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

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

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