Small Scale Laboratory Culture of the Ormer, Haliotis Tuberculata

Author(s):  
Ikuo Hayashi

A simple aquarium system was used to keep large ormers collected from the wild and to rear juveniles from fertilization up to age one year. Spawning was induced by exposure to u.v. irradiated sea water and counts made of gamete production. Repeated spawning was observed in males and from egg counts it was inferred that females also undergo repeat spawning in the wild.Juvenile ormers were reared on simple collectors up to 4 mm shell length and later in open mesh cages. There was large variation in growth rate between individuals among the juvenile ormers. After one year shell lengths varied in the range 6·2–21·o mm.Twenty-three adult ormers (shell length 40·4–93·6 mm) were reared for eight months in a tank with a concrete shelter. The smaller ormers remained under the shelter much more than the larger ones, some of which adopted a permanent position outside the shelter. In the study period growth was greater in the smaller specimens (less than 70 mm shell length) than in the larger ones.

Author(s):  
Ikuo Hayashi

A simple aquarium system was used to keep large ormers collected from the wild and to rear juveniles from fertilization up to age one year. Spawning was induced by exposure to u.v. irradiated sea water and counts made of gamete production. Repeated spawning was observed in males and from egg counts it was inferred that females also undergo repeat spawning in the wild.Juvenile ormers were reared on simple collectors up to 4 mm shell length and later in open mesh cages. There was large variation in growth rate between individuals among the juvenile ormers. After one year shell lengths varied in the range 6·2–21·o mm.Twenty-three adult ormers (shell length 40·4–93·6 mm) were reared for eight months in a tank with a concrete shelter. The smaller ormers remained under the shelter much more than the larger ones, some of which adopted a permanent position outside the shelter. In the study period growth was greater in the smaller specimens (less than 70 mm shell length) than in the larger ones.


1995 ◽  
Vol 46 (3) ◽  
pp. 571 ◽  
Author(s):  
DC McNamara ◽  
CR Johnson

Growth of ass's ear abalone (Haliotis asinina) was measured in situ (mark-recapture of adults) and in aquaria (juveniles) on Heron Reef, Queensland. A growth curve (y = 4.27L2.03 e-u, where y is the growth rate, L is the shell length, and u = 0.27L0.88) fitted to these data indicated a sigmoidal age-length relationship. It is estimated that H. asinina may grow from 2 mm to 35.6 mm in shell length in six months and 55.0 mm in one year. These growth estimates are consistent with temporal shifts in the size-frequency distributions of juveniles in the field. Peak growth rates, estimated at over 120 mm year-1 in young abalone (approximately 3-4 months of age), are the highest recorded for any abalone species.


2018 ◽  
Vol 13 (1) ◽  
pp. 39
Author(s):  
Fitriyah Husnul Khotimah ◽  
Gusti Ngurah Permana ◽  
Ibnu Rusdi ◽  
Bambang Susanto

Masalah utama yang umum terjadi pada produksi benih abalon adalah kematian yang tinggi (> 90%) setelah abalon menempel pada plate pemeliharaan. Penggunaan pakan dalam bentuk tepung untuk mengganti diatom sebagai pakan postlarva beberapa spesies ikan, udang, dan abalon sudah dilakukan. Penelitian ini bertujuan untuk mendapatkan jenis pakan dalam bentuk tepung yang sesuai dan efektif untuk mendukung sintasan dan pertumbuhan larva abalon Haliotis squamata. Percobaan terdiri atas lima perlakuan pakan pada pemeliharaan larva abalon yaitu tepung Spirulina sp., Ulva sp., Chaetoceros sp., Gracilaria sp., dan diatom (kontrol). Masing-masing perlakuan terdiri atas empat ulangan. Pakan berupa tepung yang digunakan pada masing-masing perlakuan, terlebih dahulu dicampur merata dengan larutan tepung agar (7,5 mg/mL dalam air laut; suhu 40°C) dengan konsentrasi tepung 40 mg/mL larutan agar. Pemberian pakan dilakukan setiap tiga hari dengan cara menyemprotkan larutan pakan pada permukaan plate pemeliharaan larva. Penelitian dilakukan selama 30 hari. Hasil penelitian menunjukkan bahwa sintasan larva abalon yang diberi pakan tepung Spirulina sp. paling tinggi dan berbeda nyata (P<0,05) dengan yang diberi diatom, tepung Chaetoceros sp., dan Ulva sp., yaitu masing-masing 81,49%; 79,25%; 76,57%; dan 76,46%; tetapi tidak berbeda nyata dengan yang diberi pakan tepung Gracilaria sp. 81,37% (P>0,05). Laju pertumbuhan harian panjang cangkang larva abalon tertinggi diperoleh pada larva yang diberi pakan tepung Gracilaria sp. (203,81 ± 1,23 µm/hari) dan Spirulina sp. (205,59 ± 1,71 µm/hari). Nilai laju pertumbuhan harian panjang cangkang larva abalon yang paling rendah dijumpai pada larva yang diberi pakan tepung Ulva sp. (146,07 ± 1,73 µm/hari).The most common problem in abalone seed production is the high mortality occurrence (> 90%) after postlarvae settlement to the rearing plates. The use of microparticle diets to replace the natural feed of postlarval has been performed on various species of fish, shrimp, and abalone. This research aims to determine the most effective and suitable powder-based feed to support the survival and growth of abalone Haliotis squamata larvae. The experiments consisted of five feed treatments, i.e., Spirulina sp., Ulva sp., Chaetoceros sp., and Gracilaria sp. Flour, and diatoms (as control). Each treatment had four replicates. The powder-based feed used in each treatment was firstly mixed with a solution of agar powder (7.5 mg/mL sea water, 40°C) with a concentration of 40 mg of flour/mL of agar solution. Feeding was done every three days by spraying the feed solution onto the surface of the larval rearing plate. The study was conducted for 30 days. The results showed that survival rate of abalone larvae fed with Spirulina sp. flour was the highest and significantly different (P<0.05) compared with those given diatoms, Chaetoceros sp. and Ulva sp. flours, which were 81.49%, 79.25%, 76.57%, and 76.46%, respectively, and not significantly different from those fed with Gracilaria sp. 81.37% (P>0.05). The highest daily growth rate of the shell length of abalone larvae was achieved by larvae fed with Gracilaria sp. (203.81 ± 1.23 ¼m/day) and Spirulina sp. flours (205.47 ± 1.71 µm/day). The lowest daily growth rate of shell length was found on abalone larvae fed with Ulva sp. flour (146.07 ± 1.73 µm/day).


1998 ◽  
Vol 64 (5) ◽  
pp. 1780-1785 ◽  
Author(s):  
Victoria J. Evans ◽  
Hemachandra Liyanage ◽  
Adriana Ravagnani ◽  
Michael Young ◽  
Eva R. Kashket

ABSTRACT The wild-type strain of Clostridium beijerinckii NCIMB 8052 tends to degenerate (i.e., lose the ability to form solvents) after prolonged periods of laboratory culture. Several Tn1545 mutants of this organism showing enhanced long-term stability of solvent production were isolated. Four of them harbor identical insertions within the fms (def) gene, which encodes peptide deformylase (PDF). The C. beijerinckii fms gene product contains four diagnostic residues involved in the Zn2+ coordination and catalysis found in all PDFs, but it is unusually small, because it lacks the dispensable disordered C-terminal domain. Unlike previously characterized PDFs fromEscherichia coli and Thermus thermophilus, theC. beijerinckii PDF can apparently tolerate N-terminal truncation. The Tn1545 insertion in the mutants is at a site corresponding to residue 15 of the predicted gene product. This probably removes 23 N-terminal residues from PDF, leaving a 116-residue protein. The mutant PDF retains at least partial function, and it complements an fms(Ts) strain of E. coli. Northern hybridizations indicate that the mutant gene is actively transcribed in C. beijerinckii. This can only occur from a previously unsuspected, outwardly directed promoter located close to the right end of Tn1545. The Tn1545 insertion in fms causes a reduction in the growth rate of C. beijerinckii, and, associated with this, the bacteria display an enhanced stability of solvent production. The latter phenotype can be mimicked in the wild type by reducing the growth rate. Therefore, the observed amelioration of degeneration in the mutants is probably due to their reduced growth rates.


Author(s):  
Mohd Baharudin Ridzuan ◽  
Zawawi Daud ◽  
Amir Detho ◽  
Halizah Awang ◽  
Mohd Arif Rosli ◽  
...  

Paleobiology ◽  
1981 ◽  
Vol 7 (4) ◽  
pp. 469-480 ◽  
Author(s):  
J. Kirk Cochran ◽  
Danny M. Rye ◽  
Neil H. Landman

The growth rate of Nautilus pompilius in its natural environment has been determined from radioactive disequilibrium between 210Pb (half-life 22.3 yr) and its granddaughter 210Po (half-life 138 d) in septa of two juvenile specimens. 210Pb and 210Po data from the most recently formed shell material of both specimens indicate that 210Pb from sea water is incorporated into septa during septal formation and 210Po is excluded. Therefore the 210Po/210Pb activity ratio serves as a chronometer to estimate the age of each septum and the time between formation of septa. In the specimens studied the average time between sucessive points in septal deposition is 75 d for the nine most recent septa of one specimen and 23 d for the six most recent septa of the other specimen. These different growth rates, if representative of the ontogeny of each animal, suggest that the timing of septal deposition probably is dependent on the rate of shell and tissue growth coupled with buoyancy requirements and is not a unique period for all Nautilus. The habitat and ontogeny of Nautilus may be inferred from the pattern of stable isotopes of oxygen and carbon in the septa. Both specimens show a pronounced break in δ18O from nearly uniform light values in the first seven septa to heavier values (∼1%) after the seventh septum. We interpret this break to correspond to the hatching of Nautilus. A temperature (i.e. water depth) interpretation of the δ18O data for septa after the eighth is complicated by a positive correlation between δ18O and δ13C. This may reflect horizontal migration of the animal or a kinetically controlled fractionation of carbon and oxygen isotopes during septal formation.


2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
A. S. Ajala ◽  
A. Gana

Rice is the most economically important food crop in many developing countries and has also become a major crop in many developed countries where its consumption has increased considerably. It has become necessary to meet the demand of the world’s current population growth rate, and the least costly means for achieving this aim is to increase rice productivity, wherever possible. The main challenges encountered by rice processors in Nigeria are to find appropriate solutions for quality rice processing. Therefore this work provides basic information about the challenges of rice processing and focuses on the challenges faced by the small scale rice processors and reasons for continuous rice importation with a view to guiding decision-making to be self-sufficient in rice production, thereby making some improvement in Nigerian economy.


Author(s):  
Ana L. Ibáñez ◽  
Diana Y. Montero

This study documents the presence of crypsis in Mugil curema juveniles under laboratory culture. Initially, the juveniles were located in one brown tank (BT1), later almost half of the individuals were placed in a white tank (WT) where they showed a pigmentation change to white. After being moved to another brown tank (BT2), the juveniles changed to their brown original colour, but kept a few small white spots on the dorsal axis of the body. The ventral head melanophore pattern also changed in the white specimens. Temperature (°C), oxygen (mg l−1) and Illuminance light (Lux m−2), total length (mm) and total weight (g) were determined by tank. Chromaticity was measured in L*(relative luminance) a*(measurement relating to the redness or greenness of the light) b*(measurement relating to the yellowness or blueness of the light) coordinates where all three values are required to completely describe an object’s colour. One-way ANOVA showed no differences for temperature, oxygen and illuminance light among tanks. Length and weight were similar for BT1 and WT but both were different from BT2. The white juveniles depicted similar L* as the WT background as well as the dorsal area of the brown pigmentation and converted juveniles to the brown tanks BT1 and BT2, respectively. Therefore, the fish's body relative luminance matches the background. To our knowledge this behaviour has not been reported before for any fish mullet either cultured or living in the wild.


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