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The contamination of the aquatic systems with heavy metals from natural and anthropogenic sources has become a global problem which poses serious threats to ecosystems and natural communities. Heavy metals get bio concentrated in organisms that may cause health problems in humans via the food chain. The heavy metal zinc causes most serious environmental contaminations and effects due to its rampant use. In this study, sublethal effects of the heavy metal, zinc on the histopathological parameters in fresh water fish, Etroplus maculatus was investigated. The 96 hour LC50 value of zinc was determined by Probit analysis, that was found to be 12.4 mg/L. The liver and kidney samples were collected from fish was exposed to sublethal concentrations of zinc on 14th and 28thdays.The structural deformities observed in the liver tissue showed swelling of hepatocytes, vacuolar degeneration, necrosis, nuclear hypertrophy and cirrhosis with acute haemorrhage whereas, kidney showed degenerated renal capsule and renal tubule, edema, necrosis and haemorrhage in the interstetium. The histpathological changes become prominent as the days and concentration of exposure increases. The study thus establishes that zinc is harmful to Etroplus maculatus even in sublethal concentrations and effective management strategies are to be evolved and implemented to protect our water bodies and the organisms from problems of heavy metal pollution.

This paper characterize microplastics (MPs) in the heavily urbanized, brackish water Vembanad Lake (India), focussing on some commercially important bottom-feeding fishes and shellfish (Arius maculatus, Etroplus suratensis, E. maculatus and Villorita sp.). The average abundance of MPs was higher in the water column (872 ± 573 nos./m3) than in finfishes (15 ± 13 particles per fish) and shellfish (23 ± 20 nos./ind.). Fibre was the most abundant MP type in the water and the organisms examined. The size of MPs obtained from finfishes ranged between 0.04 and 4.73 mm (4 ± 3 mm), with a majority of particles being

The present study was designed to evaluate the effects of nonylphenol in the pro-oxidant/ antioxidant system in ovary of the cichlid fish Etroplus maculatus. Fishes were exposed at two sublethal concentrations (one-fifth and one-tenth of LC50) of nonylphenol for 24, 72 and 96 h maintaining control groups. The oxidative stress indices as the activities of antioxidant enzymes, superoxide dismutase, catalase, glutathione reductase along with the levels of hydrogen peroxide generation and lipid peroxidation were monitored in concentration-and time-dependent manner. Activity of superoxide dismutase significantly (P

The present study was carried out to analyze the possibility of practicing aquaculture in selected mangrove regions in Jaffna, Sri Lanka. A detailed study on the possibility of undertaking aquaculture has been carried out in Sarasaalai and Kapputhu mangrove regions. The water quality parameters were measured, organic matter was estimated and available fish species were collected and identified during the study period. Samples were collected in the second week of each month from June 2016 to November 2016. Water quality parameters such as water temperature, salinity, pH, dissolved oxygen, water depth and turbidity were measured. Organic matter was estimated for soil samples collected from the study areas. Water quality parameters were analyzed by two sample t-test using minitab13. Identification of all collected fish species were confirmed according to the standard literature by observing their morphological and meristic characters. Statistical analysis shows no significant difference between Sarasaalai and Kapputhu in water temperature (P = 0.062), salinity (P = 0.402), dissolved oxygen (P = 0.773), pH (P = 0.262) and water depth (P = 0.798). Significant difference (P = 0.001) was observed for turbidity in both locations. High percentage of organic matter was observed in Sarasaalai. The identified fish species in both locations were Chanos chanos, Platycephalus fuscus, Oreochromis mossambicus, Nematalosa nasus, Hyporhamphus limbatus, Hemiramphus marginatus, Etroplus maculatus, Gerres abbreviatus and Gerres oyena. The most abundant species found in Sarasaalai was O. mossambicus and in Kapputhu were O. mossambicus, C. chanos, G. abbreviatus and G. oyena. The present investigation inferred that the specified species can be cultured in the said regions. However, a long term study on seed resources, environmental and climatic conditions of particular site would ensure more details on culture aspects of these species.

Quantitative recordings were made of the behaviour of Etroplus maculatus parents caring for eggs and wrigglers. Spatial and temporal aspects of brood relief behaviour are examined in connection with parent size, time of day, interval since spawning and the frequencies of occurrence of other behaviours. Function aspect of Cichild brood relief behaviour are discussed and compared with those of avian nest relief.

Prevalence of antibiotic resistance among gut associated bacteria of two indigenous freshwater ornamental fishes were analyzed in this study. A total of 56 bacteria was isolated from the gut of Aplocheilus lineatus and Etroplus maculatus . Total viable count (TVC) of heterotrophic bacteria ranged between 1.7 x 10 6 to 6.8 x 10 6 and 0.2 x 10 4 to 0.65 x 10 7 cfu per gram in gut of Etroplus maculatus and Aplocheilus lineatus respectively. Predominant genera encountered in the gut of A. lineatus were Lactobacillus , Bacillus , Micrococcus , and Aeromonas , while that of E. maculatus was dominated by Micrococcus followed by Bacillus , Lactobacillus and Vibrios . The isolates were subjected 11 different antibiotics belonging to 7 different classes such as aminoglygocides (streptomycin, gentamicin), quinolones (nalidixic acid), fluorquinolones (ciprofloxacin), tetracyclines (tetracycline), penicillin (carbenicillin), cephalosporins (cephalothin, cefpodoxime), sulphonamides (sulfafurazole, trimethoprim). Antibiotic resistance among the gut associated bacteria from A. lineatus was relatively lower when compared to those from the gut of E. maculatus . Multiple antibiotic resistance (MAR) indexing of the isolates revealed that nearly 50% of the bacterial isolates of E. maculatus were multiple drug resistance, while in A. lineatus it was found to be 38.41%.The MAR index of the isolates ranged from 0.09 - 0.36 in A. lineatus ; 0.09 - 0.63 in E. maculatus. While most isolates from the gut of both the fishes were resistant to Cefpodoxime, none of the isolates were resistant to Gentamicin. Though the prevalence of antibiotic resistance among gut of these indigenous fishes are relatively lower when compared those from the gut of cultured ones, considerable pollution of the natural waters are providing ideal environment for the emergence of drug resistance mutants and subsequent colonisation in the gut of fish fauna of these waters.

Six species of ergasilid copepods are described, based on material found on 11 species of fishes collected from estuaries and rivers in Kerala, India. Five are new to science, they are: Dermoergasilus varicoleus n. sp. from Liza tade Forskal; Ergasilus parvitergum n. sp. from Etroplus suratensis (Bloch) and Caranx malabaricus (Bloch and Schneider); Ergasilus rostralis n. sp. from Liza tade, L. macrolepis (Smith), and Valamugil seheli (Forskal); Ergasilus uniseriatus n. sp. from Glossogobius giuris (Hamilton) and Xenentodon cancila Hamilton; and Paraergasilus dentatus n. sp. from Glossogobius giuris. Dermoergasilus amplectens (Dogiel and Akhmerov) was recovered in India from six species of hosts: Etroplus maculatus (Bloch), Gerres setifer (Hamilton), Hyporamphus xanthopterus (Cuvier and Valenciennes), Megalops cyprinoides (Broussonet), Valamugil seheli (Forskal), and Chanos chanos (Forskal).

The life cycle of the cyathocotylid fluke, Mesostephanus indicum Mehra, 1947 infecting the pariah kite, Milvus migrans govinda (Accipitridae), is elucidated. The species, reported by Mehra (Proc Nat Acad Sci India 17:1–52, 1947) from Buteo rufinus rufinus (Accipitridae), was transferred to the genus Prohemistomum by Dubois (Rev Suiss de Zool 58:639–691, 1951). However, it is retained in the genus Mesostephanus because of the presence of vaginal sphincter and caudal appendage, which are the characters of the genus. Its first intermediate host is the gastropod snail, Bellamya bengalensis (Viviparidae), which released the furcocercous cercariae. The prohemistomulum-type metacercariae encysted in the muscle tissues of the freshwater fish Rasbora daniconius and Puntius sophore (Cyprinidae), Mystus malabaricus (Bagridae), Heteropneustes fossilis (Heteropneustidae), Aplocheilus lineatus (Cyprinodontidae), Etroplus maculatus and E. suratensis (Cichlidae), and Pseudosphromenus cupanus (Belontidae). Recovery of M. indicum from M. m. govinda forms a new host record, and this is the first report of the life cycle of the genus from India.

members of the family Cichlidae, which contains 24 of the 28 species known to exhibit parent/juvenile physical contact of any kind. Of the four noncichlid species, two are freshwater catfishes (Bagridae) that have elongate filliform processes on the ventral surface of the male which secrete a milky proteinaceous fluid on which the young feed (Sundararaj, 1916, in Noakes, 1979). Another of these species is an Amazonian osteoglossid (Arapaima gigas) whose parent-juvenile contact behavior is apparently under dispute; no specific juvenile behaviors are described for this species in published references (Noakes, 1979). The fourth noncichlid species, and the only marine species, is Acanthochromis polyacanthus (Pomacentridae). The glancing behavior of juvenile Acanthochromis (a monotypic genus) bears a superficial resemblance to that recorded for cichlid species such as Etroplus maculatus or Cichlasoma citrinellum (Ward and Barlow, 1967; Noakes and Barlow, 1973; Robertson, 1973). This behavioral similarity of Acanthochromis to many cichlids is remarkable not only because of its novelty but also because of the possible ancestral connection between the Pomacentridae and Cichlidae

In addition to the many trophic groups of haplochromine cichlids already known from Lake Victoria, two new ones (i.e. zooplanktophages and cleaner fishes) have been discovered by the Haplochromis Ecology Survey Team which operates in the Mwanza Gulf of the Lake. The present paper deals with the taxonomic description and eco-morphology of the two (new) species of haplochromine cleaner fishes. Cleaning symbiosis has been described mainly for marine fishes. Among cichlids only juvenile Etroplus maculatus were known as (facultative) cleaners 1 . The cleaning behaviour of the Victoria haplochromines is deduced from their stomach contents which revealed that one species feeds mainly and the other partly on carplice and leeches. No other cleaner fishes are known to feed on these kinds of parasites which in Lake Victoria occur externally on smooth-skinned fishes (Protopterus aethiopicus, Bagrus docmac, Synodontis sp. and Clarias sp.). The preference for firmly attached, flat parasites correlates with the scraper-like teeth of the haplochromine cleaners. Virtually all other cleaner fishes have teeth with pronounced, pointed cusps and feed on mobile parasites or (elongate) parasites which are only proximally attached to their hosts.

Behavioural data were collected from control and experimental pairs of orange chromides, from pairing to the time of spawning. Experimental females had their pelvic fins surgically removed at the time of pairing. The pelvic fins were found to be necessary for equidistant egg placement at the time of spawning. Recently developed cartographic techniques were modified for the data analysis to verify the results statistically and visually. The spawns of control females were of uniform density and egg placement was equidistant. The spawns of experimental females were of variable density and egg placement was not equidistant. Female pelvic fin flickering does not appear to be a socially significant courtship activity. The frequency of courtship behaviours and significant behavioural transitions were nearly identical for control and experimental pairs.

YoungEtroplus maculatus andPelmatochromis subocellatus kribensis were reared on diets of low, medium, or high quantities of food and the ontogeny of behavior documented until fish matured. Data were categorized into: (1) from the beginning of the experiment to the midpoint (100 days forE. maculatus and 118 days forP. s. kribensis); and (2) from the midpoint to maturity. For both species the tendency to be territorial, as deduced by the numbers of territories defended, or number of charges or rams performed, was explained by a unimodal relationship between territorial tendency and food available per gram of fish. Young fish receiving low quantities of food were highly territorial, but as they grew and food available per gram of fish decreased, they gave up territorial behavior. Young fish receiving high quantities of food were not territorial initially, but as they grew became increasingly territorial. Fish receiving intermediate quantities of food always defended territories. Lateral displays were performed most often by fish receiving intermediate quantities of food apparently because they were ambivalent being close to either the lower or upper thresholds for territoriality.

Effects of osmotic stress on the branchial Na+−K+-ATPase activity in two freshwater euryhaline teleosts (the tilapia Sarotherodon mossambicus Peters and the orange chromid Etroplus maculatus Bleeker) were studied. Direct transfer from fresh water to salt water with a salinity of 35‰ S caused extensive mortality in tilapia. Of the remaining four saltwater concentrations (4.375, 8.75, 17.5, and 26.25‰ S), the higher two increased the enzyme activity significantly in the first week without affecting it further during the remaining seven weeks of acclimation. The lower two concentrations failed to elicit any significant change. In the case of orange chromid, all three salt-water concentrations (4.375, 8.75, and 17.5‰ S) which the fish survived produced a more significant and extensive change in the enzyme activity, which continued to rise during the entire acclimation period. Employing a procedure of gradual transfer, tilapia and orange chromid were successfully adapted to saltwater concentrations of up to 61.25 and 35‰ S, respectively. In this experiment, almost each successive increase in salinity elevated the enzyme activity further, but the total change in both species was considerably less extensive than might be expected from the direct transfer study. When the freshwater fish were transferred to identical concentrations of pure NaCl or whole ocean salt, the former produced a relatively greater change in the enzyme activity in tilapia. No such difference was seen in orange chromid. During reacclimation of the saltwater-adapted fish to fresh water, the enzyme activity began to decrease immediately in both species, but remained above the freshwater control levels at the end of eight weeks.

Increased aggressive activity between ♂ and ♀ in isolated pairs of Etroplus maculatus. has hitherto been explained either by the drive hypothesis or by the external stimulus hypothesis. In an attempt to investigate these two hypotheses the partners of 48 pairs were separated and their aggressiveness towards their mirrored images and their non-aggressive activities were recorded the following day and again 4 days later after 180 brief presentations of an adjacent compartment. For both sexes aggressiveness was lowered if this compartement was empty (isolation) and heightened if it held the original mate. ♂y also reacted more aggressively on seeing conspecific strangers of both sexes. There was no significant alteration of non-aggressive activities in any of the series. The increase of aggressiveness caused by the presence of the mate was normally offset by various investigated mechanisms preventing its eruption against the partner. Attacks only occurred if the equilibrium between aggressiveness and inhibition was disturbed. All results and those of other authors are discussed; it is concluded that the behaviour of E. maculatus. can be better explained in terms of external stimulation than in terms of an endogenous production of aggressive drive energy.

Initial adaptive responses in the oxygen consumption to warm and cold stress was studied at the organismal level in two species of eurythermal freshwater teleosts,Etroplus maculatus andCirrhina reba. E. maculatus, studied during the summer months, was found to acclimate completely to warm (35° C.) and partially to cold (20° C.). As against this,C. reba, studied during the winter months, was found to acclimate partially to warm. Cold acclimation could not be studied in this species. These differences are discussed in the light of the previous thermal history of these fishes and the thermal gradient imposed in each case.

There is an increase in the number of the so-called ‘chloride cells’ in the gill epithelium with increasing salinity of the medium. In 75% and 100% sea-water the ‘chloride cells’ exhibit a change in structure, in that they become more granular and acquire an apical vacuole. There is also a general decrease in the number of mucous cells with increasing salinity of the medium of adaptation. The glomerulus tends to become smaller in the fishes adapted to high salinity as compared to the fresh-water fish. There is also a deposition of pigment around the nucleus and an indication of some changes in the nucleus of the kidney tubule cells in fishes adapted to 100% sea-water. In the intestine, adaptation to high salinities results in an increase in the nuclear size of the columnar epithelial cells, an increase in the number of flask-shaped cells, and a considerable increase in the thickness occupied by the tunica propria.

1. Fin-flickering (calling) is exhibited only by adult fish when they are caring for the young. This behavior is especially frequent when the parents are alarmed. The calling frequency of the parents was as much as 17 times greater during disturbed conditions than during undisturbed conditions. 2. During disturbed conditions the duration and frequency of calling were significantly greater on the third day that the fry were free-swimming than on any of the other test days. This increase in calling is discussed in connection with other behavioral and histological changes that have been deported to occur on day 3. 3. The parents alternate in the care of the school. The times spent with the school by each parent are not significantly different whether observed during disturbed or undisturbed conditions. 4. On each test day the vertical and horizontal dispersion of the school decreased as calling increased, causing the school to become more compact. The distance from the center of the school to the parent changed significantly only on day 6 of free-swimming, decreasing as calling increased. 5. During the free-swimming stage of development the fry make continual physical contact with the body of the parents, a behavior termed glancing. Glancing rates were unaffected by changes in calling frequency on days 1 and 3 of free-swimming. However, on day 6 and on subsequent days glancing decreased as the calling frequency increased. 6. The changes in school activity as a function of increased calling, which were seen on day 6 but not on day 3, are discussed in light of their adaptive significance.

Summary Two distinct motor patterns have been found to be used by young E. maculatus in making physical contact with their parents, a behaviour termed earlier as ‘glancing’. One motor pattern is an oral contact between the mouth of the fry and the body of the parent, micronipping, while the other motor pattern is a chafing motion of the mid-body of the young against the body of the parent, which we call glancing. The rates for micronipping and glancing are similar on the first 3 days of free-swimming, but from the 4th to the 7th day micronipping is performed at a considerably higher rate than glancing. After day 7, the rate of micronipping continues to decline until day 12 and then remains at a low level. Glancing remains at a low rate until the 8th day of free-swimming, but then it steadily increases to its highest rate on day 18. The fry do not uniformly contact the body of the parent. The majority of both micronips and glances are directed to the ventral portion of the parent fish throughout the 21-day observation period. There are definite anterio-posterior shifts in the location of contacts during ontogeny. Micronipping is predominantly an anteriodorsally directed behaviour, while glancing is a posterio-ventrally directed behaviour. The rate of glancing prior to feeding young fry remains constant and does not change with age. The rate of glancing 90 min after feeding increases as a linear function of fry age, and the performance observed during the 3rd week of free-swimming is almost triple that observed at the end of the 1st week. The rate of micronipping prior to and after feeding are not significantly different. Both decrease as a linear function of age. It is hypothesized that both micronipping and glancing serve as a means of stimulating the parents and thereby keeping them in a parental condition. Previous accounts have established that the parents secrete abundant mucus during the time when micronipping is most frequent. It is concluded that micronipping results in the ingestion of parental mucus, whereas glancing functions to induce schooling; thus the latter facilitates the maintenance and protection of the school.

1. Carbonic anhydrase in the gills of the freshwater teleost,Etroplus maculatus, was demonstrated to be influenced by transfer of the animal to saline media.

Mechanisms of salinity acclimation in the euryhaline freshwater living teleost, Etroplus maculatus (Bleeker), were studied. Brain water content decreased steadily with increasing salinity of the medium. Liver and muscle water content increased initially in 30% sea-water but in higher salinities decreased markedly, approximating control levels. Osmotic pressure of tissue fluid increased by 33% from 0.45% NaCl equivalent in freshwater to 0.60% NaCl equivalent in 100% sea-water. K and Mg decreased in dilute saline media but in 100% sea-water increased markedly approximating control levels; this is especially so in regard to Mg. Na decreased steadily and Ca increased with increasing salinity. Cl increased in 60% sea-water but decreased in 100% sea-water; however, its concentration in 100% sea-water exceeded that in freshwater. Free amino acids increased by 11% in 30% sea-water but decreased in 60% and 100% sea-water, such that their concentration was lower by 28% in 60% sea-water and by 34% in 100% sea-water relative to the control level. Ascorbic acid decreased by 37% in 30% sea-water but in 60% and 100% sea-water increased steadily approximating the control level. The significance of these changes in the physiology of salinity acclimation is discussed and a correlation suggested between acclimation to salinity and to high temperature.

Effects of starvation on the oxygen consumption was studied in two species of fresh water fish, Etroplus maculatus and Cirrhina reba . In both the species oxygen consumption attained a new level after the initial decrease. In C.reba there was a slight increase in the oxygen consumption following the initial decrease upto about the 32nd day.

Abstract I. During the parental period (3 to 4 weeks) young Etroplus maculatus skim or bounce against the body wall of the parent, a response termed glancing. 2. The glancing rate for the individual does not change during the first week of free-swimming but thereafter it increases; the increase, however, is only apparent in fry that have been fed. The glancing rate for the school decreases during the first week but this is due to mortality. 3. The individual glancing rate is independent of the number of individuals within a school (25-125 individuals) regardless of age. 4. Hour-to-hour changes in glancing rate also occur and are related to the time of feeding. 5. The orientation of glancing when characterized by 3 divisions, a ventral, a medial, and a dorso-anterior division, remains unchanged during development. 6. The orientation of glancing, when characterized by an anterior and a posterior division, shows definite ontogenetic changes. The anterio-posterior changes in orientation are reinacted each day, but steadily less so as the fry become older. 7. Feeding does not change the glancing rate for individuals about 7 days old or less, but it increases the amount of glancing 1.6-fold for fry 12 days old and 2.2-fold for fry 18 days old. The hour-to-hour changes in glancing rate can also be predicted from pre-feeding performance. 8. Feeding affects the school organization. After feeding the school becomes more uniform, moves closer to the parent, and as it does the young glance more. 9. Fry with normal parental care undergo progressive morphological changes. Fry deprived of parental care have a high mortality rate, while growth and morphological differentiation are severely retarded. After 9 days of parental care, fry have completed the major morphological changes and can survive independently of the parent. 10. During the early free-swimming days of the fry, the number of mucus glands in the epidermis of the parent increases by 34%. 11. When parents were coated with carbon powder it was shown that young actually eat from the parents' side when glancing, and presumedly eat mucus. 12. The changes in behavior during development are discussed with regard to the possible mechanisms by which feeding influences glancing rate, causal factors that might affect orientation of glancing, and the possible functional and ecological significance of this behavior.

1. In its natural habitat (fresh water) E. maculatus had VP 5152 (porphyropsin) as the predominant visual pigment. 2. On acclimation to 100% sea water VP 4951 (rhodopsin) was found to be predominant. 3. On acclimation to 50% sea water the visual pigment system of the fish presented a transitory phase. 4. The significance and implications of these results in relation to the earlier work is discussed.

Une maladie virale de E.m. provoquant des branchies et mortelle a ete etudiee du point de vue histopathologie

The effects of monochloramine on frequencies and sequences of courtship modal action patterns (MAPs) and egg and spawn measurements in Etroplus maculatus were studied. Frequencies of several MAPs were significantly different among groups of fish exposed to no toxicant, 0.025 and 0.050 mg 1-1 monochloramine. Length of courtship, number of eggs and egg density per spawn were found to differ significantly between control fish and those exposed to monochloramine. Fish exposed to 0.050 mg 1-1 did not reproduce at all. Sequential analyses of courtship behavior described significant differences in courtship sequences among control fish and those exposed to the toxicant. It is concluded that sublethal levels of monochloramine alter courtship behavior and decrease reproductive success

Physiological studies revealed that agitation (simulated fanning) of the brood results in increased oxygen consumption, increased developmental rate and general promotion of brood success. It was also found that the more intense the agitation (excursions per minute) the greater the metabolic rate is enhanced. Embryos exposed to continual agitation hatched approximately twenty hours in advance of non-agitated eggs. Temporal studies of fanning activity in Etroplus maculatus showed significant differences between pairs breeding in colonial situations as compared to those breeding in isolation. Parental behaviors were recorded throughout egg care until hatching. Two types of ventilatory behaviors were described: active fanning and passive fanning. Pairs breeding in isolation invested more time in long passive bouts and less time in short active bouts. Conversely, colonial parents fanned predominately with short active bouts and displayed no prolonged passive fanning. Surprisingly, no differences were apparent in either reproductive success or hatching time between isolated and colonial pairs in this study. Orange chromides readily nested in two extremely different situations. They also displayed significantly different fanning regimes, behavioral time budgets and transitions of behavior; yet they were equally successful. Parental orange chromides can modulate their ventilatory activities in response to the contingencies of their nesting situation which ultimately allows them maximization of reproductive success.

Reproductive effort in fish through the time of spawning should include effort spent in producing gametes, territorial defense and courtship. This investment may be repeated if eggs are lost or the pair is separated after spawning has occurred. Little is known about how investments change when fish repeat reproduction. This study examined some changes in gamete production and courtship as initial pairs of orange chromides,Etroplus maculatus, were successively cycled with new partners after spawning had occurred. Results indicate that males' fertilization rate remained the same throughout all cycles. Females' egg number and total egg mass production also remained the same. However, the quality of individual eggs decreased significantly with every successive cycle. Changes in courtship behavior were also documented for some modal action patterns. It appears from these results that there are definite changes in both courtship and spawning characteristics from cycle to cycle. Therefore, the reproductive effort as a whole may change. In turn this may help select for the type of reproductive strategy observed in nature.

Colleagues and friends of Jack A. Ward were deeply saddened by his recent death on December 5th, 1982 due to a coronary thrombosis. Jack was born on September 2nd, 1935, in Lebanon, Oregon, the son of Tellis and Vena Ward. His youth was spent in Lebanon where he attended high school. He earned a Bachelor of Science in 1957 from Willamette University and in 1960, a Masters of Science at the University of Washington. He earned a Doctor of Philosophy at the University of Illinois in 1965, working under Dr. George Barlow on the now widely known orange chromide, Etroplus maculatus.

1. 1. Water content increased on warm acclimation in the brain, liver and muscle by 4·6, 8 and 3 per cent respectively; it decreased on cold acclimation by 2·3 and 0·6 per cent in the brain and liver but increased by 1·9 per cent in the muscle. 2. 2. Osmotic pressure of tissue fluid remained almost constant at 0·45 per cent NaCl equivalent despite thermal acclimation. 3. 3. On cold (20°C) acclimation K increased by 12 per cent and Ca by 95 per cent, while Na and Mg decreased by 10 per cent each, Cl by 49 per cent and free amino acids by 28 per cent. 4. 4. On warm (35°C) acclimation Mg increased by 8 per cent, Ca by 10 per cent; Na decreased by 16 per cent, K by 8 per cent and Cl by 40 per cent. A slight decrease in free amino acids by 13 per cent was also noticed. 5. 5. Ascorbic acid increased by 89 per cent on cold acclimation and decreased by 28 per cent on warm acclimation. 6. 6. The Possible significance of these changes in the metabolic compensation to thermal stress is discussed.

Background: Cichlid fishes show considerable diversity in swim bladder morphology. In members of the subfamily Etroplinae, the connection between anterior swim bladder extensions and the inner ears enhances sound transmission and translates into an improved hearing ability. We tested the hypothesis that those swim bladder modifications coincide with differences in inner ear morphology and thus compared Steatocranus tinanti (vestigial swim bladder), Hemichromis guttatus (large swim bladder without extensions), and Etroplus maculatus (intimate connection between swim bladder and inner ears). Methodology and results: We applied immunostaining together with confocal imaging and scanning electron microscopy for the investigation of sensory epithelia, and high-resolution, contrast-enhanced microCT imaging for characterizing inner ears in 3D, and evaluated otolith dimensions. Compared to S. tinanti and H. guttatus, inner ears of E. maculatus showed an enlargement of all three maculae, and a particularly large lacinia of the macula utriculi. While our analysis of orientation patterns of ciliary bundles on the three macula types using artificially flattened maculae uncovered rather similar orientation patterns of ciliary bundles, interspecific differences became apparent when illustrating the orientation patterns on the 3D models of the maculae: differences in the shape and curvature of the lacinia of the macula utriculi, and the anterior arm of the macula lagenae resulted in an altered arrangement of ciliary bundles. Conclusions: Our results imply that improved audition in E. maculatus is associated not only with swim bladder modifications but also with altered inner ear morphology. However, not all modifications in E. maculatus could be connected to enhanced auditory abilities, and so a potential improvement of the vestibular sense, among others, also needs to be considered. Our study highlights the value of analyzing orientation patterns of ciliary bundles in their intact 3D context in studies of inner ear morphology and physiology.

LD50 exposure of a teleost fish.Etroplus maculatus, to Sumithion depressed the rate of oxygen consumption, concomitantly with an inhibition in succinate dehydrogenase activity in the tissues, in the order gill>brain>liver>muscle. The effect of the same pesticide on the activity of acetylcholinesterase was quite interesting, with a maximal inhibitory effect on the brain followed by liver, muscle and gill, suggesting a tissue specificity, and a differential sensitivity of the enzyme towards the pesticide.

Young of the cichlid fish Etroplus maculatus actively clean all age groups of Etroplus suratensis. E. suratensis are naturally inhibited from attacking small fish while E. maculatus do so frequently. Cleaning territories are established by the young E. maculatus. Cleaning activity shows a daily circadian rhythm. Removal of fungus from fins and tail appear to be an important adaptive function of this symbiosis. The unique behavior during parental care of both species and other specific behavioral traits may have aided in the evolution of the relationship. This represents the first report of a cleaning symbiosis involving cichlid fish.