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Marine life mortalities and Harmful Algal Blooms in the Northern Arabian Gulf à Faiza Y. Al-Yamani, Igor Polikarpov, and Maria Saburova Ecosystem-Based Management of Marine Resources Program, Environment and Life Sciences Research Center, Kuwait Institute for Scientific Research, P.O. BOX 1638, Salmiya 22017, Kuwait à Corresponding author: [email protected] Kuwait, which is located in the northwestern Arabian Gulf, has experienced several incidences of marine life mortality during the past two decades. Mortalities included pelagic and benthic fish, Sea Cucumbers and Mollusks including pearl oysters. Most of the mortalities occurred in Kuwait Bay, which is shallow and semi-enclosed. The Bay encompasses Sulaibikhat Bay, whose coastal waters are nutrient-rich and eutrophicated due to sewage discharge into its waters. Other mortalities were reported outside Kuwait Bay, especially in marinas and southern waters of Kuwait. Kuwait’s marine environment has been increasingly affected by harmful algal blooms, which increased by frequency and severity. Other Gulf countries experienced serious mortality incidences as well. Different causes were responsible for the different marine mortalities in Kuwait and the region, including untreated sewage input, eutrophication, bacterial infection, algal blooms, hypoxic conditions, pollution, and dredging. The above mortalities impacted the economy, and affected aquaculture activities, the fishing operations, coastal tourism, damaged coral reefs, and forced the closure of desalination plants. This study summarizes the different mortality incidents that occurred in the northwestern Arabian Gulf dur- ing the period of 1999 to 2019 and their possible causes. Efforts, taken by Kuwait to improve the environmental conditions of the degraded coastal area of Kuwait Bay, include for example, the desig- nation of a marine protected area in southern Kuwait Bay that would ensure the continued production of ecological services of the protected Bay area. Keywords: fish kill, northwestern Indian Ocean, phytoplankton Introduction of 239,000 km2, with a total volume of 7000- 8400 km3 (Emery, 1956; Purser and Seibold, The Arabian Gulf (referred to here as the Gulf), 1973; El-Gindy and Hegazi, 1996; Kampf and which is also referred to as the Persian Gulf or Sadrinasab, 2006). The Gulf is a marginal sea in Inner Sea of the ROPME Sea Area, is an arm of an arid zone, with a sub-tropical climate, mostly the Indian Ocean. It is a relatively shallow sea surrounded by deserts. It has an average rainfall of with a mean water depth of 35 m, with depths < 5 cm in coastal Arabia (Al-Yamani et al., 2004). exceeding 100 m occurring only at the Strait of The main freshwater inflow is from the Shatt Al- Hormuz. Extensive shallow regions < 20 m deep, Arab River, which forms at Qurna where the are found off the coasts of Kuwait, Bahrain, and Tigris and Euphrates Rivers join together and is the United Arab Emirates. The Gulf covers an area joined downward by the Karun River before it 196 Aquatic Ecosystem Health & Management, 23(2):196–209, 2020. Copyright # 2020 AEHMS. ISSN: 1463-4988 print / 1539-4077 online DOI: 10.1080/14634988.2020.1798157 Downloaded from http://read.dukeupress.edu/aehm/article-pdf/23/2/196/899272/196al-yamani.pdf by guest on 29 September 2021 Al-Yamani et al. / Aquatic Ecosystem Health and Management 23 (2020) 196–209 197 discharges into the northern Gulf (Al-Muhyi, industry, and overfishing) and their impacts on 2015). The mean surface salinity of the Gulf is the Gulf’s marine systems. about 41 psu. High salinities of the Gulf are due to This study summarizes a range of incidents of high evaporation rates, which exceed the sum of marine biota mortality in the northwestern Gulf precipitation with an annual mean of 34 km3 and since the first fish kill reported in Kuwait’s river discharge with an annual mean of 37 km3 waters in 1999 to date, and their possible causes. (Al-Yamani et al., 2004; Sheppard et al., 2010). Mean evaporative water losses are estimated to be about 326 km3 per year (Sheppard et al., 2010). Marine life mortality incidences The Gulf is connected to the Sea of Oman and the in the northwestern Gulf (a case Arabian Sea through the Strait of Hormuz, where study in Kuwait’s waters) water exchange between the Gulf and the Sea of Oman occurs. More water of about 3365 km3 Kuwait’s waters in the northwestern Gulf are À year 1 flows into the Gulf than exits the Gulf shallow with a maximum depth of about 30 m, À (3110 km3 year 1) through the Strait of Hormuz well-mixed, and biologically rich. The seawater (Ackleson et al., 1992). temperature ranges from 10 Cto36C, and has a The general circulation of the Gulf is counter- mean salinity of 42 psu (Al-Yamani et al., 2004). clockwise, and is mainly driven by halocline However, surface salinity varies in Kuwait’s forces caused by the high evaporation rates waters due to the seasonal and interannual fluctua- (Reynolds, 1993). The northwesterly or “shamal” tions in the discharge volume of Shatt Al-Arab wind plays an important role in the large-scale cir- (Al-Yamani et al., 2004; Al-Said et al. 2019), culation of the Gulf (Perrone, 1979), and influence which is attributed to human intervention in river- the coastal currents and storm surges, especially, ine flow upstream (Al-Yamani et al., 2017). in the southern basin (Cavalcante et al., 2016). Almost all of Kuwait’s coasts have been modi- In recent years, the marine environment of the fied, except part of the northern coast of Kuwait Gulf has been the focus of many studies, dealing Bay. Legal and illegal structures (>850 structures with its oceanographic characteristics, ecology, including boat ramps, small harbors, piers, jetties, biodiversity, biogeochemical processes, fisheries retaining walls and wave breakers, among others) and the impacts of natural as well as anthropogenic exist on Kuwait’s coast (Al-Mutairi et al., 2014; activities on its ecology and productivity (Hamza Devlin et al., 2015). Along Kuwait’s shores, hun- and Munawar, 2009; Nezlin et al., 2010; Sheppard dreds of hectares of land have been reclaimed and et al., 2010; Al-Yamani et al., 2012, 2017; dredged; however, even with these modifications, Polikarpov et al., 2016; Al-Said et al. 2019; Al- Kuwait’s coastal zone remains a productive com- Yamani and Naqvi, 2019; Devlin et al., 2019). ponent of the marine ecosystem (Al-Yamani et al., The extreme conditions of the Gulf, especially 2004; Sheppard et al., 2010). Probably, some of with regard to temperatures and the impact on the the artificial structures, such as marinas, can play a marine fauna, is driving a growing interest in positive role for marine life by increasing of diver- conducting studies with a focus on the potential sification of underwater coastal landscapes, pro- impact of climate change on the Gulf’s marine viding shelters and food for early life stages and environment and its biota (Burt et al., 2014; hard substrates for sessile marine organisms, Vaughan and Burt, 2016; Ben-Hassan and including bio-filtrators, such as sponges. Christensen, 2019). Kuwait has experienced several incidences of An up-to-date review of the current status of marine mortalities (Fig. 1), the causes of which are the Gulf’s marine environment and ecosystems, numerous and sometimes overlapping. Examples the threats to these valuable ecosystems, as well of the causes for the localized die-off of fish and as management efforts to rehabilitate and con- invertebrate populations are natural causes such as serve them is provided by Vaughan et al. (2018). hypoxia, as well as other causes such as infectious They addressed the subject of climate change as diseases and parasites, eutrophication and reduc- well as the different anthropogenic activities (e.g. tion in water quality (due to sewage discharges, coastal development, wastewater discharge, agricultural runoff, oil or hazardous waste spills), desalination plants, shipping traffic, petroleum reduced oxygen concentration in the water column Downloaded from http://read.dukeupress.edu/aehm/article-pdf/23/2/196/899272/196al-yamani.pdf by guest on 29 September 2021 198 Al-Yamani et al. / Aquatic Ecosystem Health and Management 23 (2020) 196–209 and bottom, harmful and toxic algal blooms, 2002). Whether this dinoflagellate species was dredging affecting bottom biota, as well as some- ichthyotoxic or that the fish died from secondary times ‘unknown’ causes. The hypoxic event may harmful effects associated with that bloom still be brought on by factors such as algal blooms, remains uncertain, but it was decided that high temperatures, and thermal pollution. eutrophication of Kuwait Bay caused by elevated Fish kills associated with desalination plants nutrients, potentially from aquaculture activities due to thermal pollution and high concentration as well as industrial and untreated sewage inputs, of free chlorine were reported in 1995, 1996, could have caused the initiation and maintenance 1997 and 1998 in Kuwait. Fish mortality was of the Karenia bloom, which lead to fish mortal- also related to oil spill from the tanker in Kuwaiti ity in Kuwait Bay (Heil et al., 2001). waters in 1996 (Al-Yamani et al., 2000). Later, several other factors have been reported as rea- 2001 fish mortality associated sons for marine mortalities in Kuwait’s waters (Al-Yamani et al., 2012). The assessment of with bacterial infection long-term records of marine mortality in In August and September 2001, Kuwait Bay Kuwait’s waters is a challenge since, apart from experienced a massive kill of wild Klunzinger’s the two well-documented fish kill reports in 1999 mullet Liza klunzingeri that resulted in over 2,500 and 2001 in peer reviewed literature (Heil et al., tons of dead fish (Glibert et al., 2002). This event 2001; Glibert et al., 2002), published details are was nearly 100-fold larger than the previous major very sparse and not sufficiently documented.

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