During tests/demonstration shrimp catches have, in general, been high, often two, three, or more hundreds of kilogrammes for half-hour tows.

By-catch consisted, in general, in small fishes almost same size than shrimp, small pelagic fishes as well as juveniles of small commercial fishes; on certain fishing grounds catches of stingray, small sharks and jellyfish were considerable.

Compared to the standard diamond mesh codend, the square mesh window (SMW) caught 30% more shrimp, maintained commercial fish catches and reduced bycatch by 29%. Compared to the SMW +Cone combination, the SMW caught 53% more shrimp, 100% more commercial fish and 30% more bycatch. This latter test should be treated with caution as it was performed only once and fouling of the catch around the hoop (in the SMW + Cone combination) resulted in considerable catch loss.

The SMW + Cone combination caught 15% less shriinp, 17% less commercial fish and 28% less bycatch when compared to the standard codend. Shrimp catch rates were, however, highly variable, ranging from less than one basket to almost 42 baskets. On the FV Tabas, the SMW caught 4.5% more shrimp, 33% less commercial fish and 75% less bycatch.

The Fisheye was tested against the standard codend and also in a Fisheye + Cone combination against the SMW. Compared to the standard codend the Fisheye reduced shrimp catches by 22% and bycatch by 32%. There was no loss of commercial fish. Compared to the SMW, the Fisheye + Cone combination caught 41% less shrirnp, 25% less commercial fish and 58% less bycatch.

The NAFTED was also compared against the SMW + Cone combination. There was a 2% loss of shrimp, a 50% reduction of commercial fish, and the number of baskets of bycatch was reduced by 35%. Stingrays with a disc width of less than l m dominated the bycatch and the NAFTED reduced these animals by 95%.

The rope BRD was tested for one shot only. Compared to the standard codend there was no loss of shrimp or conunercial fish and a 25% reduction in bycatch.

As already mentioned, catch sub-samples of shrimp and fish from five 30 minute shots were taken during the last few days of the tests. From the sub-samples the weight and carapace length of P. mergitiensis and M. affinis from both sides was measured. During this time the port side trawl was fitted with a standard codend while the starboard trawl was fitted with a SMW + Cone combination. The results suggest that no obvious size classes were apparent although a wider length range of M. affinis was caught.

The underwater video system was only available for two days due to difficulties bringing the system into Iran. Adverse weather on the eve of the video tests reduced water visibility so that recording was not possible on the seabed, despite attempts in depths ranging from 8 m to 28 m. However, some useful footage was obtained during deployment and hauling of the trawls at 3 to 5 m below the sea surface.

For instance, after a cone had been installed in the trawl, the video footage showed that the cone was forced upwards against the top of the codend as the trawl moved through the water, thereby only blocking the upper portion of the codend. While the cone is designed to partially block the codend (and stimulate fish to swim forward and through the escape openings in the BRD), it is not known if the effectiveness of the cone was reduced when operated in this position.

Video footage also showed fish and shrimp surging forward when the codend was on the surface (prior to hauling the codend onboard). This can be a source of high shrimp loss as these animals may reach the escape openings of the BRD and escape.

Poor visibility prevented taking footage of fish behaviour.