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    • magazineArticle


      AP Surtida - SEAFDEC Asian Aquaculture, 2000 - Aquaculture Department, Southeast Asian Fisheries Development Center
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      Abalone culture 

      SMA Buen-Ursua - 2007 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Conceptualized by SM Buen-Ursua (Abalone Project).
    • Conference paper

      Abalone culture: an emerging aquaculture technology 

      AC Fermin - In Fishlink 2001, 29-31 May 2001, Sarabia Manor Hotel, Iloilo City, 2001 - University of the Philippines Aquaculture Society
    • Book

      Abalone hatchery 

      AC Fermin, MR de la Peña, RSJ Gapasin, MB Teruel, SMB Ursua, VC Encena II & NC Bayona - 2008 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 39
      This manual contains information on abalone hatchery operation, including site selection, design, culture of natural food, broodstock management, spawning, nursery, packing and transport, and profitability analyses.
    • Conference paper

      Community-based stock enhancement of abalone, Haliotis asinina in Sagay marine reserve: Achievements, limitations and directions 

      ND Salayo, RJG Castel, RT Barrido, DHM Tormon & T Azuma - In K Hajime, T Iwata, Y Theparoonrat, N Manajit & VT Sulit (Eds.), Consolidating the Strategies for Fishery Resources Enhancement in Southeast Asia. Proceedings of the Symposium … Strategy for Fisheries Resources Enhancement in the Southeast Asian Region, Pattaya, Thailand, 27-30 July 2015, 2016 - Training Department, Southeast Asian Fisheries Development Center
      The Sagay Marine Reserve (SMR) under the National Integrated Protected Area System (NIPAS) is one of the many reef areas in the Visayan Sea in the central part of the Philippine archipelago. The SMR covers 32,000 ha or 59% of coastal waters north of the mainland Sagay City. Donkey’s ear abalone is one of the most sought mollusks traded by small-scale fishers in Molocaboc Island located within the SMR. High buying prices in local and international markets compared with other fish catch motivated fishers to target abalone and caused its overfishing. SEAFDEC/AQD, with support from the Government of Japan Trust Fund (JTF), conducted a community-based stock enhancement through a tri-party collaboration between the fisherfolks of Molocaboc Island, the Sagay local government at the village and city levels, and SEAFDEC/AQD. The study showed that the decision and implementation of stock enhancement and the definition of its objectives and relevance involves the strong engagement with stakeholders. For over a period of eight years (2007-2014), we learned that stock enhancement necessarily involve high financial investments and enormous transaction cost over a long period of time which are often not affordable to local governments of coastal communities in Southeast Asia. Thus, community-based collaborations may help achieve enhancement and restocking goals.
    • Article

      Density dependent growth of the tropical abalone Haliotis asinina in cage culture 

      EC Capinpin Jr., JD Toledo, VC Encena II & M Doi - Aquaculture, 1999 - Elsevier
      The effects of different stocking densities on the growth, feed conversion ratio and survival of two size groups of the tropical abalone Haliotis asinina were determined. Three culture trials were conducted in net cages installed in a sheltered cove, Guimaras Province, Philippines. Trials 1 and 2 were conducted using 15–20 mm abalone juveniles for 150 days, while trial 3 was conducted using 35–40 mm abalone for 180 days. The animals were fed sufficient amounts of the red alga, Gracilariopsis bailinae (=G. heteroclada), throughout the experiment. There was an inverse relationship between growth (length and weight) and stocking density. Feed conversion ratio was not influenced by density, but was observed to be higher for larger animals. Survival was not significantly affected by density. Net cages are appropriate for culture of H. asinina. This study showed that H. asinina can reach commercial size of about 60 mm in one year. It also showed that growth of H. asinina can be sustained on a single-species diet. An economic analysis will be important in choosing the best stocking density for commercial production.
    • Article

      Diet development and evaluation for juvenile abalone, Haliotis asinina Linne: Lipid and essential fatty acid levels 

      MN Bautista-Teruel, SS Koshio & M Ishikawa - Aquaculture, 2011 - Elsevier
      Experiments on diet development and evaluation for juvenile abalone, Haliotis asinina focusing on lipid and essential fatty acid (EFA) levels were conducted. Six isonitrogenous diets were formulated in Experiment 1 (E1) to contain 27% protein with lipid levels at 0, 2, 4, 6, 8, and 10%. Experiment 2 (E2) (EFA levels), used the optimum lipid level (3.59%) in E1 with EFA supplementation of 0.0, 0.2, 0.4, 0.8, and 1.6%. Abalone juveniles [mean initial weight and shell length of 0.60 plus or minus 0.07g and 14.70 plus or minus 0.12mm (E1)], [0.60 plus or minus 0.16g and 15.30 plus or minus 0.73mm (E2)] respectively, were fed these diets at 2-5% body weight in 3 replicates. Feeding trials in 90days/experiment evaluated growth, survival, feed conversion ratio (FCR) and fatty acid composition in abalone tissues. Results showed significantly higher growth rates (ANOVA P<0.05) with abalone fed diets with lipid levels of 2.2%, 3.6%, and 6.1% compared with those containing lipid levels of 7.6% and 9.8%. Abalone fed the lipid-free diet showed significantly the lowest growth rate among treatments. Break point analysis as a function of growth, showed optimum lipid requirement at 3.59%. Survival was high at 95-99% in both experiments. FCR values for D3 and D4 were significantly better compared to D2, D5 and D6 (E1) while no significant differences were found for D2-D6 for E2. Abalone body lipid increased with corresponding increase in dietary lipid. Addition of 18:2n, 18:3n3, and n3 HUFA showed significant improvement in weight gains up to 1.6% supplementation. Fatty acid composition of the lipid samples reflected those of the diets. Total lipid of abalone fed the lipid-free diet showed higher monoenes. Addition of EFA resulted in an increase in both n3 and n6 fatty acids. Lipid incorporation at 3.6% using a 1:1 ratio of CLO and SBO with EFA supplementation (1.6%) is best in juvenile abalone diet formulation.
    • Article

      Diet development and evaluation for juvenile abalone, Haliotis asinina: animal and plant protein sources 

      MN Bautista-Teruel, AC Fermin & SS Koshio - Aquaculture, 2003 - Elsevier
      Growth studies were conducted to determine the suitability of animal and plant protein sources in the diet of abalone, Haliotis asinina. Juvenile abalone with mean initial weight and shell length of 0.69±0.04 g and 11.4±0.35 mm, respectively, were fed practical diets for 84 days at a temperature range of 28–31 °C. The practical diets contained 27% crude protein from various sources such as fish meal (FM), shrimp meal (SM), defatted soybean meal (DSM), and Spirulina sp. (SP). A formulated diet (diet 1) served as the control. The diets were fed to abalone at 2–5% body weight once daily at 1600 h. Weight gain (WG), increase in shell length (SL), specific growth rate (SGR), protein efficiency ratio (PER) and feed conversion ratio (FCR) were evaluated. Highest weight gain (WG: 454%) was attained with abalone fed diet 2 with protein sources coming from a combination of FM, SM, and DSM. This value was, however, not significantly different (P<0.05) from those fed diets 4 and 1 (Control diet) with protein sources coming from FM, SM, SP and FM, DSM, SM, respectively. Abalone fed diet 3, which used both plant protein sources, DSM and SP, showed significantly lower WG (327%). Survival was generally high ranging from 85% to 100% for all treatments. The SGR showed the same trend as the percent weight gain. The FCR and PER obtained, however, were not significantly different for all treatments. The amino acid profile of diets 1, 2, and 4 simulated that of the abalone protein, which could have been a contributing factor to the higher growth rate of abalone fed these diets. Diet 3, which contained only plant protein sources, showed relatively lower methionine values compared with the abalone muscle tissue. Although abalone are considered herbivorous animals, results of this study indicate that a combination of dietary plant and animal protein sources was necessary to attain the best growth rate.
    • Article

      Diet development and evaluation for juvenile abalone, Haliotis asinina: protein/energy levels 

      MN Bautista-Teruel & OM Millamena - Aquaculture, 1999 - Elsevier
      Juveniles of abalone, Haliotis asinina with mean initial weight and shell length of 0.6±0.03 g and 15±0.07 mm were fed practical diets for 90 days. The practical diets contained graded levels of protein from fish meal, shrimp meal, and soybean meal at 22 (diet 1), 27 (diet 2), and 32% (diet 3) with corresponding estimated metabolizable energy values of 3254, 3150, and 3090 kcal ME/kg diet. The amino acid profile and proximate analyses of muscle meat of the test animal and published nutrient requirements of other species of Haliotids were used as a basis for formulating and developing these practical diets. The diets were fed to abalone at 2–5% body weight once daily (1600 h) for biological evaluation in terms of weight gain (WG), increase in shell length (SL), specific growth rate (SGR), protein efficiency ratio (PER), feed conversion ratio (FCR) and for physical evaluation in terms of shell coloration of the animal. Natural food, Gracilariopsis bailinae (17% CP/2200 kcal ME/kg) (NF) fed ad libitum served as the control. Better growth rates, in terms of WG and SL, FCR and PER were noted in abalone fed the three formulated diets compared with those fed seaweed, G. bailinae. Abalone fed diets 3 (WG: 347%; SGR: 0.81; SL: 140%) and 2 (WG: 307%; SGR: 0.70; SL: 139%) showed significantly better growth rate than those fed diet 1 (WG: 252%; SGR: 0.51; SL: 132%). Natural food-fed abalone had the lowest WG (134%), SGR (0.06) and increase in SL (77%). Survival was generally high at 85–95% for all treatments. FCR (1.5–2.3) and PER (2.19–2.47) for animals fed the three diets were significantly better than for those fed natural food (0.10 PER and 6.98 FCR). Regression analysis showed the optimum protein level for juvenile abalone to be 27% with an energy level of 3150 kcal/kg ME. Abalone juveniles fed the formulated diets produced shells with light bluish green color while those fed seaweed retained the original brown color. Diet 2 which contained 27% protein, 5% lipid and 40% carbohydrates with an energy value of 3150 kcal/kg ME may be used as a basal diet for the rearing of juvenile abalone, H. asinina.
    • Conference paper

      The effect of stocking density, temperature and light on the early larval survival of the abalone Haliotis asinina Linné 

      JA Madrones-Ladja & BB Polohan - Phuket Marine Biological Center Special Publication, 2001 - Phuket Marine Biological Center
      Newly hatched trocophore larvae of the abalone haliotis asinina linne were stocked at densities of 1000, 3000 and 5000 larvae/1 at low (20-25oC) and high (ambien, 28-30oC) water temperature levels in light (transparent) and dark (black cloth-coered) lass container. Larvae were reared in UV light-irradiated sea water until pre-settement stage. Aeration was not provided during the 20-h incubation periond. A 3x2x2 factorial design with three replicates per treatment was folloed.

      A three-way analysis of variance (ANOVA) showed a significant interaction among the factors tested. Analysis at each density level showed that at stocking density of 1000 larvae/1, no significant difference between temperatures and between light or dark condition was observed. However, at densities of 3000 and5000, significantly higher survival was obtained at low, than high temperature (P<0.05), but no difference between the light and darck conditions. Analysis at each temperature showed that, at high temperature,better survival was obtained at stocking density of 1000, than higher densities (P<0.001), and at light than at darck condition (P<0.05). However, at low temperature, no significant difference between light abd darck conditions was detected. ANOVA at light or darck condition showed that at any of these conditons, larvae survival was always higher at 1000 stocking density that t other density

      (P 0.05). Survival was not significntly different between stockng density of 3000 and 5000 larvae/1 at any of those light conditions. Theredore, during incubation of newly hatched trocophore larvae of H. Asinina to pre-settlement stage, the optimum stocking density at high temperature (28-30oC) was 1000/1, in a light-penetrable rearing container. When reared at higherstocking densities of 3000 or 5000, a higher survival was obtained when temperature was lower to 20-25oC in either rearing conditions tested.
    • Article

      Effects of alternate starvation and refeeding cycles on food consumption and compensatory growth of abalone, Haliotis asinina (Linnaeus). 

      AC Fermin - Aquaculture Research, 2002 - Blackwell Publishing
      The effects of alternate starvation and refeeding on food consumption and compensatory growth of hatchery-bred abalone, Haliotis asinina (Linnaeus), were determined. Two groups of abalone juveniles (mean shell length = 29 mm, body weight = 5 g) were alternately starved and refed a macro-alga, Gracilariopsis bailinae at equal duration (5/5 or 10/10) over 140 days. A control group (FR) was fed the seaweed ad libitum throughout a 200-day experimental period. Starved and refed abalone showed slower growth rates (DGR, 63 and 70 mg/day in the 5/5 and 10/10 groups respectively), as a result of reduced food intake (DFI 15% and 16% day−1 respectively), after repeated starvation and refeeding cycles. Percentage weight gains (5/5 = 196%, 10/10 = 177%) were significantly lower than that of the control (397%). When refed continuously over 60 days, the starved groups exhibited increased DFI and fed at the rate of 24% and 25% day−1, which were not significantly different from that of the control at 26% day−1. At the end of the experiment, no significant differences were observed among three treatments in terms of shell length (range: 46–48 mm), body weight (range 25–28 g), % weight gain (392–465%) and per cent survival (range 87–98%). The results indicated that H. asinina had a complete compensatory growth following a return to full rations after a series of intermittent starvation and refeeding cycles.
    • Article

      Effects of elevated temperature on the different life stages of tropical mollusk, donkey's ear abalone (Haliotis asinina) 

      FL Pedroso - Aquaculture, Aquarium, Conservation and Legislation, 2017 - Bioflux
      The increase in sea surface temperature associated with climate change can cause tremendous impact on the different life stages of aquatic organisms, particularly on the tropical species. The present study investigates the effect of elevated temperature on hatching rate, growth and survival of larvae and breeders of tropical mollusk, donkey’s ear abalone (Haliotis asinina). Different life stages of abalone were exposed to the following temperature treatments: ambient (29°C), +2°C (31°C), and +4°C (33°C). Hatching rate was significantly reduced when the fertilized eggs were incubated at temperature 4°C above ambient. Increase in temperature at 2°C above ambient can significantly influence the survival of larvae. Significant decline in the survival was observed when the larvae were exposed at temperatures 31°C and 33°C, however bigger larvae were observed in groups reared at 31°C, while those larvae that were reared in 33°C were significantly smaller. Furthermore, reduced growth, feeding rate and survival were also observed in breeders reared at elevated temperature. The result of the study suggests that early developmental stages and reproducing adult abalone were vulnerable to the impact of climate change.
    • Article

      Enriched Ulva pertusa as partial replacement of the combined fish and soybean meals in juvenile abalone Haliotis asinina (Linnaeus) diet 

      R Santizo-Taan, M Bautista-Teruel & JRH Maquirang - Journal of Applied Phycology, 2019 - Springer Verlag
      The potential of enriched Ulva pertusa meal as feed ingredient in abalone juveniles, Haliotis asinina was evaluated. Four isonitrogenous and isolipidic diets were formulated which contain 27% protein and 5% lipid. Enriched U. pertusa meal replaced 0% (control), 10%, 20%, and 30% of protein from fish and soybean meals in the formulated diets. Thirty randomly selected abalone juveniles with average weight and shell length of 0.45 g ± 0.01 and 12.71 mm ± 0.01, respectively, were placed in each of the twelve 60-L oval fiberglass tanks equipped with a flow-through seawater system. Abalone were given diets at 3–5% body weight daily for 120 days in three replicate samples. Results showed no significant differences (p > 0.05) in percent weight gain, shell length, specific growth rate, feed conversion ratio, and protein efficiency ratio even up to 30% replacement level. Apparent dry matter digestibility of U. pertusa meal in abalone diet was 92%. Crude protein content of the abalone fed diets 1 (10% enriched U. pertusa meal) and 3 (30% enriched U. pertusa meal) was significantly (p < 0.05) higher than those fed on basal diet. Enriched U. pertusa meal can partially replace fish and soybean meals as protein source in formulated diets for abalone, Haliotis asinina juveniles.
    • Article

      Evaluation of density and cage design for the nursery and grow-out of the tropical abalone Haliotis asinina Linne 1758 

      VC Encena II, M de la Peña & VT Balinas - Journal of Shellfish Research, 2013 - National Shellfisheries Association
      The effect of stocking density and cage design on the growth, survival rate, and feed conversion ratio was evaluated for the nursery (11–15 mm in shell length) and juvenile grow-out (26–30 mm in shell length) of the tropical abalone Haliotis asinina. Abalone were fed Gracilaria sp. within a randomized 2 × 3 factorial experiment using 2 stocking densities (Tl (500 pieces/m2) and T2 (1,000 pieces/m2)) and 3 cages (D1, box; D2, mesh cage; D3, prefabricated multitier trays). In addition, 3 stocking densities (T1, 50 pieces/m ; T2, 100 pieces/m; T3, 200 pieces/m) were evaluated in the prefabricated multitier trays. We found that, in the nursery experiment, 4-mo-old tropical abalone juveniles reared for 90 d showed no significant differences in growth (shell length and body weight) and survival rates among the 3 nursery cages used (Tukey's post hoc test, P > 0.05). Feed conversion ratio, however, was lowest for the high-density treatment T1D3 (7.8 ± 0.76) and was significantly different from the low density treatment T1D1 (11.32 ± 1.2) and intermediate density treatment T1D2 (12.39 ± 1.12; t-test, P > 0.05). Conversely, at higher densities (T2), the same trend applied with abalone reared in multitier basket systems (T2D3), having the highest growth rates and survival rates (29.3 ± 0.07 mm average shell length (ASL) and 5.16 ± 0.52 g average body weight (ABW)), followed closely by those reared in mesh cages (T2D2) and boxes (T2D1). Feed conversion ratio was also lowest for T2D3 (7.56 ± 0.79) and was significantly lower than T2D1 and T2D2. Between treatments, however, abalone reared at lower densities (T1) had significantly higher growth and survival than those reared at higher densities (T2), regardless of the nursery cage used, indicating an inverse relationship between stocking density, growth, and survival. For the grow-out study, tropical abalone reared in multitier trays at low densities (T1) attained the highest growth in shell length and body weight (49.7 ± 0.11 mm ASL and 29.8 ± 2.6 g ABW, respectively) at 180 d of culture, which was significantly greater than those reared in the high-density treatment (T3) with significantly smaller shell length and body weight (43.8 ± 0.18 mm ASL and 21.2 ± 2.0 g ABW), but not significantly different than the intermediate density treatment. This trend started from day 60 of culture onward when analyzed using Duncan's multiple range test (P > 0.05). Survival rates were not significantly different among stocking density treatments, nor were feed conversion ratios. We recommend, for nursery rearing of abalone juveniles, using multitier trays (D3) or boxes (D1) at 500 pieces/m2 stocking density to attain a grow-out size of 26–30 mm in shell length in 90 days. A stocking density of 100 pieces/m2 is recommended to grow abalone in multitier trays to attain a cocktail size of 50 mm ASL and 30 g ABW in 180 d with survival rates between 85.6% and 83.1%.
    • Article

      Evaluation of mucus, Navicula, and mixed diatoms as larval settlement inducers for the tropical abalone Haliotis asinina 

      WG Gallardo & SMA Buen - Aquaculture, 2003 - Elsevier
      Different biological films reportedly effective in larval settlement of other abalone species were tested on the tropical abalone Haliotis asinina to determine the most effective settlement inducers for the species. Larval attachment was significantly higher on mucus, Navicula, Navicula+mucus, and mixed diatoms+mucus than on mixed diatoms and the blank control. Metamorphosis was significantly higher on Navicula, Navicula+mucus. These results indicate the important contribution of mucus in larval settlement and the effectiveness of Navicula as a single species over mixed diatoms in larval settlement of the tropical abalone H. asinina.
    • Book

      Farming of the tropical abalone Haliotis asinina 

      VC Encena II & NC Bayona - 2010 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 49
      This manual was written to provide abalone growers a practical guide on how to culture abalone based on the studies and trials conducted by SEAFDEC Aquaculture Department.
    • Article

      Feeding, growth and survival of abalone (Haliotis asinina Linnaeus 1758) reared at different stocking densities in suspended mesh cages in flow-through tanks 

      AC Fermin & SM Buen - The Philippine Scientist, 2000 - San Carlos Publications, University of San Carlos
      Feeding, growth and survival of hatchery-bred juvenile abalone, Haliotis asinina (mean initial shell lengths: 32 mm) stocked at 25, 50 and 100 m-2 of shelter surface area in mesh cages suspended in indoor tanks were determined. Animals were fed the seaweed, Gracilariopsis bailinae, to excess given at weekly intervals. After 250 d, avereage daily growth rate (mean: 122 µm d-1 shell length, 156 mg d-1 body weight) was highest in abalone reared at the lowest stocking density (25 m-2 ). Abalone stocked at 50 and 100 m-2 had similar growth rates that ranged from 96 to 98 µm d-1 SL and 123 to 131 mg d-1 BW). Daily feeding rates of 29 and 30% were not significantly different for abalone stocked at 25 and 50 m-2, respectively, but were higher than abalone stocked at 100 m-2. The higher feeding rates of 24-28% day-1 of abalone in all treatments starting day-129 until day-160 could be due to the onset of sexual maturation as most abalone are already mature at this size. Survival rates were generally high (91-98%) and were not significantly different among treatments. However, body size (range: 59.3 mm SL, 57-58.4 g BW) at harvest was bigger in animal stocked at 25 m-2 than those stocked at 100 m-2. Sexual maturation during culture did not hamper growth of abalone. G. bailinae proved to be a sufficient food source for abalone grow-out. A stocking density between 50-100 m-2 is recommended for tank grow-out of H. asinina.
    • Article

      Grow-out culture of tropical abalone, Haliotis asinina (Linnaeus) in suspended mesh cages with different shelter surface areas 

      AC Fermin & SM Buen - Aquaculture International, 2002 - Kluwer Academic Publishers
      This study investigated the effects of shelter surface area (SSA) on the feeding, growth and survival of the donkey-ear abalone, Haliotis asinina reared in mesh cages (0.38×0.38×0.28m) suspended in flow-through tanks (water volume = 6 m3). Cages had sections of polyvinylchloride (PVC) that provided shelters with surface area of 0.22 m2, 0.44 m2 and 0.66 m2. Hatchery-produced abalone with initial shell length of 32 ± 1 mm and wet weight of 7.5 g were stocked at 50 individuals cage−1 that corresponded to stocking densities of ca. 227, 113 and 75 abalone m−2 of SSA. The ratios of shelter surface area to cage volume (SSA:CV) were 5.5, 11 and 16.5. Abalones were provided an excess red seaweed Gracilariopsis bailinae (= Gracilaria heteroclada) at weekly intervals over a 270-day culture period. Feeding rates (18–20% of wet weight), food conversion ratio (26–27) and percent survival (88–92%) did not differ significantly among treatments (p > 0.05). Body size at harvest ranged from 56 to 59 mm SL and 52 to 57 g wet body weight with significant differences between abalone reared at SSA 0.22 m2 and 0.66 m2 (p < 0.05). Abalone reared in cages with 0.66 m2 SSA grew significantly faster at average daily growth rates of 132 μm and 188 mg day−1. Stocking densities of 75–113m−2 SSA in mesh cages suspended in flow-through tanks resulted in better growth of abalone fed red seaweed.
    • Article

      Growth rate of the Philippine abalone, Haliotis asinina fed an artificial diet and macroalgae 

      EC Capinpin Jr. & KG Corre - Aquaculture, 1996 - Elsevier
      The growth rate of Haliotis asinina fed three diets was evaluated over a 120 day period. Juveniles fed the red alga Gracilariopsis heteroclada and an artificial diet grew faster in terms of both total body weight and shell length than those fed the red alga Kappaphycus alvarezii. Juveniles fed the artificial diet produced more weight than those fed G. heteroclada for the first 90 days, but abalone fed G. heteroclada grew faster from Day 105 onwards. In terms of shell length, the artificial diet produced faster growth rates than G. heteroclada for the first 75 days but from Day 90 onwards, faster growth rates were observed in juveniles fed G. heteroclada. Reductions in daily growth rates of juveniles during the latter phase of the growth trial were attributed to channelling of energy into gonad development. G. heteroclada promoted high growth rates over a long-term period (360 days) and is considered to be best suited for abalone farming in the Philippines.
    • Article

      Induction of larval settlement and metamorphosis in the donkey-ear abalone, Haliotis asinina Linnaeus, by chemical cues 

      RSJ Gapasin & BB Polohan - Hydrobiologia, 2004 - Springer Verlag
      The effects of the chemical inducers, gamma-aminobutyric acid (GABA) and potassium chloride (KCl), on the larval settlement and metamorphosis of the donkey-ear abalone, Haliotis asinina, was investigated. H. asinina larvae (5–6 h post-hatch) were exposed to a range of GABA (0.125–2.00 μM) and KCl (1.00–12.00 mM) concentrations for 72 h. Results of the dose response experiments showed that settlement and metamorphosis vary according to the dose levels of the inducer compounds. Under controlled laboratory conditions, 0.45–0.50 μM and 6.0 mM seemed to be the optima for GABA and KCl, respectively, as these concentrations elicited the greatest number of postlarvae that metamorphosed, settled or survived. However, GABA generally promoted better attachment and metamorphic response as well as survival than KCl in H. asinina postlarvae.