ALBERT

Notes: Abstract. Populations of postlarval, juvenile and adult Kuruma prawns, Penaeus japonicus Bate, have been affected by an unusual proliferative condition of the midgut and ventral nerve cord. Animals affected with this gut and nerve syndrome have been observed from various shrimp systems in Hawaii, including high density tanks and raceways, low density ponds, and adult broodstock held in a maturation system. Affected shrimp ranged in age from ∼20-day-old postlarvae of ∼0.02g average weight to adult shrimp of ∼ 60 g average weight. The principal lesions observed in affected animals were a hypertrophy of the anterior midgut mucosal epithelium basement membrane (BM) and a hyperplasia of the epineurium that covers the ventral nerve cord and segmental ganglia in the gnathothorax. There seemed to be a positive correlation between increased thickness of the BM and disease, and possibly a relationship between ataxia and lethargy and the degree of hyperplasia of the epineurium.

Notes: Abstract. Two groups of rainbow trout fingerlings were exposed for 90 days to 0.2 and 0.4 mg/1 of un-ionized ammonia, respectively. Several fish exposed to the higher concentration soon developed clinical signs suggestive of a neurological dysfunction but subsequently recovered. No lesion attributable to ammonia was seen in the gills of any of the fish. This raises questions about the precise role of ammonia in the production of gill diseases in intensively cultured trout.

Notes: Abstract. Proliferative kidney disease (PKD) was diagnosed in rainbow trout, Salmo gairdneri Richardson, at the Hagerman, Idaho, State Fish Hatchery. Wild fish from Riley Creek, one of the hatchery water supplies, were infected with PKD organisms. Clinical signs, gross pathology and histopathology of affected fish were typical of those reported for PKD in salmonids from European hatcheries. In addition to lesions normally seen, we observed a severe vasculitis and occlusion of renal and hepatic vessels. Ultrastructure of the PKD organism and possible inclusion body production sites are described. The disease outbreak was complicated by the presence of other infectious diseases. This is the first recorded outbreak of PKD in North America.

Notes: Abstract. The efficacy of the immersion method of vaccination was evaluated using Aeromonas salmonicida bacterin. In general a 2 min immersion vaccination was not as effective as vaccination by intraperitoneal injection; however, the level of immunity was improved by giving multiple vaccinations several days apart. A primary immersion vaccination with bacterin diluted 1:4 followed by a secondary vaccination diluted 1:2 gave good results. The most concentrated secondary booster was more effective than boosting with more dilute bacterin.

Notes: Abstract. Epitheliocystis infections in the gills of carp from Israel and Portugal occurred in lining epithelial cells as well as mucus and chloride cells. Ultrastructural studies of infected cells revealed several morphological forms of epitheliocystis showing the existence of a pleomorphic developmental cycle. The following stages were observed: chlamydia-like round cells (RC), non-dividing round cells (NRC) and bullet-shaped small cells (SC). All these were identical in shape to RC and SC described from epitheliocystis of other fish, The rickettsia-like cells (PLC and ILC) which occur in epitheliocystis from other fish species and produce the SC were absent in carp epitheliocystis and instead the RC were seen transforming into SC. Transformation to SC, however, occurred at any stage of the developmental process, even before the replication potential of the RC was exhausted, i.e. before reaching the NRC stage.

Notes: Abstract. Mebendazole (methyl-5-benzoyl benziraidazole-2-carhamate) was shown to have anthelmintic activity against larvae of Proteocephalus ambloplitis (Leidy) in implantations were found to be highly effective. A single intraperitoneal injection of 200 mg/kg or a capsule implantation of 200 mg/kg of mebendazole each reduced the infection by 95 % after 6 weeks. Oral treatment for 14 consecutive days at 100 mg/kg/ day reduced I he infection by 90%. Intraperitoneal injection of 200 mg/kg of mebendazole ever, did not interfere with spawning and reproduction of largemouth bass; however fish injected with 300 mg/kg produced no fry. Haematocrit, total haemoglobin, total serum protein and histological changes were not evidenl in treated fish.

Notes: Abstract. Rainbow trout fed prepared rations containing therapeutic levels of erythromycin (110 mg/kg daily) developed lesions in epithelial cells of the first proximal segment of the nephron. Pathological changes which developed within 24 h were characteristic of congestive overloading of lysosomes. Treated fish became anorexic within 2–3 weeks. Affected epithelial cells offish after 14 days of anorexia contained residual bodies in an otherwise normal appearing cytoplasm. Cell injury was reversible. Since the onset of anorexia corresponded with the completion of the recommended treatment period and damaged cells repair rapidly, erythromycin should nevertheless be retained as the treatment of choice for bacterial kidney disease.

Notes: Abstract. The activity of the pituitary-gonad axis was examined in goldfish, Carassius auratus (L.), collected from two populations exhibiting epizootics of an ulcerative disease. One population, collected from a pond in Toronto, Ontario, exhibited a significant linear relationship between the extent of lesions and the ovarian state. In a second population, collected from Hamilton Harbour, Lake Ontario, there was no correlation between the high prevalence of oocyte atresia, or the ovarian state with the extent of the ulcerative lesions. Additionally, in the Hamilton Harbour population there were no seasonal changes in the stages of egg development, frequency of mature ova, activity of the pituitary-gonad axis or gonadosomatic index consistent with gamete release. This apparent spawning failure of the Hamilton Harbour population was supported by the age distribution in the population (no fish younger than 4 years of age were found), and probably accounts for the drastic decline in the capture success of goldfish at that site since 1978. This decline in capture success was correlated with the outbreak of a persistent epizootic of ulcerative disease, suggesting that either the lesions themselves caused the spawning failure, or that the spawning failure and lesion outbreak were both correlated with undetermined changes in the environment, possibly a deterioration in the water quality in Hamilton Harbour.

Notes: Abstract. A spontaneous unilateral exophthalmos occurring in five species of otherwise healthy rockfish, Sebastes spp., was investigated. All eyes from nine unilaterally exophthalmic and seven non-exophthalmic rockfish were examined grossly and histologically. In all affected fish the exophthalmos was due to enlargement of the globes resulting from the formation of choroidal cysts filled with a clear, watery fluid and surrounded by dense, aberrant connective tissue. Cyst formation led to gross distortion and disorganization of the choroid. Distorted remnants of the choroidal rete mirabile contained markedly fewer erythrocytes, a homogeneous proteinaceous material and a mild inflammatory cell infiltrate. Thickened scleral cartilage with disoriented chondrocytes was also present in exophthalmic eyes. Some of the affected eyes showed pigmentary abnormalities with clumps of heavily pigmented cells present in the retina and choroid. Retinal degeneration and detachment was also evident in some of the affected eyes.

Notes: Abstract. The histopathology of an atypical Aeromonas salmonicida found in Atlantic cod, Gadus morhua L., is described. Unlike members of the Salmonidae, the cod showed a well-developed host reaction to A. salmonicida involving encystment of the bacteria. When Atlantic salmon, Salmo salar L., were given an intramuscular injection with suspensions of cultures of this strain of A. salmonicida no cellular host reaction was observed. When cod were given a similar injection the bacteria showed degenerative changes, leucocytes accumulated, and cyst formation was seen in the spleen and kidney. Since cod can be infected by this organism the possibility exists that they could act as carriers, a source of infection for salmonids in saltwater cage culture or in the wild.

Notes: Books reviewed in this article:Theory and Management of Tropical Fisheries. Ed. by D. Pauly & G. I. Murphy.

Notes: A new method of determining fish numbers in a large river, which involved electrofishing from boats downstream to an AC electrical barrier, produced capture efficiencies for different species ranging from 28 to 82% when successive pairs of catches were combined. Estimates of population density, biomass and production for the 18 species in a 2.538 ha segment of the Pilica River, Poland revealed a decline in total numbers of the fish in species diversity between 1963 and 1980. This is attributed to increased fishing pressure, and to a loss in habitat diversity following the loss of many water mills and associated dams. The total production estimate of 0.85 g m−2 year−1 is low compared with the few published estimates for other large rivers. Roach, dace, chub, gudgeon and bream were the most numerous fish and they constituted 75% of the total population estimate, and 68% of the standing crop and annual production.

Notes: Every year from 1939 to 1982 autumn-spawning charr, Salvelinus alpinus L., have been monitored in the north basin of Lake Windermere. Gillnets of mesh 32 mm bar were used. Up to 1974 the nets were set in Low Wray Bay, but, because of interference by the public, from 1975 they have been set at Thompson Holme, a less accessible site. The results from the two sites are not directly comparable. The main spawning time is November, and catch per unit effort (net day) in November has been calculated. From 1944 to 1974 the catch per unit effort showed an increasing trend, and from 1975 to 1982 it has been relatively stable. Growth was similar in the 1940s and 1970s. It is suggested that the increase in numbers of charr could be due to reduced predation by pike.

Notes: Densities of salmon, trout and grayling were assessed in Scottish streams by systematic counting by underwater observers, where the water was greater than 1 m deep, and by using electrofishing equipment in adjacent shallower areas. Tests of the efficiencies of the two methods are described. Applications have included the estimation of production of trout, grayling and young salmon at a site on the River Tay and predicting the salmon smolt run of the River Tilt, and these applications are briefly described. The most suitable period for visual counting was summer, as at water temperatures of less than 15° C fish were hiding among stones in the stream bed. Wet weather hampered both electrofishing and visual counting.

Notes: Large variations in the number of female adult salmon spawning in the Girnock Burn each year (range 28–127) produced smaller variations each year (range 2900–5600) in the number of juvenile migrants. The relative constancy of the parr migrations was achieved by changes in their age composition. There may be no advantage in allowing ova deposition to exceed a level around 200 000 (3.4 m−2) in the Girnock Burn, which would give rise to an average of about 4000 juvenile migrants (0.07 m−2) per season. Large numbers of ova (up to 12.5 m−2) did not decrease the number of juvenile migrants.

Notes: Landlocked salmon derived from a wild population of stunted ouananiche and bred in the laboratory showed signs of smoltification, but adaptation to sea water was slow and limited to 11% of the fish tested. Sea water survival was not related to initial size, within the range used, nor to sex, age (2 + years v. 3 + years) or spawning history.Freshwater ouananiche had fewer gill chloride cells than anadromous smolts of similar size in fresh water. Anadromous smolts showed an increase in chloride cells after adaptation to sea water and those ouananiche which successfully adapted to sea water had a greatly increased number of gill chloride cells.

Notes: Fish mortalities in the River Nidelva, South Norway in 1978, were suspected to be caused by Gas Bubble Disease. In June 1980, the hydrological situation occumng in the Nidelva in 1978 was reconstructed, and the effects were analysed by keeping fish in cages. Examination of the dead fish showed that most were killed by Gas Bubble Disease. The results also showed that brown trout, Salmo trutta, was the least tolerant, and eel, Anguilla anguih, was the most tolerant to dissolved gas supersaturation. Only fish kept near the surface were killed while fish kept at 3 m depth were mildly affected due to hydrostatic pressure compensation. In contrast to the situation in 1978, few of the wild fish were killed during the experiment in 1980.

Notes: Cichlasoma nigrofasciatum, the convict cichlid, is a biparental, substrate-spawning, Central American cichlid. Male-female pairs were kept for 4 months on one of three food rations: high–1 g food daily; medium–1 g three times per week; low–1 g per week. The number of spawnings was directly related to the food ration. The fecundity of the females on the low and medium rations declined. At all rations the inter-spawning interval and egg size increased during the experiment. Egg size was positively related to ration and the length of the inter-spawning interval, but the latter was inversely related to ration. Females on the high ration grew in weight while those on the low ration lost weight. Histological examination of the ovaries at the end of the experiment suggested that low rations reduced the proportion of oocytes that become vitellogenic. At the end of the experiment, the total, gonad and liver weight of females at a given length were significantly related to ration. No similar, significant effect was found for the males, although growth in length of the males was related to ration. Ration had no detectable effect on the histological appearance of the testes.

Notes: Fish were sampled by electrofishing at three contiguous sites 26 km from the source of Oued Sebaou, a seasonal river in North Algeria. River discharge ranges from 300 m3s−1 in the peak of the rainy season to 0.1 m3s−1 at the end of the dry season. Extensive gravel extraction from the river bed takes place during the dry season.Two species were recorded at each site: Barbus callensis, which is heavily fished locally, and Anguilla anguilla. The three sample maximum likelihood Zippin method was used to estimate mean density and standing crops, which were: barbel, 452 fish ha−1, 5.33 kg ha−1; eels, 149 fish ha−1, 3.04 kg ha−1. Estimated average biomass and production were: barbel, 2.31 kg ha−1, 4.27 kg ha−1 year−1; eels, 1.51 kg ha−1, 2.60 kg ha−1 year−1.

Notes: Changes in the size and composition of a population of the acanthocephalan Acanthocephalus clavula in eels, Anguilla anguilla, and flounders, Platichthys flesus, its definitive hosts, in a small river are described over a period of 4.5 years in the course of which the population underwent a steady and continuous decline. Parasite prevalence and abundance declined more rapidly initially and then more gradually, and during the period the frequency distribution changed from overdispersed to being close to random on most occasions. Throughout the whole period newly recruited parasites were found in eels, and adult females continued to mature and produce acanthors. Data on the distribution and occurrence of the intermediate host Asellus meridianus in the river suggested that in the latter part of the decline it was no longer possible for the parasite to complete its life cycle in some parts of the river, and the cause of the parasite population decline is believed to be the decrease in abundance of the intermediate host as a result of interspecific competition with a congeneric species. During this latter period, immigration of infected eels from another river in the catchment may have contributed to the maintenance of the parasites in the locality, but it is considered that the decline in the river was representative of what was happening in other parts of the catchment and that the whole parasite population in the catchment was declining for the same reason.

Notes: The effects of capture stress, exposure to a hypo-osmotic environment and elevated water temperatures on the ascorbic acid (AsA) content of several mullet, Mugil cephalus, tissues were examined. All the treatments significantly altered tissue AsA levels, but the pattern of AsA fluctuations varied. Gill AsA concentrations increased two fold after exposure to a hypo-osmotic medium (salinity changed from 30‰ to 5‰), whereas AsA content in this tissue declined after capture. Both treatments depleted AsA reserves in the kidney. AsA concentrations in the brain increased after exposure to low salinity and elevated water temperatures, but were unaffected by capture stress. None of the treatments caused long term alteration of hepatic AsA reserves. Ascorbic acid inhibited oubain-sensitive Na+, K+-ATPase activity of gill tissue in vitro. The results suggest an involvement of AsA in osmo- or ion-regulatory functions of teleosts gills, salinity and thermal adaptation mechanisms in neural tissue, and the response of renal tissue to adverse environmental stimuli.

Notes: Changes in the seasonal development of the gonads in Acanthopagrus latus and A. cuvieri over an annual reproductive cycle are described. There is one major spawning period from January to March. Hermaphrodite A. latus and A. cuvieri constituted 5.8% and 5.7% of the total sample respectively. The histological changes in the ovary, testis and ovo-testis in both species are described. Fecundity estimates for A. latus, 27.5–31.8 cm, ranged from 1 362 137 to 2 152 993, and estimates for A. cuvieri, 47.1–63.5 cm, ranged from 308 273 to 1 693 365.

Notes: Triploid rainbow trout were produced by hydrostatic pressure applied to eggs 40 min after fertilization. Treatment for 10 min with or without exposure to 2% ether produced high hatching rates. Nuclear measurements from serial section of 40-day-old fry and from blood smears of 5-month-old juveniles showed that the proportion of triploid individuals was 80–90%. Ether treatment alone did not induce triploidy. Attempts to produce tetraploids by hydrostatic pressure treatment of eggs at 8 h after fertilization failed. Parallel results were also obtained with heat shock.

Notes: The stages in the life cycle of Bothriocephalus acheilognathi have been studied with the aid of scanning electron microscopy. Emergence of the coracidium occurred after 3–5 days at 20°C. Soon after hatching the coracidium began to swell and the cilia became coiled and lost their locomotory function. The surface of the coracidium was covered in protuberances of unknown function. After consumption by the copepod intermediate host, the coracidium developed into a procercoid. Upon development of a cercomer the procercoid could infect the fish definitive host. Identification of adult B. acheilognathi should be made on specimens relaxed in cold water for 10 min, and be based on the heart shaped scolex and prominent square apical disc.

Notes: The numbers of chloride cells on the gills of three-spined sticklebacks, Gasterosteus aculeatus, have been measured after exposure of the fish to 0.5, 1.0 and 1.5 mg Cd2+ dm−3 soft water (132 mg dm−3 as CaCO3) and 2, 4 and 6 mg Cd2+ dm−3 hard water (299 mg dm−3). The numbers of chloride cells increased with time but later tended to decline. The significance of this finding is discussed in relation to the functions of chloride cells, one of which is presumed to be to eject absorbed heavy metals such as cadmium.

Notes: Book review in this article:FISH STOCK ASSESSMENT. A MANUAL OF BASIC METHODS, by J. A. Gulland.FROM YEAR TO YEAR: INTERANNUAL VARIABILITY OF ENVIRONMENT AND FISHERIES OF THE GULF OF ALASKA AND THE EASTERN BERING SEA. By Warren S. Wooster.

Notes: Scanning electron microscopy was used to examine the intestinal bulb and the caudal portion of the intestine proper of the goldfish, Carassius auratus. The observations made correlated well with previous light microscope studies by other investigators. The mucosal surface of the entire intestine of the goldfish is thrown up into folds, which are oriented along the long axis of the digestive tract in the intestinal bulb, but run more or less transversely in the caudal intestine. Tops of the folds were observed to be rounded or flattened, and the folds themselves formed wavy or zigzagging patterns in the mucosal surface. Numerous mucus-secreting goblet cells were seen, which were apparently more numerous or more active in the caudal intestine than in the intestinal bulb. The goblet cells are not uniformly distributed throughout the mucosa: they are more evident on the sides of the folds, although occasionally they appear to be located in clusters on the tips.The goblet cells were observed to contain varying amounts of mucous material, and/or to be of different sizes. Although no histochemical tests were performed, the possibility that digestive enzymes known to be present in the intestine may be elaborated by the goblet cells was considered, based on their variable appearance.

Notes: Crappie, Pomoxis annularis, from Lake Decatur, Illinois, were reported to have a high incidence of backbone deformities, an investigation was initiated to determine both the mechanism of vertebral injury and the causative agent. Three groups of fish were collected: normally shaped and abnormally shaped crappies from Lake Decatur and control fish from abnormally shaped crappies from Lake Decatur and control fish from nearby Lake Sangchris. Analysis of organic and inorganic residue levels in fish tissue revealed no significant levels of contaminants in any of the three groups. Evaluation of the mechanical properties, biochemical composition, and density characteristic of vertebral bone showed no significant difference between the three groups. A myxosporidean parasite, found in both normal and abnormally shaped crappies from Lake Decatur, may have been a contributing factor leading to the spinal deformities. We believe that a short-term exposure to organophosphate insecticides, may have occurred causing muscular contractions and resulting in vertebral damage and abnormally shaped fish.

Notes: The dynamics of increase of the predominant white muscle fibres of the myotomal bulk in bluntnose minnow, Pimephales notatus, ranging from 2.0 to 9.1 cm f.l. have been analysed by examination of modal progression of fibre diameter frequency classes in fish fed to satiation and growing at different rates at 15, 25 or 30°C. Recruitment of new fibres appeared to contribute little to increase in muscle bulk above 4 cm f.l., and nothing beyond 6 cm. The dominant means of increase was increase in fibre diameter. The limiting fibre diameter seemed to be 120 μ. These dynamics, which result in an approximately 1: 1 ratio between mean fibre diameter and f.l., are in contrast to those of the myotomal white muscle of rainbow trout, Salmo gairdneri, in which, regardless of differences in somatic growth produced by temperature, ration size or growth hormone administration, mean fibre diameter does not exceed that in bluntnose minnow until trout exceed 30 cm f.l. In trout there is, moreover, input of new fibres up to approximately 50 cm f.l., when subsequent growth, as in the minnow, is by means of fibre diameter increase. The bluntnose minnow is a small, slow growing species; the rainbow trout is a large, fast growing species. The discussion links these facts with the observed differences in fibre growth dynamics in relation to a hypothesis of interspecific differences in fish growth capability.

Notes: When plaice were injected intraperitoneally with either oyster glycogen or live Vibrio alginolyticus an acute cellular inflammatory response was observed. The duration of these responses, 7 and 15 days respectively, exceeded the time course of the mammalian cellular inflammatory reaction. Peak leucocyte numbers were found at 2–3 days and neutrophils, which were phagocytic, were more numerous than macrophages. Although the increase in macrophage numbers was less marked, these cells appeared more actively phagocytic than neutrophils. Cortisol injections and environmentally-induced stress caused a significant reduction in the extent of inflammatory cell infiltrates, while endotoxin significantly enhanced the response.

Notes: The structure of the mucous layer covering the oesophageal epithelium was analysed by scanning electron microscopy in the eel, Anguilla anguilla. Different fixation procedures were used to conserve the mucus in situ. The mucous layer changes progressively down the oesophagus from a thick dense layer to a very thin fibrous network. The possible roles of these mucous structures in ion absorption are discussed.

Notes: The apparent effects of environmental factors on skin structure in hatchery-reared brown trout are shown to be mediated by the influence of these factors on the skin parasite population. The presence of ectoparasites promotes a reduction in the concentration of epidermal mucus-secreting goblet cells, the magnitude of which is related to the intensity of infection.

Notes: Gravid sandsmelt, Atherina presbyter, were captured from Langstone Harbour, Hampshire, during 1978. They were maintained under laboratory conditions where spawning took place. The egg and its embryonic development are described. From fertilization to hatching took 26–27 days at 15°C and 13–15 days at 20° C. The newly hatched postlarvae were 6.5 to 7.2 mm long. Postlarvae 10.7, 13.4, 15.4 and 19.0 mm taken from the same locality are described and compared with previous descriptions. Their occurrence confirms successful spawning in the central English Channel.

Notes: Young of the year striped bass, Morone saxatilis, were exposed to sublethal concentrations of zinc and benzene and infected with larval Anisakis nematodes to determine the effects of these stressors on various physiological parameters. Results indicated that both pollutants and parasites significantly decreased haematocrit values. Parasites alone increased the liver somatic index, decreased haematocrits and, in the initial phase of the experiment, lowered antibody titres. Pollutants alone did not appear to significantly affect antibody titres, nor was there any difference in zinc and benzene uptake in the livers of infected and non-infected fish.

Notes: Ranges in the means of blood measurements from 121 Baltic salmon taken on nine occasions spread over an annual cycle were: packed cell volume or haematocrit; blood haemoglobin; red blood cell counts including immature erythrocytes; mean corpuscular haemoglobin concentration; mean cellular haemoglobin content and mean cellular volume. Seasonal changes appeared in all blood variables. Ontogenetic differences occurred in RBC and mean cellular volume when comparing 1 + parr with 2 + smolts in August one year apart, and in haemoglobin, RBC and immature RBC when comparing 1 + parr with adults once in November 1976. This points to greater influence upon haematological variation by season than by age. Significant regressions found within age groups, between pairs of mutually independent blood variables, are presented.

Notes: Book reviewed in this article:FISHERIES ECOLOGY, by T. J. Pitcher and P. J. B. Hart.PRINCIPLES AND MEASUREMENTS IN ENVIRONMENTAL BIOLOGY, by F. I. Woodward and J. E. Sheehy.OCEANOGRAPHY AND MARINE BIOLOGY: An Annual Review, Volume 21. Edited by Margaret Barnes.LIFE IN INLAND WATERS, by W. D. Williams.

Notes: Rg and Ch typing was performed, by serum inhibition, on 145 families that had been typed for HLA/C4/BF/C2 with a view to assessing partial inhibition (p.i.) of anti-Rg/Ch and its haplotype associations. Rg p.i. was found predominatly with the C4A*3A*,2,B*QO homoduplicated C4 haplotype and BFF. The original type of Ch p.i. (Nordhagen et al., 1980) was closely associated with the allotype C4B 2, which also occasionally exhibited complete inhibition (c.i.), but this Ch p.i. was also found with the C4A*1,B*QO haplotype (Rittner et al., 1984a). The second type of Ch p.i. (Giles, 1984) was closely associated with the C4B 1 allotype most frequently in the haplotype C4A*6,B*1 but also with C4A*3,B*1. Both types of Ch p.i. are usually found with BF S. The present data indicate that the determinants of Rg and Ch are not directly related to any particular C4 allotype or extended haplotype.Further examples of C4A 1 with Ch and C4B 5 without Ch determinants have been detected and theoretical considerations are discussed as to how they might have arisen from unequal crossovers in homologous regions that result in hybrid protein molecules.

Notes: A comprehensive strategy for the systematic localization of all continuous antigenic sites within a protein has previously been introduced by this laboratory. The strategy consists of studying the immunochemical activity of a series of consecutive synthetic peptides that encompass the entire protein chain and the are uniform in size and in overlap at their N and C-terminals with neighbouring peptided. By application of this strategy to sperm whale myoglobin, we have been able to delineate the ontinuous sites of T cell recognition of myoglobin in three high responder mouse strains. Thirteen 17-residue peptides that encompass the entire myoglobin chain and overlap by five residues at both ends were synthesized, purified and characterized. The peptides were examined in vitro for their ability to stimulate lymph node cells from myoglobin-primed DBA/2 (H-2d), BALB/c (H-2d) and SJL (H-2s) mice as well as long-term cultures of myoglobin-specific T cells. Several regions of the moleculr (T sites) were founnd to stimulate myoglobin-primed lymph node cells and myoglobin-specific long-term T cell cultures. This strategy has enabled the localization of the full profile of dominant sites of T cell recognition in myoglobin for these mouse strains. Of these T sites, one region, residues 107-125, was clearly immunodominant in these strains and was found to coincide with the antigenic (i.e. antibody binding) site 4 of myoglobin. Also, other regions stimulated T cells and appeared to coincide with previously known antigenic sites. It is noteworthy that, in addition to sites recognized by both T and B cells, the protein has other sites which are recognized exclusively by T cells and to which no detectable antibody response is directed.

Notes: Spleen cells from Balb/c mice given multiple injections of intact human erythrocytes (group O, NN) were fused with NS1 myeloma cells. Culture fluids from the resulting hybrid cells were screened for agglutinating antibody against a panel of erythrocytes. One cell line, 2/23, secreted an IgM antibody which reacted more strongly with NN than with MM cells. Neuraminidase or papain treatment of erythrocytes abolished agglutination whereas trypsin treatment did not. Reactions with U-erythrocytes of different MN phenotypes confirmed the anti-N specificity of monoclonal antibody 2/23. This is the first report of monoclonal anti-N stimulated by the immunization of mice with intact erythrocytes.

Notes: Spleen cells from 30 individual murine irradiation chimeras of the type (P1 x P2)F1→ P1 were compared in a rosetting assay for H-2K and H-2D cell surface antigen expression with normal (P1 x P2)F1 hybrid controls. Eleven out of the 30 chimeras were in the normal range, but the other 19 differed from F1 controls by 4- to 100-fold in endpoint titre for at least one H-2K or H-2D antigen. Every possible class of variation was found, i.e. up or down variation of H-2K or H-2D antigens of P1 or P2 type. This evidence, together with data from T6 chromosome marker experiments which also showed full reconstitution of lethally irradiated P1 recipients by (P1 x P2)F1 donor lymphomyloid stem cells, suggested that incomplete reconstitution was not the cause of H-2 antigenic variation.Low expression of P2 H-2 antigens on spleen cells derived from (P1 x P2)F1→ P1 chimeras was investigated further. Fifteen lethally irradiated (P1 x P2)F1 recipients of bone marrow cells from two such chimeras were all of normal F1 H-2 phenotype when tested 10-12 weeks after reconstitution, thus excluding stable, low P2 H-2-expressing variant F1 stem cells as a cause of the phenomenon. If P1 recipients were hyperimmunized against P2 cells before lethal irradiation and reconstitution with (P1 x P2)F1 stem cells, there were significantly fewer Till-McCulloch colonies in their spleens 10 days after reconstitution than in spleens of unimmunized controls. Also 〉 90% of immunized recients died by 6 weeks after stem cell injection but two survivors both showed very low levels of P2 H-2K and H-2D antigens. These results together with previously published evidence of anti-P2 Tc cell activity and P2 skin graft rejection in (P1 x P2)F1→ P1 chimeras suggested that residual anti-P2 immunological capability in lethally irradiated P1 recipients may be associated with low P2 H-2 expression on their F1-derived spleen cells, although the mechanism does not involve selection of stable, variant F1 stem cells. The mechanism(s) of other classes of variation in H-2 expression in (P1 x P2)F1→ P1 chimeras were not investigated.

Notes: RNA was extracted from the splenocytes of Brucella abortus antigen stimulated mice and of control mice. The proportion of chromatographically separated polyadenylated 11.2S mRNA, was determined. With the technique used, only stimulated mice exhibited significant amounts of this RNA species. The highest level was reached 1 day after the stimulation, and the decay from this level presented an oscillatory form during the 4 weeks following the injection.In two different genetic backgrounds, H-2b mice did not respond to the stimulus, in contrast to H-2a and H-2f mice. H-2b/H-2f heterozygotes behaved roughly as intermediate between H-2b and H-2f mice. This genetic control seems to parallel the genetic control of some Brucella-induced, thymus-dependent events previously described.

Notes: Book Reviews in this ArticleR. WITKOWSKI and O. PROKOP: Genetik erblicher Syndrome und Mgbildungen. Worterbuch fur die Familienberatung.

Notes: Monoclonal anti-Ia inhibition experiments were conducted to confirm and extend genetic mapping data of I-A gene control of immunity to human haemoglobin (Hb). It was found that the Aβ gene is of critical importance in conferring immunity to the α-chain and β-chain subunits of Hb. A possible involvement of I-E region genes in B10.D2 mice to β-chain is discussed. Through the use of an α-chain specific T cell clone data, is obtained indicating that an intact Ia.8+ Aβ chain is necessary for antigen presentation in vitro.

Notes: SUMMARY. 1. Measurements of oxygen, pH, phosphate, nitrate, nitrite, hydroxylamine. ammonium and sulphide were made in four Ethiopian crater lakes during 1964, 1965 and 1966 at fairly regular intervals. The seasonal pattern of the dynamics of these chemical constituents is described for depth and time and relates closely to the pattern of thermal stratification and mixing previously described.2. Interactions between the chemical constituents are examined and comparisons are made between the four lakes which differ widely in their depth, exposure to wind and standing crops of phytoplankton.3. The vertical distribution of the chemical constituents is used to help define the limits of circulation of surface waters and the need to understand the seasonality of chemical stratification in relating climatic, morphometric and biological events, especially in tropical lakes, is stressed.

Notes: SUMMARY. 1. Natural population sinking rates were calculated by fitting an exponential regression to 6 years’observations on declining crops of Melosira italica subarctica O. Müll. and Stephanodiscus astraea (Ehr.) Grun.2. Losses were described by an exponential model which yielded still water sinking rates of 0.86 md−1 for M. italica and 0.45md−1 for S. astraea.3. Laboratory measurements of the sinking rate of natural populations showed that the rate increased abruptly from less than 0.2 m d−1 in growing populations to 0.4 m d−1 after silica depletion.4. The measured sinking rate of S. astraea agreed well with that observed in the field. Where as populations of M. italica appeared to sink more quickly in the lake than could be accounted for by laboratory observations.

Notes: Book reviewed in this article: Carmouze, J.P., Durand, J.R. & Leveque, C. (1983) Lake Chad. Monographiea Biologicae Saether, O. A. (1980) Glossary of Chironomid Morphology Terminology (Diptera: Chironomidae). Ashe, P. (1983) A Catalogue of Chironomid Genera and Subgenera of the World including Synonyms (Diptera: Chironomidae). Wiederholm, T. (Ed.) (1983) Chironomidae of the Holarctic Region. Keys and Diagnoses. Part L Larvae. Saether, O.A. & Sublette, J.E. (1983) A Review of the Genera Diothrix n.gen., Georthocladius Strenzke, Parachaetocladius Wülker and Pseudorthocladius Goetghebuer (Diptera: Chironomidae, Orthocladiinae).

Notes: SUMMARY. 1. Invertebrates associated with four species of aquatic plants and on the adjacent substrate were investigated in a riffle/run section of a hard-water stream.2. Invertebrates were more numerous on stones than on any species of plant (〉 17,000m−2 versus 1000–4000 m−2). Gatherers were more abundant on Ranunculus longirostris, where proportionally more fine detritus was trapped in the leaf bundles than on other plants. Scrapers were most numerous on Charu vulgaris, where attached diatoms were also most prevalent.3. Invertebrate community structure on three plant speeies was quite different from that on stones. This was not the case for Potamogeton amplifolius which appeared to be used by the organisms as a mere extension of the substrate.

Notes: SUMMARY. 1. Dissolved organic matter (DOM) was measured at 8h intervals over a 1 year period in a stream draining 51 ha of moorland with peaty soils.2. DOM concentrations increased with increasing stream discharge from low flow values of 0–3 mg 1−1 to maximum values of 30 mg 1−1. There were also seasonal differences of up to 13mgl−1 between August (maximum) and February, and differences of about 2.5 mg l−1 between rising and falling stage samples.3. Seasonal variation was closely related to mean temperature.4. Total loss over the year was 168 kg ha−1 DOM (84 kg ha−1 C), larger than previous estimates for upland sites.

Notes: SUMMARY. 1. Monthly and diel patterns of food consumption by the three-spined stickleback, Gasterosteus aculeatus L., were studied in Llyn Frongoch, a small reservoir in upland mid-Wales.2. Copepods were particularly prominent in the diet in spring and autumn, with ephemeropteran nymphs prominent in summer. Chironomid pupae and stickleback eggs were also elements of the diet in summer, whereas algae, plant material and debris were more important in autumn and winter. Chironomid larvae and ostracods were present throughout the year, but there was some doubt as to the importance of ostracods as digestible food items.3. Stomach contents were heaviest in spring and late summer and lightest in late autumn and winter.4. Samples for the diel samples were taken four times, once in each season. These diel samples largely reflected the seasonal changes in diet noted in the monthly samples. There were few cases of a clear switch in the composition of the diet during a 24 h period. Feeding occurred during daylight, the weight of the stomach contents declined during darkness.3. Several methods provided estimates of the daily rate of food consumption which ranged from 3.5 mg in December (4°C), to 19.0 mg in May (15°C). These estimates and others obtained independently suggest that the annual rate of food consumption for a stickleback in Llyn Frongoch is between 2000 and 5000 mg wet weight.

Notes: SUMMARY. 1. The reliability of the simple frequency, Janetschek, Cassie and Dyar's law methods for determining or corroborating instars of mayflies and stoneflies was evaluated using data from published studies, a population of Baetisca rogersi and populations simulated through use of random numbers and generated normal distributions.2. The Janetschek and Cassie methods are variations of the simple frequency method that offer no significant advantage. Modes of the Cassie method, thought to represent instars, are much more difficult or impossible to detect than are the corresponding peaks of the other two methods.3. Overlap in size between adjacent instars can lead to false instar peaks or modes in frequency plots. The potential for overlap in mayflies and stoneflies is greatly increased, compared to other insects, because of their large number of instars and known developmental variability. The normal distribution simulations demonstrated that instar size variability as low as 5–7.5% COV (coefficient of variability) may lead to false instar peaks when the number of instars is in the typical range. These simulations also indicated that even simple frequency plots with distinct peaks may result in inaccurate instar determinations.4. The number of size classes used in an analysis was correlated with the number of peaks or modes revealed. The number of peaks greater than zero in the Janetschek plots for the Baetisca rogersi population varied from 5 to 53 as the number of size classes was varied from 20 to 188. Similarly for the random number simulations. the number of peaks varied from 6 to 41 as the number of size classes varied from 22 to 127.5. Dyar's law semi-logarithmic plots do not corroborate instars determined through frequency methods, because the uniform spacing of‘instar’data points is the direct result of the uniform spacing of peaks in frequency plots of most data sources (including random numbers), whether or not peaks actually indicate instars. Also Dyar's law plots will‘corroborate’different numbers of instars depending on the peak selection criteria used. The potential for corroborating instars through supplemental rearing and best-fit analysis is discussed.6. The future of mayfly—stonefly instar determination lies in the increased and more rigorous application of the rearing and Palmen body (mayflies only) methods.

Notes: SUMMARY. 1. Basic physical and morphometric data are presented for sixty-five lochs on the Shetland Islands. The interrelations between loch dimensions are comparable to those recorded elsewhere in Scotland, but the smaller lochs on Shetland tend to be somewhat shallower, and the large lochs somewhat deeper than usual.2. The results of a multivariate analysis show that most of the physical variables measured in the field are closely correlated with easily measured map attributes.

Notes: SUMMARY. 1. Between February and September 1974, concentrations of fulvic and humic acids in waters from a cryoboreal region of the Precambrian Shield in Quebec varied between 0.5–6.1 mg 1−1 and 0.1–6.5 mg 1−1 respectively. Whereas the fulvic acids usually remained relatively constant during this period, humic acids showed appreciable increases.2. The number and weight average molecular weights of the fulvic acids (∼5000 and ∼22,000 daltons respectively) were lower than those of the humic acids (∼20,000 and ∼75,000 daltons respectively). The average molecular weight of the aquatic humic matter often decreased during late summer and early autumn. During spring floods the molecular weight of fulvic acids increased and that of humic acids declined.3. Because the aquatic humic acids were more intensely coloured than fulvic acids, they contributed more than 30% of the colour of the water even though they accounted for only 15% of the concentration of humic matter. The colour intensity of both fulvic and humic acids generally appeared to increase during the latter part of the summer, when there was normally a decrease in the value of the colour quotient (E4/E6 ratio), indicating the accumulation in the waters of more humified material.

Notes: Book reviewe in this article: Schiemer, F. (Ed.) (1983) Limnology of Parakrama Samudra, Sri Lanka. Developments in Hydrobiology.

Notes: SUMMARY. 1. The waters of Opi Lake were very dilute (15–24 μS cm−1at 25°C) and somewhat acid (pH 6.0–6.5), probably a result of the highly leached lateritic soils in its small drainage basin.2. Annual minimum water temperatures were recorded during the early dry season, not during the rainy season as has been observed in most other West African water bodies. This was attributed to the influence of the Harmattan winds on the lake and the absence of pronounced rainy season flooding, as might occur in reservoirs.3. A diel cycle of daytime thermal stratification and complete or near-complete night-time destratification occurred throughout the year.4. During the dry season, when prevailing winds were strong and lake depth shallow, night-time destratification was accompanied by deep circulation. In the rainy season, when prevailing winds were weak and lake depth was greatest, deep vertical circulation apparently did not take place, as evidenced by anoxia in near-bottom waters. This is the reverse of the pattern seen in many tropical lakes.

Notes: SUMMARY. 1. Spine development in a clone of unspined Keratella cochlearis was promoted by a water soluble factor released by the copepods Tropocyclops prasinus and Mesocyclops edax and by the predatory rotifer Asplanchna priodonta. Between 9 and 55% of K. cochlearis populations cultured in predator-conditioned media responded to the inducing chemical.2. The K. cochlearis form possessing a posterior spine of medium length was much less susceptible to predation by small Tropocylops and Asplanchna than the form lacking the posterior spine. These predators consistently selected the unspined form over the spined form when offered equal densities of each. However, both spined and unspined forms were equally susceptible to predation by large Mesocyclops.3. The phenotypic variation of offspring produced from induced unspined Keratella females encompassed much of the variation reported for the taxon in North America. These morphotypes are similar to the variation of forms reported for the K. cochlearis tecta series known from Europe. We suggest that the North American morphotypes be identified in studies of this species because the presence of the posterior spine can greatly affect predator selectivity.

Notes: SUMMARY. I. Movement of 33P from hypolimnion to epilimnion in a small, dystrophic lake was investigated using small-diameter experimental tubes enclosing thermally stratified water columns. This approach was made possible by the extremely sharp stratification found in such lakes, in which the euphotic zone closely coincides with the epilimnion.2. The vertical distribution of inorganic phosphorus in the lake showed a sharp increase across the thermocline so that enhanced concentrations were available to phytoplankton just below the thermocline. Inorganic nitrogen concentrations did not show such a marked relation to thermal stratification.3. One abundant motile alga (Cryptomonas marssonii) showed striking and regular vertical migrations in the lake, moving below the thermocline at night and returning to the surface waters in early morning. These migrations took cells across a 10°C temperature gradient. Non-motile phytoplankton showed constant vertical distributions.4. In the experimental tubes an upward movement of phosphorus took place from hypolimnion to epilimnion which was only attributable to transport by phytoplankton cells undertaking active vertical migrations. No equivalent movement of phosphorus occurred in control tubes from which algae were absent.5. The possible significance of such nutrient retrieval is discussed with reference to plankton phosphorus budgets and competition between phytoplankton species.

Notes: SUMMARY. 1. Macro-invertebrate species lists were obtained for 268 sites on forty-one river systems throughout Great Britain by qualitative sampling in spring, summer and autumn. Information on twenty-eight environmental variables was also collated for each site. The sites were ordinated on the basis of their species content using detrended correspondence analysis (DCA) and classified by two-way indicator species analysis (TWINSPAN). Correlation coefficients between ordination scores and single environmental variables indicated that Axis 1 distinguished between types of rivers and Axis 2 reflected variation along the length of rivers. A preliminary classification of sites into sixteen groups has been proposed, together with a key which allows new sites to be classified. Information on the species and environmental features which characterize each group is also presented.2. Multiple discriminant analysis (MDA) was employed to predict the group membership of the 268 sites using the twenty-eight environmental variables. 76.1% of sites were classified correctly. An independent assessment of predictive ability using forty test sites yielded a 50% success rate. Predictive ability was higher for the classification presented in this paper than in fifteen additional classifications produced using data from single seasons and/or different taxonomic treatments.3. TWINSPAN and MDA were found to be useful approaches to the classification of running-water sites by their macro-invertebrate fauna and the prediction of community type (as indicated by the occurrence of species in the sites comprising the group) using environmental variables. Extension of the scope of the classification, coupled with the use of additional environmental variables to increase predictive ability, is now in progress.

Notes: SUMMARY. 1. Macro-invertebrate samples were collected from 268 running-water sites in Great Britain in each of three seasons (spring, summer and autumn). A combined seasons’treatment was generated by amalgamating the individual seasons’data. These four seasonal options were each subjected to four distinct taxonomic analyses differing in level of identification and whether the data were quantitative or qualitative. Thus sixteen data-sets were available for analysis. Environmental data on physical and chemical variables, macrophyte cover and date of sampling were also recorded for each site.2. All sixteen data-sets were ordinated by detrended correspondence analysis and classified by two-way indicator species analysis. There were strong correlations between the sixteen ordinations and significant concordance between classifications.3. The relationships between ordination scores and single environmental variables were investigated. Muhiple discriminant analysis was used to fit environmental data to eight selected classifications covering the full range of seasonal and taxonomic treatments. The environmental variables most useful in distinguishing between rivers were substratum characteristics, alkalinity and total oxidized nitrogen. Within-river differences were often highly correlated with discharge, distance from source, width and depth. Slope and altitude contributed strongly to both between-river and within-river distinctions.4. Between-site variation (beta diversity), eigenvalues of ordination, the reliability of classifications, the proportion of sites correctly assigned to their biological group using environmental data and the standardized similarity between observed and predicted fauna were all higher when identifications were taken to species level, rather than one of three family treatments. Qualitative data on a reduced list of families gave comparable or better results than more detailed family treatments.5. Combined seasons’data enabled better categorization and prediction than single season's.6. The values of the Czekanowski Index of Similarity between the observed and predicted fauna of test sites were close to realistic maximum values.7. Recommendations are made concerning potential usages of the various classifications. The species level classification has uses in the field of conservation and in the prediction of biological response to environmental change. The family level classifications have value in developing local site inventories and in the interpretation of pollution surveillance programmes.

Notes: SUMMARY. 1. Cephalodella for ficula (Ploima, Rotifera) lives in tubes it constructs itself. These tubes are built of mueus in detritus-rich environments. The tubes are often closed at both ends, arc not used as sieves, and are not eaten directly.2. The rotifer swims back and forth in its tube and apparently lives on bacteria which are shed from the inner walls of the tubes. Because of surface-to-volume considerations, this feeding strategy is probably only possible for animals smaller than roughly 1 mm. Under low food conditions, rotifers inside a tube have a distinctly higher fitness than rotifers removed from their tube.3. Given high food conditions, rotifers removed from a tube immediately build another. Grazing on particles outside the tube appears to take place when a tube is being lengthened. Rotifers do not leave the tube for routine feeding, but under conditions of starvation or very low oxygen concentration they will leave the tube and swim about.

Notes: SUMMARY. 1. The exceptionally dry summer of 1976 presented an opportunity to assess the impact of drought on the fauna of an unregulated stream in Wales.2. Total number of macroinvertebrates varied from 1808 m−2 in September 1976 to 7412m−2 in August 1977. Two main effects of drought were observed: an initial reduction in abundance during the drought and a change in community structure in the following year, probably through impaired reproduction.3. Trout density ranged from 0.075±0.028 to 0.402±0.093 m−2 and salmon parr density varied between 0.014±0.004 and 0.414±0.119 m−2. The only detrimental effect of the drought on the fish fauna was the elimination of the 1976 year class of young salmon. probably due to prolonged high water temperature.

Notes: SUMMARY. 1. The cocoon of Nais variabilis is ovoid with an average length of 527.6±8.4 μm (95% CL) and an average breadth of 378.1±9.9 μm. The cocoon wall is about 7 μm thick and the average volume of the cocoon cavity is 0.035±0.002 mm3. Most cocoons contain one ovum; only single-ovum cocoons developed.2. Cocoons hatch in about 80 days at room temperature (average 20°C. range 17–23°C). Hatchlings emerged posterior end first and were, on hatching, about one-third the adult live length of 8.5±10.3 mm.3. It is estimated that adult Nais variabilis are unlikely to produce more than an average of ten cocoons each. Adults ceased asexual budding on becoming nature and died shortly after the completion of cocoon production. There was a brief co-existence of generations.

Notes: SUMMARY. 1. Perforated boxes containing live, dead or no eggs of the rainbow trout, Salmo gairdneri Richardson, were buried in a natural spawning redd in a stream in North Wales for the duration of the natural incubation period.2. A significant difference (P〈0.001) was found between the mean number of invertebrates colonizing perforated boxes containing live eggs, dead eggs and no eggs.3. The number of eggs retrieved from boxes originally containing dead eggs decreased as the number of invertebrates colonizing the boxes increased.4. Using a serological method of prey identification it was demonstrated that Leuctra hippopus (Kempny), Gammarus pulex (L.) and Ptychopter-idae sp. scavenged on trout eggs in the field.5. There was some evidence that Rhyacophila dorsalis (Curtis) and Diura bicaudata (L.) preyed on trout eggs, but in view of their scarcity, it is suggested that they were a minor mortality factor.

Notes: SUMMARY. (1) A study was made of the biology of Chrysichthys auratus, a bottom-feeding omnivore, in Tiga Lake, a man-made lake in Northern Nigeria.(2) Ripe females were present from April to September, coinciding with the hot season and rise in water level. First spawning took place at age II in females. No ripe males were found, and this was attributed to their spatial separation. Absolute fecundity was related to length and ranged from 327 to 1466 in forty-six females.(3) Hyaline rings on the centra of lumbar vertebrae were counted to age 235 fish. The first ring is laid down at the end of the second year, after which the rings were formed annually, probably during the breeding season. The fish live for up to 6 years. There is a good fit of the growth curve to the von Bertalanffy equation. Growth is slow and a smaller maximum size is attained than in rivers.

Notes: SUMMARY. Larval Chironomus decorus (Diptera: Chironomidae), taken from experimental ponds to which a coal liquid had been added, were found to have deformities of the mentum. Aberrations of the medial portion of the mentum were significantly dose-related. Occurrence of such deformities appeared to be a less sensitive measure of pollution by the coal liquid than did previously reported changes in abundance, biomass, number of taxa, and species diversity of benthic insects.

Notes: SUMMARY. 1. Differences in food quality of suspended and benthic organic detritus, as measured by ATP content and C/N ratio, were assessed along three contrasting headwater streams in southern Ontario.2. Large differences in ATP content of sediments between cooler upstream reaches and warmer downstream reaches were detected. Sediment ATP content was highly correlated with stream temperature, presumably as a result of faster microbial growth, and with stream gradient. C/N ratios of sediments showed much the same pattern of differences as ATP, but were less variable.3. By contrast, the ATP content (or BIOC/POM ratio) and C/N ratios of suspended organic matter showed no systematic variation between upstream and downstream or between warmer open and cooler shaded areas, probably due to the very short residence time of suspended particles.

Notes: SUMMARY. 1. Male Gammarus pulex (L.) are typically twice as heavy as females in field caught pre-copula pairs and mating is positively size assortative. Earlier work had shown that relatively large males can swim in pre-copula at higher current speeds than males that are relatively small compared with their mates. We describe experiments on pair formation in the laboratory, in static water and in an artificial stream.2. Pairs formed in the artificial stream had a significantly higher weight ratio than either those formed in static water or those caught in the field. In both experimental conditions, males in pairs were significantly larger than singles. In the stream, the weight ratio of pairs increased with formation sequence due to a significant decrease in the size of selected females.3. It is concluded that these results are consistent with the hypothesis that the relatively large size of paired male G. pulex is a product of mechanical constraints rather than male–male competition.

Notes: SUMMARY. (1) The average benthic density of Peltoperla maria in an undisturbed southern Appalachian stream was more than twice that of a nearby stream draining a previously clear-cul catchment in its tenth year of natural secondary succession.(2) Peltoperla production estimates, using three methods, do not show a significant difference in production between streams draining the two catchments. We attribute these results to quicker growth and slightly higher densities of larger nymphs in the disturbed stream. Production estimates for the disturbed stream ranged from 498 to 560 mg (ash free dry weight) m−2y−1 while those for the undisturbed stream were 41–4–515 mg m−2 y−1.(3) Our results reinforce the view that conclusions based solely upon numerical densities may lead to erroneus interpretations about the roles organisms play in ecosystems.(4) Annual frass production by this shredder is about 20 times (10 g m−2 y−1) the secondary production of P. maria.

Notes: SUMMARY. 1. Of the various approaches to studying species-abundance patterns in aquatic ecosystems (particularly streams) the logseries distribution is the most appropriate. The distribution parameter, α, is readily estimated and goodness-of-fit of the model to the data can be estimated.2. A method exists which uses a to calculate an index of similarity from which cluster dendrograms can be constructed and the clusters tested for significant differences. Assumptions and calculations are presented.3. Procedures are illustrated, with examples from Idaho streams, and approaches to interpreting the results are included.4. Studies of stream macro invertebrates can fulfill the assumptions of the logseries distribution but cannot meet those of commonly used diversity indices.

Notes: SUMMARY. 1. Variations in the haemoglobin index of two neighbouring populations of Daphnia magna were recorded over a range of dissolved oxygen concentrations (0.5–4.0ml O2 1−1, 20°C). Reciprocal transfer experiments between habitats compared haemoglobin synthesis in situ.2. An inverse relationship was found between the oxygen content of pond water and the haemoglobin indices of laboratory and natural populations.3. Significant genetic differences in the synthesis of haemoglobin were found between the two populations. Animals from the poorly oxygenated habitat (0.8±0.18ml O2 1−1) had consistently higher haemoglobin contents (maximum HI, 87.7±4.5) at all experimental and in situ oxygen levels. D. magna from the well oxygenated pond (4.3±0.59 ml O21−1) had a lowered physiological ability to synthesize haemoglobin (maximum HI, 48.3±4.2). The process of ecological differentiation in Daphnia populations is discussed.

Notes: SUMMARY. 1. An examination has been made of the water quality of a 50 km (Wigan to Litherland) length of the Leeds-Liverpool canal. Regular in situ measurements accompanied by sampling for laboratory analysis were made at seventeen stations over a 15-month period.2. Three principal contributory water types have been recognized, and the observations have allowed estimates to be made of their relative contributions to the total water flux in the lower reaches of the system. Linear flow rates (c. 0.6 km day−1 near Litherland) are consistent with previous reports.3. The combined field and laboratory measurements have been used to obtain estimates of the partial pressure of CO2 in the water (P co2), the degree of saturation of the water with respect to calcite (Ω) and the major ion speciation in the water. Because of the variable ionic compositions of the waters examined, these estimates were made using a program (WATEQ) which took account of ion-pairing.4. Diurnal and annual cycles with respect to pH, P co2 and ω occur, these being most marked in the lower parts of the study length when, for a large proportion of the spring and summer, P co2 was below the atmospheric level and noticeable supersaturation with respect to calcite occurred. In contrast, two of the contributory water types, the River Douglas input and the Creek, showed low pH and Ω values and high P co2 values throughout the year.

Notes: SUMMARY. 1. In a laboratory experiment, larvae of Simulium noelleri were fed on polystyrene latex microspheres of a range of diameters from 5 to 100 μm.2. Examination of the particle size distribution in the water used in the experiment showed those 〈13μm to be the most numerous (87% of all particles present). Particles of this size made up 57±2% (mean ±SE)of the total of those in the gut of larvae.3. Comparison of particle composition in the gut contents and the water of the experiment, using Jacob's index of electivity, showed that larvae of all sizes filtered proportionally fewer of the particles 〈13 μm and more of those 〉13μm.4. As larvae increased in size they became better able to filter the largest particles present (〉52μm in diameter) and less well able to filter the smallest particles (〈13μm in diameter).5. Gut retention time was longer in larger larvae.6. The biology of S. noelleri, which inhabits lake outlets in high population densities, is considered in the light of these findings.

Notes: SUMMARY. 1. Rotenone was applied to Round Lake in the autumn of 1980 in order to eliminate predominantly planktivorous and benthivorous fish. The lake was subsequently restocked with a higher population density of piscivores. The effect of this biomanipulation on the phytoplankton and zooplankton communities and on total nutrient concentrations was monitored at fortnightly intervals during the summers, from May 1980 to September 1982.2. The abundance of phytoplankton was much lower after biomanipulation and was consistent with observed changes in Secchi disc transparency, total attenuation coefficient and chlorophyll a concentration. Zooplankters were also less abundant in 1981 and 1982 but the decrease in numbers was more than offset by the large increase in the mean sizes of the zooplankters present, so that the estimated grazing pressures in 1981 and 1982 were at least double the 1980 value.3. Daphnia, rare in 1980, became the dominant genus in 1981 and 1982, and a shift to progressively larger-bodied Daphnia species was observed.4. Although total nitrogen and total phosphorus levels were generally lower after biomanipulation, their decline could not explain the reduction in phytoplankton abundance which was attributed to the increased grazing pressure. Possible causes of the observed declines in nutrient concentrations are discussed.

Notes: SUMMARY. 1. A simple and inexpensive assay was developed to determine the amount of biologically available phosphorus (BAP) present in freshwater.2. BAP was measured by using Aeromonas hydrophila in a proteolytic assay system in which the release of the chromogen from an insoluble azure dye derivative of hide powder (HPA) was determined spectrophotometrically. The time necessary to hydrolyse 50% of the HPA was found to be directly dependent on the amount of BAP present. BAP within the range 2–250 μg 1−1 phosphate-phosphorus was detected.3. Our data suggest that the application of this assay for the measurement of BAP in freshwater offers the potential of monitoring the biological response of a freshwater ecosystem to phosphorus.

Notes: SUMMARY. 1. Diel depth distribution patterns of Ceratium hirundinella were studied during eleven sampling periods, covering the seasonal growth cycle. They were shown to result from short-term periodic or non-periodic external factors, endogenous responses of the alga, and interactions between these.2. Diel variations in wind stress resulted in the net transport of algae into or out of the sampling position due to lateral water movements. A progressive surface accumulation of Ceratium, leading to a 3-fold increase in cell numbers at the sampling site over a 24 h period, was due to wind-induced upwelling of deeper cells. Near-surface accumulation of Ceratium on a completely overcast afternoon, similar to that associated with migrations, was attributable to advection.3. Under sufficiently calm conditions, depth-differentiation of Ceratium was regulated by its vertical swimming movements with a diel periodicity. Migration patterns observed in earlier work were confirmed and extended. The alga migrated towards the surface during the daytime and downward during the night; this rhythm had an endogenous component.4. At high surface illumination, the alga retreated from the surface and formed discrete sub-surface maxima; at low irradiance Ceratium showed positive phototaxis and concentrated near the surface. Under either condition of irradiance Ceratium actively aggregated at depths associated with irradiance levels of about 125–155 μEinsteins m −2 s −1. Downward movement was restricted by anoxic conditions and possibly by thermal/ density gradients. However, given sufficient light penetration, dissolved oxygen and nutrient availability, the thermal density gradient does not apparently eliminate downward movement by Ceratium.

Notes: Book reviewed in this article: Fay, P. (1983) The Blue-Greens. Petr, T. (Ed.) (1983) The Purari—Tropical Environment of a High Rainfall River Basin. Nisbet, B. (1984) Nutrition and Feeding in Protozoa. Frank, J.H. & Lounibos, L.P. (Eds.) (1983) Phytotelmata: Terrestrial Plants as Hosts for Aquatic Insect Communities. Elliott, J.M. & Humpesch, U.H. (1983) A Key to the Adults of the British Ephemeroptera.

Notes: SUMMARY. 1. The results of a survey of thirty-four stream sites, differing in pH and invertebrate species richness, indicated that the pool of locally available, suitably adapted species was smaller in the acid streams. This plays a part in determining the general pattern of lower species richness at more acid sites.2. Diversity of feeding categories increased with species richness, indicating that a greater range of food resources was available in the less acid, more species-rich communities.3. The pattern of predation varied with pH and species richness. The numbers of large insect predators were lower in the less acid, more species-rich communities and this was correlated with the presence of fish.4. A detailed study of the guild of detritivorous stoneflies in four streams differing in species richness provided evidence that density compensation occurs, niche width decreases and niche overlap declines as species richness increases.5. We discuss the roles that competition and predation play in determining the structure and richness of stream invertebrate communities.

Notes: SUMMARY. 1. In daylight conditions brown trout preferably attacked head capsules with a contrasting colour pattern compared to those which were more uniformly coloured. This preference was reversed under reduced illumination. It is argued that striped head capsules are cryptic to predators at low light intensities.2. In caddis larvae contrasting head patterns are found mainly in lentic species, whilst the heads of lotic larvae are usually more uniformly coloured. Lentic species dwell in conditions of more diffuse illumination than lotic one, and each category thus achieves high crypsis with respect to head capsule coloration.3. Lentic molannid and phryganeid larvae often dwell at considerable depths, and these species also have the most sharply defined head patterns. These species are predatory and, besides being cryptic to larger predators, may also be cryptic to their prey.4. Intraspecific variation in head capsule coloration in relation to habitat type is also discussed.

Notes: SUMMARY. 1. Ceilulolytic decomposition, measured by loss of tensile strength in strips of cellulose test cloth, was estimated in thirty-four stream sites in experiments in summer, autumn and winter.2. The results of multiple regression analyses showed that strength loss was most closely related to temperature in summer, when the model accounted for only 38% of the variation, and to stream pH in autumn and winter, when the models accounted for 52% and 75% of the variation, respectively.3. The relationship between decomposition rate and the structure of invertebrate communities in streams of dissimilar pH is discussed. We argue that a very rapid rate of decomposition of coarse particulate organic matter may profit consumers of fine particulate organic matter at the expense of coarse particle shredders.

Notes: SUMMARY. 1. Phosphorus and nitrogen concentration in the surface sediment was analysed before, during and after fertilization of a small, stratified, subarctic lake. During stratification most (70%) of the added nutrients were deposited in the epilimnion sediment.2. After 2 years of fertilization there was a significant increase of both nutrients at all water depths, although values were 30–50% higher per square metre in the shallow areas.3. Nutrient budget calculations based on the sediment analyses showed that 75% of the added phosphorus and 45% of the nitrogen were accumulated in the sediment after fertilization.

Notes: SUMMARY. 1. Newly-laid eggs of Coenagrion puella (L.) from a pond near Herzogenburg (Lower Austria) were kept at constant water temperatures (range c.3.5°C to c.28°C)in the laboratory. Hatching success varied with temperature; no eggs hatched below 12°C and nearly all hatched at c.l6°C. Hatching time decreased with increasing temperature and the relationship between the two variables within the range 12–28 °C was well described by a power law. The length of the hatching period was less than 12 days. Hatching times estimated from the power-law equations and those obtained in the field experiments were similar. Therefore both the hatching time and the length of the hatching period in the field could be estimated from the laboratory data for the range 12–28°C.2. The maximum number of instars from egg to imago was 11; the average body length increment (mm) per moult was proportionately constant at c.26% and Dyar's rule was applicable. The interval between moults decreased with increasing temperature up to the seventh instar and the relationship between the two variables within the range 12–28°C was well described by a power law. The moulting interval for instars 8–11 ranged from 23 to 48 days and was relatively independent of temperature. No moulting occurred at temperatures below 12°C.3. Larval growth was logistic in the laboratory and variations in mean logistic growth rate (range 0–2.5% length day−1) were related to mean temperature with no growth at temperatures 〈12°C. Larval growth rates in pond experiments were similar to those estimated from laboratory data, and therefore the regression equations obtained from the laboratory experiments are probably applicable to larval growth in the field.4. Information on the life cycle of C. puella is briefly reviewed and it is concluded that C. puella from the pond near Herzogenburg has an univoltine life cycle.

Notes: SUMMARY. 1. Changes in species composition of the periphyton of an oligotrophic. Sierra Nevada stream continuously dosed for 1 year at three concentrations of copper (2.5, 5 and 10 μg 1−1 CuT; approximately 12, 25 and 50 ng 1−1 Cu2+) were determined.2. The numerically most abundant taxa were Bacillariophyceae (Achnanthes minutissima, Cocconeis placentula, Cymbella microcephala, C. sinuata, Fragilaria conslruens, F. crotonensis. Navicula spp., Synedra acus and S. rumpens), and the Cyanophyta Lyngbya spp., a co-dominant during spring and summer.3. Population densities of Lyngbya spp. were markedly reduced at all test concentrations of copper. Population densities of the principal Chlorophyta (Spirogyra spp. and Cladophora spp.) and the diatom Amphipleura pellucida were reduced at 5 μg 1−1 CUT. Of the twenty-two most abundant taxa, sixteen were reduced in abundance by continuous exposure to 10 μg 1−1 CuT.4. There was no commensurate reduction in standing crop (total number of individuals of all taxa). Achnanthes minutissima, a co-dominant in the control, was the primary replacement species. Other taxa that were more abundant at 5 μg1−1 CuT than in the control were Ceratoneis arcus, Cocconeis placentula, Navicula spp. and Synedra rumpens. Only A. minutissima and Calothrix spp. were more abundant at 10 μg 1−1 than in the control.5. Three resemblance measures (Canberra metric, Bray-Curtis and Dice) and diversity (Brillouin's) were evaluated for detecting differences in species composition among experimental stream sections. The Canberra metric, an index sensitive to proportional rather than absolute differences, was the most informative of these indices.

Notes: SUMMARY. 1. During a 2-year study of the fish and macroinvertebrates of a third-order montane stream, a severe drought in the first year resulted in a temporary cessation of surface flow. Flow was continuous during the second year.2. Some taxa (e.g. Ophiogomphus severus) exhibited higher density during the drought year, others declined in abundance during low flow (e.g. Baetis spp.), whereas a few (e.g. Tricorythodes minutus) appeared unaffected. Total macroinvertebrate density decreased by 50% during the low flow year compared to the normal flow year. Mayflies were most severely affected, but also exhibited the most dramatic recovery.3. The collector-gatherer functional feeding group was abundant only during the normal flow year, whereas shredders and predators exhibited increased relative abundance during low flow.4. Fish populations were severely reduced in the low flow year. However, fishes rapidly invaded the area following resumption of normal flow.

Notes: SUMMARY. 1. This review considers the periodic cycles of species dominance in a wide selection of temperate lakes. By ascribing individual species to assemblages, a high incidence of similarity among periodic cycles is demonstrated. Reference to lakes at high and low latitudes, as well as to rivers, shows conformity to parts of the same broad patterns.2. The role of population dynamics in shaping community structure is emphasized. Two types of change are recognized: autogenic, undirectional subsequences (successions), regulated by specific responses to critically changing resource-ratio gradients; and allogenic changes, regulated by variability in the physical environment.3. Analysis of the responses of representative species to allogenic change permits further grouping of the assemblages. These groupings coincide with clear morphological distinctions among the same phytoplankton species according to their unit sizes and surface area/volume ratios.4. It is argued that these properties condition the physiological responses of algae to seasonal variations in temperature, mixing and exposure to the underwater light field. The responses are compounded by relative resistances to loss processes (sinking, grazing), by short-term photosynthetic adaptation and vertical migratory behaviour.5. Graphical summaries are presented that relate the morphologically-, physiologically- and behaviourally-mediated responses to a hierarchy of physical, chemical and biotic environmental variables. Phytoplankton periodicity is the outcome of these interactions.