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Selasa, 07 Juli 2009

Statistical Design and Experimental Endpoints

Statistical Design
The number of animal subjects required for an investigation will depend on the questions being explored. Field studies and laboratory studies typically require greatly different statistical designs, with field studies typically requiring much larger numbers. The life stage of the fish used in each study will also affect the numbers needed. Studies of early life stages typically require very large numbers of individuals. In all cases, studies should be designed to use the fewest animals necessary to reliably answer the questions posed.
The use of adequate numbers to establish variance and to assure reliability is essential so as to prevent needless repetition of the study (ASIH et al. 1987, 1988). A true "replicate" is the smallest experimental unit to which a treatment can be applied independently.
Pseudoreplication can result from wrongly treating multiple samples from one experimental unit as multiple experimental units or from using experimental units that are not statistically independent (Heffner et al. 1996). Study objectives should be presented as clearly stated hypotheses, and explanations should be provided as to the need for the type and quantity of data to be collected as well as what will constitute an end to the experiment. Power analysis procedures have been useful to many researchers to determine the appropriate number of fish needed to accomplish acceptable, statistically valid results. Researchers are encouraged to consult with a statistician to develop study designs that have the appropriate statistical power to accomplish research objectives.

Mortality as an Experimental Endpoint
In general, experimental endpoints other than death of the experimental subjects should
be developed unless death is required by the study protocol. The use of mortality as an
endpoint is appropriate when one or both of the following criteria are met:
(1) Little or no information pertaining to research objectives is available on the species of interest or the experimental variable being imposed. (For example, shortterm, limited mortality studies may be used to develop experimental limits for subsequent sublethal studies.)
(2) Mortality data are required or at least used frequently by a sponsoring agency to provide a basis for criteria development as part of a regulatory process. Many studies concerning the effects of pathogens and parasites or studies concerning the effects of drugs and other chemicals require mortality endpoints.

Quality Assurance Plans and Standard Operating Procedures

Quality assurance plans (QAPs) and standard operating procedures (SOPs) are not required by many universities or nongovernmental institutions; nevertheless, the concepts upon which these documents are based are recommended as useful tools for maintaining overall research quality.
The QAPs and SOPs usually are required if research data and conclusions will be submitted to certain regulatory agencies, such as the Food and Drug Administration (FDA) or the U.S. Environmental Protection Agency (USEPA). Specific benefits that can
result from the establishment and use of QAPs and SOPs include the following: consistency in repeated procedures, limiting unneeded replications, obtaining the most
information possible from the fewest fish and staff, and developing sets of data that can
withstand legal challenges.
The QAP is a written document that describes the principles, policies, organizational responsibilities, objectives, implementation actions, and accountability procedures that
will ensure appropriate quality throughout a research project. The QAPs document management procedures and ensure that the data collected will qualify for meeting study objectives. The QAPs should be detailed enough to provide clear descriptions of every aspect of the project. They facilitate communications and help to keep projects on
schedule and within budget. An important matter that is overlooked frequently in QAPs is tracking and limiting access to research facilities and animals. The quality of research, and even the welfare of experimental animals, can be compromised if access is not controlled and tracked. Posting signs and providing signin and signout sheets help to ensure that other provisions in the QAPs are followed.
Typically, QAPs are prepared by the principal investigator and are subject to approval by that individual’s supervisor(s) and the IACUC. Copies of QAPs should be kept in designated, readily accessible locations in the office of the principal investigator and the
department or section where the study will be conducted.
Standard operating procedures document routine or repetitive technical activities, ensuring that work is done correctly the first time, thereby reducing unnecessary repetition and costs. Examples of specific technical tasks that may be used to conduct
research with fishes include the following: blood sampling, vaccination protocols, procedures for electrofishing, or techniques for collecting meristic data. The SOPs promote consistency in quality and integrity of data and are useful for maintaining consistency when there are changes in personnel. They also can form an essential part of effective training programs. General SOPs, not specific to individual studies, may be
established as basic procedures for entire research institutions or laboratories. Additional information on SOPs and QAPs is available from regulatory agencies such as USEPA or FDA and from various manuals or texts that address quality assurance.

Kamis, 02 Juli 2009


The fishery for lemuru (Sardinella longiceps) in the Bali Strait is one of the main small pelagic fisheries in Indonesia. This fishery is very specific as it exploits a single species and it is concentrated in a relatively narrow area. Fishing has been largely conducted by fishermen from the Bali Province and Muncar (East Java Province).
Fishermen from both sides of the Strait have benefited from the development of lemuru fishery. Over time the number of fishermen has increased and fishing technology has improved. Following the adoption of fishing by purse seine in 1974 the catch increased rapidly, which has resulted in an increase in the number of processing units. Canning factories were built in the coastal area of Bali Province and of Muncar District of the East Java Province. Similar development also took place as regards the increase in construction of fishmeal processing units on both sides of the strait.
Various studies have been conducted in this fishery. Several studies on resources,
oceanography, post harvest and socio-economic aspects have been carried out by the staff of RIMF and also some students from various Universities in Java and Bali. The fishery also attracted foreign interest as early as the 1970s when a student from the University of Hawaii completed his MSc thesis based on his research on the population biology of lemuru in the Bali Strait in 1973. In a later year, some staff of Brawidjaya University, in cooperation with the staff of the Wageningen University in Holland, also conducted research on the socio-economic aspects of fishermen in the Bali Strait.
The dynamic nature of small pelagic resources such as lemuru has resulted in the fluctuation of catch and thus the supply of raw material for the processing industry. The rapid increase in the number of fishing boats has also caused great concern re its impact on the resources. In response to these concerns on the situation of the fishery, the central Government (represented by the Directorate General of Fisheries) and the Provincial Governments bordering the Bali Strait (represented by the Provincial Fisheries Office of East Java and of Bali) held several workshops to address fisheries problems. These initiatives led to a greater effort in the management of the fishery under the responsibility of the two Provincial Governments. The joint agreement in 1977 stipulated allocation of fishing for the two provinces. Gradually, the subsequent development in the fisheries has led to the two provincial governments revising management measures to meet the continued challenge faced by the fisheries. In particular, the rapid development of the fisheries has not been accompanied by comparable effort in their management. Monitoring of the fishery has been weak, let alone the enforcement of the law as
stipulated in the joint management. This review study is aimed at helping readers to address the right questions in the current stage of fisheries, a major step in developing a management plan for the fisheries.