There are about twelve species of cottid fishes which inhabit tidepools at Port Renfrew, Vancouver Island, British Columbia. Two of the more abundant species, Ollgocottus maculosus (Girard) and Oligocottus snyderi (Greeley), display vertically zoned microdistrlbutions. Ollgocottus maculosus is very abundant in the upper tidepools while O. snyderi occurs only in lower tidepools. A comparative study of the ecology of these species was made to assess the role of environmental parameters in determining their microdistrlbutions. Environmental parameters considered were depth, substrate and cover, food, interspecific interactions, salinity and temperature. The relationships between the field data, behavioral and physiological laboratory experiments were used to assess the role of the various factors. The results indicate that the influence of the environmental factors considered varied with species. The tide-pool distribution of O. maculosus is influenced but not wholly determined by its high tide depth preferences. The high tide depth preferences of O. snyderi is not related to its tidepool distribution. The interspecific interactions between the two fish appear to affect the depth distribution of O. maculosus while that of O. snyderi is not affected. Substrate-cover affinities of O. maculosus do not limit the occurrence of this species to tidepools or tidepool areas of a specific type, whereas Ollgocottus snyderi is rigidly bound to pools with dense macrophytic cover. This factor, however, does not account for the absence of O. snyderi from upper tidepools with dense vegetal cover. Interspecific interactions between the two fish do not appear to grossly influence their respective microhabitat preferences. The possibility of interspecific competition for food appears remote as both species, though feeding on the same basic items, display no sign of "interactive segregation" or "separation of food spectra" as evidenced in competitive situations among some other species of fishes. However, O. maculosus does consume a greater variety of food. Field observations indicate the common occurrence of major food items irrespective of season or vertical location of the tidepools. For both Ollgocottus maculosus and O. snyderi, resistance to low salinities of the magnitude encountered in tidepools is substantial enough to allow either species to survive most hyposaline conditions found within the intertidal zone. However, the occurrence of O. maculosus beyond the upper boundary of the intertidal may be limited by hyposaline extremes. Ollgocottus snyderi generally shows a lesser resistance to low salinities than does O. maculosus. The tidepool distribution of O. maculosus is not limited by tidepool temperatures as this species displays a relative resistance and tolerance to temperature extremes at least as great as those occurring in the highest tidepools. Ollgocottus snyderi, however, is unable to tolerate and/or resist extreme temperatures occurring in upper tidepools and is therefore limited to lower pools. It appears that the tidepool distribution of O. maculosus is not dominated by any single factor with the possible exception of turbulence (open, exposed areas) and population density. Thus it is a versatile species, behaviorally as well as physiologically, and is able to exploit virtually all tide-pools in the intertidal zone. The tidepool distribution of O. snyderi is affected by substrate and cover as well as temperature. Of these, temperature appears to be the limiting factor within the intertidal zone since O. snyderi cannot survive in upper tidepools which are characterized by more extreme and unstable temperatures. / Science, Faculty of / Zoology, Department of / Graduate

The study was concerned first of all with the distribution pattern at low tide of Oligocottus maculosus Girard and other cottid fishes inhabiting tidepools on the west coast of Vancouver Island, B.C. Five species (O. maculosus, G. remensis, Clinocottus acuticeps, C. einbryum and C. globiceps) have their centers of distribution in the intertidal zone. Seven species (Hemilepidotus hernilepidotus, Artedius lateralis, A. fenestralis, Ascelichthys rhodorus, O. snyderi, Enophrys bison and Leptocottus armatus) inhabit tidepools but are most abundant in the subtidal zone. O. maculosus is the most abundant and widely distributed tide-pool cottid in the intertidal zone. Only three other species (C. acuticeps, C. embryum and C. globiceps) regularly inhabit tidepools above LLHW (lowest lower high water). The primary environmental factor correlated with the distribution of O. maculosus is exposure to wave action. In exposed transects this species is restricted to the upper intertidal zone, while in sheltered transects it inhabits tidepools throughout the intertidal zone. Observations show that O. maculosus responds to water turbulence by retreating to cover. It is concluded that to inhabit a given tidcpool O. maculosus must have a minimum period of low turbulent conditions. This species has 'capitalized' on the tidcpool habitat to invade the open coast environment. The study's second concern was to determine the fidelity of individual O. maculosus to the tidcpool in which they are found. O. maculosus shows fidelity to specific tidepools and will return to these pools when displaced from them. The results indicate that the navigational ability of O. maculosus is not solely dependent upon familiarity .with geographical features of the intertidal zone. It is suggested that homing behavior functions as a mechanism stabilizing the spatial distribution of this species. Thirdly, the study was concerned with determining what factors affect the field activity such as feeding and spawning of O. maculosus, and a comparison of its field activity to that under controlled conditions. In the natural habitat its activity is dependent primarily upon such factors as turbulence, temperature and light. Field observations on feeding behavior support Morris1 (I960) conclusion, drawn from physiological studies, that approximately the 16°C isotherm is the limiting environmental factor in the southward distribution of this species. Under constant conditions O. maculosus exhibits a tidal rhythm of locomotor activity. The characteristics of the rhythm indicate that it is entrained directly by the tide. Hydrostatic pressure is suggested as the possible synchronizer. The rhythm is not directly related to the field activity of O. maculosus. It is concluded that it represents the coupling of an avoidance or escape response to a biological clock. Such a mechanism would function with, and be partially responsible for, the homing behavior. / Science, Faculty of / Zoology, Department of / Graduate

A detailed morphological study has been made between two apparently closely related species of the cottid genus Myoxocephalus (Steller) Tilesius, Myoxocephalus polyacanthocephalus Pallas and Myoxocephalus jaok (Cuvier and Valenciennes), Large series of both species were examined. Coloration was found to be one of the major differences, between the two species. They were also found to differ in the degree of sexual dimorphism. Sguamation, the lateral line system, and osteology were examined by clearing and staining. The scales and lateral line ossicles were found to be morphologically distinct. The osteology was essentially similar in both species, the only major difference being the loss of the third preopercular spine in M. jaok. The musculature of head and caudal regions was examined in detail but no significant differences were encountered. A preliminary examination of the 1 muscle proteins by means of starch-gel electrophoresis was also undertaken. Distinct differences in the mobilities of several protein bands were encountered. Analyses of meristic characters revealed large variation, and almost complete range overlap between the two species. The modes of several of these counts however, were different. Morphometric characters indicated close similarity and of the 32 measurements taken and the 992 combinations compared, only two yielded significant differences„ These were depth of caudal peduncle against length of anal fin base and depth of caudal peduncle against length of second dorsal fin base. / Science, Faculty of / Zoology, Department of / Graduate

Gymnocanthus is a cottid genus containing six species which inhabit the North Pacific, Arctic, and North Atlantic Oceans. The genus is characterized by edentulous palatines and prevomer, granulations on the nape, scales restricted to axillary prickles, and an elongate, multicusped pre-opercular spine. Six species (Gymnocanthus detrisus, galeatus, herzensteini, intermedius, pistilliger, and tricuspis) are recognized. These are identified by their different meristic characters, interorbital width, cleithral spine development, presence or absence of subpectoral dermal pistillae in males, and other features. No subspecies are recognized. Synonymies, descriptions, colour, maximum size, etymology, and range are given for each species. The key, used in conjunction with diagrams showing several diagnostic characters is useful for identifying specimens to at least 60 mm. Though some morphometric characters (head length, interorbital width and others) are significantly different between some species because of their great variability they are seldom taxonomically useful. Superimposed on this variability is strongly developed sexual dimorphism, males possessing significantly longer dorsal and pelvic fins than females. Other sexually dimorphic characters include the roughening of the inner edge of the pectoral rays, the brighter colours, and the penis in males of all species, and the axillary pistils in males of Gymnocanthus pistilliger and G. intermedius. Though its systematic position is obscure, Gymnocanthus probably arose in the Aleutian Islands, dispersing westward by planktonic larvae, and eastward by migration along the shallow Aleutian shelf. Gymnocanthus evolved in two directions, one forming a group of three smaller species (G. tricuspis, pistilliger, and intermedius) showing great sexual dimorphism and low meristic characters, the other, a group of larger species (G. galeatus, detrisus, and herzensteini) with lesser developed dimorphism and high meristic characters. Possible origins for the two lines are discussed. For lack of comparative information, the systematic position of Gymnocanthus within the family Cottidae is not examined in the present paper. To facilitate future intergeneric comparative studies, the osteology and cephalic lateral line system is described for the genus. No profound osteological differences between species exist; superficial differences between species reflect those diagnostic specific differences ( i.e. interorbital width, head length) previously noted. Pore number and distribution in the cephalic lateral line system tend to differ between species, but are too variable to be of taxonomic use. Breeding seasons are inferred from presence of young and from gonad maturity. G. herzensteini is a winter breeder, G. galeatus and G. pistilliger breed in spring, while G. tricuspis breeds in late summer. Data are not available for G. detrisus and G. intermedius. In three species examined (G. tricuspis, galeatus, and pistilliger) fish live to four years or more. Females grow more quickly than males, especially after two years. G. tricuspis has a wider salinity range and lower temperature tolerance than have the other species, permitting it to survive in Arctic waters. Ecological separation of the remaining species is not so clear, though G. pistilliger and G. intermedius seem to inhabit shallower water as adults than do G. galeatus and G. herzenstein. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.A.)--Oregon, Dept. of Biology Vita Bibliography: l. 46-50

The purpose of this study was to compare the systematic relationships within the genus Myoxocephalus (Pisces; Cottidae) suggested by separate conventional morphological and "bio-chemical"=protein evidence and to compare the effects of numerical and conventional systematic analyses of this evidence on the relationships. About 5000 specimens representing 13 nominal species of the genus Myoxocephalus provided the source for morphological investigation. An additional 157 fresh-frozen specimens representing 11 nominal species were used in the determination of biochemical differences. Protein data consisted of electrophoretic characteristics of muscle protein, malic dehydrogenase, and lactic dehydrogenase. No sexual variation in banding patterns of any of the characters employed was detected. In each species examined the myogen pattern was constant and unique. In only two nominal species were samples obtained from wide geographic range. One of these (M. scorpioides) had a constant pattern, the other, M. "M. scorpius" revealed the presence of two species types within the currently recognized taxon. There were two electrophoretic patterns in the malic dehydrogenase isozymes, 10 species possessed one pattern, two the second. Eleven species had identical isozyme patterns of lactic dehydrogenase. One other species (M. scorpioides) was biphasic. Within the 7 meristic characters examined, both latitudinal and longitudinal clines were exhibited. Latitudinal clines generally increased northward. Longitudinal trends increased eastward across the Arctic of North America, while in the transpacific species values increased westward. In cases where there was a response in the number of pectoral rays, it was in a direction opposite to the response in the other meristic features. Meristic characters were rich in differences between species. Morphological data excluding morphometric characters were derived from 20 major conventional features as well as from squamation, cephalic lateral line system, lateral line ossicles, olfactory rosettes, and the coiling pattern of the gut, all of them features not previously used in systematic studies of this genus. Twenty body features were measured and gave rise to 190 character combinations. When analyzed these did not yield any natural groupings. Separate phenetic dendrograms based on "biochemical" and morphological data were derived as well as dendrograms based on numerical taxonomic analyses of biochemical, morphological and the combined data. No similarities were exhibited upon comparison of the numerical analyses of "biochemical" and morphological data. However, patterns of relationships from both "biochemical" and morphological sources using the conventional phenetic treatment were similar. The conventional and numerical treatments of the morphological data yielded almost identical patterns of relationship between the species. Analyses of the "biochemical" data using the same two approaches produced completely different results. Speculations are included on the probable sources of the differences arising from the latter comparison. A new diagnosis of the genus Myoxocephalus was given as well as a synopsis of the species attributed to it. Two unrecognized species were revealed through the analysis. / Science, Faculty of / Zoology, Department of / Graduate

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

Chapter 1. Fast-starts are used by most fish species in order to capture prey and escape predators. An introduction to this mode of fish locomotion and the structure and function of the muscle powering swimming movements, is given. Temperature has the potential to alter fast-start behaviour at various levels of organisation ranging from the whole animal to the molecular and can act over time scales extending from the immediate to the evolutionary. The thermal dependence of fast-start performance is discussed. Chapter 2. The effects of acclimation and acute temperature on the kinematics of the escape response in two species of maidne Cottidae, the short-horn sculpin (Myoxocephalus scorpius L.) and the long-spined sea scorpion (Taurulus bubalis Euphr.) were examined. Hypotheses were formulated based on relevant studies and the natural history of the fish to test the idea that seasonal temperature acclimation conferred a fitness advantage and to examine whether acclimation responses were constant through development. Chapter 3. The effect of seasonal thermal acclimation on the in vivo strain and power output of the fast muscle fibres during escape responses in the short- horn sculpin was examined. Chapter 4. The kinematics, in vivo muscle action, power output and energetics of escape and prey capture responses in the short-horn sculpin are discussed. Fast-starts were filmed using high speed video synchronised with sonomicrometry and EMG. The in vivo muscle strain and activation recordings were abstracted for use in work loop experiments. Changes in the metabolic substrates following work loops from the two different types of fast-starts were analysed using high performance liquid chromatography (HPLC). Chapter 5 The velocity of the wave of curvature passing down the fish and the power requirements during fast-start escape responses were calculated non-invasively. This was carried out on both cottid species acclimated to 5 and 15 ° and filmed using high speed cinematography at 0.8, 5.0, 15.0 and 20.0 °. The power requirements for the contralateral contraction were 20 W. kg-1 muscle in 5 °-acclimated fish escaping at 5 ° and 58 W. kg-1 muscle in 15 °-acclimated fish swimming at 15 °. Comparative values of power output measured from work loop experiments in Chapter 3 were 33 and 66 W.kg-1 respectively.

An estimated 90% of resident sculpin (Cottus asper and C. aleuticus) were impacted by a spill of 45,000 litres of sodium hydroxide, which occurred on the Cheakamus River, British Columbia on August 5, 2005. This study examined sculpin biology, life history, how sculpins are recovering from the impact, and whether they are re-entering the Cheakamus River from the adjacent Squamish and Mamquam Rivers. Sculpins were sampled in the three river systems via minnow trapping and electrofishing. Morphometric data were recorded and fin clips were taken as deoxyribonucleic acid vouchers to validate field species identification and to determine population distinctiveness among the three systems. Populations were not distinct, suggesting recolonization from other rivers is occurring. The data show sculpins will undergo seasonal downstream spawning migrations and also suggest sculpins are opportunistic habitat colonizers. This research bears useful implications for the adaptive management, recovery, and sustainability of sculpins in the Cheakamus River.

Underyearling Bear Lake sculpin exhibit a diel pattern of vertical migration throughout the pelagic region of Bear Lake (Utah-Idaho) until they are approximately 22 mm standard length. Individuals move from the bottom of the lake (5° C) during the day into the water column (13-16° C) at night. The migration, however, is not related to feeding. Although the dominant copepod in the water column, Epischura nevadensis, do undergo a similar diel vertical migration, stomach analysis of juvenile sculpin captured by trawling shows that they do not feed in the water column. Instead, from July through October, their diet is dominated (70-93%) by benthic copepods and ostracods. Also, gut fullness of sculpin increases through the daylight period and decreases through the night, reaching minimum levels just before the dawn descent. Furthermore, feeding trials conducted in the laboratory show that juvenile sculpin feed most efficiently at light intensities found on the bottom (30-60m) of Bear Lake during the day. Feeding rate coefficients increase markedly from 1013 photons m-2S-1 until peaking at intermediate intensities of 1016 photons m-2S-1 and then decline at higher light levels. Although they do not migrate to feed, the movement into the warmer water appears to increase the sculpin's digestion rate, thereby allowing continued feeding during the day. This supports the hypothesis that diel vertical migration in Bear Lake sculpin is a thermoregulatory strategy that increases growth rate.