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Although jellyfish are important predators of fish larvae, many fish species also feed on jellyfish. Therefore, the predator–prey role of jellyfish and fish may switch during the course of their life histories. Here, we investigated such interactions by examining (1) the avoidance behaviour of threadsail filefish Stephanolepis cirrhifer to moon jellyfish Aurelia sp. and (2) the feeding behaviour of filefish on moon jellyfish medusae and polyps. The efficiency of filefish as jellyfish predators was examined by comparing their behaviour with that of black scraper Thamnaconus modestus and red sea bream Pagrus major. Filefish and black scraper were able to avoid medusae and obtain tolerance against nematocysts at a smaller body size compared to red sea bream. Filefish initiated feeding on medusae when they became juveniles of 21.8 mm SL. Feeding trials of yearling filefish on polyps at different temperatures (range 10–30°C) indicated that the highest feeding rate was 3.1 individuals s−1 at 26.8°C. We suggest that the feeding pressure of filefish on jellyfish polyps may have an impact on medusa biomass.

We examined the diel activity pattern of the sea cucumber Apostichopus japonicus with or without the presence of food and predators. We also tested whether they have the capability for time–place learning. In the feeding experiment, juvenile and adult sea cucumbers were fed at either 00:00 or 12:00, at a fixed feeding place for 12 days, and the presence of animals in the feeding area was recorded. In the predator experiment, juvenile sea cucumbers were kept in a tank with or without a filefish, and the emergence of juvenile sea cucumbers outside the oyster shell area was recorded. Juvenile sea cucumbers did not show a diel activity rhythm, whereas adults were nocturnal, but this was altered by feeding at 12:00. Neither juveniles nor adults appeared in the feeding area before feeding time, suggesting an inability for time–place learning. Juvenile sea cucumbers hid under the oyster shells during the daytime and were active at night in the presence of a filefish, but without a filefish, they also showed high activity in the daytime. We suggest that sea cucumbers change their activity depending on the presence of food and predators, but without the influence of time–place learning.

Electron spin resonance (ESR) analysis was conducted for eight different kinds of dried seafood products to investigate their gamma-irradiation status. The specimens consisted of 0∼10 kGy-irradiated bones, which included five dried fishes (plaice, hairtail, saury, herring, and dried filefish) and three dried mollusks (beca squid, dried squid, and mitra squid) without flesh or marrow. ESR analysis showed that irradiated specimens exhibited typical asymmetric signals as compared to non-irradiated specimens. ESR signal intensities of all dried fishery samples significantly in- creased depending on irradiation dose, whereas hydroxyapetite radicals clearly appeared in irradiated plaice, saury, and hairtail. In comparing hydroxyapatite (HA) ratio, irradiated hairtail showed a greater hydroxyapatite-radical gen- eration rate than plaice and saury, and the HA ratio significantly increased with elevated irradiation dose. However, all irradiated plaice and hairtail samples, including 5 and 10 kGy-irradiated saury, showed radiation-derived radicals, whereas filefish and mollusks did not. From the results, ESR spectroscopy was found to have potential to be applied for identifying irradiated plaice, hairtail, and saury, which all contained bones.

Past studies suggested that a basin-wide regime shift occurred in 1988–1989, impacting marine ecosystem and fish assemblages in the western North Pacific. However, the detailed mechanisms involved in this phenomenon are still yet unclear. In the Ulleung basin of the East Sea, filefish, anchovy and sardine dominated the commercial fish catches in 1986–1992, but thereafter common squid comprised > 60% of the total catch in 1993–2010. To illuminate the mechanisms causing this dramatic shift in dominant fisheries species, I related changes in depth-specific oceanographic conditions from 0 to 500 m to inter-annual changes in the fish assemblage structure from 1986 to 2010. In the upper layer of 50–100 m depths, water temperature suddenly increased in 1987–1989, and consequently warm-water epi-pelagic species (anchovy, chub mackerel, and common squid) became dominant, while sardine, relatively cold-water epi-pelagic species, nearly disappeared. An annual index of the volume transport by the Korea Strait Bottom Cold Water, originating from the deep water of the Ulleung Basin, displayed a sudden intensification in 1992–1993, accompanied by decreased water temperature and increased water density in the deep water and replacement of dominant bentho-pelagic species from filefish, warm-water species, to herring and cod, cold-water species. The results suggest that climate-driven oceanic changes and the subsequent ecological impacts can occur asynchronously, often with time lags of several years, between the upper and the deep layer, and between epi-pelagic and deepwater fish assemblages.

Using field and laboratory experiments, this study examined the mechanisms that determine the distribution patterns of the filefish Rudarius ercodes, one of the most dominant seagrass habitat fishes in temperate Japan. Few individuals were preyed on in a field tethering experiment, suggesting a relatively low predation risk, even in the open bare sand and mud areas around seagrass habitats. In the laboratory, predator presence or absence did not affect filefish distribution, with filefish mostly staying in the area planted with seagrass, even when predators were absent in the open bare area. Filefish showed a strong preference for the structure provided by seagrass, staying significantly longer in the seagrass area (despite a lack of food) than in the area with food but devoid of seagrass. Faced with the choice of both seagrass and food, and seagrass without food, even satiated filefish, which showed lower foraging activity, remained significantly longer in the seagrass area with food, suggesting an additional preference for seagrass with abundant epiphytic food. Accordingly, habitat preference may be the most important factor determining the distribution patterns of filefish, which may primarily select seagrass habitats via an intrinsic preference for the structure provided by seagrass, with their distribution pattern subsequently being modified by food availability via a preference for seagrass with abundant epiphytic food.

Eun-Joo Park, Han-Na Jang, Deokjo Jo, Gui-Ran Kim, and Joong-Ho Kwon*School of Food Science and Biotechnology, Kyungpook National UniversityAbstract Dried fish products, such as seasoned cuttlefish, anchovy, and filefish, were analyzed to investigate thephysicochemical quality and luminescence properties following gamma-irradiation. The overall color difference slightlyincreased in all irradiated samples, showing significant changes in Hunter’s L, a, and b color values. Cuttlefish and filefishshowed higher values in hydrophilic browning, whereas anchovy showed a higher value in lipophilic browning. The browncolor intensity of filefish showed a dose-dependent increase. The thiobarbituric acid (TBA) value significantly increased inirradiated samples of cuttlefish and anchovy, which have relatively high lipid contents. Irradiated samples, except anchovy,were not suitable for screening using photostimulated luminescence (PSL) because only negative or intermediate valueswere observed. Thermoluminescence (TL) measurements were suitable for all fish samples, i.e., irradiation-specific glowcurves were obtained, signal intensity increased, and the TL ratio fulfilled the criterion. There was no significant differenceamong the irradiated samples with regard to the sensory properties.Keywords: cuttlefish, filefish, anchovy, gamma irradiation, luminescence

Small artificial reefs (1.2 × 1.02 × 1.1 m) were placed near to (15 m; n = 20) and distant from (500 m; n = 20) larger artificial reefs (1.2 × 2.4 × 2.4 m; n = 20) in July 2008 and 2009, and each set of reefs (two small and one large) was placed 1.7 km apart at a site 28 km south of Dauphin Island, Alabama, in the northern Gulf of Mexico. Divers used visual surveys to identify and count all fish present on the small reefs and estimated fish lengths in 25-mm categories during August 2008, August 2009, and September 2009. Significantly higher numbers of age-0 red snapper Lutjanus campechanus were detected on the small distant reefs (500 m) than on the small nearby (15 m) reefs in all surveys. In addition, significantly higher densities of rock sea bass Centropristis philadelphica and pygmy filefish Stephanolepis setifer were observed on the small distant reefs compared with the small nearby reefs in both August and September 2009. Mean species richness was significantly higher on the small distant ...

We examined feeding preference in the threadsail filefish Stephanolepis cirrhifer on jellyfish and lobworm. Juvenile filefish were fed moon jellyfish Aurelia sp. and/or lobworm Perinereis nuntia vallata for 30 min in tanks with or without sand substrate, and the onset of foraging behavior, response latency (RL) and time spent foraging (total time spent searching for food and feeding) were analyzed using video recordings and measurements of food consumption. Organic matter consumption per unit of foraging time was also estimated for each prey item. In tanks with a sand sub- strate, RL was significantly shorter, foraging time was significantly longer, and organic matter consumption per unit for- aging time was higher for jellyfish than for lobworm; however, the opposite trend was observed in tanks without a sand substrate. Filefish in all treatments consumed an average of 99� 25% of their body weight in jellyfish in 30 min. This study revealed that although filefish prefer lobworm to jellyfish when both are readily available, filefish will select jelly- fish when only jellyfish are visible. These findings imply that frequent jellyfish blooms increase the feeding opportuni- ties of filefish on jellyfish.

We conducted feeding experiments on threadsail filefish Stephanolepis cirrhifer juveniles for 16 days to evaluate the efficacy of moon jellyfish Aurelia aurita as a prey item. Four treatments, each with 40 individuals, were prepared to compare fish growth performance. The treatments consisted of filefish that were starved (control) (S), fed only jellyfish (J), fed only krill (K), and fed both jellyfish and krill (JK). Fish in the S treatment exhibited a 50% mortality rate and reduced body weight, whereas the J treatment exhibited a zero mortality rate and increased body weight. Fish in the JK treatments showed a significantly faster growth than those in the K treatment. Filefish consumed as much as 24 and 13 times their own body weight in jellyfish per day in the J and JK treatments, respectively. This is the first report showing that growth can be sustained by feeding a marine fish only jellyfish, and indicates the potential of jellyfish as a fish prey in both nature and captivity.

The endemic filefish Pervagor spilosoma appeared in exceptionally large numbers throughout the major Hawaiian Islands during the spring of 1985 and remained abundant through 1988. We examined this occurrence with a perspective gained from studies of reef communities at the Island of Hawaii by one or both of us during most years from 1969 to 1994. P. spilosoma is known to vary in numbers, but such great abundances are rare. Although the species is considered a reef fish, individuals constituting the abundance were mostly in the water column, and spread from coastal reefs to the pelagic zone offshore. One might assume they represented an extraordinary recruitment of pelagic juveniles in the process of shifting to benthic habits, but our data indicate a more complex situation. Individuals in the water column tended to be larger than individuals near the reef, and although the former were feeding on plankton when collected, many had shifted to planktivory from earlier feeding on the benthos. Also, many in the water column were ailing, with moribund and dead individuals common, and these tended to carry parasites of types known to induce their hosts to rise toward the surface. We suggest that the great number of filefish we observed above near-shore reefs represented the shoreward fringe of a vast pool of individuals, varied in age, that had accumulated during the exceptionally long pelagic-juvenile period that is characteristic of tetraodontiforms.

Caging and laboratory experiments were used to examine the effect of browsing fish on shell growth of two economically important species of bivalves, the hard clam ( Mercenaria mercenaria Linne) and the bay scallop ( Argopecten irradians concentricus Say). During a 6-week study that was carried out in the fall, clams that were caged with pinfish ( Lagodon rhomboides Linnaeus) had lighter siphon weights (indicating greater siphon nipping pressure) and less shell growth than clams in cages without fish. Average shell growth, however, was ≤ 1.0 mm in both cases, and the difference in shell growth between treatments was ≤ 0.4 mm; a small difference most likely of little biological significance. During a 6-week caging experiment carried out in the summer, clams held in cages with and without browsing pinfish added ≥ 3.0 mm of new shell but showed no difference in siphon weight, body weight or shell growth between treatments. Differences in potential food resources between summer and fall seasons for both clams and fish may have contributed to the observed patterns in hard clam siphon weights and growth rates. Scallop growth was significantly influenced by browsing fish. Juvenile scallops grew about 25% faster when caged with few browsing fish (pinfish and filefish, Monacanthus hispidus (Linneaus)) (ca. 7 fish/cage) compared to those caged with large numbers of browsers (ca. 16 fish/cage). Our field experiments did not allow us to differentiate between tissue cropping and disturbance of feeding activity as the causative agent producing decreased shell growth of scallops. Laboratory experiments, however, demonstrated that scallops spent more time with their valves closed in the presence of browsing fish than did scallops that were placed in tanks without browsers and scallops that were placed in tanks where they could visually and chemically sense the fish but were not physically disturbed by them. This suggests that physical contact between the fish and the scallops was required to cause the scallops to close their valves and stop feeding. A reduction in growth of juvenile scallops when field densities of browsers are high (i.e., in the spring and early summer) may increase susceptibility to predation for juvenile scallops that settle late in the spring.

Investigations conducted off the northern Tunisian coast (central Mediterranean) allowed the authors to collect a male of the unicorn leatherjacket filefish, Aluterus monoceros (L.). The specimen is described in this note, including morphometric measurements and meristic counts. This finding constitutes the first record of A. monoceros off the Tunisian coast and the second record for the Mediterranean Sea. The occurrence of this species in the area and the Mediterranean Sea is discussed and commented.

To demonstrate the species selectivity of fish baskets, fishing experiment was conducted using baskets of iron frame covered with netting in a rocky ground. The baskets were baited with frozen sardine (baited basket) or partly covered with brushwood on their top (covered basket) and their catches were compared with that of the control (without bait and brushwood). The total catch from 156 hauls was much better in the covered baskets and baited ones than in the control. The influence of the bait and brushwood on the catch was fish species selective; the filefish was significantly dominant in the catch of the covered baskets, the grass puffer was caught only by the baited baskets, and no influence was seen in the wrasse and striped catfish. A tank experiment implied that the species selectivity was different between day and night; the rockfish and filefish ingressed preferably into the covered basket in daytime but into the control at night. An exploratory behavior was hypothesized for the ingress of the fishes into the control, and the brushwood was thought to enhance an exploratory drive of fish.

The fish-jellyfish association is regarded as a temporary symbiosis believed to protect the fishes from predators. Here we report on juvenile scads (Trachurus lathami) associated with the jellyfish Chrysaora lactea, opportunistically preyed on by the grouper Mycteroperca acutirostris while the medusa was being damaged. The predation instances occurred when a couple of the filefish Stephanolepis hispidus approached the jellyfish to nibble on its umbrella. The feeding of the filefish caused a momentary disturbance of the defensive association, perceived and capitalised on by the watchful grouper, an opportunistic and versatile hunter. Before and after the disturbance, the protection offered to the young fish by the jellyfish showed to be effective, which strengthens the hypothesis of defensive function of this association. A associação entre peixes e medusas é considerada uma simbiose temporária que protegeria os peixes contra predadores. Relatamos aqui a predação oportunista de juvenis de xixarro Trachurus lathami, associados à medusa Chrysaora lactea, pelo badejo-mira Mycteroperca acutirostris enquanto a medusa estava sendo danificada. Os eventos de predação ocorreram quando um casal do peixe-porco Stephanolepis hispidus se aproximou da medusa para alimentar-se de pequenas porções da sua umbrela. A alimentação dos peixes-porcos causou um distúrbio momentâneo na associação defensiva, percebido e aproveitado pelo atento badejo-mira, um predador versátil e oportunista. Antes e depois do distúrbio, a proteção conferida aos peixes juvenis pela medusa mostrou ser efetiva, fortalecendo a hipótese de função defensiva desta associação.

Very heavy infections of Trichodina spheroidesi apparently killed wild specimens of orange filefish Aluterus schoepfi and whitespotted filefish Cantherhines macrocerus in Puerto Rico. Possibly it is a primary pathogen under some conditions. The hyperparasite Endosphaera engelmanni occurred in this protozoan, and thus the range of both parasites was extended from the temperate zone to the tropics. Sand drums Umbrina coroides, collected off Humacao, Puerto Rico, had heavy infections of Cryptocaryon irritans, which has seldom been shown to injure wild fishes. We have not seen other examples of these diseases in more than 3,000 specimens of 270 species of wild marine fishes examined in Puerto Rico, although Cryptocaryon irritans is common in local marine aquarium fishes. Sharpnose puffers Canthigaster rostrata often cause outbreaks of Cryptocaryon irritans when placed in marine aquaria.

1983年6月から7月にかけ, 壱岐の南西方向の海域一体でウマヅラハギ(Navodan modestus)の大量へい死が発生した。へい死魚は体長9cm前後の小型魚に限られ, 特徴的症状はみられなかった。へい死魚は14尾について細菌学的検査を行ったところ, 全検体魚の腎臓からP.piscicidaが純培養状に分離された。病原性試験では, 復原性(ウマヅラハギ供試)と腎臓等における白点形成(ブリ供試)が認められた。これらの結果, 今回のへい死例は本菌種に起因するものと判断された。

The longnose filefish (Monacanthidae, Oxymonacanthus longirostris) was studied at a patch reef on Enewetak Atoll. It swims with undulations of its median fins and feeds almost continuously on coral polyps, using its beak-like mouth. The spot in the tail resembles an eye so that the tail looks like a head when it protrudes from the coral during feeding. There is slight dichromatism in that males have brighter pelvic flaps. Most of the fish were color tagged for individual recognition. They tended to remain within a given area, although some fish roamed throughout the patch. Most of the larger adults formed monogamous pairs; the smaller fish were variously alone or in groups of 1–5 individuals who appeared to know one another. Only pairs having the largest males, on the periphery of the patch, were clearly territorial. Aggression was a common event featuring a few distinctive displays, most of which were used in courtship as well. Spawning may be a daily event, occurring around 1600 h. The female probes and selects a tuft of blue-green algae; the male nuzzles the female and they spawn in the algae. The green eggs are about 0.7 mm in diameter, demersal, adhesive, and hidden in the algae; they hatched in 53.5 h, just after sunset. The planktonic larvae fit the monacanthid type B of Leis & Rennis (1983) and were initially 2.5 mm TL; by day 5 their yolk was gone.

Seasonal and annual population fluctuations of Rudarius ercodes in the Zostera bed in Odawa Bay were studied. A recruitment group of small sized fish occurred every summer and grew into large sized fish by spring of the following year. The number of catch per haul of each recruitment group was used as an index of relative population density. From the seasonal changes of this index, three peaks were observed in September-October, May-June, and August-September at the head of the bay and in October-November, April-May, and August-October at the mouth of the bay. In winter only a few individuals stayed at the monuth and none at the head of the bay, although they were distributed in both areas in other seasons. From the change of the number per haul of three recruitment groups at each peak, it was found that the great annual population fluctuation at the first peak decreased gradually and the population level approached about 100 individuals per haul at the third peak. These facts suggest the possiblilty of movement in and out of the bay and some process of population regulation.

This project was undertaken as a part of the OTEC environmental studies plan on the toxicity of OTEC working fluids to marine organisms. Ammonia and chlorine were chosen as they pose the greatest potential environmental threat. Acute and chronic bioassays determined the LT/sub 50/, LC/sub 50/ and the behavior of mullet (Mugil cephalus), sargassum shrimp (Latreutes fucorum) and filefish (Monocanthus hispidus).

IN view of the paucity of records of the globefish, Lagocephalus lagocephalus (L.), around British coasts, it seems worth while recording the recent occurrence of a specimen at Tenby, Pembrokeshire. According to information supplied by Mr. A. L. Leach, it was found alive on September 6 in a pool on the South Sands, Tenby; its length from snout to fork of caudal fin is 14½ in. The colours of the dead specimen are as described by Day in “The Fishes of Great Britain and Ireland”, but Mr. Leach states that the skin of the expansible ventral surface of the living fish appeared distinctly pinkish. Of the thirteen or fourteen British specimens of this tropical species listed by Day, nearly all were taken on the south coast; though there is one Welsh record from Amroth near Tenby, and two records from the Orkneys.

Observations are presented of the effects of winter water conditions on the survival, behavior and color patterns of 15 species of marine fishes, comprising 11 families and 80 specimens held in aquaria with continuous flowing water. Only weakfish were found to float when dead, all others remained on the bottom of the test aquaria. The behavior patterns exhibited prior to death were as varied as the species studied. These observations may help to explain aggregations of dead fishes that are often detected accidentally during winter sampling. The largest kill of the study specimens occurred during the 15-20 December, 1962, cold snap. Field observations froin Georgia to Texas reported kills of several of the same species. Schwartz (1963) pointed out the need for observations on the effects of low temperature waters on the behavior and survival of marine fishes as a prelude to speculations regarding natural calamities. This paper gives further observations and presents data on 15 species of marine fishes, comprising tt families and 80 specimens, which were subjected to natural winter water temperatures and salinities. Specimens were obtained from pound nets near the mouth of the Potomac River, Smith Point, Virginia, on 25 September, 1962. A boat, equipped with two circular tanks, six feet in diameter and three feet deep, which were supplied with Chesapeake Bay surface water, was used to transport the fish the 20 miles to the Chesapeake Biological Laboratory. Temperature and salinity conditions at the time of capture at Smith Point were 20.7 C and 19.5 ppt. The fish were transferred into four-foot-square indoor aquaria, with unfiltered, flowing water (20.2 C and 16.1 ppt) pumped from the Patuxent River, Solomons, Maryland. Distribution of the fish in the aquaria was as follows: Tank 1, cownose ray, southern stingray and sharksucker; Tank 2, kingfish, croaker, red drum and stargazer; Tank 3, spot, filefish, striped burrfish and weakfish; Tank 4, black sea bass, spot (small), searobin and swellfish; and Tank 5, toadfish. Beaven (1960) reported the general salinity and temperature conditions observed at Solomnons over a 20-year period. Salinities during the observation period and their relationship to 25-year averages are illustrated in Figure t. The oxygen conditions of the water in the aquaria were always more than adequate for fish survival. Generally, the fall and winter of 1962-63 was colder than usual. The Chesapeake Bay to Point Lookout was frozen completely over on 18 February, 1963, for the first time since 1934. Ice, 6-10 inches thick, prevailed from the head of the Bay to James Island (62 nautical miles). A one-quarter to one-inch thickness of ice covered the Bay southward another 20 nautical miles to Point Lookout. 1 Contr. No. 246. Natural Resources Institute of the University of Maryland, Solomons, Maryland.