Description of Ophthalmonema diodontis gen. et sp. n. (Nematoda: Cystidicolidae), a parasite of the eye and surrouding tissues of porcupinefishes (Diodon spp.), with a key to cystidicolid genera.

The present study investigated the reproductive biology of blue mackerel (Scomber australasicus) off southern and eastern Australia and assessed the suitability of the Daily Egg Production Method (DEPM) for future stock assessment. This analysis revealed that S. australasicus is a serial spawner with asynchronous oocyte development and indeterminate fecundity. S. australasicus spawns between November and April off southern Australia and between July and October off eastern Australia. In southern Australia, ~50% of males and females were mature at 236.5 and 286.8 mm fork length (FL), respectively. Size at ~50% maturity could not be estimated reliably for eastern Australia owing to the smaller proportion of mature fish in samples. Mean spawning frequencies ranged from 2 to 11 days off southern Australia. Batch fecundity was related to fish size and mean batch size was 69 894 ± 4361 oocytes per batch and 134 oocytes per g of weight. The timing and duration of the spawning season, size at maturity, spawning frequency and batch fecundity of S. australasicus off southern Australia were consistent with those of S. japonicus in the northern Pacific Ocean. The present study’s estimates of adult reproductive parameters of S. australasicus off southern Australia were suitable for the application of the DEPM for estimating spawning biomass. Collecting representative samples of mature fish from waters off eastern Australia during the spawning season is a high priority for future stock assessment of this species.

The trypanorhynch cestode family Pterobothriidae Pintner, 1931 is revised. Valid species of the genus Pterobothrium Diesing, 1850 are defined. Ten species of pterobothriid cestodes, including five new species, are described from elasmobranchs taken in waters off Australia, the Indian Ocean, the Atlantic coast of North America, and in the S Atlantic off Senegal, West Africa. Six of the species, P. acanthotruncatum, P. lintoni, P. lesteri, sp. nov., P. pearsoni, P. southwelli, sp. nov., and P. australiense, sp. nov., are described from fishes in Australian waters and the Indian Ocean. The armature of Pterobothrium heteracanthum Diesing, 1850 is redescribed using light and scanning electron microscopy. New intermediate hosts, locality records, and synonyms are provided for P. crassicolle Diesing, 1850 from Atlantic coastal waters of North and South America. Details of the entire armature of Pterobothriurn crassicolle Diesing, 1850 from Micropogonias furnieri (Desmarest) from Rio de Janiero are included. Two new species of Pterobothrium, P. kingstoni, sp. nov., and P. senegalense, sp. nov., are described from dasyatid rays in waters of the Atlantic Ocean. P. kingstoni, sp. nov., from dasyatid rays taken in coastal waters off New England and Chesapeake Bay, Virginia, is distinguished by the presence of a wide band of hooks on the external face of the tentacle, a single row of 4 intercalary hooks, absence of a basal swelling and special armature and by a transverse base on hooks 4(4′) of each principal metabasal row. Pterobothrium senegalense, sp. nov., is described from Dasyatis centroura from Gorbe, Senegal, West Africa, and is distinguished by 3 intercalary rows of hooks that run over onto the external tentacular face but never occupy the midline, by the size and position of hooks in the first intercalary row, and position of the first intercalary row relative to the second and third rows. Pterobothrium southwelli, sp. nov., P. lesteri, sp. nov., and P. pearsoni are described from teleosts in the Indian Ocean. P. southwelli, sp. nov., is distinguished from congeners by a distinctive basal armature and prominent band of hooks on the external surface, a single intercalary row, uncinate hooks l(1′) in all metabasal principal rows, and absence of dentate hooks from the metabasal rows. P. lesteri, sp. nov., is unique in the combination of a basal row of 3 small hooks, a band of hooks, a single intercalary row of 3–4 hooks and in the possession of hooks 4(4′) with dentate tips and hooks 5(5′) with filamentous tips. P. pearsoni differs in possessing a band of hooks and 2 rows of intercalary hooks per principal row, basal armature restricted to the external surface, and uncinate hooks l(1′) combined with dentate hooks 4(4′)–5(5′) in all metabasal rows. Three species from Australian waters, P. lintoni (MacCallum, 1916), P. australiense, sp. nov., and P. acanthotruncatum, lack a well-developed band of hooks on the external face of the metabasal armature. P. lintoni (MacCallum, 1916), the senior synonymn of P. malleum MacCallum, 1916) and P. dasybati Yamaguti, 1934, is described from types and compared with new specimens from the Woods Hole region (USA) and Australia. New host records for adults and plerocerci of P. lintoni are reported from Australian waters off Queensland and South Australia. Pterobothrium chaeturichthydis (Yamaguti, 1952) is considered a synonym of P. lintoni. P. australiense, sp. nov., from Pristis zijsron near Townville, Queensland, differs from congeners in the possession of slender falcate hooks 1(1′), notched tips of hooks 5(5′), a single intercalary row of 3 hooks, and total absence of a band of hooks on the external tentacular face. P. australiense, sp. nov., is similar to P. acanthotruncatum but has falcate hooks at the start of each principal row, lacks the pairs of satellite microhooks on the external face adjacent to the principal rows and possesses a band of microhooks in the basal region of the external face of the tentacle. P. acanthotruncatum is reported from new hosts in Australia and from Sri Lanka and India. A key to the 12 currently recognised species of pterobothriids is provided.

Pronounced spatial gradients were observed in trace element concentrations (Cd, Co, Cu, and Ni) in nearshore surf zone (<100 m offshore) and coastal (5−45 km offshore) waters off Baja California, Mexico. The ranges of metal concentrations in those waters were 0.034−0.26 nM for Cd, 0.022−0.59 nM for Co, 0.93−3.6 nM for Cu, and 3.6−6.4 nM for Ni. Metal concentrations exhibited offshore gradients, with the highest levels nearshore. Metal:salinity, metal:nutrient, and metal:metal relationships indicated that the relatively high nearshore concentrations were caused by upwelling (Cd and Ni) and by benthic particle resuspension and diagenetic remobilization (Co and Cu). The relatively low offshore concentration levels appeared to be caused, in part, by the intrusion of oceanic waters from the North Pacific Central Gyre, as evidenced by similarities in the molar ratios of Ag:Cu in coastal waters off Baja California (9.0 × 10-3) and in subtropical oceanic waters off central Mexico (9.6 × 10-3). This was also consi...

Mapping the fishing intensity in the coastal waters off Guangdong province, China through AIS data

Nineteen species of the rare polychaete genus Heterospio are reported, 15 of which are new to science. The status of H. longissima Ehlers, 1874, the type-species, is reviewed. The specimens examined are from several locations in the North Atlantic Ocean, Gulf of Mexico, Caribbean Sea, off Br azil, the Indian Ocean, the Pacific Ocean off California, New Zealand, Australia, and the South China Sea. Deep-water samples from the western North Atlantic Ocean collected by the late Drs. H.L. Sanders and R.R. Hessler that were reported by Hartman as H. longissima were re-examined and referred to two new species, H. hartmanae n. sp. (abyssal depths, New England to Bermuda transect) and H. guiana n. sp. (bathyal depths off Suriname). Other materials from the Sanders/Hessler North Atlantic collections were also examined and referred to two additional species, H. canariensis n. sp. (deep water off Canary Islands) and H. southwardorum n. sp. (Bay of Biscay) as well as H. cf. reducta from off SW Ireland in bathyal depths. New collections from the North Atlantic region include additional materials of H. hartmanae n. sp. (deep water off the Mid-Atlantic and SE USA), H. aruba n. sp. (Caribbean Sea), H. bathyala n. sp. (deep water off SE USA), and H. dibranchiata n. sp. (deep water, Gulf of Mexico). Heterospio paulolanai n. sp. is from shelf depths off southeastern Brazil. Heterospio knoxi n. sp. is from the North Island of New Zealand, H. ehlersi n. sp. is from the Gulf of Thailand, in the South China Sea, H. bidentata n. sp. is described from deep water in the Coral Sea off eastern Australia, and H. alata n. sp. and H. brunei n. sp. are described from deep water off the Island of Borneo in the South China Sea. Heterospio africana n. sp. and H. antonbruunae n. sp. are described from off east Africa in the Mozambique Channel. New records and descriptions of H. catalinensis, H. indica, and H. peruana are presented. The 15 new species reported here nearly triple the number of previously known species of Heterospio, with 23 species now recognized. All known species are tabulated and compared.

The study is based on physicochemical parameters (pH, DO, and salinity) and dissolved trace elements (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, and Cd) of Uppanar River water (RW) and surface and bottom coastal waters (CW) off Cuddalore, southeast coast of India in 56 samples collected during 2001. High concentration of Fe and Mn in RW and CW indicates enrichment above the normal level. Physicochemical parameters do not exhibit significant relationship with trace metals. Enrichment of Pb is due to external input and excess level of Cu, Pb, Zn in RW and Cr, Cu, Ni, Pb in CW is identified. Fe-Mn oxides are the chief scavengers of trace elements in both the aquatic environments and it is supported by geochemical, statistical and comparative studies. The results signify that industrial growth has affected the aquatic environments and regular monitoring will help to adopt stringent pollution control measures for better management of the aquatic region.

In order to determine the origins of dissolved inorganic nutrients and dissolved organic matter in coastal waters off Jeju Island, Korea, we measured the concentrations of 222Rn, nutrients, fluorescent dissolved organic matter (FDOM), and dissolved organic carbon in coastal waters during September 2016 and October 2017. The lower salinity waters occurring in the southern coastal waters off Jeju (SCW) were characterized by higher nutrients and humic-like FDOM, while those in the western coastal waters off Jeju (WCW) showed no trend. A significant negative correlation between salinity and 222Rn in the SCW (r2 = 0.62, n = 7 for 2016; r2 = 0.56, n = 14 for 2017) indicates that freshwaters occurring in the SCW originate from fresh groundwater. However, depleted 222Rn activities in the fresh surface waters of the WCW indicate that those in the WCW originate mainly from the remote Changjiang diluted water. In general, the coastal ecosystem in the SCW is characterized by the dominance of brown seaweeds, and the WCW is by scleractinian corals. Our results imply that high nutrient concentrations in the SCW provide favorable conditions for the growth of seaweeds, while relatively low nutrient concentrations and high FDOM concentrations in the WCW provide favorable conditions for survival of corals.

The present study is focused on understanding long-term trend in distribution of chlorophyll-a and its association with water quality parameters in coastal waters of northwestern Bay of Bengal. In situ observations were carried out in monthly frequency during January 2009 to March 2017 at two ecologically important study sites, off Gopalpur and off Visakhapatnam. A bimodal distribution of chlorophyll-a was observed off Gopalpur with primary and secondary peak during pre- and post-monsoon, respectively. In contrast, maximum chlorophyll-a concentration was noticed in monsoon irrespective of sporadic higher magnitudes during pre-monsoon in coastal waters off Visakhapatnam. The pivotal role of river influx and coastal upwelling was discerned in enriching coastal waters off Gopalpur with macronutrients and in turn on chlorophyll-a distribution. Adequate availability of silicate signified favorable condition for diatom growth in coastal waters off Gopalpur leading to preponderance. Influence of coastal upwelling and nutrient-controlledgrowth of phytoplankton was observed in coastal waters off Visakhapatnam.

Unprecedented large-scale harmful algae blooms (HABs) were reported in coastal waters off the south-eastern coast of Hokkaido, Japan, in mid-to-late September 2021, about a month after very intense and extensive marine heatwaves subsided. To understand the physical–biological processes associated with development of the HABs, we conducted analyses via a combination of realistic ocean circulation models, particle-tracking simulations, and satellite measurements. The satellite-derived chlorophyll concentrations (SCCs) and areal extent of the high SCCs associated with the HABs were the highest recorded since 1998. More specifically, the extent of SCCs exceeding 5 or 10 mg m−3 started to slowly increase after 20 August, when the marine heatwaves subsided, intermittently exceeded the climatological daily maximum after late August, and reached record-breaking extremes in mid-to-late September. About 70% of the SCCs that exceeded 10 mg m−3 occurred in places where water depths were &lt;300 m, i.e., coastal shelf waters. The high SCCs were also tightly linked with low-salinity water (e.g., subarctic Oyashio and river-influenced waters). High-salinity subtropical water (e.g., Soya Warm Current water) appeared to suppress the occurrence of HABs. The expansion of the area of high SCCs seemed to be synchronized with the deepening of surface mixed layer depths in subarctic waters on the Pacific shelves. That deepening began around 10 August, when the marine heatwaves weakened abruptly. However, another mechanism was needed to explain the intensification of the SCCs in very nearshore waters off southeast Hokkaido. Particle-tracking simulations based on ocean circulation models identified three potential source areas of the HABs: the Pacific Ocean east of the Kamchatka Peninsula, the Sea of Japan, and the Sea of Okhotsk east of the Sakhalin Island. Different processes of HAB development were proposed because distance, time, and probability for transport of harmful algae from the potential source areas to the study region differed greatly between the three source areas.

The optical properties of coastal (case 2) waters off Paradip and off Visakhapatnam, Bay of Bengal, east coast of India are studied. The relationship of diffused reflectance R (0 - ) with the ratio of backscattering to absorption coefficient ( b b / a ) and b b /( a + b b ) are investigated. Analysis of the bulk data shows that R (0 - ) varies linearly with b b / a [i.e. R (0 - )= f 1 ( b b / a )] with a proportionality constant f 1 =0.22. Similarly, R (0 - ) varies linearly with b b /( a + b b ) [i.e. R (0 - )= f 2 ( b b /( a + b b ))] with a proportionality constant f 2 =0.27. The result indicates that the present empirical relationships can be used for prediction of reflectance spectra in case 2 waters with standard error of estimation ranging from 0.01 to 0.02. The empirical relationship between R (0 - ) and b b / a obtained in the case 2 waters off Paradip is examined in case 2 waters off Visakhapatnam, Back River and Appomattox River readings. The relationship between solar zentih angle and f 1 has been investigated. The results do not show any significant variation of f 1 with respect to cosine of solar zenith angle.

In recent years, the spectacular massive green tide of Ulva prolifera has become a recurrent phenomenon appearing every summer in the coastal waters off Qingdao (Yellow Sea, China), attracting the attention of scientists and local government. Based on multidisciplinary data collected during summer and winter, this study focuses on the hydrological characteristics and regional biogeochemical processes in coastal waters off Qingdao. The results show that the boundary of the Yellow Sea Cold Water Mass (YSCWM) can reach the Qingdao coastal region in summer and is locally raised to the upper layers to form coastal upwelling beyond tidal mixing and favorable wind. The regional summer upwelling off the Qingdao coast effectively enriches the nutrient concentrations in the upper water column and thus promotes growth of phytoplankton but reduces the dissolved oxygen (DO) concentration and pH value in the bottom. The regional summer upwelling off Qingdao coast may facilitate the growth and regional blooming of the U. prolifera that migrate to this region with the southerly wind. Additionally, the effects of the front on the aggregation of U. prolifera may be significant. In winter, the Yellow Sea Warm Current (YSWC) extends and spreads along the offshore region off the Subei Shoal towards the Qingdao coastal sea. This tongue-shaped warm water meets the cold coastal water off Qingdao, which leads to the formation of a physical front. As a consequence, remarkable fronts of nutrient and chlorophyll a (Chl a) also form between the shoreward warm water and the cold coastal water. This study increases the understanding of the interactions between the regional physical, chemical, and biological processes off the Qingdao coast.

Factors influencing the distribution of 223Ra and 224Ra in the coastal waters off Tanggu and Qikou in Bohai bay

In the coastal areas of Wakasa Bay, the Japan Sea—an observation network for fisheries and a simulation system of coastal currents with a high-resolution numerical model—revealed intensification of current in summer around Cape Echizen. The 2012–2014 current data collected by mooring observations off Takasu, near Cape Echizen, showed that the current’s speed exceeded 40 cm s−1 for more than 5 days around July and August each year. In addition, the 2014 current data collected by a research vessel indicated that the first branch of the Tsushima Warm Current (FBTWC) flowed near the coast when the strong current with an increase of water temperature occurred in the upper layer of coastal waters off Takasu. Similarly, the simulation results revealed that the FBTWC variability caused intensification of the current in coastal waters near Cape Echizen. In addition, they showed that when the strong current was generated in coastal waters off Takasu, cold water accompanied by strong current expanded to coastal seas around Cape Echizen in the subsurface layer. From these results of the observations and the simulation, it was considered that the strong current in the coastal waters off Takasu in summer was attributed to the acceleration of the FBTC, which is accompanied by cold water expansion in the subsurface layer to the vicinity of the coast and contact of the FBTWC along the cold water edge with the coast.

Alkaline phosphatase activity at the southwest coast of India: A comparison of locations differently affected by upwelling

An integrated buoy-satellite based coastal water quality nowcasting system: India's pioneering efforts towards addressing UN ocean decade challenges