[Truncated abstract] Removal of consumers through fishing has been shown to influence ecosystem structure and function by changing the biomass and composition of organisms occupying lower trophic levels. The western rock lobster (Panurilus cygnus), an abundant consumer along the temperate west coast of Australia, forms the basis of Australia's largest single species fishery, with catches frequently exceeding 11000 tonnes annually. Despite their high abundance and commercial importance, the diet and trophic role of adult lobster populations in deep-coastal-ecosystems (35-60 m) remains unknown. An understanding of the diet and trophic role of lobsters in these ecosystems is a key component of the assessment of ecosystem effects of the western rock lobster fishery. This study uses gut content and stable isotope analyses to determine the diet and trophic role of lobsters in deep-coastal ecosystems. Dietary analysis indicated adult lobsters in deep-coastal ecosystems were primarily carnivorous with diet reflecting food available on the benthos. Gut content analyses indicate crabs (62 %) and amphipods/isopods (~10 %) are the most important lobster dietary sources. Stable isotope analysis indicates natural diet of lobsters in deep coastal ecosystems is dominated by amphipods/isopods (contributing up to ~50 %) and crabs (to ~75 %), with bivalves/gastropods, red algae and sponges of lesser importance (<10 % of diet each). Diet of lobsters in deep-coastal ecosystems differed from that reported for lobsters inhabiting shallow water ecosystems in this region, reflecting differences in food availability and food choice between these ecosystems. Bait from the fishery was also determined (by stable isotope analyses) to be a significant dietary component of lobsters in deep-coastal ecosystems, contributing between 10 and 80 % of lobster food requirements at some study locations. '...' Given observed effects of organic matter addition in trawl fisheries, and also associated with aquaculture, bait addition is likely to have implications for processes occurring within deep-coastal ecosystems in this region, particularly given its oligotrophic status, most likely by increasing the food available to scavenging species. Removal of lobsters from deep-coastal ecosystems may affect the composition and abundance of lobster prey communities through a reduction in predation pressure. Such effects have been demonstrated for other spiny lobster species. These effects are typically most observable amongst common prey taxa which in other studies have been commonly herbivores. In deep-coastal ecosystems, crabs and amphipods/isopods are the most common prey taxa and most likely to be effected. The ecosystem-impacts of top-down control of non-herbivorous prey species is unknown and constrains the inferences possible from this study. However, the establishment of 'no-take' areas in deep-coastal ecosystems would allow the ecosystem effects of lobster removal to be further assessed in these deep-coastal ecosystems. While data from the current study did not allow the ecosystem effects of lobster removal to be properly assessed, this study provided information regarding the ecology of western rock lobsters in previously unstudied ecosystems.

BARROSO, Juarez Coelho. Avaliação da Pesca da Lagosta Vermelha (Panulirus argus) e da Lagosta verde (Panulirus laevicauda) na Plataforma Continental do Brasil. 2012. 109 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2012 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T13:17:31Z No. of bitstreams: 1 2012_dis_jcbarroso.pdf: 2594115 bytes, checksum: ce2b67584a13e444ae16d1c1c08898f1 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T13:17:44Z (GMT) No. of bitstreams: 1 2012_dis_jcbarroso.pdf: 2594115 bytes, checksum: ce2b67584a13e444ae16d1c1c08898f1 (MD5) / Made available in DSpace on 2016-07-18T13:17:44Z (GMT). No. of bitstreams: 1 2012_dis_jcbarroso.pdf: 2594115 bytes, checksum: ce2b67584a13e444ae16d1c1c08898f1 (MD5) Previous issue date: 2012 / Extractive fishing lobster in Brazil is an important economic activity which includes different social sectors in the coastal region and provides an average annual income of USD$ 84 million. The great demand for the product, the high value in international market, expansion of the artisanal fleet, failure in enforce of conservation measures, the fishing impact on ecosystems and perhaps climate variability, have led to a high exploitation or overexploitation of the crustacean stocks. The evaluation and fishery prediction depends of biological and fisheries data collection, in the last two decades the absence of these data and the lack in the life cycle study generated a high level of uncertainty in the management of the fishery. In the present study, a comprehensive analysis is done of biological and fishery information generated by the thesis project and the data that precedes. The areas of the stock aggregation were distributed into 31 strata covering an area of 356.610 km², divided into two regions: shallow < 50 m (160.510 km²) and depth between 50 and 100 m (196.100 km²). The medium productivity index (1999-2006) between species was 29,75 kg/km² in Panulirus argus and 8,39 kg/km² in P. laevicauda; in different strata varied between 0.02 and 217.0 kg/km² (both species). Catchability coefficients ranged between 0.10 and 0.14, showing that the fishing gears (caçoeira, manzuá and cangalha) have a low efficiency in the lobster fishery. The sampling of landings between different fishing periods (1970-1979, 1980-1988 and 1989-1993) showed a progressive decrease in the small lobsters and as a result the mean length showed an increasing trend. The random samples on boats that fished between 20 and 35 m (1999), revealed that lobsters recruited (50 and 75 mm, Lc) accounted for 91% (P. argus) and 96% (P. laevicauda) of the total catch, which with the expansion of fishing (increased effort) was accompanied by a decreasing of the CPUE by fishing grids (between 1974 and 1991), showed a growth overfishing which are probably influencing in the high variations of the annual catches and its negative trend observed in the last fifteen years (1995-2009). The analysis between CPUE and abundance (N), revealed a lack of proportionality (hyperstability) between both parameters, which could be affecting the relationship between CPUE and effort and overestimating yield maximum sustainable (YMS). We estimated a yield maximum sustainable per unit area of 14 kg/km² and a yield maximum sustainable preliminary between 5,000 and 5,604 t. This empirical result should be confirmed through the development of stratified random sampling is proposed in this study. There is not evidence of recruitment overfishing in the stocks, but high rates of exploitation in the deep stock (50 to 100 m) of P. argus, composed mainly of older specimens and high reproductive power, could be accentuating the risk of low recruitment and collapse. This high level of uncertainty which takes the lobster fishery on the continental shelf of Brazil must be addressed by new ways of thinking, by a long-term and acquiring new skills and knowledge to develop fisheries sustainable. / A pesca extrativa de lagosta no Brasil é uma atividade econômica importante que engloba diferentes setores sociais na região costeira e que aporta um ingresso médio anual de 84 milhões de dólares. A grande demanda do produto, o elevado valor no mercado internacional, a expansão da frota artesanal, o não cumprimento das medidas de conservação, o impacto da pesca no ecossistema e possivelmente a variabilidade do clima, tem propiciado uma elevada explotação ou sobre-explotação dos estoques destes crustáceos. A avaliação e previsão da pescaria dependem da coleta de informação biológica e pesqueira, em que nas duas últimas décadas a ausência destes dados e a falta de estudo do ciclo de vida gerou um elevado nível de incerteza na administração da pescaria. No presente estudo, foi realizada uma análise integral da informação biológico-pesqueira gerada pelo projeto de mestrado e pelos dados que o precedem. As zonas de agregação dos estoques pesqueiros se distribuíram em 31 estratos que cobrem uma área de 356.610 km², divididos em duas regiões: rasa < 50 m (160.510 km²) e profunda entre 50 e 100 m (196.100 km²). O índice de produtividade médio (1999-2006) entre espécies foi de 29,75 kg/km² em Panulirus argus e de 8,39 kg/km² em P. laevicauda; nos diferentes estratos variou entre 0,02 e 217,0 kg/km² (ambas as espécies). Os coeficientes de capturabilidade variaram entre 0,10 e 0,14, demonstrando-se que os aparelhos de pesca (caçoeira, manzuá e cangalha) apresentam uma baixa eficiência na pescaria de lagosta. A amostragem dos desembarques entre diferentes períodos de pesca (1970-1979, 1980-1988 e 1989-1993) mostrou uma diminuição progressiva das lagostas pequenas e, como resultado, o comprimento médio mostrou uma tendência crescente. As amostragens aleatórias nas embarcações que pescaram entre 20 e 35 m (1999) revelaram que as lagostas recrutadas (50 e 75 mm, CC) representaram 91% (P. argus) e 96% (P. laevicauda) do total capturado, que conjuntamente com a expansão da área de pesca (aumento do esforço) e a diminuição da CPUE por quadrículas de pesca (entre 1974 e 1991), evidenciaram uma sobrepesca de crescimento que provavelmente esteja influenciando nas elevadas variações das capturas anuais e em sua tendência negativa observada nos últimos 15 anos (1995-2009). A análise realizada entre a CPUE e a abundância (N), revelou uma falta de proporcionalidade (hiperestabilidade) entre ambos os parâmetros, que poderia estar afetando a relação entre a CPUE e o esforço, e sobre-estimando as estimativas do rendimento máximo sustentável (RMS). Foi estimado um rendimento máximo sustentável por unidade de área de 14 kg/km² e um rendimento máximo sustentável preliminar entre 5.000 e 5.604 t. Este resultado empírico deve ser corroborado a partir do desenvolvimento da amostragem aleatória estratificada que foi proposto no presente estudo. Não existem evidências de uma sobrepesca de recrutamento nos estoques, mas as altas taxas de explotação no estoque do setor profundo (50 e 100 m) de P. argus, composto principalmente por exemplares mais velhos e de elevado poder reprodutor, poderia estar acentuando o risco dos recrutamentos baixos e dos colapsos. Este grande nível de incerteza pelo que transcorre a pescaria de lagosta na plataforma continental do Brasil deve ser abordado por formas de pensar novas e diferentes, por uma visão em longo prazo e pela obtenção de novos conhecimentos científicos que permitam desenvolver uma pesca sustentável.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / A pesca extrativa de lagosta no Brasil à uma atividade econÃmica importante que engloba diferentes setores sociais na regiÃo costeira e que aporta um ingresso mÃdio anual de 84 milhÃes de dÃlares. A grande demanda do produto, o elevado valor no mercado internacional, a expansÃo da frota artesanal, o nÃo cumprimento das medidas de conservaÃÃo, o impacto da pesca no ecossistema e possivelmente a variabilidade do clima, tem propiciado uma elevada explotaÃÃo ou sobre-explotaÃÃo dos estoques destes crustÃceos. A avaliaÃÃo e previsÃo da pescaria dependem da coleta de informaÃÃo biolÃgica e pesqueira, em que nas duas Ãltimas dÃcadas a ausÃncia destes dados e a falta de estudo do ciclo de vida gerou um elevado nÃvel de incerteza na administraÃÃo da pescaria. No presente estudo, foi realizada uma anÃlise integral da informaÃÃo biolÃgico-pesqueira gerada pelo projeto de mestrado e pelos dados que o precedem. As zonas de agregaÃÃo dos estoques pesqueiros se distribuÃram em 31 estratos que cobrem uma Ãrea de 356.610 kmÂ, divididos em duas regiÃes: rasa < 50 m (160.510 kmÂ) e profunda entre 50 e 100 m (196.100 kmÂ). O Ãndice de produtividade mÃdio (1999-2006) entre espÃcies foi de 29,75 kg/km em Panulirus argus e de 8,39 kg/km em P. laevicauda; nos diferentes estratos variou entre 0,02 e 217,0 kg/km (ambas as espÃcies). Os coeficientes de capturabilidade variaram entre 0,10 e 0,14, demonstrando-se que os aparelhos de pesca (caÃoeira, manzuà e cangalha) apresentam uma baixa eficiÃncia na pescaria de lagosta. A amostragem dos desembarques entre diferentes perÃodos de pesca (1970-1979, 1980-1988 e 1989-1993) mostrou uma diminuiÃÃo progressiva das lagostas pequenas e, como resultado, o comprimento mÃdio mostrou uma tendÃncia crescente. As amostragens aleatÃrias nas embarcaÃÃes que pescaram entre 20 e 35 m (1999) revelaram que as lagostas recrutadas (50 e 75 mm, CC) representaram 91% (P. argus) e 96% (P. laevicauda) do total capturado, que conjuntamente com a expansÃo da Ãrea de pesca (aumento do esforÃo) e a diminuiÃÃo da CPUE por quadrÃculas de pesca (entre 1974 e 1991), evidenciaram uma sobrepesca de crescimento que provavelmente esteja influenciando nas elevadas variaÃÃes das capturas anuais e em sua tendÃncia negativa observada nos Ãltimos 15 anos (1995-2009). A anÃlise realizada entre a CPUE e a abundÃncia (N), revelou uma falta de proporcionalidade (hiperestabilidade) entre ambos os parÃmetros, que poderia estar afetando a relaÃÃo entre a CPUE e o esforÃo, e sobre-estimando as estimativas do rendimento mÃximo sustentÃvel (RMS). Foi estimado um rendimento mÃximo sustentÃvel por unidade de Ãrea de 14 kg/km e um rendimento mÃximo sustentÃvel preliminar entre 5.000 e 5.604 t. Este resultado empÃrico deve ser corroborado a partir do desenvolvimento da amostragem aleatÃria estratificada que foi proposto no presente estudo. NÃo existem evidÃncias de uma sobrepesca de recrutamento nos estoques, mas as altas taxas de explotaÃÃo no estoque do setor profundo (50 e 100 m) de P. argus, composto principalmente por exemplares mais velhos e de elevado poder reprodutor, poderia estar acentuando o risco dos recrutamentos baixos e dos colapsos. Este grande nÃvel de incerteza pelo que transcorre a pescaria de lagosta na plataforma continental do Brasil deve ser abordado por formas de pensar novas e diferentes, por uma visÃo em longo prazo e pela obtenÃÃo de novos conhecimentos cientÃficos que permitam desenvolver uma pesca sustentÃvel. / Extractive fishing lobster in Brazil is an important economic activity which includes different social sectors in the coastal region and provides an average annual income of USD$ 84 million. The great demand for the product, the high value in international market, expansion of the artisanal fleet, failure in enforce of conservation measures, the fishing impact on ecosystems and perhaps climate variability, have led to a high exploitation or overexploitation of the crustacean stocks. The evaluation and fishery prediction depends of biological and fisheries data collection, in the last two decades the absence of these data and the lack in the life cycle study generated a high level of uncertainty in the management of the fishery. In the present study, a comprehensive analysis is done of biological and fishery information generated by the thesis project and the data that precedes. The areas of the stock aggregation were distributed into 31 strata covering an area of 356.610 kmÂ, divided into two regions: shallow < 50 m (160.510 kmÂ) and depth between 50 and 100 m (196.100 kmÂ). The medium productivity index (1999-2006) between species was 29,75 kg/km in Panulirus argus and 8,39 kg/km in P. laevicauda; in different strata varied between 0.02 and 217.0 kg/km (both species). Catchability coefficients ranged between 0.10 and 0.14, showing that the fishing gears (caÃoeira, manzuà and cangalha) have a low efficiency in the lobster fishery. The sampling of landings between different fishing periods (1970-1979, 1980-1988 and 1989-1993) showed a progressive decrease in the small lobsters and as a result the mean length showed an increasing trend. The random samples on boats that fished between 20 and 35 m (1999), revealed that lobsters recruited (50 and 75 mm, Lc) accounted for 91% (P. argus) and 96% (P. laevicauda) of the total catch, which with the expansion of fishing (increased effort) was accompanied by a decreasing of the CPUE by fishing grids (between 1974 and 1991), showed a growth overfishing which are probably influencing in the high variations of the annual catches and its negative trend observed in the last fifteen years (1995-2009). The analysis between CPUE and abundance (N), revealed a lack of proportionality (hyperstability) between both parameters, which could be affecting the relationship between CPUE and effort and overestimating yield maximum sustainable (YMS). We estimated a yield maximum sustainable per unit area of 14 kg/km and a yield maximum sustainable preliminary between 5,000 and 5,604 t. This empirical result should be confirmed through the development of stratified random sampling is proposed in this study. There is not evidence of recruitment overfishing in the stocks, but high rates of exploitation in the deep stock (50 to 100 m) of P. argus, composed mainly of older specimens and high reproductive power, could be accentuating the risk of low recruitment and collapse. This high level of uncertainty which takes the lobster fishery on the continental shelf of Brazil must be addressed by new ways of thinking, by a long-term and acquiring new skills and knowledge to develop fisheries sustainable.