Influence of light on early development and meristic characters in the rainbow trout, Salmo gairdneri Richardson

1969 ◽  
Vol 47 (4) ◽  
pp. 631-637 ◽  
Author(s):  
H. R. MacCrimmon ◽  
Wen-Hwa Kwain
Keyword(s):  
Rainbow Trout ◽  
Light Intensity ◽  
Metabolic Rate ◽  
Early Development ◽  
Salmo Gairdneri ◽  
Artificial Light ◽  
Meristic Characters ◽  
Fin Rays ◽  
Test Light ◽  
Pelvic Fin

Initial mortality of newly fertilized rainbow trout eggs incubated in artificial light increased with intensity. The mortality among eyed eggs exposed to the same set of conditions was comparatively low regardless of intensity. Mortality, time to hatch, metabolic rate, and the number of vertebrae formed correlated positively with visible light intensity but only during the pre-eyed stage of incubation. By contrast, the numbers of dorsal and anal fin rays were affected by light intensity during the posteyed incubation period, the greatest number of rays on these fins occurring in fish incubated at light intensity of 10 lux. The numbers of pectoral and pelvic fin rays were constant at all test light intensities. Further research is imperative if the importance of light as an environmental factor in the early development of fish is to be understood.

Temperature Effects on Mercury Accumulation, Toxicity, and Metabolic Rate in Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (4) ◽  
pp. 485-492 ◽  
Author(s):  
J. C. MacLeod ◽  
E. Pessah
Keyword(s):  
Rainbow Trout ◽  
Metabolic Rate ◽  
Mercuric Chloride ◽  
Accumulation Rate ◽  
Chloride Concentration ◽  
Fish Muscle ◽  
Salmo Gairdneri ◽  
Mercury Toxicity ◽  
Time To Death ◽  
Magnification Factors

Mercury toxicity in rainbow trout fingerlings was related to temperature and chemical formulation of the mercury. At 10 C, the 24-hr TLm concentration (median tolerance limit) for mercuric chloride (HgCl2) was approximately 30 times that for phenyl mercuric acetate (PMA). The 96-hr TLm values for mercuric chloride at 5, 10, and 20 C were 0.40, 0.28, and 0.22 mg Hg/liter. The velocity of mortality, (V = reciprocal of time to death in hours), was linearly related to temperature. For a mercuric chloride concentration of 0.5 mg Hg/liter, V =.002 +.0023t, where t = temperature in centigrade degrees.Temperature also affected accumulation rate of mercury in the fish muscle. At 5, 10, and 20 C a mercuric chloride concentration of 0.1 mg Hg/liter in the water produced biological magnification factors (conc. in fish ÷ conc. in water) of 4, 10, and 22 ×, respectively, PMA produced higher magnification factors of 80–100 × at 10 C.Active metabolic rate, though increased by higher temperatures, was depressed by mercuric chloride, and higher temperatures augmented the depressant effect.

The Species of Lebetus [Teleostei: Gobiidae]

1971 ◽  
Vol 51 (4) ◽  
pp. 771-776 ◽  
Author(s):  
P. J. Miller
Keyword(s):  
Early Development ◽  
Alternative View ◽  
Sexually Dimorphic ◽  
Meristic Characters ◽  
The North ◽  
North Eastern ◽  
Fin Rays ◽  
Dimorphic Species ◽  
Immature Fish ◽  
Recognition Of Another

The north-eastern Atlantic gobiid genus Lebetus Winther, 1877, was formerly believed to contain two species, Lebetus scorpioides (Collett, 1874) and L. orca (Collett, 1874). These have been subsequently shown to represent females (and immature fish) and males respectively of a single, sexually dimorphic species whose valid name is L. scorpioides. The discovery of two forms of Lebetus postlarvae, differing in meristic characters, fin growth, and pigmentation, is shown not to affect this conclusion but to suggest provisional recognition of another species, L. guilleti (Le Danois, 1913), with fewer anal fin-rays (A I/5–6) and vertebrae (25–26) than L. scorpioides (A I/7–8; vertebrae 27-29). A key and limited synonymy for the species is provided. As a possible alternative view it is suggested that relatively high summer sea-temperatures during early development of L. scorpioides in certain areas may produce the lower meristic features of L. guilleti.

scholarly journals Meristic and Morphometric Variations of Barred Spiny EEL Macrognathus pancalus Populations from Bangladeshi Freshwaters: An Insight Into Landmark-Based Truss Network System

2019 ◽  
Vol 77 (1) ◽  
pp. 7-18
Author(s):  
Md. Sarower-E-Mahfuj ◽  
Ambia Khatun ◽  
Puja Boidya ◽  
Md. Abdus Samad
Keyword(s):  
Network System ◽  
Effective Management ◽  
Meristic Characters ◽  
Lower Jaw ◽  
Meristic Counts ◽  
Fin Rays ◽  
Univariate Statistics ◽  
Two Populations ◽  
Insight Into ◽  
Pelvic Fin

Abstract The present research focuses to examine the meristic and landmark-based morphometric variations of barred spiny eel Macrognathus pancalus from four populations namely Dhakuria beel, Jessore (DBJ); Bohnni boar, Gopalgonj (BBG); the Arial kha river, Madaripur (AKRM) and the Nabaganga river, Jhenidah (NRJ) in Bangladeshi freshwaters. Six meristic counts were compared among four populations and significant differences were observed in number of caudal fin rays and number of pelvic fin rays in all meristic characters. The truss protocol was used in the present study based on six general morphometrics and fifteen truss measurements. Univariate statistics showed that five (standard length (SL), upper jaw length (UJL), lower jaw length (LJL), head depth (HD) and inter orbital (IO)) of six morphometric and eleven truss networks (viz. 2-3, 3-4, 5-6, 6-7, 7-8, 1-8, 2-8, 3-8, 3-7, 4-7 and 5-7) among fifteen truss measurements differed significantly. Cannonical discriminate function analyses were conducted among samples and the populations were fully intermingled. Pooled within-group correlation showed morphometric and landmark measurements; the first discriminant function (DF) accounted for 79%, the second DF accounted for 15.9% and third DF accounted for 5.1% of group variability. An euclidian dendrogram was prepared based on morphometric and truss measurements in four populations, where two clusters were mainly formed, in which first cluster formed by NRJ population was fully separated, and the second cluster was formed by two populations of AKRM and DBJ. Additionally, a subcluster BBG was formed with AKRM. On the basis of morphometric and truss measurements, 68.8%, 83.6%, 55.6% and 80% of original grouped cases were correctly classified in NRJ, AKRM, DBJ and BBG, respectively. These results specify the presence of different stocks of fish from four aquatic habitats. This study is highly significant for proper conservation and effective management of M. pancalus populations as well as for the scientific community for further research.

Further Observations on the Response of Rainbow Trout, Salmo gairdneri, to Overhead Light

1969 ◽  
Vol 26 (12) ◽  
pp. 3233-3237 ◽  
Author(s):  
Wen-hwa Kwain ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Artificial Light ◽  
Significant Preference ◽  
Minimum Light ◽  
Light Minimum ◽  
Overhead Light

The response of rainbow trout (Salmo gairdneri Richardson) to overhead light changed with the growth of the fish. No response was evident until the age of 7 months, after which the response became more pronounced with age. Trout exhibited a significant preference for the darkest chamber when given a choice of five intensities of artificial light. Minimum light threshold for 10-month-old fish was between 0.01 and 0.005 lux. However, 24-month-old fish had a lower level of light threshold between 0.005 and 0.001 lux.

Age and Vision as Factors in Bottom Colour Selection by Rainbow Trout, Salmo gairdneri

1969 ◽  
Vol 26 (3) ◽  
pp. 687-693 ◽  
Author(s):  
Wen-hwa Kwain ◽  
Hugh R. MacCrimmon
Keyword(s):  
Rainbow Trout ◽  
Light Intensity ◽  
Visible Light ◽  
Total Darkness ◽  
Salmo Gairdneri ◽  
Colour Discrimination ◽  
Significant Preference ◽  
Light Intensities ◽  
Behavioural Patterns ◽  
Normal Fish

Rainbow trout exposed in a circular tank to a choice of black or white bottom at a light intensity of 10−2 lux were randomly distributed until the age of 14 months at which time a significant preference for black began and became more pronounced with increasing age.Groups of fish (18–24 months of age) with normal eyes, without eye lenses, and lacking eyes, were held in total darkness and at 10−2, 10, and 200 lux. In total darkness all groups were randomly distributed and quiescent. Fish without eye lenses selected black at all visible light intensities and acted similarly to normal fish at 10−2 lux. Fish lacking eyes were randomly distributed and more-or-less inactive at all intensities.The eye is essential for bottom colour discrimination and behavioural patterns occurring in normal trout exposed to different light intensities.

Responses of meristic characters in chum salmon (Oncorhynchus keta) to temperature changes during development

1989 ◽  
Vol 67 (3) ◽  
pp. 596-600 ◽  
Author(s):  
Clyde B. Murray ◽  
Terry D. Beacham
Keyword(s):  
Chum Salmon ◽  
Oncorhynchus Keta ◽  
Meristic Characters ◽  
Gill Rakers ◽  
Temperature Changes ◽  
Chum Salmon Oncorhynchus Keta ◽  
Fin Ray ◽  
Fin Rays ◽  
Eye Pigmentation ◽  
Pelvic Fin

Variability in the number of dorsal, anal, caudal, pectoral, and pelvic fin rays, vertebrae, and gill rakers was examined in four populations of chum salmon (Oncorhynchus keta) transferred from 8 to 2 °C at various stages of embryonic development. Late transfers at complete eye pigmentation produced more gill rakers than transfers earlier in development. Transfers at completion of epiboly and initial eye pigmentation produced fewer vertebrae than earlier or later transfers. Stage of transfer had no significant effect on fin ray counts. Vertebral responses differed among families. Genotype–environment interactions produce meristic phenotypes that are presently difficult to predict.

Effect of DDT on Discriminating Ability of Rainbow Trout (Salmo gairdneri)

1975 ◽  
Vol 32 (6) ◽  
pp. 785-788 ◽  
Author(s):  
Patricia G. McNicholl ◽  
W. C. Mackay
Keyword(s):  
Rainbow Trout ◽  
Light Intensity ◽  
Salmo Gairdneri ◽  
Discriminating Ability

Rainbow trout (Salmo gairdneri) trained to discriminate between a bright (723 lx) and a dim (22 lx) light were tested to determine the minimum difference in light intensity they could distinguish before and 71 h after being given DDT orally at 0, 30, 50, and 80% of the LD50 dose. Discriminating ability decreased linearly with increased dose, while performance and retention were unaffected.

Use of Overhead Cover by Rainbow Trout Exposed to a Series of Light Intensities

1966 ◽  
Vol 23 (7) ◽  
pp. 983-990 ◽  
Author(s):  
Hugh McCrimmon ◽  
Wen-Hwa Kwain
Keyword(s):  
Rainbow Trout ◽  
Light Intensity ◽  
Positive Response ◽  
Total Darkness ◽  
Salmo Gairdneri ◽  
Light Intensities

Fingerling and yearling trout (Salmo gairdneri Richardson) responded differently when exposed to a series of artificial daylight illuminations. Fingerling trout showed no apparent response to the overhead cover, being randomly distributed at all light intensities. Yearling trout, except in total darkness, exhibit a positive response to the overhead cover, but their pattern of behaviour differed with the light intensity and the positioning of the cover.

scholarly journals MURAT NEHRI (PALU-ELAZIĞ)’NDE YAŞAYAN CAPOETA TRUTTA (HECKEL, 1843) TÜRÜNÜN BAZI MERISTIK VE MORFOMETRIK ÖZELLIKLERI

2020 ◽  
Vol 15 (4) ◽  
pp. 155-162
Author(s):  
Ebru İfakat Özcan
Keyword(s):  
Body Height ◽  
Pectoral Fin ◽  
Meristic Characters ◽  
Morphometric Measurements ◽  
High Positive Correlation ◽  
Morphometric Characters ◽  
Total Length ◽  
Fish Samples ◽  
Fin Rays ◽  
Pelvic Fin

In the present study, some meristic and morphometric characteristics of 66 Capoeta trutta (Heckel, 1843) fish samples collected from Murat River (Palu-Elazığ) were examined. The samples were immediately preserved with ice and fixed with 5% formaldehid on arrival in the laboratory. Metric measurements were carried out with 0.01 mm sensitive calipers. Meristic characters were counted as number of the dorsal fin rays, number of the anal fin rays, number of the pelvic fin rays, number of the pectoral fin rays, number of scales on the lateral line and number of the pharyngeal teeth. The morphometric characters were measured as total length, fork length, standard length, predorsal length, postdorsal length, caudal peduncle length, body width, body height, snout length, head length, head width, eye diameter, mouth width, intertorbital length, distance between pelvic fin and anal fin, distance between pelvic fin and pectoral fin. Morphometric measurements as total length percentage and total length regression models and determination coefficients (r2) were calculated. Generally, a significant, high, positive correlation was found between total length and morphometric measurements (r2= 0.70-0.92, p<0.01).

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