Problems in estimating the response functions of natural climatic recording systems [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): High-resolution proxy records of climate, such as varves, ice cores, and tree-rings, provide the opportunity for reconstructing climate on a year-by-year basis. In order to do so it is necessary to approximate the complex nonlinear response function of the natural recording system using linear statistical models. Three problems with this approach were discussed, and possible solutions were suggested. Examples were given from a reconstruction of Santa Barbara precipitation based on tree-ring records from Santa Barbara County.

Bycatch in marine fisheries

A review of the significant contributions in the peer-reviewed literature indicates that the discarding of marine fish known as bycatch remains one of the most significant problem facing fisheries managers. Bycatch has negative affects on marine biodiversity, is ripe with ethical and moral issues surrounding the waste of life from increased juvenile fish mortality, hinders commercial profitability and recreational satisfaction, increases management costs, and results in socio-cultural problems and conflicts. While appearing to have a simple conservation engineering solution, reducing or eliminating bycatch in marine fishing operations given the presently existing regulated open access management environment is demonstrated to actually be so complex that its effects can appear to be counter-intuitive. An ecosystem simulation model that explicitly incorporates the human and biological dimensions is used to evaluate proposed bycatch reduction regulations for two fishing fleets exploiting three out of seven species of fish, each with ten cohorts, in two resource areas. One of the fishing fleets is divided into two components representing commercial fishermen and recreational anglers. The seven fish species represent predator, prey, and competitor behaviors and one stock is treated as an endangered species. The results displayed in a series of figures demonstrate the potential unintended effects of simplistic management approaches and the need for a holistic and comprehensive approach to bycatch management. That is, an ecosystem model that explicitly incorporates socio-cultural and biophysical attributes into a common framework allows the magnitude and direction of behavioral responses to be predicted based on changes in governance or biophysical constraints to determine if management goals and objectives have been obtained through the use of quantitative metrics.

Present status and problems of mussel culture in India

Two species of mussels, the green mussel (Perna viridis) and the brown mussel (Perna indica) were cultured using the seed collected from the natural beds of the east and west coasts of India. The results of culture experiments are consolidated and the present status is reviewed. Although the culture experiments gave encouraging results, problems such as mooring of rafts in highly turbulent coastal waters, large scale seed requirements, control of predation, legal problems and marketing of end products require urgent attention before undertaking commercial operations. Some of the major problems of mussel culture are outlined for formulating effective management policies and their implementation for commercial mussel farming in India.

Quality problems in fish processing

Various problems associated with the quality of the fishery products like spoilage, discolouration, microbiological problems, etc., are outlined. The reasons and remedial measures are discussed. The importance of proper handling, processing and hygiene is stressed.