Nighttime migrations and behavioral patterns of Pempheris schwenkii

Background Although the biomass of the nocturnal fishes is almost same as that of diurnal fishes, most of the ecological studies that examine feeding or reproductive behaviors are on diurnal fishes. Therefore, there is limited ecological information regarding the nocturnal fishes. This fact may be attributed to the difficulty in observing them during darkness. Members of the genus Pempheris (Pempheridae) are one of the most abundant nocturnal fishes on coral reefs. Methods The nighttime migrations of Pempheris schwenkii were observed by attaching a chemical luminescent tag. Tagged fishes were followed by an observer without torch and SCUBA, and their positions and estimated depths were plotted on an underwater topographic map. Aquarium tank observation was carried out to further describe their habits during the night. Results The new tagging method provided good data for observing the migration behavior. In all five observations, the target fishes started nighttime migration from the entrance of their cave within 1 h after sunset. All of them immediately left the inner reef and spent most of the observation time near the surface (0–5 m depth) or shallow (5–15 m depth) water-columns of the outer reef. Their migration pattern varied between days, but they migrated long distance (379–786 m/h) during each observation. The behavior observed in the aquarium tank was categorized into five patterns: schooling, shaking, migrating, spawning, and feeding. Shaking and spawning were observed during one of three observation days. Discussion The present study firstly clarified the small-scale but dynamic nocturnal migration pattern of P. schwenkii in nature by a new method using chemical luminescent tags. In addition, combined observations from nature and an aquarium could be used to estimate the behavior of this species. Pempheris schwenkii may reduce their predation risk of eggs and adults by spawning at outer reef in nighttime. It was estimated that they can potentially migrate 4–7 km/night. The rapid growth known for this species may have been supported by their feeding behavior where they can fill up their stomach every night with rich zooplankton in outer reefs. Furthermore, the behavior of this species indicates the possibility that they make an important contribution to the flow of energy and materials in their coral reef ecosystem.

Evaluation of the ameliorative roles of Vitamins A, C and E on reduced glutathione in Clarias gariepinus (Burchell, 1822) fingerlings exposed to cadmium chloride

Effects of cadmium chloride on the production of antioxidants such as reduced glutathione (GSH) in Clarias gariepinus and how such effects can be ameliorated through administration of vitamins were investigated. C. gariepinus fingerlings were exposed to sub-lethal concentrations of Cd (00, 12mg/L, 16mg/L, 20mg/L and 24mg/L) with replicate in each case. 12mg/L each of the vitamins were administered across all bud. Fresh concentrations of both toxicant and vitamins were administered every 72 hours for a period of 12 weeks every time the water medium was changed. 3 samples of the fish were randomly selected and sacrificed from each aquarium tank every 2 weeks. The gills, kidneys and liver were excised from these specimens, homogenized in sodium phosphate buffer and then assayed for GSH production levels in each case. From the results: In Cd only group, the highest GSH level produced in the liver was 38.85±0.07µg/ml. In the liver of samples of CdVA group, the value (93.97±0.07µg/ml) increased then followed by the gill (67.72±0.13µg/ml). In CdVC, the GSH production level in the gill (39.76±0.07µg/ml) was relatively higher than livers and kidneys of the samples. In CdVE, the kidney produced the highest GSH value of 32.89±0.10µg/ml. The elicitation and utilization of the antioxidant at one point or the other were adopted by the fish in dealing with the effects of the toxicant especially in the presence of the vitamins. Higher concentrations of the vitamins could facilitate the understanding of the effects of the vitamins in mitigating the effects of the toxicant.

The Effect of reversing the Internal Water-Current on the Spicule Orientation in Leucosolenia variabilis and L. complicata

1. Specimens grown in quiet water in an aquarium tank produce the same pattern of spicules as do those occurring naturally. Woodland's hypothesis, that the orientation arises from turbulence in the environment, is thereby disproved. 2. Reversing the internal water-current in excised oscular tubes of Leucosolenia has shown that no direct causal relationship exists between the direction of the current and the orientation of the spicules. 3. The spicule arrangement is modifiable by experiment; the orientation is not dependent on the existence of static structural features in the wall of the sponge. 4. Removal of the oscular rim has little effect on the orientation of the spicules subsequently developing in the tube behind. 5. Diverticula develop from bulges, formed largely by a reshaping process. The arrangement of the associated small spicules is essentially the same as for L. lieberkühnii. 6. A mechanical hypothesis explaining the orientation of the spicules is briefly described. The formative cell sextet is believed to be oriented by a movement of the mesogloea over the epithelium to which the sextet is contiguous.

Stanley Wells Kemp, 1882-1945

In the years of war we have become sadly accustomed to news of young lives cut short before they could fulfil the promise that we saw in them. The tragedy of Stanley Kemp’s death was of a different order. In the prime of life, at the full height of achievement and reputation, he was struck down by an insidious malady, concerning which medical science can, as yet, give no counsel for avoidance or cure. Stanley Wells Kemp was born on 14 June 1882, the second of three sons of Stephen Kemp, F.R.A.M., professor at the Royal Academy and Royal School of Music. Of his earlier years little of significance is recorded beyond a boyish interest in animals of all kinds and a story of an aquarium tank on an ambitious scale, secretly installed in an attic by the three brothers, which burst, with domestic results that impressed it on the memory of the constructors.

Nitrates in Aquarium Water

The formation of nitrate in the water of an aquarium tank stocked with fish was followed. As much as 1 gram per litre expressed as sodium nitrate was found.By adding lactate or tartrate to the water the development of denitrifying bacteria brought about almost complete removal of the nitrates and nitrites in the water.The experiments form part of an investigation made under the direction of Dr. Jan Smit.

The Preservation of Fishing Nets by Treatment with Copper Soaps and Other Substances

1. Under the conditions of the tests cotton and hemp nets became rotten in Aquarium tank water in two months or less in summer, in 4½–5½ months in winter.2. A mixed copper soap, containing oleate, stearate, and palmitate, is as good, probably rather better, than is copper oleate as a net preservative.3. “Cuprinol,” a petroleum acid copper soap, is better than the fatty acid soaps, both in fresh and in salt water. It is more than three times as expensive, however.