Eastern Indian Ocean Research Articles

Effects of Climate Variability on Two Commercial Tuna Species Abundance in the Indian Ocean

Oceanic temperature fluctuations are one of the leading factors affecting marine fish populations. Indian Ocean Dipole (IOD), characterized as the sea surface temperature (SST) anomaly change, is an ocean–atmosphere interactive process causing interannual climate variability in the Indian Ocean. Influences of the IOD on the tuna catch rates are supported by previous research. Yet, there remains limited information about the impacts on the abundance of tuna stocks. In this study, we used the standardized Catch Per Unit Effort (CPUE) index to present the stock abundance and compared the effects of the IOD on the bigeye tuna (Thunnus obesus) and yellowfin tuna (Thunnus albacares) among different management areas of the Indian Ocean Tuna Commission (IOTC). Results show significant correlations between IOD events on both species’ abundance in the tropical western Indian Ocean. However, in the tropical eastern Indian Ocean and the southern Indian Ocean, neither bigeye nor yellowfin tuna abundances were significantly correlated by the IOD. For the whole Indian Ocean, IOD was significantly correlated uniquely with the yellowfin tuna abundance. Our results emphasized the importance of evaluating the climate variability effects over fisheries abundance species by species and per fishing areas analyses.

Surface cross-equatorial pathways of seawater from the Bay of Bengal

Cross-equatorial pathways of heat and salt in the Eastern Indian Ocean are analyzed using Lagrangian trajectories based on the ECCO2 model simulation and drifter-derived currents combined with Argo data. The results show that most of the particles released in the Bay of Bengal move across the equator near the eastern boundary of the upper Indian Ocean (< 50m) during the southwest monsoon season and join the South Equatorial Current of the wind-driven circulation. Meridional salt and heat transports associated with the cross-equatorial currents feature significant seasonal variations, with stronger southward transports during the southwest monsoon than northward transports during the northeast monsoon, which are correlated significantly with the surface Ekman transports. The estimated annual mean salt and heat transports, based on the model (observational) data, are -0.06×109 (-0.11×109) kg·s-1 and -0.20 (-0.38) PW (1PW = 1015 W), respectively, southward across the equator.

Variations in dissolved organic matter chemistry on a vertical scale in the eastern Indian Ocean

Oceans cover approximately 71% of the Earth's surface area, which is why some people refer to the Earth as a large water sphere. Marine dissolved organic matter (DOM) constitutes the main carbon pool for biogeochemical cycles and plays an important role in global carbon dynamics. Here, the molecular composition and component characteristics of surface (5 m), deep chlorophyll maximum (DCM), and deep (2000 m) layer DOM in the eastern Indian Ocean (EIO) were investigated using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and three-dimensional fluorescence spectroscopy. Thousands of individual DOM formulas (approximately 3716–6986 formulas) were detected at 100–700 Da, showing a Gaussian distribution. The elements carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and sulfur (S) were detected and constituted four formula classes in solid-phase extracted marine DOM samples. Furthermore, the order of the percent intensity of the formulas was CHO > CHNO > CHOS > CHNOS. Carboxylic-rich alicyclic molecule (CRAM) compounds, as part of recalcitrant DOM (RDOM), were detected at 61.32%-78.77% (by intensity). In addition, the concept of islands of stability (IOS, approximately 3.99%-11.22%) has been proposed in this study, representing the most stable components in the marine environment. Such molecular formulas as described above probably contribute to increased RDOM content in the EIO and potentially reflect enhanced accumulation or sequestration of RDOM in the deep layer. The variation in the spectroscopic indices (FI, β/α, BIX, and HIX) and fluorescent components (C1 to C4) with depth indicates a shift from protein-like to humic-like components, leading to gradual aging of the water column. In brief, this study relies on data from marine DOM in the EIO to provide a molecular and chemical background for global models of marine DOM production, transformation and sequestration.

Spatial‐Temporal Variability and Sources of Lead (Pb) in the Indian Ocean and Asian Marginal Seas

AbstractSince North America and European countries phased out leaded gasoline, Asia has become the major contemporary lead (Pb) source to the marine environment, at first from leaded gasoline, but more recently from coal burning and other high‐temperature industrial activities (Flegal et al., 2013, https://doi.org/10.1080/10643389.2012.671738; Lee et al., 2014, https://doi.org/10.1016/j.epsl.2014.04.030). Pb in the Indian Ocean remains relatively under‐evaluated after ∼2000 and is further complicated by various oceanic processes (e.g., monsoons, boundary exchange with particulates). Here, we present three annually resolved coral skeletal Pb isotope and concentration records from the central and eastern Indian Ocean (Salomon Atoll, 1989–2009; Diego Garcia Atoll, 1999–2009; and Phuket Island, 1945–2010), and synthesize published coral/sedimentary records to reconstruct the spatial‐temporal variability of anthropogenic Pb around the region. Pb isotopes in all corals coherently fall along the mixing line between Asian aerosols and the natural crust. However, higher contributions of natural Pb are found in corals located in the coastal region than those in the open ocean, despite the greater contributions of anthropogenic Pb expected in coastal water near human emission sources. This geographical difference suggests that exchanges between dissolved Pb and natural particles at ocean boundaries significantly contribute to the Pb isotope compositions in regional seawater and are subsequently recorded in corals. The temporal variability of Pb concentrations in corals and sedimentary records signifies decreasing trends in Southeast Asia but increasing trends in South Asia. This study contributes new and timely Pb and Pb isotope data for the Indian Ocean and illustrates the importance of boundary exchange in marine Pb cycling.

Hydroclimate Variability in the Equatorial Western Indian Ocean for the Last 250,000 Years

AbstractIndian Ocean sea surface temperatures impact precipitation across the basin through coupled ocean‐atmosphere responses to changes in climate. To understand the hydroclimate response over the western Indian Ocean and equatorial east Africa to different forcing mechanisms, we present four new proxy reconstructions from core VM19‐193 (2.98°N, 51.47°E) that span the last 250 ky. Sub‐surface water temperatures (Sub‐T; TEX86) show strong precessional (23 ky) variability that is primarily influenced by maximum incoming solar radiation (insolation) during the Northern Hemisphere spring season, likely indicating that local insolation dominates the upper water column at this tropical location over time. Leaf waxes, on the other hand, reflect two different precipitation signals: δ13Cwax (in phase with boreal fall insolation) is likely reflecting vegetation changes in response to local rainfall over east Africa, whereas δDprecip (primarily driven by boreal summer insolation) represents changes in regional circulation associated with the summer monsoon. Glacial‐interglacial changes in ocean temperatures support glacial shelf exposure over the Maritime Continent in the eastern Indian Ocean and the subsequent weakening of the Indian Walker Circulation as a mechanism driving 100 ky climate variability across the tropical Indo‐Pacific. Additionally, the 100 ky spectral power in δDprecip supports a basin‐wide weakening of summer monsoon circulation in response to glacial climates. Overall, the proxy records from VM19‐193 indicate that both precession and glacial‐interglacial cycles exert control over hydroclimate at this tropical location.

Zonal current structure of the Indian Ocean in CMIP6 models

The Indian Ocean circulation system significantly affects local and global climate, with zonal currents as one of the most critical components. Zonal currents bridge the water mass and energy pathways between the eastern and western Indian Oceans. Nevertheless, their representation in the latest generation of coupled climate models has not been thoroughly evaluated. In this study, we examined the representation of the mean structure of the Indian Ocean zonal currents in 29 models from the Coupled Model Intercomparison Project Phase 6 (CMIP6). We confirmed that the CMIP6 ensemble represents the Indian Ocean zonal current structure but with a shallower Equatorial Undercurrent (EUC) core and an overestimated South Equatorial Current (SEC). Further, we investigated the physical properties in the Indian Ocean to understand simulated biases and inter-model spread in CMIP6 models, and found that the simulated biases of zonal currents are accompanied by hydrography and wind forcing simulation biases. This study compares the performance of CMIP6 models for simulating the Indian Ocean zonal currents and provides a reference for further studies on the Indian Ocean circulation system using coupled climate models.

North Atlantic cooling triggered a zonal mode over the Indian Ocean during Heinrich Stadial 1.

Abrupt changes in the Atlantic meridional overturning circulation (AMOC) are thought to affect tropical hydroclimate through adjustment of the latitudinal position of the intertropical convergence zone (ITCZ). Heinrich Stadial 1 (HS1) involves the largest AMOC reduction in recent geological time; however, over the tropical Indian Ocean (IO), proxy records suggest zonal anomalies featuring intense, widespread drought in tropical East Africa versus generally wet but heterogeneous conditions in the Maritime Continent. Here, we synthesize proxy data and an isotope-enabled transient deglacial simulation and show that the southward ITCZ shift over the eastern IO during HS1 strengthens IO Walker circulation, triggering an east-west precipitation dipole across the basin. This dipole reverses the zonal precipitation anomalies caused by the exposed Sunda and Sahul shelves due to glacial lower sea level. Our study illustrates how zonal modes of atmosphere-ocean circulation can amplify or reverse global climate anomalies, highlighting their importance for future climate change.

Dissolved trace metals (Fe, Mn, Pb, Cd, Cu, and Zn) in the eastern Indian Ocean

The distribution of trace metal micronutrients, which are crucial in many biotic enzymatic reactions, in the eastern Indian Ocean is not well understood. Here, we measured the concentrations of dissolved iron (dFe), manganese (dMn), lead (dPb), cadmium (dCd), copper (dCu), and zinc (dZn) at full depth in the water column of the eastern Indian Ocean (from the Bay of Bengal to the south of the equator). Throughout, dFe was replete in the surface mixed layer (SML). Moreover, the supply of dFe from below the SML and atmospheric deposition met the phytoplankton demand. In the thermocline, the subsurface maxima of dFe coincided with the dissolved oxygen (DO) minima. In addition, the distribution of Fe* in the Bay of Bengal indicated an additional input of dFe into the water column, apart from the biogenic organic particle regeneration. Unlike dFe, other trace metals were not enriched in the oxygen minimum zone, indicating that high Fe* value was caused by the release of dFe from the estuary or continental shelf under oxic conditions. In deep water, dFe, dMn, and dPb levels were low, whereas dCd, dCu, and dZn concentrations increased with depth. However, dFe and dMn levels were elevated in coastal bottom waters, where Fe* values were also high, indicating the supply of these metals from external sources. Exploring the relationship between trace metals and phosphate at the thermocline illustrated how oxygen-deficient conditions in the Bay of Bengal affect trace metal (dCd in particular) and phosphate ratios, compared with the global trend.

Two Types of Wintertime Teleconnection Patterns over the Western North Pacific Associated with Regionally Different Heating Anomalies

The turnabout of air temperature anomalies over East Asia between the first and second halves of winter 2020/21 was examined from a teleconnection perspective with regionally different convective heating anomalies over the Indo-western Pacific sector. In the first half of winter 2020/21, the air temperature over East Asia was lower than normal, accompanied by a pair of anticyclonic and cyclonic anomalies in the upper troposphere southeast of the Tibetan Plateau and north of Japan, respectively. This dipole pattern is newly referred to as the Southeast Asia–Japan (SAJ) pattern in this study, indicating the propagation of Rossby waves caused by enhanced tropical convection over the eastern Indian Ocean toward the South China Sea. In the second half of winter 2020/21, the enhanced convection shifted eastward to the Philippine Sea. The subsequent anticyclonic anomaly changed its position to the south of Japan, which was similar to the western Pacific (WP)-like teleconnection pattern, causing warmer conditions over East Asia. The composite analysis indicated that the anomalous anticyclone over the southeastern Tibetan Plateau corresponding to the SAJ pattern emerged simultaneously with intensification of convection over the South China Sea. Half of the cases of the WP-like pattern have been accompanied by enhanced convection over the Philippine Sea. The different circulation patterns were reproduced by prescribing the heat source over the South China Sea and Philippine Sea to the linear baroclinic model. Moreover, the vorticity budget analysis suggested that the presence of upper-tropospheric convergence of winds to the southeast of the Tibetan Plateau seen in the climatology is conceivable for the in situ localized anomalous circulation constituting the SAJ pattern due to vortex stretching effects.

Estimating relative abundance of kawakawa (Euthynnus affinis Cantor, 1849) landed in eastern indian ocean using catch and effort data

Kawakawa (Euthynnus affinis) is a neritic tuna commodity with high economic value, especially for coastal states such as Indonesia. However, there is a lack of information about kawakawa abundance in the Eastern Indian Ocean. This research aims to estimate the relative abundance of kawakawa using catch and effort data, which is often used as a method in fisheries stock assessments. The size distribution of kawakawa was also analyzed in this study. The data was collected through daily monitoring from 16 landing sites along the Fisheries Management Area (FMA) 572 to 573 from 2015 to 2021. The data recorded included catch, day of fishing, fishing gear, and biological data (length and weight). The annual catch per unit of effort (CPUE) analysis of kawakawa reached its maximum in 2018, while the minimum value occurred in 2015. Furthermore, the monthly CPUE demonstrated that the highest catch occurred during the observation years in February and March. The highest catch proportion of kawakawa reached 87.21% in 2017. Finally, the gross tonnage (GT) of the gear showed the most significant factor in the catch.

Trends of Indonesia’s bigeye tuna longline fisheries in the Eastern Indian Ocean: Catch per unit effort and length distribution

Bigeye tuna, Thunnus obesus (Lowe, 1839), is one of the primary target species for Indonesian tuna longliners operated in the eastern part of the Indian Ocean. However, the fishing trend and biological information are still scarce despite their importance in developing harvest strategy in the region. The study provides nominal catch per unit effort (CPUE) and length compositions of bigeye tuna caught by the Indonesian tuna longliners from the area. Data were obtained from records made by the onboard scientific observers assigned by the Research Institute for Tuna Fisheries (RITF) from 2006 to 2021. The data covers records from 3180 longline settings in 118 fishing trips in which more than 4 million hooks deployed. The fishing efforts were distributed between 0-35°S and 75-130°E, with 10 to 15 hooks between floats. The highest CPUE was 0.29±0.05 fish per 100 hooks in 2014, and the lowest was 0.09±0.05 fish per 100 hooks in 2021. From 8150 fish measurements in 2006 to 2021, the average size was 117.66±24.13 cm FL, and the dominant size class was 120–130 cmFL. While the average size of BET shows an increasing trend the CPUEs were declining.

Phylogeography of Long-spined Sea Urchin Diadema setosum Across the Indo-Malay Archipelago.

Widely distributed, broadcast-spawning Diadema sea urchins have been used as model invertebrate species for studying the zoogeography of the tropical Indo-Pacific. So far, the Indo-Malay archipelago, a wide and geographically complex maritime region extending from the eastern Indian Ocean to the western Pacific Ocean, has been under-sampled. This study aims to fill this sampling gap and uncover the phylogeographic structure of the long-spined sea-urchin D. setosum in the central Indo-West pacific region. D. setosum samples (total N = 718) were collected in 13 sites throughout the Indo-Malay archipelago. We sequenced over 1157 bp of COI gene. The Phylogeographic structure was derived from pairwise ФST estimates using multidimensional scaling and hierarchical clustering analysis; biogeographic hypotheses were tested by AMOVA; genetic relationships between haplotypes were summarised in the form of a minimum-spanning network; and pairwise mismatch distributions were compared to the expectations from demographic and spatial expansion models. All samples from the Indo-West Pacific were of the previously uncovered D. setosum-a lineage. Phylogeographic structure was evident: the Andaman Sea population and the northern New Guinea population were genetically distinct. Subtler but significant haplotype-frequency differences distinguished two populations within the Indonesian seas, distributed in a parapatric-like fashion. The phylogeographic partition observed was insufficiently explained by previous biogeographic hypotheses. The haplotype network showed a series of closely related star-shaped haplogroups with a high proportion of singletons. Nucleotide-pairwise mismatch patterns in the two populations from the Indonesian seas were consistent with both demographic and spatial expansion models. While geographic barriers to gene flow were inferred at the western and eastern extremities of the Indo-Malay archipelago, the subtler parapatric pattern observed within the Indonesian seas indicated restriction in gene flow, in a fashion that can hardly be explained by geographic isolation given the dynamic current systems that cross this region. Our results thus raise the hypothesis of subtle reproductive isolation between ecologically incompatible populations. While the coalescence pattern of the Andaman-Sea population suggested demographic stability over evolutionary timescales, that of the two populations from the Indonesian seas indicated recent population expansion, possibly linked to the rapid changes in available D. setosum habitat caused by sea-level oscillations in the late Pleistocene. The phylogeographic patterns observed in this study point to likely allopatric differentiation in the central Indo-West Pacific region. Genetic differences between populations were likely reinforced during interglacials by some form of reproductive isolation.

Biases and teleconnections in the Met Office Global Coupled Model version 5.0 (GC5) – insights for seasonal prediction and Australia

The Australian Bureau of Meteorology (The Bureau) has been involved in the package testing and assessment process of the UK Met Office Global Coupled Model Version 5.0 (GC5) configuration. GC5 will underpin the Met Office’s next seasonal prediction system, global coupled numerical weather prediction (NWP) system and Earth System Model. It will also likely be the next version of The Bureau’s seasonal prediction system, and the version to replace the global atmosphere-only NWP system to be the first global coupled NWP system at The Bureau. The GC5 configuration includes a new sea-ice model and substantial updates to almost all areas of model physics. We have evaluated the present-day climate simulation, and compared it to observations and with previous versions GC4 and GC2. Our assessment focuses on the climate mean state and variabilities relevant to Australian seasonal prediction, including the El Niño–Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), the Southern Annular Mode and the Madden–Julian Oscillation. Notably, in comparison to its predecessor (GC4), GC5 shows significant improvements in the eastern Pacific mean state but a slight degradation in the Indian Ocean in terms of the mean state and variability. These and other results provide us with early insights of the potential performance of the next sub-seasonal or seasonal forecast system. Longstanding issues in the seasonal prediction system associated with the equatorial eastern Indian Ocean biases and an overactive ENSO and IOD will likely remain; however, improvements over the eastern equatorial Pacific in GC5 hold promise of improved prediction skill of ENSO and its teleconnections.

Evidence of likely foraging by pygmy blue whales in the Timor Trough during the late austral winter and early austral spring

Understanding the behavioural context of wildlife movement patterns is imperative to the conservation of migratory species like cetaceans. The traditional model of baleen whale migration entails uninterrupted journeys performed throughout extended periods of fasting, during which individuals sustain the enormous costs of travelling from the poles to the tropics only from energy reserves acquired prior to departure. However, this ‘feast and famine’ paradigm is being challenged by increasing observations of supplemental feeding events along whale migratory routes. In this context, identifying the location of migratory stopovers is key to managing cetacean populations, particularly in data-poor ecosystems subject to changing ocean conditions. We report on likely foraging activity by migrant pygmy blue whales Balaenoptera musculus brevicauda in the Timor Trough (ca. 9.5° S, 126° E), a deep-water habitat south of the species’ presumed breeding grounds. Using photo-identification and generalised additive modelling, we analysed visual sightings collected aboard seismic vessels operating off Timor-Leste in 2007-2008 and demonstrate that (1) whales engage in surface behaviours suggestive of active feeding, (2) some individuals remain within the region for more than 1 d, and (3) whale presence is significantly associated with predictably high chlorophyll a concentrations. Despite previous efforts to examine pygmy blue whale movements at low latitudes using long-term satellite telemetry, knowledge of the species’ behavioural ecology in the tropics remains limited. Our results lend support to previously untested hypotheses about the possible use of the Timor Trough as a foraging site by eastern Indian Ocean pygmy blue whales during the late austral winter and early austral spring.

Influence of Madden–Julian Oscillation on Precipitation over the Tibetan Plateau in Boreal Summer

The influence of the Madden–Julian oscillation (MJO) on precipitation over the Tibetan Plateau (TP) during boreal summer is investigated using observational and reanalysis data during 1980–2020. The results show that summer precipitation over most areas of the eastern TP increases (decreases) in MJO Phases 1–2 (5–6), especially when the eastward-propagating MJO active convection is located over the Indian Ocean (Western Pacific) in Phase 2 (6). The most significant negative precipitation anomalies in Phase 4 (8) are located over the southern (northeastern) TP. Moreover, MJO has a relatively weakened effect on the TP summer precipitation in Phases 3 and 7 when its convection migrates to the eastern Indian Ocean and the western–central Pacific, respectively. The MJO-phase dependence of the TP summer precipitation anomalies is closely associated with the anomalous atmospheric circulation and evolution of the horizontal moisture flux convergence directly induced by MJO. When the MJO convection centers are located over the western Indian Ocean and the Pacific, high-level anticyclonic and low-level cyclonic anomalous circulations over the TP are excited. In contrast, when MJO locates over the Indian Ocean and the Maritime Continent, its diabatic heating can inspire high-level cyclonic and low-level anticyclonic circulation anomalies over the TP. The vertical motions and moisture transport from the Bay of Bengal caused by the MJO-excited large-scale circulation can modulate the TP summer precipitation. This study advances the understanding of the TP intraseasonal variability.

ENSO–IOD Inter‐Basin Connection Is Controlled by the Atlantic Multidecadal Oscillation

AbstractThe interactions between El Niño‐Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) are known to have great implications for global climate variability and seasonal climate predictions. Observational analysis suggests that the ENSO–IOD inter‐basin connection is time‐varying and related to the Atlantic Multidecadal Oscillation (AMO) with weakened ENSO–IOD relationship corresponding to AMO warm phases. A suite of Atlantic pacemaker simulations successfully reproduces the decadal fluctuations in ENSO–IOD relationship and its link to the AMO. The warm sea surface temperature (SST) anomalies associated with the AMO drive a series of Indo‐Pacific mean climate changes through tropical‐wide teleconnections, including the La Niña‐like mean SST cooling over the central Pacific and the deepening of mean thermocline depth in the eastern Indian Ocean. By modulating ocean–atmosphere feedback strength, those mean state changes decrease both ENSO amplitude and the Indian Ocean sensitivity to ENSO forcing, therefore decoupling the IOD from ENSO.

A northward range extension of Thysanophrys papillaris (Actinopterygii: Scorpaeniformes: Platycephalidae) to Taiwan

The smallknob flathead, Thysanophrys papillaris Imamura et Knapp, 1999, is redescribed based on six specimens collected from southern Taiwan, which constitutes a northward range extension of the species [previously recorded from the Andaman, Timor, and Arafura seas (eastern Indian Ocean), and Nha Trang, Vietnam (western Pacific Ocean)]. Thysanophrys papillaris is distinguished from all congeneric species in having a combination of 11 second dorsal-fin rays, 12 anal-fin rays, 58–75 scale rows below the lateral line (slanting downward and forward), a longer snout (snout length / orbital diameter ratio 1.1–1.3), 1 or 2 small papillae on the eye, the upper iris lappet with short branches, a single preorbital spine and 3–5 suborbital spines. Previously suggested intraspecific variation in the number of eye papillae is confirmed.

Different ENSO Teleconnections over East Asia in Early and Late Winter: Role of Precipitation Anomalies in the Tropical Indian Ocean and Far Western Pacific

Abstract This study aims to better understand the ENSO impacts on climate anomalies over East Asia in early winter (November–December) and late winter (January–February). In particular, the possible mechanisms during early winter are investigated. The results show that ENSO is associated with a Rossby wave train emanating from the tropical Indian Ocean toward East Asia (denoted as tIO-EA) in early winter. This tIO-EA wave train in El Niño (La Niña) is closely related to a weakening (strengthening) of the East Asian trough, and thereby a weakened (strengthened) East Asian winter monsoon and warm (cold) temperature anomalies over northeastern China and Japan. By using partial regression analysis and numerical experiments, we identify that the formation of tIO-EA wave train is closely related to precipitation anomalies in the tropical eastern Indian Ocean and western Pacific (denoted as eIO/wP). In addition, the ENSO-induced North Atlantic anomalies may also contribute to formation of the tIO-EA wave train in conjunction with the eIO/wP precipitation. The response of eIO/wP precipitation to ENSO is stronger in early winter than in late winter. This can be attributed to the stronger anomalous Walker circulation over the Indian Ocean, which in turn is caused by higher climatological SST and stronger mean precipitation state in the Indian Ocean during early winter.

Winter surface air temperature variation over Pakistan during 1970–2014 and its principal drivers in the tropical ocean

This study examined the leading modes of Dec–Feb (DJF) month's surface temperature (DJFTs) and associated mechanisms of the most significant drivers affecting temperature variability during the season from 1970 to 2014. EOF1 of DJF temperature reveals uniform spatial patterns over most of Pakistan, except extreme north, accounting for 84.38% of the total variance. The typical warm (cold) years were 1970, 1981, 1988, 1990, 1993, 2004, 2006, 2009, 2010 (1972, 1974, 1975, 1984, 2008, 2012). Favorable atmospheric conditions for warm temperature events (DJFTs) in Pakistan is an anomalous anticyclone spread over northeast Pakistan to Tibet at low to upper levels. This condition is controlled by the south and western part, of which there are significant southerly and convergent flows at low level with ascending motion over the study area. Further, examination revealed a close relationship of warm DJFTs with Western Indian Ocean warming and Eastern Indian Ocean indices but insignificant relation with the Nino3.4 index. Ocean warming related to Dipole Mode Index over eastern Indian Ocean (DMIE) is more influential (r = 0.51) than over the western Indian Ocean (DMIW) index (r = 0.37). The Ocean warming related to DMIE (EIOW), especially in Nov-Dec-Jan (NDJ) season, forced a significant ascending motion locally and then induced warm DJFTs-associated circulation pattern, propagating northward to Europe. By the dynamic diagnosis, the adiabatic and diabatic heating for the warm DJFTs is not remarkable. However, the horizontal temperature advection is positive and significant over most parts of Pakistan, both in the DJF and NDJ season, from the surface to the top of the troposphere. It suggests that the warm temperature advection is the possible prominent way of the EIOW on the warm DJFTs.

New record of the Armored Gurnard Satyrichthys laticeps (Schlegel, 1852) (Scorpaeniformes: Peristediidae) from Java South Sea (Eastern Indian Ocean)

Abstract. Andeimida A, Wiadnya DGR, Hardiyan FZ. 2022. New record of Satyrichthys laticeps (Schlegel, 1852) (Scorpaeniformes: Peristediidae) from Java South Sea (Eastern Indian Ocean). Indo Pac J Ocean Life 6: 74-79. Armored gurnard Satyrichthys laticeps (Schlegel, 1852) was originally described by H. Schlegel in 1852 based on a specimen collected by E. A. Forsten from Ambon. S. laticeps belongs to the family Peristediidae and is known to be the fourth oldest persitediid fish ever described after Peristedion cataphractum (Linnaeus, 1758), P. orientale Temminck & Schlegel, 1843, and S. moluccensis (Bleeker, 1850). S. laticeps is known to have a wide distribution in temperate and tropical Indo-Pacific, but its records in Indonesian waters are still very limited. So far, only three recorded specimens of S. laticeps have been collected from Indonesian waters. A single Satyrichthys specimen was collected from a market vendor at Pondokdadap Fishing port in November 2022 and preserved under the PDD 2211-01 (341 mm SL) label. Based on its morphometrical characteristics and measurements, the specimen of Satyrichthys found in Pondokdadap was characterized as S. laticeps by examining the possession of the antrorse spines on the caudal peduncle, four lip barbels, and two chin barbels on each side of the head, asymmetrical parietal bones, and no distinct markings on the dorsal fin. This study provides a new record of S. laticeps existence in the Java South Sea after a single specimen was collected from off the south coast of Java and Bali, Indonesia (BMNH 1987.1.23.73, 291 mm SL) in 1987.