scholarly journals PERKEMBANGAN AWAL LARVA KERAPU KERTANG (Epinephelus lanceolatus)

2016 ◽  
Vol 2 (3) ◽  
pp. 365
Author(s):  
Philip Teguh Imanto ◽  
Made Suastika

Observasi pada larva kerapu kertang (E. lanceolatus) dilaksanakan di Balai Besar Riset Perikanan Budidaya Laut (BBRPBL), Gondol-Bali, untuk mengumpulkan informasi dasar tentang perkembangan awal morfologi larva yang penting untuk menunjang keberhasilan pembenihannya. Larva berasal dari telur hasil pemijahan yang dirangsang dengan hormon (di Taiwan) dan ditransportasikan segera setelah menetas (D-0) melalui transportasi udara ke laboratotium pembenihan BBRPBL, Gondol. Pengamatan dilakukan dengan memanfaatkan fasilitas tangki 500 L dengan sistem air resirkulasi. Dari data yang dihimpun diketahui bahwa rata-rata panjang total larva (D-1) 2,48 mm; D-8 3,17 mm; dan tumbuh dengan cepat mencapai 10,79 mm pada D-19. Kuning telur larva yang berumur sehari (D-1) rata-rata bervolume 150,3 x 10-4 mm3 dan pada hari ketiga terserap 42,61% dan habis pada hari keempat (D-4). Butir minyak larva D-1 sebesar 41,9 x 10-4 mm3 dan masih tersisa sebesar 0,34 x 10-4 mm3 sampai dengan D-6. Mulut larva diperhitungkan sudah mencapai lebar sebesar 200 μm pada D-2. dan mampu untuk memangsa rotifer sejalan dengan pigmentasi mata yang mulai terjadi pada D-2 dan sempurna pada D-3. Dari analisis pertumbuhan terjadi titik belok (flexion point) pada D-8 dan setelah itu terjadi kurva pertumbuhan yang cepat y= 0,6747x-2,5508. Berdasarkan hasil observasi tersebut maka pemberian pakan awal untuk larva kerapu kertang sudah bisa diberikan pada D-2 akhir (sore), pada D-8 komposisi pakan alami sudah harus diubah dengan memberikan pakan yang lebih besar dan bernutrisi tinggi.Observation on early development of E. lanceolatus larvae have been conducted in laboratory condition at Gondol Research Institute for Mariculture (GRIM) Bali; the purpose was to gain basic data mainly on the larval development stage to support both larval rearing and aquaculture technique of this species. The larvae from egg were produced by induced spawning technique and transported on D-0 to GRIM. Observation have been conducted in 500 L tank with recirculation (close system) facilities. Morphological data showed that the total length of larvae on D-1 was 2.48 mm, became 3.17 mm on D-8 and grew faster to reach 10.75 mm on D-19. The volume of yolk on D-1 was 150.3 x 10-4 mm3 and was absorbed 42,61% on D-3 and finished on D-4. Oil globule on D-1 was 41.9 x 10-4 mm3 and still remained 0.34 x 10-4 mm3 on D-6. The mouth width of larval was 200  μm on D-2 and able to catch and feed rotifer in line with eye pigmentation where started from D-2 (in the afternoon) and became completed on D-3 early morning. The flexion point was on D-8 with faster growth with curve at y= 0.6747x–2.5508 afterward. Based on this result, there are some key points, first feeding for king grouper larvae might start on late D-2, and on D-8 larval feed should be changed with bigger size and more nutritious feed.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nwamaka Oluchukwu Akpodiete ◽  
Frédéric Tripet

Abstract Background Malaria vector control approaches that rely on mosquito releases such as the sterile insect technique (SIT) and suppression or replacement strategies relying on genetically modified mosquitoes (GMM) depend on effective mass production of Anopheles mosquitoes. Anophelines typically require relatively clean larval rearing water, and water management techniques that minimise toxic ammonia are key to achieving optimal rearing conditions in small and large rearing facilities. Zeolites are extensively used in closed-system fish aquaculture to improve water quality and reduce water consumption, thanks to their selective adsorption of ammonia and toxic heavy metals. The many advantages of zeolites include low cost, abundance in many parts of the world and environmental friendliness. However, so far, their potential benefit for mosquito rearing has not been evaluated. Methods This study evaluated the independent effects of zeolite and daily water changes (to simulate a continuous flow system) on the rearing of An. coluzzii under two feed regimes (powder and slurry feed) and larval densities (200 and 400 larvae per tray). The duration of larval development, adult emergence success and phenotypic quality (body size) were recorded to assess the impact of water treatments on mosquito numbers, phenotypic quality and identification of optimal feeding regimes and larval density for the use of zeolite. Results Overall, mosquito emergence, duration of development and adult phenotypic quality were significantly better in treatments with daily water changes. In treatments without daily water changes, zeolite significantly improved water quality at the lower larval rearing density, resulting in higher mosquito emergence and shorter development time. At the lower larval rearing density, the adult phenotypic quality did not significantly differ between zeolite treatment without water changes and those with daily changes. Conclusions These results suggest that treating rearing water with zeolite can improve mosquito production in smaller facilities. Zeolite could also offer cost-effective and environmentally friendly solutions for water recycling management systems in larger production facilities. Further studies are needed to optimise and assess the costs and benefits of such applications to Anopheles gambiae (s.l.) mosquito-rearing programmes. Graphic abstract


2013 ◽  
Vol 34 (2) ◽  
pp. 217-232 ◽  
Author(s):  
Selvino Neckel-Oliveira ◽  
Selvino Neckel-Oliveira ◽  
Ulisses Galatti ◽  
Selvino Neckel-Oliveira ◽  
Ulisses Galatti ◽  
...  

The objective of the present study is to identify the ecological characteristics of Amazonian frogs that would make them candidates for endangered species status, and to quantify correlations between body size and geographic distribution. The study included 180 species for which information was available on life history characteristics, including reproductive mode, aquatic larval development, primary larval habitat and adult microhabitat, and activity period. Species with aquatic development were classified in eight ecological groups based on a cluster analysis. Twenty-eight of the aquatic-developing species share a stream-based larval development stage with groups of endangered or vulnerable species from Australia and Central America. The Amazonian species have geographic ranges around five times larger than their Australian and Central American counterparts. The median clutch size and geographic range in aquatic-developing anuran species were 20 percent and 3.3 percent greater, respectively, than those of terrestrial-developing species. For both aquatic- and terrestrial-developing species, body size was positively associated with clutch size. Body size was also correlated with geographic range in aquatic-developing, but not in terrestrial species. Restricted geographic ranges and a lack of populations in protected areas were recorded in both groups. Most of these species occur in the southwestern Brazilian Amazon, which not only has poor coverage of protected areas, but is becoming increasingly threatened by ongoing economic development. The systematic monitoring of the region’s anurans and the creation of new conservation units should thus be of the highest priority.


Crustaceana ◽  
2021 ◽  
Vol 94 (1) ◽  
pp. 45-62
Author(s):  
Carolina Tropea ◽  
Liane Stumpf ◽  
Laura S. López Greco

Abstract The caridean shrimp Palaemon argentinus is a species of commercial and ecological interest. Its numerous larval stages, the lack of knowledge on their nutritional requirements, and their ability to survive in a wide range of salinities raise questions on the optimum conditions for larval rearing in captivity. The present study was aimed at evaluating embryonic development under different salinities and larval development under different combinations of salinities and diet regimes, in order to define alternative, cheaper culture conditions. We tested salinities usually encountered by the species in natural habitats (0.1, 1 and 5 ppt) and a highly protein-inert diet (Tetracolor®) as a potential replacement for live food (nauplii of Artemia salina). The incubation period and fecundity were similar among salinity treatments. Overall, the number of survival days and percentage of zoeae that moulted two, three and four times were higher when embryogenesis occurred at 5 ppt and when larvae were exposed to 5 ppt. These results suggest that the conditions experienced by embryos affect the performance of the first larval stages, and probably reflect the lower energetic requirements of zoeae to osmoregulate as water and haemolymph osmolarity become closer. On the other hand, larval performance was better when fed A. salina nauplii than Tetracolor®. The latter may not cover the nutritional requirements of zoeae or may have low digestibility due to insufficient enzymes in the undeveloped larval digestive system. Based on the present results, we conclude that a salinity of 5 ppt combined with a diet consisting of Artemia sp. nauplii is optimal for larval culture at early stages.


2018 ◽  
Vol 48 (4) ◽  
pp. 304-310 ◽  
Author(s):  
Thaís Billalba CARVALHO ◽  
Ellen Cristina Monteiro de SOUZA ◽  
Jaquelinne PINHEIRO-DA-SILVA ◽  
Marle Angélica VILLACORTA-CORREA

ABSTRACT Brycon amazonicus is a native Amazonian fish that is important for aquaculture in South America. Larval mortality is high in this species in intensive breeding systems due to aggressiveness among larvae. The present study investigated experimentally the effects of body size heterogeneity on the aggressive behavior and survival of B. amazonicus during the early stages of larval development. Two treatments (larvae groups with homogeneous and heterogeneous body size) were evaluated throughout early larval stages tested at six time points: 12, 24, 36, 48, 60 and 72 hours after hatching (HAH). Two experiments quantified, respectively, aggressive interactions and mortality rates among larvae at each time point. The frequency of aggressive interactions exhibited by the less aggressive larvae in each replicate was higher in the homogeneous size treatment. Aggressiveness was higher at 12 HAH, decreasing thereafter, and increasing again at 72 HAH. The mortality rate significantly increased with the larval stage, and was higher in the homogeneous than in the heterogeneous sized groups. Our results showed that aggressiveness in B. amazonicus larvae is affected by size variability and larval development stage. This knowledge about larval behavior is important to develop measures to improve larval health and survival in intensive production systems for this species.


Zootaxa ◽  
2012 ◽  
Vol 3241 (1) ◽  
pp. 1 ◽  
Author(s):  
WILLIAM T. WHITE

A taxonomic re-evaluation of the Carcharhinus sealei-dussumieri group using meristic and morphological data revealedthat this group consists of 5 species. Two species, Carcharhinus coatesi (Whitley, 1939) from northern Australia and prob-ably New Guinea and C. tjutjot (Bleeker, 1852) from Indonesian to Taiwan, are resurrected as valid species and togetherwith C. dussumieri and C. sealei are redescribed. Garrick’s lectotype designation of C. dussumieri and C. tjutjot areretained. A neotype for C. sealei, collected from the same locality as the holotype which was destroyed during World WarII, is designated. A fifth, possibly undescribed species (Carcharhinus sp.) is also noted from the Western Indian Oceanand its affinities briefly discussed. The four redescribed species are very similarly morphologically but can be distin-guished by a combination of meristic, morphological, dental and colour characters. The most important characters for dis-tinguishing these species are: vertebral counts, tooth counts, tooth morphology, shape of first dorsal and pectoral fins,second dorsal fin colouration, and mouth width. Two independent molecular studies have produced results which closely correlate with and support the findings of this study.


1973 ◽  
Vol 30 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Peter J. Colby ◽  
L. T. Brooke

Embryonic development of lake herring (Coregonus artedii) was observed in the laboratory at 13 constant temperatures from 0.0 to 12.1 C and in Pickerel Lake (Washtenaw County, Michigan) at natural temperature regimes. Rate of development during incubation was based on progression of the embryos through 20 identifiable stages.An equation was derived to predict development stage at constant temperatures, on the general assumption that development stage [Formula: see text] is a function of time (days, D) and temperature (T). The equation should also be useful in interpreting estimates from future regressions that include other environmental variables that affect egg development.A second regression model, derived primarily for fluctuating temperatures, related development rate for stage [Formula: see text], expressed as the reciprocal of time, to temperature (x). The generalized equation for a development stage is:[Formula: see text]In general, time required for embryos to reach each stage of development in Pickerel Lake agreed closely with the time predicted from this equation, derived from our laboratory observations. Hatching time was predicted within 1 day in 1969 and within 2 days in 1970.We used the equations derived with the second model to predict the effect of the super-imposition of temperature increases of 1 and 2 C on the measured temperatures in Pickerel Lake. Conceivably, hatching dates could be affected sufficiently to jeopardize the first feeding of lake herring through loss of harmony between hatching date and seasonal food availability.


2021 ◽  
Author(s):  
Nwamaka Oluchukwu Akpodiete ◽  
Frederic Tripet

Abstract BackgroundMalaria vector control approaches that rely on mosquito releases such as the sterile insect technique (SIT) and suppression or replacement strategies relying on genetically modified mosquitoes (GMM) depend on effective mass production of Anopheles mosquitoes. Anophelines typically require relatively clean larval rearing water, and water management techniques that minimise toxic ammonia are key to achieving optimal rearing conditions in small and large rearing facilities. Zeolites are extensively used in closed-system fish aquaculture to improve water quality and reduce water consumption, thanks to their selective adsorption of ammonia and toxic heavy metals. The many advantages of zeolites include low cost, abundance in many parts of the world and environmental friendliness. However, so far, their potential benefit for mosquito rearing has not been evaluated.MethodsThis study evaluated the independent effects of zeolite and daily water changes (to simulate a continuous flow system) on the rearing of An. coluzzii under two feed regimes (powder or slurry feed) and larval densities (200 and 400 larvae per tray). The duration of larval development, adult emergence success and phenotypic quality (body size) were recorded to assess the impact of water treatments on mosquito numbers, phenotypic quality and identification of optimal feeding regimes and larval density for the use of zeolite.ResultsOverall, mosquito emergence, duration of development and adult phenotypic quality was significantly better in treatments with daily water changes. In treatments without daily water changes, zeolite significantly improved water quality at the lower larval rearing density, resulting in higher mosquito emergence and shorter development time. At the lower larval rearing density, the adult phenotypic quality did not significantly differ between zeolite treatment without water changes and those with daily changes. ConclusionsThese results suggest that treating rearing water with zeolite can improve mosquito production in smaller facilities. Zeolite could also offer cost-effective and environmental-friendly solutions for water recycling management systems in larger production facilities. Further studies are needed to optimise and assess the costs and benefits of such applications to Anopheles gambiae s.l. mosquito rearing programmes.


Author(s):  
A. Jones

Methods are described for rearing turbot (Scophthalmus maximus L.) and brill (Scophthalmus rhombus L.) to late larval stages; the major part of the work was done on the former species. Turbot were reared to 16–0 mm and brill to 17–0 mm in length. Rearing tanks ranged in capacity from 8 to 60 1. Turbotlarvae hatched at 2–7–3–0 mm and successful first feeding was established on rotifers (Brachionus plicatilis) at a length of 3–6–3–8 mm; larvae were transferred to a diet of Artemia nauplii at 5–6—6–0 mm. Experiments on the effect of temperature on growth and yolkabsorption rates in yolksac turbot larvae showed optimal growth efficiency at 15–0 °C. Delayed initial feeding reduced subsequent survival. Drawings of larval development of turbot and brill were made as an aid to their identification in plankton samples.


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