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Pedro E Saucedo - One of the best experts on this subject based on the ideXlab platform.
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Analysis of different methods to estimate fecundity in bivalve molluscs
Invertebrate Reproduction & Development, 2015Co-Authors: Jorge I. Cáceres-puig, Pedro E Saucedo, Jorge Chávez-villalba, Carlos Cáceres-martínezAbstract:AbstractWe analyzed the advantages and disadvantages of three methods to estimate potential fecundity in the bivalve molluscs Pinctada Mazatlanica and Atrina maura, both species having commercial value in northwestern Mexico. Data of gonad samples collected during the breeding season in March 1999 (P. Mazatlanica) and March 2003 (A. maura) were processed with histological techniques combined with Cavalieri’s Principle; stereological analysis of the gonad with the caliper method; and estimation of the theoretical radius of oocytes. These estimates were compared to a reference value obtained from direct counts of the number of oocytes stripped from the gonad. Compared to other methods, potential fecundity determined with the caliper method was more accurate in both species: A. maura (9.8–15 × 106 cells ind−1 and P. Mazatlanica (10.8–17 × 106 cells ind−1). The potential of the caliper method, combined with image analysis software may offer accurate estimates of aspects of reproduction in different bivalve sp...
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evaluation of natural and commercial probiotics for improving growth and survival of the pearl oyster Pinctada Mazatlanica during late hatchery and early field culturing
Journal of The World Aquaculture Society, 2010Co-Authors: Oscar L Aguilarmacias, Josafat J Ojedaramirez, Angel I Campacordova, Pedro E SaucedoAbstract:Survival and growth of pearl oyster, Pinctada Mazatlanica, juveniles fed microalgae supplemented with natural and commercial probiotics were measured for 21 d at the hatchery. Probiotics tested were (1) a Lactobacillus sp., (2) a mix of two bacilli, Burkholderia cepacia and Pseudomonas aeruginosa, (3) a marine yeast, Yarrowia lipolytica, (4) Epicin-hatchery® as commercial probiotic, (5) an antibiotic oxytetracycline, and (6) the control group fed Isochrysis galbana, Pavlova salina, and Chaetoceros muelleri only. When the hatchery phase ended, the effects of probiotics were followed during the early stages of field cultivation (90 d). Different from the control group, natural probiotics significantly improved performance of juveniles during both phases, particularly in the field. The treatment with Lactobacillus sp. significantly increased survival by 72%, growth in shell height by 63%, and growth in wet weight by 83% over the control. The marine yeast and mix of bacilli provided intermediate results, enhancing survival by 55–65%, shell height by 55–58%, and wet weight by 70–76% compared with the control. Conversely, growth and survival in the treatments with Epicin and oxytetracycline were significantly lower than in the control. These results show the potential of natural probiotics for improving hatchery rearing of this pearl oyster.
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interactive effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada Mazatlanica
Aquaculture Research, 2009Co-Authors: Pedro E Saucedo, Arely Martinezlopez, Jorge I CacerespuigAbstract:The combined effects of temperature and diet on the growth and biochemical composition of juveniles of the pearl oyster Pinctada Mazatlanica at the hatchery were investigated. Specimens were subjected to a combination of four temperatures (20, 23, 26 and 29 °C) and five microalgal diets (Isochrysis galbana alone, I. galbana+Pavlova salina, I. galbana+Chaetoceros muelleri, C. muelleri+P. salina and I. galbana+P. salina+C. muelleri). An increase in shell height occurred in a linear pattern, while wet weight gain fitted a power law. Temperature, more than diet, exerted a stronger influence on the growth and condition of the specimens. The combination of 29 °C with P. salina+C. muelleri led to the fastest growth in shell height, while the combination of 29 °C with I. galbana+C. muelleri led to the highest wet and dry weight biomass. In contrast, specimens grew significantly less in shell height and wet weight at 20 °C, regardless of the diet. At all temperatures, the monoalgal diet of I. galbana led to the slowest growth of specimens, but in turn favoured the highest levels of protein, carbohydrate and lipid reserves as a possible strategy to store more energy reserves under stressful events.
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evaluation of quality indices of the gonad and somatic tissues involved in reproduction of the pearl oyster Pinctada Mazatlanica with histochemistry and digital image analysis
Journal of Shellfish Research, 2009Co-Authors: Eliana Gomezrobles, Pedro E SaucedoAbstract:ABSTRACT We evaluated indicators of quality for female gonads (ovary and oocytes), male gonads (testis and seminal tubules), and selected somatic tissues (fiber packages in the adductor muscle and adenomeres in the digestive gland) that participate in reproduction of the pearl oyster Pinctada Mazatlanica. The goal was to identify timing of optimal broodstock condition for larval rearing practices. Tissue samples were collected seasonally and processed with a combination of histochemistry and digital image analysis to develop a gonad tissue index, a lipid index, and a glycogen index. Seasonal changes in these indicators were correlated with changes in water temperature and chlorophyll a in the water. P. Mazatlanica uses a combination of stored reserves and food supply (conservative vs. opportunistic strategy) to regulate reproduction, but the way energy is acquired and allocated varies between sexes. Female gonads contained higher lipid contents during spring. We suggest energy allocation from digestive gl...
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digital image analysis of lipid and protein histochemical markers for measuring oocyte development and quality in pearl oyster Pinctada Mazatlanica hanley 1856
2009Co-Authors: Eliana Gomezrobles, Carmen Rodriguezjaramillo, Pedro E SaucedoAbstract:Abstract We applied quantitative histochemical techniques and digital image analysis to study seasonal cycles of use of lipid and protein reserves during vitellogenesis in the pearl oyster Pinctada Mazatlanica. Female gonad samples were collected seasonally during an annual cycle and processed histologically to characterize the gametogenic cycle, analyze variations in the frequency and size of vitellogenic and postvitellogenic oocytes and calculate the ooplasm:nucleoplasm ratio for both types of oocytes. Lipid and protein inclusions in each type of oocyte were identified using Sudan Black B and Schiff's ninhydrin stains. In both cases, quantification of lipid and protein components was performed through measuring variations in the color coverage area of the oocyte with a digital image analysis system. With this procedure, we calculated a lipid index and a protein index to refer oocyte quality. The lipid index was higher in winter, suggesting a strategy towards storage in the gonad. The protein index was h...
Mario Monteforte - One of the best experts on this subject based on the ideXlab platform.
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factors influencing recruitment of hatchery reared pearl oyster Pinctada Mazatlanica hanley 1856 spat
Journal of Shellfish Research, 2005Co-Authors: Pedro E Saucedo, Horacio Berveraleon, Mario Monteforte, Paul C Southgate, Pablo MonsalvospencerAbstract:Abstract We evaluated experimental collection of Pinctada Mazatlanica spat on substrates of different textures and colors placed at different depths within settlement tanks. When larvae reached the pediveliger stage (day 25), black-colored spat collectors (“envelope” type) composed of the following materials were offered as settlement substrates: onion bag, mosquito net, fishing net, and 63% shade-cloth. Spat collectors measured 30 × 30 cm and were composed of an outer bag and inner substrate made of the same material. The influence of the color of spat collector material on recruitment was investigated using a second type of spat collector composed of onion bags as the outer bag and inner substrate (“bag” type). Bags were prepared in 3 different outer/inner (O/I) color combinations of green/green, green/black, and red/black (O/I). Both types of collectors were deployed at different depths within settlement tanks. Approximately 2.7% of the initial larval population survived, resulting in 35,583 spat. Of t...
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effect of temperature on oxygen consumption and ammonia excretion in the calafia mother of pearl oyster Pinctada Mazatlanica hanley 1856
Aquaculture, 2004Co-Authors: Pedro E Saucedo, Mario Monteforte, Lucia Ocampo, Horacio BerveraAbstract:Abstract The effect of temperature on oxygen consumption and ammonia excretion in the pearl oyster Pinctada Mazatlanica was studied as a strategy to define the optimum thermal range for experiments on reproductive conditioning of broodstock of this species. Oysters were taken to the laboratory, acclimated for 2 weeks at four temperatures (18, 23, 28, and 33 °C), and transferred to respiration chambers for individual measurements of oxygen consumption and ammonia excretion at the same temperatures. Respiration and excretion rates, as well as routine respiratory/excreted energy and Q 10 coefficients were calculated. One-way ANOVA was applied to determine differences in these parameters as a function of temperature. All physiological parameters yielded highly significant differences with increasing temperature, suggesting that an adequate metabolic temperature range for the species may lie between 23 and 28 °C. Within this range, a combination of active respiration and low ammonia excretion, together with Q 10 coefficients near 2, suggest the existence of compensatory mechanisms that allow the species to perform seasonal regulation during moderately warm temperature changes. In contrast, 18 and 33 °C represented marginal temperature conditions close to the tolerance limits of the species. In particular, 33 °C was a stressful temperature for P. Mazatlanica because of high ammonia excretion. More studies under conditions of satiation and hypoxia, as well as experiments testing lower and higher lethal temperatures are needed to understand the energy budget of the species.
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evidence for male biased effective sex ratio and recent step by step colonization in the bivalve Pinctada Mazatlanica
Journal of Evolutionary Biology, 2003Co-Authors: Sophie Arnaudhaond, Mario Monteforte, F Blanc, François BonhommeAbstract:This paper presents a comparison of the geographical distribution of genetic variability at mitochondrial and nuclear loci among pearl oyster populations from the tropical American Pacific coast (Pinctada Mazatlanica). Surprisingly, both mitochondrial and nuclear gene variability decreased regularly from north to south of the studied area, which, altogether with a significant correlation between genetic and geographical distances for mtDNA, suggests a recent colonization or re-colonization of the southern areas. However, the loss of diversity between north and south was much more important for mitochondrial than for nuclear DNA, and this did not translate into measurable fixation index at nuclear loci ( ^ ¼ 0.03, n.s.), contrary to the mitochondrial data ( ^ ¼ 0.18*). Smaller effective size of mtDNA accentuated by a strong male-biased effective sex ratio and step-by-step colonization from northern areas can explain this discrepancy among natural populations of this protandric species.
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gonadic conditioning of the calafia mother of pearl oyster Pinctada Mazatlanica hanley 1856 under two temperature regimes
Aquaculture, 2001Co-Authors: Pedro E Saucedo, Pablo Monsalvospencer, Humberto Villarreal, Carmen Rodriguezjaramillo, Cynthia Aldanaaviles, Teodoro Reynosogranados, Mario MonteforteAbstract:Abstract Gonadic conditioning of pearl oyster Pinctada Mazatlanica was studied under two water temperature regimes using cultured specimens. Before starting conditioning, specimens were induced to spawn with thermal shock. Two different regimes were evaluated, controlled temperatures (CT) and gradually increasing temperatures (IT). In both trials, specimens were fed daily with Isochrysis galbana and Chaetoceros gracilis in a proportion of 7:3. Gonad and muscle samples were excised from the oysters every 15 days and processed for histological analysis. Condition Index and Muscle Condition Index were calculated. Similarly, oocyte frequency and oocyte diameter measurements were made. ANOVA analyses were used to test significant differences in the frequency and diameter of postvitellogenic oocytes, and values of both condition indexes between temperature regimes, and over time. The IT showed more suitable conditions for gonad conditioning than CT, although the time needed for reaching maturity was higher in the former regime. For CT, a temperature of 24°C was the best for conditioning, since there were no traces of atretic oocytes, partially spawned specimens, and there were less previtellogenic oocytes and more postvitellogenic oocytes filling the follicles. At 20°C, no positive results were noticed. Condition indexes appear to be reliable indicators of gonad activity during conditioning in both trials. The ANOVA analysis detected significant differences in almost all the statistical treatments run for oocyte frequency, oocyte diameter and condition indexes according to temperature regime and over time.
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differential gonadal development of grafted and ungrafted specimens of the calafia mother of pearl oyster Pinctada Mazatlanica bivalvia pteriidae
Invertebrate Reproduction & Development, 2001Co-Authors: Pedro E Saucedo, Ilie S Racotta, Horacio Bervera, Humberto Villarreal, Mario MonteforteAbstract:Summary The present work deals with the existence of differential gonadal development between grafted and ungrafted specimens of the pearl oyster, Pinctada Mazatlanica. Oysters were collected as spat and extensively cultured until they were suitable for pearl formation. A mantle allograft was placed within the gonadal tissue and the treated oysters were maintained under the same culture conditions as untreated oysters. After a year of Keshi pearl formation, samples of gonadal tissue, digestive gland, and muscle were excised from each oyster and used for histological and biochemical analyses. The histological examination of gonads was supported with measurements of the oocyte frequency and diameter and the use gonadic and muscle performance indices. For biochemical analyses, the concentration of carbohydrates, proteins, lipids, and triacylglycerides was studied. A two-way ANOVA was applied for differences in the oocyte diameter, index values, and biochemical composition of specimens over time and experimen...
M Monteforte - One of the best experts on this subject based on the ideXlab platform.
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Episodes of environmental history in the gulf of California: Fisheries, commerce, and aquaculture of nacre and pearls
A Land Between Waters: Environmental Histories of Modern Mexico, 2012Co-Authors: M Monteforte, M. CarinoAbstract:Pearl oysters (Pinctada Mazatlanica and Pteria sterna) have played a fundamental role in the environmental history of the Gulf of California region for nearly five hundred years.1 Pearls' value derived from geographic and temporal coincidences in which ancient myths and legends that linked pearls to great wealth became enmeshed with changing human interactions with natural ecosystems. Christopher Columbus's accidental arrival in the Americas was the first step in opening the Gulf of California to European eyes, and with it the natural pearl oyster beds that soon became famous for the quality of their nacre and pearls. This discovery laid the foundations for what we call the "Pearl Myth," which drove the exploration of the Gulf and colonial settlement of the Baja California peninsula. The Pearl Myth was tinged with abstract, fairytale-like symbolism that derived from ancient European chivalry novels but was the guiding economic principle and political basis for the colonization of Baja California in the eighteenth century. The market for the Gulf's nacre (sometimes misidentified as "mother of pearl") and pearls emerged in the 1730s and led to the foundation of La Paz, which has been recognized as a major pearling center ever since. The Pearl Myth was grounded in commerce. For centuries, nobles and magnates collected jewelry and luxury items generously inlaid with nacre and pearls. The world's greatest personal fortunes and national treasures nearly always included such objects, many of which are now prominently displayed in museums, churches, and personal collections. Artisans and factories acquired great quantities of shells used to inlay fine objects with nacre decorations. Their handiwork can be seen throughout the world, in ceilings, doors, columns, and altars of temples and churches; in thrones and furniture adorning palaces and castles; in coffers and boxes of all shapes and sizes; in the formerly enormous button-making industry; in nacre decorations on firearms and other hand weapons; in pins, brooches, combs, hairbrushes, cufflinks, necktie sets, and other adornments and accessories for gentlemen; and in the huge quantity of jewelry with nacre and pearls that adorned royalty, celebrities, and countless women through the ages. The economic flows generated by pearl oysters prompted settlement in many isolated regions, but that did not keep traders from devastating wild populations in a race to meet global demand. The productivity of famous pearling regions gradually declined to near extinction in places such as the Red Sea, the Gulf of Manaar, the Seas of Timor and Arafura, northwestern Australia, South and Southeast Asia, the Philippines, South Pacific islands and atolls, the coasts and islands of the Antilles, and the Gulf of Panama. The Gulf of California was the last region to experience exhaustion, even though it was a major world supplier. The introduction of modernized diving suits in 1874 intensified the activity but did not extinguish the natural beds as in other regions, because farming activities in the Bay of La Paz in the early 1900s helped to support the natural repopulation of wild stocks. The Compañía Criadora de Concha y Perla de Baja California (Baja California Pearl and Shell Breeding Company, or CCCP) was the world's first successful experiment in massive cultivation of pearl oysters (P. Mazatlanica in this case) and allowed its founder, Gastón J. Vives, to build a uniquely successful business. The CCCP used a method of extensive aquaculture to cultivate pearl oysters.3 The main product was the excellent nacre of P. Mazatlanica destined for the European market; pearls were a natural and welcome byproduct of the process, and they appeared in greater numbers and quality on the natural oyster beds. Vives marketed hundreds of beautiful pearls in New York, London, Paris, and Venice before local rivalries and the violence of the Mexican Revolution ultimately led to the looting and destruction of the company's installations in 1914. Even so, the CCCP had left a mark on regional socioeconomic structure, and its closure severely restricted em - ployment and other economic activities associated with pearl oyster farming. Moreover, the end of continuous larvae supply and recruitment from reproduction of the millions of farmed pearl oysters had significant repercussions for the regional ecosystem-a blow made all the more severe when the new revolutionary government lifted previous restrictions on the fish - eries. Less than fifteen years later, the wild stocks had become severely exhausted. The environmental history of pearling in the Gulf of California follows a familiar global pattern. At different historical moments, with different trajectories, and each in a particular social context, the pearl fishery has experienced severe impoverishment. Nearly everywhere, the pearl industry garnered incredible Prof.ts for a few wealthy individuals at the expense of the health and welfare of thousands of divers. Later, after a few pioneering efforts at extensive aquaculture,4 pearl oyster farms succeeded in culturing pearls themselves (rather than the entire oyster, as Vives had) in Japan, Australia, India, and the Tuamotu atolls as these countries enforced bans and other protections for natural populations. Cultivated nacre and pearls have supplied the global market ever since the late 1950s, except for northwestern Australia, where pearl culture relies on the extraction of wild adults of the species P. maxima (the giant member of the Pteriidae, which can grow up to thirty centimeters in diameter). However, the Australian government and pearl industry manage this resource under strict rules and impose draconian sanctions on offenders. In 1952, Kokichi Mikimoto patented the special instruments that are used in the surgical induction to produce free round pearls, and he quickly became rich by cultivating the Japanese P. martensii on his farms. His intelligence and gift for self-promotion, along with enviable business acumen, allowed him to reach agreements with Australia and French Polynesia. Before long, Japanese technicians were in charge of pearl production throughout the world. The shift from natural to cultured pearls provoked long and ferocious debates among naturalists, jewelers, consumers, and even the public.5 Whatever the relative merits of arguments on both sides, overexploitation of natural beds had produced such severe shortages by the early 1900s that entrepreneurs and local governments had already begun to urge scientists to develop aquaculture technology. By the early 1960s, many producers had succeeded in developing their own techniques independent of Japanese control, and most pearl farms replaced divers (who worked in dangerous conditions for little pay) with skilled workers whose specialized knowledge commanded substantially better compensation. Today, the billion-dollar market for nacre and pearls has acquired a new shape. There are up to 1,500 farms of large pearl oysters (P. maxima and P. margaritifera) that produce forty tons of luxury pearls (aka "South Seas pearls") annually and 3,100 farms of P. martensi concentrated in Japan producing about twenty-four tons of the smaller pearl known as Akoya.6 The remarkable development of science and modern technology, as well as easy access to specialized expertise, ensures the feasibility of virtually every pearling venture. Management strategy is broadly similar on all farms, al - though each one has its peculiar characteristics owing to geography, environmental conditions, the bioecology of target species, idiosyncratic operational issues and management styles, and the local availability of equipment and materials. As an example of how a natural resource was transformed from food and simple ornamentation for native peoples into a global commodity initially harvested in the wild and later farmed artificially, the pearl industry is one of the most important episodes in the environmental history of the Gulf of California. The natural vocation of Pinctada Mazatlanica and Pteria sterna (that is, their capacity to produce nacre and pearls, and their positive response to aquaculture) influenced socioeconomic structures, cultural practices, and political and group dynamics in the region. In the ongoing search for sustainable development alternatives for renewable re sources, the environmental history of nacre and pearls serves as an important object lesson. © 2012 The Arizona Board of Regents. All rights reserved.
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Population structure and genetic variability of pearl oyster Pinctada Mazatlanica along Pacific coasts from Mexico to Panama
Conservation Genetics, 2001Co-Authors: Sophie Arnaud, François Bonhomme, M Monteforte, Nicolas Galtier, De DauradeAbstract:Populations of the Calafia pearl oyster Pinctada Mazatlanica of the American Pacific coasts have been considered endangered because of overfishing and/or alteration to coastal areas.We assessed genetic variability and the pattern of population structure among 9 samples collected from Mexico to Panama, using mtDNA RFLP analysis of two genes: 12S rRNA and subunit one of Cytochrome oxydase (COI). Haplotype diversity varied from 0.000 to 0.856. The Panama population appeared to be monomorphic, while the other samples exhibited a level of haplotypic variability similar to those reported in the literature for the same kind of analysis on other bivalves species. A test for the impact of demographic history on genetic diversity was applied on the sequence data, and the results were congruent with a recent decline of population sizes. Genetic differentiation was shown to follow a scheme of isolation by distance, with low levels of differentiation at the scales of ten to one hundred kilometres, whereas stronger and significant genetic structure was detected at a larger scale. Three significantly distinct groups could then be defined, which correspond to Northern Mexico, Southern Mexico, and Panama
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in situ growth of pearl oysters Pinctada Mazatlanica hanley 1856 and pteria sterna gould 1851 under repopulation conditions at bahia de la paz baja california sur mexico
Aquaculture Research, 1997Co-Authors: P Saucedo, M MonteforteAbstract:Pearl oysters Pinctada Mazatlanica (Hanley 1856) and Pteria sterna (Gould 1851) were studied for an annual cycle of in situ growth from May 1992 to April 1993. Organisms generated from extensive culture were kept under repopulation conditions at Caleta El Merito. Growth measurements of shell height and length were taken monthly. Data were used to build the annual growth curve of both species, to test the temporal relationship between shell height and length, to calculate monthly and total growth rate, to follow the modal progression with the ELEFAN software, and to fit the growth curve to the Von Bertalanffy equation. Growth dimensions increased steadily during the annual cycle, from 7 to 18 months old for P. Mazatlanica and from 11 to 22 months for P. sterna. No significant differences were detected between shell height and length during growth, although length seemed to grow faster. The ELEFAN program identified two modes in P. Mazatlanica (Rn= 0.205) and a single one for P. sterna (Rn= 0.557). A positive correlation to the Von Bertalanffy equation was seen for both species (r2= 0.97 for both species).
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Exploration and evaluation of natural stocks of pearl oysters Pinctada Mazatlanica and Pteria sterna (Bivalvia: Pteriidae): La Bay, South Baja California, Mexico
Ambio. Stockholm, 1992Co-Authors: M Monteforte, M. CarinoAbstract:Applied biological and ecological studies on the extensive culture of pearl oysters Pinctada Mazatlanica and Pteria sterna , are being developed in La Paz Bay, South Baja California, Mexico. Exploration in several sites and a preliminary evaluation of the natural stock was carried out in older to establish the localization and actual state of pearl-oyster populations. The 4 most dense populations of P. Mazatlanica were compared in terms of their densities and their size structure. It is evident that the actual pearl-oyster banks are scattered along the coast of the bay, they have low densities, and natural recruitment also seems to be low. Illegal and uncontrolled extraction of large and medium-sized individuals affect the natural recuperation of the resource negatively as well as the size structure of local populations. The areas commonly visited by tourists and fishermen show discontinuities in size distribution and an absence of large individuals. The results of the present study will be directly applied to choice of sites for seed captation and extensive culture.
M. Carino - One of the best experts on this subject based on the ideXlab platform.
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Episodes of environmental history in the gulf of California: Fisheries, commerce, and aquaculture of nacre and pearls
A Land Between Waters: Environmental Histories of Modern Mexico, 2012Co-Authors: M Monteforte, M. CarinoAbstract:Pearl oysters (Pinctada Mazatlanica and Pteria sterna) have played a fundamental role in the environmental history of the Gulf of California region for nearly five hundred years.1 Pearls' value derived from geographic and temporal coincidences in which ancient myths and legends that linked pearls to great wealth became enmeshed with changing human interactions with natural ecosystems. Christopher Columbus's accidental arrival in the Americas was the first step in opening the Gulf of California to European eyes, and with it the natural pearl oyster beds that soon became famous for the quality of their nacre and pearls. This discovery laid the foundations for what we call the "Pearl Myth," which drove the exploration of the Gulf and colonial settlement of the Baja California peninsula. The Pearl Myth was tinged with abstract, fairytale-like symbolism that derived from ancient European chivalry novels but was the guiding economic principle and political basis for the colonization of Baja California in the eighteenth century. The market for the Gulf's nacre (sometimes misidentified as "mother of pearl") and pearls emerged in the 1730s and led to the foundation of La Paz, which has been recognized as a major pearling center ever since. The Pearl Myth was grounded in commerce. For centuries, nobles and magnates collected jewelry and luxury items generously inlaid with nacre and pearls. The world's greatest personal fortunes and national treasures nearly always included such objects, many of which are now prominently displayed in museums, churches, and personal collections. Artisans and factories acquired great quantities of shells used to inlay fine objects with nacre decorations. Their handiwork can be seen throughout the world, in ceilings, doors, columns, and altars of temples and churches; in thrones and furniture adorning palaces and castles; in coffers and boxes of all shapes and sizes; in the formerly enormous button-making industry; in nacre decorations on firearms and other hand weapons; in pins, brooches, combs, hairbrushes, cufflinks, necktie sets, and other adornments and accessories for gentlemen; and in the huge quantity of jewelry with nacre and pearls that adorned royalty, celebrities, and countless women through the ages. The economic flows generated by pearl oysters prompted settlement in many isolated regions, but that did not keep traders from devastating wild populations in a race to meet global demand. The productivity of famous pearling regions gradually declined to near extinction in places such as the Red Sea, the Gulf of Manaar, the Seas of Timor and Arafura, northwestern Australia, South and Southeast Asia, the Philippines, South Pacific islands and atolls, the coasts and islands of the Antilles, and the Gulf of Panama. The Gulf of California was the last region to experience exhaustion, even though it was a major world supplier. The introduction of modernized diving suits in 1874 intensified the activity but did not extinguish the natural beds as in other regions, because farming activities in the Bay of La Paz in the early 1900s helped to support the natural repopulation of wild stocks. The Compañía Criadora de Concha y Perla de Baja California (Baja California Pearl and Shell Breeding Company, or CCCP) was the world's first successful experiment in massive cultivation of pearl oysters (P. Mazatlanica in this case) and allowed its founder, Gastón J. Vives, to build a uniquely successful business. The CCCP used a method of extensive aquaculture to cultivate pearl oysters.3 The main product was the excellent nacre of P. Mazatlanica destined for the European market; pearls were a natural and welcome byproduct of the process, and they appeared in greater numbers and quality on the natural oyster beds. Vives marketed hundreds of beautiful pearls in New York, London, Paris, and Venice before local rivalries and the violence of the Mexican Revolution ultimately led to the looting and destruction of the company's installations in 1914. Even so, the CCCP had left a mark on regional socioeconomic structure, and its closure severely restricted em - ployment and other economic activities associated with pearl oyster farming. Moreover, the end of continuous larvae supply and recruitment from reproduction of the millions of farmed pearl oysters had significant repercussions for the regional ecosystem-a blow made all the more severe when the new revolutionary government lifted previous restrictions on the fish - eries. Less than fifteen years later, the wild stocks had become severely exhausted. The environmental history of pearling in the Gulf of California follows a familiar global pattern. At different historical moments, with different trajectories, and each in a particular social context, the pearl fishery has experienced severe impoverishment. Nearly everywhere, the pearl industry garnered incredible Prof.ts for a few wealthy individuals at the expense of the health and welfare of thousands of divers. Later, after a few pioneering efforts at extensive aquaculture,4 pearl oyster farms succeeded in culturing pearls themselves (rather than the entire oyster, as Vives had) in Japan, Australia, India, and the Tuamotu atolls as these countries enforced bans and other protections for natural populations. Cultivated nacre and pearls have supplied the global market ever since the late 1950s, except for northwestern Australia, where pearl culture relies on the extraction of wild adults of the species P. maxima (the giant member of the Pteriidae, which can grow up to thirty centimeters in diameter). However, the Australian government and pearl industry manage this resource under strict rules and impose draconian sanctions on offenders. In 1952, Kokichi Mikimoto patented the special instruments that are used in the surgical induction to produce free round pearls, and he quickly became rich by cultivating the Japanese P. martensii on his farms. His intelligence and gift for self-promotion, along with enviable business acumen, allowed him to reach agreements with Australia and French Polynesia. Before long, Japanese technicians were in charge of pearl production throughout the world. The shift from natural to cultured pearls provoked long and ferocious debates among naturalists, jewelers, consumers, and even the public.5 Whatever the relative merits of arguments on both sides, overexploitation of natural beds had produced such severe shortages by the early 1900s that entrepreneurs and local governments had already begun to urge scientists to develop aquaculture technology. By the early 1960s, many producers had succeeded in developing their own techniques independent of Japanese control, and most pearl farms replaced divers (who worked in dangerous conditions for little pay) with skilled workers whose specialized knowledge commanded substantially better compensation. Today, the billion-dollar market for nacre and pearls has acquired a new shape. There are up to 1,500 farms of large pearl oysters (P. maxima and P. margaritifera) that produce forty tons of luxury pearls (aka "South Seas pearls") annually and 3,100 farms of P. martensi concentrated in Japan producing about twenty-four tons of the smaller pearl known as Akoya.6 The remarkable development of science and modern technology, as well as easy access to specialized expertise, ensures the feasibility of virtually every pearling venture. Management strategy is broadly similar on all farms, al - though each one has its peculiar characteristics owing to geography, environmental conditions, the bioecology of target species, idiosyncratic operational issues and management styles, and the local availability of equipment and materials. As an example of how a natural resource was transformed from food and simple ornamentation for native peoples into a global commodity initially harvested in the wild and later farmed artificially, the pearl industry is one of the most important episodes in the environmental history of the Gulf of California. The natural vocation of Pinctada Mazatlanica and Pteria sterna (that is, their capacity to produce nacre and pearls, and their positive response to aquaculture) influenced socioeconomic structures, cultural practices, and political and group dynamics in the region. In the ongoing search for sustainable development alternatives for renewable re sources, the environmental history of nacre and pearls serves as an important object lesson. © 2012 The Arizona Board of Regents. All rights reserved.
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Exploration and evaluation of natural stocks of pearl oysters Pinctada Mazatlanica and Pteria sterna (Bivalvia: Pteriidae): La Bay, South Baja California, Mexico
Ambio. Stockholm, 1992Co-Authors: M Monteforte, M. CarinoAbstract:Applied biological and ecological studies on the extensive culture of pearl oysters Pinctada Mazatlanica and Pteria sterna , are being developed in La Paz Bay, South Baja California, Mexico. Exploration in several sites and a preliminary evaluation of the natural stock was carried out in older to establish the localization and actual state of pearl-oyster populations. The 4 most dense populations of P. Mazatlanica were compared in terms of their densities and their size structure. It is evident that the actual pearl-oyster banks are scattered along the coast of the bay, they have low densities, and natural recruitment also seems to be low. Illegal and uncontrolled extraction of large and medium-sized individuals affect the natural recuperation of the resource negatively as well as the size structure of local populations. The areas commonly visited by tourists and fishermen show discontinuities in size distribution and an absence of large individuals. The results of the present study will be directly applied to choice of sites for seed captation and extensive culture.
Alejandra Garcia-gasca - One of the best experts on this subject based on the ideXlab platform.
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Spat collection studies on pearl oysters Pinctada Mazatlanica and Pteria sterna (Bivalvia, Pteriidae) in Bahia de La Paz, South Baja California, Mexico
Hydrobiologia, 1994Co-Authors: Mario Monteforte, Alejandra Garcia-gascaAbstract:The present work deals with the temporal and bathymetrical variations of the epifaunal community associated with two species of pearl oysters ( Pinctada Mazatlanica and Pteria sterna ) during a seed collecting season from June to November 1989. A total of 63 items (species, genera and/or families) were recorded; their variations in presence and abundance were followed during three periods (June–July, August–September and October–November). The collectors were examined for different immersion times (2, 4, 6 and 8 weeks) for each period. Community structure was compared through the Brillouin Index, the Morisita Index and the Importance Value. We define the chronology of spatfall for both species of pearl oysters and their bathymetrical distribution. Relationships between these species and the epifaunal community present into the collectors were analysed, searching for possible noxious effects on the survival of juvenile pearl oysters, and identifying index species related with their spatfall. A strategy for starting massive seed collection of both species is established, particularly for P. Mazatlanica .