Studies on Spawning in Clownfish Amphiprion sebae with VariousFeed Combinations under Recirculating Aquarium Conditions
Olivia J. Fernando,
Amphiprion sebae kept in the recirculating Marine Research Aquarium spawned a maximum of 0.8 times per month throughout the year. This is the first spawning record from a recirculating aquarium environment. Generally the spawning of A. sebae has been described from fresh seawater by various authors. The present study mainly observes the maintenance of brooders, their pairing and spawning in recirculating aquarium environment. Among the 54 adult fishes collected from the natural environment, three pairs are formed in the aquaria. The parental care of egg guarding male was observed. Three pairs are fed with different feed i.e., prawn meat, fish meat and a combination of prawn, fish and clam meats. The spawning frequency was observed to be moderately high (0.8/month) when fed with the mixed feed, whereas a frequency of 0.5 and 0.6 per months was observed when fed with prawn, fish meats respectively. The maximum clutch size (911) was observed also in mixed feeds and it was minimum (395) when the pairs were fed with fish meat alone. The increase in the frequency of spawning was during summer months compared to other months.
Nowadays, the marine ornamental fish industry is developed day by day. Conroy (1975) valued the world retail trade in fish keeping at only US $ 250 million in 1970s. A rapid increase in the harvest of marine species for home aquaria occurred in the 1980s (Andrews, 1990) and exports have continued to increase in the 1990s (Vallejo, 1990). According to Bassleer (1994) world wholesale trade in ornamental fish is worth about US$ 900 million. But after two decades, Devenport (1996) estimated the total world retail trade including live fish, associated equipments and accessories at US$ 7,000 million and the retail trade in live products at US$ 3,000 million. These dramatic developments of this industry can be directly affecting the wild population of the marine ornamental fishes. The overexploitation resulting in depletion of certain species of ornamental fishes (Wood, 1985) has presented aquaculture with an opportunity to enter a new market and provide a consistent supply of marine aquarium fish to an increasing market through the development of captive breeding programmes.
The family Pomacentridae, particularly the clownfish species of the genus Amphiprion,
represents the most important group of captive-bred marine species. They are
also considered a good reference fish for scientific research, especially for
nutritional studies and the determination of spawning the eggs and larval quality
(Delbare et al., 1995). The spawning of clown fishes in wild appears
to be varying with latitude. Clownfish species occurring in tropical waters
spawn throughout the year (Allen, 1972; Ross, 1978), whereas in more temperate
regions spawning occurs only during the warmer summer months (Bell, 1976; Moyer,
1980; Ochi, 1985; Richardson et al., 1997). However, in temperate clownfish
species, the correlation between spawning periodicity and moon phase becomes
much weaker (Richardson et al., 1997). Generally, the reproductive cycle
of fishes in the aquarium environment is very often absent or weak. This is
mainly due to the low water quality conditions in such environments. As a result,
fish become entrained by the simulated temperatures and lighting regimes imposed
by the aquarist and reproductive activity changes accordingly (Kohler et
al., 1994). Clownfish, in aquaria, appear to breed throughout the year (Alava
and Gomes, 1989; Hoff, 1996), with an increase in the number of spawning during
the spring and summer months (Hoff, 1996). In the present study, an advanced
filtration system such as protein skimmer and ozoniser was not used and the
recycling is mainly by the basic filters.
Materials and Methods
Fifty four numbers of adult (6 to 8 cm total length) A. sebae were collected from Gulf of Mannar, Southeast coast of India and transported to the Marine Research Aquarium. They are divided into three groups in three different aquarium tanks. Pairs of clownfish were each placed in 2000 L concrete (floor with tiles) glass mount aquaria and connected to a 40,000 L partially recirculating system. During the course of the study pairs were fed twice a day. After the pairing in aquarium tanks they were observed twice daily, in the morning and late afternoon, for evidence of spawning. There is no 100% exchange of water with natural seawater. However, the evaporation and seepage are compensated with natural seawater. The natural seawater is drawn directly from the mouth of a nearby estuary and transported in plastic tanks to the Marine Research Aquarium at a distance of 25 km. The aquarium was incorporated with filters and daily water exchange rate is 10% in each experimental aquaria. The entire recirculating system is showed in Fig. 1. Aquarium floors are covered with crushed sea shells and spawning decor was provided in the form of earthen pots and 50 mm PVC pipes.
Throughout the study period water quality parameters ranged within accepted
limits and when required it was balanced immediately by 50% of water exchange.
The overall pH ranged from 8.01 to 8.35 and salinity from 33 to 36. The
Ammonia was measured at 0.01 to 0.09 mg L-1 and NO3 levels
were below 4 mg L-1. Water temperature was maintained by means of
centralized air-conditioner and the data was collected from the aquarium in
broodstock system ranged from 26 to 32°C. There is no natural light entering
|| Technical view of the recirculating system of the present
Supplementary artificial lighting was provided by cool white fluorescent tubes
situated 30 cm above each tank and set on a 10 h light: 12 h dark cycle. Under
these experimental conditions, the clown fish behaviors of pairing, spawning
and clutch size characters are observed.
Results and Discussion
In the present study spawning frequency in relation to various feeds was observed. The overall spawning records are showed in Table 1. The duration was calculated, when the first spawning occurred in the tanks. The total numbers of eggs are also counted approximately and given in Table 2.
Research on spawning and clutch characteristics of marine ornamental fishes is still relatively in its earlier stages. Ignatius et al. (2001) have provided data on the spawning behavior of A. sebae from Indian waters. It is not extensive whereas during the present study a 15 months study was undertaken. Data on spawning was collected from March 2005 to June 2006. During the period of pair formation twenty three female fishes died. Among these, 13 fishes died due to the fighting behavior of brooder fishes within the tank. This behavior is common in other Amphiprion species that is observed by Hoff (1996). He noted that when pairing formed in a tank, the pair fishes tend to stay together and chase others from specific areas and eventually attempt to destroy others. In the present study the affected fish could be easily identified by its fin damage and when it always stands in the corner of the tank. This chasing behavior sometime occurred vigorously resulting in mortality. The other ten fishes may have died due to weak immune system with regard the change in water quality and environment. After the pair formation in three tanks the remaining twenty five fishes are removed from that tank. However, not all the three pairs provided data for the duration of the study as pairs began to breed at different times and an individual from each of two pairs died after their 4th and 5th spawning. This mortality may be due to their feed. The dead pairs are fed with the same type of feed i.e., prawn meat and fish meat respectively throughout the study period. But it was noticed that in the third pair fed with a mixed feed spawned more frequently (Table 3).
Year-round spawning for captive Amphiprionae at Instant Ocean Hatcheries (IOH)
in Florida is reported (Hoff, 1996), with A. akallopisos spawning an
average of 2.4 times per month (Table 3). Year-round spawning
is also recorded for wild populations of tropically occurring A. chrysopterus,
A. perideraion (Allen, 1972) and A. melanopus (Allen, 1972; Ross,
1978). In contrast, low water temperatures and more unstable environmental conditions
of temperate regions resulted in spawning occurring only during the summer months
(Richardson et al., 1997). In the present study also more spawning occurred
during summer compared to other months.
|| The spawning records of A. sebae in marine research
|ASF- Amphiprion sebae fed with fish meat only, ASP-A.
sebae fed with prawn meat only, ASM-Amphiprion sebae fed with
mixed feed i.e., prawn, fish, clam meats
|| The maximum, minimum and mean (SD) clutch sizes of A.
sebae in the present study
|( )*- Number of spawning
|| Comparison of spawning records of clownfish pairs at Instant
Ocean Hatchery (Hoff, 1996) and the present study
||The spawning and parental care of clown fish A. sebae in
Marine Research aquarium
Wild populations of A. clarkii from Miyake-jima and Shiko-ku Island
spawned 7.0 and 5.5 times per year, respectively (Bell, 1976; Ochi, 1985, 1989),
while A. clarkii in captivity spawned 34.6 times per year (Hoff, 1996).
There is no particular spawning data in natural and captive environment of A.
sebae (Fig. 2).
In the present study the clutch size and annual fecundity is less compared
to the natural environment. The environmental factors are important in modifying
the reproductive behavior and biology of the anemonefish (Moyer, 1980; Richardson
et al., 1997). Hoff (1996) reported increased spawning frequency during
spring and summer months in captive Amphiprionae at Instant Ocean Hatchery (IOH).
Broodstock at IOH and Oceanic Research Institute (ORI) hatchery, were exposed
to ambient light in addition to artificial light and depended to a certain degree
on solar heat to maintain water temperatures. Consequently, photoperiod and
water temperatures fluctuated with the seasons. Increased spawning frequency
in Amphiprionae has been attributed to the shorter time taken for incubation
of embryos at higher water temperatures (Bell, 1976; Hoff, 1996; Richardson
et al., 1997). It has also been suggested that larval and juvenile fitness
may be enhanced at warm water temperatures due to higher growth rates and a
reduction in temperature related stress (Moyer, 1980). During the present study
it could not be discerned whether water temperature or photoperiods were factors
influencing spawning frequency. Fluctuations in water temperature in the aquarium
had no correlation with spawning frequency of clownfish. Perhaps temperatures
in the present aquarium did not drop to the level where embryo incubation time
is increased and consequently spawning frequency reduced. It is, therefore,
postulated that the increase in photoperiod or light intensity associated with
summer may play more of a role in increasing the number of spawning at this
time. Moyer (1980) who observed the influence of photoperiod on spawning of
wild clownfish A. clarkii at Miyake-jima suggested that diminishing light
and not water temperature restricted their breeding season. Hoff (1996) believes
light intensity and photoperiod were not major factors influencing spawning
frequency at IOH. Data showed that clownfish at IOH consistently spawned more
frequently during December than the other months, even though December experienced
the shortest day in terms of photoperiod and lowest light intensity. In the
present study clownfish are exposed to ambient light, but it is likely that
the surrounding lights may prevail any effect on their reproductive cue. But
most of the spawning was recorded during the full or new moon times. This could
account for the different spawning frequencies at different moon phases.
Gardon et al. (1998), Johnston et al. (2003) and Sales and Janssens (2003) are pioneer researchers regarding the nutrition studies i.e., the effect on growth and survival of larvae of clownfishes and other ornamental fishes. Studies on influence of nutrition on ornamental fish are hampered by the lack of suitable measurement other than growth (Johnston et al., 2003) whereas in the present study, the effect of feed on the spawning frequency was observed. It was observed that the adult A. sebae could be weaned onto a mixed feed with a significant spawning record compared to other weaning experiments. According to Pannevis (1993) it was also proved that the ornamental fish can exhibit a very consistent preference for one diet over another when two or three diets are offered simultaneously.
Although this study was a small-scale pilot study, it is hoped that it would through light on the interactions between environmental factors and spawning frequency and periodicity in A. sebae maintained under recirculating aquarium conditions. Further trials should be conducted using larger numbers of broodstock and their larval rearing commercial basis and focus specifically on synthetic seawater.
We thank the authorities of Annamalai University for allowing use of Marine Research Aquarium in the present study.
1: Alava, V.R. and L.A.O. Gomes, 1989. Breeding marine aquarium animals: The anemonefish. Naga. ICLARM Quart., 12: 12-13.
2: Allen, G.R., 1972. Anemonefishes. T.F.H. Publications, Neptune, pp: 288
3: Andrews, C., 1990. The ornamental fish trade and fish conservation. J. Fish. Biol., 37: 53-59.
Direct Link |
4: Bassleer, G., 1994. The international trade in aquarium/ornamental fish. Infofish Intl., 5: 15-18.
5: Bell, L.J., 1976. Notes on the nesting success and fecundity of anemonefish Amphiprion clarkii at Miyake-Jima, Japan. Jap. J. Ichthyol., 22: 207-211.
6: Conroy, D.A., 1975. An evaluation of the present state of world trade in ornamental fish. FAO Fisheries Technical Paper, No. 146.
7: Davenport, K.E., 1996. Characteristics of the current international trade in ornamental fish, with special reference to the European Union. OIE Revue Scientifique et Technique, 15: 436-443.
8: Gardon, A.K., H. Kaiser, P.J. Britz and T. Hecht, 1998. Effect of feed type and age at weaning on growth and survival of clownfish Amphiprion percula (Pomacentridae). Aquarium Sci. Conserv., 2: 215-226.
9: Hoff, F.H., 1996. Conditioning, Spawning and Rearing of Fish with Emphasis on Marine Clown- Fish. Florida Aqua Farms Inc., Dade, USA., pp: 212
10: Ignatius, B., R. Gaurau, I. Jagadis, D. Kandasami and A.C.C. Victor, 2001. Spawning and larval rearing technique for tropical clown fish Amphiprion sebae under captive condition. J. Aqua. Trop., 16: 241-249.
11: Johnston,G., H. Kaiser, T. Heechi and L. Ollermann, 2003. Effect of ration size and feeding frequency on growth, size distribution and survival of juvenile clownfish, Amphiprion percula. J. Applied Icthol., 19: 40-43.
12: Kohler, C.C., R.J. Sheehan, C. Habiche, J.A. Malison and T.B. Kayes, 1994. Habituation to captivity and controlled spawning of white bass. Trans. Am. Fish. Soc., 123: 964-974.
13: Moyer, J.T., 1980. Influence of temperate waters on the behavior of the tropical anemonefish Amphiprion clarkii at Miyake-Jima, Japan. Jap. J. Ichthyol., 23: 23-32.
14: Ochi, H., 1985. Temporal patterns of breeding and larval settlement in a temperate population of the tropical anemonefish, Amphiprion clarkii. Jap. J. Ichthyol., 32: 248-257.
CrossRef | Direct Link |
15: Ochi, H., 1989. Mating behavior and sex change of the anemonefish, Amphiprion clarkii, in the temperate waters of Japan. Environ. Biol. Fish., 26: 257-275.
CrossRef | Direct Link |
16: Pannevis, M.C., 1993. Nutrition of Ornamental Fish. In: The Waltham Book of Companion Animal Nutrition. Burger, I.H. (Ed.). Pergamon Press, Oxford, pp: 85-96
17: Richardson, D.L., P.L. Harrison and V.J. Harriott, 1997. Timing of spawning and fecundity of a tropical and subtropical anemonefish (Pomacentridae: Amphiprion) on a high latitude reef on the east coast of Australia. Mar. Ecol. Prog. Ser., 156: 175-181.
18: Ross, R.M., 1978. Reproductive behavior of anemonefish Amphiprion melanopus on Guam. Copeia, pp: 103-107.
19: Sales, J. and J.P.G. Janssesns, 2003. Nutrient requirements of ornamental fish. Aquat. Living Resour., 16: 533-540.
CrossRef | Direct Link |
20: Vallejo, B.V., 1997. Survey and review of the Philippine marine aquarium fish industry. Sea Wind, 10: 25-26.
21: Wood, E.M., 1985. Exploitation of coral reef fishes for the aquarium trade. Report to the Marine Conserv. Soc., pp: 121.
22: Delbare, D., P. Lavens and P. Soregloos, 1995. Clownfish as a Reference Model for Nutritional Experiments and Determination of Egg/larval Quality. European Aquaculture Society, Trondheim, Norway, pp: 22-25