Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references.

The staghorn sculpin Leptocottus armatus is abundant in the Yaquina Bay estuary on the central Oregon coast and also occurs offshore in shallow water. A total of 560 L. armatus were collected at three locations in Yaquina Bay and between 7 and 11 kilometers offshore in depths of 40 to 80 meters. Staghorn sculpins were present in all areas where collections were made throughout the year except during the summer when most offshore sculpins moved into Yaquina Bay. Leptocottus armatus spawned primarily in the bay during the fall and early winter. The young fish remained in Yaquina Bay for about one year at which time they were about 12.0 cm in length. Subsequently, some of them moved offshore. Seventeen different species of parasites were collected from the 526 L. armatus examined. Genolinea laticauda was collected from the stomachs of 25.1% of the fish and had greater incidence and intensity in larger fish. Recruitment of immature forms began in April and the average life span was about seven months. The life cycle was most efficient in the lower estuary. Tubulovesicula lindbergi occurred in the stomachs of 50.8% of the fish and had greater incidence and intensity in small fish. Recruitment of immature individuals occurred all year, but was greatest in June. The life cycle was most efficient in the upper estuary. Podocotyle atomon was found in 42.6% of the fish and was most abundant in the larger fish. Bucephalopsis ozakii was collected in 38.8% of the L. armatus and was more abundant in large fish, as were larval tetraphyllidean cestodes which were present in 40.7% of the fish. These two parasites were found to be positively associated because they were both more likely to parasitize larger fish. Nematodes believed to be Contracaecum cornutum were found in ulcers in the stomach of 28.0% of the fish. This was the only parasite that was obviously pathogenic. Echinorhynchus gadi occurred in 47.4% of the fish. Immature worms were obtained all year, but only from fish in the upper estuary. Other parasites encountered were the protozoans Scyphidia sp., Trichodina sp. and Ceratomyxa sp.; the trematodes Gyrodactylus sp., Neopodocotyloides sinusaccus and Derogenes sp.; the nematode Contracaecum aduncum; a piscicolid leech; the copepod Acanthochondria rectangularis and the isopod Lironeca vulgaris. It was concluded that all the parasites of L. armatus could be acquired in Yaquina Bay, although it was more likely that the larval cestode was acquired offshore. The parasite data could not be used to determine movements of L. armatus in and out of Yaquina Bay, but the data were utilized to show that movements between the upper and lower estuary were not extensive. / Graduation date: 1973

Thesis (Ph. D.)--University of Michigan, 1926. / Cover title. Thesis note on label mounted on p. 427. Letterpress on versos facing the plates. "Reprinted from the Journal of Morphology and Physiology, vol. 43. no. 2, March, 1927." Bibliography: p. 478-480.

Thesis (PH. D.)--University of Michigan, 1926. / Cover-title. Thesis note on label mounted on p. 427. Letterpress on versos facing the plates. "Reprinted from the Journal of Morphology and Physiology, vol. 43. no. 2, March, 1927." Bibliography: p. 478-480.

The prickly sculpin, Cottus asper, is a polytypic species characteristically represented by very prickly, fresh-water spawning "inland" forms, and less prickly, brackish-water spawning "coastal" forms. Its widespread geographic distribution, pronounced phenotypic variability, and the effects of the contrasting environments in which it occurs are the subject of this investigation. A complete nomenclatural history and synonymy of the species for the period 1836-1936 is presented. Morphological evidence is interpreted in the light of field and laboratory studies of the migration and reproductive behavior. Differences found in distribution and intensity of body prickles (modified scales), geographical distribution, and migratory behavior, support the contention that the polytypy of "coastal" and "inland" forms of Cottus asper has a genetic basis. Other morphological evidence is equivocal in support of this interpretation. Differences in fin ray counts, e.g., pectoral rays, between "coastal" and "inland" forms are correlated positively with the presence or absence of salinity in the environment. However, it is not known whether such differences are the result of individual modifications induced by the local environment, or due to long term genetic fixation. Evidence from studies of closely-related species supports the interpretation that Cottus asper is a polytypic species which has become, and is in the process of becoming, modified into several characteristic genotypes. Evolution within this “asper species group" probably occurred in three stages, each correlated with past geologic history. During the first stage, perhaps in the Pliocene or Late Miocene, "coastal" and "inland" forms were derived from an ancestral marine cottid. The second stage, during the Pleistocene, was characterized by fragmentation of the gene pool of the "inland" form into a series of geographically isolated populations which have since evolved into valid species. The third stage, in Recent Time since the retreat of the Cordilleran glaciers, has occurred primarily within the northern representatives of the "coastal" form. At least two derivatives can now be distinguished within the "coastal" form. / Science, Faculty of / Zoology, Department of / Graduate

Long-term subae lal survival has been anecdotally noted in the staghorn sculpin, Leptocottus armatus. In this study, I quantified this phenomenon physiologically by examining the following parameters: standard metabolic rate and indications of reduced standard metabolic rate during subaerial exposure; capacity for and mechanism(s) of oxygen consumption in air; capacity for anaerobic production of lactate and/or ethanol; and blood pH. The staghorn sculpin appears well-suited for the subaerial exposure it experiences in nature. Mean subaerial survival time was 6 hours which would enable fish to survive intertidal stranding. Staghorns breathe air through well-supported gills and supplement depressed rates of subaerial aerobiosis by anaerobic production of lactic acid. Most remarkably, the staghorn sculpin may also substantially reduce minimal energy expenditure requirements during periods of hypoxia by reducing resting metabolic rate. / Graduation date: 1991

No description available.

The overall objective of this research project was to assess whether fish populations in areas of potato cultivation responded to changes in environmental conditions. An effects-based assessment was conducted in the ‘potato belt’ of northwestern New Brunswick in the Little River catchment. From 1999-2001, the health and performance of slimy sculpin (Cottus cognatus) was monitored in agricultural and forested sections of the river. In the fall of 1999 and 2000, agricultural sites had fewer young-of-the-year (YOY) sculpin than the forested region. Adult sculpin were larger in the agricultural region, but had significantly smaller gonads, and female sculpin had smaller livers, and fewer and smaller eggs than the forested region. By the fall of 2001, only female gonad size showed a difference from the forested region. These results were used to design a follow-up study designed to investigate the relative importance of environmental factors influencing sculpin responses. <br><br> The second study investigated the relative influence of temperature and sediment deposition on slimy sculpin populations across 20 sites on 19 streams in forested and agricultural catchments in northwestern New Brunswick. YOY sculpin were present at all forested sites, but only at 2 of 11 agricultural sites. There were no relationships between body size or density and sediment deposition in either the agricultural or forested regions, but sculpin density decreased and median YOY size increased with increasing temperatures. The variability in density of YOY sculpin at agricultural sites suggested that additional factors beyond temperature might be contributing to responses. <br><br> A secondary overall objective was to evaluate the slimy sculpin as a sentinel and indicator of site-specific conditions. Stable isotopes of muscle tissues showed little variability in isotopic signatures, and significant differences between adjacent sites. Passive integrated transponder (PIT) tags implanted in 112 adult sculpin showed that 75% of sculpin captured over 10 months moved less than 30m. Both isotopes and PIT tags suggested high spatial and temporal residency of slimy sculpin. <br><br> This PhD project showed biological impacts on sculpin populations residing in streams influenced by non-point source agricultural stressors, and provided support for the ability of the slimy sculpin to reflect local environmental conditions.

The mucus coat on the skin and gill of fishes serves a variety of protective functions including lubrication of the body surface, prevention of infection, and deterrence of parasites. Since mucus secretion in some teleosts appears to be controlled by the osmoregulatory hormones, prolactin and Cortisol, it was thought that the mucus coat may participate in teleost hydromineral balance. The primary objective of this study was to -examine the possible role of mucus in-osmoregulation of Leptocottus arma- tus Girard 1854 (Teleostei, Cottidae) and to relate these findings to the -endocrine control of mucus secretion. Whereas Leptocottus skin includes three types of secretory cells (eosinophilic granular, goblet, and cuticle-secreting cells) , the gill epithelium -has only goblet cells. Of ten cottid species examined histochemically, only seawater sculpins produce neutral mucins, while fresh water, seawater, and euryhaline species produce acidic mucins. Leptocottus primarily secretes a sialoglycoprotein, though sulphated mucins are present in gill goblet cells and the cuticle-secreting cells. The granular cells produce a tryptophan-rich basic protein. - Hypophysectomy or seawater adaptation reduce the number of gill goblet cells, compared to respective sham-operated or 5% seawater-acclimated controls. Ovine prolactin treatment of hypophysectomized fish prevented this decrease. In seawater-acclimated Leptocottus prolactin injections increase the number of gill mucus cells, while Cortisol injections of 5% "seawater-adapted fish had the opposite effect. The cuticle-secreting cells were most active in 5% seawater-adapted fish and this state was maintained by prolactin. A moderately active state was typical of seawater-adapted fish and this condition could be maintained by Cortisol or ovine growth hormone. The lowest activity of the cuticle-secreting cells occurred in hypophysectomized fish. Though prolactin and Cortisol appear to control the gill goblet cells and the cuticle-secreting cells, neither hy-pophysectomy nor treatment with prolactin or Cortisol significantly affected the skin goblet cells. The mucus coat appears incapable of reducing integumental permeability through steric interference of diffusion or through Donnan exclusion of ions from the mucus coat. Further, it is argued that enhancement of unstirred layers by mucus could not significantly affect hydromineral balance. Instead, alterations of the mucus coat with environmental salinity may be associated with the lubricating properties of mucus. Leptocottus mucus is a viscous non-newtonian fluid when concentrated but is an efficient lubricant when dilute. Seawater-adapted Leptocottus produce a more efficient lubricating mucus than do 5% seawater-acclimated fish; this effect appears to involve the cuticle-secreting cells. In an associated study I showed that the skin of the goby Gillichthys mirabilis participates actively in osmoregulation through extra-renal ion excretion. Thus the effects of prolactin and Cortisol may be primarily to control active transport in the skin. / Science, Faculty of / Zoology, Department of / Graduate

The study of the Utah sculpin in Logan River was based on 801 specimens collected during 1949 to March 1951. Numbers of fish examined for various catagories of the study wares length-frequency, 495; aging by vertebrae, 407; length-weight relationship, 601; and food habits, 275. Fish were collected by use of an electric shocking machine generating 600 watts and 220 volts. Numbers of fish occurred as high as 150 per tenth mile of stream. Preferred habitats occurred in areas of coarse gravel and small rocks. Vertebrae dissected from the fish were used in age determination. Length-frequency proved to be a general correlation to the aging technique. Fish were difficult to sex by external observation except during the breeding season. Relationship between standard length and weight is described by the following formula: W = 4.236 X 10-4 L2•900 The coefficient of condition (K) increased with length up to 60 millimeters in standard length and decreased in length in fish ranging from 60 to 125 millimeters in standard length. The greatest variation in K occurred in fish below 50 millimeters in length. The factor for converting total length to standard length as determined from 601 specimens between 24 and 112 millimeters. standard length was 0.812. The factor for converting standard length to total length for the same fish was 1.232. The bulk of the diet consisted almost entirely of aquatic insects. Most of the aquatic insects were diptera. Ephemeroptera, plecoptera, and trichoptera were consumed in almost equal numbers. Food availability and preference were determined from bottom samples of the river. Competition for food is minimized somewhat by the fact that the sculpin is a bottom feeder and the trout is primarily a surface feeder. Predation of trout eggs by the sculpin was almost non-existent.