Turtle Exclusion Devices

The U.K. alone has 6,400 fishing vessels, with total landings of fish catch equating to $1.3 billion (627,000 tons) in 2012 (1). Despite warnings of a slowdown in the marine catch in the 1970s and 80s, the fishing industry increased fishing efforts with more powerful boats as well as superior technology, allowing the tracking of fish populations with sonar devices and larger nets to increase catch size. In addition, the international commercial fishing industry is double the size necessary to meet current requirements, and overcapacity is now a global norm. The European Union itself is in 40% overcapacity, resulting in fierce competition and difficulties in mitigating impacts with higher percentages found around the globe (2).

The Problem
Although overexploitation of fishing resources is the main issue, wasteful practices which resort in by-catch or discard is an area necessitating much focus by resource management schemes. By-catch has long been recognized as a widespread issue, with around 25% of total catch being discarded back into the sea dead due to little or no commercial value (3). This equates to approximately 27 million tons, the equivalent of 600 fully-laden Titanics (4).
The impact of by-catch to the ocean ecosystems is not only colossal but often irreversible (5). The different types of commercial fishing practices result in variations of species and quantities being killed as by-catch: nets kill cetaceans, long-line fishing kills birds and bottom trawling devastates marine ecosystems (5).
oShrimp fisheries are renowned to be inefficient and ecologically damaging, with often more than 80% of a catch comprising marine species other than shrimp which gets discarded (5). Bottom-trawling and beam-trawling, removes up to 20% of the seafloor fauna and flora in a single trawl, in addition to by-catch of commercially unattractive animals (5).
By-catch occurs due to fishing gears inability to adequately select target species, the problem worsened by economic pressures resulting from overexploitation (3). A large majority of by-catch is discarded due to fishing quotas minimizing landings (size of catch) and when regulatory restrictions prohibit retention of particular attributes (size, species, sex) (3, 5). Therefore, some by-catch occurs in commercial fisheries, however, higher rates are found in fisheries with less selective fishing methods and practices.  Mitigating the environmental impact of commercial fishing by avoiding, minimizing and compensating for adverse effects, is fundamental for fisheries management authorities worldwide (6). The complex interplay of ecological, economic, and social considerations has often resulted in by-catch management being reactive, confrontational and costly (6). Some by-catch species, including fish, reptiles, birds and mammals, may be threatened with extinction (3). Even Tuna fisheries, which in the past had high dolphin by-catch levels, are still responsible for the deaths of an estimated one million sharks annually (5). Around the U.K., evidence of the growing scale of by-catch is washed up on beaches around the south west of England and northern France annually in the form of dolphin and porpoise corpses.
Progresses in technology for impact reduction has not been as quickly established as technologies designed to increase overall catch. Although modifications to fishing gear or practices have offered an effective means of reducing by-catch, such as turtle exclusion devices and Pingers, these devices need continual monitoring and in many cases it has been difficult to demonstrate success (3, 6). Therefore effective use of these devices depends on overcoming gear handling constraints and the short-term economic losses often associated with their use (3).

The Solution
The Icelandic high technology company Star-Oddi has developed revolutionary equipment that filters out the majority of unwanted by-catch, (up to 75% of the by-catch). The Fish Selector, which is an equipment that automatically separates the fish while still in the trawl, means that discarding of fish by fishing companies could be a thing of the past.
The aims of using Fish Selector are to increase the value of the catch, avoid discard of fish and increase fishing efficiency by helping with decision making for the skipper of selecting a fishing area. In addition to benefitting the commercial fisheries companies the marine research institutes may find scientific value in using the equipment in their studies.
The Fish Selector is placed in front of the cod-end and as the fish swim through the device it is pre-programmed to select fish by specific size and species so those that are not intended for landing, are sorted out and directed away through a bypass gate. Collected information is wirelessly monitored in real-time in the bridge on the quantity of fish caught, as well as quantity bypassed. Other data can be collected such as depth, temperature and inclination.
Data on how many fish are caught and how many are released is automatically stored and sent in real time onboard the vessel. Collected information on quantity of caught fish and bypassed fish can be viewed wirelessly by the crew. The data gives insight into the quality of the fishing ground so the skipper can quickly and better estimate if fishing should continue or if movement to a different area would be beneficial. The emphasis on responsible and sustainable fisheries has been increasing. Fishing companies using the Fish Selector can help in delivering the message to consumers that the company is making its contribution to sustainable fisheries by releasing threatened species.

Field Testing
In December 2010 the Fish Selector was tested on the research ship Drofn. It operated very well on its first sea trial. Since then, focus has been on reducing the size of the equipment which will give the fishermen the following advantages:
Takes less deck space
Smaller volume and weight decreases hazards associated with having bulky equipment on deck
Fishermen can more easily move the equipment around and the smaller device is then carried by two operatives
Smaller volume and lower weight will make it easier to take the device onto smaller ships, increasing the market potential
 

First Prize Innovation Award for the Fish Selector
Star-Oddi won first prize for the most innovative technology for the fishing industry at the Icelandic Fisheries Conference. The conference was held for the fourth time in November 2013. People from fishing companies, state officials and scientists attend this conference. The goal of the award is to encourage creative thinking and innovation in the fisheries sector.


About Star-Oddi
Star-Oddi (Iceland) develops research equipment for increasing the knowledge on marine life and underwater environments. Star-Oddi specializes in the design and manufacture of scientific equipment, mainly miniature data loggers containing microelectronics and sensors for monitoring behavioral and environmental parameters such as salinity, temperature, depth, tilt angle and more. The miniature self-contained loggers are used for behavioural studies of fish as well as on moorings and nets.
 

References

(1) Overview of the UK fishing Industry (2013). Retrieved from Marine Management Organization website: www.marinemanagement.org.uk/fisheries/statistics/annual.htm

(2) World Fisheries: Declines, Potential and Human Reliance (April, 2006). Retrieved from the University of Michigan website: www.globalchange.umich.edu/globalchange2/current/lectures/fisheries/fisheries.html

(3) Cook, R. (2003). The Magnitude and Impact of By-catch Mortality by Fishing Gear. In M. Sinclair & G. Valdimarsson (Eds.), FAO. Responsible Fisheries in the Marine Ecosystem.

(4) Threat 1: Overfishing (n.d.). Retrieved from Save Our Seas Foundation website: saveourseas.com/threats/overfishing

(5) Bycatch – wasteful and destructive fishing (n.d.). Retrieved from Greenpeace website: www.greenpeace.org.uk/oceans/problems/bycatch-wasteful-and-destructive-fishing

(6) Kirby, S.K., Ward, P. (2014). Standards for the effective management of fisheries bycatch. Marine Policy, 44, 419-426

 

(As published in the May 2014 edition of Marine Technology Reporter - http://www.marinetechnologynews.com/Magazine)