Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity

2003 ◽  
Keyword(s):  
Oncorhynchus Mykiss ◽  
Coho Salmon ◽  
Maximum Yield ◽  
Fold Increase ◽  
Current Yield ◽  
Watershed Restoration ◽  
Nutrient Additions ◽  
Juvenile Abundance ◽  
Average Size ◽  
Size At Age

<em>Abstract.</em>—Positive numerical responses in steelhead <em>Oncorhynchus mykiss </em>and coho salmon <em>O. kisutch </em>juvenile abundance and size, smolt yield, and smolts per spawner were obtained from watershed restoration in the Keogh River on northern Vancouver Island, British Columbia. Annual increases coincided with treatment and were compared with data from an untreated neighboring watershed (Waukwaas River). The steelhead population, now apparently capable of thriving, was below replacement recruitment prior to the addition of inorganic nutrients and instream habitat structures, the key components of several restoration activities. Annual increases in summer densities of steelhead juveniles were recorded as the rehabilitation treatments progressed from 1997 to 2000. Estimation of steelhead parr densities indicated a 3.8-fold increase over pretreatment or internal untreated values; increases in sites with both inorganic nutrient briquettes and habitat structure additions were 2.5–1.9 times higher than sites with nutrient additions or habitat structures alone. Average size-at-age of juvenile salmonids, by autumn, significantly increased through the years of rehabilitation treatment and compared with fish in the Waukwaas River. Steelhead smolt yield in 2000 increased to 2,338 fish, the highest yield since 1993, but lower than the historical average (>6,000) due to low escapement. Current yield was an improvement over the historic low (<1,000 steelhead smolts, 1998). Coho smolt yield increased to 74,500 or 20% above the historic average (62,000 smolts; 1975–1999), well above the record low counts of 1998 (22,000), but below the historic maximum yield (105,000; 1981). A significant increase in steelhead smolt recruitment at low escapement, from less than 2 to greater than 50 smolts per spawner, was observed over the last four brood years (1995–1998). The assessment now shifts to further benefits to smolt yield, which will require evaluation to 2004.

Experimental Analysis of Microhabitat Selection by Juvenile Steelhead (Oncorhynchus mykiss) and Coho Salmon (O. kisutch) in a British Columbia Stream

1993 ◽  
Vol 50 (6) ◽  
pp. 1198-1207 ◽  
Author(s):  
Kurt D. Fausch
Keyword(s):  
British Columbia ◽  
Oncorhynchus Mykiss ◽  
Habitat Complexity ◽  
Field Experiments ◽  
Coho Salmon ◽  
Early Summer ◽  
Microhabitat Selection ◽  
Salmon River ◽  
Identical Construction ◽  
Stream Salmonids

Replicate experiments were conducted in the Salmon River, British Columbia, during early summer 1990 to test the relative importance of velocity refuge, visual isolation, and overhead cover to microhabitat selection by steelhead (Oncorhynchus mykiss) parr and age-0 coho salmon (O. kisutch). Four types of artificial Plexiglas structures, the first three of identical construction, had different portions painted to provide increasing habitat complexity: velocity refuge alone, velocity refuge with visual isolation, all three features combined, and overhead cover alone. Steelhead parr selected structures with overhead cover alone or all three features significantly more often than those without overhead cover. Steelhead also selected structures adjacent to the swiftest velocities available and closest to other natural overhead cover, which accounted for most differences in use of the same structure in different locations. In contrast, few age-0 coho salmon used any structures. Those that did selected the three types of structures with velocity refuge about equally, but significantly more often than those with overhead cover alone, regardless of their location. Field experiments such as this hold promise for elucidating mechanisms of habitat selection by stream salmonids.

The Lobster (Homarus americanus) Fishery off Lower Argyle Southwestern Nova Scotia

1990 ◽  
Vol 47 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Nova Scotia ◽  
Fold Increase ◽  
Homarus Americanus ◽  
Weekly Basis ◽  
Index Numbers ◽  
Management Implications ◽  
Frequency Distributions ◽  
Fishing Season ◽  
Juvenile Abundance ◽  
Overall Mortality

Catch and effort data for the lobster (Homarus americanus) fishery of Lower Argyle, Nova Scotia, were obtained from sales slips on a weekly basis during 1978–87. Lobster size–frequency distributions were collected during at-sea sampling at the beginning and end of each fishing season. This fishery experienced a three-fold increase in landings (from 87.6 to 270 t) due to an increase in recruitment during the 10-yr study. The fishermen responded to the improved recruitment by increasing the total number of days fished per season by 41%. Overall mortality of recruited lobster (estimated from size–frequencies) rose from 55% in 1978 to 72–81% during 1985–87. During the 1987–88 fishing season, about 1 t lobster were removed per km2 of fishing grounds. Regression relationships between a prerecruit juvenile abundance index (numbers of lobster/trap haul) and the recruited yield one to two fishing seasons later were significantly correlated for 8–9 yr of data; equations predicted that lobster yields would remain high during the 1988–89 fishing season but decline in this area during 1989–90 fishing season. Management implications of forecasting recruitment yields 1–2 yr in advance and possible strategies to reduce major recruitment fluctuations in this fishery are discussed.

Changes in the Average Size and Average Age of Pacific Salmon

1981 ◽  
Vol 38 (12) ◽  
pp. 1636-1656 ◽  
Author(s):  
W. E. Ricker
Keyword(s):  
Growth Rate ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Gill Nets ◽  
Growing Seasons ◽  
Mean Size ◽  
Average Size

Of the five species of Pacific salmon in British Columbia, chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) are harvested during their growing seasons, while pink salmon (O. gorbuscha), chum salmon (O. keta), and sockeye salmon (O. nerka) are taken only after practically all of their growth is completed. The size of the fish caught, of all species, has decreased, but to different degrees and over different time periods, and for the most part this results from a size decrease in the population. These decreases do not exhibit significant correlations with available ocean temperature or salinity series, except that for sockeye lower temperature is associated with larger size. Chinook salmon have decreased greatly in both size and age since the 1920s, most importantly because nonmaturing individuals are taken by the troll fishery; hence individuals that mature at older ages are harvested more intensively, which decreases the percentage of older ones available both directly and cumulatively because the spawners include an excess of younger fish. Other species have decreased in size principally since 1950, when the change to payment by the pound rather than by the piece made it profitable for the gill-netters to harvest more of the larger fish. Cohos and pinks exhibit the greatest decreases, these being almost entirely a cumulative genetic effect caused by commercial trolls and gill nets removing fish of larger than average size. However, cohos reared in the Strait of Georgia have not decreased in size, possibly because sport trolling has different selection characteristics or because of the increase in the hatchery-reared component of the catch. The mean size of chum and sockeye salmon caught has changed much less than that of the other species. Chums have the additional peculiarity that gill nets tend to take smaller individuals than seines do and that their mean age has increased, at least between 1957 and 1972. That overall mean size has nevertheless decreased somewhat may be related to the fact that younger-maturing individuals grow much faster than older-maturing ones; hence excess removal of the smaller younger fish tends to depress growth rate. Among sockeye the decrease in size has apparently been retarded by an increase in growth rate related to the gradual cooling of the ocean since 1940. However, selection has had two important effects: an increase in the percentage of age-3 "jacks" in some stocks, these being little harvested, and an increase in the difference in size between sockeye having three and four ocean growing seasons, respectively.Key words: Pacific salmon, age changes, size changes, fishery, environment, selection, heritability

Planting row arrangement and nutrient management in geranium (Pelargonium graveolens) -garlic (Allium sativum) intercropping

2015 ◽  
Vol 49 (5) ◽  
Author(s):  
Santosh Singh
Keyword(s):  
Field Experiments ◽  
Maximum Yield ◽  
Cropping System ◽  
Fold Increase ◽  
Oil Yield ◽  
Cost Ratio ◽  
Economic Returns ◽  
Single Row ◽  
Equivalent Ratio ◽  
Planting Method

Field experiments were carried out at Lucknow, India to evaluate the optimum plant row arrangement of geranium and to study the effects of different rates of fertilizer N, P and Zn for the yield assessment in a geranium-garlic intercropping system. A paired row arrangement (40/80 cm) of geranium planting significantly increased the herb and essential oil yield over the conventional single row planting method (60x30cm). The former gave 20.6 % more herbage than the geranium single row intercrop system, with a 22.3 % increase in oil yield. Application of N at 160 kg ha<sup>−1</sup> significantly increased the herb and oil yields of geranium and bulb yield of garlic over the control and 80 kg N ha<sup>−1</sup>. Uptake of N by geranium was also significantly higher at 160 kg N ha<sup>−1</sup>. Application of phosphorus at 40 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup> proved significantly better than the no P control in the production of geranium oil and garlic bulbs. Uptake of Zn increased significantly up to 40 kg P<sub>2</sub>O<sub>5</sub> ha<sup>−1</sup>. Higher rates of P decreased the Zn uptake by the plants. Application of 30kg ZnSO<sub>4</sub>ha<sup>−1</sup> showed a significant response on the herb and oil yields over the no zinc control. The higher growth indices such as monetary equivalent ratio (1.45), area time equivalent ratio (1.44), land use efficiency (144 %) and benefit cost ratio (6.37) were recorded with a geranium paired intercrop system compared to other cropping systems. The geranium paired intercrop system proved advantageous in enhancing the economic returns by 1.73 – a two fold increase over the geranium single row, sole cropping system. It is concluded from this study that intercropping of garlic with a geranium paired row system proved highly beneficial in terms of getting higher economic returns by almost a factor of two over the conventional geranium single row planting method. A fertilizer addition of 160 kg N, 40 kg P<sub>2</sub>O<sub>5</sub> and 30 kg Zn SO<sub>4</sub> ha<sup>−1</sup> is recommended for achieving the maximum yield advantages in a geranium-garlic intercropping system.

Water velocity influences prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss irideus)

2008 ◽  
Vol 65 (2) ◽  
pp. 266-275 ◽  
Author(s):  
John J Piccolo ◽  
Nicholas F Hughes ◽  
Mason D Bryant
Keyword(s):  
Oncorhynchus Mykiss ◽  
Prey Capture ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Species Interaction ◽  
Water Velocity ◽  
Capture Probability ◽  
Prey Detection ◽  
Detection Distance ◽  
Drift Feeding

We examined the effects of water velocity on prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (sea-run rainbow trout, Oncorhynchus mykiss irideus) in laboratory experiments. We used repeated-measures analysis of variance to test the effects of velocity, species, and the velocity × species interaction on prey capture probability, prey detection distance, and swimming speeds during prey capture. We used 3D video analysis to assess the spatial and temporal characteristics of prey detection and capture. Coho and steelhead showed significant, velocity-dependent decreases in capture probability (~65% to 10%, with an increase of velocity from 0.29 to 0.61 m·s-1) and prey detection distance, with no effect of species and no velocity × species interaction. Neither velocity nor species affected prey interception speed; fish intercepted prey at their predicted maximum sustainable swimming speed (Vmax) at all velocities. Speed of return to the focal point increased significantly with increasing velocity, with no effect of species. At faster velocities, return speeds were faster than Vmax, indicating potential increases in energetic cost because of anaerobic swimming. The 3D analysis suggests that the reduction in capture probability was due to both reduced prey detection distance and a uniform decline in detection probability within the prey capture area.

scholarly journals Synthesis, Morphology, and Optical Properties of Au/CdS Hybrid Nanocomposites Stabilized by Branched Polymer Matrices

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
V. A. Chumachenko ◽  
A. P. Naumenko ◽  
O. A. Yeshchenko ◽  
N. V. Kutsevol ◽  
I. S. Bondarchuk
Keyword(s):  
Surface Plasmons ◽  
Free Exciton ◽  
Fold Increase ◽  
Hybrid Nanocomposites ◽  
Plasmon Band ◽  
Au Nps ◽  
Gold Nps ◽  
The One ◽  
Average Size ◽  
Cds Nanocomposites

Metal/semiconductor (Au/CdS) nanocomposites were synthesized in the solution of branched D-g-PAA polymer. TEM and DLS of Au/CdS/D-g-PAA nanocomposites revealed complicated nanocomposite structure consisting of the Au nanoparticles (NPs) of 6 nm in size surrounded by small CdS NPs with size of 3 nm. These nanocomposites formed the aggregates-clusters with average size of 50–800 nm. Absorption spectra of Au/CdS nanocomposites consist of the bands of excitons in CdS NPs and surface plasmons in Au ones. The surface plasmon band of gold NPs is red shifted and broadened in Au/CdS/D-g-PAA nanocomposites comparing to the one of Au NPs in Au/D-g-PAA proving the fact of close location of CdS and Au NPs in the synthesized Au/CdS/D-g-PAA nanocomposites. The PL spectra of Au/CdS nanocomposites originate from the radiative transitions in excitons in CdS NPs. The 4-fold increase of intensity of free exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA that is due to PL enhancement by local field of surface plasmons of Au NPs. Also, the 12-fold decrease of intensity of localized exciton PL is observed for CdS NPs in Au/CdS/D-g-PAA comparing to CdS ones in CdS/D-g-PAA. Most probably, it is due to passivation of the surface of CdS NPs carried out by the Au ones.

Production of germline transgenic Pacific salmonids with dramatically increased growth performance

1995 ◽  
Vol 52 (7) ◽  
pp. 1376-1384 ◽  
Author(s):  
Robert H. Devlin ◽  
Timothy Y. Yesaki ◽  
Edward M. Donaldson ◽  
Shao Jun Du ◽  
Choy-Leong Hew
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Cutthroat Trout ◽  
Transgenic Fish ◽  
Somatic Tissue ◽  
Growth Enhancement ◽  
Gene Construct ◽  
Average Size

Transgenic Pacific salmon have been produced by microinjection of a DNA construct consisting of chinook salmon (Oncorhynchus tshawytscha) growth hormone sequences driven by an ocean pout (Macrozoarces americanus) antifreeze protein promoter. This construct was retained in approximately 4% of fish derived from injected eggs, and resulted in dramatic enhancement of growth relative to controls. For coho salmon (O. kisutch) at 15 months of age, the average size of transgenic fish was more than 10-fold that of controls, with the largest fish more than 30-fold larger than nontransgenic siblings. Dramatic growth enhancement was also observed in transgenic rainbow trout (O. mykiss), cutthroat trout (O. clarki), and chinook salmon using this same gene construct. Transgenic coho salmon underwent precocious parr–smolt transformation during their first fall, approximately 6 months in advance of their nontransgenic siblings. At 2 years of age, five male transgenic coho salmon became sexually mature, and four of these transmitted the gene construct to sperm, the negative fish being transgenic in blood but not fin tissue. These results show that while some fish are mosaic for the gene construct in different tissues, most are transgenic in both germline and somatic tissue.

scholarly journals Chondrocyte-mediated depletion of articular cartilage proteoglycans in vitro

1985 ◽  
Vol 225 (2) ◽  
pp. 493-507 ◽  
Author(s):  
J A Tyler
Keyword(s):  
Articular Cartilage ◽  
Core Protein ◽  
Fold Increase ◽  
Acid Proteinase ◽  
Binding Region ◽  
Guanidinium Chloride ◽  
The Core ◽  
The Matrix ◽  
Average Size

The degradation of proteoglycan was examined in cultured slices of pig articular cartilage. Pig leucocyte catabolin (10 ng/ml) was used to stimulate the chondrocytes and induce a 4-fold increase in the rate of proteoglycan loss from the matrix for 4 days. Material in the medium of both control and depleted cultures was mostly a degradation product of the aggregating proteoglycan. It was recovered as a very large molecule slightly smaller than the monomers extracted with 4M-guanidinium chloride and lacked a functional hyaluronate binding region. The size and charge were consistent with a very limited cleavage or conformational change of the core protein near the hyaluronate binding region releasing the C-terminal portion of the molecule intact from the aggregate. The ‘clipped’ monomer diffuses very rapidly through the matrix into the medium. The amount of proteoglycan extracted with 4M-guanidinium chloride decreased during culture from both the controls and depleted cartilage, and the average size of the molecules initially remained the same. However, the proportion of molecules with a smaller average size increased with time and was predominant in explants that had lost more than 70% of their proteoglycan. All of this material was able to form aggregates when mixed with hyaluronate, and glycosaminoglycans were the same size and charge as normal, indicating either that the core protein had been cleaved in many places or that larger molecules were preferentially released. A large proportion of the easily extracted and non-extractable proteoglycan remained in the partially depleted cartilage and the molecules were the same size and charge as those found in the controls. There was no evidence of detectable glycosidase activity and only very limited sulphatase activity. A similar rate of breakdown and final distribution pattern was found for newly synthesized proteoglycan. Increased amounts of latent neutral metalloproteinases and acid proteinase activities were present in the medium of depleted cartilage. These were not thought to be involved in the breakdown of proteoglycan. Increased release of proteoglycan ceased within 24h of removal of the catabolin, indicating that the effect was reversible and persisted only while the stimulus was present.

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