Made available in DSpace on 2015-04-17T14:55:35Z (GMT). No. of bitstreams: 1 parte1.pdf: 1790409 bytes, checksum: 2c9e9422fbfc1c76e73393d4b9808a5e (MD5) Previous issue date: 2010-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The research aimed to study the emic knowledge of swimming crabs (Portunidae - Callinectes spp.) fishermen, Tramataia community, located on the margins of Mamanguape River Estuary (MRE) from january 2009 to may 2010. The methodology encompassed qualitative methods: participant observation, free and semi-structured interviews and questionnaires. 30 community fishermen were interviewed. At least four captures techniques were identified: puçá e linha , trawl, siri de seco and siri de alagado . The swimming crabs are used for own consumption and marketing. According to the fishermen the capture techniques are determined by tide type. The sale of swimming crab meat is more usual in the region, but can also be marketed alive or frozen. Process stages of meat withdrawal consist: washing, cooking, meat removal, packaging, weighing and storage. The final product is marketed in the community, adjacent communities or free markets, and in some cases, by middlemen. Fishing in the community is characterized as artisanal and is performed both by women as men. The educational level of fishermen is low and the majority never completed elementary school. Because of the low profit of swimming crabs fishery, fishermen commonly exploit other resources. The results indicated that swimming crabs constitute an important basis of resource and survival for many families of Tramataia community, therefore this work can be useful to support future management plans to the region. / O foco desta pesquisa foi estudar o conhecimento êmico dos pescadores de siris (Portunidae - Callinectes spp.), da comunidade Tramataia localizada as margens do Estuário do Rio Mamanguape (ERM). A pesquisa desenvolveu-se de janeiro de 2009 a maio de 2010. A metodologia envolveu métodos qualitativos: observações participantes, questionários, entrevistas livres e semi-estruturadas. Foram entrevistados 30 pescadores da comunidade. Foram identificadas quatro técnicas de coleta: puçá e linha, rede de arrasto, siri de seco e siri de alagado. Os siris são utilizados para consumo e comercialização. A técnica de captura é determinada pelo tipo de maré. A venda da carne de siris é mais freqüente na região, mas os mesmos podem ser comercializados vivos ou congelados. O processo de beneficiamento da carne consiste de: lavagem; cozimento; retirada da carne; acondicionamento; pesagem e estocagem. O produto final da pesca é comercializado na comunidade, comunidades vizinhas ou feiras livres, e em alguns casos, para atravessadores fixos. A pesca na comunidade caracteriza-se como artesanal e é realizada tanto por mulheres como por homens. O nível de escolaridade dos pescadores é baixo, a maioria não chegou a completar o ensino fundamental. A margem de lucro com a comercialização dos siris é pequena, levando os pescadores a explotar outros recursos. Os resultados apontam que a atividade de pesca de siris constitui importante fonte de recurso e de sobrevivência para inúmeras famílias de pescadores de Tramataia, sendo assim esse trabalho pode subsidiar a elaboração de futuros planos de manejo na região.

Hypoxia or dissolved oxygen concentrations < 2 mg/L is a problem in estuaries worldwide. In Lake Pontchartrain, a 250 km2 de-faunated zone exists as a result of salinity stratification and episodic hypoxia. Mature common rangia clams (Rangia cuneata) are not found within this zone. Blue crabs (Callinectes sapidus) are important estuarine predators and may move in and out of the hypoxic zone to feed on hypoxia-stressed rangia clams. To test the effects of hypoxia on predation, rangia clams were exposed experimentally to severe hypoxic conditions (< 0.75 mg/l) for 72-hours and then presented to blue crabs. One hypoxic and one normoxic clam were added to each aquarium containing a blue crab for each trial, and crab feeding choices were observed and recorded. I found prey choice varied among crabs, but in general, the experimental data demonstrates that crabs chose to feed on hypoxia-stressed clams over clams kept under normoxic conditions.

<p>The dissertation work discussed here focuses on the behavioral and physiological aspects of visual sexual signaling in the blue crab, <italic>Callinectes sapidus</italic>. The blue crab has a pair of apposition compound eyes that are relatively acute (1.5 &deg; resolution) for an arthropod. The eyes have two photopigments sensitive to blue (&lambda;_max = 440 nm) and green (&lambda; _max=500 nm) light, allowing for simple color vision. Visual cues and signals are used during antagonistic and sexual communication and primarily involve claw-waving motions. A primary feature of the blue crab morphology is its sexually dimorphic claw coloration; males have blue and white claws and females have red claws. However, despite the potential for interesting color signaling, visual cues have typically been considered non-important, particularly in sexual communication where chemical cues have dominated blue crab signaling studies. </p><p>In a series of experiments designed to simultaneously test the role of visual cues in mating behavior and blue crab color vision, I tested males' responses to photographs of females with differently colored claws. I found that photographs of females elicited male courting behaviors. I also found that males preferred females with red claws over those with white or isoluminant (i.e. matched brightness) gray claws. The discrimination of red from isoluminant grey showed the use of color vision in male mate choice. </p><p>In natural populations, the claws of sexually mature females vary from light orange to deep red. To determine males' abilities discriminate between similar colors, I tested male color preferences for red against several shades of orange varying in brightness. Overall, males showed an innate preference for red-clawed females over those with variations of orange claws. However, in tests between red and orange shades similar in both brightness and hue, male blue crabs did not show a distinct preference, suggesting that males are either not able or not motivated to discriminate between these shades. Further, my results suggest that male blue crabs may use a mixture of chromatic and achromatic cues to discriminate between long-wavelength colors.</p><p>After confirming the use of color in mate choice, I focused on the role of claw color in intraspecific communication. To quantify claw coloration, I measured spectral reflectance of claws of a blue crab population in North Carolina. In both sexes, the color of the claw varied with reproductive maturity and may act as a cue of reproductive readiness. Additionally, there was individual variation in claw color which could indicate individual quality. I have modeled the appearance of claw coloration to the blue crab eye and found that these color differences are visible to the blue crab eye and potentially signal gender, reproductive readiness, and/or individual quality. </p><p>After investigating male mate choice, I began investigating visual aspects of female mating behavior. In the blue crab, like many crustaceans, courtship occurs during the female molting cycle and copulation takes place after the female has shed her exoskeleton. In crustaceans and other arthropods with compound eyes, the corneal lens of each facet is part of the exoskeleton and thus shed during molting. I used optomotor assays to evaluate the impact of molting on visual acuity (as measured by the minimum resolvable angle <italic> &alpha _min</italic>) in the female blue crab. I found that visual acuity decreases substantially in the days prior to molting and is gradually recovered after molting. Prior to molting,<italic> &alpha_min </italic>was 1.8 &deg;, a value approximating the best possible acuity in this species. In the 24 hours before molting, <italic> &alpha _min</italic>increased to a median of 15.0 &deg; (N=12), an eight-fold drop in visual acuity. Six days after molting, <italic> &alpha _min</italic>returned to the pre-molting value. Micrographs of <italic>C. sapidus </italic> eyes showed that a gap between the corneal lens and the crystalline cone appeared approximately five days prior to shedding and increased in width the process progressed. This separation was likely responsible for the loss of visual acuity observed in behavioral tests. Since mating is limited to the female's pubertal molt, a reduction in acuity during this time may have an effect on the sensory cues used in female mate choice. These results may be broadly applicable to all arthropods that molt and have particular importance for crustaceans that molt multiple times in their lifetime or have mating cycles paired with molting.</p> / Dissertation

Many species use color during courtship displays, with the more colorful individuals often selected as potential mates. Female blue crabs, Callinectes sapidus, display prominent red markings on their chelipeds, which is absent in males. I tested the hypothesis that females use this sexual dimorphism as an effective signal to potential mates. Body size was positively correlated with size of the colorful pattern on the crusher dactyl. Digital imaging techniques were used to examine and quantify a pattern of coloration in the female blue crab. Morphometric measurements were made using digital images of the carapace and chelae of crabs collected along the Gulf of Mexico coast in Galveston, Texas. Color complexity was examined on digital images of the chelae using Adobe? Photoshop? and Image J. Specific wavelengths were selected and their presence within the attribute quantified and evaluated. To determine whether male blue crabs prefer more colorful females, males were given a choice between females of different female coloration. Males displayed more often and directed more courtship displays towards the more colorful females. I hypothesize that male blue crabs use cheliped coloration as a visual cue for mate selection.

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves [52]-55).

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [39]-42).

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : 27-28).

Thesis (M.S.)--University of North Carolina at Wilmington, 2003.

Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 111-117)

The process wastewater from three blue crab processing plants in Virginia was characterized. Most of these effluent streams were highly concentrated. For example, the retort water from the cookers exhibited the following concentrations: BOD₅ = 14,000-29,000 mg/L, TSS = 650-6,200 mg/L, TKN-N = 2,500-4,000 mg/L, NH3-N = 70-160 mg/L and Total Phosphorus= 100-185 mg/L. One process effluent contained chloride concentrations exceeding 100,000 mg/L. Analysis of production and effluent characterization data from two mechanized plants revealed that wastewater volumes and concentrations varied significantly between the two plants. Both plants exhibited highly variable daily and seasonal production. Treatability studies were completed on the process wastewater because discharge limits exist for TSS, Oil and Grease and in some cases BODs and ammonia. Settling and filtration studies were performed on these effluents. The organics and nutrients in the wastes were highly soluble and limited reduction of COD (18-65% reduction), BOD₅ (9-49% reduction), TKN-N (9-62% reduction), and TP (10-66%) was achieved by filtration. Acidification of the concentrated effluents caused some coagulation of the contents. Coagulation by pH adjustment was most effective between pH 3.0-4.0. TSS removals of 76- 93%, and BOD5 removals of 6-30% were achieved by pH adjustment, thereby showing promise as a pretreatment method. Anaerobic biological treatment systems appear promising for the treatment of wastewater from blue crab processing plants (effluent BOD₅s ranged from 150-420 mg/L), especially for cooker effluent. However, there is concern that salt from the Harris Claw operation will decrease anaerobic treatment performance and that effluent NH3 and TSS levels will need to be further reduced to meet permit limits. Pretreatment of process wastewater by means of pH adjustment did not improve anaerobic treatability. / Master of Science