Determination of the age of brown and rainbow trout in a range of New Zealand lakes

1996 ◽  
Vol 47 (5) ◽  
pp. 749 ◽  
Author(s):  
E Graynoth
Keyword(s):  
Rainbow Trout ◽  
New Zealand ◽  
Frequency Analysis ◽  
Salmo Trutta ◽  
Juvenile Fish ◽  
Length Frequency ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Fin Rays ◽  
Juvenile Trout ◽  
Length Frequency Analysis

Brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) from eight New Zealand lakes were aged by length-frequency analysis and by examining otoliths, pectoral fin rays and scales. Bimonthly changes in the length frequency of age classes were used to age fish for their first 2 or 3 years of life. Growth rates were highest in spring and summer, when a single wide opaque band was laid down on otoliths and fin rays, followed by a narrow transparent band in winter. Age estimates from otoliths agreed with 94-97% of those from length-frequency methods and with the ages of 21 tagged fish. Otoliths were used to age fish up to 11 years old and were more accurate than fin rays and scales. Although fin rays could be used to age juvenile fish from Lake Coleridge, where there was 78-80% agreement between otolith and fin ray ages, they were of little value for older fish in Lake Alexandrina (28% agreement). Rainbow trout scales from all lakes were difficult to read because of indistinct annuli and the presence of false checks. Mature trout were also difficult to age owing to scale absorption and a cessation of scale growth. The degree of agreement between otolith and scale ages ranged from 83-84% for trout in Lake Coleridge to 32-38% for older rainbow trout in other lakes. This study supports the findings of other researchers that trout scales can provide inaccurate estimates of the age of trout in New Zealand and Australia. It is suggested that otolith examination, supported by length-frequency analysis of juvenile trout, be used to age trout from New Zealand lakes. In many cases, examination of otoliths will be cheaper and quicker than the release and later recapture of fin-clipped or tagged juvenile trout.

Growth rate estimates for New Zealand Rig (Mustelus lenticulatus)

1992 ◽  
Vol 43 (5) ◽  
pp. 1157 ◽  
Author(s):  
MP Francis ◽  
RICC Francis
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
Frequency Analysis ◽  
Growth Rates ◽  
Growth Curves ◽  
Combined Effects ◽  
Length Frequency ◽  
Total Length ◽  
Males And Females ◽  
Length Frequency Analysis

Growth rate estimates were obtained for New Zealand rig (Mustelus lenticulatus) by analysing length frequency and tag-recapture data. Rig (0+) sampled by set-net in Porirua and Pauatahanui Inlets grew from about 25-30 cm total length at birth to 46-49 cm at age of about 6 months. Samples of juvenile and adult rig trawled in Pegasus Bay and Hauraki Gulf suffered from under-representation of large adults, probably because of escapement. Growth curves derived from length-frequency analysis indicated that Pegasus Bay males matured at 5.0 years and had a minimum longevity of 12 years. Hauraki Gulf males and females matured at 3.7 and 4.7 years, respectively. Growth rates and ages at maturity fell within the ranges reported for other Mustelus species. Tagging data for South Island rig suggested that females grew faster than males. However, growth rate estimates from length-frequency analysis were 2.7-3.3 times greater than estimates from tagging data, probably because the latter were biased by the combined effects of tagging on growth and set-net mesh selectivity.

scholarly journals Rearing larvae and juveniles of rainbow trout with different amino acid nutrition

2020 ◽  
Author(s):  
V. Kondratiuk ◽  
Keyword(s):  
Amino Acids ◽  
Rainbow Trout ◽  
Amino Acid ◽  
Juvenile Fish ◽  
Control Group ◽  
Economic Optimization ◽  
Larvae And Juveniles ◽  
Experimental Fish ◽  
Juvenile Trout ◽  
High Level

The article considers the efficiency of using complete compound feeds with different levels of lysine and methionine in rearing larvae and juveniles of rainbow trout. The purpose of the experiment was to establish the effect of different amino acid levels in nutrition of juvenile trout on its productivity. For this purpose, five experimental groups were formed by the method of analogues. The experiment lasted 35 days and was divided into two periods: equalizing (5 days) and main (30 days). During the equalizing period, the experimental fish consumed feed of the control group. In the main period, the levels of lysine and methionine in experimental feeds for different experimental groups of trout ranged from 2.9 to 3.3% and from 0.95 to 3.15%, respectively. It is proved that increasing the content of lysine and methionine in feed for larvae and juveniles of rainbow trout to the levels of 3.2 and 1.1%, respectively, promotes increase in their weight by 10.7% (p <0.01) and growth intensity - by 6.4-11.1%, while further increase in these amino acids content in the feed reduces the productivity of fish. Polynomial equations for determining the juvenile fish weight at any stage of rearing at a high level of determination for each of the experimental groups have been calculated. It was found that with an increase in the content of lysine and methionine in feed to the levels of 3.2 and 1.1%, respectively, reduces feed costs per 1 kg of weight gain in trout larvae and juveniles by 4.1%, and a further increase in levels of these amino acids to 3.3 and 1.15%, respectively, increase this index by 1.1%. The experimental fish survival ranged from 83.9 to 85.1%. In the production of trout according to the criteria of maximum productivity and to the economic optimization criteria, it is recommended to use complete feed with the level of lysine - 3.2% and methionine - 1.1% for feeding trout larvae and juveniles.

scholarly journals DINAMIKA POPULASI LOBSTER PASIR (Panulirus homarus Linnaeus, 1758) DI PERAIRAN PALABUHANRATU, JAWA BARAT

2018 ◽  
Vol 23 (3) ◽  
pp. 215 ◽  
Author(s):  
Zairion Zairion ◽  
Nefi Islamiati ◽  
Yusli Wardiatno ◽  
Ali Mashar ◽  
Rudi Alek Wahyudin ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Spiny Lobster ◽  
Total Sample ◽  
Optimum Level ◽  
Length Frequency ◽  
Recruitment Pattern ◽  
Exploitation Rate ◽  
Lobster Fishery ◽  
Average Size ◽  
Length Frequency Analysis

Dinamika populasi merupakan aspek penting sebagai dasar pengelolaan perikanan dan informasi tentang aspek tersebut pada lobster pasir masih minim di perairan Palabuhanratu. Tujuan penelitian ini adalah mengkaji aspek pertumbuhan, pola rekrutmen, mortalitas dan laju eksploitasi lobster pasir (Panulirus homarus) di perairan Palabuhanratu. Penelitian ini dilakukan periode Juni 2015-Mei 2016 dengan metode sensus. Lobster pasir hasil tangkapan jaring insang dasar dengan jumlah total sampel 483 ekor mempunyai panjang karapas antara 28-100 mm. Pola pertumbuhan berdasarkan hasil regresi linear memperlihatkan allometrik negatif. Hasil analisis menggunakan metode ELEFAN I (Electronic Length Frequency Analysis) menunjukan koefisien pertumbuhan lobster pasir jantan (K = 0,29 per tahun), lebih kecil dibandingkan dengan betina (K = 0,40 per tahun). Rekrutmen terindikasi dua puncak dalam setahun: yaitu pada Februari-Mei dan September-Oktober). Laju mortalitaskarena penangkapan (F) mencapai 1,9-2,2 kali laju mortalitas alami (M). Nilai Lc<Lrmemperlihatkan lobster pasir sudah tertangkap sebelum mencapaiukuran rata-rata mengerami telur atau ukuran kematangan reproduktif. Laju eksploitasi lobster pasir mencapai 32-38% di atas laju eksploitasi optimum, sehingga lobster pasir sudah mengalamieksploitasi yang berlebih.Population dynamics is an important aspect as basic of fisheries management and little information of this aspect for spiny lobster fishery in Pelabuhanratu waters. This research aims to evaluate of growth aspects, recruitment pattern, mortality, and exploitation rate of scalloped spiny lobster (Panulirus homarus) in Palabuhanratu waters. This research was conducted in June 2015 until May 2016 using census method. The size of P. homarus captured using bottom gill-net with total sample 483 specimen was between 28-100 mm carapace lengths (CL). Linear regression showed that growth pattern was negative allometric. The growth coefficient of male (K = 0.29 per year) was found smaller than female (K = 0.40 per year) based on ELEFAN I (Electronic Length Frequency Analysis) method. Recruitment seems to be accrued twice peaks a year (February to May and September to October) and the highest was at February to May. Fishing mortality (F) reached 1.9 to 2.2 times of natural mortality (M). The LcÂLr value showed that female has been caught before reached the average size of bearing eggs or reproductive maturity size. The exploitation rate of spiny lobsters reaches 32-38% above optimum level. This study suggests that the spiny lobster fishery in Palabuhanratu in the state of overexploitation.

scholarly journals Growth and age composition of northern shrimp Pandalus eous estimated by multiple length frequency analysis

2014 ◽  
Vol 80 (4) ◽  
pp. 665-678 ◽  
Author(s):  
Hiroshi Yamaguchi ◽  
Yoko Goto ◽  
Noboru Hoshino ◽  
Kazushi Miyashita
Keyword(s):  
Frequency Analysis ◽  
Length Frequency ◽  
Age Composition ◽  
Northern Shrimp ◽  
Length Frequency Analysis
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