of the events from spawning onwards, although until now there have been no reports of rearing of successive generations of any spe- cies. Most studies do not describe development beyond the planula, although those of Spaulding (1972) on Peachia quinquecapitata, Chia and Spaulding (1972) on Tealia crassicornis, and Siebert (1973) on Stomphia di- demon are exceptions. Of all the studies of development of sea anemones, we are aware of only two (Clark and Dewell, 1974; Larkman and Carter, 1984) that have pro- vided a close look at fertilization and related events. Those studies, like the others we have cited on matters related to development, were largely made possible by sponta- neous spawnlngs and not as the result of planned or con- trolled spawnings. Now that we can culture Nematostella throughout its life history and can control some of the variation through the use of clonal anemones, we can look closely and repeatedly at all events, from fertilization to spawning. Moreover, the short generation time of two to three months in laboratory-reared Nematostella will allow ready genetic analyses. Because Nematostella can be cultured away from marine facilities, research on every aspect of its life history can be carried out at inland lab- oratories, and we believe this sea anemone has the poten- tial to become an important model for research in cni- darian biology.
Acknowledgments
Weare grateful to Martin Posey for the material from Chesapeake Bay, and we also owe our thanks to the fol- lowing for other material: Martin Sheader and Daphne Fautin for specimens from England; Sherman Bleakney for specimens from Nova Scotia; R. T. Kneib for speci- mens from Georgia; Edward Lyke, Daniel Wickham, and
CULTURE OF NEMATOSTELLA 175

176 C. HAND AND K. R. UHLINGER
Pamela Roe for specimens from California; Jon Geller for specimens from Oregon; Eugene Kozloff, Edward Lyke, and Claudia Mills for specimens from Washington. We thank Tzyy-ing Chen, Jennifer Russo, and Eleanor Uhlinger for their help in caring for our animals, and we are grateful for the assistance Beth Clark provided in the preparation of our manuscript. Fred Griffin and Eduardo Almeida each provided invaluable assistance with pho- tography and we thank Wallis Clark for the' use of his laboratory's photographic and optical equipment. Com- ments and suggestions from Wallis Clark, Fred Griffin, and Eleanor Uhlinger have been ofgreat assistance in the development of the manuscript. This work is a result of research sponsored in part by NOAA, National Sea Grant College Program, Department ofCommerce, under grant number NA89AA-D-SG138, project number 83-A-N, through the California Sea Grant College. The U.S. Gov- ernment is authorized to reproduce and distribute reprints for governmental purposes.
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