Grutter, A.S., Deveny, M.R., Whittington, I.D. and R.J.G. Lester. 2002. The effect of the cleaner fish Labroides dimidiatus on the capsalid monogean Benedenia lolo parasite of the labrid fish Hemigymnus melapterus. Journal of Fish Biology 61:1098-1108.

Cleaner wrasses have long been recognized as predators on various parasitic crustaceans commonly found on fish. This study shows that the common south Pacific cleaner wrasse, Labroides dimidiatus, can also feed on and control, the monogean (trematode) parasite Benedenia lolo, on the wrasse Hemigymnus melapterus. Monogeans often become problematic in aquaculture and aquaria situations once they are introduced due to poor quarantine procedures. They can often show explosive growth in numbers and can be very difficult to eradicate once introduced. Chemicals and freshwater baths are often used to control their numbers and prevent their introduction into systems but these can be expensive and/or time consuming.

This is a photo, taken by Julian Sprung, of a yellow puffer ( Anthron sp.) with a cleaner wrasse ( Labroides dimidiatus ) entering its gill for cleaning purposes. For those of you who recall this photo was used as the cover photo for the original Aquarium Frontiers, Fall 1994.

This study examined how effective the cleaner wrasse was in removing monogeans and what effect they would have on their abundance and size-frequency distribution under the controlled conditions of an aquarium. In the test aquaria it was found that small fish (<11.5 cm) had 100x the number of monogeans of wild small fish while large fish (>11.5 cm) had 15x the number. Small fish had higher densities of monogeans than larger fish and had greater numbers of small monogeans (<1 mm) indicating that small fish appeared to be more susceptible to infection by the motile infectious stage of monogeans. However, large fish had more large monogeans (> 3mm). Fish can exhibit immunity to parasites and this immunity can be acquired. It was thought that the increased susceptibility to monogeans in smaller fish might be linked to a lower resistance to disease as has been shown in other fish parasites and fish species and that as they grow larger they acquire an increased immunity to
infection.

In the presence of cleaner wrasses, small fish had significantly fewer monogeans than fish not exposed to cleaner wrasses. The abundance on large fish was not affected. Within the two fish size-classes, cleaner wrasses did affect the size-frequency distribution of monogeans. Fish had fewer large monogeans and more small monogeans than those fish not exposed to cleaner wrasses. This effect was more pronounced on large fish than on small fish.

This study indicates that cleaner wrasses can help to control benedeniine monogean populations in closed systems; however, there is a difference in how they can affect the population depending on the size of the fish involved. By selectively removing large monogeans, cleaner wrasses can help to slow the spread of infection and perhaps, over time, even eliminate them from systems. However, for hobbyists that have relatively small systems with low fish densities, and who should be acquiring fish that have already been adequately quarantined, the role of cleaner wrasses in such systems in questionable. Wholesalers and other importers on the other hand, may benefit from keeping a small population of cleaner wrasses in large holding systems where large fish are regularly held. This does not, however, preclude the need for pretreating fish upon arrival from areas known to have high incidences of monogean infections on fish e.g. Marshall Islands, Christmas Island with freshwater baths or
medication.

For public aquariums or other facilities that house large populations of both large and small fish, cleaner wrasses can be useful tools to help control the spread of benedeniine monogeans or while chemical means are used to totally eradicate them.

Unless you are 110% confident that the fish you purchase are free of disease, then hobbyists should always quarantine any new arrivals in a separate system for at least three weeks to ensure they are not carrying any disease and are eating and behaving normally.

Corals and Stress

1. Nordemar,I., Nystrom, M. and R. Dizon. 2003. Effects of elevated seawater temperature and nitrate enrichment on the branching coral Porites cylindrica in the absence of particulate food. Marine Biology (in press). (Abstract: http://link.springer.de/link/service/journals/00227/contents/02/00989/)
2. Bassim, K.M. and P.W. Sammarco. 2003. Effects of temperature and ammonium on larval development and survivorship in a scleractinian coral ( Diploria strigosa )._ Marine Biology (2003) 142: 241-252. (Abstract: http://link.springer.de/link/service/journals/00227/contents/02/00953/).

These two studies both underline the stresses placed on corals that are exposed to not only elevated temperatures but also elevated nitrate and ammonium levels. The levels of ammonium and nitrate used in these studies are lower than found in most hobbyist systems and underscore that our systems are not always close approximations to nature. This is something that I have long argued when others have advocated raising temperatures or making other changes to our systems while ignoring other factors that can act synergistically to create problems.

Anemones

1. Baeza, J.A. and W. Stotz. 2003. Host-use and selection of differently colored sea anemones by the symbiotic crab Allopetrolisthes spinifrons. Journal of Experimental Marine Biology and Ecology 284(1-2): 25-40.

Aquaculture

1. McMillian, J.D., Wheaton, F.W., Hechheimer, J.N. and J. Scares. 2003. Pumping effect on particle sizes in a recirculating aquaculture system. Aquacultural Engineering 27(1): 53-60.
2. Rombaut, G., Grommen, R., Zizhong, Q., Vanhoof, V., Suantika, G., Dhert, P., Sorgeloos, P. and W. Verstraate. 2003. Improved performance of an intensive rotifer culture system by using a nitrifying inoculum (ABIL). Aquaculture Research 34(2): 149-164.

Cephalopods

1. Nabhitabhata, J. 2003. Double eggs of pharaoh cuttlefish, Sepia pharaonis Ehrenberg, 1831. Veliger 46(1): 97-98.
2. Norman, M.D., Paul, D., Finn, J. and T. Tregenza. 2002. First encounter with a live male blanket octopus: the world’s most sexually size-dimorphic large animal. New Zealand Journal of Marine and Freshwater Research 36(4): 733-736.

Corals

1. Anthony, K.R.N. and O. Hoegh-Guldberg. 2003. Kinetics of photoacclimation in corals. Oecologia 134(1):23-31.
2. Duh, C.Y., Chien, S.C., Song, P.Y., Wang, S.K., ElGamal, A.A.H. and C.F. Dai. 2002. New cadinene sesquiterpenoids from the Formosan soft coral Xenia puerto-galerae. Journal of Natural Products 65 (12): 1853-1856.
3. Duh, C.Y., ElGamal, A.A.H., Chiang, C.Y., Chu, C.U., Wang, S.K and C.F. Dai. 2002. Cytotoxic Xenia diterpenoids from the Formosan soft coral Xenia umbellata. Journal of Natural Products 65 (12): 1882-1885.
4. Savage, A.M., Goodson, M.S., Visram, S., Trapido-Rosenthal, H., Wredenmann, J. and A.E. Douglas. 2002. Molecular diversity of the symbiotic algae at the latitudinal margins of their distribution: dinoflagellates of the genus Symbiodinium in corals and sea anemones. Marine Ecology Progressive Series 244:17-26.
5. Saxby, T., Dennison, W.C. and O. Hoegh-Guldberg. 2003. Photosynthetic responses of the coral Montipora digitata to cold temperature stress. Marine Ecology Progressive Series 248: 85-97.
6. Sheu, J.H., Ahmed, A.F., Shiue, R.T., Dai, C.F. and Y.H. Kuo. 2002. Scabrolides A-D, four new norditerpenoids isolated from the soft coral Sinularia scabra. Journal of Natural Products 65 (12): 1904-1908.
7. Vermeij, M.J.A., Sampayo, E., Bröker, K. and R.P.M. Bak. 2003. Variation in planulae release of closely related coral species. Marine Ecology Progressive Series 247: 75-84.
8. Villinski, J.T. 2003. Depth-independent reproductive characteristics for the Caribbean reef-building coral_ Montastraea faveolata_. Marine Biology (In press). (Abstract: http://link.springer.de/link/service/journals/00227/contents/02/00997/).
9. Yacobovitch, T., Weis, V.M. and Y. Benayah. 2003. Development and survivorship of zooxanthellate and azooxanthellate primary polyps of the soft coral_ Heteroxenia fuscescens_: laboratory and field comparisons. Marine Biology (In press). (Abstract: http://link.springer.de/link/service/journals/00227/contents/03/01035/).

Ecology

1. Knott, M. 2003. The net is closing on coral reef bombers. New Scientist 177(2377): 6-7.
2. Nagelkerken I. and G. van der Velde. 2002. Do non-estuarine mangroves harbour higher densities of juvenile fish than adjacent shallow-water and coral reef habitats in Curaçao (Netherlands Antilles)? Marine Ecology Progressive Series 245: 191-204.
3. Nagelkerken, I., Roberts, C.M., vanderVelde, O., Dorenbosch, M., vanRiel, M.C., delaMorinere, E.C. and P.H. Nienhuis. 2002. How important are mangroves and seagrass beds for coral reef fish? The nursery hypothesis tested on an island scale. Marine Ecology Progressive Series 244: 299-306.
4. Sale, P. and R. Bshary. 2003. Coral reef fishes: Diversity and dynamics in a complex ecosystem. Nature 412(6921): 317-319.

Fish

1. Asoh, K.2003. Gonadal development and infrequent sex change in a population of the humbug damselfish,_ Dascyllus aruanus_, in continuous coral-cover habitat. Marine Biology (In press). (Abstract: http://link.springer.de/link/service/journals/00227/contents/03/01051/).
2. Finley RJ, Forrester GE. 2003. Impact of ectoparasites on the demography of a small reef fish. Marine Ecology Progressive Series 248:305-309.
3. Greenfield, D.W. and K. Matsuura. 2002. Scorpaenades quadrispinosus: a new indo-Pacific scorpionfish (Teleostei: Scorpaenidae). Copeia 4: 973-978.
4. Mitchel, J.S. 2003. Social correlates of reproductive success in fake clown anemonefish: subordinate group members do not pay-to-stay. Environmental Ecology Research 5(1):89-104.

Seagrass

1. Agawin, N.S.R. and G.M. Duarte. 2002. Evidence of direct particle trapping by a tropical seagrass meadow. Estuaries 25(6A): 1205-1209.
2. Durako, M.J., Kunzelman, J.I., Kenworthy, W.J. and K. K. Hammerstrom. 2003. Depth-related variability in the photobiology of two populations of Halophila johnsonii and Halophila decipiens. Marine Biology (In press). (Abstract: http://link.springer.de/link/service/journals/00227/contents/03/01038/).
3. Thomas, F.I.M. and C.D. Cornelisen. 2003. Ammonium uptake by seagrass communities: effects of oscillatory versus unidirectional flow. Marine Ecology Progressive Series 247: 51–57.

Sponges

1. The second 2003 issue of Journal of Biotechnology (vol. 100 issue 2) is a special installment entitled, Biotechnological Aspects of Marine Sponges. It contains several papers dealing with the culture of marine sponges and would be a useful issue for those interested in culturing and growing sponges in aquaria.
2. Guzmán, H.M., Guevara, C.A. and I.C. Hernández. 2003. Reproductive cycle of two commercial species of sea cucumber (Echinodermata: Holothuroidea) from Caribbean Panama. Marine Biology (2003) 142: 271-279
3. Ramofafia, C., Byrne, M. and C. S. Battaglene. 2003. Reproduction of the commercial sea cucumber Holothuria scabra (Echinodermata: Holothuroidea) in the Solomon Islands. Marine Biology (2003) 142: 281-288.
4. Steindler, L., Beu, S. and M. Ilan. 2002. Photosymbiosis in intertidal and subtidal tropical sponges. Symbiosis 33(3):263-?.