bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumption of Atlantic salmon smolts and parr by goosanders: estimates from doubly‐labelled water measurements of captive birds released on two Scottish rivers
Authors: Feltham M. J.
Published: June 2006

The field metabolic rates (FMRs) of nine captive goosanders,Mergus merganser, released on two Scottish rivers were estimated using the doubly‐labelled water (DLW) technique. Mean (± S.E.) FMR was 2.322±0.239ml CO2g−1h−1and daily energy expenditure (DEE) 1939 ± 184 kJ per day. This was significantly greater (x 1.5) than previous estimates which assumed DEE to be three times the basal metabolic rate (BMR) based on regression equations predicting BMR from body mass. FMR of captives and dietary data from previous studies were used to estimate daily consumption of salmon,Salmo salar, smolts and parr by natural populations of these ducks on the river North Esk, north‐east Scotland. Goosanders are likely to consume 480‐522 g fish per day of which two‐thirds are juvenile salmon; equivalent to a daily intake of 10‐11 smolts and 48‐52 parr. Annual predation of smolts by goosanders was estimated to be between 8000 and 15 000 or 3 and 16% of annual production.
Effects of 2‐methylisoborneol (MIB), and ethanol on the expression and activity of cytochrome P450s from the channel catfish
Authors: Schlenk D. , Ronis M. J. J. , Miranda C. , Buhler D. R.
Published: June 2006

Injection of 1 mg kg−1 of 2‐methylisoborneol (MIB) caused an increase in a CYP1A‐like protein of approximately 56 kDa from the kidneys of juvenile channel catfish as determined by western blot analysis using antibodies raised against trout CYP1A1. Ethoxyresorufin O‐deethylase activity from kidneys of MIB‐injected fish was significantly elevated as compared to ethanol‐injected controls. Static exposure of juvenile channel catfish to 10 ppm MIB caused a statistically significant induction of a CYP2K‐like protein of approximately 53 kDa from the livers of treated catfish as determined by western blot analysis using antibodies raised against trout CYP2K1. Treatment of juvenile channel catfish with ethanol (1 ml kg−1) reduced the expression of one kidney and two constitutive liver P450s, while increasing another kidney form. There was no difference in carbon tetrachloride‐induced lipid peroxidation in livers after ethanol treatment. Thus, MIB and ethanol affect the expression of at least three P450 isoforms in channel catfish tissues.
Structure of the exocrine pancreas of flounder (Paralichthys olivaceus): immunological localization of zymogen granules in the digestive tract using anti‐trypsinogen antibody
Authors: Kurokawa T. , Suzuki T.
Published: June 2006

Most fish have a diffuse exocrine pancreas located around the internal organs, but its exact structure is not well understood. In this study, we developed a method for analysing zymogen granules using anti‐fish trypsinogen, and the structure of the flounder pancreas was examined by localizing pancreatic exocrine cells. Anionic trypsinogen was purified from eel pancreas by chromatography using DE‐52‐cellulose and Superose 12 columns. Rabbit antiserum (anti‐eel trypsinogen antibody: anti‐eTrg) was raised against purified trypsinogen. Immunoblotting analysis demonstrated that anti‐eTrg recognized two isoforms of eel trypsinogens and trypsins. This antibody also reacted with flounder trypsin. Zymogen granules containing trypsinogen were visualized within pancreatic glandular cells of the flounder Paralichthys olivaceus by immunohistochemistry using anti‐eTrg. The flounder exocrine pancreas was reconstructed from observations of serial sections of digestive tract. The exocrine pancreas cells were localized along the hepatic portal vein and the veins running to the portal vein from the intestine, stomach, pyloric appendage and spleen, forming a highly branched tissue. Interlobular ducts from pancreatic acini formed a pancreatic duct covered with smooth muscle at the point where it met (but did not join) the bile duct. The pancreatic duct opened into the intestinal lumen at the basal portion of the third pyloric appendage in parallel with the bile duct.
Medium‐term organ culture for teleost fish retinae
Authors: McCormack C. A. , McDonnell M. T.
Published: June 2006

Whole retinae from Midas cichlids Cichlasoma citrinellum were maintained successfully in superfusion culture for 21 days post‐removal and continued to exhibit normal light‐ and circadian‐driven cone movements.
Notes on porbeagle sharks, Lamna nasus, from the Bristol Channel
Authors: Ellis J. R. , Shackley S. E.
Published: June 2006

In a sample of 71 Lamna nasus from the Bristol Channel, most were juveniles. Males, which outnumbered females, matured at about 165 cm. Their diet was composed of fish and cephalopods.
Effects of triploidy on rainbow trout myogenesis in vitro
Authors: Greenlee A. R. , Kersten C. A. , Cloud J. G.
Published: June 2006

To examine the effects of triploidy on rainbow trout myogenesis in vitro, mononuclear cells were liberated enzymatically from the lateralis muscles of diploid and triploid trout. The muscle of diploids yielded 1 × 106± 1 × 105 (±s.e.m.) mononuclear cells g−1 muscle compared to 0.7 × 106± 8 × 104 cells g−1 from triploids (P<0.01). The plating efficiencies of diploid and triploid mononuclear cells on Matrigel™ following 18 h of culture in Leibovitz's L‐15 + 10% foetal bovine serum were not significantly different, 35.0 ± 3.5% and 33.0 ± 2.9%, respectively. For most time points examined, the proportion of nuclei in multinucleated cells and the proportion of nuclei in myosin positive cells were not significantly different for diploid and triploid trout. Taken together, these data suggest that diploid and triploid myogenic cells will differentiate similarly when compared under identical, in vitro conditions.
Changes in monogenean and copepod infestation on captive Acanthopagrus australis (Sparidae)
Authors: Roubal F. R.
Published: June 2006

Infection levels by 17 species of ectoparasite on 491 yellowfin bream collected throughout 1990 from Moreton Bay, S.E. Queensland were compared to infections on 82 bream collected during the same period from a captive population in a large pond at Sea World, Gold Coast, Queensland. There was a significant increase in prevalence and/or intensity of monogeneans Lamellodiscus acanthopagri and Polylabroides multispinosus, but a decrease in the monogenean Anoplodiscus australis and the copepods Ergasilus australiensis, Lernanthropus atrox, Bomolochus stocki and Alella macrotrachelus on captive fish. Twenty‐eight bream collected from the pond during autumn were placed in an experimental 1 m3 cage within the pond for 4–6 weeks. Compared to the baseline data for the pond, the caged fish showed increased prevalences of the monogeneans Lamellodiscus acanthopagri, L. squamosus, L. major and Haliotrema spariensis, and increased intensities of L. squamosus, Allomurraytrema robustum and P. multispinosus. The copepod Caligus epidemicus dropped off in preservative, but its abundance (average number per fish) was significantly higher on caged fish than on pond or wild fish. Increased infection levels by L. acanthopagri and A. robustum were due in part to autoinfection. The large skin area promoted large populations of C. epidemicus.
Evaluation of the effects of cryopreservation of isolated erythrocytes and leukocytes of largemouth bass by flow cytometry
Authors: Fisher S. K. , Lingenfelser J. T. , Jagoe C. H. , Dallas C. E.
Published: June 2006

We examined the effects of separation and freezing on fish leukocyte and erythrocyte morphology by light microscopy and on DNA content as measured by flow cytometry (FCM). Leukocytes and erythrocytes of largemouth bass Micropterus salmoides were isolated by density gradient centrifugation of whole blood, and frozen in liquid nitrogen in a buffer containing DMSO as a cryopreservative. The coefficient of variation (CV) of the G0/G1 peak of the cells was used to assess variation in nuclear DNA content within cell populations before and after separation and freezing treatments. In erythrocytes, the CV did not change significantly (P>0.05) when nuclei were isolated and stained without freezing or when erythrocytes were frozen prior to nuclear isolation and staining. In leukocytes, freezing and thawing prior to isolation and staining of nuclei significantly increased the CV (P<0.05), and produced hyperdiploid shoulders of the G0/G1 peak. However, the CV of leukocyte nuclei that were isolated and stained prior to freezing and the CV of non‐frozen leukocyte nuclei did not differ (P>0.05). Microscopy showed that the freezing protocol had little effect on erythrocyte morphology, but caused irregular swelling in leukocytes. Freezing intact leukocytes also significantly (p<0.05) altered the apparent distribution of cells among the phases of the cell cycle as measured by FCM. The distributions of leukocyte nuclei that were isolated and stained prior to freezing were not different to non‐frozen leukocytes. DNA measurements of nucleated blood cells are widely used in physiological, genetic and toxicological studies. Our results suggest that whole blood and erythrocytes for use in such studies can be frozen whole using a simple protocol, but leukocyte nuclei must be isolated and stained before freezing to avoid serious artifacts.
Compensatory growth in Alaska yellowfin sole, Pleuronectes asper, following food deprivation
Authors: Paul A. J. , Paul J. M. , Smith R. L.
Published: June 2006

During the early spring four groups of sub‐adult Pleuronectes asper were fasted for either 0, 2, 4 or 6 weeks at the beginning of a 12‐week experiment, then fed to satiation to examine their ability to compensate with faster growth after food deprivation. All fish increased their stored energy reserves markedly and at the end of the experiment all four groups had similar body energy content (J g−1), length gains and dry weight to wet weight ratios. The groups of yellowfin sole fed continuously or fasted for 2 weeks gained the most weight, 25 and 24% respectively. Fishes fasted either 4 or 6 weeks exhibited significantly lower weight gains of 16 and 15% respectively over the 12‐week experiment. Because of this disparity in weight gain the total body energy content of the continuously fed fish and those fasted for only 2 weeks increased by approximately 60 vs 46% or 35% for sole fasted for 4 or 6 weeks.

The experiment showed P. asper had a limited capacity for compensatory growth. When food was scarce yellowfin sole allocated energy preferentially to growth in length instead of weight. These findings may account for some of the interannual differences in mean length and weight at age for yellowfin sole from the Bering Sea where variations in extent and duration of ice cover and the boreal bottom water delimit the growing season.
The uptake of macromolecular materials in the hindgut of viviparous rockfish embryos
Authors: Takemura A. , Takano K. , Takahashi H.
Published: June 2006

Regions of the gut of near‐term embryos and new‐born larvae of the viviparous rockfish Sebastes taczanowskii were examined histologically and immunohistochemically in order to ascertain whether they possessed the potential to absorb intact macromolecules. Compared with the hindgut of larvae 24 h after parturition, that of near‐term embryos (stage 31) was found to be markedly hypertrophied and to react positively when tested for the presence of eosinophilic materials and with antibodies raised against extracts of the rockfish yolk (ab.a‐E). In addition, near‐term embryos incubated in Ringer solution containing 1% bovine serum albumin appeared to accumulate the protein within the epithelium of the hindgut. Furthermore, as confirmed by immunodiffusion analysis, the ovarian fluid contained materials which reacted positively to ab.a‐E. These results suggest that ingestion of intact macromolecules occurs during the late embryonic stages and that the yolk‐like substances detected within the hindgut epithelium of such embryos may be derived from the bathing ovarian fluid.
Turning radius of yellowfin tuna (Thunnus albacares) in unsteady swimming manoeuvres
Authors: Blake R. W. , Chatters L. M. , Domenici P.
Published: June 2006

The specific turning radius of yellowfin tuna Thunnus albacares Cuvier is large relative to that of other fish (0.47 total body length ± 0.18, mean ± 2 s.e.). We argue that specializations for efficient steady swimming compromise performance in transient turning manoeuvres.
Lilliputian bottom fish fauna of the Hatteras upper middle continental slope
Authors: Sulak K. J. , Ross S. W.
Published: June 2006

Submersible data from two areas along the Carolina‐Virginia continental slope reveal a Hatteras upper middle slope (HMS) (35.30’N, 74.50’W) demersal fish fauna remarkable for diminutive size of individuals within and across species, a fauna which is accordingly termed ‘Lilliputian’. Contrast of HMS submersible data with Virginia trawl and submersible data support this finding. The four top‐ranking HMS fishes, Lycenchelys verrillii, Glyptocephalus cynoglossus, Myxine glutinosa and Nezumia bairdii, are all significantly smaller than on the Virginia upper middle slope. Also peculiar to the HMS is the dominance of sedentary benthic species, rarity of active benthopelagic foragers, and markedly elevated fish population density. Species composition of the HMS fauna differs from that of the general Middle Atlantic Bight fauna; notably absent are species of otherwise continuous distribution along the U.S. East Coast (e.g. Synaphobranchus affinis, Nezumia aequalis). Since HMS megafaunal and macrofaunal invertebrate communities are also anomalous, the Lilliputian phenomenon among HMS bottom fishes provides a characteristic biotic signature of a pervasively re‐structured benthic boundary layer community. The authors hypothesize that the HMS faunal anomaly reflects a limiting factor, episodic sediment surface hypoxia, peculiar to this region of high particulate organic carbon flux from surface waters. Results indicate that substantial changes in fish faunal composition and structure can occur on a small geographic scale on the open soft‐Substrate continental slope.
Catch and discards from experimental trawl and longline fishing in the deep water of the Rockall Trough
Authors: Connolly P. L. , Kelly C. J.
Published: June 2006

Comparative bottom trawl and longline surveys were carried out on two chartered commercial fishing vessels in the deep waters (350‐1300 m) of the Rockall Trough, an area subjected to heavy commercial exploitation. The species composition, catch rates and length distributions from each survey were very different and reflected the fundamental difference in the two types of fishing operations. Bottom‐trawled catches produced greater species diversity and higher discard rates. Longline catches produced larger specimens of teleost fish and were dominated by squalid shark. Trawl discards, expressed as kgs of discards per tonne of roundnose grenadier Coryphaenoides rupestris landed, were calculated for a broad range of the most abundant species taken in the catch. First estimates of total international discarding from deep‐water trawling operations in the Rockall Trough area (7530 tonnes; 26.5 million individuals) were made by raising the discard rates using international grenadier landings for 1995. The outlook for the continued exploitation of the deep‐water fish resource in the Rockall Trough and possible management options are discussed.
Retinal specializations in the eyes of deep‐sea teleosts
Authors: Collin S. P. , Partridge J. C.
Published: June 2006

Although living beyond the penetration limits of sunlight, many deep‐sea teleosts possess large eyes, lenses capable of accommodation, and various adaptations for increasing sensitivity and extending their visual field. However, little is known of the extent of the visual field and whether the spatial resolving power of the eye is constant across the retina. In order to examine whether these fish are specialized for acute vision in particular regions of their visual field, retinal wholemounts were used to examine the regional differences in the density of retinal ganglion cells in 16 species from different depths, habitats and photic zones. It was found that the retinal ganglion cell topography changes markedly across the retina with a density range of 6.3–50.6 × 103 cells mm−2 in a pattern unique to each species. A number of mesopelagic species including the lanternfishes, Lampanyctus macdonaldi and Myctophum punctatum possess a concentric increase in cell density towards the retinal margins, putatively enhancing peripheral vision. Three tubular‐eyed species including Scopelarchus michaelsarsi possess an area centralis in the centro‐lateral region of the main retina supporting the premise that this specialization receives a focused image. Some benthic species such as the smoothhead Rouleina attrita and the searsid Searsia koefoedi also boast a structural specialization or fovea in temporal retina with centro‐peripheral cell gradients exceeding 30 : 1. Benthic species such as the tripodfish Bathypterois dubius possess two regional increases in ganglion cell density or areae centrales, one nasal and the other temporal, thereby increasing spatial resolving power in the caudal and rostral visual fields, respectively. These quantitative analyses suggest that deep‐sea fishes, like their shallow‐water counterparts, also use a specific region of their visual field for acute vision. This may be an advantage for the detection and localization of bioluminescent light sources.
Comparative character of the deep‐water and inshore cottoid fishes endemic to Lake Baikal
Authors: Sideleva V. G.
Published: June 2006

Lake Baikal's 29 endemic species of cottoid fishes form three groups: shallow‐water species in depths to 350 m; eurybathic species from 50 to 1300 m; and abyssal species from 400 to 1600 m. These groups differ in their abilities to withstand high hydrostatic pressure. As in marine deep‐water fishes, abyssal cottoids in Baikal have few or no cones in the retina, and some have tubular eyes. Their seismosensory systems predominate, based chiefly on free neuromasts. The proportion of species with canal systems decreases with depth. Diversity of the predominantly gammarid foods also decreases from 45 species in shallow water to five species in deep water, and the lateral line system plays the dominant role in food detection at all depths. Two abyssal cottoids have become secondary pelagic, achieving close to neutral buoyancy through high lipid levels and reduced skeletal mineralization. These forms take advantage of the abundant pelagic planktonic amphipod populations. The adaptations of abyssal forms parallel those seen in deep‐water marine fishes.
A comparison of the deep‐water demersal fish assemblages of the Rockall Trough and Porcupine Seabight, eastern North Atlantic: continental slope to rise
Authors: Gordon J. D. M. , Merrett N. R. , Bergstad O. A. , Swan S. C.
Published: June 2006

Fishery surveys of the continental slope to the west of the British Isles have shown quite marked differences between areas in both the proportion and abundance of marketable or potentially marketable species. In general, the northern slopes lying to the west of Scotland were considered to have a greater potential for exploitation than the southern slopes off Ireland. Subsequent detailed studies of a northern (Rockall Trough) and a southern slope area (Porcupine Seabight) sampled the demersal fish fauna using a Granton trawl fished on paired warps to depths of 1200 m, and a semi‐balloon trawl fished on a single warp to depths of about 3000 m. The Granton trawl catches differed significantly between the two areas, especially at the greatest depths fished. The semi‐balloon trawl catches did not differ between the areas. This slower trawl was poor at catching large, mobile species and efficient in the capture of the deep‐waler eel Synaphobranchus kaupi. This eel was numerically dominant over the mid to lower slope and probably accounts for much of the similarity between areas at these depths.
Bathymetric distribution and growth patterns ofBathypterois mediterraneusfrom the north‐western Mediterranean Sea
Authors: Morales‐Nin B. , Massutí E. , Stefanescu C.
Published: June 2006

Bathypterois mediterraneuswas collected on 148 bottom trawls between 147 and 2251 m depth in the north‐western Mediterranean. The species appeared below 700 m, its relative abundance and biomass increased progressively and reached its maximum at 2100‐2300 m. A total of 1913 specimens were measured, ranging from 4 to 20 cm standard length (Ls). The size composition with depth did not show any specific trend, and no modal progression could be distinguished in the length frequency distribution by cruise, with dominance of large fish (13‐15 cmLs) and a unimodal size pattern. The otoliths of 173 specimens were examined and showed the ring pattern common to teleost fishes. The age ranged between 0 and 15 years, although specimens of 4‐12 years old were the most abundant. The growth parameters and the growth curve obtained from the interpretation of the growth rings in otoliths showed a low growth rate.
Validation of age readings from otoliths of juvenile roundnose grenadier, Coryphaenoides rupestris, a deep‐water macrourid fish
Authors: Gordon J. D. M. , Swan S. C.
Published: June 2006

Validation of the ageing of deep‐water fish is difficult and there are only a few instances where the rings on the otoliths have been shown to be laid down annually. Roundnose grenadier have been fished commercially in the North Atlantic since the 1960s and the adult fish have frequently been aged by counting the rings in otoliths or scales. All the ageing was done on the assumption that the rings in the otoliths or scales were annual. Between 1975 and 1992, the Scottish Association for Marine Science carried out seasonal trawling surveys in the Rockall Trough using a fine‐meshed trawl, and collected otoliths from a wide size range of roundnose grenadier. An examination of the growing edge of otoliths from juvenile fish from these collections suggests that the rings in the otoliths are laid down annually. The broader, opaque zones which represent the growth phase were dominant between September and March. The thinner, hyaline zones were dominant between April and July. The apparent delay in the growth phase compared with most shallow‐water species is discussed in relation to the availability of mesopelagic prey.
Population structure in the pan‐oceanic wreckfish,Polyprion americanus(Teleostei: Polyprionidae), as indicated by mtDNA variation
Authors: Sedberry G. R. , Carlin J. L. , Chapman R. W. , Eleby B.
Published: June 2006

The wreckfishPolyprion americanus, a large [>1 m total length (LT)] demersal teleost, is distributed globally in temperate waters, including both sides of the North and South Atlantic Oceans, the Mediterranean, the western South Pacific, and the southern Indian Ocean. Wreckfish spawn off the south‐eastern U.S. on an area of the Blake Plateau (the Charleston Bump) characterized by an extensive ridge having approximately 100 m relief, in 450–600 m depths. Juvenile wreckfish (<60 cmLT) are pelagic and, in the North Atlantic, are not reported from the Blake Plateau fishing area, but occur in by‐catch and fishery landings in the eastern Atlantic. Analysis of nine restriction fragment length profiles from a PCR‐amplified fragment (∼1.5 kb) of the ND1 mitochondrial gene indicated no stock separation between eastern North Atlantic (Azores, Majorca, Madeira), and western North Atlantic (Blake Plateau) wreckfish. Restriction site differences separate western South Atlantic wreckfish from the North Atlantic; however, South Atlantic wreckfish share restriction‐site similarities with western Pacific wreckfish that are not shared with North Atlantic wreckfish. North Atlantic circulation provides a mechanism for a long‐lived pelagic stage to be dispersed from Blake Plateau spawning grounds to the eastern North Atlantic. Global circulation patterns may explain both the dispersal of mtDNA haplotypes and the disjunct distribution of wreckfish body lengths in a temperate, deep‐water vagile species with an extended pelagic juvenile stage such as wreckfish.
Fluctuating asymmetry in the otoliths of larval fish as an indicator of condition: conceptual and methodological aspects
Authors: Somarakis S. , Kostikas I. , Tsimenides N.
Published: June 2006

Developmental instability, measured as fluctuating asymmetry (FA) in bilateral traits, has been used widely as an indicator of genetic or environmental stress in a variety of plant and animal taxa. FA arises as small deviations from perfect bilateral symmetry which reflect ‘mistakes’ in developmental processes resulting from the inability of the genotype to buffer itself effectively against environmental perturbations. Recently, it has been proposed that FA in the otoliths can be used as an indicator of condition in larval fish. This paper reviews the conceptual and methodological aspects of FA relevant to its potential use as a measure of well‐being. Its simplicity makes FA an attractive tool to measure developmental precision and condition. However, there are several pitfalls, such as measuring error or potentially size dependence. Subtle asymmetries, i.e. between sides variation of a trait at the individual level, may not always be indicative of condition and should be interpreted with caution. The past‐growth record of otoliths may provide a powerful means of studying the development of asymmetries at the level of the individual.
The estimation of food consumption in larval and juvenile fish: experimental evaluation of bioenergetics models
Authors: Karjalainen J. , Miserque D. , Huuskonen H.
Published: June 2006

The two most commonly used methods for estimating the food consumption of fish are based on either the evacuation rate of food or the energy budget of an individual fish. In this study, both of those methods were used to estimate the food consumption of fish under experimental conditions. Bioenergetics models of vendace Coregonus albula, smelt Osmerus eperlanus, roach Rutilus rutilus and perch Perca fluviatilis were reconstructed based on experimental data and published values. The precision of the bioenergetics estimates for food consumption was evaluated under experimental conditions. The modelling efficiency (EF) of the bioenergetics model was 0.90, 0.97 and 0.93 for coregonids, roach and perch, respectively, which indicated good agreement between observed and predicted values. Under our experimental conditions, the bioenergetics model estimated food consumption better than the evacuation rate model.
Patterns of prey size and taxonomic composition in larval fish: are there general size‐dependent models?
Authors: Pepin P. , Penney R. W.
Published: June 2006

The allometric relationship of maxilla length to larval fish weight approached a slope of 1/3 for 11 species from Conception Bay, Newfoundland. In 10 of these species, mean prey size increased with length of the maxilla but not constantly. In six species, niche breadth increased with length of maxilla. The rate of change in niche breadth was inversely related to the rate of change in mean prey size. Nauplii and copepodites of calanoids were selected positively, and cyclopoids negatively for almost all species of larval fish.
Individual‐based modelling of recruitment variability and biomass production of bay anchovy in mid‐Chesapeake Bay
Authors: Wang S. B. , Cowan J. H. , Rose K. A. , Houde E. D.
Published: June 2006

Production of bay anchovy Anchoa mitchilli is highest in the larval and juvenile stages. The interplay between vital rates, stage durations, prey resources, and anchovy abundance ultimately determines the relative magnitude of recruitment (which in the model varies by about three‐fold) and of stage‐specific production. Changes in adult seasonal spawning patterns that increase the number of larval survivors result in only a slight increase in overall production due to density‐dependent decreases in growth rates of later life stages. Bay anchovy in the mid‐Chesapeake Bay may reach a compensatory threshold during late summer‐autumn as fish growth is affected by competition for food resources. Density dependence in the population is evident in the relationships between spawner‐recruit, size‐recruit, and production of larval or juvenile to young‐of‐the‐year life stages. Density‐dependent growth acts differentially upon the early life stage that exceeds the compensatory threshold in any given year, due either to environmental variability or population size, or both. This could explain partially the relatively low recruitment variability observed for this anchovy.
Prey size spectra and prey availability of larval and small juvenile cod
Authors: Munk P.
Published: June 2006

The aim of the present study is to describe the prey preference characteristics of cod larvae and assess preference variability in relation to species and size composition of copepod prey. A further aim is to examine the hypothesis that dietary prey size spectra remain the same during the larval stage when viewed on a relative predator/prey size scale. The study is based on stomach analysis of larval/juvenile cod in the size range 10–35 mm from nursery grounds in the North Sea. Stomach contents (species, size) were compared to environmental composition and preference indices were calculated. Prey size spectra had the expected relationship to larval cod size, and preference for given copepod species could be ascribed to their relative size. Additional species‐specific preferences were evident, for example the larger Pseudocalanus and the larger Calanus spp. were highly preferred. Available prey biomass was highest in the areas of a hydrographic front, where larvae have been shown to concentrate. Changes in prey availability with larval growth depend strongly on specific prey biomass spectra at a given location. Both increasing and decreasing prey availability at increasing larval size were indicated, dependent on location. The findings illustrate the usefulness of coupling dietary prey size spectra and biomass spectra of available prey sizes during studies of ichthyoplankton feeding ecology.
SEDIMENTATION AS A MEANS OF CLASSIFYING EXTREMELY FINE CLAY PARTICLES1
Authors: Schurecht H. G.
Published: June 2006

A method is described for determining the rate of sedimentation of clays by measuring the suspended weights of a glass plummet suspended in a clay slip at different intervals of time. The specific gravity of the slip remaining in suspension may be calculated as follows: S = Pd‐Ps/Pd‐Pw where S is specific gravity of slip, Pd is dry weight of a plummet in grams, Pw, is suspended weights of plummet in distilled water and Ps, is suspended weight of plummet in clay slip. The average weight of clay per cc. is calculated as follows: Cw= D(S‐d)/D‐d, where Cw, is average weight of clay per cc., D is the specific gravity of clip and D is the specific gravity of water.

It is impractical to separate by elutriation, clay particles smaller than 0.003 mm. which constitute 50–100% of many clays.

It is possible to classify particles as small as 0.0001 mm. by the plummet sedimentation method and the results are more uniform than those obtained by elutriation.
USE OF SPECIAL OXIDES IN PORCELAIN BODIES1
Authors: Geller R. F. , Woods B. J.
Published: June 2006

Substitution of special oxides for flint.—The oxides of thorium, titanium and zirconium and the silicate of zirconium were used. Variations in composition were based on batch weights, the percentage of oxide (or silicate) increasing from 27 to 49% with a corresponding decrease in feldspar content. A similar series using flint was also made a basis for comparison.

Effect of special oxides on drying and burning behavior, dielectric strength and resistance to spang.—(1) Rutile causes high drying and burning shrinkage. The burning range is long but softening in every case results above cone 12. Resistance to spalling is above normal. (2) Thoria produces a body with a long burning range and great refractoriness. Drying shrinkage is normal, burning shrinkage very high, resistance to spalling very low, and the bodies warp badly. (3) Zirconia bodies have a normal drying shrinkage and a high burning shrinkage, no warping, long firing range, and the highest resistance to spalling. (4) Zircon.—The zirconium silicate bodies soften at temperatures below cone 18 and the firing range is short. Drying and burning shrinkage are similar to flint bodies but resistance to spalling is above normal.

Effect of oxides on dielectric resistance.—No effect on dielectric resistance is obtained through the use of the special oxides mentioned.
POROSITY: I. PURPOSE OF THE INVESTIGATION II. POROSITY AND THE MECHANISM OF ABSORPTION1
Authors: Waseburn Edward W.
Published: June 2006

Significance of porosity.—This is briefly outlined.

Standard reference method.—The requirements of an engineering testing method are simplicity, rapidity and convenience with no more accuracy than practical considerations justify. There should, however, be also available a standard reference method, that is, a laboratory method where accuracy is the main requirement.

Types of pores.—Six types of pores are described and the process of absorption under various conditions is analyzed.

Defitions.—Definitions are proposed for the terms, permeability, penetrability, absorptivity, porosity. bulk density, closed‐pore space and “cracks” and “holes,” and methods of measurement are suggested.
DISCOLORATION OF WHITEWARE FIRED IN CARBORUNDUM Saggars1
Authors: Spurrier H.
Published: June 2006

The author advances the hypothesis that iron carbonyl, formed by reaction between CO and iron present in the carborundum saggars, condenses in the central portion of the bung, trickles down over the ware and is later decomposed, giving iron and free carbon, which are absorbed and color the ware. Laboratory experiments completely confirmed this hypothesis.
A SIMPLE EXPANSIBILITY TEST FOR DETERMINING THE WELDING PROPERTIES OF GLASSES1
Authors: Sharp Donald E.
Published: June 2006

Simple method of determining the relative expansibilities of two glasses.—Place two rods of glass side by side with the ends flush, heat these ends, weld together by pinching with forceps and then pull out a thread or thin strip with the two glasses forming opposite sides. When cool the thread will bend toward the glass having the higher total expansion up to the softening point of the softer glass. This test may be used for quantitative determination of coefficieots of expansion if a series of glasses of known expansibilities are available for comparison. The method is of particular value for investigating the welding properties of glasses, for whether or not two glasses can safely be welded together may be determined directly from the amount of curvature of the thread.
THE DESIGN AND OPERATION OF GLASS HOUSE FURNACES*
Authors: Denk F. J.
Published: June 2006

Design and operation of glass house producer‐gas furnaces.—After discussing the proper design of checker chambers, two inefficient designs are criticised. The gases being cooled should move downward and the gases being heated should move upward, and the dimensions should be based on actual working data. The location of the ports is important and heat insulation should be carefully considered. The reversing valve should be efficient and operated regularly; and the performance of the furnace should be constantly watched with the help of instruments such as draft recorders and thermocouples, and the waste gases should be analyzed frequently. With care in design and operation it should be possible to approach the performance of a certain furnace which gave 3 lbs. of glass for each pound of coal burned.
THE MUTUAL RELATIONS BETWEEN ART AND TECHNÓLOGY1
Authors: Solon Leon V.
Published: June 2006

An analysis of the purpose of decoration and of the characteristics of bodies, colors and glazes which determine their acceptability for the purposes of the professional decorative artist. The author urges the establishment of an Annual Exhibition where American ceramic artists may exhibit their products along side those of the sculptors, mural painters and other artists.
AN ELECTRIC VITREOUS ENAMELING OVEN1
Authors: Mehling C. W. , Carpenter Jas. W.
Published: June 2006

Comparison with older types of furnaces.—In marked contrast with the oil, coal and gas furnaces the electric furnace eliminates damaged ware and makes possible the utilization of the entire heating space. Its initial cost and the fuel costs are double those of the older types but it admits 25 per cent increase in weight per charge and 30 per cent in charges per hour.

Description and operation.—Details of construction are given. The electrical equipment is explained together with the methods of temperature record and control. Details of operation are given.

Cost of operation.—With an initial cost of $8000, the cost of the electrical power has been $2.00 per hour for a 10‐hr. day which would be reduced to $1.56 per hr. for a 24‐hr. day.

Production results.—With a production of 900 lbs. of ware per hr. the enamel finish is more satisfactory than with the older types of furnaces.

Future improvements.—Preheating chambers and double end operation are suggested.
THE LAYOUT OF A BRICK OR TILE PLANT WITH A CAR TUNNEL KILN.1
Authors: Garve T. W.
Published: June 2006

Description of a hollow tile and drain tile plant using a tunnel kiln. The routing of the material (shale) and product is described under the following heads: dump cars, plate feeder and crusher, storage, dry pans, screens, storage, pug mill and tile machine, combination waste heat and radiated heat drier, kiln car loading station, tunnel kiln, kiln car unloading station, stock shed. A detailed diagram is given.
THE RELATION BETWEEN THE FINENESS AND OTHER PROPERTIES OF CALCINED GYPSUM1
Authors: Emley W. E. , Welch F C.
Published: June 2006

Experimental methods.—The normal consistency was measured by the Southard viscosimeter. the time of set by the Vicat needle, and the plasticity by spreading upon a porous porcelain plate.

Conclusions.—(1) Normal consistency is obtained with less water the coarser the calcined gypsum, (2) the finer the material the shorter the time of set, (3) the finer the calcined gypsum the stronger is the set material until the degree of fineness beyond that of size 6 (A. S. T. M. spec.) after which increase in fineness is accompanied by decrease in strength, (4) the finer the calcined gypsum the more sand it will carry.
SOME RELATIONS OF COMPOSITION TO SOLUBILITY OF ENAMELS IN ACIDES1
Authors: Staley Homer F.
Published: June 2006

Review of literature.—The literature on acid resisting enamels and glasses is reviewed.

Acid resisting powers produced by different oxides.—When substituted one for another, in each case in equal percentage amounts, various oxides and minerals increased the resistance of various enamels to the action of boiling 20 per cent hydrochloric acid in the following order of effectiveness: Al2O3, cryolite, Na2O, PbO, BaO, Li2O, MgO, CaF2, ZnO, SrO, CaO, B2O3. The first five mentioned were especially effective. The remainder are undesirable materials from the standpoint of acid resistance.

Effect of the enamel base.—The relative effects of the materials were the same for various base enamel compositions.

Effect of ZrO2 and TiO2.—ZrO2 and TiO2, when substituted for small amounts of SiO2, increased the resistance of various enamels to attack by acids, ZrO2 being most effective in this respect. The favorable action of ZrO2, is offset by a tendency to produce excessive chipping. Rutile gives less chipping than either zirconia or silica and greater acid resistance than silica.

Best compositions.—Enamels 2,17,19,26,27, and 33 of table 1 showed resistance to action of the acid equivalent to that of the original competitions based on the analysis of a French acid‐resisting enamel. By use of the data developed in this investigation other highly acid‐resisting compositions can readily be formulated.
HIGH TEMPERATURE TESTING FURNACE1
Authors: Hepburn W. M.
Published: June 2006

A surface combustion furnace lined with alundum and fed by seven burners supplied from a mixture box in which an explosive mix. Of gas and air is made by a special inspirator melts down cone 36 in one hour using 156 cu. Ft. of city gas. The max. temp., 3400°F, attained is within 200°F, of the theoretical max. Advantages claimed are: Simplicity, low fuel consumption, ease of observation and measuring temperatures and ability to produce either neutral, reducing or oxidizing atmosphere.
THE EFFECT OF GLAZE COMPOSITION ON THE CRAZING OF TERRA COTTA1
Authors: Hill E C.
Published: June 2006

summary

Comparing the effects of equal molecular additions of the various components of the glazes in this study, it was found that ZnO and feldspar overcome crazing, ZnO being the more effective. MgO, BaO and CaO tend to produce crazing, MgO having the greatest tendency and the effect of BaO being somewhat greater than that of CaO. SnO2 has no effect on the crazing.

Increase of clay is more effective in overcoming crazing than any other changes that can be made in the glaze formula. Addition of small amounts of clay are more effective in overcoming crazing than much larger additions or substitutions of the other components.

Increase of flint (per molecular equivalent) is less effective in overcoming crazing than increase of either clay, ZnO or feldspar, although, generally, considerable more flint than clay or ZnO can be added without appreciably changing the maturing point of the glaze. In many cases, increase of flint will not overcome crazing in a glaze.
NICKEL OXIDE IN GLAZES1
Authors: Whitmer J. D.
Published: June 2006

Colors produced from NiO.—The literature on this subject published in the Transactions of the Society is briefly reviewed.

Effects of variations of RO in cone 6 glazes on colors from nickel oxide.—Red colors are produced when ZnO and BaO are used in certain proportions. Blues and purples of varied shades and hues are developed with varied combinations of ZnO, CaO and BaO. Grays are possible in presence of CaO and MgO.
NOTE ON THE EFFECTS OF FIRING TEMPERATURES ON THE STRENGTH OF FIRECLAY AND STONE WARE BODIES1
Authors: Schurecht H. G.
Published: June 2006

The cross breaking strengths, porosities and shrinkages of fire‐clay and stoneware bodies were determined after firing to different temperatures. It was found that with one exception, maximum strength was developed by firing to cone 8, even when porosity and shrinkage data showed the bodies to be over or underfired at this temperature. The cause of weakening above cone 8 may be due to the formation of sillimanite. Bodies which develop maximum shrinkage and minimum porosity at cone 8 have a greater ratio of fired strength to dry strength when fired to cone 8, than those which are under or overfired at cone 8.
THE WATER SMOKING OF CLAYS1
Authors: Geller R. F.
Published: June 2006

Experimental Method.—The water smoking behaviors of two plastic brick clays, one shale and one fire‐clay were studied by heating 4‐in. cubes at different rates, two thermo‐elements being buried in the brick and two others placed against the exterior surface.

Results of Conclusions.—To save time in water smoking, the ware should be previously dried not far from 100°C, good circulation should be provided in the kiln and the temp. of the interior of the product should not lag appreciably behind that of the kiln. It should be possible to water smoke heavy clay products in 15 hours with heating rate of 20°C per hour.
REFRACTORIES FOR OIL‐FIRED FURNACES AND BOILERS1
Authors: Grant W. H.
Published: June 2006

The failure of fire‐brick in oil fired furnaces results from (1) spalling and falling of side wall bricks, (2) disintegration of bricks in direct path of flame, (3) glazing of surface with green glaze which penetrates and weakens brick, and (4) erosion by flame. A plea is made for more research in the field.
NATIONAL REVIEW OF THE SAGGER SITUATION1
Authors: Simcoe George
Published: June 2006

A questionnaire sent to a number of clay mfgs. elicited the information: (1) better sagger cost system needed; carborundum and Na SiO are frequent constituents of the sagger body; (3) jaw crusher better than pan grog; (4) sagger containing 30 per cent carborundum and lasting 20 or more fires is economical.
NOTE ON THE ACID RESISTANCE OF ENAMELED COOKING UTENSILS1
Authors: Swesly B. T.
Published: June 2006

Apparent segregation of the constituents of an enamel under the influence of gravitation.—Experiments with trial pieces with poured samples, and with enameled ware of various mfgr's. showed that the surface of the layer of enamel which is uppermost during firing and cooling is readily attacked by acid, thus indicating, apparently, that the more soluble materials tend to rise to the top of the melt. It is therefore recommended that enameled kitchen utensils be fired in an inverted position. In the discussion by Bryan A. Rice a series of similar experiments are described using small shallow cups. Quantitative tests failed to show any difference in acid resistance and it is suggested that the author's results were due to the nature of the gases in contact with the enamel surface or to volatilization. In his reply the author accepts this explanation of his results.
NOTE ON COBALT STAIN IN WHITE WARE BODIES
Authors: Watts Arthur S.
Published: June 2006

Faulty methods of adding cobalt.—Cobalt oxide or directly added cobalt sulphate frequently causes a blue‐gray cast when the body is hard fired.

Correct preparations of stain from cobalt sulphate.—To 750 ounces of pure water add 15 ounces pure cobalt sulphate (CoSO4+ 7H2O) and stir until dissolved. Then add 7.5 ounces of carbonate of soda (Na2CO3) and stir thoroughly.

Adding stain to body.—Ball clay must be thoroughly blunged with body before adding stain. If used in a casting slip, add the stain as a part of the casting solution.

Proportions stain to body.—For a body containing 10 per cent ball clay add 75 ounces stain solution to each 1500 pounds body, i. e., ½ ounce stain for each 10 pounds body. For bodies with higher ball clay content increase the stain addition in the same ratio up to 15% ball clay.

Stain in glazes.—Add 10 ounces stain to each 100 pounds dry glaze batch when same is thoroughly wet in mill. For glaze high in lead, the amount of of stain required is increased.
THE VALUE OF AGEING THE TERRA COTTA BODY1
Authors: Clare R. L. , Long R. N.
Published: June 2006

It is shown that the terra cotta body when aged for a period of twelve days improves in plasticity, workability and strength. If the body is aged and subsequently repugged, still greater improvement is noted. This process is recommended as developing to the fullest extent the latent qualities of the body. The theory of this action seems to be a softening of the clay grains which with the retempering process results in a finer subdivision of the particles and a more intimate combmation of the clay and grog.
APPLlCATION OF ELECTRIC HEAT TO VITREOUS ENAMELING1
Authors: Barringer Lawrence E.
Published: June 2006

A two‐compartment open‐chamber furnace with separating door operated from the outside is described. The source of heat is an electric current passed through a nichrome resistor ribbon wound over refractory supports arranged along the sides of the furnace. The front or preheating compartment is operated at 300°C and the back or finishing compartment at 900°C, with automatic control. The advantages, compared with oil heating, are: rejections reduced from 25 per cent to zero; 50 per cent increase in output for same floor space; 47.4 per cent lower fuel cost; improved quality and uniformity; lower maintenance cost and greater ease of operation.
TESTING COKE OVEN REFRACTORIES1
Authors: Harvey F. A. , McGee E. N.
Published: June 2006

General Reluirements are stated for mat, bench walls, checker work, regenerator korbels, main flues, division walls, oven chambers and jamb blocks. The following Tests are described:—inspection, reheating tests on three qualities, bending test.

Requirements and specifications are discussed. The latter part ofthe paper deals with Apparent density and Permanent expansion. It is shown that the relation between them is a linear one and a chart is given. The average of thirty‐nine determinations gives an apparent density, for Western brick, 0.016 higher than for Pennsylvania brick, due to the fact that the Western ganister is slower to transform than the Eastern.