FAU Institutional Repository http://purl.fcla.edu/fau/fauir This paper was submitted by the faculty of FAU’s Harbor Branch Oceanographic Institute. Notice: © 1983 Florida Academy of Sciences. This manuscript is an author version with the final publication available and may be cited as: Jennison, B. L. (1983). Reproductive biology of three species of sea anemones from the central Atlantic coast of Florida. Florida Scientist, 46(3-4), 179-186. r t Academy Symposium REPRODUCTIVE BIOLOGY OF THREE SPECIES OF SEA ANEMONES FROM THE ) CENTRAL ATLANTIC COAST OF FLORIDA BRIAN L. JENNISON 1555 Oxford St., #103, Berkeley, California 94709 I ABSTRACT: Reproductive biology of 3 ,\1Jecies of sea anemones u:as studird over an 8 mo prriod I in the intertidal zone along the central Atlantic coast of Florida. Actinia bermudensis on thr I north ;etty at Fort Pierce Inlet spau:ned at thr end of September 1977: planulae u;ere brooded .. throughout the yr. The sex distribution of 82 animals examined raz.s 41 females, 5 males and 36 1,-ithout gon ads. Aiptasia pallid a from Sebastian Inlrt spatrned in September 1977 and possibly in March 1978; the skerred sex distribution of 134 animaL\· exarnirwd u·as 34 females. 2 males I and 98 without gonad5. Bunodosoma cavernata from the south ictty at Jupiter Inlet spawned in October 1977; planulae were brooded throughout the yr. The sex ratio of 75 animaL~ examined ras closer to one-to-one (19 females, 29 males. 26 lacked gonad~. and 1 hermaphrodite). l 1 r SEA ANEMONES occur in central Florida waters in variety and abundance, but surprisingly little is known of their reproductive biology. Some informa­ r tion may be gleaned from systematic works (McMurrich, 1889; Duerden, 1898, 1902), but in most cases this information is limited to descriptions of the reproductive state of a few specimens under systematic study. Accord­ ingly, during a post-doctoral yr at Harbor Branch Foundation I examined the reproductive biology of 3 species of sea anemones from the Indian River and nearby coastal waters of central Florida. MATERIALS A I'D MITHODS- Nine to 13 (usually 12) individuals of i\ctinia bermuden.sis were collected on 7 occasions between 16 September 1977 and 21 June 1978 from the low intertidal zone along the north jetty at Fort Pierce Inlet. Twelve to 15 individuals of Aiptasia pallida were collected on 3 occa~ions between 20 September 1977 and 13 December 1977 from low intertidal rocks along the north shore of Seba~tian Inlet. 1n 4 further collectiom made between 8 FebruarY 1978 and 6 June 19/R. this number was in creased to between 19 and 26. Between It and 15 in· diYiduals of Bunodosoma cavernata were collected on 6 occasions from 5 October 1977 to 24 ~Ia\ 1978. from the lm' intt>rtidal zont> on the south jetty at Jupiter Inlet . Additionally. 1 specimen was taken at Fort Piercl' Inlet on 16 September 1977. Following collection. anemones of all 3 species were relaxed in 50:50 seawater and isotonic !l.lgCt.. Specimens \\UP cleaned. fix ed in Hollande's fluid, and embedded in paraffin Sections 8-10 11m thick, made through the basal half of the column of each specimen, were mounted, stained with picro-indigo carmine. counterstained with basic fuchsin, and examined and photographed through a compound microscope. To a~sess female maturation in all 3 species, oogonia and ooc~ies from each identifiable female were mea~ured from prepared sections by ocular micrometer. At least 50 gametogenic cells were measured from each female: generally only those cells which had a distinct nucleolus were meamred. to standardize the diameter measurements. as well as to a\'C>id counting the same ooc\·te twice. HoweYer. if fewer than 50 cell s were present in the sections. all of them were measured. regardles.' of presence or absenc·e of a nucleolus. Male maturity was determined bY the presenc<: or absence of gonia! celts and tail~:d sperm (sec Jennison, 1979j. Additional serial st'<'tions were made of seYeral specimens of Actinia lwrmudrmL~ to study brooded planulae in detail. RESULTS- Of 82 specimens of Actinia bermudensis from the north jetty of Fort Pierce Inlet examined, 41 were females, 5 were males and 36 lacked 180 FLORIDA SCIENTIST [Vol. 46 Actima bermudensis N s 12 per collection P =Brooded planulae present (N) f =Spawning P(Gl P(9) P(Sl P(6) P(9l P(IOl P(ll) 400 300 E ~ ... 250 Cil Q; E 200 c 0 ~ 150 >- u 0 0 100 50 30 IOL---~~~~--+----+~--+---~~~~--~---1~--+-~-+--~ 4 9 3 3 II 8 4 Sept Oct. Noll Dec. Jon Feb. Mar. Apr. May Jun. 1977 1978 Ftc. l. Size-frequency histogram of oocyte dia of Actinia b!'rmudensis. N = number of females in sample. P(6) = 6 adults brooding planulae in sample. gonads. A broad range of oocyte sizes was present throughout the yr (Fig. 1). However, it is evident that the largest oocytes (300 /LID dia and larger) began to be present in increasing numbers in the spring and summer. Abrupt spawning occurred between the September 16 and October 12 collections in 1977. Two of 5 males were found on 16 September 1977; 1 on 26 March 1978; and 2 on 21 June 1978. All had apparently ripe gonads, with bulging spermatogenic vesicles and clusters of tailed spermatozoa. No her­ maphrodites were found, nor was there any evidence of asexual reproduc­ tion in this species. Of 75 specimens of Bunodosoma cavernata from the south jetty of Jupiter Inlet, 19 were females, 29 were males, 26 lacked gonads, and 1 appeared to be an hermaphrodite. A chi-square test of females vs. males yielded an x2 value of 1.69 (0.5 < p < 0.1), indicating the sex ratio varied significantly from one-to-one. Five ripe males were seen on 5 October 1977, and 4 spawned-out males containing torn spermatogenic vesicles and residual sperm were seen on 17 November 1977. Very early spermatogonial develop- jiiii> No. 3/4, 1983) JENNISON- SEA ANEMONES 181 ment was observed in 1 anemone on 20 January 1978; in 7 on 15 March 1978; and in 3 on 20 April 1978. By 24 May 1978, tailed sperm were ob­ served in 4 anemones, indicating that the population was again becoming ripe (see Jennison, 1979 and 1981 for discussions of spermatogenesis in sea anemones). This apparently annual cycle paralleled the development of oocytes in females (Fig. 2). Ripe females were found in September and Oc­ tober 1977; spawning occurred between October and November, and no oocytes were observed during the winter. However, collections made on 15 March, 20 April and 24 May indicated that the females were again maturing (Fig. 2). One hermaphrodite was collected on 24 May 1978. This anemone contained vesicles of tailed sperm and small oocytes in the same mesentery. Further, several specimens of Bunodosoma cavernata exhibited ver!ical col­ umnar scars which indicated that they had undergone asexual reproduction by longitudinal fission, as for example in Anthopleura elegantissima (Hand, 1955; Sebens, 1977, 1980). Bunodosoma cavernata ~ N ~ 12 per collect ion 0 5 10 % P : Brooded plonuloe present ( N) -f ~ Spowning 200 P(9) P(8l P(ll) P(ll) P(9) P(ll) E 3 .... 150 ~ (1) No No E 100 0 oocytes oocytes 0 ~ 50 :>-. u 0 0 Nl' 7 0 0 3 6 3 Sept Oct Nov Dec Jon Feb Mar Apr May Jun 1977 1978 F1c. 2. Size-frequency histogram of oocyte dia of Bunodosoma cavcrnata . Legends a~ in Fig. 1. Aiptasia pallida from Sebastian Inlet underwent asexual reproduction by pedal laceration in the field and in laboratory aquariums; it thus formed clones of genetically similar individuals. Ripe females were collected on 19 September 1977 (Fig. 3). These anemones contained oocytes up to 80 Jlm dia. By 27 October 1977 the population had spawned. Oocyte diameters re­ mained small in the 13 December 1977 collection. By 8 February 1978, oocytes were growing larger. As no oocytes were observed in collections made on 27 March 1978, it is possible that the population had spawned again. However, large oocytes (50 JLm and up) were observed in collections l i 182 FLOIUDA SCIENTIST [Vol. 46 E Aiptasia pal/ida ~ 3 0 5 10 N = 12 (1st three collect1onsl .... 24 (lost four collections) ~ "· (1) f = Spawning E 100 0 0 (1) 50 No >- <.J ,C?oocytes 0 0 I 'I N~ 8~. 4 I 3 0 I~7 6 Sept Oct Nov Dec . Jon Feb Mar. Apr May Jun. 1 1977 1978 FIG. 3. Size-frequency histogram of oocyte dia of Aiptasia pallida. Legends as in Fig. l. made on 7 May and 6 June, so it is also possible that the lack of identifiable females in the 27 March sample was simply a collection artifact. Two males were found on 7 May in an adjacent clone. Actinia bermudensis brooded planular larvae throughout the year (Table 1) . Planulae were present in 50% of the anemones collected on 16 September t 1977 and in 60% or more of anemones in all subsequent collections. Of 41 females examined, 31 (76%) contained at least 1 larva. Four of the 5 males were brooding, as were 24 of the 36 anemones with no gonads (67%). As in Actinia bermudensis, Bunodosoma cavernata brooded planular larvae throughout the year. Planulae were present in 60% of the anemones col­ lected on 5 October 1977, and in 82% to 92% of anemones in 4 collections made from 20 January to 24 May 1978. Of 19 females examined, 14 (74 o/o) !I contained at least 1 larva.