Dissertations / Theses on the topic 'Crustacean Fisheries'

Molecular ecology is one of the most important branches of evolutionary biology, and it uses the advantages of molecular techniques such as PCR-RFLP, sequencing, microsatellite analysis, and most recently the introduction of next generation sequencing, to address outstanding issues in the fields of population genetics and phylogeny. The genomic approach has been influential in providing new information relevant to traditional questions in ecology, such as genetic differentiation, speciation, species adaptation and others. The rationale of the present thesis was to incorporate the advantages of both the PCR-RFLP and sequencing techniques to gain information on the genetic variability of two commercially-important crustacean species, namely the Norway lobster Nephrops norvegicus and the giant freshwater prawn Macrobrachium rosenbergii. Nephrops norvegicus exhibits large morphological variability even between adjacent populations. The first objective of this thesis was to investigate the genetic variability of N. norvegicus from three localities, the Clyde Sea area and North Minch (North Sea) as well as Icelandic waters. The phylogeographic study found no significant differentiation between populations from the studied areas (FST: 0.01819). This finding is consistent with outcomes from previous studies that N. norvegicus populations were not geographically structured. Outcomes from the present study strongly suggest that environmental factors, rather than genetic factors, are more likely to play a more significant role in the high morphological differentiation observed in this species. A study of the most important freshwater crustacean species, Macrobrachium rosenbergii was then undertaken as a contribution to understanding the most complex biogeography in the world, the Indo Australian Archipelago (IAA). The IAA has incredible species richness and endemism and is the location of 4 out of 25 world’s biodiversity hotspots, namely the Sundaland, the Philippines, Indonesia and Wallacea. Within the IAA is the location of Wallace’s line and Huxley’s line, the most abrupt faunal transition in the world that lies between the Sunda and Sahul shelves. The studied species used in the present thesis, M. rosenbergii is an ideal model species as it has a wide geographical distribution across the IAA. The present phylogeographic study screened the COI segment using the sequencing technique to study M. rosenbergii populations collected from eight locations in Malaysia in the peninsular and east of Malaysia. These populations exhibited high genetic differentiation (FST: 0.62503) mainly due to the sample from Sabah. However, the adjacent population (Sarawak) was similar to that in Peninsular Malaysia, even though Northern Sarawak showed sub-population differentiation from the main cluster (cluster I) indicating that the genetic diversity of Northern Sarawak was more restricted. Beside, cluster II observed in the study indicated and confirmed the recent aquaculture activities of restocking the Kedah, Perak and Sarawak populations. Knowledge of the levels of genetic differentiation in N. norvegicus and M. rosenbergii could assist in the management of the species. N. norvegicus could be managed as one stock and conservation and recovery programme could be carried out based on the knowledge that all studied populations exhibited lack genetic differentiation within and between populations. In contrast, M. rosenbergii that possessed high level of genetic differentiation have to be managed separately, especially for a unique population such as the one in Sabah. The outcomes of this study could also be useful for future research in the conservation of wild population, as well as aquaculture management and product improvement purposes. The finding of Sabah as a unique population could potentially be useful for aquaculture improvement programmes. One of the most important aspects is to see whether Sabah population possessed high resistant to the disease infection. A preliminary study was conducted to investigate the susceptibility of a Malaysian wild population of M. rosenbergii to infection by the human food-poisoning bacterium V. parahaemolyticus. Nonetheless, the virulence stage of the bacterial strain, the status of the immune system of the host, the size and age of the experimental animals as well as the dose of injected bacteria might all have contributed to the inconclusiveness of the results. However, the principle of screening wild populations for disease resistance is sound, and may lead to improvements in the quality of the broodstock used in the Malaysian aquaculture industry.

This work investigates the factors controlling production and determines the biophysical properties of cross-linked protein coated microencapsulated diets, with a view to enhancing their acceptability and digestibility to omnivorous and carnivorous larvae. To estimate optimal feed larvae of Penaeus monodon on microencapsulated diets, facilitate live transportation and add to the biological knowledge of the species, the relationship between metabolic rate/temperature and energetics of the larval stages were investigated. Also described, are laboratory growth and survival trials with P. monodon larvae fed on cross-linked protein microencapsulated diets. Success with P. monodon larvae, led to investigations on acceptability, growth and energetics of juvenile P. monodon reared on an artificial diet. For comparison, a similar line of approach was adopted with the carnivorous larvae of Homarus gammarus. Studies on the physiological energetics of the larvae were followed by investigations on acceptability, growth and digestibility of artificial diets fed to H. gammarus larvae. The final discussion attempts to correlate the contrasting larval growth/survival results to the different energy strategies adopted by the larvae.

The crabs Cancer pagurus (L) and Necora puber (L) are exported live, in bulk, from the UK to various continental countries. The success of this relatively new trade is marred by the incidence of mortalities and impaired quality of the delivered product. These studies addressed various causes - procedural and biological - of these events.Descriptions are given of detailed examinations of handling and other marketing protocols for both species from point of capture to arrival at continental dealer's premises. Such examinations were made with the help of a number of major dealers in the UK, Spain and France and included studies of handling, packing, holding and transportation methods, physical damage assessments before and after consignment, and chemical and biochemical analyses of seawater and blood samples.Dissolved ammonia levels were found to increase greatly in the fixed volume water of vivier tanks and this was found to be matched by correspondingly high blood ammonia values of the contained animals. The measurement of both free ammonia and ionic ammonia efflux rates of juvenile and adult Cpagurus and Npuber in media with high dissolved ammonia levels was investigated and was found to be related to concentration gradients between the internal and external media. The fluxes could be explained on the basis of diffusion down concentration gradients. When animals were transferred to media with higher ammonia levels than those in blood, a cessation of efflux, or even a net influx of ammonia (NH4+) occurred.During emersion, blood ammonia concentration rose. Such accumulated ammonia was very rapidly off loaded when the animals were re-immersed.The data produced has been discussed in the context of crustacean physiology and of improving the expectations of delivering a live, quality product after journeys of several days.

The diversification of current aquaculture practise in South Africa is crucial for the future development of the industry. The rock lobster, Jasus lalandii has been identified as a possible candidate species for shore based culture in systems similar to those used for abalone farming. Reduced Total Allowable Catch (TAC's) and an increased minimum legal size were implemented as management strategies to relieve fishing pressure on natural stocks of J. lalandii, and in turn led to increased market demand and a possible niche for farmed lobsters. High puerulus settlement along the Namibian coast, together with other favourable aquaculture attributes, indicate that the commercial grow out of wild harvested juveniles could be feasible. The aim of study was to investigate the feasibility of growing out rock lobsters in shore based systems in Namibia and South Africa. The experimental objectives of the project were to investigate the nutritional requirements, as well as the effect of stocking density and tank design on growth and survival of J. lalandii. The economic viability of shore based rock lobster farming was then evaluated based on the experimental results and typical capital requirements of an abalone farm in South Africa. Puerulus and early juvenile rock lobsters were collected in Luderitz, Namibia and transported to HIK Abalone Farm in Hermanus, South Africa where they were acclimated in black fibre glass tanks in a flow through system. The pueruli were stocked at 50, 75, 100 and 125/m² and early juveniles at 20, 30, 40 and 50/m² to test the effect of density on growth and survival. A comparative dietary study with both size classes was conducted using a mussel diet (Choromytilus meridionalis and Mytilus galloprovincialis), a commercial shrimp feed diet and a rotational diet comprising both mussels and shrimp feed. Tanks provided with "v-shaped" asbestos hides, PVC hides and no hides were compared to test the effect on growth rate and survival of pueruli. All treatments were conducted in triplicate. Temperatures were recorded twice daily while water quality parameters were tested every second week. The results indicate that density had a significant effect on growth and survival on post-pueruli. An initial stocking density of 75 post-pueruli/m² is regarded as optimal both in terms of the growth rate and biomass production per tank. No differences in growth and survival rates were attained in the early juvenile size class. This indicates that higher densities can be used to rear juvenile J. lalandii. No significant differences were obtained in growth rate when reared under different hide conditions although asbestos hides yielded significantly higher survival rates (93.3 %) compared to the tanks provided with PVC hides (74.04 %) and no hides (77.8 %, p≤0.05). As a result of the high survival rate observed in tanks provided with "V-shaped" asbestos hides, these tanks also yielded higher biomass production per tank (297.8 grams) compared to the tanks provided with PVC hides and no hides (261.09 and 260.5 grams respectively). In the diet trials, growth rates of post pueruli and juvenile lobsters fed the mussel and rotational (mussel and shrimp feed) diets did not differ significantly, however, growth rates of lobsters fed the shrimp feed only diet was significantly lower than both the mussel and rotational diets (p≤0.05). Lobsters fed the mussel diet yielded significantly higher survival rates compared to lobsters fed either the rotational diet or shrimp feed diet only. An imbalance in the fatty acid profile of the shrimp feed could have been a major contributing factor to the poor growth and survival in lobsters fed the shrimp feed only diet as the level of linoleic acid (LOA) was exceptionally high resulting in a high (n -6):(n-3) ratio (1.01) compared to the mussel and rotational diets (0.17 and 0.56 respectively). The low level of arachidonic acid (ARA) in the shrimp feed diet could be a further contributing factor explaning for the poor growth and survival of juvenile rock lobsters. An economic feasibility study was conducted at the end of the experimental phase by modelling a hypothetical shore based rock lobster farm. A projection of production costs and revenues was based on the typical costs of a shore based abalone farm and the current market prices for wild harvested J. lalandii. The economic viability was evaluated using benefit-cost ratios, payback period, internal rate of return and breakeven analysis. Sensitivity analyses revealed that the projected lobster growth and survival rates were the main biological factors influencing the economic feasibility of the hypothetical rock lobster farm. An assumed four year grow out period at a low stocking density yielded more lucrative internal rate of return (IRR), benefit-cost ratio, payback period and net present values (NPV) than a five year grow out period at a high density. The four year grow out scenario proved to be more robust to the fluctuating Rand/US$ exchange rate and could accommodate a lower lobster survival rate. Results presented in this study indicate that rock lobster farming is a marginal commercial prospect based on current production performance and costs. Further research to develop effective puerulus collection techniques as well as to make lobster grow out technology more cost effective is required.

The edible mud crab, genus Scylla, is important to fisheries and aquaculture throughout the Indo Pacific region, but its taxonomic status has been confused for decades and a new classification has only recently been proposed. This project was undertaken to investigate the species status of mud crabs in Southeast Asia, with a view to deciding whether two sympatric morphs of Scylla found in Ban Don Bay, Surat Thani Province, Thailand, are two separate species. A further aim was to elucidate any possible pre-zygotic reproductive isolating mechanisms (RIMs) and ecological features that maintain the apparent sympatry between these two morphs. Mud crabs were collected from a primary site (Surat Thani, Thailand) as well as from six other locations in Thailand, Vietnam, Malaysia and Bangladesh. Crab samples from the latter sites were used selectively to provide a comparison to the primary study site. Descriptive taxonomy, multivariate morphometrics and allozyme electrophoresis were used to a) determine the number of species present within the crab samples collected; b) to ascertain which species they represent; c) to discover any geographical variation between locations sampled; d) to produce a possible phylogeny that summaries the relationship between Scylla species; and e) to look for pre-zygotic RIMs to explain the sympatry of the two morphs in Surat Thani. Findings from the present study reinforce the recent revision of the taxonomy of the genus Scylla into four species, S. serrata, S. olivacea, S. tranquebarica and S. paramamosain and provides new information on two of the four species which are dominant within Southeast Asia, including Ban Don Bay, Surat Thani Province, S. paramamosain and S. olivacea. Population studies showed both genetic and morphological differentiation between conspecific populations of S. paramamosain and S. olivacea, indicating stock structure for each species, although there is some disparity between morphological and genetic distances for S. paramamosain. This is discussed in relation to the effects of larval dispersal mechanisms and the subsequent recruitment of juvenile crabs. Phylogenetic interpretation of both genetic and morphological characters revealed that both S. serrata and S. olivacea are the most diverged of the four Scylla species; however, the direction of evolution is open to interpretation and the evidence for either S. olivacea or S. serrata as the more primitive species are discussed. Reproductive studies on the two mud crab species found in Surat Thani revealed no physical barrier to hybridization. Both species have a protracted breeding season which continues throughout the year. However, the size at first sexual maturity was significantly smaller for S. olivacea when compared to S. paramamosain. This and other potential mechanisms that may maintain these two species sympatrically are discussed. The clarification of four Scylla species, and the establishment of diagnostic genetic and morphological characters that can be used to identify them, means that research can now focus on both the ecology and life history of these closely related species. Such information is needed urgently with respect to fisheries management as well as to understanding the environmental requirements of each species in order to develop their potential for aquaculture.

Orientador: Antonio Leão Castilho
Resumo: Os siriboias são crustáceos pertencentes à ordem Stomatopoda e conhecidos pelo segundo toracópode modificado em garra raptorial, capaz de golpear e quebrar conchas de moluscos, e capturar suas presas. Podem ser separados em dois grupos de acordo com a morfologia das garras: o grupo esmagador, que desfere golpes em sua presa similares a socos de alta potência, e o outro grupo, perfurador, que perfura a presa com as projeções pontiagudas localizadas no dáctilo, último segmento da garra. Existem frequentes relatos anedóticos sobre acidentes em humanos causados por esses crustáceos, mas as informações são imprecisas e muitas vezes o animal não é corretamente identificado pelas vítimas. Este estudo apresenta o relato de 23 pescadores de Ubatuba - São Paulo, que afirmam considerar o siriboia perigoso e que evitam contato direto por conhecerem o risco que o animal oferece, e que os acidentes costumam acontecer com pessoas pouco familiarizadas com o crustáceo. Inclui um relato de lesão causada pelo urópode, informação não documentada anteriormente, e quatro relatos documentados de lesões causadas pelas garras em seres humanos. O estudo resultou ainda em um material informativo sobre os siriboias e prevenção dos acidentes.
Abstract: Siriboias are crustaceans belonging to the order Stomatopoda that are known for the second thoracopods modified to raptorial claws, capable of striking and breaking shells of molluscs and capturing their prey. They can be classified in two groups according to the morphology of the claws: the smasher group, which strikes its prey similar to high-powered punches, and the spearer, which pierces the prey with pointed projections located in the dactyl, last segment of the claw. There are frequent anedoctal reports of human injuries caused by these crustaceans, but the information is inaccurate and often the animal is not correctly identified by the victims. This study presents tertimony of 23 fishermen from Ubatuba - São Paulo, which claim to consider the siriboia as dangerous animals and avoid direct contact, due to know the risk offered. The injuries usually happen in people unfamiliar with the crustacean. It includes one report of an injury caused by the uropod, previously undocumented information, and four documented reports of human injuries caused by the claws. The study proposes informative material about the siriboias and the prevention of injuries.
Mestre

The blue crab, Callinectes sapidus, represents an ecologically and economically important component of marine and estuarine ecosystems. In Florida, blue crab landings accounted for $9.6 million dollars during the 2010 fishing season. Accurate stock assessments for this valuable fishery are essential. Age is a critical biological component of accurate stock assessments; however, blue crabs and other crustaceans are especially difficult to age because of the complex nature of discrete growth. Biochemical extraction of an aging pigment, lipofuscin, was developed using blue crab eyestalks. The current study investigated the effects of freezing preservation on lipofuscin extracts and examined whether the extraction methodology, developed by Chesapeake Bay researchers, was useful for aging Tampa Bay blue crabs populations. Significant differences in lipofuscin index were found between samples frozen (2 weeks at -80°C) prior to analysis and those processed and assayed immediately (p < 0.001). Quarterly assays of the cohort of known-age individuals revealed a negative linear trend (y = -0.12x + 0.49, p < 0.001) in lipofuscin index over a 12-month period. This result suggests that extraction of lipofuscin is not appropriate for age determination of Florida blue crabs. Investigations into possible causes of the negative trend in lipofuscin suggest this method deserves further examination and refinement before it is acceptable as a reliable method for age determination in Florida blue crabs. Growth data of the known-age population collected during this study revealed that blue crabs in Tampa Bay can reach exploitable size in under sixth months and female crabs can reach sexual maturity within seven months of hatching. These growth patterns have the potential to enhance future Florida stock assessments.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Artemesia longinaris Spence Bate, 1888 é considerada uma espécie monotípica endêmica das zonas costeiras do Atlântico Sul Ocidental. Vem sendo recentemente explorada comercialmente devido à queda nos estoques dos camarões de maior interesse comercial. Esse estudo visou comparar a distribuição espaço temporal da A. longinaris em um intervalo de 20 anos (novembro/1988 a outubro/ 1989 e novembro/2008 a outubro/2009) na Enseada da Fortaleza, em Ubatuba, São Paulo. Em ambos os períodos os indivíduos e fatores ambientais (temperatura e salinidade da água de fundo e superfície, sedimento) foram coletados em 7 transectos. Uma RDA foi feita para relacionar os fatores ambientais com a abundância dos indivíduos. O teste de Mann-Whitney foi realizado para comparar fatores ambientais e abundância dos indivíduos entre os dois períodos. Foram coletados de 3088 espécimes no primeiro período e 1252 no segundo, não havendo diferença significativa entre os períodos (p>0,05). Apesar de não apontada estatisticamente houve uma redução do número de indivíduos entre os períodos. Segundo resultados da RDA, uma forte correlação negativa entre a abundância e a classe C (silte+argila) do sedimento, mostrou que o aumento desse tipo de sedimento no segundo período, pode ter contribuído para a redução do número de indivíduos. Aliado a isso, houve menores reflexos da massa ACAS nesta enseada, ocasionando uma redução do número de indivíduos. Esta massa de água reduz as temperaturas de fundo, sendo que a espécie em estudo possui uma história evolutiva vinculada a águas oceânicas frias. Além das condições do sedimento e reflexos da ACAS, a intensa atividade de pesca de arrasto de camarão na região de Ubatuba pode ter contribuído para a redução do número de indivíduos, pois como já é sabido, a pesca de arrasto é considerada uma atividade predatória e causa desestabilização da comunidade bentônica. Em ambos os períodos a espécie se concentrou nos transectos mais profundos (I, VI e VII) onde as características ambientais eram mais favoráveis (temperatura baixa e salinidade alta). O conhecimento sobre a distribuição ecológica desta espécie é importante para que haja um manejo sustentável dos estoques pesqueiros. A Enseada da Fortaleza é desde 8 de outubro de 2008, uma Área de Proteção Ambiental (APA), que visa a preservação dessa biodiversidade. Estudos futuros poderão mostrar se o estoque do camarão A. longinaris está se recuperando devidos às medidas de proteção estabelecidas na região.
Artemesia longinaris Spence Bate, 1888 is considered a monotypic species endemic to the coastal areas of the Western South Atlantic. It has recently been commercially exploited due to the fall in stocks of shrimps of major commercial interest. This study aimed at comparing the temporal distribution of A. longinaris over a period of 20 years (November / 1988 to October / 1989 and November / 2008 to October / 2009) at Fortaleza Bay in Ubatuba, São Paulo. In both periods the individuals and environmental factors (temperature and salinity of the bottom and surface water, sediment) were collected in 7 transects. An RDA was made to relate environmental factors to the abundance of individuals. The Mann-Whitney test was performed to compare environmental factors and abundance of individuals between the two periods. There were collected 3088 specimens in the first period and 1252 specimens in the second, with no significant difference between the periods (p> 0.05). Although not statistically indicated, there was a reduction in the number of individuals between the periods. According to the results of the GDR, a strong negative correlation between the abundance and class C (silt + clay) of the sediment showed that the increase of this type of sediment in the second period may have contributed to the reduction of the number of individuals. Along with this, there were smaller reflexes of the ACAS mass in this cove, causing a reduction in the number of individuals. This body of water reduces background temperatures, and the species under study has an evolutionary history linked to cold oceanic waters. In addition to the ACAS sediment and reflex conditions, the intense shrimp trawling activity in the Ubatuba region may have contributed to a reduction in the number of individuals, since, as is well known, trawling is considered a predatory activity and causes destabilization of the benthic community. In both periods the species was concentrated in the deeper transects (I, VI and VII) where the environmental characteristics were more favorable (low temperature and high salinity). Knowledge about the ecological distribution of this species is important for sustainable management of fish stocks. The Fortress Cove is since October 8, 2008, an Environmental Protection Area (APA), which aims to preserve this biodiversity. Future studies could show whether the shrimp A. longinaris stock is recovering due to the protection measures established in the region.
2015/13607-6

The conservation of species relies on a deep knowledge of biology of the species concerned, as well as on the identification of reproductively isolated units, which are genetically different from one other (genetic stocks). Red shrimps, Aristeus antennatus and Aristaeomorpha foliacea, are commercially important decapods with a large distributional range in the Mediterranean Sea (MED), Atlantic Ocean (AO) and Mozambique Channel (MOZ). The genetic analysis of harvesting grounds of A. antennatus and A. foliacea has allowed identify four genetic stocks within each species and sampled area. The Strait of Gibraltar, the Strait of Sicily and the Peloponnesian gyre were identified as major barriers to gene flow within the Mediterranean Sea and adjacent waters. Furthermore, A. antennatus was identified as a monophyletic species whilst in A. foliacea three genetic lineages were detected, one of which presented multilocus support, so as to be considered a different genetic species.
La conservació i gestió d’espècies depèn d’un bon coneixement de la seva biologia així com de la identificació d’unitats reproductivament aïllades i genèticament diferenciades (estocs genètics). Les gambes vermelles, Aristeus antennatus i Aristaeomorpha foliacea són decàpodes marins amb un alt valor econòmic i un ampli rang de distribució en el Mar Mediterrani, Oceà Atlàntic i Oceà Índic. L’anàlisi genètic dels caladers més importants d’A. antennatus i A. foliacea mitjançant diversos marcadors moleculars ha permès la identificació de quatre estocs genètics en cadascuna de les espècies. L'Estret de Gibraltar, l’Estret de Sicília i el gir del Peloponès es varen identificar com barreres geogràfiques i hidrogràfiques que causen restricció al flux gènic dintre del Mediterrani i amb aigües colindants. D’altra banda, els resultats revelen el monofiletisme d’A. antennatus, i l’existència de tres llinatges en A. foliacea, un dels quals presenta suport multilocus per a ser considerat una espècie genètica diferent.

Energetics of a few Marine crustaceans The thesis is composed of 9 chapters with introduction and material and methods forming chapters 1 and 2 respectively. Chapters 3,4 and 5 deal with different aspects of energetics of the spiny lobster, P.homarus. In chapters 6,7 and 8 the energetics of the prawn, P.indicus are documented along with comparison with that of the spiny lobster. The summary of the work is given in Chapter 9.

The lerm Cladocera was coined by Latreille (829) and it is de ri ved from the Greek words Klados (= branch) and Keras (= horn), afler the two branched second antennae, which are the chief organs of locomotion in these animals. An exhaustive r eview of literature concerning the 'Water Fleas' (cladocerans) has recently been provided by Sharma (991). It would be redundant to go over the ground once again. Neverthe less, a brief survey of the history of work on the systematics of Cladocera seems warranted in this thesis. In the twelfth edition of the "Syslema Naturae" Linne (1767) grouped all Branchiopoda known lo him under one genus , Monoculus (= wilh one eye). But the outline of our present systematical arrangement was given by Huller (1785), who was the first to subdivide Linne's Honoculus into several genera: Daphnia, Lynceus and Polyphemus. Latreille (1817) used Huller's syslem and called the Branchiopoda (= Entomostraca Huller) the fifth order of lhe Crustacea. In 1829 he distinguished the Branchiopoda (= gill feet) as the first order within the Entomostraca; the latter was, in this new edition, the second main

Fish and fishery products are one of the most widely traded food items of world and play a pivotal role in the global food and nutritional security. Fisheries constitute an important sector in many maritime nations, not only as a major food source but also as a generator of foreign exchange earnings and employment. Fish contributes 17% of the global population’s intake of animal protein and provides essential minerals, vitamins and omega-3 fatty acids (FAO, 2014). The fisheries sector is a source of employment for more than 200 million people of worldwide (FAO, 2011). In comparison to the other sectors of the world food production, the fisheries and aquaculture sectors are poorly planned and inadequately funded (USAID, 2011). The capture fisheries sector is one of the fastest growing food sectors in India, in addition to aquaculture. The country also has a significant role in global fisheries as the second largest producer of fish in the world. In India, marine fishery sector is largely constituted by capture fisheries. The present annual production is about 3.78 million tonnes (mt), forming 85.7% of the potential yield of 4.41 mt, the split up being, 2.13 mt of pelagic, 2.07 mt of demersal and 0.22 mt of oceanic resources (DAHDF, 2013; CMFRI, 2014).

The present study deals with a general introduction which outlines the objective of the study providing an exhaustive review of works on crabs with particular reference to deep-sea forms. In the first section, Taxonomy and Geographical disribution of the crab are dealt with. The species is described in detail based on several male and female specimens obtained from the pelagic and bottom collections, and its identity in Indian waters is established. It is also distinguished from a closely allied species so far not reported from Indian waters. The second section comprises the biology of the species and it is dealt with under four subheading, namely Habit and Habitats, Reproduction, Food and feeding and Proximate composition. The different habitats occupied by juveniles, subadults and adults of the species have been described and discussed in the light of available information on differential distribution of other related species. The reproductive biology is described in various details touching on gross anatomy and histology of the reproductive systems, spermatogenesis, oogenesis, size at maturity, ovarian maturation process, fecundity, egg carriage and breeding. The food and feeding habits of the species have been studied with reference to the different life stages such as juveniles, subadults and adults during the different phases of life based on stomach content analysis. The percentage of meat recovery and protein, carbohydrate and lipid content of meat have been described in the section dealing with proximate composition. In section three the distribution and abundance of the crab for the entire Indian EEZ and some contiguous ares have been described and illustrated in detail separately for pelagic and benthic realms. The size frequency disrtibution, sex ratios, length weight relationship and relative abundance of breeding population in the experimental catches have been dealt with in detail and discussed.

Artemia occurs in the natural salt lakes as well as in manmade salt pans. Efforts are being made to identify new natural habitats of brine shrimp, besides augmenting the production through extensive and intensive culture operations to meet the demands of the expanding aquaculture industries. Despite the availability of volumnous literature on Artemia in general, information on population biology and ecology of brine shrimp in natural environment, practicularly from India, is extremely poor. Hence the present study was designed to collect information on the population biology and ecology of Artemia from salinas of south east coast of India.

It is an established fact that the world population swells at an alarming rate year after year, and over half of the same is believed to suffer from malnutrition. At the present rate of population explosion it is likely that the global population may up from the present level of 5 billion to about 8 billion by the close of the present centuary (Becker, 1992). The food from land is so limited that it may not be able to satisfy even the basic requirement of the ever increasing population. One of the alternative to overcome this problem of food shortage is to tap the vast resources of the ocean which could nourish the human population many times more than its present level. According to FAO fishery Statistics the world fish production in 1990 amounted to about 97 million tonnes of which 95.8 million tonnes have come from the sea. Crustaceans comprising of prawns lobsters and crabs accounted for about 4.4% of this, which are the most highly valiJable commodities t:!{ virtue of their pivotal role in the seafood industry of the world. In India, the marine fiShery is mostly export oriented and among the seafood items exported from the country, the crustaceans account for 80ut 45 % in terms of volume and 75% in terms of value. According to the latest export figure, this amounts to about 14,000 million rupees annually (Sukumaran, 1992). Among edible crustaceans crats occupy the third rank, the first and second positions being given to prawns and lobsters on account of their demand in the overseas markets. Crab meat is considered as a delicacy in many parts of the world and within the country it is an important source of protein rich food for the less affluent society of coastal areas. .Besides its immense nutritive value, the crab meat also carries many therapeutic properties. Crab shells are rich source of chitin and its chitosan content which have numerous industrial and medicinal applications, particularly in the manufacture of artificial fabrics, printing inks, photographic emulsions adhesive cosmetics, dialysers and anticoagulants (Mendenhall, 1971, Muzzarelli and Pariser, 1978, Sambasivan, 1992). It is estimated that the world export earnings from chitin would be about 200 crores dollars by the end of 2000 AD (Girish Babu, 1990).

The findings of this present study forms the first report on the feeding ecology of the deep water shrimp, A.alcocki from the Arabian Sea. Gut content analysis revealed that the species consumes highly diversified diet and feeds largely on invertebrates, crustaceans (Amphipods, euphausiids), foraminiferans, molluscs from the benthic substrate and to a lesser extent on mesopelagic fishes having seasonal fluctuations. Females are found to be effective feeders (feeding intensity and fullness) in comparison with males. The results of the present study indicate the quantitative criteria for the determination of major prey taxa which in turn addresses the need for the development of spatial management plans in this species. Major factors that drive the seasonal variation in the feeding strategy of this species, due to the increased energy requirements related to the availability of food in the marine habitat, ontogenetic and sexual developments. The bigger size of the animal with good swimming capability helps in the selection of prey, while the smaller individuals depend on the epibenthic organisms for their food.

The findings of the present study, twenty-one deepsea caridean shrimp species were identified by conventional taxonomy during the study under seven families Pandalidae, Acanthephyridae, Oplophoridae, Crangonidae, Pasiphaeidae, Glyphocrangonidae, Hippolytidae and Stylodactylidae. Out of twenty one, thirteen species are new distributional records reported for the first time from the southern coast of India. The family with the highest number of species observed was Pandalidae (6), Crangonidae (4), Acanthephyridae (1), Pasiphaeidae (1) and Glyphocrangonidae (1). Accounting to molecular analysis a total of 121 sequences of COI and 16S was deposited in the GenBank database belonging to 8 genera under 5 families from the southern coast of Indian water. The truss morphometric analysis of H. chani confirms the presence of three distinct populations along the southern coasts of India. Based on reproductive biology of H. chani, A total of 1518 male individuals were measured from five landing centers along the southern coast of India ranging in total length from 7 to 13 cm, 1,206 non ovigerous females ranging from 6.4 to 14 cm and ovigerous females (633 specimens) ranging between 8.5 to 14 cm. The body weight in males ranged between 0.9 to 14.3 g, non ovigerous females 1.0 to 21.1 and ovigerous females are 3.4 to 26.6 g and fecundity estimation revealed the average absolute fecundity was 19041 eggs, which varied from 830 to 45650 in females (Stage 1) with the total length of 90 to 134 mm and carapace length in 20 to 36 mm of the specimen along the southern coast of India.

The penaeid and caridean prawns are the most sought after decapod crustaceans all over the world. This is because of their importance as an esteemed food of gourmet and economic significance. There is an ever increasing demand for prawn products in the international and national markets. At the same time it is realised that enhancing of their production from the coastal waters from where they are largely exploited a t present may not be possible due to the limited availability of stocks, heavy fishing pressure and increasing environmental hazards. This has led to frantic search for additional resources or methods of augmenting the production either through culture in suitable systems or exploitation of the resources in the under exploited andlor new grounds.

Nutrition is the process of providing nourishment to the living organism for its healthy upkeep, growth and reproduction. Nutrient substances for this purpose are provided by food. An individuals nutritional status is dependent on the provision of sufficient nutrient substances, and good utilization of these nutrients. Poor .status of nutrition may be caused by eating food that is inadequate in amount or kind or due to failure in assimilation and utilization of nutrients from the ingested food. The chief function of food is to supply nutrient material to meet the physiological needs of the organisms. such as to supply energy. to build and maintain the cells and tissues, and to regulate body processes. In general, there are two types of nutrients - energy nutrients (proteins, lipids, and carbohydrates) and non-energy nutrients (vitamins and minerals). Among the energy nutrients. carbohydrates and lipids form chief sources of energy, but protein, primarily, is utilized for growth. In formulated feeds both energy nutrients and non-energy nutrient. should be found in adequate levels and in balanced proportions.

The study regarding 'Studies on the use of probiotics in the larval rearing of the shrimp Penaeus monodon . was carried out by studying the effect of three probiOlic organisms. Saccharomyces boulardii. Lactobacillus plal1farulll and Bacillus sublilis. The parameters monitored were. level of enrichment in larvae and post larvae, survival. weight gain, effect on other bacterial flora and resistance to a pathogenic Vibrio harveyii infection. Attempts were made to find out the optimum enrichment duration and maximum enrichment levels of the above probiotic organisms in Arlemia nauplii and also the difference in enrichment level between two brands of Arlemia nauplii . The study \\as carried out in larval as well as in post larval stages. Direct additions of probiOlics were carried out in larval stages while Saccharomyces boulardii and Bacillus sublilis enriched Arlemia metanauplii \\ere fed to the larvae in post larval section. Anemia enrichment experiments revealed the maximum enrichment levels as 3410 for Saccharomyces boulardii. 2093 for Bacillus sublilis and 105 CFUllarva for Laclobacillus plantarum. Enrichment levels also varied between the t\\O brands. 3410 CFU/nauplii for OSI and 1120 CFU/nauplii for Red Dragon brand in the case of Saccharomyces boulardii. Significant increase in weight gain and survival rate were noticed in larvae as well as post larvae in the experiments conducted. Highest enrichment levels were noticed for mysis Ill. Maximum enrichment levels noticed were 1535 CFUllarva for Saccharomyces boulardii and 2133 CFUllarva for Bacillus subtilis in the larval stages from zoea to PL I. while in post larvae it was I CFUllarva for Saccharomyces boulardii and 66 CFUllarva for Bacillus sub/ilis. Laclobacills planlarum could not be detected during the enrichment study. Addition of Saccharomyces bOl/lardii as \\ell as Bacillus sub/ilis significantly reduced Vibrio counts during mysis stage as well as during post larval stages. Effect on sea water agar counts were not significant during larval stages while in post larvae sea water agar counts were decreased with the application of Saccharomyces boulardii and Bacillus subtilis. Enrichment of Lactobacillus plan/anlln did not produce any significant effect on other bacterial flora. Addition of Saccharomyces boulardii and Bacillus sublilis increased the resistance of larvae to pathogenic Vibrio hmwyii infection in larvae as \I ell as post larvae. About 103 CFU/ml Saccharomyces boulardii broth and 104 to 105 CFU/ml of Bacillus sublilis cells were necessary to surmount Vibrio han'eyii infection in PL. I. Post colonization studies after discontinuing the feeding resulted in 98% reduction in Saccharomyces boulardii counts and 13% reduction in Bacillus sublilis counts after five days from PL I. In post larvae Bac/lus sub/ilis showed only 7% reduction in five days from PL 21. Post larvae fed with live enriched nauplii performed better than those fed with dead enriched nauplii. for the parameters studied. From the above study it is evident that Saccharomyces boulardii and Bacilllls sub/lis can be used as effective probiotic species for shrimp larviculture while Laclobacillusplantarum is not a suitable species.

Metapenaeus dobsoni (Miers) is the most abundant species along the coast of Kerala. It is cultured extensively by adoption of traditional farming practices. The geographical location and water source determines the seasonal and annual environmental fluctuations the prawn farming systems experiences. The life cycle of the shrimp includes its migration to the coastal deeper waters for spawning and the immigration of larvae to the estuaries for growth. The survival of the species in such complex ecosystems is thus critical to its life cycle. The animal adapts itself to different environments through a physiological process known as osmoregulation. The present study on osmoregulation in the penaeid prawn Metapenaeus dobsoni was thus undertaken to understand the mechanism adopted by this species to survive in different environments. A number of experimental work have been conducted to understand the effect of salinity on the internal variations. However the effect of the complex environmental conditions as existent in nature on the osmotic variations in this species has not been dealt with in any of the earlier studies.

ndia ranks second ,only to United states in prawn production (Mohamed. 1973) and earns valuable foreign exchange from export of this crustacean to the tune of Rs.329.70 crores. which formed 85% of the total shipment. of marine products in the year 1984-85 (Anon., 1985). Increasingly expanding demands for prawns at enviable profits in overseas markets, coupled with concurrent technological advances, have enormously increased the exploitation of natural stocks in recent years and raised the possibility or even probability of over-fishing which may eventually leads to the total disaster of the fishery itselt. It emphasises enforce- ment of rational fishing to ensure a long-term sustainable yield. In order to monitor the impact of increasingly intensified commercial fishing, the stock positions of prawns have, therefore, been periodically reviewed (Chopra. 1943; Panikkar and Menon, 1956; Bh1machar. 1963; Banerjl, 1969; Jones. 1969; Mohamed, 1973; Silas etal.,1981). Since each species, that constitutes the fishery has its characteristic beha- viour. movements and habitat a long-tem fishing may have varying degree of impact on each one of them. This necessitates in-depth studies on individual species with regards to the resources available and exploited.

A detailed study on the primary, secondary and t e r t i a r y production in different culture systems along with the various ecological parameters is currently lacking. Therefore, inorder t o fill the above lacuna an a t t e m p t is made to investigate thoroughly the various ecological parameters, both abiotic and biotic, of perennial and seasonal culture fields and canals in between coconut plantations along Cochin area lying adjacent to Vembanad lake during different seasons of 1988 to 1990 period.

A major problem encountered by the aquaculturists is the availability of the right kind of food, especially the Iive food, for rearing the larvae and juveniles of the finfishes and shellfishes under controlled systems. Artemia, a phyllopodus small crustacean, popularly called as brine shrimp, have been used as an ideal food for finfishes and shellfishes throughout the world. They are being offered not only to the fishes, but also to other diversified groups of animals. It has been estimated that Artemia have been fed to more than 80 % of marine animals cultured so far, as a sole diet or in combination with other food sources (Kinne, 1977) The life cycle of Artemia is composed of different stages like cyst, nauplii, metanauplii and adult, and interestingly all these stages are excellent live foods. The freshly hatched nauplii of Artemia are the most extensively used form. It has been estimated that over 2000 metric tons of Artemia cysts are hatched annually and the nauplii are used as live food (Stappen, 1996). The Artemia cyst, which is the dormant form of egg, is also an excellent and convenient source of food for larval rearing The adult as well as pre-adult Artemia are also widely used as hlc foud fur shrimps, prawns and juvenile fishes. The role of , Artemia as live food in crustacean hatcheries is very substantial.

Nutrient interactions and interrelationships cannot be ignored in nutrition research. Among the macronutrient interaction mechanisms studied calorie protein interaction is the first to be taken up in any animal either terrestrial or aquatic. Shrimp is no exception in this regard. Thus research in crustacean nutrition began in the laboratories of Dr. Kanazawa and Dr. Provasoli in the 1960s in Japan (Kagoshima University) and United States (Yale University) respectively. Dr. Kanazawa focused on development of test diets by modifying his own diets designed for silkworm, to study the absolute macronutrient requirements in Penaeus japonicus. His effort was 'with a vision to support the commercially successful shrimp mariculture in Japan then. Dr. Provasoli, motivated by his success in defining the nutrient requirements in the culture media for freshwater and marine algae, extended his work to define the nutrient requirements of certain crustaceans like Artemia and Moina, which consumed algae. Some of the first descriptions of macronutrient and micronutrient interactions came from him.

Deep-water prawns Haliporoides triarthrus and langoustines Metanephrops mozambicus are endemic to the South West Indian Ocean (SWIO) region and make up the largest proportion of deep-water crustacean trawl catches in Mozambique and South Africa. Despite their economic importance to these fisheries, little is known about their distribution, biology and genetic population structure. The metapopulation genetic variation of H. triarthrus and M. mozambicus was assessed from 220 specimens per species collected from three sites in Mozambique (Bazaruto A, Boa Paz and Inhaca), two sites in western Madagascar (Morombe and Tulear) and one site in eastern South Africa (Durban). Two fragments of the mitochondrial region were amplified using universal primers ribosomal 16S subunit (16S) and mitochondrial cytochrome oxidase subunit I (COI). From H. triarthrus, fragments of 569 base pair (bp) (16S) and 1300 bp (COI) were amplified. A total of 207 sequences (16S) and 151 sequences (COI) were recovered, and 69 and 78 haplotypes identified, respectively. Metanephrops mozambicus 16S and COI genes produced similar fragment lengths, and 112 (16S) and 127 haplotypes (COI) were recovered. Both species demonstrated high genetic diversity and significant population differentiation in the SWIO region. Two sister-species (or subspecies) of H. triarthrus were identified, one occurring along the African continental shelf and the other off western Madagascar. Furthermore, individual populations making up each lineage were genetically structured, as indicated by the absence of shared haplotypes, and should be recognized as demographically distinct subspecies. Both species have undergone recent population expansions, likely since the late Pleistocene. The large anti-cyclonic and cyclonic eddies prevalent in the Mozambique Channel, and the boundary area between these eddies and upper Agulhas Current are likely factors driving larval retention or return process, thus giving rise to the observed genetically structured populations. The findings from this study are unique for the SWIO region, and may lead to a paradigm shift in the way that deep-water crustacean stocks are perceived by fisheries managers – instead of single shared stocks, they comprise of many isolated ones, in spite of the dispersal potential of larvae in strong ocean current regimes. Thus stocks should be managed as small independent units.
Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2013.

Deep-water trawling (>200 m deep) for crustaceans in the South West Indian Ocean (SWIO) yields catches of several species, including prawns (Haliporoides triarthrus, Aristaeomorpha foliacea, Aristeus antennatus and Aristeus virilis), langoustine (Metanephrops mozambicus), spiny lobster (Palinurus delagoae) and geryonid crab (Chaceon macphersoni). Infrequent deep-water trawling takes place off Tanzania, Kenya and Madagascar; however, well-established fisheries operate off Mozambique and South Africa. Regular trawling off South Africa started in the 1970’s, mainly targeting M .mozambicus and H. triarthrus. Catch and effort data for the South African fishery were regularly recorded in skipper logbooks over a 23 year period (1988 – 2010); this database was obtained from the Department of Agriculture, Forestry and Fisheries (DAFF) in order to assess abundance trends of M. mozambicus and H. triarthrus. Generalized linear models (GLM) were used to quantify the effects of year, month, depth and vessel on catch per unit effort (CPUE). By year, the standardized CPUE of M. mozambicus increased, and three factors (or a combination of them) could explain the trend: reduced effort saturation, improved gear and technology, or an increase in abundance. By month, CPUE peaked in July and was highest between depths of 300 and 399 m. The standardized CPUE of H. triarthrus fluctuated more by year than for M. mozambicus, possibly because it is a shorter-lived and faster growing species. The monthly CPUE peaked in March, and was highest between depths of 400 and 499 m. Totals of 2 033 M. mozambicus (1 041 males and 992 females) and 5 927 H. triarthrus (2 938 males and 2 989 females) were sampled at sea between December 2010 and March 2012, during quarterly trips on-board a fishing trawler. A GLM framework was used to explore their size composition, sex ratio variability, size at maturity and reproductive cycles. Male and female M. mozambicus size distributions were similar, but varied by month and decreased as depth increased. Female H. triarthrus were significant larger than males; size structure varied by month, but showed no change over depth. The sex ratio of M. mozambicus favoured males (1 : 0.89), but was close to parity in all months, except November when males predominated. H. triarthrus exhibited parity (1 : 1.002) with no significant variations in sex ratios by month. The proportion of egg-bearing M. mozambicus in the population declined between March and August (hatching period) and then increased until December (spawning period). The L₅₀ (length at 50% maturity) of M. mozambicus was estimated to be 49.4 mm carapace length (CL), and the smallest and largest observed egg-bearing females were 33.5 and 68.6 mm, respectively. No reproductively active female H. triarthrus were recorded during the sampling period. Growth parameter estimates for M. mozambicus (male and female combined) using Fabens method were K = 0.48 yearˉ¹ and L∞ = 76.4 mm CL. Estimates for the von Bertalanffy growth formula (VBGF) were: K = 0.45 yearˉ¹ and L∞ = 76.4 mm CL. H. triarthrus male and female growth parameter were estimated separately. For males they were K = 0.5 yearˉ¹ and L∞ = 46.6 mm CL using Fabens method, and K = 0.76 yearˉ¹ and L∞ = 46.6 mm CL using the VBGF. For females they were K = 0.3 yearˉ¹ and L∞ = 62.9 mm CL using Fabens method, and K = 0.47 yearˉ¹ and L∞ = 62.9 mm CL using the VBGF. CL to total weight regressions were calculated for both species; no significant differences were found between male and female M. mozambicus, although H. triarthrus females became larger and heavier than males. Comparisons with three earlier studies (Berry, 1969; Berry et al., 1975; Tomalin et al., 1997) revealed no major changes in the biology of either species off eastern South Africa. Stocks appear to be stable at current levels of fishing pressure, although some factors are not yet fully understood. Disturbance caused by continual trawling over a spatially limited fishing ground may affect distribution and abundance patterns, especially in M. mozambicus, which was less abundant in the depth range trawled most frequently. The absence of reproductive H. triarthrus in samples suggests that they occur elsewhere, and there is some evidence of a possible spawning migration northwards to Mozambique; this suggests that H. triarthrus is a shared stock between South Africa and Mozambique. The results from this thesis will add to the knowledge of M. mozambicus and H. triarthrus in the SWIO, and provide a basis for developing sustainable management strategies for the deep-water crustacean trawl fishery off eastern South Africa.
Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.