Bioenergetics model 欧阳明艳 2018.4.4

What is bioenergetics? The study of the flow and transformation of energy in and between living organisms and their environment.

The bioenergetics model is exactly based on bioenergetics and has been widely applied to problems and issues in fishery ecology around the world . Bioenergetics models can aid in understanding energy intake and utilization. The construction of a bioenergetics model is complex because the energetic costs and benefits of all physiological activities must be accounted. Fish bioenergetics model has been used to : 1.Better understand fish growth and food consumption in lake, rivers and ocean. 2.Predict changes in growth and food consumption of fish under various climate change. 3.Estimate the strength of predator-prey trophic links in aquatic food webs. 4.Determine the role of fish in cycling nutrients in aquatic ecosystems. 5.Identify the major factors regulating containment accumulation in fishes.

C = R + E + P C :the energy consumed (income) The bioenergetics model calculates fish growth by solving the energy equation: C = R + E + P C :the energy consumed (income) R : the energy used in respiration E：the energy excreted P : the energy remaining for production The energy costs of different activities can be estimated either by direct calorimetry (measuring the heat produced by an organism)or some form of indirect calorimetry such as measuring oxygen consumption.

Given initial fish weight, and user defined, temporally varying P-values and habitat information regarding temperature and prey, the model calculates growth over time based on energy balance and species specific energetic equations for consumption respiration, egestion and excretion. P-values=proportion of maximum cosumption

The model can be run in three different simulation modes: 1.The first model take inputs as described above and outputs fish growth. 2.Total consumption is instead used as an input, and average P-values are calculated. 3.Total consumption is input by user and average P-values are calculated. While only a single species of fish can be modeled with each run of the model, multiple sites can be modeled at the same time, for any users specified time period.

The limitation of bioenergetics model Despite frequent application, fish bioenergetics models have several limitations at present. 1.More evaluations of model performance are needed to identify conditions under which model performance in the laboratory and field. But more effort is needed to fully evaluate the suitable of available fish bioenergetics models. 2.Fish bioenergetics models are still unavailable for many species of fish. 3.The fish bioenergetics software contains “bugs” and is out of date. Certainly, there is a need to correct the errors in the software and to modernize the software approach, while still allowing the software to be easily applied by users.

4.The current versions of the fish bioenergetics models have no sex-specific resting from survey work, as well as results telemetry studies, have indicated that adult male fish are more active than adult female fish and that resting metabolic rate is higher in adult males than in adult females.

Progress in the study of bioenergetics models for fish The bioenergetics models have been widely used in fisheries management. Most models were developed using indirect data from other studies or even other species, this paper reviews the development and validation of bioenergetics models for four species of fish. All the four models were developed based on detail data on the bioenergetics of the species modelled. Performance of the models for the omnivorous European minnow and the herbivorous grass carp was poor, while models for the pisivorous mandarin fish and Chinese snakehead provide accurate predictions of growth. Analysis of the models for minnow and the grass carp suggested that inaccurate prediction of metabolic rates and bioenergetics models should be refined and rigorously validated before being used for fisheris management.

A bioenergetics model for juvenile flounder Platichthys flesus The paper mainly states the process and theory of the construction of bioenergetics models , and finally found that the model predictions closely tracked the observed changes of consumption and growth. The author also found that the temperature plays an important role in the growth of Flounder. The author suggested that a sex-specific estimation of energetic costs of spawning in adult Flounder and a more accurate description of the thermal history of fish may reduce the mistake in model prediction.

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