Aquaculture in coastal urbanized areas: A comparative review of the challenges posed by Harmful Algal Blooms

Abstract

Increasing global population has resulted in increased urbanization of coastal areas across the globe. Such an increase generates many challenges for sustainable food production and food security. The development of aquaculture has proven to be an extremely good option to ensure food security (uninterrupted supply and good quality of food) by many countries, especially those with urban areas affected by space limitations such as Singapore. However, the implementation of aquaculture is not without its challenges and impacts to the environment, with Harmful Algal Blooms (HABs) being one of the major concerns in coastal waters. In this review we analyze the development of the aquaculture industry with respect to HABs in Singapore and compare it to similar urban areas such as Hong Kong (SAR China), Salalah (Oman), Cape Town (South Africa), Valencia (Spain), Rotterdam (The Netherlands), Tampa bay (USA), Vancouver (Canada), and Sydney (Australia). Along with HABs, the abovementioned urban areas face different challenges in sustainably increasing their aquaculture production with respect to the economy and geography. This review further assesses the different production and monitoring strategies that have been implemented to counter these challenges while sustainably increasing production. The ongoing COVID-19 pandemic has affected the world with lockdowns and border closures resulting in logistical difficulties in seafood trade which has further accentuated the dependencies on food import. We conclude that the challenges faced by urban areas for sustainable achievement of food security through development of the aquaculture industry can be effectively managed through proper planning, management and collaboration of knowledge/skills on an international level.

Aqua medicines, drugs and chemicals (AMDC) used in freshwater aquaculture of South-Eastern Bangladesh

“…A large number of algal blooms occur in aquaculture ponds, and they are frequently catastrophic. In fish ponds, nutrient enrichment caused by the addition of fertilizers and additional feeding results in eutrophication, which is characterized by the development of thick algal blooms on a regular basis (Padmavathi and Prasad, 2007;Rodgers, 2008;Trottet et al, 2021). Removing the phytoplankton bloom is one of the challenges in aquaculture setup due to it works as primary producers in the pond.…”

Anthropogenic Modifications to Estuaries Facilitate the Invasion of Non-Native Species

“…Thus, it should involve a "worst case scenario" that could occur in real water conditions [18,73]. Additionally, the development of efficient ballast water management systems in these scenarios would also benefit some related industries, such as aquaculture, which is also, potentially, affected by possible spread of organisms resulting from an inadequate ballast water management [61,70].…”

“…Global warming has a direct effect on the proliferation of harmful algal blooms (HABs), which may also be promoted because of the contents of ballast water. These are of particular interest and concern because of their economic and health consequences [70]. Most of the related studies have been focused on the role of global warming in freshwater cyanobacterial invasion patterns [71]; however, further research is encouraged concerning marine HABs and the role of global warming in their spread.…”

Do Ballast Water Management Systems Reduce Phytoplankton Introductions to Canadian Waters?

“…Several phytoplankton species transported in ballast water are able to survive the voyage (Casas-Monroy et al, 2016), facilitated by life history characteristics such as mixotrophy and resting stage formation (Taylor et al, 2008), and may establish self-sustaining populations after release in new areas (Hallegraeff, 1998). Several phytoplankton species are harmful or toxic, and have been associated with ship-mediated introductions in different countries [e.g., Australia: Hallegraeff and Bolch (1992); Great Britain: Hamer et al (2001)], sometimes with dramatic ecological and economic consequences, particularly for aquaculture farmers (Trottet et al, 2021). In North America, commercial ships have been implicated in the dispersal of the brown tide Aureococcus anophagefferens Hargraves et Sieburth, into the Great Lakes (Doblin et al, 2004).…”