Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 63-71. Also available online.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 113-127. Also available online.

Host fishes for the state-endangered Tennessee heelsplitter (Lasmigona holstonia) and state-threatened black sandshell (Ligumia recta) were identified through induced infestations of glochidia on potential hosts. Largemouth bass (Micropterus salmoides), yellow perch (Perca flavescens), convict cichlid (Cichlasoma nigrofasciatum), platy (Xiphophorus maculatus), green sunfish (Lepomis cyanellus), rock bass (Ambloplites rupestris), redbreast sunfish (Lepomis auritus), and white perch (Morone americana) were identified as suitable hosts for L. recta. The banded sculpin (Cottus carolinae) and rock bass were identified as hosts for L. holstonia; striped shiner (Luxilus chrysocephalus), central stoneroller (Campostoma anomalum), and warpaint shiner (Luxilus coccogenis) were identified as potential hosts. Additionally, rock bass and bluegill (Lepomis macrochirus) were identified as potential hosts for the state-endangered spectaclecase (Cumberlandia monodonta), with numerous encysted glochidia present at 11 days postinfestation when the fish died. Recirculating culture systems of different design were tested for suitability in juvenile mussel culture. In one system (high maintenance), juveniles of the wavy-rayed lampmussel, Lampsilis fasciola, were kept in culture dishes, and in the other system (low maintenance), the juveniles were kept in culture beds. At the end of the 16-wk culture period, the 31.3% (± 15.4) survival exhibited in the dish culture system was significantly greater than the 3.1% (± 2.8) survival in the bed culture system (P< 0.01, Tukey-Kramer). However, mussels grown in the bed system exhibited significantly greater growth (1.4 ± 0.50 mm height, 1.8 ± 0.76 mm length) than those grown in the dish system (0.86 ± 0.19 mm height, 1.1 ± 0.27 mm length) (P<0.01, Tukey-Kramer). Using the high maintenance dish culture system and juveniles of L. fasciola, the influence of high (4.1%) and low (2.5 %) organic content in substrate, and high (250 mg/L CaCO₃) and low (50 mg/L CaCO₃) water hardness levels were assessed on growth and survival. After 15 wk, juveniles in the high water hardness treatment exhibited significantly greater survival and growth (44.2 ± 9.3% survival, 1.5 ± 0.28 mm height, 2.1 ± 0.41 mm length) than those in the low water hardness treatment (9.0 ± 7.9% survival, 1.3 ± 0.25 mm height, 1.8 ± 0.37 mm length) (P<0.01, Tukey- Kramer). Juveniles in the high organic substrate exhibited similar growth (1.41 ± 0.24 mm height, 1.96 +- 0.37 mm length) to those in the low organic substrate (1.39 ± 0.28 mm height, 1.94 ± 0.42 mm length). Juveniles grown in high hardness and high organic substrate had similar survival (27.4 +- 9.2%) to those in low organic substrate (25.8 ± 8.1 %). For the culture of L. fasciola juveniles, I recommend using a culture system that is cleaned regularly (weekly), receives a consistent (daily) supply of algal food, has relatively even flow, and from which juveniles are easily sampled. I recommend culturing them in relatively hard water (~ 250 mg/L CaCO₃), in a substratum with some organic content. These recommendations may warrant modification for the culture of other freshwater mussel species. / Master of Science

Growth, mortality, production, spat collection, seasonal cycles of condition index, biochemical composition, carrying capacity of commercial raft culture systems and population genetic characteristics of blue mussel (Mytilus edulis) were studied at different sites in Loch Etive and Loch Kishorn on the west coast of Scotland between May 1993 and May 1995. The main objective of the study was to evaluate current suspended mussel culture production in raft systems and to obtain basic information on the biology and the genetic structure of the two mussel populations in the lochs. There were some water quality differences between the sites in relation to seston, salinity and transparency but not to temperature, particulate organic matter and chlorophylla. When food is available (as particulate organic matter and chlorophyll-a), there was a clear seasonal cycle in mussel somatic growth and shell growth. Mussel growth was relatively high from mid-spring until late autumn, but very slow during the rest of the year. The spring-summer period of rapid shell length and somatic growth coincided with relatively optimum environmental conditions and positive relationships were indicated between growth rates, temperature and salinity, indicating the limiting effect of these two primary factors on growth from late-autumn to mid-spring when there is also a lack of available food. Mussel growth was higher at 2m depth on the raft-rope systems, but in lantern nets experimental growth did not show differences between depths. Growth was found to be similar in the lantern nets and on culture ropes in the two lochs in the first year of experiments (from May 1993 to May 1994). Overall, mean length increments were 31.01mm in Loch Etive and 28.75mm in Loch Kishorn over a 15 month period. The mussels reached marketable size (&gt;50mm) in two years from the known time of spat settlement. A cross-transplantation experiment showed that site rather than stock is the main factor explaining differences in mussel growth in Loch Etive and Loch Kishorn. The position of the mussels within a raft has a significant effect on their growth; mussels at the inflow of a raft have a better growth than those near the outflow (p&lt;0.05) due to greater availability of food. Mean mussel biomass was higher in Loch Kishorn while production was higher in Loch Etive, but there were seasonal and monthly fluctuations in both biomass and production at both sites. Biochemical composition and energy content were similar in both sites, while mussel meat yield and condition indices were significantly higher in Loch Kishom than Loch Etive. Meat content, condition index and carbohydrate values were high during the summer and low from autumn to spring, reaching minimum values in March and April at the time of spawning. Spat settlement occurred in June-July in Loch Etive and June-December in Loch Kishorn. Sea squirt, starfish and eider duck are problems effecting spat collection at the Loch Kishorn site, whereas spat collection in Loch Etive is unaffected by these pests/predators. The carrying capacities for cultured mussels were found to be about 24 metric tons per raft for Loch Etive and 38 metric tons per raft for Loch Kishorn using a particulate organic matter based model; these are reasonable estimates in comparison to the known mussel production levels reported by producers. However, a seston-based model gave an overestimate of carrying capacity for both sites. Cross-transplantation of mussels, electrophoresis and shell morphological measurements showed significant differences between the Loch Etive and Loch Kishorn mussel populations. Mortality rates were higher in transplanted mussels than in the native mussels (p&lt;0.001).

Growth. mortality. production. physiology and seasonal cycles of condition index and proximate biochemical composition of experimental populations of blue mussels (Mytilus edulis L.) were studied at different sites in Loch Etive and Loch Leven on the West coast of Scotland between May 1990 and September 1992. The main objective of the study was to evaluate current suspended mussel culture practices and to establish the basis for their possible integrated cultivation with salmon cage fanning. In addition. a preliminary investigation on employment of the . Charm IT' system as a rapid method for detecting residues of drugs used for treating cultured salmon in the tissues of mussels was carried out. There were some differences between sites in salinity, seston and particulate organic matter, but not in chlorophyll-a. Food availability (as particulate organic matter and chlorophyll-a) showed a clear seasonal cycle and in consequence growth of mussels were relatively rapid from late-spring until mid-autumn (g 6 months) and very slow or absent during the rest of the year. This period of rapid length and tissue growth coincided with relatively optimum environmental conditions and there were apparent positive relationships between monthly growth rates and temperature and chlorophyll-a values, indicating the limiting effect of these two primary factors on growth during autumn-winter and even in early spring. Almost all growth parameters examined were showed significant differences between the lochs. Growth performance of both native and transplanted mussels in Loch Leven was quite poor. Overall annual length increments were 25.1-25.9 mm at sites in Loch Etive and Dunstaffnage Bay, but 20.1-22.8 mm in Loch Leven. A crosstransplantation experiment showed that site rather than stock is the main reason for differences in growth parameters between Lochs Etive and Leven. These observed growth differences between sites and stocks were also confirmed by physiological measurements and estimated growth potential or scope for growth. Growth of mussels at salmon farms was faster than at neighbouring mussel farms during two annual experiments, but only meat weight at one salmon farm during experiment I, and length and live weight at the salmon farm in Loch Etive as well as all growth parameters at the salmon fann in Loch Leven during experiment II were significantly greater (}>sO.05). These differences were most likely a result of high particulate organic matter levels at salmon fanns. Similar to growth, biomass and production, the condition index and biochemical composition of mussels showed a clear seasonal cycle. Meat content, condition index and glycogen values were high during summer, started to decline in late autumn and reached minimum values in April before showing maximum increases in May. This reflects the typical storage and reproductive cycle of mussels in Northern Europe: accumulation of reserves during summer and their utilization during winter and early spring as energy resources for metabolism and reproduction. This cycle clearly showed that the main spawning of mussels on the West coast of Scotland occurred during March-May, and primary spat settlement from June to August. Heavy losses occurred from French socks, causing substantial amounts of eliminated biomass during experiment I, but when these fall outs were eliminated during experiment II by using lantern nets, it was clear that natural mortality rates were quite low and similar at all sites. Apart from growth characteristics and physiological responses, there were persistent morphological differences between the Loch Etive and Loch Leven populations. Cross-transplantation and physiological measurements after various acclimatization periods showed that, while morphological differences might be related to genetic origin, all other differences between the two popUlations are governed by environmental factors. The practical implications of these findings for developing suspended mussel culture on the West coast of Scotland and the possibility of a simple integrated salmon-mussel fanning system, which could be effective in controlling potential eutrophication from intensive salmon cage fanning and the removing large amounts of organic matter by mussels leading alterations in ecosystem, are discussed. A preliminary study with the Chann II Test has showed that the system is not so appropriate method as expected for screening mussel tissue sampled straight from the field, since mussel tissues require purification due to interference from bacteria or microbial detritus, before screening.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 78-90.

Graduation date: 2006 / This study investigated whether a device commonly used to measure settlement of mussel larvae for ecological studies, the Tuffy™, functions uniformly whether placed in a bed of filamentous algae or on bare rock. During the summers of 2004 and 2005, the number of mussel larvae settling on Tuffys in patches of the filamentous algae Endocladia muricata and Neorhodomela larix, known to be natural substrata for settlement of mussels, was shown to be the same as on Tuffys on adjacent patches of bare rock. The data provide no evidence that adjacent filamentous algae affects settlement to Tuffys and support the utility of this technique for measuring the intensity of larval settlement.

Thesis (MScAgric)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: This study examines the role of contracting in reducing transaction costs in smalIscale mussel farming in Saldanha Bay. Masiza Mussel Growers (Masiza), an initiative by the public and private sector to address the imbalances of the past through entrepreneurial development, are used as a case study hence a case study approach is followed. Two transactions were considered, one between Masiza and Blue Bay Aqua Farm (Blue Bay) and another between La Vie Sea Food Products (La Vie) and Masiza. These transactions form the basis for analysis. Market risks, uncertainties, environmental risks, information incompleteness, illiteracy, limited technical knowledge of farming, lack of appropriate infrastructure and lack of transport facilities are identified and examined as possible sources of transaction costs that constrain the existing supply chain relationship. The study shows that asset specificity, time specificity, and site specificity playa positive role in the supply chain as they result in relative dependency amongst parties. Opportunistic behavior within the existing supply chain is neutral, but appears to be relatively high on the spot or fresh live market. Characteristics of market transactions for mussels and associated transaction costs suggest that fresh-live spot market trading for Masiza is difficult to attain. This therefore motivates parties (Masiza) to contract or vertically integrate, as it is costly and risky to rely on spot live markets. Interviewees (Masiza) pointed out that the benefits associated with contract farming outweigh the transaction costs associated with this governance structure. Hence a market specification contract with the La Vie (a processing company), and a production management and resource provision contract with Blue Bay (a larger producer) were designed. They reduce transaction costs associated with fresh-live markets and ensure a more stable and reliable market for growers. / AFRIKAANSE OPSOMMING: Die studie ondersoek die rol van kontraktering in die vermindering van transaksie koste vir klein skaal mossel produsente in Saldanha baai. Die Masiza Mussel Growers (Masiza) word as gevallestudie gebruik. Twee transaksies met o.a. Blue bay Aqua Farm (Blue Bay) en La Vie Sea Food Products (La Vie) was ter sprake en laasgenoemde het as basis vir die analise gedien. Mark risiko, onsekerheid, omgewings risiko, gebrekkige informasie, ongeletterdheid, beperkte tegniese kennis, beperkte infrastruktuur en beperkte verroer fasiliteite is geidentifiseer en ondersoek as moontlike oorsake van hoë transaksie koste wat die huidige aanbod ketting strem. Die studie toon aan dat interafhanklikheid tussen die betrokke partye deur bate, tyd en area spesifisiteite bevorder word en dus 'n positiewe rol in die aanbod ketting speel. Opportunistiese gedrag binne die bestaande aanbod ketting is neutraal, maar blyk hoog te wees in die vars mark. Transaksie kostes en eienskappe blyk beduidende beperkinge te wees vir kleinskaal mossel produsente om aktief deel te neem in die mark. Die opstel van kontrakte (of vertikale integrasie) blyk dus 'n uitkoms te wees. Respondente het aangetoon dat kontrak boerdery voordelig blyk te wees. Laasgoemde het tot die ontwikkeling van mark kontrakte met die La Vie ('n verwerkings maatskappy) asook produksie bestuur en hulpbron voorsiennings kontrakte met Blue Bay ('n groot kommersiële produsent) gelei. Die kontrakte beperk transaksie koste vir die vars mark en verseker 'n stabiele en betroubare mark vir produsente. 'n Transaksie koste analiese word gebruik om transaksie kostes te ondersoek en te verifieer binne die industrie.

Frente ao crescimento acelerado da maricultura estão surgindo dificuldades entre as instituições governamentais para promover o desenvolvimento sustentável do setor. Com isso, aumenta cada vez mais a necessidade de se estudar a influência dos cultivos sobre os ambientes nos quais eles estão inseridos. Neste contexto, este estudo teve como objetivo determinar experimentalmente a produção de resíduos sólidos gerados pelos mexilhões cultivados na Praia da Cocanha, área com o maior adensamento de cultivos de mexilhões no litoral de São Paulo. Para isso, mensalmente entre fevereiro de 2008 e janeiro de 2009, foram desenvolvidos e executados experimentos com mexilhões de cultivo visando a quantificação dos resíduos sólidos gerados. Os resultados indicaram que a quantidade de resíduos variou significativamente conforme o tamanho dos organismos e ao longo do tempo. As variáveis oceanográficas variaram ao longo do ano sem um padrão definido e não explicaram a produção de resíduos sólidos. A produção anual estimada para a área foi de 233,8 à 718,9 (415,1 ±174,7) toneladas de resíduos sólidos conforme o adensamento dos cultivos. Em função disso, são necessários estudos específicos sobre as características hidrodinâmicas do local para que se possa avaliar a magnitude e a localização dos impactos causados pela atividade no local. / Due to the fast aquaculture\'s growth in Brazil, governmental institutions are facing difficulties to promote a sustainable development of the activity. With this, there is an increasing necessity of researches to determine the influence of mussel cultures on the environment. In this context, this study aims to experimentally determine solid waste production from mussels\' culture in Cocanha Beach, the largest mussel culture site in São Paulo State\'s coast. For this, monthly experiments with cultivated mussels where carried out from February/2008 to January/2009 to quantify the amount of solid waste produced. The results showed that the amount of solid waste produced had a significant variation with the size of the organisms and also through the year. The oceanographic parameters also varied throughout the study period but could not explain the variation in solid waste production. Annual total production was estimated in 233,8 to 718,9 (415,1 ±174,7) tons of solid waste, which varied in relation to the density of the culture. Due to these findings, further specific researches concerning local hydrodynamic characteristics are requested in order to determine the exact location and range of the area that suffers the impact derived from local aquaculture activities.

Frente ao crescimento acelerado da maricultura estão surgindo dificuldades entre as instituições governamentais para promover o desenvolvimento sustentável do setor. Com isso, aumenta cada vez mais a necessidade de se estudar a influência dos cultivos sobre os ambientes nos quais eles estão inseridos. Neste contexto, este estudo teve como objetivo determinar experimentalmente a produção de resíduos sólidos gerados pelos mexilhões cultivados na Praia da Cocanha, área com o maior adensamento de cultivos de mexilhões no litoral de São Paulo. Para isso, mensalmente entre fevereiro de 2008 e janeiro de 2009, foram desenvolvidos e executados experimentos com mexilhões de cultivo visando a quantificação dos resíduos sólidos gerados. Os resultados indicaram que a quantidade de resíduos variou significativamente conforme o tamanho dos organismos e ao longo do tempo. As variáveis oceanográficas variaram ao longo do ano sem um padrão definido e não explicaram a produção de resíduos sólidos. A produção anual estimada para a área foi de 233,8 à 718,9 (415,1 ±174,7) toneladas de resíduos sólidos conforme o adensamento dos cultivos. Em função disso, são necessários estudos específicos sobre as características hidrodinâmicas do local para que se possa avaliar a magnitude e a localização dos impactos causados pela atividade no local. / Due to the fast aquaculture\'s growth in Brazil, governmental institutions are facing difficulties to promote a sustainable development of the activity. With this, there is an increasing necessity of researches to determine the influence of mussel cultures on the environment. In this context, this study aims to experimentally determine solid waste production from mussels\' culture in Cocanha Beach, the largest mussel culture site in São Paulo State\'s coast. For this, monthly experiments with cultivated mussels where carried out from February/2008 to January/2009 to quantify the amount of solid waste produced. The results showed that the amount of solid waste produced had a significant variation with the size of the organisms and also through the year. The oceanographic parameters also varied throughout the study period but could not explain the variation in solid waste production. Annual total production was estimated in 233,8 to 718,9 (415,1 ±174,7) tons of solid waste, which varied in relation to the density of the culture. Due to these findings, further specific researches concerning local hydrodynamic characteristics are requested in order to determine the exact location and range of the area that suffers the impact derived from local aquaculture activities.