RESUMO
Ocean acidification and increased ocean heat content has direct and indirect effects on marine organisms such as holothurians (sea cucumbers) that are vulnerable to changes in pH and temperature. These environmental factors have the potential to influence organismal performance and fitness at different life stages. Tropical and temperate holothurians are more vulnerable to temperature and pH than those from colder water environments. The high level of environmental variation observed in the oceans could influence organismal responses and even produce a wide spectrum of compensatory physiological mechanisms. It is possible that in these areas, larval survival will decline by up to 50% in response to a reduction of 0.5 pH units. Such reduction in pH may trigger low intrinsic growth rates and affect the sustainability of the resource. Here we describe the individual and combined effects that temperature and pH could produce in these organisms. We also describe how these effects can scale from individuals to the population level by using age-structured spatial models in which depensation can be integrated. The approach shows how physiology can improve the conservation of the resource based on the restriction of growth model parameters and by including a density threshold, below which the fitness of the population, specifically intrinsic growth rate, decreases.
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The framework proposed by Ostrom (2009) has become one of the most utilized tools to address the complexity of social-ecological systems. Most cases use this framework to analyze the systems from the perspective of a single resource unit. However, the livelihoods in several coastal communities are diverse, so that the users interact with multiple common-pool resources, which makes their analysis difficult. In this sense, it is important to identify the key elements of management to achieve the sustainable use of the resources. In this study, we were able to do this in a coastal community where commercial fishing, ecotourism, and recreational fishing coexist. The system of interest, located in the state of Quintana Roo, Mexico, was subdivided by resource type using a multi-method approach to data collection including surveys, interviews, and records review. A conceptual map was developed that shows how the second-tier variables are integrated through the governance and actors with the biophysical system. The actors involved in lobster fishing achieved a more complex governance system, followed by the ecotourism and recreational fishing; the complexity of the governance was related with the equity level of the actors. The analysis revealed the research gaps to develop management strategies and improve the sustainability of the system.
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Diving fisheries are an important source of income and protein for many coastal communities around the world. However, these fisheries are also the cause of both fatal and non-fatal injuries. The aim of this study is to estimate the costs of decompression sickness (DCS) in the diving small-scale fisheries that target benthic resources in the Yucatan, Mexico. The DCS cases that occurred during three fishing seasons for sea cucumber (Isostichopus badionotus) and one for spiny lobster (Panulirus argus) were used to calculate the direct medical costs. The catch data during the same fishing seasons were used to calculate the potential losses caused by disability as indirect costs. In the three years (from 2013 to 2016) the total number of fishermen treated in the region numbered 282; 116 during lobster fishing and 166 during sea cucumber season. The direct medical costs were estimated to be USD $120,269; the temporary loss of income in USD $724,377; and the permanent loss of income was USD $737,053. Considering the direct and indirect costs, the social costs of diving in both small-scale fisheries was USD $1,614,121. This is a first approach to estimate the cost of the use of diving in fisheries for the health services but for the fishing communities as well. Furthermore, this is an important first step on the road to a full economic evaluation of the benthic fisheries in order to improve their management.
Assuntos
Efeitos Psicossociais da Doença , Doença da Descompressão/economia , Mergulho/economia , Pesqueiros/economia , Custos de Cuidados de Saúde , Doenças Profissionais/economia , Absenteísmo , Adulto , Animais , Custos e Análise de Custo , Doença da Descompressão/terapia , Mergulho/efeitos adversos , Síndrome Neurológica de Alta Pressão/etiologia , Hospitalização/economia , Humanos , Oxigenoterapia Hiperbárica/economia , Renda , México , Pessoa de Meia-Idade , Doenças Profissionais/terapia , Palinuridae , Pepinos-do-Mar , Estações do AnoRESUMO
Due to the heavy exploitation of holothurians over the last few decades, it is necessary to implement fishing regulations aimed at reversing this situation. Holothurians require specific regulations that take into account their biology and ecology. Their behavior to group and form patches as a strategy for feeding, defense and reproduction, makes them vulnerable to overfishing. The higher the population density, the higher the catchability coefficient, and because they are sedentary organisms, the catchability does not change significantly until the density is very low. Hence, the stock assessment of holothurians can be improved by analyzing their spatial distribution. This paper proposes a stock assessment technique that considers the spatial distribution pattern of the sea cucumber Isostichopus badionotus from Yucatan, Mexico. A bioeconomic spatial model was developed to explain the interactions between fishing effort allocation, quasi-profits and the population in the short term. Because of the high price of the species and the low production costs, artisanal fishers preferred to maximize short-term quasi-profits, rather than the long-term benefits they could gain with low fishing mortality rates.
Assuntos
Pesqueiros , Modelos Econômicos , Pepinos-do-Mar , Animais , MéxicoRESUMO
Age and growth analysis is essential to fisheries management. Indirect methods to calculate growth are widely used; however, length frequency data analysis in sea cucumbers is complicated by high data variability caused by body wall elasticity. Here we calculated Isostichopus badionotus parameters of the von Bertalanffy growth function. In order to address bias produced by body wall elasticity, we compared the performance of four measurements and one compound index that combines different biometric parameters: the square root of the length-width product (SLW). Results showed that variability in length data due to body wall elasticity was controlled by using body length (Le) from the SLW compound index. Growth in I. badionotus follows a negative allometric tendency. Slow or zero growth periods were observed during October and November, when weather conditions were adverse.