New Method for Ageing Chinook Salmon (Onchorhynchus tshawytscha) Using Dorsal Fin Rays, and Evidence if Its Validity

1986 ◽  
Vol 43 (8) ◽  
pp. 1588-1594 ◽  
Author(s):  
D. E. Chilton ◽  
H. T. Bilton

Age of spawning chinook salmon (Oncorhynchus tshawytscha) was estimated using a combination of thin cross-sections from the dorsal fin rays and scales. The latter were used when freshwater growth could not be interpreted from fin rays. Fish of known age were used when available. Results were compared with ages obtained from scales only. Due to scale resorption a significant proportion of the older fish ages was undetected using only scales. Determinations of freshwater age from fin rays and from scales were in agreement 88.5 ± 8.7 to 92.3 ± 7.2% at the 95% confidence level. Thus, the fin ray method provided virtually the same freshwater age as did the scale method. Also, fin rays provided quite acceptable estimation of ocean age. It is recommended that managers use a combination of scales and fin rays to estimate the total age of spawning chinook salmon.

1969 ◽  
Vol 26 (3) ◽  
pp. 633-638 ◽  
Author(s):  
R. J. Beamish ◽  
H. H. Harvey

The purpose of this study was to test the reliability of the scale method for determining the age of white suckers. To do so, an alternative method of "aging" was explored, using sections cut from the first four rays of the pectoral fin. Two hundred and fifty white suckers were tagged, and a piece of one pectoral fin was removed before they were released. A year later, 25 were recaptured, and the rays of the remaining pectoral fin were aged. Of the recaptures, 22 showed clearly the addition of one annulus.Having confirmed the fin-ray method, the age of another 157 suckers was determined by scales and fin rays and compared. The results indicated the scale method was reliable, in this population, until the fish reach an age of 5 years. Beyond 5 years there was not close agreement between scale and fin ages. After 8 years, age as determined by scales was invariably less than from fin rays, and sometimes was in error by as much as 5 years.


1977 ◽  
Vol 34 (9) ◽  
pp. 1305-1313 ◽  
Author(s):  
Richard J. Beamish ◽  
D. Chilton

Cross sections of the 4th–8th fin rays from the second dorsal fin provided reliable ages of lingcod (Ophiodon elongatus), although there was some difficulty interpreting the ages of 1- and 2-yr-old fish. Length was an acceptable indicator of age 1- and 2-yr-old fish. After a scale age of 5 or 6 yr, the scale annulus became difficult to identify. After age 7 or about 75–85 cm, fin-ray ages were older than scale ages. Some of the oldest fish averaged 8 yr older by the fin-ray method.Mature females attained much larger mean sizes than males of similar age, and there was considerable variation in size of similar-aged older fish. Key words: Age determination, fin rays, scales, Ophiodon elongatus, ageing errors.


1980 ◽  
Vol 37 (3) ◽  
pp. 534-544 ◽  
Author(s):  
K. H. Mills ◽  
R. J. Beamish

Fifteen populations of lake whitefish (Coregonus clupeaformis) were sampled to compare the fin-ray and scale aging techniques. There was good agreement between aging methods in fast growing populations, but usually fin-ray ages were larger than scale ages in slow-growing populations. The validity of each aging method was tested by comparing fin-ray and scale ages taken from three populations of whitefish when marked and when recaptured at least 1 yr later. When growth was rapid, recaptured fish formed annular marks on both fin-rays and scales. When growth was slower, annular marks were distinguished on fin-ray sections more often than on scales of recaptured fish. When growth was extremely poor, annular marks on scales of recaptured fish were rarely distinguishable, but still recognizable on the majority of fin-ray sections. When fin-ray ages were consistently larger than scale ages for a given population, fin-ray based estimates of annual survival were higher and growth slower than corresponding scale age based estimates. In general, the fin-ray method was more reliable than the scale method of aging lake whitefish.Key words: lake whitefish, age determination, scales, fin-rays, annual survival, growth


2018 ◽  
Vol 82 (3) ◽  
pp. 169
Author(s):  
Ronald Fricke ◽  
Daniel Golani ◽  
Brenda Appelbaum-Golani ◽  
Uwe Zajonz

The scorpionfish Scorpaena decemradiata n. sp. is described from off the coast of Israel in the Gulf of Aqaba, northern Red Sea. The new species is similar to S. porcus Linnaeus, 1758, but is characterized by dorsal fin spines XII, soft dorsal fin rays 10 (the last divided at base); pectoral fin rays 16, uppermost branched pectoral fin ray is the second; lacrimal with 2 spines over maxilla that point at nearly right angle from each other, the posterior pointing ventrally and slightly anteriorly; occipital pit well developed; anteriormost mandibular lateral-line pores small, separated; scales ctenoid; 59-62 scale rows in longitudinal series; scales absent on chest and pectoral fin base; and cirri developed over entire head and body, but no cirri on lower jaw. An updated checklist of the species of the genus Scorpaena Linnaeus, 1758 and a key to the species of the eastern Atlantic, Mediterranean Sea and Red Sea are presented.


Zootaxa ◽  
2019 ◽  
Vol 4551 (3) ◽  
pp. 275 ◽  
Author(s):  
KYOJI FUJIWARA ◽  
HIROYUKI MOTOMURA

The clingfishes Lepadichthys frenatus Waite 1904 and Lepadichthys misakius (Tanaka 1908) are both redescribed as valid species, although the latter has previously been regarded as a junior synonym of the former. Lepadichthys frenatus and L. misakius are easily distinguished from their congeners by the following combination of characters: 14–19 dorsal-fin rays; 12–14 anal-fin rays; disc size moderate, its length 15.1–20.8 % of standard length (SL); and dorsal, anal and caudal fins connected by membranes. Lepadichthys misakius can be distinguished from L. frenatus by having 25–28 (modally 26 or 27) pectoral-fin rays [vs. 27–29 (29) in L. frenatus]; the upper end of the gill membrane level with the 5th to 8th (usually 6th) pectoral-fin ray base in lateral view [vs. 6th to 8th (7th)]; the lower 8th to 11th (9th) pectoral-fin ray base attached to the disc base by membrane [vs. 10th to 12th (11th)]; 7–11 (9) gill rakers on each arch [vs. 11–14 (12)]; anterior, posterior and least interorbital widths 9.0–11.8 (mean 10.7), 13.4–16.9 (15.3) and 3.2–8.8 (6.2) % SL, respectively [vs. 8.4–10.2 (9.4), 12.1–14.7 (13.5) and 2.8–5.9 (4.8) % SL, respectively]; and NC2 (nasal canal pore) usually located between the anterior and posterior margins of the posterior nostril (vs. usually located before the posterior nostril anterior margin). Morphological changes with growth of the two species are described in detail and a lectotype designated for L. frenatus. 


Zootaxa ◽  
2018 ◽  
Vol 4531 (1) ◽  
pp. 95
Author(s):  
HARALD AHNELT ◽  
MICHAEL SAUBERER

Schindleria macrodentata sp. nov., a new species of the paedomorphic gobiid fish genus Schindleria, is described from the Malay Archipelago. The two specimens were collected in 1929 during the “Dana Expedition” in the Molucca Sea between Sulawesi and Halmahera islands (00°29′N, 125°54′E) (Indonesia) and in the Sulu Sea close to Panay Island (11°43’N, 121°43′E) (Philippines). The new species is characterized by a slender body (body depth at pectoral fin base 3.6–3.7 % of SL and at anal fin origin 3.9–4.8 % of SL), a long second dorsal fin (first dorsal fin absent) originating distinctly anterior to the origin of the anal fin (predorsal length 61.8–65.2 % of SL and preanal length 71.7–75.8 % of SL), a short tail (from anus to tip of longest caudal fin ray) (22.1 % of SL), 19–20 dorsal fin rays and 10 anal fin rays, first anal fin ray below 9th dorsal fin ray, few large, widely spaced teeth in the upper and the lower jaws (7 on the premaxilla and 6 on the dentary), an elongated pectoral radial plate (length 3.7–4.5 % of SL) and, in the caudal skeleton, a procurrent ray with an additional spiny process at its base. No distinct urogenital papilla and no pigmentation on body are developed. In this study we present three morphological traits until now not considered as diagnostic characters for Schindleria, the shape of the pectoral radial plate, the shape of the last procurrent caudal spine and the shape of the arch formed by the lower jaw. We also discuss the caudal-fin skeleton of Schindleria, a character developing beyond the larval stages. The record of S. macrodentata is the first of the genus Schindleria for Indonesia and, at more than 100 km distant to the next shore, it is the first offshore record of a Schindler's fish. 


1971 ◽  
Vol 28 (4) ◽  
pp. 553-558 ◽  
Author(s):  
L. S. Parsons ◽  
V. M. Hodder

Numbers of vertebrae, gill rakers, and of pectoral, anal, and dorsal fin rays of spring- and autumn-spawning Atlantic herring (Clupea harengus harengus Linnaeus) in 10 samples from the coastal waters of southwestern Newfoundland were compared. There was no significant difference (P > 0.05) between mean vertebral numbers of spring and autumn spawners. Mean numbers of gill rakers and of pectoral, anal, and dorsal fin rays were all higher (P < 0.01) for autumn spawners than for spring spawners with gill-raker and pectoral fin-ray numbers exhibiting the greatest degree of difference. It is suggested that the differences in fin-ray numbers between spring and autumn spawners are related to water temperatures during larval development and to differences in developmental rates of spring- and autumn-hatched larvae.


Zootaxa ◽  
2010 ◽  
Vol 2434 (1) ◽  
pp. 60 ◽  
Author(s):  
ADRIANA E. ALMIRÓN ◽  
JORGE R. CASCIOTTA ◽  
MARÍA DE LAS M. AZPELICUETA ◽  
MARCELO LOUREIRO
Keyword(s):  
Fin Ray ◽  

Astyanax stenohalinus Messner, 1962 is redescribed based on type material and new specimens collected in many localities of Argentina and Uruguay. This species is distinguished by a combination of the following characters: possession of hooks in all fins of males, teeth not expanded distally, two or three maxillary teeth, 37–39 perforated scales in the lateral series, 25–30 branched anal-fin rays, and anal-fin origin located before a vertical through last dorsal-fin ray insertions.


1982 ◽  
Vol 39 (12) ◽  
pp. 1664-1685 ◽  
Author(s):  
I-H. Ni

The distribution of Northwest Atlantic beaked redfishes, Sebastes mentella and S. fasciatus, has been confused for the past several decades. Sebastes fasciatus has been reported as having lower meristic counts than S. mentella. Meristic elements of 33 301 vertebrae, 22 622 anal fin ray, and 16 290 dorsal fin ray counts were utilized to examine the yearly, depth, and geographic variation of meristics in beaked redfishes. Data collected from specimens caught off West Greenland, Baffin Island, Labrador, Newfoundland, Quebec, and Nova Scotia were analyzed by 100-m-depth intervals. Temporal and depth variation were examined by the χ2-test of independence on meristic frequencies. Geographic variation was evaluated using the modes and mean values in the meristic frequency histograms. Cluster analysis of meristic frequencies displayed the dendrographic affinities and the distance matrix among division–depth blocks.Temporal variation indicated a mixture of vertebral frequency patterns which varied with depth and area. Depth variation and geographic clines were found for each of these meristic characters; the shallow and southern waters were dominated by counts of 29, 14–13, and 7 for vertebrae, dorsal fin rays, and anal fin rays, respectively, whereas deep and northern waters were dominated by 30, 15–14, and 8–9. These results suggested that S. fasciatus occurs on the Nova Scotian Shelf and Grand Bank whereas S. mentella is largely found in Baffin Bay, Labrador waters, and the Gulf of St. Lawrence. The common names of S. mentella and S. fasciatus are discussed. Additionally, five hypothetical stocks of beaked redfishes based on meristic patterns are proposed for management purposes.Key words: Sebastes mentela, S. fasciatus, redfish, meristic variation, distribution, cluster analysis


Zootaxa ◽  
2011 ◽  
Vol 2823 (1) ◽  
pp. 61 ◽  
Author(s):  
HEOK HEE NG ◽  
DANG KHANH HONG ◽  
NGUYEN VAN TU

Clarias gracilentus, a new Southeast Asian walking catfish species, is described from Phu Quoc Island (Vietnam) off the coast of southeastern Cambodia and from mainland southeastern Cambodia. The new species is a member of the C. nieuhofii species complex, and can be distinguished from congeners in the complex in having a combination of: head width 11.9–12.9% SL, distance between the occipital process and the base of the first dorsal-fin ray 5.3–8.4% SL, pectoral-fin length 8.5–10.1% SL, body depth at anus 8.2–11.7% SL, pelvic-fin length 4.3–5.5% SL, length of anal-fin base 60.0–63.9% SL, eye diameter 5.4–7.2% HL, interorbital distance 42.7–48.0% HL, occipital-process length 7.8–14.7% HL, 96–101 dorsal-fin rays, 84–89 anal-fin rays and 80–84 total vertebrae.


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