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Is there such a thing as an ‘Ideal’ Fishing Gear?

May 8, 2013

Here’s an excerpt from a report that describes an effort by an ICES working group to find the ideal fishing gear. It comes from “Best Practices for Managing, Measuring and Mitigating the Benthic Impacts of Fishing”, a report prepared for the Marine Stewardship Council.

I think the examination of gears’ strengths and weakenesses is quite important, though fishery specific factors will always play a key role in enhancing or mitigating them. Thus, a useful exercise but context still maters a lot. (Just see my last post for food for thought.)

I highly recommend readers take a look at Figures 5 and 6. They are good visualizations of the strong relationship between environmental sustainability and catch controllability – defined largely by catch selectivity – and the weak relationship between enviromental sustainability and operational functionality, which is more important for the safety and income of the fishing operation. (At last! The challenge of getting fishermen to accept sustainable fishing practices is revealed! j/k)

Given the amount of text, I will not format the text to show it as quoted text. It appears after the break. All bolding is my own.

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One approach to conduct a qualitative assessment of different gears types with the aim of identifying “responsible fishing methods”, with respect to a number of “ideal gear properties” has been defined by the ICES Working Group on Fishing Technology and Fish Behaviour (ICES, 2006a). A range of capture methods were considered, including: beam trawling, bottom trawling, Danish (Scottish) seining, diving, dredging, drift nets, gillnets, jigging, long-lines, pelagic trawling, pole and line, purse seining, pots, trammel nets and traps.

The ideal gear properties were considered to be definitive of three key areas of impact, with respect to “responsible fishing”, and were grouped accordingly: Controllability of Catch, Environmental Sustainability and Operational Functionality (Table 2). Each capture method was scored with respect to each “ideal property” and then a simple index (index = mean score) was defined, with respect to each of the key impact areas (Table 3). To visualize the relationship between the three impact areas, for different capture methods, the indices were plotted in Figure 5, Figure 6 and Figure 7.

Please note, none of the indices described account for the relative catch efficiency (i.e. catch per unit effort) of the different capture methods. This omission is deliberate and was necessary for the following reasons. The catch efficiency of a particular capture method is fishery specific; i.e. it is highly dependent on the target species, location of the fishery, prevailing environment conditions, among other factors. Furthermore, it was generally accepted that most commercial fisheries will have evolved to use the most efficient capture method available to them. Therefore, most “alternatives” are likely to be less efficient than the current capture method. So, it was not practical, nor particularly informative, to assign an efficiency score in this qualitative overview.

It has to be stressed that this exercise is a generic approach, too general for evaluating specific fisheries.

In general, it was the opinion of the ICES Topic Group members that no single capture method could be described as “an ideal gear”. Different fisheries and management strategies will of course prioritize each of the “ideal gear properties” differently and will therefore have different requirements of a responsible fishing method. But when considering each of the properties equally, three capture methods were prominent as potentially responsible techniques:

  • Diving – This technique was considered to be the most environmentally sustainable method, with the greatest control of the catch. However, its application in a commercial fishery is very restricted. It is a highly specialised technique that is limited by working depth (<50m using air), which would make it almost impossible to apply to most commercial fisheries.
  • Pole and line – This technique also scored highly for environmental sustainability and catch control. Moreover, along with jigging, it was thought to have the greatest operational functionality: having low investment costs, usable in most habitats and relatively user safe. However as a practical capture method, it is generally limited to larger, and mostly predatory, fish species (which of itself is potentially damaging to large, less fecund species).
  • Pots – This technique was also considered to have a minimal impact upon the environment; apart from the potential for ghost fishing, which can be mitigated for with inbuilt bio-degradability of pots and gear recovery schemes. The moderate score for catch controllability was primarily due to the poor size selectivity of current gears, which again could be improved with minor design changes. However, in terms of application as an alternative gear pots score highly. They can be used relatively safely in most habitats, with only moderate investment in terms of gear costs and training.

Finally, the scores given here are the consensus opinion of the members of the ICES WGFTFB Topic Group on Alternative Fishing Gears. As such, the results of this exercise should not be considered definitive, but a useful tool for considering those properties that may be important with respect to the ideal responsible fishing method. Moreover, this approach, with a wider and more thorough application with respect to input “opinions”, could prove to be a useful management tool when considering the introduction of “alternative” capture methods to commercial fisheries.

Table 2

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