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Abstract This study was conducted to investigate the energy mobilisation preference and ionoregulation pattern of female tilapia, Oreochromis sp. living in different environments. Three different treatments of tilapia as physiology compromising model were compared; tilapia cultured in recirculating aquaculture system (RAS as Treatment I—RAS), tilapia cultured in open water cage (Treatment II—Cage) and tilapia transferred from cage and cultured in RAS (Treatment III—Compensation). Results revealed that tilapia from Treatment I and III mobilised lipid to support gonadogenesis, whilst Treatment II tilapia mobilised glycogen as primary energy for daily exercise activity and reserved protein for growth. The gills and kidney Na+/K+ ATPase (NKA) activities remained relatively stable to maintain homeostasis with a stable Na+ and K+ levels. As a remark, this study revealed that tilapia strategized their energy mobilisation preference in accessing glycogen as an easy energy to support exercise metabolism and protein somatogenesis in cage culture condition, while tilapia cultured in RAS mobilised lipid for gonadagenesis purposes.

The ongoing climate change is resulting in elevating temperatures and reduced pH levels in the marine environment. This work reports on the interactive effects of these two factors on growth and physiological responses of Pacific whiteleg shrimps (Litopenaeus vannamei), with a very important commercial shrimp specie. The study examines the interactive effects of temperature (28 versus34°C) and pH (6 versus 8) were examined at four combinations: (28°C and pH 8 (N28); 34°C and pH 8 (N34); 28°C and pH 6 (A28); and 34°C and pH 6 (A34), over a 30 days period. A combination of a high temperature and low pH (i.e., A34) was found to impose a high metabolic burden on the shrimp, resulting in an increased food intake and elevated osmorespiration responses relative to control, but no improvement in growth. The A34 stress combination increased ammonia excretion 2-fold relative to control, and increased a 40 % rise in metabolic oxygen uptake. Under A34 stress, glycogen and lipid reserves in both muscle and hepatopancreas were mobilized to support basal metabolic needs, resulting in growth suppression. The combined thermal-pH stress A34 did not affect the calcium and magnesium content of muscle and shell, which are essential minerals for exoskeleton and structural development. Although the shrimp can survive under high temperature-low pH stress conditions, their growth rate was compromised.

Current water warming and freshwater acidification undoubtedly affect the life of aquatic animals especially ammonotelic teleost by altering their physiological responses. The effect of temperature (28 °C vs 32 °C) and pH (7 vs. 5) on the metabolic compromising strategies of Hoven's carp (Leptobarbus hoevenii) was investigated in this study. Fishes were conditioned to (i) 28 °C + pH 7 (N28°C); (ii) 32 °C + pH 7 (N32°C); (iii) 28 °C + pH 5 (L28°C) and (iv) 32 °C + pH 5 (L32°C) for 20 days followed by osmorespiration assay. Results showed that feeding performance of Hoven's carp was significantly depressed when exposed to low pH conditions (L28°C and L32°C). However, by exposed Hoven's carp to L32°C induced high metabolic oxygen intake and ammonia excretion to about 2x-folds higher compared to the control group. As for energy mobilization, Hoven's carp mobilized liver and muscle protein under L28°C condition. Whereas under high temperature in both pH, Hoven's carp had the tendency to reserve energy in both of liver and muscle. The findings of this study revealed that Hoven's carp is sensitive to lower water pH and high temperature, thereby they remodeled their physiological needs to cope with the environmental changes condition.

Abstract Background The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has estimated that invasive alien species (IAS) might cause billions of dollars of losses every year across the world. One example is South-East Asia, where IAS have caused an estimated loss of 33.5 billion USD, affecting the environment, human health, and agricultural production. Factors associated with climate change, such as increased carbon dioxide (CO2), heavy precipitation, and elevated temperatures is expected to facilitate biological invasion, leading only to further financial and public health loss. Thus, further study is needed to identify, collate and categorise what evidence exists on the impacts of climate change on fish and shellfish species that contribute to the list of “One Hundred of the World’s Worst Invasive Alien Species” as identified by the International Union for Conservation of Nature’s (IUCN). Such mapping will identify regions more at risk of biological invasion as climate change progresses. Methods We outline a systematic mapping review protocol that follows the Guideline and Standards for Evidence Synthesis in Environmental Management and RepOrting standards for Systematic Evidence Syntheses (ROSES). We describe how peer-reviewed articles will be collected from Web of Science and Scopus, and then analyzed to create knowledge maps on the impact climate change has on invasive species. Finally, we speculate on how our results will aid future management of invasive species in the light of climate change.

Abstract Background Climate is one of the most important driving factors of future changes in terrestrial, coastal, and marine ecosystems. Any changes in these environments can significantly influence physiological and behavioural responses in aquatic animals, such as crustacea. Crustacea play an integral role as subsistence predators, prey, or debris feeders in complex food chains, and are often referred to as good indicators of polluted or stressed conditions. They also frequently have high production, consumption, and commercial significance. However, crustacean’s responses to climate change are likely to vary by species, life-history stage, reproduction status and geographical distribution. This map is undertaken as part of the Long-Term Research Grant project which aims to identify any interactive effect on physiological compensation and behavioural strategy of how marine organisms, especially crustaceans, deal with stress from environmental change. Our proposed map will aim to outline the evidence currently existing for the impacts of climate change on the physiology and behaviour of important aquaculture crustacean species within Asia. Methods We will document peer-reviewed articles in English using published journal articles and grey literature. Two bibliographic databases (Scopus and Web of Science) and multiple organizational websites with Google scholars will be searched. The systematic map protocol will follow in accordance with the Collaboration for Environmental Evidence Guidelines and Standards. Literature will be screened at the title, abstract, and full-text level using pre-defined inclusion criteria. The map will highlight marine crustacea physiological compensation and behavioural strategies to cope with climate change. It will also improve our knowledge of the available evidence and current gaps for future research recommendations.

Climate change research on major aquatic species assists various stakeholders (e.g. policymakers, farmers, funders) in better managing its aquaculture activities and productivity for future food sustainability. However, there has been little research on the impact of climate change on aquatic production, particularly in terms of scientometric analyses. Thus, using the bibliometric and scientometric analysis methods, this study was carried out to determine what research exists on the impact of climate change on aquatic production groups. We focused on finfish, crustaceans, and molluscs. Data retrieved from Web of Science was mapped with CiteSpace and used to assess the trends and current status of research topics on climate change associated with worldwide aquatic production. We identified ocean acidification as an important research topic for managing the future production of aquatic species. We also provided a comprehensive perspective and delineated the need for: i) more international collaboration for research activity focusing on climate change and aquatic production in order to achieve the United Nations Sustainable Development Goal by 2030; ii) the incorporation of work from molecular biology, economics, and sustainability.

Length-weight relationship (LWR), condition factors, and trophic level of Zenarchopterus buffonis from the coastal waters of Malaysia were evaluated between November 2013 and March 2014. Three hundred individuals of Z. buffonis ranging between 8.7−16.0 cm total length and 3.67−22.19 g body weight were investigated in this study. The length-weight relationship demonstrated that the parameter b values at Sungai Likas, Tanjung Belungkor, Langkawi, Klang, and Matang were 3.3114, 3.0534, 2.5442, 2.2018, and 2.8998, respectively, which suggested positive and negative allometric growth patterns for this species. Specimens from Matang recorded the lowest mean condition factor, K (0.2292±0.0578) whereas Tanjung Belungkor displayed the highest value of 0.6556±0.0526. Matang was discovered to display the lowest relative condition factor (Kn) of 0.0330±0.2336, whereas Klang had the highest Kn value of 3.5097±0.4232. The trophic level for Z. buffonis was analyzed based on 84 specimens. Gut content analysis revealed that Z. buffonis consume primarily insects (57%), followed by plant materials (33%), and crustaceans (10%). The calculated TROPH values (1−3.2) signified that Z. buffonis has an omnivorous feeding habit. This study provides the pioneer description of LWR parameters, condition factors, and diet preferences for Z. buffonis, which would be beneficial for the sustainable fishery management in the coastal waters of Malaysia and neighboring provinces.

A specimen (125.5 mm in standard length) of bridled jawfish, Opistognathus nigromarginatus Rüppell, 1830 was collected from the Pulau Bidong, Terengganu, Malaysia using research trawler. Opistognathus nigromarginatus previously has been recorded from Southern Africa to the Persian Gulf, India, Thailand, and Vietnam. We document the first record of this species in Malaysia and the southernmost occurrence in the South China Sea and Western Pacific Ocean. Detailed morphometric and meristic data are presented along with brief diagnostic characters.

The growth pattern, diet and reproductive biology of the clownfish Amphiprion ocellaris collected from waters of Pulau Tioman were investigated. The length-weight relationship showed an isometric growth pattern (b = 3) in A. ocellaris. The stomach contents mainly consisted of zooplankton and algae, which showed that the fish is omnivorous and was confirmed by trophic level analysis (2.98 ± 0.29). Fecundity of A. ocellaris ranged from 23-1518 with mean egg count of 582 ± 478, and has positive relationships with body length, body weight, eviscerated weight and ovary weight. The gonads were also described and examined histologically. The ovaries showed 4 stages of maturity, displaying different colours for each stage. The different developments of oocytes were also found in each stage of maturity. The males and non-breeders comprised of both testicular and ovarian tissues. In the males, the testicular tissues were more prominent in the ovotestes, whereas in non-breeders the primary oocytes were more prominent. Absence of testicular tissue in ovaries of females showed that the fish is a protandrous hermaphrodite and sex change may not be reversible. Similar observations have been reported in A. ocellaris of other countries and other Amphiprion species indicating that Amphiprion species show consistency in their reproduction strategy throughout their range. Keywords: Reproductive biology, Growth pattern, Stomach content, Amphiprion ocellaris, Protandrous hermaphrodite

An integrated experiment was performed on juvenile Malabar blood snapper (Lutjanus malabaricus) to investigate the effect of temperature and diet in their pepsin activities in relation with digestive somatic index (IDS) and relative gut length (RGL). One hundred twenty L. malabaricus juvenile (13–15 cm) were equally distributed among four exposed temperature treatments (22, 26, 30 and 34 °C) representing their seasonal range and to account for end of century predicted temperatures, and two diets as commercial pellet and natural shrimp. After 7 days of acclimation period fish were reared for 30 days in twenty four 400 l glass aquaria at a stocking density of 5 fish tank−1. All treatments were three replications. The result showed that, IDS and RGL gradually decreased with increasing temperature up to 30 °C and again increase at 34 °C. And the values were also higher in pellet feeding fish than shrimp feeding fish at all the temperatures. Alternatively, in pepsin activity, an increased activity was seen between 26 °C to 30 °C and this activity was significantly higher than the 22 °C and 34 °C (P

The influences of live and formulated feeds on growth performances, muscle fibers morphometry and muscle growth-related gene expression of Malaysian mahseer, Tor tambroides larvae were evaluated in indoor nursery rearing system. Quadruplicate groups of T. tambroides larvae (0.07 ± 0.01 g, mean ± SE) were stocked in sixteen aquaria (60 × 30 × 30 cm), randomly arranged in four dietary treatments viz. larvae fed artemia (LA), moina (LM), daphnia (LD) and formulated feed (FF) with stocking density of 34 larvae per aquarium. The larvae were fed to visually near satiation in two equal feedings per day, seven days per week for 75 days. The growth-related parameters (mean weight gain and specific growth rate) were significantly highest in treatment FF, followed by treatment LA and the lowest in treatment LD or LM. Histological observation and muscle morphometric analysis revealed that mosaic hyperplasia was observed after 50 days of the feeding trial. Hypertrophic (diameter class 50 = 40 > d ≤ 50 μm and class 60 = d > 50 μm), but not hyperplastic (diameter class ≤10 μm), muscle fibers frequencies were significantly highest in larvae fed FF compared to those fed live feeds. The entire open reading frame cDNA sequences of two important growth-related genes, myogenin and MyoD, were successfully amplified and cloned from T. tambroides larvae. The nucleotide sequences alignment using CLUSTAL W in BioEdit program of both MyoD and myogenin genes showed the sign of existence of isoforms and highly conserved with other cyprinid fishes. Real-time PCR data demonstrated that myogenin and MyoD gene expressions were significantly upregulated in larvae fed FF. The results of the present experiment concluded that the nursery rearing of T. tambroides larvae with formulated feed showed augmented muscle growth and upregulated growth-related gene expression than feeding live feeds.

In tropical regions, different species of fiddler crabs coexist on the mangrove floor, which sometimes makes it difficult to define species-specific habitat by visual inspection. The aim of this study is to find key environmental parameters which affect the distribution of fiddler crabs and to determine the habitats in which each species was most abundant. Crabs were collected from 19 sites within the mudflats of Sepang-Lukut mangrove forest. Temperature, porewater salinity, organic matter, water content, carbon and nitrogen content, porosity, chlorophyll content, pH, redox potential, sediment texture and heavy metals were determined in each 1 m2 quadrate. Pearson correlation indicated that all sediment properties except pH and redox potential were correlated with sediment grain size. Canonical correspondence analysis (CCA) indicated that Uca paradussumieri was negatively correlated with salinity and redox potential. Sand dwelling species, Uca perplexa and Uca annulipes, were highly dependent on the abundance of 250 μm and 150 μm grain size particles in the sediment. Canonical Discriminative Analysis (CDA) indicated that variation in sediment grain size best explained where each crab species was most abundant. Moreover, U. paradussumieri commonly occupies muddy substrates of low shore, while U. forcipata lives under the shade of mangrove trees. U. annulipes and U. perplexa with the high number of spoon tipped setae on their second maxiliped are specialized to feed on the sandy sediments. U. rosea and U. triangularis are more common on muddy sediment with high sediment density. In conclusion, sediment grain size that influences most sediment properties acts as a main factor responsible for sediment heterogeneity. In this paper, the correlation between fiddler crab species and environmental parameters, as well as the interaction between sediment characteristics, was explained in order to define the important environmental factors in fiddler crab distributions.

In mangrove ecosystems, litter fall accumulates as refractory organic carbon on the sediment surface and creates anoxic sediment layers. Fiddler crabs, through their burrowing activity, translocate oxygen into the anoxic layers and promote aerobic respiration, iron reduction and nitrification. In this study, the effects of four species of fiddler crabs (Uca triangularis, Uca rosea, Uca forcipata and Uca paradussumieri) on organic content, water content, porosity, redox potential and solid phase iron pools of mangrove sediments were investigated. In each crab’s habitat, six cores down to 30 cm depth were taken from burrowed and non-burrowed sampling plots. Redox potential and oxidized iron pools were highest in surface sediment, while porosity, water and organic content were higher in deeper sediment. Reduced iron (Fe (II)) and redox potential were significantly different between burrowed and non-burrowed plots. Crab burrows extend the oxidized surface layer down to 4 cm depth and through the oxidation effect, reduce the organic content of sediments. The effects of burrows varied between the four species based on their shore location. The oxidation effect of burrows enhance the decomposition rate and stimulate iron reduction, which are processes that are expected to play an important role in biogeochemical properties of mangrove sediments.

A specimen (125.5 mm in standard length) of bridled jawfish, Opistognathus nigromarginatus Rüppell, 1830 was collected from the Pulau Bidong, Terengganu, Malaysia using research trawler. Opistognathus nigromarginatus previously has been recorded from Southern Africa to the Persian Gulf, India, Thailand, and Vietnam. We document the first record of this species in Malaysia and the southernmost occurrence in the South China Sea and Western Pacific Ocean. Detailed morphometric and meristic data are presented along with brief diagnostic characters. [ABSTRACT FROM AUTHOR]

Macrobrachium rosenbergii is one of the shellfish species with high aquaculture value due to its increasing market demand. However, the comparatively low production volume compared to demand coupled with the rapid decline of the natural environment, consequently, drives the potential depletion of the wild population. The decrease in water pH related to anthropogenic pollution is one of the most critical factors affecting the early life performances of M. rosenbergii. Therefore, this study was designed to examine the effect of low water pH on feeding, growth and development of M. rosenbergii early life stages. Experimental water pH was set as neutral (7.7 ± 0.4); mild-acidic (6.4 ± 0.5) and acidic (5.4 ± 0.2) with triplication at a stocking density of 2 larvae/L for 30 days. As expected, M. rosenbergii larvae were highly sensitive to acidic pH with no larvae survived beyond 48 h of exposure. Feeding, survival and growth of larvae were adversely affected by mild-acidic pH exposure as compared to neutral pH. Larvae exposed to mild-acidic water pH experienced a prolonged larval period and only metamorphosed to the post-larval stage at day-30. Whilst under neutral water pH, larval that metamorphosed to post-larval was first observed on day-23. The negative impact of decreased pH, even in mild-acidic pH exposure, on the feeding, survival, growth and development of M. rosenbergii larvae highlights the urgency of periodic pH monitoring during M. rosenbergii larviculture.

This study explores the gastrointestinal evacuation time (GET) and gastrointestinal evacuation rate (GER) of the popular Sabah grouper (Epinephelus fuscoguttatus × E. lanceolatus) adults using two established methods (X-radiography and serial slaughter) and square root modeling using different temperatures: 28 °C, 30 °C, 32 °C, and 34 °C and different diets: pellet (ash: 11.4 ± 0.08; moisture: 29.0 ± 0.01; protein 37.5 ± 0.80; lipid 15.0 ± 0.13) and trash fish: Sardinella sp. (ash: 2.3 ± 0.15; moisture: 78.5 ± 0.33; protein 55.4 ± 0.62; lipid 7.3 ± 0.25) and the impact on growth indices. The results indicate that the GET shortened as temperature increased from 28 °C to 30 °C; however, it was prolonged when it surged to 32 °C and 34 °C. The groupers fed with trash fish at a temperature of 30 °C had the shortest GER (0.41 ± 0.10 g hr−1) whereas groupers fed with pellet at 34 °C had the longest GER (0.95 ± 0.02 g hr−1). Likewise, the highest SGR (16.25 ± 2.11% day−1) was observed at 30 °C for groupers fed with a trash fish diet. The condition (K) value was lowest at 34 °C for groupers fed with a pellet diet (1.01 ± 0.04) and highest at 30 °C for groupers fed with trash fish (1.45 ± 0.04). Our results suggest that temperature and diet influence growth indices and GE of adult Sabah groupers. Incorporation of this information will allow better management of this commercially important grouper species when reared in a controlled aquaculture environment.

Elevated ocean water temperature influences the physiological properties of fishes. This study is expected to characterize the oxygen consumption rate (OCR) and gill morphology in different temperature in hybrid grouper, tiger grouper × giant grouper (TGGGH). TGGGH specimens were distributed into four temperature groups starting from 22, 26, 30 and 34 °C within a recirculatory system under controlled conditions for 30 days in triplicates. Intermittent flow respirometry was directed to distinguish the impact of temperature on the OCR, and scanning electron microscopy was conducted to observe the gill morphology. Results indicated that the OCR of TGGGH increased significantly from 22.98 ± 1.16 mg O2 h−1 to 37.08 ± 1.56 mg O2 h−1 when temperature increased from 22 to 34 °C. Values of respired energy (RE) increased from 456.35 ± 11.41 Jh−1 at 22 °C to 737.88 ± 3.79 Jh−1 at 34 °C. Meanwhile, values of temperature quotients (Q10) were maximum at 22 °C–26 °C and minimum at 26 °C–30 °C. The favored temperature assessed from Q10 was between 26 °C and 30 °C. Gill lesions were significantly observed at 22 °C and 34 °C. The outcomes proposed that this fish species may neglect to maintain sufficient O2 uptake in future atmospheric situations. Thus, optimum oxygen consumption is required for maintaining the TGGGH in aquaculture environment.

The population genetic diversity and demographic history of the longtail tuna Thunnus tonggol in Malaysian waters was investigated using mitochondrial DNA D-loop and NADH dehydrogenase subunit 5 (ND5). A total of 203 (D-loop) and 208 (ND5) individuals of T. tonggol were sampled from 11 localities around the Malaysian coastal waters. Low genetic differentiation between populations was found, possibly due to the past demographic history, dispersal potential during egg and larval stages, seasonal migration in adults, and lack of geographical barriers. The gene trees, constructed based on the maximum likelihood method, revealed a single panmictic population with unsupported internal clades, indicating an absence of structure among the populations studied. Analysis on population pairwise comparison ФST suggested the absence of limited gene flow among study sites. Taken all together, high haplotype diversity (D-loop = 0.989–1.000; ND5 = 0.848–0.965), coupled with a low level of nucleotide diversity (D-loop = 0.019–0.025; ND5 = 0.0017–0.003), “star-like” haplotype network, and unimodal mismatch distribution, suggests a recent population expansion for populations of T. tonggol in Malaysia. Furthermore, neutrality and goodness of fit tests supported the signature of a relatively recent population expansion during the Pleistocene epoch. To provide additional insight into the phylogeographic pattern of the species within the Indo-Pacific Ocean, we included haplotypes from GenBank and a few samples from Taiwan. Preliminary analyses suggest a more complex genetic demarcation of the species than an explicit Indian Ocean versus Pacific Ocean delineation.

The present study was carried out to analyse the effect of water temperature on two components: (1) growth performance, and (2) gastric emptying time (GET) of African catfish Clarias gariepinus fingerlings. After 70 days, it was observed that experimental temperatures had no significant effects on the growth performance parameters, except for food conversion ratio (FCR) and food conversion efficiency (FCE). GET observation through X-radiography denoted that the shortest GET (10 h) was observed in fish reared at 32 °C and the longest GET (16 h) was observed in fish reared at 26 °C. The rapid digestion rate coincides with the FCR and FCE obtained in this study. Considering the limited scope of our study, more extensive studies on the impact of water temperature on other fish physiological parameters should be pursued. A better understanding of this research topic would be beneficial for the growth of African catfish fingerling aquaculture.

Hybrid grouper (Epinephelus fuscoguttatus [TG] × E. lanceolatus [GG]) juveniles were evaluated in terms of their blood hematology and biochemical levels after 60 days of exposure to different temperatures (22 °C, 26 °C, 30 °C, and 34 °C) in triplicate (20 fish/tank; body weight 200 ± 15 g; length 22.5 ± 1 cm). The fish were fed daily with commercial pellets (42% protein, 9% ash, and 11% lipid) or shrimp (42% protein, 9% ash, and 11% lipid). Results showed that the blood hematologic parameters of the fish fed with shrimp at 26 °C were significantly better than those at other temperatures. The lowest stress level measured in terms of glucose (26 ± 10 mg dL−1) and cortisol concentrations (0.5 ± 0.1 ng mL−1) after 60 days of the experiment were observed in the fish fed with shrimp at 26 °C compared with those fed with other diets and at other temperatures. Overall, the TGGG hybrid showed the highest red blood cell and total protein counts in fish fed with a shrimp diet at 26 °C, which were healthful and less stressful conditions. Thus, the health of TGGG hybrid fed with shrimp was better than that of fish fed with other diets and at other temperatures. These findings would be useful for further studies on the management of the TGGG hybrid to increase production. Keywords: Aquaculture, Hematology, Cortisol, Grouper, Temperature

The effects of temperatures (22, 26, 30 and 34 °C) and diets (commercial pellet and shrimp) on the growth properties and gastric emptying time (GET) of the tiger grouper × giant grouper (TGGG) hybrid were analyzed over a 30 day experimental period under controlled laboratory conditions. Food consumption (FC), food conversion rate (FCR), specific growth rate (SGR) and GET were significantly influenced by temperature and diet type. The highest mean SGR (1.00% BM day−1, p 0.05) were observed between any of the groups at 22 and 34 °C fed on either the shrimp or the pellet diet. The lowest statistically significant (p