bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of Dieldrin in an Alga (Scenedesmus obliquus), Daphnia magna, and the Guppy (Poecilia reticulata)
Authors: Reinert Robert E.
Published: April 2011

Scenedesmus obliquus, Daphnia magna, and Poecilia reticulata accumulated dieldrin directly from water; average concentration factors (concentration in organism, dry weight, divided by concentration in water) were 1282 for the alga, 13,954 for D. magna, and 49,307 (estimated) for the guppy. The amount accumulated by each species at equilibrium (after about 1.5, 3–4, and 18 days, respectively) was directly proportional to the concentration of dieldrin in the water. Daphnia magna and guppies accumulated more dieldrin from water than from food that had been exposed to similar concentrations in water. When guppies were fed equal daily rations of D. magna containing different concentrations of insecticide, the amounts of dieldrin accumulated by the fish were directly proportional to the concentration in D. magna; when two lots of guppies were fed different quantities of D. magna (10 and 20 organisms per day) containing identical concentrations of dieldrin, however, the amounts accumulated did not differ substantially.
Some Life History Aspects of the Rock Crab, Cancer irroratus, in the Gulf of Maine
Authors: Krouse Jay S.
Published: April 2011

Rock crabs, Cancer irroratus, were caught in wire lobster traps from 1968 through 1971 at Boothbay Harbor and in 1969 at Casco Bay, Maine. Females dominated the annual catches (except in Casco Bay) and width classes from 61 to 90 mm; while males were predominant above this size range. Rock crabs from Casco Bay were heavier at a given width than those from Boothbay Harbor. Soft-shelled females were caught mostly in the fall, while soft-shelled males appeared most frequently in late winter and early spring. The occurrence of newly berried females suggested that spawning (egg extrusion) took place in late fall and early winter, and hatching occurred in spring. Most female crabs attained sexual maturity between 70–80 mm carapace width, but a few matured at widths less than 70 mm.
The Percent Un-Ionized Ammonia in Aqueous Ammonia Solutions at Different pH Levels and Temperatures
Authors: Trussell R. P.
Published: April 2011

Previous studies have shown that the un-ionized ammonia molecule and not the ammonium ion is the form of the toxicant harmful to fish. Prior attempts to quantify the amount of un-ionized ammonia in an aqueous solution have been confusing. Data given here provide ready access to the amount of un-ionized ammonia over a range of temperature and pH that is common in temperate freshwater environments.
Occurrence of Glugea hertwigi in Lake Erie Rainbow Smelt (Osmerus mordax) and Associated Mortality of Adult Smelt
Authors: Nepszy Stephen J. , Dechtiar Alex O.
Published: April 2011

The occurrence of cysts of Glugea hertwigi, a microsporidian parasite, in Lake Erie rainbow smelt (Osmerus mordax) has been monitored since 1960 when it was first recorded. Annual sampling has shown that an increasing proportion (up to 87.5% in 1971) of the smelt population has been infected.An unusually severe mortality among adult smelt occurred during early May, 1971, in western and west central Lake Erie. Sampling of dead and obviously stressed smelt revealed that 97.3% of the males and 76.7% of the females were heavily loaded with cysts in the intestines and gonads, respectively. It is suggested that the parasite load contributed to the unusual severity of the normal postspawning mortality.
Sea Lions Wintering Along the Outer Coast of Vancouver Island
Authors: Smith Ian D.
Published: April 2011

Aerial counts conducted on the north and west coasts of Vancouver Island during four periods in the 1970–71 winter indicated that more than 1980 sea lions used a total of 15 haul-out areas. Evidence is presented indicating that many winter haul-out areas are often deserted in summer.
Two New Host Species for the Parasitic Fungus Ichthyophonus hoferi in the Northwest Atlantic
Authors: Hendricks Jerry D.
Published: April 2011

Microscopic examination of kidney tissues from eight Gulf of Maine fish species revealed cysts of the fungus Ichthyophonus hoferi, Plehn and Mulsow, in individuals from three species. Two of these species, the longhorn sculpin (Myoxocephalus octodecemspinosus) and the Atlantic cod (Gadus morhua), are new hosts for this parasite in Gulf of Maine waters. The other species, the yellowtail flounder (Limanda ferruginea), was previously reported as an Ichthyophonus host.
Endrin Toxicosis in Rainbow Trout (Salmo gairdneri)
Authors: Grant Blake F. , Mehrle Paul M.
Published: April 2011

In mature rainbow trout (Salmo gairdneri) receiving sublethal doses of endrin (4.3–145 × μg/kg body wt/day in 0.215–7.25 mg/kg of food) for 163 days and then forced to swim for 1 hr, the insecticide affected serum electrolytes, osmolality, total protein, cholesterol, cortisol, lactate, glucose, liver glycogen, and growth. Forced swimming alone altered 9 of 16 serum parameters examined. Apparent increases in serum Na and Cl and significant increases in osmolality and liver glycogen were directly related to dosage. A biphasic distribution of phosphate, total protein, and cholesterol with dosage was apparent. Glucose was increased about 50% by 145 μg/kg but was unaffected by lower doses. Variance analysis of zone electrophoretic patterns disclosed an in teraction between serum protein distribution and dose. Mobilization of liver glycogen was apparently inhibited by low doses and almost totally blocked by high doses. Correspondingly, trout given 14.5 μg/kg or more had lowered serum cortisol levels whereas the lowest dose elevated cortisol. Growth was inhibited appreciably by 145 μg/kg but not by lower doses. Visceral fat accumulated 4.8–8.7 μg endrin/g tissue in the 43 and 145 μg/kg exposures. We conclude that endrin caused dysfunction of physiologic processes critical to survival.
Flesh pH, Color, Thaw Drip, and Mineral Concentration of Pacific Halibut (Hippoglossus stenolepis) and Chinook Salmon (Oncorhynchus tshawytscha) Frozen at Sea
Authors: Botta J. R. , Richards J. F. , Tomlinson N.
Published: April 2011

The effects of brine-freezing and plate-freezing at sea on flesh pH, color (Hunter a/b ratio), thaw drip, and mineral concentration were determined at intervals during subsequent storage of the glazed, polyethylene covered fish at − 30 C.The difference in flesh pH between the brine- and plate-frozen samples was not significant for either halibut or salmon and the pH generally declined during storage.The changes in the Hunter a/b ratio of salmon were similar for both methods of freezing and the ratio generally increased slightly during storage.The thaw drip of halibut and salmon was less for the brine- than the plate-frozen samples after storage for 9–31 weeks whereas subsequently the brine-frozen samples had approximately equal or greater thaw drip than the plate-frozen. Except for plate-frozen halibut, thaw drip tended to increase with length of storage.Method of freezing did not significantly affect the potassium concentration of either halibut or salmon. For both species the sodium and chloride concentration of brine-frozen outside muscle was at least two to three times greater than brine-frozen inside or plate-frozen muscle.
Production of Agglutinating Antibodies in the Channel Catfish (Ictalurus punctatus) Against Chondrococcus columnaris
Authors: Schachte Jr. John H. , Mora Emilio C.
Published: April 2011

Fingerling channel catfish (Ictalurus punctatus) were injected subcutaneously and intramuscularly with an injectable Chondrococcus columnaris antigen to test for the production of agglutinating antibodies. The test fish of both routes of injection had a mean titer of 1:4337. No significant differences in titers between the two routes of injection were determined.
Hydrophone and Bow-Mount for Tracking Fish by Ultrasonic Telemetry
Authors: Stasko A. B. , Polar S. M.
Published: April 2011

An inexpensive, do-it-yourself hydrophone for tracking aquatic animals is described. It can be used with or without a preamplifier, on small or large boats. A new mounting arrangement used on the bow of a 25-m tracking vessel is discussed. It was used successfully in coastal waters at cruising speeds up to 9 knots (5 m/sec) and at slow speeds during rough weather in 30-knot (15.3 m/sec) winds.
A System for Maintaining Midwater Fishes in Captivity
Authors: Robison Bruce H.
Published: April 2011

A system for maintaining midwater fishes in captivity is described. The system employs a darkened, round-bottom boiling flask containing a structured flow of sea water. Damaging results of the fishes’ characteristic escape responses are prevented. Dipnetted specimens of Tarletonbeania crenularis were maintained aboard ship and ashore for periods of up to 72 hr.
A Modified Stake Net for Collecting Migrating Smolts of Atlantic Salmon (Salmo salar).
Authors: Hare G. M.
Published: April 2011

A modified stake net for collecting smolts of Atlantic salmon (Salmo salar) is described. The net is efficient for trapping smolts and, in addition, it practically eliminates problems with mortality of captured fish and accumulation of debris in the trap.
An Early Record of the Sea Lamprey (Petromyzon marinus) From Lake Ontario
Authors: Lark John G. I.
Published: April 2011

An 1835 record of the sea lamprey (Petromyzon marinus) in Lake Ontario is related to a hypothesis that it entered the lake through the Erie Canal after 1819.
An Initial Evaluation of Ethylene Oxide for the Sterilization of Formulated and Pelleted Fish Feeds
Authors: Trust T. J. , Wood A. J.
Published: April 2011

Satisfactory sterilization of dried pelleted fish foods was achieved with an ethylene oxide–carbon dioxide gas mixture (20:80). The growth rates of juvenile rainbow trout (Salmo gairdneri) fed on feed so sterilized were comparable to or better than those of trout fed the same feed not sterilized.
Mercury in the Marine Environment: Concentration in Sea Water and in a Pelagic Food Chain
Authors: Williams P. M. , Weiss H. V.
Published: April 2011

Mercury in seawater, in a pelagic food chain, and in bottom sediment was determined at a single station 430 km southeast of San Diego, California. The concentration of mercury in zooplankton slightly increased with depth of collection. The mercury content in almost all of the higher trophic levels of organisms collected at greater depths was indistinguishable from the concentration of mercury in zooplankton at these depths. Mercury concentration in the seawater column was essentially constant below 100 m and significantly higher at the surface. This vertical profile of mercury content is not ascribable to biological activity.
Effects of a Parasitic Gut Nematode on Consumption and Growth in Juvenile Rainbow Trout (Salmo gairdneri)
Authors: Hiscox J. I. , Brocksen R. W.
Published: April 2011

A technique was developed for differentially infecting juvenile rainbow trout, Salmo gairdneri, by introduction of the parasitic gut nematode, Bulbodacnitis ampullastoma. Desired infection levels were induced in trout with 80% success. B. ampullastoma affected growth and food consumption of trout in the laboratory. The effects of the parasite were evident at low and high ration levels. At low and starvation ration levels the parasite effected a withdrawal of the energy stores of the fish. At higher ration levels, the direct effects of the parasite were compounded by apparent parasite interference with food assimilation by the fish.B. ampullastoma was directly infective to a warmwater fish, Lepomis cyanellus.
A Simple Microscale Vacuum Collector for the Elution of Closely Situated Spots from Thin-Layer Chromatograms
Authors: Cheng Joseph Y.
Published: April 2011

A "homemade" device, utilizing disposable Pasteur pipettes and a side-armed test tube, is described for convenient quantitative removal and elution of closely separated spots from thin-layer chromatograms. Its simplicity of manipulation and "disposability" after use offer an excellent economic and timesaving elution technique for routine handling of numerous samples.
Optimum Economic Yield of a Fishery Given a Variable Price of Output
Authors: Anderson Lee G.
Published: April 2011

The majority of work done in the economics of fisheries uses the assumption of a fixed price of output. This paper describes the effects on the traditional fisheries model of relaxing this assumption, the most important of which, as far as regulation agencies are concerned are the negation of marginal cost of effort equaling marginal revenue of effort as the criterion for a social optimum, and the introduction of the possibility of multiple equilibria and multiple industry profit maxima. Also, some new insights on fishery management with variable price and different assumptions about the number of fisheries and the number of countries involved are pointed out.
Diel Migration and Breeding Cycle of Aglantha digitale from Two Locations in the Northeastern Pacific
Authors: Arai Mary Needler , Fulton John
Published: April 2011

The trachymedusa Aglantha digitale undergoes a diel migration in Saanich Inlet, Vancouver Island, British Columbia. The species has a single yearly breeding cycle at a high seas station in the northeastern Pacific.
Occurrence of the Shortnose Sturgeon (Acipenser brevirostrum), an Endangered Species, in Montsweag Bay, Maine
Authors: Fried Stephen M. , McCleave James D.
Published: April 2011

Thirty-one shortnose sturgeon (Acipenser brevirostrum) were caught in gillnets in Montsweag Bay in the Sheepscot River system during June and July of 1971 and 1972. Of nine fish preserved for study, six were longer than any previously documented and four exceeded the maximum total length previously postulated. These specimens represent the second population of this endangered species found in the Gulf of Maine.
Design of a Trapnet with Interchangeable Parts for the Capture of Large and Small Fishes from Varying Depths
Authors: Beamish R. J.
Published: April 2011

The use of new materials and a modification of the basic trapnet design produced nets that fished successfully for large and small fishes in areas where conventional collecting techniques were difficult to apply. Parts of the trap can be interchanged to fish at depths of 1–5 m.
Some Simple Methods of Estimating Mortality Rates of Exploited Fish Populations
Authors: Ssentongo G. W. , Larkin P. A.
Published: April 2011

Some simple equations are derived from mortality functions that enable estimation of the total mortality coefficient from the mean age and the age of first capture, or the mean length and the length of first capture, of fish in a catch.
Effects of Temperature on Embryonic Development of Lake Herring (Coregonus artedii)
Authors: Colby Peter J. , Brooke L. T.
Published: April 2011

Embryonic development of lake herring (Coregonus artedii) was observed in the laboratory at 13 constant temperatures from 0.0 to 12.1 C and in Pickerel Lake (Washtenaw County, Michigan) at natural temperature regimes. Rate of development during incubation was based on progression of the embryos through 20 identifiable stages.An equation was derived to predict development stage at constant temperatures, on the general assumption that development stage [Formula: see text] is a function of time (days, D) and temperature (T). The equation should also be useful in interpreting estimates from future regressions that include other environmental variables that affect egg development.A second regression model, derived primarily for fluctuating temperatures, related development rate for stage [Formula: see text], expressed as the reciprocal of time, to temperature (x). The generalized equation for a development stage is:[Formula: see text]In general, time required for embryos to reach each stage of development in Pickerel Lake agreed closely with the time predicted from this equation, derived from our laboratory observations. Hatching time was predicted within 1 day in 1969 and within 2 days in 1970.We used the equations derived with the second model to predict the effect of the super-imposition of temperature increases of 1 and 2 C on the measured temperatures in Pickerel Lake. Conceivably, hatching dates could be affected sufficiently to jeopardize the first feeding of lake herring through loss of harmony between hatching date and seasonal food availability.
Some Aspects of the Life History of Calanus plumchrus in the Strait of Georgia
Authors: Fulton John
Published: April 2011

Calanus plumchrus did not feed during the last 7 months of its life cycle and the fecundity of each female was dependent on the size of the animal. Each female produced an average of 535 eggs from 9.5 broods over a breeding period of 85 days. Eggs were released in water deeper than 300 m and were calculated to move towards the surface about 26 m/day. Growth from egg to stage V took about 100 days. Growth rate was calculated to be 10.6%/day.
Effects of Formaldehyde on Salt Extractable Proteins of Gadoid Muscle
Authors: Castell C. H. , Smith B. , Dyer W. J.
Published: April 2011

Addition of formaldehyde to fresh cod muscle, to give concentrations of 10 to 200 ppm, brought about marked decreases in the extractable protein content during holding periods of 24 hr or less at 0 C. Similar levels of formaldehyde, produced during frozen storage of gadoid (Atlantic cod, Gadus morhua, pollock, Pollachius virens, cusk, Brosme brosme, and silver hake, Merluccius bilinearis), fillets at −5 C, brought about similar reductions in the extractable proteins. Comparative tests showed that, in the concentrations normally encountered in deteriorating frozen gadoid fillets, formaldehyde was a much more active protein-insolubilizing agent than free fatty acid. It is evident that in these protein changes more than one mechanism is involved. Observed species-differences in the extent to which fish proteins became insolubilized during storage appeared to be related to presence or absence of these different mechanisms. The more rapid and more extensive denaturation of most gadoid fillets in frozen storage than of fillets of nongadoid species appears to be directly related to the presence of muscle enzyme of the former group that is capable of producing formaldehyde from trimethylamine oxide, which is absent in the muscle of the nongadoid species so far tested.
Masking or Neutralizing Muddy Flavor in Rainbow Trout (Salmo gairdneri) by Smoking and Canning Processes
Authors: Iredale D. G. , Shaykewich K. J.
Published: April 2011

Smoke processing methods and canning treatments were applied to muddy-flavored rainbow trout in an attempt to minimize this undesirable condition. The final smoking method, which can be readily applied commercially, resulted in a product which was highly acceptable to a "consumer" panel, although the muddy taint remained discernible to an expert panel. The most successful canning method, which consisted of steam precooking fillet strips of rainbow trout and subsequently adding vegetable oil or smoke-flavored vegetable oil to the cans, resulted in an end product which was rated as "not muddy" by an expert panel.
Intertidal Feeding of Winter Flounders (Pseudopleuronectes americanus) in the Bay of Fundy
Authors: Wells Barbara , Steele D. H. , Tyler A. V.
Published: April 2011

Flounders captured in summer in the intertidal zone at high tide fed mainly on food species that live in that zone. Flounders captured in the subtidal zone fed partially on food species that live there, and partially on intertidal food species. From these feeding habits, and from the magnitude of the movement into the intertidal zone (previously reported), we conclude that large intertidal areas are major feeding grounds for winter flounder. The quantities of filamentous algae in the stomachs suggest that winter flounders can utilize plant material.
Modelling Primary Production in Water Bodies: A Numerical Approach that Allows Vertical Inhomogeneities
Authors: Fee Everett J.
Published: April 2011

A new model for computing integral daily phytoplankton primary production is described. The model incorporates vertical variations of algal biomass, complex photosynthesis vs. light responses, nonexponential extinction of light vs. depth, and any distribution of surface light over a day. The basic approach is to combine measured relations for photosynthetic rate vs. light, light vs. depth, and light vs. time in an interpolative scheme rather than attempting to fit equations to the data and using the resulting equations to obtain a mathematical solution. The model is general and should have wide applicability. Model predictions agreed well with in situ measurements of production.
Does Eyestalk Ablation Accelerate Molting in the Lobster Homarus americanus?
Authors: Sochasky Jeffrey B. , Aiken D. E. , McLeese D. W.
Published: April 2011

Contrary to published results obtained with larger Homarus americanus, bilateral eyestalk ablation induces precocious molting in lobsters about 60 mm carapace length. The observed "acceleration" appears to result from the prevention or termination of a D0 development plateau. However, limb regeneration in eyestalkless lobsters appears to be inhibited.
1-Methyladenosine Hydrolase of Starfish (Pisaster ochraceous)
Authors: Tarr H. L. A.
Published: April 2011

A nucleosidase specific for 1-methyladenosine was purified up to 42-fold from mature testes of starfish, and less extensively from mature ovaries, stomach tissue, and pyloric caeca, by extraction, ammonium sulphate fractionation, and DEAE-cellulose chromatography. The enzyme, the products of which were 1-methyladenine and D-ribose, was free from nucleoside phosphorylase activity and had the following properties. The pH optimum was 7.8–8.0 with half maximum activity at pH 6.2 and 9.5; the enzyme was rapidly inactivated at 40 C and by freezing and thawing; of 10 purine and pyrimidine ribonucleosides and deoxyribonucleosides studied, only 1-methyladenosine was hydrolyzed; the Km was 6.65–7.15 × 10−4 M; 1-methylinosine and 1-methylguanosine were noncompetitive inhibitors; the Ki for these were 1.25 × 10−4 M and 1.4 × 10−4 M, respectively. Vmax values of from 6.3–10.4 μmoles of 1-methyladenosine hydrolyzed per mg of enzyme protein per hr at 25 C were calculated. It is not known if this enzyme plays a role in the in vivo formation of 1-methyladenine, which induces maturation of starfish oocytes.
Effects of Egg Concentrations of DDT and Dieldrin on Development in Winter Flounder (Pseudopleuronectes americanus)
Authors: Smith Roderick M. , Cole Charles F.
Published: April 2011

Abnormal gastrulation and a high incidence (mean = 39%) of vertebral deformities at hatching were encountered in developing eggs from winter flounder, Pseudopleuronectes americanus, experimentally exposed as adults to sublethal concentrations of DDT. Bone erosion and hemorrhaging at the vertebral junctures were often observed in conjunction with the vertebral deformities. No abnormal gastrulation and a lower incidence (mean < 1%) of vertebral deformities without bone erosion and hemorrhaging were encountered in controls. DDT concentrations in the eggs ranged from 0.39 to 4.60 (mean = 2.42 ppm) compared to 0.11–0.57 ppm (mean = 0.22 ppm) in the eggs from control flounder. No observable effect on development was noted in eggs from adults exposed experimentally only to dieldrin except in two lots of eggs most of which were dead and necrotic at spawning and contained 1.74 and 1.21 ppm dieldrin. No direct effect on fertilization mortality was due to gamete concentrations of DDT and dieldrin and no residues of either insecticide were detected in the milt from exposed or control male flounder.
Productivity of the Oceans
Authors: Hempel G.
Published: April 2011

The ratio of total world fish landings to annual primary production, about 1:3000, suggests a poor exploitation of the biological productivity of the world ocean. The ratio ranges from 1:100 in the most intensively exploited shelf areas and coastal upwelling regions to beyond 1:100,000 in the central oceanic gyres. Regional differences are a thousand-fold higher in fishing yields than in primary production.The yield differences among areas are caused by three groups of factors: 1, Primary production, which is subject to environmental factors; 2, Length, structure, and transfer efficiency of the food chain, which connects the primary producers with the exploited fish population and determines the ratio between fish production and primary production. Wherever primary production is high, the ratio tends to be favorable, particularly in shelf and upwelling areas. The short pelagic food chains of the cold-water regions lead to rich exploitable resources of pelagic fish, whales, and krill; 3, The rate of exploitation of the fish resources. The ratio between potential production and the actual yield is poor in areas with low fish production, where exploitation is difficult and expensive.Any attempt to increase world fishery yields aims at a change of one of the three groups of factors. Artificial changes in primary production are of local importance only. They are possible through discharge of nutrients and waste energy. Changes in the length and structure of food chains are achieved through a shift of interest to abundant groups of organisms that are closer to primary production. Exploitation of krill and the mass culture of mussels are promising examples. Increases in the exploitation rate can be achieved through better adjustment of fishing to population dynamics of heavily exploited stocks and through extension of pelagic fisheries, particularly in certain parts of the southern hemisphere and the open ocean.
Peru: A Case Study in the Establishment of a Food Fish Industry for a Developing Country
Authors: Appleyard W. P.
Published: April 2011

Based on Peruvian experience, the author describes the progress made over the past two years in establishing the food fish industry. Reference is made to the initial approach of the Government in setting up a separate Ministry of Fisheries while consideration is given to the influential and paradoxical situation of the Peruvian anchoveta industry. The role and the relation of the Government and the private sector are examined. The approach to various aspects of the food fish industry is commented on as the progress in developing the catching effort, the infrastructure, the training activities, the fish inspection service, the processing facilities, the commercial system, and the consumer education program is analyzed. Methods of funding, function of the multilateral and bilateral agencies, policy toward fishing cooperatives and artisanal fishermen, and place of the foreign factory trawler, are examined. Future opportunities are briefly discussed. An attempt is made to illustrate the necessities, problems, possible approaches, and opportunities of the food fish industry in a developing country.
Management and Development of Fisheries in the Eastern Central Atlantic
Authors: Gulland J. A. , Troadec J. P. , Bayagbona E. O.
Published: April 2011

The resources of the eastern central Atlantic can be divided into two parts: the northern, temperate or subtropical zone in an area where cool upwelling water gives high production of pelagic species like the sardine, sardinella, mackerel, and horsemackerel, and of demersal species like the various sea breams, hake, and several species of cephalopods; the tropical zone, roughly from Cape Verde southward, is less rich although it contains a great variety of species.Distribution of human population and of potential local markets is uneven, the greater part being in the tropical area. Except for the sardine and other fisheries of Morocco, the main locally based fisheries have been in this region. Until recently there have been mostly small inshore canoe fisheries, but the rich upwelling areas have been a strong attraction for fishermen from outside the region. These have included trawl fishermen from southern Europe, mainly interested in high-value species such as sea bream; Japanese fishermen interested in these same species and in squid, octopuses, and cuttlefish; fishermen from eastern Europe, using trawls (later purse seines) for pelagic species such as mackerel and horsemackerel; and fishermen from Scandinavia and South Africa, catching pelagic fishes, particularly sardinellas, for reduction to fish meal. Local countries have been developing their fleets; in the tropical area these include large long-range vessels for operating in the richer areas to the north and also to the south in the Benguela current.Several stocks in the region have become or are becoming heavily exploited. Necessary management action includes collecting and analyzing the basic data to assess the stocks, limiting the total amount of fishing to the level appropriate to each stock, and assuring an increasing participation in the offshore fisheries by coastal African countries.There is clearly a need for bilateral or multilateral arrangements between countries in the zone of high human population but low fish production and countries in the more productive but less populated zone. This would benefit both groups and stimulate intra-African trade and cooperation.
Changes in Plasma Constituents During Spawning Migration of Pacific Salmons
Authors: Triplett E. , Calaprice J. R.
Published: April 2011

Blood constituents were measured in salmon (Oncorhynchus gorbuscha and O. nerka) at various times during the spawning migration. Values for blood sodium, potassium, calcium, glucose, protein, and hematocrit suggested that during early stages of migration through post-spawning these fish experience a syndrome reminiscent of mammalian hypoadrenocorticism. The reverse was true of fish in advanced stages of senescence. Older fish also suffered ascorbate deficiency with a resultant necrosis of the skin. This deficiency was corrected by intraperitoneal injection of ascorbate. Various forms of hormone therapy applied to senescent fish were unsuccessful in prolonging their life appreciably.
Production and Movement of Juvenile Rainbow Trout (Salmo gairdneri) in a Headwater of Bothwell's Creek, Georgian Bay, Canada
Authors: Alexander D. Ross , MacCrimmon Hugh R.
Published: April 2011

Within the 21,500 m2 headwater, the standing population of juvenile rainbow trout reached a high of 7.05 g/m2 in October. Production was maximum during August at 1.77 g/m2. Total annual production is calculated at 284.5 kg (13.2 g/m2). Spring emigrants (no less than 4830 fish weighing 69 kg) were age I (91%) and age II. Minimum calculated ratio of production to yield as emigrants was 4.1:1. Comparatively few age 0 fish emigrated during summer. Because of their demonstrated capability to produce juveniles, sensitive headwaters must be preserved from ecological disturbance to assure self-perpetuating rainbow trout populations in the Great Lakes.
Primary Production in Lakes Ontario and Erie: A Comparative Study
Authors: Glooschenko Walter A. , Moore James E. , Munawar Mohiuddin , Vollenweider R. A.
Published: April 2011

Primary production values in Lake Ontario were low in winter, reached a maximum in midspring, declined during summer, and slightly increased in fall. Rate of increase of production for inshore waters (< 20 m depth) was greater especially in spring and early summer with a greater maximum reached earlier than in offshore waters. Assimilation numbers, mgC fixed/mg chlorophyll a per hour, in Lake Ontario were fairly constant over the lake with a yearly range of 1.2–1.6. Primary production showed a linear relationship to chlorophyll a concentration, as also occurred in Lake Erie.Lake Erie primary production varied in its three basins. Seasonally, in the Eastern Basin, production was highest in spring with a midsummer decline, and small peaks in fall. The Western Basin had a maximum in midsummer whereas the Central Basin had peaks in late summer and early fall. Assimilation numbers were highest in the Western Basin (up to 3.5 mgC/mg chlorophyll a per hour) and lowest in the mid-Central Basin and Eastern Basin with values of approximately 1.4 mgC/mg chlorophyll a per hour. A definite westerly increase of assimilation number was observed.Up to early summer, the two lakes were fairly equal in surface production but integral photosynthesis, mgC/m2 per hour was higher in Lake Ontario than in Lake Erie. The same was valid in November and December. In summer, Lake Erie was higher in production on both a mgC/m3 per hour and mgC/m2 per hour basis. For the period, April–December, Lake Ontario's total estimated yield was 170 gC/m2, whereas for Lake Erie values of 160, 210, and 310 gC/m2 were found for the Eastern, Central, and Western basins, respectively.
Long-Chain Monoethylenic and Other Fatty Acids in Heart, Liver, and Blubber Lipids of Two Harbor Seals (Phoca vitulina) and One Grey Seal (Halichoerus grypus)
Authors: Ackman R. G. , Hooper S. N.
Published: April 2011

The fatty acids of triglycerides in the hearts from two harbor seals (Phoca vitulina) and one grey seal (Halichoerus grypus) differed quantitatively in some details from those in the blubber. The 22:1 found in the heart triglycerides was about half that in the blubber triglycerides. Isomer distributions differed within 20:1 acids in the two triglycerides for both species, the higher proportion of 20:1ω11 fatty acid deposited in the heart than in the blubber indicating more active chain shortening from 22:1. The fatty acids of phospholipids of all three hearts and livers also differed quantitatively in some fatty acid details indicating organ-specific compositions. These also differed from compositions of similar lipids in terrestrial animals in their generally marine fatty acid compositions which were established for the blubbers. The grey seal (age 3 mo) showed unusual percentages of linoleic types of acids in the organ lipids and also a curious enrichment in ω7 monoethylenic acids. Dietary factors are believed to be responsible for differences between this animal and the two harbor seals (ages 10 and 23 mo).
Length–Weight Relations of Pacific Ocean Perch (Sebastes alutus) in the North Pacific Ocean
Authors: Westrheim S. J. , Snytko V. A.
Published: April 2011

Length–weight relations for Pacific ocean perch (Sebastes alutus) were determined by the iterative method from data collected aboard Soviet research vessels in the North Pacific Ocean, from Kamchatka, USSR (53°N lat), to Oregon, USA (44°N lat). Interarea values of a (in W = aLb) ranged from 0.0076028 (females, E Bering Sea) to 0.054000 (females, W Bering Sea); and b, from 2.6345 (females, W Bering Sea) to 3.1694 (females, E Bering Sea). Empirical tests indicated that individual area formulae generally produced acceptable calculated weights. Interarea comparisons of calculated weights provided additional evidence of the existence of discrete stocks and two subspecies of Pacific ocean perch in the North Pacific Ocean.
Life Cycles of Three Limnetic Copepods in a Beaver Pond
Authors: Carter John C. H.
Published: April 2011

In a small, shallow beaver pond near Georgian Bay, Ontario, life histories of each of the three limnetic copepods found were basically similar in the 3 yr 1970–72 although the patterns were occasionally obscured. Cyclops bicuspidatus thomasi presumably emerged from diapause at stage C 4 when the ice broke and went through one complete cycle to C 4 in 3–4 wk, reentering diapause in late spring. Mesocyclops edax emerged from diapause at C 4 slightly later in spring and underwent four complete cycles, reentering diapause in midautumn; normal time to complete a generation was about 1 mo. Diaptomus reighardi hatched from resting eggs in early May and produced four complete generations, the last maturing in early autumn; development of spring and summer generations required 1 mo and that of autumn generations about [Formula: see text] mo. During 1972 lowered water levels resulted in increased heat content of the pond per unit volume and this was reflected in some acceleration of development rates of M. edax and D. reighardi. At most sampling times M. edax had about double the fecundity of D. reighardi indicating a correspondingly high mortality rate that might be the result of lower egg viability, cannibalism, or competition between nauplii of the two species.
Effect of Complexation on Toxicity of Copper to Fishes
Authors: Pagenkopf Gordon K. , Russo Rosemarie C. , Thurston Robert V.
Published: April 2011

Copper (Cu) is highly complexed by carbonate and hydroxide ions in natural waters and this complexation determines the concentration of copper species in solution. Results of detailed equilibrium calculations on data from bioassays where alkalinity, pH, hardness, and total copper concentration are different indicate that copper(II) is the chemical species that is toxic to fishes and that alkalinity is the factor controlling copper(II) concentration.
Northern Extension of Known Range of Atlantic Menhaden (Brevoortia tyrannus)
Authors: Peppar John L.
Published: April 2011

Ten specimens of Atlantic menhaden (Brevoortia tyrannus) were taken in salmon trapnets near Dalhousie, New Brunswick, from June 18 to July 19 in 1973. The northern limit of range of the species was previously considered to be western Nova Scotia.
Introduction to Limnology in Canada
Authors: Harvey Harold H. , Geen Glen H.
Published: April 2011

not available
Studies of Northern Alberta Lakes and their Fish Populations
Authors: Paetz M. J. , Zelt K. A.
Published: April 2011

The limnology and fisheries of four Alberta lakes (Cold Lake, Lac La Biche, Lesser Slave Lake, and Wabamun Lake) were described. The general description included glacial history, climate, human development, physical and chemical characteristics, plankton and macroinvertebrates, and fish species composition. Age–length relation for lake whitefish (Coregonus clupeaformis) and ciscoes (C. artedii) from the individual lakes was presented and compared with the limnological condition of the particular lake. The commercial lake whitefish yield of each lake was also compared with the physical and chemical characteristics.
Swimming Depth of Adult American Eels (Anguilla rostrata) in a Saltwater Bay as Determined by Ultrasonic Tracking
Authors: Stasko A. B. , Rommel Jr. S. A.
Published: April 2011

Pressure-sensing ultrasonic transmitters in the gut were used to determine the swimming depth of five American eels (Anguilla rostrata) in Passamaquoddy Bay, New Brunswick, in autumn. The eels made frequent dives from surface to bottom, in places diving at least 45 m deep, at vertical speeds to 76 cm/s. About one quarter of the time was spent near the surface; very little time was spent near the bottom or at any constant intermediate depth range.
Occurrence of Pacific Staghorn Sculpin (Leptocottus armatus) in the Southern Bering Sea
Authors: Paulson Alan C. , Smith Ronald L.
Published: April 2011

The known geographic range of Leptocottus armatus is extended to Izembek Lagoon in the Bering Sea. Notes on its occurrence in the Izembek area are presented.
Fecundity and Gonad Observations of the American Eel, Anguilla rostrata, Migrating from Chesapeake Bay, Virginia
Authors: Wenner Charles A. , Musick J. A.
Published: April 2011

Fecundity of the American eel, Anguilla rostrata, was estimated from 21 specimens migrating from Chesapeake Bay during November 1970. The relationship between total length and fecundity is log y = −4.29514 + 3.74418 log x where y is fecundity and x is total length (mm) and between total weight and fecundity is log y = 3.22990 + 1.1157 log x where y is fecundity and x is total weight (g). Gonadal condition was described statistically and histologically. Specimens migrating from Chesapeake Bay are more sexually mature than either American eels migrating from Canadian waters or European eels, Anguilla anguilla, migrating from Europe. The significance of these findings with regard to Tucker's hypothesis of European eels being more sexually advanced at the onset of the spawning migration is discussed.
Influence of a Thermal Effluent on Movement of Brown Bullhead (Ictalurus nebulosus) as Determined by Ultrasonic Tracking
Authors: Kelso John R. M.
Published: April 2011

Brown bullhead (Ictalurus nebulosus) were captured between July 31 and August 23, 1973, both within the influence of a thermal discharge in Lake Ontario and at a control site. Ten fish were marked with ultrasonic transmitters and continuously tracked for periods of 29–344 min in the influence of the discharge. Five bullheads from the control site were similarly treated and monitored.Fish caught and released in the discharge area remained within 50–700 m of the release point, turned frequently and sharply, and swam at an average speed of 30 cm/s. Control fish moved along shore, average speed 48 cm/s, in straighter paths up to 4200 m from the release point. On the morning following release, only 20% of fish released in the discharge were still there, indicating that association with the plume was of short duration. The study indicates that the thermal discharge can interrupt or alter normal movement patterns of brown bullhead.
Fine Structure of the Retinal Pigment Epithelium, Bruch's Membrane, and Choriocapillaris in the Northern Pike (Esox lucius)
Authors: Braekevelt C. R.
Published: April 2011

The fine structure of the retinal pigment epithelium, Bruch's membrane, and the choriocapillaris has been studied by light and electron microscopy in the adult northern pike (Esox lucius).The pigment epithelium is composed of a single layer of large cells. Each epithelial cell has abundant mitochondria, smooth endoplasmic reticulum, myeloid bodies, phagosomes, and pigment granules. Rough endoplasmic reticulum and ribosomes are scarce.The scleral or basal border of the epithelial cell is not infolded whereas the vitreal or apical surface displays numerous, fine, elongated processes which surround the inner and outer segments of the photoreceptors.Bruch's membrane is composed of three layers. The innermost layer is the basal lamina of the pigment epithelium. The outermost layer is the basal lamina of the choriocapillaris endothelium. Between these basal laminae is a layer of fine fibrils. The overall thickness of Bruch's membrane is 3.5–4 μ posteriorly.The endothelial wall of the choriocapillaris bordering Bruch's membrane is typically very thin but nonfenestrated. Vesicles are common in the endothelial cytoplasm.This region of the pike eye differs morphologically from that described for most other vertebrates.
Acute Toxicity of Nitrite to Rainbow Trout (Salmo gairdneri)
Authors: Russo Rosemarie C. , Smith Charlie E. , Thurston Robert V.
Published: April 2011

Flow-through bioassays on the acute toxicity of nitrite to rainbow trout (Salmo gairdneri) of four different sizes (2–235 g) showed median lethal concentration (LC50) values for 4 days ranging from 0.19 to 0.39 mg/liter NO2–N. For 12-g rainbow trout the asymptotic LC50 was 0.14–0.15 mg/liter NO2–N after 8 days.
Conceptual Aspects of Strategic Planning for Fishery Management and Development
Authors: MacKenzie W. C.
Published: April 2011

The decision-making component of the process is supported by mechanisms to provide for continuous adjustment of planning and adaptation to an evolving environment. These include a) formally organized input from clients, b) "feedback" in the form of goal-attainment indicators or quantitative/qualitative measures of social and industrial changes and of program impact, and c) policy research or analysis directed to minimization of the intuitive element in decision making.Planning is conceived to be an integrated process combining a) definition of goals and establishment of priorities or policy objectives, essentially a political activity, b) selection of policies or strategies for the achievement of indicated objectives and the establishment of guidelines for programming, based on interaction between political leadership and expert advisers, and c) selection of programs and project design, i.e. tactical or operational planning, a specialist activity.
Swimming Speeds of Yellow Perch (Perca flavescens) Following an Abrupt Change in Environmental Temperature
Authors: Otto Robert G. , Rice John O'Hara
Published: April 2011

Groups of yellow perch (Perca flavescens) were acclimated to constant temperatures of 10 and 20 C. Acclimation temperatures were then abruptly reversed. Critical swimming speeds were determined prior to and following the temperature change at 24-h intervals. Adjustment (acclimation) of fish subjected to an increase in temperature was immediate. Fish subjected to a decrease in temperature required less than 24 h to regain maximum swimming capability.
Effects of Thyroid Hormones on Behavior of Yearling Atlantic Salmon (Salmo salar)
Authors: Godin J.-G. , Dill P. A. , Drury D. E.
Published: April 2011

Swimming activity, aggressive behavior, and upstream orientation of yearling Atlantic salmon (Salmo salar) treated with 6.43 × 10−11 M thyroxine were significantly lower than those of control fish injected with solvent alone. Two concentrations of triiodothyronine (7.43 × 10−11 M; 7.43 × 10−10 M) caused similar but less pronounced effects.Because similar behavioral modifications accompany smolt migration, we hypothesize that thyroid hormones may play a role in arousing migratory tendencies in Atlantic salmon.
Fish Kill Due to "Cold Shock" in Lake Wabamun, Alberta
Authors: Ash G. R. , Chymko N. R. , Gallup D. N.
Published: April 2011

A thermal fish kill due to "cold shock" caused by a mechanical failure in the steam electric generating unit was observed in Lake Wabamun, Alberta on February 8, 1973 in the region of the discharge canal. The most rapid temperature decline occurred in the initial 30 min after shutdown when the temperature dropped 16.9 C (21.8 to 4.9 C). The major fish species affected included spottail shiners (Notropis hudsonius) and northern pike (Esox lucius). The freshwater clam Anodonta sp. did not appear to be affected.
Indirect Fluorescent Antibody Technique for Detection of RM Bacterium of Rainbow Trout (Salmo gairdneri)
Authors: Johnson G. R. , Wobeser G. , Rouse B. T.
Published: April 2011

An indirect fluorescent antibody technique was evaluated as a method for the rapid detection of RM bacterium of rainbow trout (Salmo gairdneri). Antibody produced by inoculating rabbits with washed RM bacterium antigen was combined with commercially prepared fluorescein-labelled antiglobulin. The technique demonstrated strong specificity for the RM bacterium in washed and broth cultures, and in kidney smears from experimentally infected rainbow trout.
Age and Growth of Dogfish Squalus acanthias in British Columbia Waters
Authors: Ketchen K. S.
Published: April 2011

Ages of dogfish have been determined from markings on the second dorsal spine by a technique that enables use of badly worn spines from relatively large fish to correct for the tendency to underestimate age. While the technique may have led to slight overestimation of age, particularly of dogfish from Hecate Strait, there is some corroborating evidence for the Strait of Georgia drawn from length-frequency distributions, sizes of fish in relation to reproductive stages, and assumptions about the average annual net uptake of mercury. It is tentatively concluded that the growth curve for females, expressed in terms of the von Bertalanffy equation, has parameters of K = 0.048, [Formula: see text], and t0 = −4.88 yr. Parameters suggested for males are: K = 0.070, [Formula: see text], and t0 = −4.70 yr. The implication emerging from these results is that females and males on the average take 23 yr and 14 yr, respectively, to reach maturity.
Experimental Study of Galvanonarcosis for Rainbow Trout (Salmo gairdneri) Immobilization
Authors: Kynard Boyd , Lonsdale Edward
Published: April 2011

Galvanonarcosis treatments had no significant effect on growth or photonegative behavior of rainbow trout (Salmo gairdneri). The data indicate the potential usefulness of the technique for immobilizing fish.