Cottus Asper Research Articles

The effects of hatchery and wild ancestry and experience on the relative ability of steelhead trout fry (Oncorhynchus mykiss) to avoid a benthic predator

Differences in selection regimes between hatchery and natural environments and environmental stimuli, among other factors, have the potential to cause differences in predator avoidance ability between hatchery and wild steelhead trout fry (Oncorhynchus mykiss). In two separate laboratory experiments, fry raised from eggs of wild Quinault River steelhead trout survived predation by prickly sculpin (Cottus asper) significantly better than size-matched offspring of a locally derived hatchery population, which were reared under similar conditions. Wild fry also survived predation better than hatchery fry in natural stream enclosures over a 3-day test period. Experience, in the form of 50-min visual exposure to sculpin predation on "sacrificial" steelhead trout, improved the ability of fry from both populations to avoid predation by sculpin. Wild-experienced fry were eaten in the fewest number of trials followed by wild-naive, hatchery-experienced, and hatchery-naive fry. The results of this study are consistent with the hypothesis that innate predator avoidance ability has been negatively altered through domestication and that attempts to condition hatchery-reared steelhead to avoid predators may be limited for domesticated populations.

Proliferative kidney disease and Sphaerospora oncorhynchi in wild-caught salmonids from the Puntledge River system, Vancouver Island, British Columbia

Proliferative kidney disease (PKD), caused by the PKX myxosporean, was observed in kokanee salmon (non-anadromous sockeye salmon) (Oncorhynchus nerka) and chinook salmon (O. tshawytscha) collected from the Puntledge River, Vancouver Island, British Columbia in July 1993. This is the first report of a natural infection of PKX in either captive or wild sockeye salmon. All 14 underyearling kokanee salmon and the one underyearling chinook salmon exhibited numerous PKX organisms and associated chronic inflammation in the renal interstitium. Thirty-eight percent of sexually mature kokanee salmon collected in the autumn of 1993 from Comox Lake (which drains into the Puntledge River) were infected with Sphaerospora oncorhynchi, Kent, Whitaker and Margolis, 1993 in the renal tubules, while immature cutthroat trout (O. clarki) and coho salmon (O. kisutch) from the same collection did not exhibit myxosporean spores in the kidney. The kidneys of threespine stickleback (Gasterosteus aculeatus) and prickly sculpin (Cottus asper) collected from the Puntledge River during the summer were all infected with a Myxobilatus sp., but no organisms suggestive of PKX or Sphaerospora were observed. This study further supports the hypothesis that PKX is a developmental stage of S. oncorhynchi, which may sporulate only in sexually mature salmonids.

Horizontal and vertical movements of telemetered rainbow trout (Oncorhynchus mykiss) in Lake Washington

In summer and fall 1989, six rainbow trout (Oncorhynchus mykiss) were tracked in Lake Washington with ultrasonic transmitters for a total of 349 h to determine their movements in relation to the distribution of possible prey species. The trout moved primarily in the nearshore area at an average velocity of 12.4 cm/s (~ 0.25–0.3 body lengths/s). Five of the six fish made one more rapid (>1 body lengths/s) excursion across the lake, then continued moving in the nearshore zone. The trout were generally inactive, staying close (<50 m) to shore at night, and became more active near dawn; however, the highest average velocities were at dusk. They spent over 90% of their time in the top 3 m of the water column and 10% in brief (2 min), shallow (mean 6.6 m) dives. Dives occurred most frequently at dawn and during the day (0.8/h), less often near dusk (0.5/h), and seldom at night (0.1/h). The depth distribution and movement patterns suggest that the trout were feeding on Daphnia pulicaria during the day, in both nearshore and offshore areas, supplementing this diet with nearshore fishes such as prickly sculpins (Cottus asper). Predation on pelagic planktivores (longfin smelt, Spirinchus thaleichthyes, and juvenile sockeye salmon, Oncorhynchus nerka) was unlikely because the trout were primarily found nearshore and near the surface, whereas the planktivores are primarily offshore and closer to the bottom.

Comparative ecology of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River, California

We documented species' distributions, size structure of populations, abundance in mainstem and tributary streams, habitat use, and diets of prickly sculpin, Cottus asper, and coastrange sculpin, C. aleuticus, in the Eel River drainage of California, to determine the processes allowing coexistence of these very similar fishes. We observed prickly sculpins at 43 sites and coastrange sculpins at 34. The species co-occurred at 26 sites. Young-of-year coastrange sculpins were only observed within 42 km of the ocean, but young-of-year prickly sculpins were present throughout the species range. Mean, maximum, and minimum lengths of coastrange sculpins were positively correlated with distance from the ocean but no significant relationships were found for prickly sculpins. Absolute abundance of both species was highest in mainstem habitat (prickly sculpins = 0.6 sculpins m−2 and coastrange sculpins = 0.4 sculpins m−2) . Tributary densities of both species tended to be less than 0.1 sculpins m−2. The species inhabited very similar habitats and had very similar diets. Coastrange sculpin populations in upstream areas were maintained by immigration from downstream areas in contrast with prickly sculpin populations that produced young-of-year fish throughout their range. Densities were probably not high enough for interspecific interactions to be important. The factors limiting the upstream distribution of the species may include high water temperatures, stability of the stream bed, and behavior of the fish. In the past, the range of sculpins within the Eel River drainage probably fluctuated with changing physical conditions. Recent introductions of exotic species that compete with and prey upon sculpins, and ongoing human activities in the drainage could result in major reductions in the distribution and abundance of one or both species.

Uptake of Selected Organochlorine Contaminants in Fishes Resident in the Fraser River Estuary, Vancouver, British Columbia

Abstract Starry flounders, prickly sculpins and other resident fishes were captured in the Lower Fraser River in the summers of 1987, 1988 and 1989. Control fish were taken from the estuary of the uncontaminated Homathko River on the B.C. coast in 1987 and 1988. The fish were analysed for chlorophenols, chloroguaiacols and PCBs. The residues most commonly detected were PCBs, tetra-and pentachlorophenol. Fish from the Main Arm contained PCBs that resembled Arochlor 1248 whereas those from the North Arm contained PCBs that resembled a mixture of Arochlors 1254 and 1260. Chloroguaiacol uptake was greater in flounders than in other species. Although PCBs appear to have declined markedly in the Lower Fraser from values published in the early 1970s, there is a need to measure the coplanar fraction to understand their toxic significance to the food chain. Tetra- and pentachlorophenol have declined following a change by industry to the use of alternative sapstain prevention treatments.

Feeding of Predaceous Fishes on Out-Migrating Juvenile Salmonids in John Day Reservoir, Columbia River

Diets of northern squawfish Ptychocheilus oregonensis, smallmouth bass Micropterus dolomieu, walleye Stizostedion vitreum, and channel catfish Ictalurus punctatus from John Day Reservoir were examined to determine the extent of predation on juvenile salmonids during seaward migrations of the salmonids during April–August 1983–1986. Juvenile Pacific salmon Oncorhynchus spp. and steelhead O. mykiss were the most important food group (by weight) of northern squawfish – about 67% – but made up smaller proportions of the food of the other predators: channel catfish, 33%; walleyes, 14%; smallmouth bass, 4%. Seasonal changes in diets indicated that northern squawfish preferred juvenile salmonids in May and August (generally the peak period of salmonid out-migration), and switched to prickly sculpin Cottus asper when numbers of juvenile salmonids declined; walleyes and smallmouth bass showed a preference only for prickly sculpin among the prey fishes analyzed. As judged by dietary composition and prey selectivity, the northern squawfish was the major fish predator on juvenile salmonids in the reservoir; channel catfish also were important predators in the upper reservoir in spring. Walleyes and smallmouth bass were much less important predators on salmonids, and appeared to select subyearling chinook salmon only in August when the distribution of this prey overlapped with that of the predators. Size-selective predation by northern squawfish may also play an important role in reducing survival of the smaller individuals within each run of out-migrating juvenile salmonids.

Seasonal and Diel Food Habits of Rainbow Trout Stocked as Juveniles in Lake Washington

Abstract I examined food habits of rainbow trout Oncorhynchus mykiss in Lake Washington, Washington, for relationships to the spatial and temporal distribution of their prey. Rainbow trout smaller than 250 mm (fork length) ate primarily Daphnia pulicaria during summer and autumn; larger fish were piscivorous throughout the year. Longfin smelt Spirinchus thaleichthys made up the largest fraction of fish prey in the diet of rainbow trout from the nearshore zone during autumn and winter, whereas prickly sculpin Cottus asper (in 1984) and yellow perch Perca flavescens (in 1985) were most important in spring and summer. Rainbow trout in the offshore zone (>15 m deep) ate mostly longfin smelt in spring and summer. Longfin smelt exhibited a 2-year cycle of abundance that appeared to influence the feeding habits of rainbow trout. During 1984, the adult longfin smelt population was large and provided the major prey of rainbow trout. When adult longfin smelt were less abundant during the 1985 winter, the fish fract...

Variation in Capture Efficiency of a Beach Seine for Small Fishes

We determined the capture efficiency of a beach seine as a means of improving abundance estimates of small fishes in littoral areas. Capture efficiency for 14 taxa (individual species or species groups) was determined by seining within an enclosure at night over fine and coarse substrates in the John Day Reservoir, Oregon–Washington. Mean efficiency ranged from 12% for prickly sculpin Cottus asper captured over coarse substrates to 96% for peamouth Mylocheilus caurinus captured over fine substrates. Mean capture efficiency for a taxon (genus or species) was generally higher over fine substrates than over coarse substrates, although mean capture efficiencies over fine substrates were significantly greater for only 3 of 10 taxa. Capture efficiency generally was not influenced by fish density or by water temperature (range, 8–26°C). Conclusions about the relative abundance of taxa captured by seining can change substantially after capture efficiencies are taken into account.

Effects of discharge fluctuation and the addition of fine sediment on stream fish and macroinvertebrates below a water-filtration facility

A small, coastal stream in the San Francisco Bay area of California, USA, received the discharges from a drinking-water filtration plant. Two types of discharges were present. Discharges from filter backwashing were 3–4 times base stream flow, occurred 10–60 times per day, contained fine sediments, and each lasted about 10 min. The other discharge was a large, steady flow of relatively sediment-free water from occasional overflow of the delivery aqueduct which generally lasted several hours a day. Samples of invertebrates from natural substrates had significantly fewer taxa and lower density at the two stations below the backwash than at the two above. However, when stable artificial substrates were used, there were no significant differences among all four stations. The aqueduct apparently had no effect because the. invertebrate community at the station upstream of the backwash but downstream of the aqueduct was statistically similar to the station above the aqueduct. To test for acute toxicity, we exposed additional artificial substrates to short-term simulated backwash conditions. These exposures had no effect on invertebrate density or drift. Three-spine stickleback (Gasterosteus aculeatus) populations were also significantly reduced at the two downstream stations and were made up mostly of larger, adult fish. Prickly sculpins (Cottus asper), restricted to the most downstream station, were emaciated and had poor growth, probably as a result of scarce benthic food organisms. Artificial redds with eggs of rainbow trout (Salmo gairdneri) had significantly lower survival at two stations below the plant backwash (30.7% and 41.8%) than at the one above it (61.4%). Hatchery rainbow trout held in cages below the treatment plant from 7 to 37 days survived and continued to feed. Thus, the major effect of the water treatment plant on fish and invertebrates probably was not from acute toxicity in the discharges or the occasionally large discharge of clean water from the aqueduct, but was from the fluctuating backwash flows containing fine sediment that displaced small fish downstream and created unstable benthic substrates for invertebrates. The filter plant that we studied is a direct-feed type (that is, no sedimentation before filtration). These generally require greater frequencies of backwashing than do conventional plants and may therefore have greater biological impacts. Direct-feed plants are becoming increasingly popular throughout the world, for the most part because they are cheaper to build and operate. But if the associated biological problems are mitigated, then the cost savings of direct-feed compared to conventional plants may be lost.

A Methodology for Estimating Area Fished for Baited Hooks and Traps Along a Ground Line

The methodology that estimates area fished for baited hooks or traps involves experimental fishing of strings of baited hooks or traps at different spacing along a ground line. This methodology enables expansion of catch per effort to a population estimate, when other methods may be impracticable. Experimentation and estimation procedures are given and the method is applied to data for prickly sculpin (Cottus asper), halibut (Hippoglossus stenolepis), and sablefish (Anoplopoma fimbria).Key words: baited hook, baited trap, stock assessment, fish density, longline, estimate

Report of the metacestode of Paradilepis simoni Rausch, 1949 (Cyclophyllidea: Dilepidae) from fish in British Columbia

Larval stages of tapeworms were found encysted in the livers of the following fish: 77% of 87 Oncorhynchus nerka (Walbaum), kokanee; 22% of 111 Salmo gairdneri (Richardson), rainbow trout; 13% of 113 Ptychocheilus oregonensis (Richardson), northern squawfish; 3% of 98 Prosopium williamsoni (Girard), mountain whitefish; and 2% of 85 Cottus asper (Richardson), prickly sculpin. The metacestodes were identified to be that of Paradilepis simoni from the number, size, and shape of the rostellar hooks.

Aspects of the ecology of the prickly sculpin,Cottus asper Richardson, a persistent native species in Clear Lake, Lake County, California

The biology of the prickly sculpin was investigated in Clear Lake, Lake County, California in order to determine how it has persisted in the face of introductions of numerous exotic species when most other native species have declined in abundance or have become extinct. Sculpins over 15 mm SL inhabited all types of benthic habitats in the lake, while post larval sculpins were pelagic when the postlarvae of exotic species were absent. The feeding ecology of sculpins was distinct from the other fishes in the lake in that they fed largely on amphipods and chironomid midge larvae regardless of the time of year, time of day, or habitat. Sculpins were uncommon in the stomachs of piscivorous fishes, except juvenile largemouth bass (Micropterus salmoides). It is concluded that prickly sculpins have persisted in Clear Lake in part because they are ecologically distinct from the exotic species and are not preyed upon by them to any great extent, and in part because they have managed to survive other man-related perturbations of this ecosystem.

The Lake Washington Ecosystem: The Perspective from the Fish Community Production and Forage Base

In Lake Washington, fish production through detritus-based food chains is substantially greater than fish production through the grazing food chain. The lack of significant grazing by fish on the zooplankton is a consequence of both piscivore predation and conditions in the planktivore spawning environment. At low planktivore abundance, squawfish may switch to benthos feeding, exploiting the abundant prickly sculpin. At high planktivore abundance, squawfish feed more heavily on planktivores. Thus, even when reproductive success of planktivores is good, swamping of the squawfish population does not occur and depensatory mortality due to squawfish predation prevents planktivore abundance from increasing to the point where zooplankton resource depletion would occur. Benthic–littoral species are vulnerable to predation essentially only as larva and juveniles. They avoid predation by occupying littoral and epibenthic refugia. Recruitment to the adult population from these refugia may be sufficient to account for the greater rate of benthos exploitation by fish relative to the rate of zooplankton exploitation by fish. Neomysis is an important component of the Lake Washington fish production, since potentially Neomysis is a regulating agent on the zooplankton, and reduction in Neomysis predation on zooplankton, due to decreasing abundance and a deeper vertical distribution, may be partly responsible for the recent reappearance of Daphnia. The response of the fish community to trophic changes in Lake Washington has been slight. No consistent trends in the growth of fish utilizing zooplankton were observed. However, annual growth increments of consumers utilizing the benthic detrital food chain have declined with sewage diversion. The insights gained from analyzing the Lake Washington fish community structure and the Lake Washington carbon budget corroborate the above response of the fish community to trophic changes. Planktivores are predator-controlled and not able to deplete zooplankton resources, and thus would be insensitive to alterations in standing crop of zooplankton. On the other hand, benthic–littoral fish are more resource-limited and would be expected to respond to alterations in their forage base. Key words: ecosystem, fish, production, Lake Washington, eutrophication, predation

Spawning and Fecundity of Seven Species of Northwest American Cottus

Spawning and fecundity of seven species of Cottus from the northwestern United States are discussed. These cottids spawn in the April-May period. They generally mature at age two; Cottus asper, however, matures at age three.

Diel Limnetic Occurrence of Young Cottus asper in Two British Columbia Lakes

not available

Spawning Habits and Morphological Variation in the Coastrange Sculpin, Cottus Aleuticus, and the Prickly Sculpin, Cottus Asper

Transactions of the American Fisheries SocietyVolume 97, Issue 1 p. 46-48 Short Papers and Notes Spawning Habits and Morphological Variation in the Coastrange Sculpin, Cottus Aleuticus, and the Prickly Sculpin, Cottus Asper William O. McLarney, William O. McLarney Department Wildlife and Fisheries, School of Natural Resources, Ann Arbor, Michigan, USASearch for more papers by this author William O. McLarney, William O. McLarney Department Wildlife and Fisheries, School of Natural Resources, Ann Arbor, Michigan, USASearch for more papers by this author First published: January 1968 https://doi.org/10.1577/1548-8659(1968)97[46:SHAMVI]2.0.CO;2Citations: 4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume97, Issue1January 1968Pages 46-48 RelatedInformation

THE EFFECT OF SALINITY ON THE IODINE METABOLISM OF COASTAL AND INLAND PRICKLY SCULPINS, COTTUS ASPER RICHARDSON

The lower mainland waterways of British Columbia are inhabited by two races of prickly sculpin, Cottus asper. The "coastal" race, which has a generally smooth skin, lives in the lower part of the rivers or estuaries and spends at least part of its life (particularly during the spawning season) under tidal conditions. The "inland" race, which displays a marked dermal "prickling", is confined entirely to freshwater, where it is found in scattered, more or less isolated populations, In freshwater the thyroid glands of both races are relatively quiescent, but with increasing salinity, particularly in a hyperosmotic environment, there is a marked increase in the uptake of tracer iodine by the thyroid and an elevation in the levels of circulating hormone. The inland fish have a greater ability than do the coastal fish to retain injected iodides in freshwater; in seawater the thyroids of the inland fish appear to be more active than do those of the coastal forms. The findings indicate a genetic divergence resulting in a relatively greater capacity of the inland fish to retain electrolytes.

A Case of "Schooling" Behavior in the Prickly Sculpin, Cottus asper Richardson

A Case of "Schooling" Behavior in the Prickly Sculpin, Cottus asper Richardson

Distribution and Taxonomy of Fishes in the Mackenzie Drainage of British Columbia

New and previously published records are listed for 28 species of freshwater fishes in tributaries of the Mackenzie River in northern British Columbia. Distribution patterns are discussed for all species reaching the continental divide at the Peace River headwaters; some are restricted to one or other side, but 17 species are common to the Peace and Fraser Rivers, suggesting that mountain ranges have served as a check but not an insurmountable obstacle to postglacial expansion. Five species indigenous to the Pacific slope—Catostomus macrocheilus, Richardsonius balteatus, Ptychocheilus oregonense, Mylocheilus caurinum, and Cottus asper—have evidently penetrated to the Peace River in comparatively recent times. Three species—the flathead chub Platygobio gracilis, the trout-perch Percopsis omiscomaycus, and the spoon-head sculpin Cottus ricei—have not previously been recorded from the province. Evidence is presented that subspecific distinctions are invalid in Couesius plumbeus (Agassiz) and Lota lota (Linnaeus). Coregonus coulieri and Hybognathus hankinsoni are reported for the first time from the Mackenzie drainage.

Observations on the Comparative Ecology of Two Species of Fish, Cottus asper and Cottus rhotheus, in British Columbia

junction with a limnological survey made by the British Columbia Game Department and the University of British Columbia. The author is grateful to Dr. P. A. Larkin for his interest, guidance and criticism throughout. Likewise, the advice, suggestions and criticisms of Dr. W. A. Clemens and Dr. C. C. Lindsey are sincerely appreciated. Collection of material was made possible through the joint sponsorship of the British Columbia Game Department and the University of British Columbia. The assistance of Mr. Craig MacPhee and Mr. Charles Lyons in collecting material is gratefully acknowledged. HABITAT.-The Arrow Lakes lie in a narrow, deep trench continuous with the Columbia River in the West Kootenay district of British Columbia. Upper Arrow Lake, about 40 miles long, is connected to Lower Arrow Lake, of similar length, by 15 miles of river. For the most part, the shoreline of both lakes is steep and rocky with a few sand or gravel beaches. Several beach seine hauls were taken at each of nine localities on the Arrow Lakes.