Large sardinella (Sardinella maderensis and Sardinella aurita) in warm waters off the coast of Africa are known to be a challenge for pelagic trawl sampling, for example during acoustic surveys for abundance estimation. We observed the swimming behaviour of sardinella mixed with other pelagic species, mainly Cunene horse mackerel (Trachurus trecae), during sampling with a pelagic trawl in the c...

We analysed relationships between demersal fish species richness, environment and trawl characteristics using an extensive collection of trawl data from the oceans around New Zealand. Analyses were carried out using both generalised additive models and boosted regression trees (sometimes referred to as ‘stochastic gradient boosting’). Depth was the single most important environmental predictor ...

We analysed relationships between demersal fish species richness, environment and trawl characteristics using an extensive collection of trawl data from the oceans around New Zealand. Analyses were carried out using both generalised additive models and boosted regression trees (sometimes referred to as “stochastic gradient boosting”). Depth was the single most important environmental predictor ...

For prawn trawling systems, drag reduction is a high priority as the trawling process is energy intensive. Large benefits have occurred through the use of multiple-net rigs and thin twine in the netting. An additional positive effect of these successful twine-area reduction strategies is the reduced amount of otter board area required to spread the trawl systems, which leads to further drag red...

—The use of fisheries-independent trawl survey data to estimate fish abundance in shallow coastal systems can present challenges for producing reliable population estimates. We used hydroacoustic and trawl data to estimate the catch efficiency of a demersal trawl that is presently used in surveys to support stock assessments in Chesapeake Bay, USA. Specifically, we determined the efficiency of ...

Media Independent Handover (MIH) is an emerging standard which supports the communication of network-critical events to upper layer mobility protocols. One of the key features of MIH is the event service, which supports predictive network degradation events that are triggered based on link layer metrics. For set route vehicles, the constrained nature of movement enables a degree of network perf...

Abstract: Aiming at improving the security of a semi-pelagic trawl in a complex working environment, this paper proposes a threedimensional tracking control system for the guidance of a semi-pelagic trawl on a complicated trajectory. The flexible nonlinear trawl system is simplified as a mass-spring-bar model. A hierarchical backstepping controller is then designed for the trajectory tracking o...

Economic comparison of single-rig and twin-rig trawl for nephrops Economic comparison of single-rig and twin-rig trawl for nephrops

The effects of reducing mesh size while concomitantly varying the side taper and wing depth of a generic penaeid-trawl body were investigated to improve engineering performance and minimize bycatch. Five trawl bodies (with the same codends) were tested across various environmental (e.g. depth and current) and biological (e.g. species and sizes) conditions. The first trawl body comprised 41-mm m...

Tests of trawl footrope modifications to reduce the bycatch of eulachon (Thaleichthys pacificus) and other small demersal fishes in the ocean shrimp (Pandalus jordani) trawl fishery The Oregon Department of Fish and Wildlife prohibits discrimination in all of its programs and services on the basis of race, color, national origin, age, sex or disability. If you believe that you have been discrim...