A B S T R A C TIncreasing regulations, bycatch restrictions, and concerns over ecosystem impact are now the driving forces for much of the development in fishing gear design occurring world-wide. Industry, government, and universities have responded to these challenges with major advancements in computer aided design, simulation, physical modeling techniques, and worldclass testing facilities. Model studies are a critical step in the development of new fishing gears and flume tanks are the de facto standard for investigating their attributes and performance under controlled conditions. This paper discusses the nature of flume tanks, their attributes, as well as the science and art of building and testing scale models of fishing gear. Footnote

Remote cameras are an increasingly important tool in field-based biological research. Terrestrial researchers can purchase inexpensive off-the-shelf cameras, but aquatic researchers face challenges in adopting similar systems for underwater science. Although technology allows researchers to deploy cameras in any aquatic environment, high procurement costs are often a barrier, particularly for studies that require the collection of lengthy videos. In this note, we provide a detailed guide explaining how to assemble an underwater camera system for less than $425 USD. We focus especially on the construction of the underwater housing, which is typically the most expensive component of an underwater camera system. As described, this system can record 13 h full high-definition videos in depths up to 100 m. It can be constructed and assembled with limited technical background using tools available in most workshops. The guide includes a general overview of the system, a full list of components, detailed instructions on constructing the camera housing, and suggestions on how to mount and use the camera in fieldwork. Our goal for this note is to promote the wider use of remote underwater cameras in aquatic research by making them accessible to those with limited financial means.

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a b s t r a c tA Canadian demersal survey trawl (Campelen 1800) was used to investigate the differences in trawl geometry and resistance using dynamic simulation, flume tank testing, and full-scale at-sea observations. A dynamic simulation of the trawl was evaluated using DynamiT software. A 1:10 scale model was built and tested in a flume tank at the Fisheries and Marine Institute of Memorial University of Newfoundland (Canada). Full-scale observations of the Campelen 1800 in action were collected during the 2011 fall multi-species survey aboard the research vessel CCGS Teleost. The numerical and physical modelling data were assessed to determine their ability to predict full-scale at sea performance of the Campelen 1800 trawl. The numerical simulation data were also compared against scale model engineering performance under identical conditions. The study demonstrates that the ideal method with which to accurately predict full-scale at-sea performance of bottom trawls or used for designing a trawling system probably does not exist. Therefore, the importance of using two or three complementary tools should be encouraged as an ideal process for designing a trawling system and/or assisting the gear development circle.

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Abstract:We developed and evaluated an innovative trawl technology that reduces seabed contact while targeting northern shrimp (Pandalus borealis) off the east coast of Canada. The innovative footgear, referred to as the "aligned footgear", was evaluated in a flume tank to estimate contact area with the seabed and then tested at sea for engineering performance and catchability. Results demonstrated that the aligned footgear trawl produced a substantial reduction (i.e., 61%) in the predicted contact area with the seabed compared with the identical trawl equipped with traditional rockhopper footgear. A total of 20 paired tows (n = 40 tows) were subsequently conducted at sea to evaluate fishing performance. The aligned footgear trawl caught significantly more northern shrimp (+23%), capelin (Mallotus villosus) (+71%), and Greenland halibut (Reinhardtius hippoglossoides) (+99%) compared with the traditional rockhopper bottom trawl.Résumé : Nous avons mis au point et évalué une technique novatrice de pêche au chalut qui réduit le contact avec le fond marin en ciblant la crevette nordique (Pandalus borealis) au large de la côte est du Canada. Le bourrelet novateur, appelé « bourrelet aligné », a été évalué dans un bassin à circulation d'eau afin d'estimer l'aire de contact avec le fond marin, puis a fait l'objet d'essais en mer pour évaluer la performance technique et la capturabilité. Les résultats démontrent que le chalut à bourrelet aligné entraîne une réduction importante (c.-à -d. 61 %) de l'aire de contact prévue avec le fond marin par rapport au même chalut équipé d'un bourrelet sauteur classique. Un total de 20 traits appariés (n = 40 traits) ont ensuite été effectués en mer afin d'évaluer la performance de pêche. Le chalut à bourrelet aligné a pris des quantités significativement plus grandes de crevettes nordiques (+23 %), capelans (Mallotus villosus) (+71 %) et flétans noirs (Reinhardtius hippoglossoides) (+99 %) que le chalut de fond à bourrelet sauteur classique. [Traduit par la Rédaction]

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