This is the third year that Xavier High School is conducting an extensive coral reef monitoring program. In 1997, using the United Nation Environmental Program Coral Reef Monitoring Handbook (UNEP CRMH), a survey was conducted by three members of the class of 1997 on a reef next to the wreck of a Japanese WWII torpedo-bomber airplane, a Nakajima B6N (allied codename "Jill"), located off Parem, an island 4.5 miles southeast of Weno. This wreck artifact was a significant factor influencing the choosing of this site. In 1998, a reef survey was conducted at the Xavier Dock, site of much field work for Xavier marine science students.

This year, again using the UNEP CRMH, twelve members of the class of 1999 were involved in studying three different reefs in the lagoon, from March 5 to May 7, 1999:

1. Off the Japanese Dock, approximately a mile form the Xavier Campus, in the village of Sapuk, Weno.
2. Off the dock near the Catholic church, Parem Island.
3. Two Japanese ship wrecks from the Second World War, the Hoyo Maru, off Fefan Island, and the Suzuki, a Momi-class destroyer, off Toloas Island.

Additionally, this year a market survey was conducted to investigate the amount of marine produce consumed on a daily basis. Our survey was limited to the main commercial island of Weno, where most of the fish caught in, and sometimes outside, the lagoon is sold. Our survey included all the local markets selling any form of marine life, the major restaurants and grocery stores, the Blue Lagoon Resort, Chuuk Star Hotel and the Truk Stop Hotel, the National Fisheries Corporation, and a tuna mothership anchored in the lagoon.

"Fish counts taken indicate the numbers of predator fish and the butterfly fish in the area being surveyed. According to the CMRH(Coral Monitoring Reef Handbook), predator fish to be counted were the Lutjanidae (Snappers), Lethrinidae (Emperors), and Serranidae (Groupers)." (1998 M.S. T.S.P.) At the Japanese Dock site, the most commonly seen predator were lethrinids (Emperors), especially Lethrinus harak, snappers, especially Lutjanus fulvus, and the dwarf grouper, Epinephelus merra. In deeper water of more than 60 feet, L. olivaceus become relatively common, with schools of more than 30 individuals observed on days spent underwater (pers. Comm., Kenneth Yong, SJ). The butterfly fish was also common at the Japanese Dock site, with Chaetodon trifasciatus and C. auriga the two the most widely seen species.

According to the CRMH, the presence of predator fish is an indicator both of fishing pressure and of the presence of prey fish – the higher the number of predators, the higher the number of abundant food supply. "The scarcity of predator fishes mean that fishing pressure at a particular site is high – predator fish species are the most sought after food fishes in Micronesia, next to parrot fish and some species of wrasses."(1998 M.S. T.S.P.) Butterfly fishes, because they are easily recognized, and because they generally inhabit healthy reef areas, tell us much of the well-being of a reef. At the Japanese Dock site, the count of predator fish was low indicating high fish pressure- spear fishing, line-fishing, and dynamite fishing are all activities that are known to be conducted at the Japanese Dock site. The count of butterfly fish was high. This indicates that the Japanese Dock aquatic area sustains a substantial amount of marine life – despite the high fishing activity in the area.

About 10% of the area survey was composed of rubble and blocks made up of broken coral. Damage can be both natural and caused by man. Wave action probably constitutes much of the natural damage – the Japanese dock lies in an area that is exposed to periods of sustained wind (generally between November and April), which causes waves that damage the delicate staghorn coral. Damage from human activity is much more significant -- dynamite fishing, swimmers and fisherfolk standing on live corals thus killing or breaking them, vandalism, e.g., scratching of names on boulder corals, boat anchoring, collecting for building materiel, and dredging, whether for aggregate in the making of concrete, or for channel widening. All these activities were observed at or near the Japanese Dock, and it is obvious that most of the impact on the reef comes from the ever expanding range and frequency of human use of the reef.

Live hard coral comprised about 30% of the area survey. Live hard coral cover was uneven – areas of mostly healthy live coral would alternate with more or less round patches of rubble, an indication of the frequent dynamite fishing that occurred here in the recent past (according to the villagers who live nearby, dynamite fishing at the Japanese dock is no longer common). Staghorn, Acropora sp., and massive, Porites sp., corals were the dominant forms. Generally, at our survey sites, staghorn coral becomes more common the deeper the water, with large stands of branching coral, mostly Porites rus and P. nigrescens, also present. In the shallow reef flat area exposed to regular wave action, the more robust massive coral and corymbose branching coral, especially Porites rus, were the most common. In deeper waters more than 10 feet deep, thickets of Acropora formosae dominated. 9; (See the discussion under Parem for a comparison of boulder coral sizes).

Of soft corals and sponges recorded the most dominant type was the massive soft corals, Sinularia sp. and Sarcophyton sp.. Soft corals can generate under conditions that hard corals cannot, e.g. in areas of high turbidity. This was borne out by the fact that soft corals were more common in the shallow windward side of the dock, where the water was usually turbid due to wave action.

The most common marine algae at the Japanese Dock site are various species of Halimeda. Enhalus acoroides formed a large seagrass meadow in the shallow shoreside of the reef – few marine plants were actually recorded in the sruvey plots. Other common algae present are brown algae species like Dictyota sp., Sargassum sp., Padina sp., and Turbinaria ornata. At the dock itself, Caulerpa racemosa blankets the windward side. Thalasssia hemprichii, Cymodocea serrulata and Syringodium isoetifolium were the other grass species present near and around the dock.

This year there was an outbreak of filamentous blue-green algae, covering a large area between the depths of 2-30 ft. This outbreak was also observed elsewhere in the lagoon, and at the other Pacific islands of Guam, Palau, and Yap, making it a widespread phenomena. Higher levels of nutrients, particularly nitrates and phosphates, usually trigger algal blooms. Agricultural run-off usually accounts for the elevated presence of nitrates and phosphates in the water (these nutrients being the main constituents of fertilizer), but this is probably not the reason for the outbreak in the lagoon, since there is not much intensive agriculture around the Japanese dock. One probable cause is the heavy run-off of nutrients naturally occurring in the soil – last year’s El Niño induced drought was followed by much heavier than usual rains this year. The resultant increase in nutrients could have caused the increase in algae levels. One interesting result of this outbreak is the higher levels of dissolved oxygen measured at the Japanese dock compared to last year – a maximum of 11.9 mg/L in 1999, and 8.5 in 1998 (in other sites surveyed by the Xavier High School Water Quality Team, the same increase in dissolved oxygen levels were also observed, especially where algal blooms were large). Although the presence of this algae is unsightly and seems to be detrimental to coral (the algae clings to all available strata, including live coral), the long term effects will only be known with subsequent monitoring.

Anything man made, with the exception of World War II artifacts and structures like docks and fish traps, was noted as pollution. Visible pollution noted include soda cans, disposable diapers, shoes, fishing nets, bottles, fish lines, motor vehicles and attendant parts, clothing, plastic and paper bags. Some of these pollutants have become anchoring ground for a wide variety of algae and other sessile marine life. Others are unsightly, e.g. soda cans and bottles, and some could cause damage to the reef, e.g. oil and gas release from motor vehicle parts.

"Easily distinguished types of marine life-forms were chosen to indicate the health of the coral reef. Since both mushroom corals and starfish are particularly popular as tourist souvenirs, their counts can give us a clearer picture of tourism activity at an area."(1998 M.S. T.S.P.) For instance, the number of mushroom corals found at the Japanese Dock site was abundant, indicating that there was hardly any tourist activity at the site. Other counts, such as those of the top shells (Trochus sp.), giant clams (Tridacna sp.), sea cucumbers ( Holothuridae), and other sea-shells , show us the harvesting pressure on these marine life, since they are all highly popular delicacies among Micronesians. Throughout the survey area, trochus, giant clam and sea cucumber counts were low. The villagers obviously collect these and other marine-life for food, as evinced by the numbers of empty and broken shells of Trochus sp., spider conches (Lambis sp.), cowries (Cypraea sp.), and the discarded innards of sea cucumbers on the dock. Below thirty feet, on the sand, sea cucumbers, especially Holothuria sp., became abundant, with an average density of 8 per square yard, indicating that most of the collecting of seafood is restricted to the shallows, where the marine life is easily accessible. Holothuria edulis, H. atra, H. (Microthele) axiologa, H. hilla, Stichopus chloronatus, S. variegatus, Bohadschia argus, B. graeffei, B. marmorata, Thelenota annax and Synapta maculata were among the sea-cucumber species noted from the study area.

Fish count

Predator counts per observation swim were higher at Parem than at the Japanese dock., with a maximum of observed on a particular swim. Butterfly fish numbers were also higher, a maximum of observed compared to . The reef off the dock at Parem apparently holds more numbers of the fish under observation, indicating that fishing pressure here is lower than at the Japanese dock. The fish also allowed closer approach by the snorkelers, another indication that they are now as heavily exploited – fish very quickly develop the instinct to flee when frequently pursued for food.

Overall, live hard corals make up nearly 50% of the survey area. All forms of coral listed on the CRMH datasheet were present at Parem, with the same distribution pattern observed at the Japanese dock – massive boulder corals, Porites sp., in shallow water generally less than 10 feet, and staghorn coral, Acropora sp., in deeper water.

Interestingly, the boulder coral at Parem attain an average size significantly larger than at the Japanese dock -- coral heads with a maximum width exceeding 10 feet were common here, whereas the boulder coral at the Japanese dock rarely exceeded 8 feet. Assuming that the reef at Parem and the Japanese dock are of the same age, it should be expected that the boulder corals at both sites would attain the same maximum size, since conditions at both sites are not significantly different. This difference is perhaps due to the collecting of boulder coral for building material at the Japanese dock, since coral boulders are commonly used in all forms of construction in the Pacific, and since the village of Sapuk, where the Japanese dock is collected, was very heavily built up under the Japanese occupation. A telling comparison can be made with the size boulder corals on the Hoyo Maru (see below), which hull is covered by significant boulder coral growth, particularly in shallow water. On the Hoyo Maru, boulder coral average about 8 feet in maximum width. Since we know that the Hoyo sank in February, 1944, we know that the boulder corals on this wreck cannot be older than 56 years (as of 1999). Therefore, the conclusion can be made, from the similarity in sizes between the boulder corals at the Japanese dock and on the Hoyo, that the boulder corals at the Japanese dock are not that much older than on the Hoyo, pointing to major exploitation of these corals at the Japanese dock site during the 1930s and 1940s, unless there is a major difference in growth rates. Again, only long term observation of these corals will tell us if the growth rates on these two sites are different, and if so, how different and perhaps the reasons why.

The outbreak of filamentous blue-green algae observed at the Japanese dock was also seen here.

From the point of view of visible pollution, the Parem reef is much cleaner than the Japanese dock. The most common pollutant observed were bottles and soda cans.

Significantly, giant clams of the species Tridacna squamosa, T. crocea and T. maxima, were observed both inside and outside the survey circles. Additionally, there was a small giant clam farm, mostly T. maxima, located just off the dock, in 8 feet of water. The fact that there were numbers of giant clams in really shallow water points to the low level of exploitation of this reef, as giant clams are a highly popular delicacy among all Pacific Islanders. In Chuuk, giant clams are found in numbers in shallow water only on the barrier islands, and on islands with low or no populations.

The wrecks of Chuuk Lagoon are magnets for fish – the hulls and superstructures afford a firm anchoring ground for all forms of sessile marine life, and the many nooks and crannies offer protection to small fish. This combination of food and shelter in concentration draw many species of fishes, both prey and predator. The Chuukese know that the fishing at these wrecks is good, and many of them are regularly fished using hand-lines, nets, spears, and dynamite (dynamite fishing ion the wrecks has led to some serious damage to the wrecks, e.g., falling-off of hull-plates on the Sankisan Maru, the destruction of much coral life on the Hoyo Maru, and the loss of the masts on the Fujikawa Maru (pers. comm. various local people)). Still, the fish life is rich, with some wrecks harboring large numbers of large predators, especially snappers, groupers, barracuda, jacks and sharks. On the Hoyo and the Suzuki, fish counts were not high -- observer effort was limited by time constraints.

The wrecks, Hoyu and Suzuki, have more than 50% live corals in the surveyed area. The most dominant live hard corals on both wrecks are the massive corals. (See discussion of live hard coral under Parem for comparisons).

On both of the wrecks there are large number of large zigzag clams, Hyotissa hyotis, and Lopha cristagalli. These is perhaps dues to the fact the these species are quick colonizers able to better exploit the conditions at the wrecks – periods of low visibility and high sediment due run-off from the islands, since these wrecks are near shore, are detrimental to the growth of giant clams, which require clear water for maximum sunlight penetration, a requirement for the zooxanthellae that live in symbiosis with these clams, whereas the filter-feeding zigzags benefit from the increased nutrient load during periods of high turbidity.

This was the first year that we conducted a market survey to get a rough idea of the daily sale of marine life as an indication of the economic exploitation of the reefs. A major part of the fish sold at the local markets are reef-dwelling species, as indicated by the species listed under the results above, with the exception being the tunas, commonly Thynnus albacares, Euthynnus affinis and Katsowonus pelamis, rarely Thynnus obesus. By all accounts, fish catches are lower nowadays than they used to be 10 years ago, although there are still large numbers of fish readily available at the markets. From pure observation of the reefs, the fish life still seems bountiful, with large schools of parrotfish, snappers, surgeonfish and other species readily observable, even on heavily exploited reefs like the one at the Japanese dock. At the barrier islands, large numbers of large (over 5 pounds) parrotfish are still easily caught. We really have no idea if the reefs are being overfished, as this is the first year we have any data. Long term monitoring of the markets and the reefs will tell of fishing effort and results. Still, it is safe to say that fishing pressure can only increase, as the population grows ever larger with an attendant increase in food needs.

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