Lamprey Parasitism of Rainbow Trout in Southern Georgian Bay

1967 ◽  
Vol 24 (12) ◽  
pp. 2539-2548 ◽  
Author(s):  
A. H. Berst ◽  
A. A. Wainio
Keyword(s):  
Rainbow Trout ◽  
Fork Length ◽  
Georgian Bay ◽  
Low Level ◽  
Spawning Streams

Of 2614 adult rainbow trout sampled from the Nottawasaga River of Georgian Bay during the period of 1961–67 inclusive, approximately 7.1% had one or more lamprey marks. The trout ranged in fork length from 10 to 33 inches (25 to 84 cm). However, lamprey marks were present only on fish over 16 inches (40 cm) in length. Multiple scarring was found on 30% of the trout that were marked. The incidence of marked fish reached a maximum of 17.2% in the spring of 1962, then declined to 1.3% in the fall of the same year. This decline was coincident with a reduction in the lamprey population after experimental lampricide treatment of the Nottawasaga River and adjacent lamprey spawning streams during 1960 and 1961. The incidence of marked fish remained at a relatively low level for a period of 4 years, then increased substantially, after the presumed recruitment of metamorphosed lampreys during 1966 and 1967.

Failed predation in Late Ordovician gastropods (Mollusca) from Manitoulin Island, Ontario, CanadaThis article is one of a selection of papers published in this Special Issue on the theme The dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.

2008 ◽  
Vol 45 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Jan Ove R. Ebbestad ◽  
Christopher A. Stott
Keyword(s):  
Success Rate ◽  
Late Ordovician ◽  
Size Class ◽  
Low Energy ◽  
Special Issue ◽  
Georgian Bay ◽  
Low Level ◽  
Shell Repair ◽  
Number Of Individuals ◽  
Selection Of

Shell repairs resulting from presumed failed predation are documented in gastropods from the Late Ordovician (Cincinnatian; Richmondian) mid-to-upper Kagawong Submember of the Georgian Bay Formation on Manitoulin Island, Ontario, Canada. The bryozoan–mollusc biota and associated sediments generally suggest nearshore, shallow (<10 m), low energy (lagoonal), and perhaps mesotrophic to eutrophic conditions. Two sample sets from this unit have been studied for shell repair. One of the more commonly applied estimates of shell repair frequencies involves division of the number of individuals with at least one scar by the total number of individuals in the sample (the Individuals with scars method). Using this calculation, 207 specimens of Lophospira trilineata Ulrich and Scofield yielded a shell repair frequency of 4.8%; in 28 specimens of Trochonemella sp. the shell repair frequency was 35.7%. Repairs in Trochonemella occur primarily in the larger size class, suggesting that a size refuge was achieved by this species. Low repair frequencies in L. trilineata suggest predation with a higher success rate or fewer encounters. This study demonstrates that the paradigm of a standardized low level of shell repair in Ordovician and Silurian gastropods is oversimplistic and a range of frequency rates can be expected.

Cytoskeletal Reorganization and Altered Phagocytotic Ability in Primary Cultures of Rainbow Trout Hemopoietic Tissue Exposed to Low-Level Ionizing Radiation

2005 ◽  
Vol 164 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Peter M. Olwell ◽  
David C. Cottell ◽  
Sharon Ní Shúilleabháin ◽  
Paola Maderna ◽  
Colin Seymour ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Ionizing Radiation ◽  
Primary Cultures ◽  
Cytoskeletal Reorganization ◽  
Low Level ◽  
Hemopoietic Tissue

Metal X-ray microanalysis in the olfactory system of rainbow trout exposed to low level of copper

1995 ◽  
Vol 83 (1) ◽  
pp. 77-86 ◽  
Author(s):  
A. Karyn Julliard ◽  
Diane Saucier ◽  
Liliane Astic
Keyword(s):  
Rainbow Trout ◽  
Olfactory System ◽  
X Ray ◽  
Low Level

Production and Movement of Juvenile Rainbow Trout (Salmo gairdneri) in a Headwater of Bothwell's Creek, Georgian Bay, Canada

1974 ◽  
Vol 31 (1) ◽  
pp. 117-121 ◽  
Author(s):  
D. Ross Alexander ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Great Lakes ◽  
Annual Production ◽  
Salmo Gairdneri ◽  
Ecological Disturbance ◽  
Georgian Bay ◽  
Juvenile Rainbow Trout ◽  
Total Annual Production ◽  
Calculated Ratio

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.

scholarly journals Comparison of Individual and Pooled Sampling Methods for Detecting Bacterial Pathogens of Fish

2005 ◽  
Vol 17 (4) ◽  
pp. 305-310 ◽  
Author(s):  
Sonia Mumford ◽  
Chris Patterson ◽  
Joy Evered ◽  
Ray Brunson ◽  
Jay Levine ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Bacterial Infections ◽  
Sampling Methods ◽  
Bacterial Pathogens ◽  
Yersinia Ruckeri ◽  
Fish Pathogens ◽  
Blue Book ◽  
Low Level ◽  
Pooled Samples ◽  
Positive Groups

Examination of finfish populations for viral and bacterial pathogens is an important component of fish disease control programs worldwide. Two methods are commonly used for collecting tissue samples for bacteriological culture, the currently accepted standards for detection of bacterial fish pathogens. The method specified in the Office International des Epizooties Manual of Diagnostic Tests for Aquatic Animals permits combining renal and splenic tissues from as many as 5 fish into pooled samples. The American Fisheries Society (AFS) Blue Book/US Fish and Wildlife Service (USFWS) Inspection Manual specifies the use of a bacteriological loop for collecting samples from the kidney of individual fish. An alternative would be to more fully utilize the pooled samples taken for virology. If implemented, this approach would provide substantial savings in labor and materials. To compare the relative performance of the AFS/USFWS method and this alternative approach, cultures of Yersinia ruckeri were used to establish low-level infections in groups of rainbow trout ( Oncorhynchus mykiss) that were sampled by both methods. Yersinia ruckeri was cultured from 22 of 37 groups by at least 1 method. The loop method yielded 18 positive groups, with 1 group positive in the loop samples but negative in the pooled samples. The pooled samples produced 21 positive groups, with 4 groups positive in the pooled samples but negative in the loop samples. There was statistically significant agreement (Spearman coefficient 0.80, P < 0.001) in the relative ability of the 2 sampling methods to permit detection of low-level bacterial infections of rainbow trout.

Growth dynamics of mosaic muscle fibres in fingerling rainbow trout (Salmo gairdneri) in relation to somatic growth rate

1980 ◽  
Vol 58 (9) ◽  
pp. 1535-1541 ◽  
Author(s):  
A. H. Weatherley ◽  
H. S. Gill ◽  
S. C. Rogers
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Fibre Diameter ◽  
Fork Length ◽  
Salmo Gairdneri ◽  
Muscle Fibres ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Rate Condition ◽  
Epaxial Muscle

We examined the effects of varying water temperature (5, 12, 20 °C), ration size (ad libitum, and 3–4% of dry body weight per day), and injection of bovine growth hormone, on the growth characteristics of the epaxial muscle in laboratory-reared rainbow trout. Although the experimental conditions resulted in differences in growth rate, condition factor (K = W/L3 × 102) and dry weight, we found that, below a fork length of 18–20 cm, an increase in the cross-sectional area of the epaxial muscle occurs mainly by the addition of new fibres. However, between 20 and 25 cm the increase evidently results mainly from an increase in diameter of existing fibres. The relationship between fibre diameter frequency and fork length is characterized, and the implications of this relationship in limiting growth of this species is discussed.

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