A dinâmica populacional de Scomber japonicus peruanus (cavalinha) foi estudada com base nos dados de captura da pesca comercial obtidos mensalmente, de janeiro de 1990 a dezembro de 2003, no litoral peruano (3°23’S-18°20’S e 72°W-84°W), dentro do projeto “Seguimento de los recursos pelágicos en el litoral peruano” que vem sendo desenvolvido no Instituto del Mar del Perú – IMARPE. Nesse período, a Temperatura Superficial do Mar foi obtida mensalmente em cada uma das áreas de coleta. A análise dos parâmetros de crescimento e as taxas de mortalidade, bem como o padrão de recrutamento da cavalinha, foram feitos a partir dos dados da pesca comercial correspondente aos anos de 1996 a 2003, enquanto na avaliação do estoque utilizaram-se os do período de 1993 a 2003. A Temperatura Superficial do Mar variou de 13,60°C (2001) a 29,34°C (1998), sendo os valores mínimos encontrados em 1996 e 1999-2001 e máximos em 1992-1993 e 1997-1998. Os desembarques da espécie Scomber japonicus peruanus entre 1990 e 2003 variaram de 8.119 t a 387.659 t, sendo o valor médio 122.513 t. As médias dos desembarques mensais oscilaram entre 3.274 t e 16.853 t, com maiores valores registrados nos meses de novembro e dezembro de 1998, bem como em janeiro e março de 1999. As anomalias positivas máximas dos desembarques, que variaram de 134.985 t a 345.137 t, foram obtidas no período de 1997-1999 e em 2001, enquanto elevadas anomalias negativas nos anos de 1992 (-34.402 t) e 1993 (-32.894 t). Os resultados mostraram que no período de 1993-2003 o comprimento médio furcal da cavalinha diminuiu de 30,50 cm para 26,70 cm, que o comprimento furcal de primeira captura (Cf50) foi 26,40 cm e que o recrutamento ocorreu o ano todo, principalmente, no verão. xiii No período compreendido entre 1996 e 2003, o estudo do crescimento e mortalidade da cavalinha evidenciou que os valores do comprimento assintótico (Cf∞) e os da taxa de crescimento (K), obtidos pelo ELEFAN I e os registrados pelo método de Ford- Walford, foram 42,40 cm e 0,40 ano–1, respectivamente. O comprimento igual a zero (to) foi –0,37 ano–1 e a amplitude de oscilação (C) 0,40, enquanto os valores de Winter Point (Wp) 0,60 e o do índice de performance (φ) 2,86. A taxa média de mortalidade total (Z) obtida pela análise da curva de captura linearizada e pelo método de Beverton & Holt, foi 2,30 ano–1; a taxa de mortalidade por pesca (F) 1,97 ano–1 e a taxa de explotação 0,86 ano–1. A taxa anual de mortalidade natural (M) estimada pelo método de Rikhter & Efanov e pela equação de Pauly foi 0,50 ano–1. A longevidade da cavalinha foi 7,60 anos. A análise de coorte de comprimento e a aplicação dos modelos de rendimento por recruta de Beverton & Holt e o preditivo de Thompson & Bell, revelaram que o estoque de Scomber japonicus peruanus encontra-se sobre-explotado e próximo da capacidade máxima. / The population dynamics of the Scomber japonicus peruanus (Chub mackerel) was studied based on commercial fishing data obtained monthly from January 1999 to December 2003 off the Peru coast (3°23’S-18°20’S e 72°W-84°W), within the “Tracking of pelagic resources off the Peru coast” project which is being carried out at the Instituto del Mar del Peru – IMARPE. During this period, Sea Surface Temperature data was obtained monthly I n each one of the sampling areas. The analysis of the growth parameters, mortality rates, as well as the recruitment pattern of the Chub mackerel was obtained from commercial fishing data from 1996 to 2003. For stock assessment the time range was from 1993 to 2003. Sea Surface Temperature varied from 13.60°C (2001) to 29.34°C (1998) with minimum values being found in 1996 and 1999-2001 and maximum values in 1992-1993 and 1997-1998. The landing of the Scomber japonicus peruanus species between 1990 and 2003 varied from 8.119 t to 387.659 t, with an average of 122.513 t. The average of the monthly landings varied between 3.274 t and 16.853 t, with higher values registered on November and December 1998 as well as January and March 1999. The maximum positive anomalies of the landings, which varied from 134.985 to 345.137 t, were obtained in 1997 -1999 and in 2001. On the other hand, high negative anomalies were obtained in 1992 (-34.402 t) and 1993 (-32.894 t). The results show that from 1993 to 2003 the mean fork length of the Chub mackerel decreased from 30,50 cm to 26,70 cm, the fork length of the first catch (Cf50) was 26,40 and that recruitment occurred all year, especially during the summer. Between 1996 and 2003, the growth and mortality study of the Chub mackerel showed that the asymptotic body length (Cf∞) and the growth rate values (K) obtained by ELEFAN I and the ones xv registered by the Ford-Walford method were 42.40 cm and 0.40 cm year–1, respectively. The t-zero (length is 0) was –0.37 year–1 and the amplitude (C) 0.40. The Winter Point (Wp) value was 0.60 and the performance index (φ) 2.86. The mean total mortality rate (Z), obtained by analyzing the linearized catch curve and by the Beverton and Holt method, was 2.30 year–1. The rate of fishing mortality (F) was 1.97 year–1 and the exploitation rate 0.86 year–1. The annual rate of natural mortality (M) estimated by the Rikter and Efanov method and by the Pauly equation was 0.50 year–1. The longevity of the Chub mackerel was 7.60 years. The length based cohort analysis and the application of Beverton and Holt's yield per recruit models as well as Thompson and Bell's predictive model, revealed that the Scomber japonicus peruanus is over exploited and nearing it's maximum capacity.

A dinâmica populacional de Scomber japonicus peruanus (cavalinha) foi estudada com base nos dados de captura da pesca comercial obtidos mensalmente, de janeiro de 1990 a dezembro de 2003, no litoral peruano (3°23’S-18°20’S e 72°W-84°W), dentro do projeto “Seguimento de los recursos pelágicos en el litoral peruano" que vem sendo desenvolvido no Instituto del Mar del Perú – IMARPE. Nesse período, a Temperatura Superficial do Mar foi obtida mensalmente em cada uma das áreas de coleta. A análise dos parâmetros de crescimento e as taxas de mortalidade, bem como o padrão de recrutamento da cavalinha, foram feitos a partir dos dados da pesca comercial correspondente aos anos de 1996 a 2003, enquanto na avaliação do estoque utilizaram-se os do período de 1993 a 2003. A Temperatura Superficial do Mar variou de 13,60°C (2001) a 29,34°C (1998), sendo os valores mínimos encontrados em 1996 e 1999-2001 e máximos em 1992-1993 e 1997-1998. Os desembarques da espécie Scomber japonicus peruanus entre 1990 e 2003 variaram de 8.119 t a 387.659 t, sendo o valor médio 122.513 t. As médias dos desembarques mensais oscilaram entre 3.274 t e 16.853 t, com maiores valores registrados nos meses de novembro e dezembro de 1998, bem como em janeiro e março de 1999. As anomalias positivas máximas dos desembarques, que variaram de 134.985 t a 345.137 t, foram obtidas no período de 1997-1999 e em 2001, enquanto elevadas anomalias negativas nos anos de 1992 (-34.402 t) e 1993 (-32.894 t). Os resultados mostraram que no período de 1993-2003 o comprimento médio furcal da cavalinha diminuiu de 30,50 cm para 26,70 cm, que o comprimento furcal de primeira captura (Cf50) foi 26,40 cm e que o recrutamento ocorreu o ano todo, principalmente, no verão. xiii No período compreendido entre 1996 e 2003, o estudo do crescimento e mortalidade da cavalinha evidenciou que os valores do comprimento assintótico (Cf∞) e os da taxa de crescimento (K), obtidos pelo ELEFAN I e os registrados pelo método de Ford- Walford, foram 42,40 cm e 0,40 ano–1, respectivamente. O comprimento igual a zero (to) foi –0,37 ano–1 e a amplitude de oscilação (C) 0,40, enquanto os valores de Winter Point (Wp) 0,60 e o do índice de performance (φ) 2,86. A taxa média de mortalidade total (Z) obtida pela análise da curva de captura linearizada e pelo método de Beverton & Holt, foi 2,30 ano–1; a taxa de mortalidade por pesca (F) 1,97 ano–1 e a taxa de explotação 0,86 ano–1. A taxa anual de mortalidade natural (M) estimada pelo método de Rikhter & Efanov e pela equação de Pauly foi 0,50 ano–1. A longevidade da cavalinha foi 7,60 anos. A análise de coorte de comprimento e a aplicação dos modelos de rendimento por recruta de Beverton & Holt e o preditivo de Thompson & Bell, revelaram que o estoque de Scomber japonicus peruanus encontra-se sobre-explotado e próximo da capacidade máxima. / The population dynamics of the Scomber japonicus peruanus (Chub mackerel) was studied based on commercial fishing data obtained monthly from January 1999 to December 2003 off the Peru coast (3°23’S-18°20’S e 72°W-84°W), within the “Tracking of pelagic resources off the Peru coast" project which is being carried out at the Instituto del Mar del Peru – IMARPE. During this period, Sea Surface Temperature data was obtained monthly I n each one of the sampling areas. The analysis of the growth parameters, mortality rates, as well as the recruitment pattern of the Chub mackerel was obtained from commercial fishing data from 1996 to 2003. For stock assessment the time range was from 1993 to 2003. Sea Surface Temperature varied from 13.60°C (2001) to 29.34°C (1998) with minimum values being found in 1996 and 1999-2001 and maximum values in 1992-1993 and 1997-1998. The landing of the Scomber japonicus peruanus species between 1990 and 2003 varied from 8.119 t to 387.659 t, with an average of 122.513 t. The average of the monthly landings varied between 3.274 t and 16.853 t, with higher values registered on November and December 1998 as well as January and March 1999. The maximum positive anomalies of the landings, which varied from 134.985 to 345.137 t, were obtained in 1997 -1999 and in 2001. On the other hand, high negative anomalies were obtained in 1992 (-34.402 t) and 1993 (-32.894 t). The results show that from 1993 to 2003 the mean fork length of the Chub mackerel decreased from 30,50 cm to 26,70 cm, the fork length of the first catch (Cf50) was 26,40 and that recruitment occurred all year, especially during the summer. Between 1996 and 2003, the growth and mortality study of the Chub mackerel showed that the asymptotic body length (Cf∞) and the growth rate values (K) obtained by ELEFAN I and the ones xv registered by the Ford-Walford method were 42.40 cm and 0.40 cm year–1, respectively. The t-zero (length is 0) was –0.37 year–1 and the amplitude (C) 0.40. The Winter Point (Wp) value was 0.60 and the performance index (φ) 2.86. The mean total mortality rate (Z), obtained by analyzing the linearized catch curve and by the Beverton and Holt method, was 2.30 year–1. The rate of fishing mortality (F) was 1.97 year–1 and the exploitation rate 0.86 year–1. The annual rate of natural mortality (M) estimated by the Rikter and Efanov method and by the Pauly equation was 0.50 year–1. The longevity of the Chub mackerel was 7.60 years. The length based cohort analysis and the application of Beverton and Holt's yield per recruit models as well as Thompson and Bell's predictive model, revealed that the Scomber japonicus peruanus is over exploited and nearing it's maximum capacity.

The ability of high hydrostatic pressure (HHP) to extend the shelf life of Atlantic mackerel (Scomber scombrus) and red mullet (Mullus barbatus) was assessed in this study. For that purpose, fillets of both atlantic mackerel and red mullet were subjected to pressure treatments at 200, 300, 400 MPa at 5, 10, 15&deg / C for 5 and 15 minutes. The influence of the treatments on Trimethylamine Nitrogen (TMA-N) level, lipid oxidation stability (Thiobarbituric Acid, TBA level) was investigated as well as color changes. The suitable combinations for Atlantic mackerel were determined as 200 MPa, 15&deg / C for 5 min and 400 MPa, 5&deg / C for 5 min / and for red mullet 200 MPa, 15&deg / C for 5 min. In the second stage, the shelf life of fish samples, which were treated with these conditions and stored at 4&deg / C, were studied by measurement of pH, color, sensorial features (appearance and odor), TMA-N, TBA, Total Volatile Basic Nitrogen (TVB-N), Histamine and Total Mesophilic Aerobic Count (TMAC) formations. Based on these analyses, the unpressurised mackerel samples were acceptable up to only 7 days compared to 17 and 19 days after 200 and 400 MPa treatments / respectively. For red mullet samples pressurization at 200 MPa extended the shelf life an additional 3 days (from 1 week to 10 days). HHP treatment in combination with chilled storage can improve the shelf life and quality of fish.

En la presente tesis se estudió la factibilidad de caracterizar y modelar la tecnología de ahumado aplicada a una especie pesquera pelágica de Argentina, buscando a partir de las experiencias realizadas obtener un producto de alta calidad final. Se trabajó sobre la especie Scomber japonicus, teleósteo de acuerdo a la clasificación científica por tener un esqueleto óseo, por su tipo de hábitat marino se considera pelágico y por su contenido lipídico una especie grasa. Aproximadamente el 76% de las capturas en el Océano Atlántico Sudoccidental, donde se ubican los principales puertos de Argentina, están destinadas a su elaboración como conserva, siendo apreciada por la excelencia del producto que se obtiene. El porcentaje restante se exporta como pescado entero congelado, siendo, por lo tanto este producto y la conserva, los dos productos que se elaboran en Argentina con esta especie. Las estadísticas indican la posibilidad de expansión del mercado incluyendo productos diferentes. Es por ello que la aplicación de tecnologías tradicionales de procesamiento de pescado, como es el ahumado, se presentan como alternativas para el desarrollo de productos alimenticios de alta calidad nutricional. El presente trabajo de tesis fue desarrollado en la ciudad de Mar del Plata, caracterizada por su actividad portuaria permitiendo la disposición del recurso pesquero, de infraestructura y equipos para realizarla, con el objetivo de transferir a la industria los conocimientos aportados por el mismo. En este contexto, se analizaron experimentalmente las distintas etapas que componen el proceso de ahumado sobre la especie, desde la materia prima hasta el producto final listo para consumir, considerando tanto los aspectos fisicoquímicos y nutricionales como sensoriales y microbiológicos implicados.

Presence of coastal aquaculture activities in marine landscapes is growing. However, there is insufficient knowledge on the subsequent ecological interactions between these activities and marine fish communities. The overall aim of this thesis was to evaluate the direct and indirect ecological effects of aquaculture activities on marine fish communities in Scotland. A combination of empirical and modelling approaches was employed to collect evidence of how aquaculture activities affect marine fish communities at the individual, population and ecosystem levels around coastal sea cages. The two fish farms evaluated in this research provided the wild fish sampled near the sea cages with a habitat rich in food resources which is reflected in an overall better biological condition. Results of the stomach content analysis indicated that mackerel (Scomber scombrus), whiting (Merlangius merlangus) and saithe (Pollachius virens) sampled near sea cages consumed wasted feed which was also reflected in their modified FA profiles. The overall effects of the two fish farms were more pronounced in young whiting and saithe than in mixed aged mackerel sampled near the sea cages. The phase space modelling approach indicated that the overall potential for fish farms to act at the extremes as either population sources (a habitat that is rich in resources and leads to an overall improved fitness) or ecological traps (a habitat that appears to be rich in resources but is not and leads to an overall poor fitness) are higher for juvenile whiting than for mackerel. Based on the empirical evidence and literature the two fish farms are more likely to be a population source for wild fishes. Using an ecosystem modelling approach indicated that fish farming impacts the food web in a sea loch via nutrient loading. Mussel farming relies on the natural food resources and has the potential to affect the food web in a sea loch via competing with zooplankton for resources which can affect higher trophic levels. The presence of both activities can balance the overall impact in a sea loch as compared to the impact induced if each of these activities were present on their own. Both activities have the potential do induce direct and indirect effects on the wild fish and the entire sea loch system. The results of this PhD identified several gaps in data and thus could be used to improve future sampling designs. It is important to evaluate the cumulative effect of the presence of aquaculture activities in terms of nutrient loading and physical structure in the environment. Using a combination of empirical and modelling approaches is recommended to gain further insight into the ecological impacts of aquaculture activities on wild fish communities. Results of this PhD study could lead to more informed decisions in managing the coastal aquaculture activities. Establishing coastal fish farms as aquatic sanctuaries can be of an advantage to increase fish production and conserve species that are endangered provided that no commercial and recreational fishing is allowed nearby. It would be useful to have long term monitoring of the fish stocks around the cages and if there is any production at the regional level. Additionally, information on behaviour, migration patterns should be collected to understand the impacts of aquaculture activities on fish stocks. From an aquaculture perspective, ecologically engineered fish farms in addition to careful site selection in new aquaculture developments may improve nutrient loading into the ecosystem.