Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 201-209.

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. Robert H. Reeves, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed Sept. 23, 2004). Includes bibliographical references.

Thesis (M. Sc. (Ichthyology & Fisheries Science))--Rhodes University, 2005.

A global decline in the lobster fishery has necessitated the growout of wild-caught postlarvae (pueruli) on farms to meet the worlds lobster demand. A limited knowledge on puerulus settlement in the West Coast rock lobster (Jasus lalandii) constitutes a major barrier for J. lalandii culture development in Southern Africa. As an extension of an existing long-term puerulus monitoring program of the Ministry of Fisheries and Marine Resources of Namibia, the present study monitored puerulus recruitment (supply), puerulus condition and juvenile growth of J. lalandii and their relationship with environmental variables on an oyster farm at Lüderitz Bay, Namibia. Implications for lobster aquaculture and fisheries management are discussed. Oyster bags, crates and collectors were sampled daily, weekly and bimonthly, for pueruli and juveniles, respectively, between August 2001 and July 2003 to establish spatialtemporal patterns in their distribution. Animals were transported to the laboratory for morphometric analyses where they were staged as puerulus (Pt = transparent; Pp = pigmented) and juvenile lobsters. The carapace lengths (0.1mm CL) and wet weights (0.01gram) of animals were recorded. Carapace length frequencies were subjected to Modal Progression analysis to identify early juvenile cohorts and calculate their growths. The weight-length ratios calculated and percentage fat content were used as indices of nutritional condition. Seasonal peaks in puerulus and juvenile abundance were estimated using Periodic Regression analysis. The relationships of puerulus and juvenile abundance with respect to sea surface temperature (SST), wind speed-direction, moon phase, swell and tidal range were established using time lag analysis (ADL). Transparent pueruli were randomly distributed on oyster bags and crates, and also between collector sites, suggesting that they have no particular settlement preference for certain areas on these structures (p>0.05; n=150). Pigmented puerulus (p<0.05; n=566) and juveniles (p<0.05; n=3528) preferred structurally complex structures that provided better shelter such as crates, which were more sheltered from sea swells, compared to oyster bags. Among oyster rafts, pigmented puerulus and juveniles preferred occupying the sheltered and centred raft areas, which provided better protection from wave action, compared to exposed raft areas, which were exposed to the incoming swell. Puerulus and juvenile lobster appeared to recolonise adjacent bags and crates, and possibly migrate to the substrate and off the farm due to the disturbance of the habitat during harvesting. The booth crevice collector was more efficient in collecting puerulus possibly due to the high structurally complex habitat and the better shelter they provided compared to the hogshair collector. The occupation of structurally complex habitats by early benthic stages may be related to morphological changes associated with metamorphosis. Puerulus settlement peaked during early spring (August-September) and was related to low sea surface temperatures (12.3°C), strong south winds, and moderate swells in the week preceding settlement. These conditions are synonymous with the “spring upwelling” season of the Lüderitz upwelling cell in the central Benguela current region. Puerulus nutritional condition peaked during this period possibly due to high levels of planktonic food (due to high nutrients from upwelling) that was available to the late stage phyllosoma larvae further offshore. A “good” puerulus settlement year during 2000 was associated with lower than average SST (11.6°C) and strong south winds and was followed by “poor” puerulus settlement years during 2001 and 2002 when higher than average SST were experienced with below average wind speeds experienced during 2001 only. Puerulus of J. lalandii recruited in high numbers into Lüderitz Bay during the new moon, full moon and last quarter moon phases by making use of the increased tides during these phases of the lunar cycle. Peak juvenile abundance during early summer (November-December) lagged by 8 weeks was significantly correlated with peak puerulus abundance. Puerulus size was similar (8.5–9.7mm CL) over the study period. Juvenile cohorts, 9.9-20.6mm CL in size recruited in 2 distinct waves in August 2001-June 2002 and July 2002-February 2003. The 2001/2002 recruits had higher monthly growth increments and better nutritional condition compared to 2002/2003 recruits. Peak frequencies of 2nd moult juveniles (9.9- 10.8mm CL) occurred in September of both recruitment events with nutritional condition being poorest during the 2002/2003 event. The nutritional condition of the settling puerulus did not appear to be related to the subsequent growth of juvenile lobster. These preliminary results suggest that pueruli recruit once a year mainly during late winter/ early spring under conditions typical of coastal upwelling in the Benguela current near Lüderitz. It appears that puerulus settlement is driven by favourable shoreward currents, which help in transporting puerulus to their settlement grounds. Puerulus supply is highly variable between years, which appears to be consistent with a highly variable Benguela environment. The oyster farm supported a substantial standing stock averaging 123 800 lobster per day (range: 22 600-325 300 lobster per day) of which 26 600 were puerulus and 97 200 were juveniles, that may have been harvested once off on any given day during the sample period. Monthly harvesting of the total lobster standing stock during the one and a half year sampling period was just over 2 million lobsters (505 700 pueruli and 1.85 million juveniles) and would potentially have been sufficient seed for a 200 ton lobster production in puerulus lobster growout facilities. In the light of high inter-annual variation in puerulus settlement observed at Lüderitz, the seed supply at the Lüderitz oyster farm is clearly limited and therefore it is prudent that other sites of high puerulus settlement is established before large commercial scale lobster growout can commence. The migration of lobster off the farm suggested that these lobsters potentially recruit to the fishery and therefore harvesting the entire standing stock on the farm may have adverse negative effects on the wild fishery. A policy decision will be required as to whether more efficient harvesting of lobster from the farm should be allowed. If puerulus removal in J. lalandii for aquaculture is allowed in the near future, it should be conducted on an experimental scale or small commercial scale until the potential effects on recruitment into the fishery are clearer.

1) The carpopodite extensor muscle of Carcinus maenas and Homarus americanus demonstrated regional localization of at least three types of fibre: fast phasic, slow tonic and intermediate. A specific area of the extensor, area 1, was identifiable in extensors from different animals and comprised fast phasic fibres in Carcinus and intermediate fibres in Homarus. When the M-C joint of the leg was held at a 90&deg; angle, the sarcomeres in area 1 fibres were at rest length. Measurements of sarcomere length taken in the middle peripheral region were indicative of sarcomere lengths in other regions of the intermoult fibre. 2) The mechanism of growth of the fibres was determined in intermoult animals of increasing size. Fibres increased in length by the addition of sarcomeres and increased in width by an increase in the number of myofybrils. Myofibrils increased in size by the addition of thick and thin filaments in the characteristic lattice arrangement. The number of myofibrils may increase by myofibrillar splitting as has been previously described for vertebrate muscle. Fibre number remained constant with growth of the animal. There was a decrease in mitochondrial density with increase in fibre area. 3) Over ecdysis, fibres lengthened by addition of short sarcomeres to the exoskeletal region of the fibre. During the 3-4 days postecdysial expansion of the exoskeleton, these short sarcomeres increased in length. hypothesis that these short sarcomeres are precursor sarcomeres being added during ecdysis was investigated. When intermoult muscle was held in a stretched position for 2 weeks, there was a regional increase in the length of the muscle similar to the increases found over ecdysis. In contrast, fibre area did not increase over ecdysis. Instead, fibre area increased during the late postmoult and intermoult. The frequency distribution of myofibril size altered over ecdsysis; large myofibrils were more commonly present during premoult than during the immediate postmoult. Lateral stretch on the muscle during ecdysial expansion of the exoskeleton may be the stimulus for myofibrillar splitting. Possible satellite cells were identified in the skeletal muscle fibres-. vitro and jLn vivo radiolabelling techniques were adapted for the carpopodite extensor muscle of Carcinus maenas. The levels of free phenylalanine, total bound protein and phenylalanine bound in the muscle protein increased with size of the muscle. The mean in vitro rate of synthesis or FSR in the intermoult animal was 0.3% per day and the in vivo rate of synthesis at 1.24% per day. The FSR remained constant with size of the extensor muscle in intermoult animals. Fixatives may have an effect on the specific activity in the bound fraction of the muscle which is attributable to binding artifacts of the free amino acids. 5) The levels of phenylalanine in the free pool fluctuated during the moult cycle. The protein/wet weight ratio of the muscle also varied with the moult cycle. Increases in protein during the early postmoult supported other evidence for growth of the muscle over ecdysis. Synthesis rates were raised during the premoult and immediate postmoult period and remained slightly elevated during the late postmoult. These increases in rate corresponded to periods of muscle growth. 6) Autoradiographic techniques combined with measurements of bound specific activity revealed an increase in activity in the exoskeletal or cuticular region of the fibre corresponding to the region of new muscle synthesis over ecdysis. No differences in grain density were found between fast phasic and slow tonic fibres or between the central and peripheral region of the myofibril in intermoult muscle. Regional localization of grains was found at the light microscope level in the Z, I and B bands but no further evidence of this differentiatial labelling was found at the electron microscope level.

Previous studies in localised areas have revealed spatial variability on Nephrops norvegicus population characteristics. In order to investigate this subject in a comprehensive way, a large amount of Nephrops data (catch rates, size compositions, female maturity condition, moult condition and burrow densities) and related sediment data, from different areas and grounds all around Scotland, were assembled and analysed. The available commercial fishery statistics on Nephrops were also used for this purpose. High variability in depth and sediment size composition was found in Scotland, between and within, Nephrops fishing areas. The East cost areas showed less variability than those from the West coast areas both in terms of depth and sediment types. The particle mean size of the sediments (in phi units) was found to be the most appropriate descriptor of sediment granulometry. Well defined relationships were found between the particle mean size and other sediment characteristics. Equations were provided to convert mean to median particle size and mean to percentage of silt and clay. Organic carbon was found to be linearly correlated to the particle mean size but different trend lines were found for the east and west coast. Contradictory trends in the relationships between the sediment size composition and depth suggested a major role of hydrographic and topographic factors in the distribution of the sediments. Large spatial variability in the biological characteristics of Nephrops living at different fishing grounds was found, between and within areas. Burrow density was directly associated with catch rates, and mean sizes were inversely correlated with catch rates. The female size statistics associated with the reproductive condition (e.g. the size at first maturity) were positively significant correlated with the female overall mean size. Populations with lower catch rates exhibited higher growth performance and size structures characterised by larger mean sizes. Females from populations with faster growth became sexually mature at a larger size than those with slower growth.

These (Ph.D.)--Dalhousie University, 2008. / Title from PDF title page. Abstract, table of contents in French and English. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 88-97). Also issued in print.

Thesis (Ph. D.)--Illinois State University, 2000. / Title from title page screen, viewed May 11, 2006. Dissertation Committee: David Borst (chair), Anthony Otsuka, Radheshyam Jayaswal, Paul Garris, David Williams. Includes bibliographical references (leaves 130-135) and abstract. Also available in print.

Thesis (M.S.)--Rhodes University, 2004. / Title from PDF t.p. (viewed on June 9, 2006). Includes bibliographical references (p. 91-104).

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.