<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>UTas ePrints - Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture</title> <script type="text/javascript" src="http://eprints.utas.edu.au/javascript/auto.js"><!-- padder --></script> <style type="text/css" media="screen">@import url(http://eprints.utas.edu.au/style/auto.css);</style> <style type="text/css" media="print">@import url(http://eprints.utas.edu.au/style/print.css);</style> <link rel="icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="Top" href="http://eprints.utas.edu.au/" /> <link rel="Search" href="http://eprints.utas.edu.au/cgi/search" /> <meta content="Cobcroft, J.M." name="eprints.creators_name" /> <meta content="jenny.cobcroft@utas.edu.au" name="eprints.creators_id" /> <meta content="thesis" name="eprints.type" /> <meta content="2007-02-01" name="eprints.datestamp" /> <meta content="2008-01-08 15:30:00" name="eprints.lastmod" /> <meta content="show" name="eprints.metadata_visibility" /> <meta content="Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture" name="eprints.title" /> <meta content="unpub" name="eprints.ispublished" /> <meta content="270503" name="eprints.subjects" /> <meta content="300703" name="eprints.subjects" /> <meta content="public" name="eprints.full_text_status" /> <meta content="marine fish larvae, vision, sensory organs, feeding behaviour, striped trumpeter, light intensity, greenwater, turbidity, rotifers, larval fish culture, aquaculture, jaw development, jaw malformation" name="eprints.keywords" /> <meta content="Striped trumpeter (Latris lineata) is a new candidate species for aquaculture in temperate Australia. Survival of larvae prior to flexion has proven a bottleneck in the production of this species for culture. In addition, almost all juveniles cultured to date exhibit malformations of the jaw that may impede larval feeding success. Body size and morphology impose constraints upon feeding success in larvae of broadcast spawning fishes. Furthermore, larvae have an absolute reliance upon sense organs for the detection and subsequent capture of prey. In this study, aspects of morphological development and feeding performance were described in larval striped trumpeter. Chemosensory and mechanosensory organs were present and presumed functional soon after hatching, while the eye was functional coincident with first-feeding on day 7 post-hatching. The structure of the photoreceptors in different regions of the retina of the larvae suggested the area specialised for the most acute image formation corresponded to a visual field in the fronto-ventral region. Analysis of videocinematography of feeding larvae in the horizontal plane confirmed a forward-directed functional visual field. The area of the visual field increased with larval ontogeny from day 13 to day 17 post-hatching, due to the wider range of reactive angles used by older larvae. Maximum reactive distances of larvae to rotifer prey (~5.1mm) were 97% of larval standard length, while the distance at which larvae initiated a strike at the prey was much lower (~0.45mm) at 8% of larval standard length. Visual angles determined from larval feeding behaviour were higher than the minimum separable angles predicted by histology, such that the functional acuity of the larvae was not as good as that predicted by retinal structure. Jaw malformation was only evident in post-flexion larvae greater than 10 mm standard length and was characterised by an open jaw in which cartilage and bone elements appeared structurally normal but were in abnormal positions. The effects of light intensity and microalgal cell density (turbidity) on larval feeding behaviour were assessed in short-term feeding trials. None of the pre-flexion larvae used to investigate optimal light conditions for feeding exhibited jaw malformations. Larvae fed equally well in clearwater (no microalgal cells present) in a light intensity range of 1-10 umol.s-1.m-2. An ontogenetic improvement in photopic visual sensitivity of larvae was indicated by improved feeding at 0.1 umol.s-1.m-2 between day 8 and day 23 post-hatching. Algae-induced turbidity had different effects on larval feeding response dependent upon the previous visual environment of the larvae. Young larvae, day 9 post-hatching, reared in clearwater showed decreased feeding capabilities with increasing turbidity, while older clearwater reared larvae fed well at all turbidities tested. Likewise, greenwater (with microalgal cells present) reared larvae had increased feeding capabilities in the highest algal cell densities tested compared with those in low algal cell density, and clearwater to which they were naive. This study demonstrated that striped trumpeter larvae are primarily visual feeders with a small visual field relative to larval body size, that jaw malformation is unlikely to impede feeding in pre-flexion larvae, and that greenwater may provide a benefit to larval feeding although the previous visual environment of larvae affected subsequent feeding responses." name="eprints.abstract" /> <meta content="2002-01" name="eprints.date" /> <meta content="published" name="eprints.date_type" /> <meta content="213" name="eprints.pages" /> <meta content="University of Tasmania" name="eprints.institution" /> <meta content="School of Aquaculture" name="eprints.department" /> <meta content="phd" name="eprints.thesis_type" /> <meta content="Barahona-Fernandes, M. H., 1979. Some effects of light intensity and photoperiod on the sea bass larvae (Dicentrarchus labrax (L.)) reared at the Centre Oceanologique de Bretagne. Aquaculture 17, 311-321. Battaglene, S. C. and Talbot, R. B., 1990. Initial swim bladder inflation in intensively reared Australian bass larvae, Macquaria novemaculeata (Steindachner) (Perciformes: Percichthyidae). Aquaculture 86, 431-442. Battaglene, S. C., McBride, S. and Talbot, R. B., 1994. Swim bladder inflation in larvae of cultured sand whiting, Sillago ciliata Cuvier (Sillaginidae). Aquaculture 128, 177-192. Batty, R. S. and Hoyt, R. D., 1995. The role of sense organs in the feeding behaviour of juvenile sole and plaice. J. Fish Biol. 47, 931-939. Bell, M. V., Batty, R. S., Dick, J. R., Fretwell, K., Navarro, J. C. and Sargent, J. R., 1995. Dietary deficiency of docosahexanoic acid impairs vision at low light intensities in juvenile herring (Clupea harengus L.). Lipids 30(5), 443-449. Blaxter, J. H. S., 1986. Development of sense organs and behaviour of teleost larvae with special reference to feeding and predator avoidance. Trans. Amer. Fish. Soc. 115(1), 98-114. Blaxter, J. H. S., 1988. Pattern and variety in development. In: W. S. Hoar and D. J. Randall (Eds.), Fish Physiology - Volume X1A. Academic Press, London, pp. 1-58. Blaxter, J. H. S. and Fuiman, L. A., 1989. Function of the free neuromasts of marine teleost larvae. In: S. Coombs, P. Gorner and H. Munz (Eds.), The Mechanosensory Lateral Line. Neurobiology and Evolution. Springer-Verlag, New York, pp. 481-499. Boehlert, G. W. and Morgan, J. B., 1985. Turbidity enhances feeding abilities of larval Pacific herring, Clupea harengus pallasi. Hydrobiologia 123, 161-170. Boeuf, G. and Le Bail, P.-Y., 1999. Does light have an influence on fish growth? Aquaculture 177, 129-152. Boglione, C., Cataldi, E., de Francesco, M., Giganti, M., Gratani, M., Selmo, C. and Cataudella, S., 2001a. Morphoecology and feeding behaviour in larval finfish: a new candidate species for aquaculture. In: C. I. Hendry, G. Van Stappen, M. Wille and P. Sorgeloos (Eds.), Larvi '01 - Fish and shellfish larviculture symposium, Gent, Belgium. European Aquaculture Society, Special Publication No.30, 72-75. Boglione, C., Gagliardi, F., Scardi, M. and Cataudella, S., 2001b. Skeletal descriptors and quality assessment in larvae and post-larvae of wild-caught and hatchery-reared gilthead sea bream (Sparus aurata L. 1758). Aquaculture 192, 1-22. Breck, J. E. and Gitter, M. J., 1983. Effect of fish size on the reactive distance of bluegill (Lepomis macrochirus) sunfish. Can. J. Fish. Aquat. Sci. 40, 162-167. Bristow, B. T., Summerfelt, R. C. and Clayton, R. D., 1996. Comparative performance of intensively cultured larval walleye in clear, turbid, and coloured water. Prog. Fish-Cult. 58(1), 1-10. Bromage, N., 1995. Broodstock management and seed quality - general considerations. In: N. R. Bromage and R. J. Roberts (Eds.), Broodstock management and egg and larval quality. Blackwell Science Ltd, Oxford, pp. 1-24. Browman, H. I. and O'Brien, W. J., 1992. Foraging and prey search behaviour of golden shiner (Notemigonus crysoleucas) larvae. Can. J. Fish. Aquat. Sci. 49, 813-819. Browman, H. I., Gordon, W. C., Evans, B. I. and O'Brien, W. J., 1990. Correlation between histological and behavioural measures of visual acuity in a zooplanktivorous fish, the white crappie (Pomoxis annularis). Brain, Behav. Evol. 35, 85-97. Butler, P. I., 1995. Visual ontogeny and feeding responses in cultured striped trumpeter, Latris lineata, larvae. Unpublished Hons thesis, Department of Aquaculture, University of Tasmania. Confer, J. L., Howick, G. L., Corzette, M. H., Framer, S. L., Fitzgibbon, S. and Landesberg, R., 1978. Visual predation by planktivores. Oikos 31, 27-37. Dempsey, C. H., 1978. Chemical stimuli as a factor in feeding and intraspecific behaviour of herring larvae. J. Mar. Biol. Ass. U.K. 58, 739-747. Douglas, R. H. and Hawryshyn, C. W., 1990. Behavioural studies of fish vision: an analysis of visual capabilities. In: R. H. Douglas and M. B. A. Djamgoz (Eds.), The Visual System of Fish. Chapman and Hall, London, pp. 373-418. Doving, K. B. and Knutsen, J. A., 1993. Chemokinesis in marine fish larvae. In: B. T. Walther and H. J. Fyhn (Eds.), Physiological and biochemical aspects in fish development. University of Bergen, Bergen, pp. 139-145. Dowd, C. E. and Houde, E. D., 1980. Combined effects of prey concentration and photoperiod on survival and growth of larval sea bream, Archosargus rhomboidalis (Sparidae). Mar. Ecol. Prog. Ser. 3, 181-185. Duray, M. and Kohno, H., 1988. Effects of continuous lighting on growth and survival of first-feeding larval rabbitfish, Siganus guttatus. Aquaculture 72, 73-79. Evans, B. I. and O'Brien, W. J., 1988. A reevaluation of the search cycle of planktivorous arctic grayling, Thymallus arcticus. Can. J. Fish. Aquat. Sci. 45, 187-192. Gapasin, R. S. J., Bombeo, R., Lavens, P., Sorgeloos, P. and Nelis, H., 1998. Enrichment of live food with essential fatty acids and vitamin C: effects on milkfish (Chanos chanos) larval performance. Aquaculture 162, 269-286. Gulbrandsen, J., 1996. Effects of spatial distribution of light on prey ingestion of Atlantic halibut larvae. J. Fish Biol. 48, 478-483. Hunter, J. R., 1980. The feeding behaviour and ecology of marine fish larvae. In: J. E. Bardach, J. J. Magnuson, R. C. May and J. M. Reinhart (Eds.), Fish behaviour and its use in the capture and culture of fishes. International Center for Living Aquatic Resources Management, Manila, Philippines, pp. 287-330. Iwai, T., 1980. Sensory anatomy and feeding of fish larvae. In: J. E. Bardach, J. J. Magnuson, R. C. May and J. M. Reinhart (Eds.), Fish behaviour and its use in the capture and culture of fishes. International Center for Living Aquatic Resources Management, Manila, Philippines, pp. 124-145. Kanazawa, A., Teshima, S., Inamori, S., Iwashita, T. and Nagao, A., 1981. Effects of phospholipids on growth, survival rate, and incidence of malformation in the larval ayu. Mem. Fac. Fish., Kagoshima Univ. 30, 301-309. Kawamura, G., Mori, H. and Kuwahara, A., 1989. Comparison of sense organ development in wild and reared flounder Paralichthys olivaceus larvae. Nippon Suisan Gakkaishi 55(12), 2079-2083. Knutsen, J. A., 1992. Feeding behaviour of North sea turbot (Scophthalmus maximus) and Dover sole (Solea solea) larvae elicited by chemical stimuli. Mar. Biol. 113, 543-548. Lazo, J. P., Dinis, M. T., Holt, G. J., Faulk, C. and Arnold, C. R., 2000. Co-feeding microparticulate diets with algae: toward eliminating the need of zooplankton at first feeding in larval red drum (Sciaenops ocellatus). Aquaculture 188, 339-351. Luecke, C. and O'Brien, W. J., 1981. Prey location volume of a planktivorous fish: a new measure of prey vulnerability. Can. J. Fish. Aquat. Sci. 38, 1264-1270. Miner, J. G. and Stein, R. A., 1993. Interactive influence of turbidity and light on larval bluegill (Lepomis macrochirus) foraging. Can. J. Fish. Aquat. Sci. 50, 781-788. Naas, K. E., Naess, T. and Harboe, T., 1992. Enhanced first feeding of halibut larvae (Hippoglossus hippoglossus L.) in green water. Aquaculture 105, 143-156. Neave, D. A., 1984. The development of visual acuity in larval plaice (Pleuronectes platessa L.) and turbot (Scophthalmus maximus L.). J. Exp. Mar. Biol. Ecol. 78, 167-175. Ostrowski, A. C., 1989. Effect of rearing tank background color on early survival of dolphin larvae. Prog. Fish-Cult. 51, 161-163. Pankhurst, P. M., 1994. Age-related changes in the visual acuity of larvae of New Zealand snapper, Pagrus auratus. J. Mar. Biol. Assoc. UK 74, 337-349. Pankhurst, P. M. and Hilder, P. E., 1998. Effect of light intensity on feeding of striped trumpeter Latris lineata larvae. Mar. Freshwater Res. 49, 363-368. Pittman, K., Solbakken, J. and Hamre, K., 2001. Control of metamorphosis in flatfish. In: C. I. Hendry, G. Van Stappen, M. Wille and P. Sorgeloos (Eds.), Larvi '01 - Fish and shellfish larviculture symposium, Gent, Belgium. European Aquaculture Society, Special Publication No.30, 476-477. Poling, K. R. and Fuiman, L. A., 1997. Sensory development and concurrent behavioural changes in Atlantic croaker larvae. J. Fish Biol. 51, 402-421. Poling, K. R. and Fuiman, L. A., 1998. Sensory development and its relation to habitat change in three species of Sciaenids. Brain, Behav. Evol. 52, 270-284. Reitan, K. I., Rainuzzo, J. R., Oie, G. and Olsen, Y., 1997. A review of the nutritional effects of algae in marine fish larvae. Aquaculture 155, 207-221. Ronzani Cerqueira, V. and Chatain, B., 1991. Photoperiodic effects on the growth and feeding rhythm of European seabass, Dicentrarchus labrax, larvae in intensive rearing. In: P. Lavens, P. Sorgeloos, E. Jaspers and F. Ollevier (Eds.), Larvi '91 - Fish and Crustacean Larviculture Symposium, Gent, Belgium. European Aquaculture Society, Special Publication No.15, 304-306. Takeuchi, T., Dedi, J., Haga, Y., Seikai, T. and Watanabe, T., 1998. Effect of vitamin A compounds on bone deformity in larval Japanese flounder (Paralichthys olivaceus). Aquaculture 169, 155-165. Tandler, A. and Helps, S., 1985. The effects of photoperiod and water exchange rate on growth and survival of gilthead sea bream (Sparus aurata, Linnaeus: Sparidae) from hatching to metamorphosis in mass rearing systems. Aquaculture 48, 71-82. Thomas, P., Arnold, C. R. and Holt, G. J., 1995. Red drum and other sciaenids. In: N. R. Bromage and R. J. Roberts (Eds.), Broodstock management and egg and larval quality. Blackwell Science Ltd, Oxford, pp. 118-137. Utne, A. C. W., 1997. The effect of turbidity and illumination on the reaction distance and search time of the marine planktivore Gobiusculus flavescens. J. Fish Biol. 50, 926-938. Utne-Palm, A. C., 1999. The effect of prey mobility, prey contrast, turbidity and spectral composition on the reaction distance of Gobiusculus flavescens to its planktonic prey. J. Fish Biol. 54, 1244-1258. van der Meer, H. J. and Anker, G. C., 1984. Retinal resolving power and sensitivity of the photopic system in seven Haplochromine species (Teleostei, Cichlidae). Neth. J. Zool. 34, 197-207. van der Meeren, T. and Naas, K. E., 1997. Development of rearing techniques using large enclosed ecosystems in the mass production of marine fish fry. Rev. Fish. Sci. 5(4), 367-390. Vinyard, G. L. and O'Brien, W. J., 1976. Effects of light and turbidity on the reactive distance of bluegill (Lepomis macrochirus). J. Fish. Res. Board Can. 33, 2845-2849. Wanzenbock, J. and Schiemer, F., 1989. Prey detection in cyprinids during early development. Can. J. Fish. Aquat. Sci. 46, 995-1001. Wanzenbock, J., Zaunreiter, M., Wahl, C. M. and Noakes, D. L. G., 1996. Comparison of behavioural and morphological measures of visual acuity of roach (Rutilus rutilus) and yellow perch (Perca flavescens). Can. J. Fish. Aquat. Sci. 53, 1506-1512. Wright, D. I. and O'Brien, W. J., 1982. Differential location of Chaoborous larvae and Daphnia by fish: the importance of motion and visible size. Am. Midl. Natural. 108(1), 68-73. Zohar, Y., Harel, M., Hassin, S. and Tandler, A., 1995. Gilt-head sea bream (Sparus aurata). In: N. R. Bromage and R. J. Roberts (Eds.), Broodstock management and egg and larval quality. Blackwell Science Ltd, Oxford, pp. 94-117." name="eprints.referencetext" /> <meta content="Cobcroft, J.M. (2002) Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture. PhD thesis, University of Tasmania." name="eprints.citation" /> <meta content="http://eprints.utas.edu.au/639/3/Front_matter.pdf" name="eprints.document_url" /> <meta content="http://eprints.utas.edu.au/639/4/Cobcroft_JM_Thesis.pdf" name="eprints.document_url" /> <link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" /> <meta content="Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture" name="DC.title" /> <meta content="Cobcroft, J.M." name="DC.creator" /> <meta content="270503 Animal Anatomy and Histology" name="DC.subject" /> <meta content="300703 Aquaculture" name="DC.subject" /> <meta content="Striped trumpeter (Latris lineata) is a new candidate species for aquaculture in temperate Australia. Survival of larvae prior to flexion has proven a bottleneck in the production of this species for culture. In addition, almost all juveniles cultured to date exhibit malformations of the jaw that may impede larval feeding success. Body size and morphology impose constraints upon feeding success in larvae of broadcast spawning fishes. Furthermore, larvae have an absolute reliance upon sense organs for the detection and subsequent capture of prey. In this study, aspects of morphological development and feeding performance were described in larval striped trumpeter. Chemosensory and mechanosensory organs were present and presumed functional soon after hatching, while the eye was functional coincident with first-feeding on day 7 post-hatching. The structure of the photoreceptors in different regions of the retina of the larvae suggested the area specialised for the most acute image formation corresponded to a visual field in the fronto-ventral region. Analysis of videocinematography of feeding larvae in the horizontal plane confirmed a forward-directed functional visual field. The area of the visual field increased with larval ontogeny from day 13 to day 17 post-hatching, due to the wider range of reactive angles used by older larvae. Maximum reactive distances of larvae to rotifer prey (~5.1mm) were 97% of larval standard length, while the distance at which larvae initiated a strike at the prey was much lower (~0.45mm) at 8% of larval standard length. Visual angles determined from larval feeding behaviour were higher than the minimum separable angles predicted by histology, such that the functional acuity of the larvae was not as good as that predicted by retinal structure. Jaw malformation was only evident in post-flexion larvae greater than 10 mm standard length and was characterised by an open jaw in which cartilage and bone elements appeared structurally normal but were in abnormal positions. The effects of light intensity and microalgal cell density (turbidity) on larval feeding behaviour were assessed in short-term feeding trials. None of the pre-flexion larvae used to investigate optimal light conditions for feeding exhibited jaw malformations. Larvae fed equally well in clearwater (no microalgal cells present) in a light intensity range of 1-10 umol.s-1.m-2. An ontogenetic improvement in photopic visual sensitivity of larvae was indicated by improved feeding at 0.1 umol.s-1.m-2 between day 8 and day 23 post-hatching. Algae-induced turbidity had different effects on larval feeding response dependent upon the previous visual environment of the larvae. Young larvae, day 9 post-hatching, reared in clearwater showed decreased feeding capabilities with increasing turbidity, while older clearwater reared larvae fed well at all turbidities tested. Likewise, greenwater (with microalgal cells present) reared larvae had increased feeding capabilities in the highest algal cell densities tested compared with those in low algal cell density, and clearwater to which they were naive. This study demonstrated that striped trumpeter larvae are primarily visual feeders with a small visual field relative to larval body size, that jaw malformation is unlikely to impede feeding in pre-flexion larvae, and that greenwater may provide a benefit to larval feeding although the previous visual environment of larvae affected subsequent feeding responses." name="DC.description" /> <meta content="2002-01" name="DC.date" /> <meta content="Thesis" name="DC.type" /> <meta content="NonPeerReviewed" name="DC.type" /> <meta content="application/pdf" name="DC.format" /> <meta content="http://eprints.utas.edu.au/639/3/Front_matter.pdf" name="DC.identifier" /> <meta content="application/pdf" name="DC.format" /> <meta content="http://eprints.utas.edu.au/639/4/Cobcroft_JM_Thesis.pdf" name="DC.identifier" /> <meta content="Cobcroft, J.M. (2002) Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture. 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border: solid 1px #ccc; padding: 3px"><tr> <td align="left"><a href="http://eprints.utas.edu.au/cgi/users/home">Login</a> | <a href="http://eprints.utas.edu.au/cgi/register">Create Account</a></td> <td align="right" style="white-space: nowrap"> <form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/search" style="display:inline"> <input class="ep_tm_searchbarbox" size="20" type="text" name="q" /> <input class="ep_tm_searchbarbutton" value="Search" type="submit" name="_action_search" /> <input type="hidden" name="_order" value="bytitle" /> <input type="hidden" name="basic_srchtype" value="ALL" /> <input type="hidden" name="_satisfyall" value="ALL" /> </form> </td> </tr></table></td></tr> <tr> <td class="toplinks"><!-- InstanceBeginEditable name="content" --> <div align="center"> <table width="720" class="ep_tm_main"><tr><td align="left"> <h1 class="ep_tm_pagetitle">Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture</h1> <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Cobcroft, J.M.</span> (2002) <xhtml:em>Aspects of the morphological development and feeding performance of larval striped trumpeter (Latris lineata) in culture.</xhtml:em> PhD thesis, University of Tasmania.</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_651' );" href="http://eprints.utas.edu.au/639/3/Front_matter.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_651' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_651"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/639/thumbnails/3/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/639/3/Front_matter.pdf"><span class="ep_document_citation">PDF (01: Front Matter)</span></a> - Requires a PDF viewer<br />83Kb</td></tr><tr><td valign="top" style="text-align:center"><a onmouseover="EPJS_ShowPreview( event, 'doc_preview_652' );" href="http://eprints.utas.edu.au/639/4/Cobcroft_JM_Thesis.pdf" onmouseout="EPJS_HidePreview( event, 'doc_preview_652' );"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a><div class="ep_preview" id="doc_preview_652"><table><tr><td><img alt="" src="http://eprints.utas.edu.au/639/thumbnails/4/preview.png" class="ep_preview_image" border="0" /><div class="ep_preview_title">Preview</div></td></tr></table></div></td><td valign="top"><a href="http://eprints.utas.edu.au/639/4/Cobcroft_JM_Thesis.pdf"><span class="ep_document_citation">PDF (02: Whole Thesis)</span></a> - Requires a PDF viewer<br />2789Kb</td></tr></table><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Striped trumpeter (Latris lineata) is a new candidate species for aquaculture in temperate Australia. Survival of larvae prior to flexion has proven a bottleneck in the production of this species for culture. In addition, almost all juveniles cultured to date exhibit malformations of the jaw that may impede larval feeding success. Body size and morphology impose constraints upon feeding success in larvae of broadcast spawning fishes. Furthermore, larvae have an absolute reliance upon sense organs for the detection and subsequent capture of prey. In this study, aspects of morphological development and feeding performance were described in larval striped trumpeter. Chemosensory and mechanosensory organs were present and presumed functional soon after hatching, while the eye was functional coincident with first-feeding on day 7 post-hatching. The structure of the photoreceptors in different regions of the retina of the larvae suggested the area specialised for the most acute image formation corresponded to a visual field in the fronto-ventral region. Analysis of videocinematography of feeding larvae in the horizontal plane confirmed a forward-directed functional visual field. The area of the visual field increased with larval ontogeny from day 13 to day 17 post-hatching, due to the wider range of reactive angles used by older larvae. Maximum reactive distances of larvae to rotifer prey (~5.1mm) were 97% of larval standard length, while the distance at which larvae initiated a strike at the prey was much lower (~0.45mm) at 8% of larval standard length. Visual angles determined from larval feeding behaviour were higher than the minimum separable angles predicted by histology, such that the functional acuity of the larvae was not as good as that predicted by retinal structure. Jaw malformation was only evident in post-flexion larvae greater than 10 mm standard length and was characterised by an open jaw in which cartilage and bone elements appeared structurally normal but were in abnormal positions. The effects of light intensity and microalgal cell density (turbidity) on larval feeding behaviour were assessed in short-term feeding trials. None of the pre-flexion larvae used to investigate optimal light conditions for feeding exhibited jaw malformations. Larvae fed equally well in clearwater (no microalgal cells present) in a light intensity range of 1-10 umol.s-1.m-2. An ontogenetic improvement in photopic visual sensitivity of larvae was indicated by improved feeding at 0.1 umol.s-1.m-2 between day 8 and day 23 post-hatching. Algae-induced turbidity had different effects on larval feeding response dependent upon the previous visual environment of the larvae. Young larvae, day 9 post-hatching, reared in clearwater showed decreased feeding capabilities with increasing turbidity, while older clearwater reared larvae fed well at all turbidities tested. Likewise, greenwater (with microalgal cells present) reared larvae had increased feeding capabilities in the highest algal cell densities tested compared with those in low algal cell density, and clearwater to which they were naive. This study demonstrated that striped trumpeter larvae are primarily visual feeders with a small visual field relative to larval body size, that jaw malformation is unlikely to impede feeding in pre-flexion larvae, and that greenwater may provide a benefit to larval feeding although the previous visual environment of larvae affected subsequent feeding responses.</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Thesis (PhD)</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">marine fish larvae, vision, sensory organs, feeding behaviour, striped trumpeter, light intensity, greenwater, turbidity, rotifers, larval fish culture, aquaculture, jaw development, jaw malformation</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270503.html">270000 Biological Sciences > 270500 Zoology > 270503 Animal Anatomy and Histology</a><br /><a href="http://eprints.utas.edu.au/view/subjects/300703.html">300000 Agricultural, Veterinary and Environmental Sciences > 300700 Fisheries Sciences > 300703 Aquaculture</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">639</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Dr Jennifer Cobcroft</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">01 Feb 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=639;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=639">item control page</a></p> </td></tr></table> </div> <!-- InstanceEndEditable --></td> </tr> <tr> <td><!-- #BeginLibraryItem "/Library/footer_eprints.lbi" --> <table width="795" border="0" align="left" cellpadding="0" class="footer"> <tr valign="top"> <td colspan="2"><div align="center"><a href="http://www.utas.edu.au">UTAS home</a> | <a href="http://www.utas.edu.au/library/">Library home</a> | <a href="/">ePrints home</a> | <a href="/contact.html">contact</a> | <a href="/information.html">about</a> | <a href="/view/">browse</a> | <a href="/perl/search/simple">search</a> | <a href="/perl/register">register</a> | <a href="/perl/users/home">user area</a> | <a href="/help/">help</a></div><br /></td> </tr> <tr><td colspan="2"><p><img src="/images/eprints/footerline.gif" width="100%" height="4" /></p></td></tr> <tr valign="top"> <td width="68%" class="footer">Authorised by the University Librarian<br /> © University of Tasmania ABN 30 764 374 782<br /> <a href="http://www.utas.edu.au/cricos/">CRICOS Provider Code 00586B</a> | <a href="http://www.utas.edu.au/copyright/copyright_disclaimers.html">Copyright & Disclaimers</a> | <a href="http://www.utas.edu.au/accessibility/index.html">Accessibility</a> | <a href="http://eprints.utas.edu.au/feedback/">Site Feedback</a> </td> <td width="32%"><div align="right"> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><img src="http://www.utas.edu.au/shared/logos/unioftasstrip.gif" alt="University of Tasmania Home Page" width="260" height="16" border="0" align="right" /></a></p> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><br /> </a></p> </div></td> </tr> <tr valign="top"> <td><p> </p></td> <td><div align="right"><span class="NoPrint"><a href="http://www.eprints.org/software/"><img src="/images/eprintslogo.gif" alt="ePrints logo" width="77" height="29" border="0" align="bottom" /></a></span></div></td> </tr> </table> <!-- #EndLibraryItem --> <div align="center"></div></td> </tr> </table> </body> </html>