Ecological search and comparison with other coral reef regions
The eight principal topics were selected to represent current interest of coral reef research as implemented in Berumen et al. (2013) and later utilized in Reimer et al. (2019). Note that in Berumen et al. (2013), the paper (focus on Red Sea) discusses the state of knowledge of each principal topics while in Reimer et al. (2019), the paper (focus on Ryukyu Islands) highlights significant scarcity of some topics. Both studies intended to quantify the relative magnitude of work in region of interest. Hence, this study (sensu Berumen et al., 2013; Reimer et al., 2019) introduces Malaysia as region of interest into the scene and intends to give an update to the review framework.
The Web of Science (WoS) search on ecological topics found Malaysia lagged in coral reef-related research as compared to major coral reef regions such as GBR, RES, CAR and RYS. On average across the topics investigated (Table 1), Malaysia accounted for less than 5% of the total number of papers published among five regions: especially for the principal ecological topic such as reef-associated bacteria (13/909), Coral Bleaching (15/1752) recording a magnitude of low publication for most of the principal topics (five out of eight). Moreover, most principal ecology topics conducted in Malaysia were first published only after the 2000s (Fig. 2). This require future attention, as Malaysia is in the Coral Triangle area, which would present a lot of resources and research opportunities for researchers within corresponding field to contribute in marine research (Hoeksema, 2007; Veron et al., 2011).
The scientific publications focusing on coral reefs have generally exhibited an increasing trend in terms of both quantity and rate of publication over the years (Bornmann & Mutz, 2015; Reimer et al., 2019). Analysing the publication rates of various regions on ecological topics from 1971 to 2021, it becomes evident that all regions have shown consistent progress in their publication rates, particularly since the 1990s. Notably, when considering the ecological topics, Malaysia has made significant contributions in research related to Marine Protected Areas (MPAs), surpassing even the RYS region. This observation aligns with the findings discussed in Reimer et al. (2019), which indicated that RYS has relatively limited literature particularly MPAs, Apex predators, and Herbivory. The prominence of Malaysia’s research on MPAs underscores the country’s focus on this aspect of coral reef conservation and management.
Based on the WoS search, MPA is the most studied principal topic in Malaysia (Table 1; Fig. 2). The establishment of marine protected areas (MPAs) in many countries. including Malaysia serve primarily to conserve marine ecosystems as a baseline effort in sustaining coastal management (White et al., 2014). Being a member parties of the Coral Triangle Initiative (CTI), the implementation of MPAs in Malaysia are endorsed by the Coral Triangle Initiative on Coral Reefs, Fisheries and Food Security (CTI-CFF) Regional Plan of Action (RPOA) (Coral Triangle Secretariat, 2009). One of the five goals of the RPOA is to improve effective management of MPAs. Besides, the country also pledged in managing and maintaining MPAs with the efforts of active governmental institutions namely: the Division of Marine Park (previously known as the Department of Marine Park Malaysia) (Fidelman et al., 2014; Safuan et al., 2021), Sarawak Forestry and Sabah Parks (Board of Trustees of Sabah Parks, 2010; Weeks et al. 2014). The relatively concentrated MPA research focus in the country lays a good foundation for fundamental knowledge in improving MPAs management effectiveness. The condition of MPAs in the country, as discussed in White et al. (2014) are considered under control, but there are no quantitative measure or monitoring system for management evaluation. Hence, future MPA research should focus on improving effectiveness of MPAs management that take design, evaluation system, and socioeconomic factors into consideration.
Coral Reproduction is the least studied principal topic in Malaysia (0.82%). Even though most regions recorded this topic as one of their least published (CAR = 3.35%; GB = 5.15%; RES = 4.83%; RYS = 7.41%), the ratio was much more substantial than in Malaysia (Table 2). The relatively low publication number on this topic in all the regions indicate a gap in coral reproduction knowledge. Coral reproduction poses several challenges for researchers to study as it consumes both time and labour intensively as coral reproduction is (1) seasonal dependent, (2) required in situ spawning observations, and (3) environmental sensitive (Gilmour et al., 2016). For Malaysia, it is the same that many aspects of coral reproduction remain poorly studied and the interest in this topic was only started on 2014 by local researchers (Chelliah et al. 2015) and gained momentum with studies undertaken by Tan et al. (2020) and Gan et al. (2021). However, all three papers were not included in this WoS search because all of the papers used the word “spawning” but not “reproduction”. While preliminary studies provided the opportunity to improve on this topic, more experts can be nurtured to spearhead this research. Furthermore, using guidelines from the global studies (e.g., Gilmore et al., 2016), improvements in coral reproduction research should involve sequential sampling of colonies using a combination of complementary methods to counter the challenges in studying this particular topic. With this, the foundation for coral reproduction studies in the country for future research can be established and more resources should be allocated for the studies.
Porifera, or commonly known as sponges, are a group of sessile aquatic animals that are found in almost all benthic habitats (Degnan et al., 2015). The research on Porifera often involves the studies of their biological physiology, ecological interaction, taxonomy classification and even pharmaceutical properties (Van Soest et al., 2012). The results (Table 1) show an obvious contrast between Malaysian publication number (9 articles) on this topic compared to other regions especially CAR (1195 article). In the review (Van Soest, 2012) on global diversity of Sponges found that the distributions appear to show a strong bias towards collection and taxonomy efforts. Regions with low reported diversity may be due to limited research exploration, which is the case for tropical coral reef regions reputedly for the most marine biodiversity richness areas. Hence, there is clearly a need for Malaysian researchers to increase Porifera research exploration especially on Sponges biodiversity in the country. For instances, The Sponge Barcoding Project (www.spongebarcoding.org) provides DNA-based identification tools for poriferan species and this can be an excellent initial research direction where Malaysian researchers can steer toward.
Furthermore, it is crucial to keep up with global coral reef threats research, such as climate change and coral bleaching. This is because such research was not prioritized in Malaysian coral reefs research prior to the 2000s (Reaser et al., 2000; Donner et al., 2005). However, with recently increased threats to coral reefs, there has been a sharp increase in research interest/urgency to date from 2000–2021 (Fig. 2b). Likewise, the study on reef-associated bacteria can be increased in line with climate-related coral reef research as it is emergently studied globally in regard to coral disease and more recently coral bleaching (e.g., Aronson & Precht 2001; Rosenberg et al., 2007; Berumen et al., 2013; Boilard et al., 2020). Thus, principal coral reef research such as bleaching, and reef-associated bacteria should be addressed in Malaysia to provide a comprehensive understanding on the correlation of multiple ecological factors that is threatening marine ecosystem.
This study hopes to provide direction and focus on coral reefs studies within Malaysia in the future. One such example is the coral reef connectivity topic, which is crucial for informing both conservation and management decisions pertaining to coral reef resilience, persistence, and recovery (e.g., Sale et al., 2005; Almany et al., 2009; McCook et al., 2009; Berumen et al., 2013). In this study, the RES (n = 947) recorded slightly more papers published on this topic as compared to the GBR (n = 934). This was not observed in Berumen et al. (2013), as connectivity papers in RES were minimal prior to 2013 showing that the country has made a clear research focus to keep up with world coral reef research trends. Thus, from the compiled principal research topics in coral reefs, Malaysia should focus on studies of connectivity, and coral bleaching alongside nascent topics (Reef-associated bacteria) that will inform understanding on worsening coral degradation in terms of coral health and coral disease to support coral resilience. Additionally, coral reef research in Malaysia could benefit from a global recognized ocean observing system (GOOS) emerged from OceanObs’09 conference which was proposed to support the establishment of an integrated and sustained observing system including the concept of essential ocean variables (Miloslavich et al., 2018). One such example is the continuous effort of reef survey within the country conducted by Reef Check Malaysia (Chelliah et al., 2012; Hyde et al., 2013) which help to inform management strategies based on reef condition. Therefore, the concept of essential ocean variables not limited to biological, should be adopted by future Malaysian coral reef trajectory such as the physical and biogeochemical observations.
Research theme and Marine Ecoregions within Malaysia
From the reviewed WoS search categorizing each paper into Areas within Malaysia (WCPM; ECPM; Sabah; Sarawak) and research categories (nine biological, three non-biological), majority studies (63.29%) were conducted within ECPM and Sabah (Fig. 3, Table S2, S3). This is probably due to the effort from the local authorities, considering the high economic value of coral reefs resources, to conserve the coral reefs within these two regions as ECPM (South China Sea) and Sabah (Sulu-Sulawesi) are both well-known for their coral reef richness and diversity (Asian Development Bank, 2014; Arai, 2015). In relation to this, active marine research were done by universities with facilities within the areas, namely Universiti Malaysia Terengganu, UMT (Institute Oceanography and Environment, INOS), Universiti Malaysia Sabah, UMS (Borneo Marine Research Institute, BMRI), Universiti Malaya, UM (Institute of Ocean and Earth Sciences, IOES), Universiti Kebangsaan Malaysia, UKM (Marine Ecosystem Research Centre, EKOMAR). In fact, on average across all the papers that were published recently (2017–2021, 5 papers from each year of publication), the WoS search found that 20 out of 25 papers from ECPM are with researchers affiliated with UMT and a similar trend from papers done in Sabah with 21 out of 25 papers are with researchers affiliated to UMS. Besides, there are 35 out of 42 MPAs within ECPM with coverage of ~ 93%, 1745.28/1859.48 km2 total MPA area out of Peninsular Malaysia. Meanwhile, Sabah and Sarawak have large MPAs areas such as Tun Mustapha Park (8987.63 km2) and Luconia Shoal National Park (10117.72km2) respectively (see Table S3) (Sabah Parks, n.d.; Sarawak Forestry Corporation, 2020). Thus, coral reef research in Malaysia at both ECPM and Sabah are well supported by available research institutes and the coverage of coral reefs at the areas.
On the other hand, WCPM (n = 176) has slightly more papers published than Sarawak (n = 110). With more studies leaning on Environment, MISC covers the aspects of sedimentation, coastal management, and mangroves-coral reef fisheries (e.g., Nickerson-Tietze, 2000; Abdullah et al., 2011; Zu et al., 2020). The WCPM lies along the narrow Straits of Malacca is one of the heavily exploited regions with industrial development and busy maritime industry causing alarming sedimentation (Yap et al., 2002; Mohamed et al., 2021). Therefore, coral reefs do not thrive here as the anthropogenic turbidity environment limits their growth (Safuan et al., 2018; Zweifler et al., 2021). Nevertheless, location-based bias was observed in the research trend, as the majority of Cnidaria publications from the WoS search were concentrated at Pulau Langkawi and Port Dickson, where coral reefs are more documented (Toda et al., 2007; Safuan et al., 2016).
Turbid coral reefs are a staple feature in WCPM; however, turbid coral reefs remain heavily unexplored as identifying and assessment of coral reefs are relatively difficult compared to clear water environments largely because of bad visibility (Zweifler et al., 2021). This is crucial as turbid reefs house one of the most resilient organisms, which may survive in marginal environments in climate change (Anthony & Larcombe, 2000; Goodkin et al., 2011; Browne et al., 2019). There are at least four Malaysian mainstream public research universities that had interest in turbid water coral reefs of WCPM: Universiti Kebangsaan Malaysia, Universiti Malaya, Universiti Sains Malaysia, and Universiti Teknologi MARA, Perlis Study (e.g., Lee & Mohamed, 2011 recorded and compared the sedimentation rate between different coastline within the country, Safuan et al. 2018 found that coral communities in WCPM are mostly formed by species with high tolerance to turbidity and sedimentation). The constant anthropogenic pressures present along the WCPM coastline may provide an open-tank studies between the WCPM (considerable pollution and high stress simulating climate induced impacts) and ECPM (less polluted, subject to further climate induced stressors) of distinct marine ecoregions that are parallelly separated by the Peninsular mainland. Future research should utilize this opportunity to steer towards investigating the effect of anthropogenic-accelerated climate impacts to coral reef ecosystem and the research output from WCPM may serve as an indicator for future reefs pattern. Therefore, continuous research efforts should be done based on preliminary studies within the country as turbid coral reefs may be more resilient to climate change impacts (Morgan et al., 2017; Zweifler et al., 2021) which the findings can feed into global marine research.
Overall, Sarawak is considerably the most understudied region because of its least publications on all topics. Research interests in this region mainly focused on geological and environmental aspects of the rich carbonate deposition that is widespread around offshore Sarawak (Zampetti et al., 2004; Janjuhah & Alansari 2020). On the other hand, coral reef studies are limited within the region with little to no comprehensive coral cover studies in structural maps out of coral communities. It’s no surprise as coral reefs are considered a rare feature in Sarawak according to Sarawak Forestry Corporation (n.d.) due to the marine geographical location of Sarawak coastline with lack of rocky bottom. Besides, there are numerous river flow from the mainland contributing to sedimentation causing the formation of clay bottom seabed which is not desirable for reef building corals (Pilcher & Cabanban 2000). Nevertheless, historical records (Leem et al., 2022) of coral reefs at the turbid areas present great research opportunities in the aspect that comparison of coral reefs biodiversity, structural components between disparate marine ecoregions within the country will provide better information and understanding for conserving the coral reef ecosystem.
The coral reefs’ richness has certainly sparked high research interests in both ECPM and Sabah, especially from the biological taxa of Cnidaria, as the group is the keystone animal in building coral reefs (Praveena et al., 2012). This is followed by Pisces for the high demand for fishery products in Malaysia at which the fisheries sector produced approximately 1,654,217.98 tonnes of food fish with a value of RM6,467.40 million in the year of 2007 (Nurnadia et al., 2011). Statistics in the year 2000 showed that per capita fishery products consumption was 58kg per person in Malaysia (Nurnadia et al., 2011; Anual et al., 2018), two-fold that in Australia which was 25kg per person (Birch, Lawley & Hamblin, 2012). Hence, Pisces studies are economically important in the nation. Marine fishes population depends on a healthy ecosystem to thrive, the structural complexity in coral reef ecosystems has long been recognized for the assemblage and abundance of reef fishes (Roberts & Ormond, 1987; Brandle et al., 2016; Darling et al., 2017). Although the Pisces, Cnidaria, and relevant ‘Coral Reef’ studies are considerably prevalent compared to other topics, more studies are needed to address the gap in knowledge in pacing up with global marine research in the effort.
Aside from diversity checklist studies, Malaysian coral reefs research also involved in ecosystem conservation and recovery mitigation. To improve the coral reef coverage and resilience, some studies suggested using artificial reefs as a supplementary effort (Puspasari et al., 2020). However, studies on artificial reefs in Malaysia are at a nascent stage. Instead, many studies focused on resource enhancement especially fish aggregation (Bohnsack & Sutherland, 1985; Reimer et al., 2022). Although there were several publications on artificial reefs of Malaysia in WoS (4 papers published consecutively in the year of 2018 alone; Jani et al., 2018; Zakariya & Sakai, 2018; Salleh et al., 2018; Fam et al., 2018), the main focus of such studies was to improve fish stocks rather than rehabilitating the coral reef ecosystem (Reimer et al., 2022). Through this observation, it is suggested that Malaysia may adopt the concept of restoration ecology as an active management instrument highlighted by Hobbs & Harris (2001). A long-term innovative monitoring in the aspect of Artificial Reef's sustainability must be established rather than focusing on fish aggregation only.
Overall, ECPM and Sabah have more established coral reefs research efforts as compared to WCPM and Sarawak. While it is apparent that the understudied regions need improvement on coral reef research, a comprehensive coral mapping could provide a baseline information for coral reefs research in the country. The application of satellite-based remote sensing in coral reef mapping has been widely used over the decades (Green et al., 1996, da Silveira et al., 2021) largely due to its capability to map coral reef structural complexity and regime surrogates over large areas (Hedley et al., 2016). With the recent advancement and application of remote sensing technologies such as the Light Detection and Ranging (LiDAR) technology, the mapping quality and quantification of coral reef complex ecological systems can be performed at a finer scale (Green et al., 1996; Hedley et al., 2016; da Silveira et al., 2021) at which the coral reef’s geomorphology can be showcased in a three-dimensional perspective. However, despite the increase of LiDAR applications, it has not been used to date for this purpose at Malaysia’s local and regional levels. Therefore, researcher could utilize this technology to screen both identified and potentially unidentified coral reefs area in the country to provide a groundwork to coral reefs studies.
Research Limitation
Presently, the screening protocols of all the papers from this WoS search, the inaccurate and random inclusion of non-related studies are at high frequency with almost half of the studies being ruled out from the initial search. Upon closer examination, we found that there are several reasons for the misnomer of the WoS search. For instance, one-third of the papers we ruled out was conducted outside of the country but are written by researchers who have affiliation with research institutions in the country (e.g., Eriksson et al., 2015 where the author is from WorldFish, a marine research institute based in Malaysia). Meanwhile, there are also random inclusions of papers non-related to coral reef studies possibly due to the use of inconsistent wording in the studies. For example, chemistry and engineering-related studies use the word “coral-like porosity” to describe the structure of a research object (e.g., Pudukudy & Yaakob, 2014; McNeill et al., 2013 included in this WoS search). Therefore, the high misnomer of the WoS search indicated a rather inconsistent journal depository style related to coral reef research and screening protocols are necessary to eliminate random inclusions.
Besides, the findings showed that coral reef research in Malaysia is relatively lacking as compared to other regions of the world, and the low number of coral reef publications is more apparent after a screening protocol for each WoS search which has been mentioned above. However, results pointed only limited to the indexed journals that were archived in the Web of Science (WoS). Manual search from several databases such as google scholar, local university journals, and government databases contain research papers and reports on coral reefs research that were not indexed in WoS. These types of papers are categorized as grey literatures (Reimer et al., 2019). There are two main reasons behind the existence of grey literature in Malaysian research: (1) the usage of the national language in some Malaysia research literature, and (2) proceedings and articles which are not recognized by WoS (e.g., SCOPUS, MyCite.).
Non-English language native countries have long been using their native languages in scientific writings (Reimer et al., 2019). This includes Malaysia, which actively promotes the use of the Malay language (Bahasa Melayu (BM)) as the main communication medium, including the scientific language (Musa et al., 2014). With WoS not recognizing scientific reports in BM (e.g., Sains Malaysiana, Pertanika), plenty of coral reef related knowledge in Malaysia may be side-lined. This is especially prevalent in government related documents (in BM), which might change the perspective of the coral reef research in the country. Hence, we suggest a translating initiative of non-English literature in the country to enable more access from the international science community in steering future research. In the future, we suggest the idea of including grey literatures to gain a complete picture of marine sciences research in Malaysia.
Apart from the WoS, there are a number of alternatives established bibliometric methods, such as the SCOPUS and some locally recognized database (e.g., MyCite) in Malaysia. While SCOPUS is a viable alternative, the WoS database has better matrices over SCOPUS when it comes to STEM subjects (Mongeon & Paul-Hus, 2016; Zhu & Liu, 2020). Moreover, research institutes in the country recognize WoS as the primary reference. Hence, this study mainly used WoS as the literature compilation to best present the natural science literature of coral reef research. Nevertheless, the results of bibliometric analyses may vary depend on the database used. Therefore, the selection of database for comparative research such as meta-analysis required a certain extent of evaluation on several factors such as languages, institutions or countries. Thus, this paper encourages the idea of grey literature review, which offer another perspective of coral reef research in Malaysia. A comparison between database specific results can be made to justify an inclusive literature review.