Fisherman accidentally caught sea turtles in their fishnet. It could be dangerous for its population. This study measures the turtle target strength (TS) using modified echosounder. The result could be used to improve the efficiency of turtle repellent device. The experiment conducted in a hatchery fiber tank contained saline water. The Green were 1, 3, 12 and 18 years old. The study used three species of fish to ensure there are no overlapped value between fish and sea turtle. TS of the animals were calculated incorporating reference targets (sphere). The echo power of the turtle was compared with the solid steel sphere which is confirmed good agreements with the theoretical values. The echo power reference by applying Fast Fourier Transform (FFT) analysis has been used in calculating TS of the animal. From the echo evaluation in time domain at different angles, it is obviously shown that echo signal structure is different between the parts of turtle body. This study reveals that high echo strength is acquired from the carapace and the plastron parts. The finding also showed that there are significant differences between 3, 12, 18 years old turtles and fish in every angle measurement.

A half-cutting fish cutting machine was designed, fabricated and evaluated for performance. The major components of the machine were made up of three main parts: mainframe (case), conveyor/rotator and cutter component. The conveyor and disc cutter are powered by a single phase, 1400rpm and 1hp electric motor. Analysis on size (length, width, depth) of fish, size of disc cutter and gap of roller at the cutter component had been made. The performance of the machine was evaluated using 5 types of major fish that used for salted fish industry. The results showed that this machine can produced 5 times more productivities compared to existing (manual) method. From the analysis data, the machine can produce an average of 21 fish/minute, so the average time to half-cutting 1000 fishes is 47 minutes. More energy saving and less labor needed for fish cutting process. Also, 81.2% significant time saving were obtained from this machine. This new innovation is an alternative choice to existing heavy-duty machines in the market with more expensive cost.

Acoustic is a common method for underwater object classification and to

Abstract-the acoustic power at difference angle and distance were measure for four different ages of Green Turtles and three species of fish using modified echo sounder V1082. The echo signal from TVG output was digitized at a sampling rate 1MHz using analog to digital converter (Measurement Computing USB1208HS). Animals were tied with wood frame to ensure it can't move away from the sound beam. The scatter value for fish demonstrates echo strength is different and depends on the angle of measurement. The lowest acoustic power of fish was recorded from their tail. The finding show that, there is significant difference between fish and turtles aged 12 to 18 years at 4.5 meter and 5 meter. The carapace and plastron of sea turtle gives high backscattering strength compare to other side. The high value obtained probably because of the hard surface of the carapace and plastron. This result is considered important in determining the best method of separating sea turtle and fish. Through this result, revealed that size, surface and animal angle play important role in determining acoustic strength value.

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