Chickenfeed (Completed)

The economics of trawl fishing along the Coromandel coast

Trawling is one of the most efficiently destructive and wasteful fishing techniques known, leading to rapid overharvests of trawled waters. Along the East Coast of India, the fishery keeps itself profitable by finding value in previously discarded trash fish, now used to feed the rapidly growing poultry industry

  • A burgeoning fleet of east coast trawlers have to fish longer and deeper to remain profitable

  • A large proportion of economically unviable fish catch gets discarded

  • Previously discarded catch are now finding new economic value as chickenfeed

  • Small crustaceans and other species, previously considered trash are now sold to feed poultry

  • Sorted trash fish ready for transport to chicken farms

Trash fishing is a thriving industry

Trawlers have gained global notoriety for the high levels of bycatch they discard. Besides being ecologically unsustainable, the discarded bycatch, is of little value to trawl fishers. However, it serves as the sole source of livelihood and protein to artisanal fishers and millions who throng the coastlines of the developing world.
However, with declining commercial fish stocks and decreasing profits, fishers  in India and other parts of the developing world, find more commercial value in ‘trash fish’ (the previously discarded category of bycatch).

In this project we sought to understand the economics of trawl fishing along the Coromandel Coast in the light of rapid overexploitation.  We monitored trawlers along the Tamil Nadu coastline, documenting operational costs, quantities and prices of target and trash fish. Our data indicate that fishers adopted different strategies, dynamically adapting to local conditions in the struggle to stay profitable. Landing trash was an important part of this strategy, and it supports a thriving industry along the Coromandel that processes trash into poultry feed and includes several middlemen, sorters and finally fishmeal processing plants. 

Our data indicate that trash fishing helps subsidize the trawl fishery, particularly when commercial catch profits are low, fuel prices increase or the catch variability is high. 

Rays of hope: indicators of trawling intensity

Trawling is a largely unmanaged fishery along the coast, driven by market imperatives, technology and resource stocks. This drives a pattern of sequential overexploitation, as benthic waters are first depleted of their large, long-lived carnivores and the fishery shifts to  species lower down the marine food web.  A recent analysis of long-term data series suggests that this trophic decline, termed "fishing down food webs" is also evident in the Indian marine fisheries sector. 

One of the principle difficulties of managing this sector in Indian waters is the notorious unreliability of direct monitoring measures of fishing intensity.  These data are logistically complex to collect, collate and make sense of.  We conducted a study to determine if it were possible to use simple proxies of overfishing along the Coromandel coast.  We explored the use of benthic elasmobranchs (essentially rays and skates) as an indicator of trawling intensity. We recorded at least 19  species (from 7 families),  exhibiting a range of life history characteristics. These species show a clear differential response along a gradient of fishing intensity. The abundances of some species decline exponentially with increasing trawling intensity. In addition, adult body lengths of individuals captured in heavily trawled areas were considerably smaller than those captured in low fishing intensity areas. Taken together our work suggests that this group may be a useful and robust indicator of trawling intensity.


Rays are highly susceptible to trawl fishing making them useful indicators of fishing intensity





  • Book Chapter
    Narrative from Indian seas: Marine resource use, Ecosystem responses, and the accidents of history.
    Pages 229-248 in G. Cederlöf and M. Rangarajan (editors), 'At Nature's Edge: The Global Present and Long-Term History,' Oxford University Press, New Delhi. 331 pp.
  • Journal Article
    Opportunistic exploitation: an overlooked pathway to extinction
    Trevor A Branch, Aaron Savio Lobo, Steven W Purcell
    Trends in Ecology and Evolution. 28(7): 409-413

    PDF, 951 KB

    How can species be exploited economically to extinction? Past single-species hypotheses examining the economic plausibility of exploiting rare species have argued that the escalating value of rarity allows extinction to be profitable. We describe an alternative pathway toward extinction in multispecies exploitation systems, termed ‘opportunistic exploitation’. In this mode, highly valued species that are targeted first by fishing, hunting, and logging become rare, but their populations can decline further through opportunistic exploitation while more common but less desirable species are targeted. Effectively, expanding exploitation to more species subsidizes the eventual extinction of valuable species at low densities. Managers need to recognize conditions that permit opportunistic depletion and pass regulations to protect highly desirable species when exploitation can expand to other species.

  • Journal Article
    Commercializing bycatch can push a fishery beyond economic extinction
    Aaron Savio Lobo, Andrew Balmford, Rohan Arthur, Andrea Manica
    Conservation Letters 3: 277-285

    PDF, 255 KB

    Tropical bottom trawling is among the most destructive fishing practices, catch- ing large quantities of bycatch, which are usually discarded. We used question- naire surveys of trawl fishers to look at changes in catches over the last 30 years (1978–2008) along India’s Coromandel Coast. We show that catches and in- come from target species have declined sharply over the last two decades. Meanwhile, costs of fishing have increased substantially and now almost ex- ceed income from target species. Over the same period, bycatch (which was traditionally discarded) has now become increasingly marketable, being sold for local consumption, and as fish meal to supply the region’s rapidly growing poultry industry. Without this income from bycatch, the fishery would scarcely be economically viable. While such a change in the use of bycatch is good news in terms of reducing waste and improving livelihoods, it is also responsible for pushing the Indian bottom trawl fishery beyond the economic extinction of its target species.

  • Journal Article
    Trawling the shorelines
    Seminar. September 2010. Nature without Borders: A symposium on innovative approaches to conserving nature and wildlife

    Fishing  in India has grown exponentially. It is an industry adapting to its own economic impulses, keeping itself afloat – quite literally – by responding to changes in supply and demand, seeking new markets, repackaging its products and by-products to woo these new markets, reinventing itself constantly in order to survive. The upshot of this industrial inventiveness is that a system of production that should have been designated unsustainable years ago, continues to persist at an increasing ecological cost. And since all of this happens beneath the waves, it largely escapes the noisy debates over the vanishing wilds.

    In this paper we present a potted history of trawl fishing along the Indian coastline, and trace its ecological and economic fallout to coastal communities, both human and marine. We discuss the factors currently driving the economics of trawling within the Indian scenario, and explore potential directions towards a more meaningful management of this harvest. Our discussion focuses on fishery off the Coromandel coast, since that is the area we are most familiar with, but it is indicative of much of the rest of the Indian coastline.

  • Report
    Strategies for reducing bycatch of susceptible species
    Aaron Savio Lobo, M Santhanakrishnan, Vidya Iyer, Rohan Arthur
    Policy Brief. UNDP/UNTRS and NCF. Chennai

    PDF, 772 KB

Did you know your internet explorer is out of date?

To access our website you should upgrade to a newer version or other web browser.

How to do that »