Shark Fisheries
Shark Fishing © Marcia Moreno Baez, Marine Photobank.

At present, concerns are growing with regard to the impact of fishing upon shark populations and are currently being raised at an international level. The depletion and collapse of many fish stocks and elasmobranchs has resulted in increased media attention and focus upon marine conservation.

The species survival commission of the IUCN has developed a dedicated unit, the Shark Specialist Group (SSG), which is preparing a global action plan for the conservation and management of sharks. The parties to the Convention on International Trade in Endangered Species of wild flora and fauna (CITES) took unprecedented action in 1994 by mandating a review of the status and trade in sharks, a group at the time that was not currently listed on the cites appendices. In addition the Food and Agriculture Organisation (FAO) also has dedicated a technical working group dedicated to shark conservation.

There are several reasons why sharks and other elasmobranchs have grown to such a concern, one of which is their K-selective life history characteristics, meaning they are characterised by slow growth, late attainment of sexual maturity, long life spans, low fecundity and a low natural mortality, making this group of species particularly vulnerable to exploitation. Once overfished shark populations could take decades to recover, the extremely poor record of sustainability of target shark fisheries provides evidence of how little these vulnerable species can cope with exploitation. Many of the countries that target shark fisheries have little or no management strategies in place.

There is growing concern about the population status of top predatory fishes and the impact that reduced predator abundance could have on marine ecosystems. From the dramatic decline in many commercial fish species to fisheries collapsing in their entirety, we have come to realise that our marine ecosystems have been significantly impacted. This is especially relevant with regards to tuna and billfish populations, one meta-analytical estimates indicated that the current biomass of these large predatory fish is less than 10% of historic levels in the world’s oceans. In light of this, research and interest has been directed towards shark populations, in particular the levels of catch and sustainability. Unfortunately, as the majority of shark landings are caught through bycatch, the data usually goes unrecorded. Due to these data implications, mostly consisting of gaps within data series and the unprecedented amount of unreported data with regards to bycatch and illegal trade, reliable quantitative assessment of shark populations has been a difficult subject to tackle. High seas fleets from areas such as Japan, Korea, Taiwan and Russia are particularly devastating, as there is no requirement to record. Therefore the magnitude and mortality of sharks caught within these fisheries is not reflected within catch statistics recorded.

This bycatch of vulnerable species can occur when using a range of fishing methods and practices. The harvesting of aquatic resources can be carried out using a wide range of technologies, from artisanal to highly industrial. The technological development and widespread use of hydraulic equipment for gear and fish handling, electronics for fish finding, satellite based technology for navigation and communications have all led to the expansion of fisheries in recent decades. Technical advances have generally led to more efficient and economical fishing operations, reduction in physical labour per unit of output and improved access to resources. Where management of these practices is inefficient of lacking, such as those on the high seas has led to overfishing and environmental degradation. As a result, there is a greater need to develop more effective fisheries management frameworks, together with more environmentally friendly fishing methods, for example developing selective fishing gear to reduce bycatch of vulnerable species such as that of sharks.