There are many factors that may compromise fish abundance. Some, like the effects of raising temperature, acidification, algal blooms or changing currents can be difficult to predict and act upon. But illegal fishing is one cause of stock depletion that can be addressed and controlled.
Our grossly oversized global fishing fleets are engaged in a fierce effort to capture their share of a decreasing volume of fish stocks. This level of competition, plus a lack of effective fishing vessel controls encourage illegal fishing, organised transnational fisheries crime and cross-over criminal activities.
Like other types of unlawful maritime activity, illegal fishing takes place with more frequency and intensity in coastal maritime regions that governments are less able to monitor, access and control. In these areas, legitimate economic activities have little official protection against the threat of abuse and crime.
Large industrial vessels can illegally harvest vast quantities of fish that subsistence fisherfolk in vulnerable areas depend on. Local official corruption frequently results in the illegal operators being protected and encouraged to act again. Given the efficiency of modern fishing vessels, protracted predatory incursions into the traditional fishing grounds of others may cause enduring fish depletion.
The collapse of fish stocks and ensuing marine environmental degradation are good reasons to put illegal fishing control high on governments agendas. However, recent research by Markus Ludwig and Matthias Fluckiger, of the University of Basel, has highlighted an additional, compelling reason why illegal fishing should be stopped: Piracy.
Narratives linking foreign illegal fishing as a driver for piracy are not new (see, for example, the work of Bueger on Somali piracy as a form of fisheries vigilantism in Somalia).
However, the Basel University study is novel, taking a wide snapshot of data from 109 coastal countries on the strength of an original, objective methodology to draw its conclusion: That a significant decrease in fish catches can encourage piracy in fishing communities.
The study found that a 1% increase in fish catches can result in a decrease in piracy activity by 1%. The researchers point out that detected increases in piracy activity are likely to be a reaction to the temporary lack in available legitimate income opportunities, rather than a willingness to engage in lifelong criminal careers.
According to the study, the effect of negative fishery productivity changes can be far-reaching, given the detrimental effect that piracy can have on maritime economic activities like transport and other trade.
The logical conclusion is that combatting illegal fishing and prioritising policy measures to discourage it including the prosecution of those involved in fisheries illegality and crime may also be seen as tool to reducing incentives for piracy.
For access to the paper by Ludwig and Fluckiger, see http://mpra.ub.uni-muenchen.de/56959 .
 For more information on this topic, see Interpol’s Project Scale http://www.interpol.int/Crime-areas/Environmental-crime/Resources .
 For a recently reported example, see the case of the Fiji tuna fisheries http://www.undercurrentnews.com/2014/01/20/fiji-tuna-groups-cut-down-fleet-as-industry-faces-total-collapse/ .