By Stephanie Liefmann
As a benthic biologist sometimes I do feel pelagic. As I finish my PhD on deep sea corals I cannot avoid but thinking on the long path that food items have to travel before they reach the sea-floor, and all the amazing creatures they meet. Lately, my thoughts have been on sharks, perhaps because the last few months I have been living with a two year old toddler who is obsessed with “Baby Shark”, or just because of their majestic and imposing beauty. Benthic sharks do also exists, so perhaps I am not feeling that pelagic after all.
Ranging from shallow coral reefs down to the depths of the ocean, the apex predators of our seas are being overexploited. According to the IUCN Red List 30% of all sharks and rays are threatened with extinction.
Threats that sharks face include bycatch (Clarke et al.,2016 ), direct consumption in the meat or fin trade, and products for the beauty industry (Dent and Clarke, 2015). The industry that has received the most press attention is the fin trade industry, because it shockingly leaves the finless bodies to sink and slowly die. Unfortunately shark finning is very difficult to control and is often illegally performed close to natural reserves such as the Galapagos Islands and the Malpelo Island in the tropical Pacific Ocean.
Studies showing the decrease in shark abundances are numerous both from coastal environments and open waters (Dulvy et al., 2014; Roff et al., 2018), the cascading effects due to lack of top down control, meaning nobody is there to control the populations of other animals, are also acknowledged by the scientific community (Myers et al., 2007). Sadly, managing shark exploitation be it intentional or unintentional can be difficult. For example, sharks have extensive ranges, or are migratory species, thus closing areas to fishing might not represent a very effective strategy, unless the closed area constitutes a very large geographical range (MacNeil et al., 2020). Regulation of fishing gear might be a better option, since it could effectively reduce shark bycatch. Nevertheless as explained by Mcneil et al. (2020) these methods will most likely work in areas where sharks are not actively targeted, such as bycatch.
As the demand for shark products increases, and given the current state of our world economy the socio-economic problems, and the inherent greed of the human race, there will always be somebody willing to procure the wanted illegal goods. The gloom in the last sentence might seem overwhelming, but socio-economic problems should not be taken lightly where the government and social policies are lacking, people often have to resort to illegal practices in order to survive. For example fishermen in small villages of Indonesia, started fin fishing because the prices of the product was higher than other catches (Jaieth et al., 2017). Regulations for targeted shark fisheries do exist in “poor” countries, the problem lies on the lack of governance to implement those policies, and enforce the recommended quotas.
In order to more effectively protect our beloved apex predators, socio economic problems should be addressed in management strategies, which should include capacity building to offer an alternative livelihood to communities that are dependent on the income brought by shark fishing, for example well managed ecotourism. Approaches to implement such holistic methods have already been proposed by the scientific community (Booth et al., 2019), the authors proposed management strategies encompassing biological knowledge of the different shark species, technical solutions to reduce bycatch, understanding the economical drivers of the trade and imposing bans and regulating markets, and last but not least, taking into account constraints of the broader regulatory, cultural and economic conditions of a fishery and the fishermen.
To finish on a less gloomy note, I would like to mention that the scientific community all over the world has been working tirelessly. Several organizations have been created throughout the years in different parts of the world in order to fight the battle that sharks and other elasmobranchs cannot. I will leave you with some of my favourites. Off course 3 of them are from Colombia, my home country. Colombia Scientist of the “Colombia azul” foundation, have developed a tool to quickly identify Shark DNA to help customs official around the globe to monitor illegal shark trade (Cardeñosa et al., 2017). The Malpelo foundation, aims to educate the population through capacity building and outreach, and helps the Colombian authorities to protect the fauna of the Malpelo natural reserve, which harbours big aggregation of scallop hammerhead sharks. The Squalus Foundation who run scientific endeavours in order to gather information for the preservation and conservation of elasmobranchs throughout South America. In Mexico, the foundation Pelagios Kakunjá whose goal is to study and protect sharks and mantas and provide technical information for the regional management and implementation of conservation strategies.
Booth, H., Squires, D., & Milner-Gulland, E. J. (2019). The neglected complexities of shark fisheries, and priorities for holistic risk-based management. Ocean & Coastal Management, 182, 104994.
Cardeñosa, D., Fields, A., Abercrombie, D., Feldheim, K., Shea, S. K., & Chapman, D. D. (2017). A multiplex PCR mini-barcode assay to identify processed shark products in the global trade. PloS one, 12(10), e0185368.
Clarke, T. M., Espinoza, M., Ahrens, R., & Wehrtmann, I. S. (2016). Elasmobranch bycatch associated with the shrimp trawl fishery off the Pacific coast of Costa Rica, Central America. Fishery Bulletin, 114(1).
Dent, F., & Clarke, S. (2015). State of the global market for shark products. FAO Fisheries and Aquaculture technical paper, (590), I.
Dulvy, N. K., Fowler, S. L., Musick, J. A., Cavanagh, R. D., Kyne, P. M., Harrison, L. R., … & Pollock, C. M. (2014). Extinction risk and conservation of the world’s sharks and rays. elife, 3, e00590.
Jaiteh, V. F., Loneragan, N. R., & Warren, C. (2017). The end of shark finning? Impacts of declining catches and fin demand on coastal community livelihoods. Marine Policy, 82, 224-233.
MacNeil, M. A., Chapman, D. D., Heupel, M., Simpfendorfer, C. A., Heithaus, M., Meekan, M., … & Currey-Randall, L. M. (2020). Global status and conservation potential of reef sharks. Nature, 1-6.
Myers, R. A., Baum, J. K., Shepherd, T. D., Powers, S. P., & Peterson, C. H. (2007). Cascading effects of the loss of apex predatory sharks from a coastal ocean. Science, 315(5820), 1846-1850.
Roff, G., Brown, C. J., Priest, M. A., & Mumby, P. J. (2018). Decline of coastal apex shark populations over the past half century. Communications biology, 1(1), 1-11.