THE SEA-BIRDS OF THE SOUTHEAST COAST OF ARABIA

The present study of an upwelling area off the southeast coast of Arabia, between 52° and 60° E. is based primarily on observations on board the R.R.S, `Discovery’ during the International Indian Ocean Expedition. During oceanographic surveys off the Arabian coast from June to August 1963 and in early March and late May 1964 I made 234 counts of birds of about an hour each, the results of which have been used as an index of bird density. In this area, the only offshore islands known to be important to sea-birds are the Kuria Muria Islands, which were apparently at the centre of an upwelling area. The upwelling of cold water along the Arabian coast during the southwest monsoon from May to September greatly increases organic production in the sea, and large populations of organisms at every level of the food chain develop there. Previous work in Arabia and the Arabian Sea is reviewed. Little is recorded about the ecology of sea-birds there, but the composition of the fauna is quite well-known. The distribution of every sea-bird species recorded from 52° E. to 60° E., and within 200 miles offshore, is described, with particular reference to my own observations. Details are given of the distribution of common species during the southwest monsoon of mid-June-mid-August 1963 and in March and May 1964. Specimens collected on the `Discovery’ are recorded together with their measurements. Of 12 sea-bird species seen commonly off Arabia during the southwest monsoon in 1963, 11 were seen in late May 1964, but only five in March. There is certain evidence that two species have bred on the Kuria Muria Islands and suggestive evidence for a further three. Information on breeding seasons in the Arabian Sea is based on short visits to breeding colonies, mostly outside the breeding season, and on the plumage condition of specimens. Nevertheless, the sum of the evidence suggests that breeding is regular at the same time every year, and in most species seems to be in the northern summer. The food of sea-birds in the Arabian Sea, determined from stomach contents and visual observation, only serves to stress the lack of knowledge on this subject. A brief summary of feeding methods recorded by me suggests that they may be important in avoiding interspecific competition, for there seems to be little overlap. The density of sea-birds during the southwest monsoon 1963, expressed as the number of each species seen per hour, was analysed in relation to: (i) the sea surface temperature, which was inversely correlated with the zooplankton density from 0–200 m. (ii) the distance from the Kuria Muria Islands, the only likely breeding station; (iii) the distance from the nearest land which may have been important to land-tied sea-birds. All the abundant species were commonest close to land in the cool-water area and, with the exception of migrants from the southern hemisphere, most were concentrated around the Kuria Muria Islands in the centre of upwelling. A multiple analysis suggested that the islands were of real importance to some species. A separate analysis also demonstrated the existence of a correlation between sea-bird numbers and the abundance of zooplankton from 0–200 m. depth, but not the abundance of zooplankton at the sea surface. During the southwest monsoon the southeast Arabian coast is inhabited by a distinctive cool-water fauna within the tropical zone of the Indian Ocean. The high degree of endemism, the high proportion of migrants, including some from the southern hemisphere, and the absence of most pantropical species, suggest that the marked changes in the environment off southeast Arabia demand considerable adaptation. A brief discussion of the possible origins of the Arabian coast sea-bird fauna shows that it is not typical of either a subtropical or a tropical community in other regions. The likelihood that sea-birds breed in the summer, the concentration of most species in the upwelling area at that time and their absence during the winter, clearly demonstrates the importance of the upwelling. However, the results of the analysis suggest that some species were concentrated around the Kuria Muria Islands in the centre of the upwelling because the islands had a real importance to them, possibly as a breeding station. The correlation between sea-bird density and zooplankton abundance in the top 200 m., but not at the surface, may be explained if sea-birds concentrate in areas of high productivity rather than in areas of abundant surface plankton, which is largely irrelevant as food.     

SEA-BIRD OBSERVATIONS OFF SOMALIA

The oceanography of the coastal waters of eastern Somalia was investigated by R.R.S. ‘Discovery’ during August and September 1964. The oceanographic findings are briefly described. Although upwelling was in progress north of 8^oN, plankton, sea-birds and other signs of a high rate of organic production were notably scarce. Previous knowledge of the marine ornithology of the Somali coast is poor and some unpublished notes ot ine late M. E. W. North are given in full. In 1964 both the warm Somali current and the upwelling area between Ras Mabber and Cape Guardafui supported few sea-birds, though they were largely different species. The only area with abundant sea-birds was at the boundary between the cool upwelled water and the warm water spreading from the Gulf of Aden. It is suggested that the former may sink before the final stages of the ecological succession are reached, so that food for sea-birds is scarce. Summaries of the distributions of each species are given and these are compared with previous observations.     

Extraordinary capture of a Randall's snapper Randallichthys filamentosus in the temperate south‐eastern Indian Ocean and its molecular phylogenetic relationship within the Etelinae

The capture of a rarely encountered Randall's snapper Randallichthys filamentosus (female, 587 mm fork length) from the upper continental slope (c. 350 m) off the south coast of Western Australia (c. 34·5° S; 122·5° E) in January 2014 represents its first record from the temperate Indian Ocean and a southern range extension. This record suggests that spawning of this predominantly tropical species may probably be occurring in the eastern Indian Ocean, considering the extensive, and unlikely, distance the progeny would have otherwise travelled from its typical distribution in the western and central Pacific Ocean.     

STORM-PETRELS OCEANODROMA SPP. IN THE INDIAN OCEAN

In the course of the International Indian Ocean Expedition two storm-petrels, thought to be Oceanodroma matsudairae and O. monorhis, were encountered in the western Indian Ocean in some numbers. Two specimens of each species were collected, monorhis in the Arabian Sea, matsudairae off N.W. Australia. O. matsudairae, which had not been recorded before from these waters, appeafed to be concentrated within 5° of the equator and the birds probably belonged to the spring-breeding population of Volcano Island. O. monorhis was found mostly in the Arabian Sea. Bulweria bulwerii, for which there was but one certain Indian Ocean record, was also encountered several times.     

Some considerations when comparing SABAP 1 with SABAP 2 data

Jouanin's Petrel Bulweria fallax mainly occurs in the western Indian Ocean. Prior to our study there were only two records from east of 82° E. We show that small numbers of Jouanin's Petrels are regular visitors to the eastern Indian Ocean, occurring to 15° N 90° E in the Bay of Bengal and 15° S 123° E off northern Australia. Although seasonal coverage is limited, they have been recorded east of 80° E from April–July and October–December, but not in February–March. Most sightings are from oceanic waters at least 20 km offshore where depths exceed 500 m.     

Using calls as an indicator for Antarctic blue whale occurrence and distribution across the southwest Pacific and southeast Indian Oceans

Understanding species distribution and behavior is essential for conservation programs of migratory species with recovering populations. The critically endangered Antarctic blue whale (Balaenoptera musculus intermedia) was heavily exploited during the whaling era. Because of their low numbers, highly migratory behavior, and occurrence in remote areas, their distribution and range are not fully understood, particularly in the southwest Pacific Ocean. This is the first Antarctic blue whale study covering the southwest Pacific Ocean region from temperate to tropical waters (32°S to 15°S). Passive acoustic data were recorded between 2010 and 2011 across the southwest Pacific (SWPO) and southeast Indian (SEIO) oceans. We detected Antarctic blue whale calls in previously undocumented SWPO locations off eastern Australia (32°S, 152°E) and within the Lau Basin (20°S, 176°W and 15°S, 173°W), and SEIO off northwest Australia (19°S, 115°E).In temperate waters, adjacent ocean basins had similar seasonal occurrence, in that calling Antarctic blue whales were present for long periods, almost year round in some areas. In northern tropical waters, calling whales were mostly present during the austral winter. Clarifying the occurrence and distribution of critically endangered species is fundamental for monitoring population recovery, marine protected area planning, and in mitigating anthropogenic threats.     

Life‐history traits of Encarsia guadeloupae,a natural enemy of the invasive spiralling whitefly Aleurodicus dispersus

On south‐west Indian Ocean islands, many crops and ornamental plants are threatened by the spiralling whitefly Aleurodicus dispersus (Hemiptera: Aleyrodidae), which is a polyphagous pest that is native to the Caribbean region. Aleurodicus dispersus causes economic damage to various crops on all the islands in the south‐west Indian Ocean. The hymenopteran parasitoid Encarsia guadeloupae (Hymenoptera: Aphelinidae) is a natural enemy of A. dispersus on the Caribbean islands. In this study, we assessed the geographical distribution of the parasitoid in La Réunion, an island in the south‐west Indian Ocean where the parasitoid was first observed in 2004. We also investigated its main life‐history traits. Field surveys indicated that the parasitoid is widespread in most of the low‐lying areas of the island and exhibits high parasitism rates on A. dispersus populations. At 25°C, E. guadeloupae adults had a mean longevity of 33.6 days, and its pre‐imaginal development required 23 days. The lower temperature threshold and thermal constant were estimated to be 7.9°C and 132 degree‐days, respectively. Females of E. guadeloupae preferred to deposit eggs in early rather than in late instars of A. dispersus, and oviposition rates were highest in the second larval instar. Females of E. guadeloupae were able to oviposit in larvae of other species of whiteflies found in La Réunion (Bemisia tabaci and Dialeurolonga simplex), although subsequent development of the parasitoid was not monitored. Finally, we discuss the potential use of E. guadeloupae for the control of whitefly populations on islands in the south‐west Indian Ocean.     

Revision of genus Melamphaes (Melamphaidae). II. Multi-Raker species: M. polylepis, M. falsidicus sp. nova, M. pachystomus sp. nova, M. macrocephalus, M. leprus

The second part of the publication is devoted to the Melamphaes species (family Melamphaidae), which are characterized by 20 and more rakers on the first gill arch, by seven soft rays in the ventral fin, by absence of a temporal spine, by 14–15 rays in the pectoral fin, and by 11 abdominal vertebrae. M. polylepis is characterized by circumtropical range (Atlantic Ocean, Indian Ocean, western and central Pacific Ocean). Newly described species M. falsidicus is described from the northern Atlantic Ocean, where it was sampled between 34°N and 58°N. Before, this species was defined as M. microps. Another newly described species, M. pachystomus, is described along the Peruvian Coast. M. macrocephalus is redescribed. This species inhabits the eastern tropical Pacific Ocean (approximately between 30°N and 23°S). One of the studied specimens of M. macrocephalus was characterized by larger body size (SL = 128 mm) than was described before for this species. M. leprus is known currently by single findings from the eastern tropical Atlantic Ocean (between 11°N and 4°S). This species was also found in the samples obtain in the Gulf of Guinea.     

A new genus of large hydrothermal vent‐endemic gastropod (Neomphalina: Peltospiridae)

Recently discovered hydrothermal vent fields on the East Scotia Ridge (ESR, 56–60°S, 30°W), Southern Ocean, and the South West Indian Ridge (SWIR, 37°S 49°E), Indian Ocean, host two closely related new species of peltospirid gastropods. Morphological and molecular (mitochondrial cytochrome c oxidase subunit I, COI) characterization justify the erection of G igantopelta gen. nov. within the Peltospiroidae with two new species, G igantopelta chessoia sp. nov. from ESR and G igantopelta aegis sp. nov. from SWIR. They attain an extremely large size for the clade Neomphalina, reaching 45.7 mm in shell diameter. The oesophageal gland of both species is markedly enlarged. Gigantopelta aegis has a thick sulphide coating on both the shell and the operculum of unknown function. The analysis of a 579‐bp fragment of the COI gene resulted in 19–28% pairwise distance between Gigantopelta and six other genera in Peltospiridae, whereas the range amongst those six genera was 12–28%. The COI divergence between the two newly described species of Gigantopelta was 4.43%. Population genetics analyses using COI (370 bp) of 30 individuals of each species confirmed their genetic isolation and indicate recent rapid demographic expansion in both species. © 2015 The Linnean Society of London     

BIOGEOGRAPHIC ANALYSIS OF THE ARMORED PLANKTONIC DINOFLAGELLATE CERATIUM IN THE NORTH ATLANTIC AND ADJACENT SEAS1

The distribution of the dinoflagellate genus Ceratium Schrank (Dinophyceae) in the North Atlantic and adjacent seas was studied by a combination of new observations on a large number of plankton samples collected from the northeastern Atlantic and North Sea, data from cruises off the east coast of North America and Caribbean Sea, and reports in the literature of the past 90 years. Seventy species were recorded, and their distribution was examined by several methods. Distribution maps were plotted for all species, and from these the ranges of temperature tolerance were derived. The 240 sets of data, which took the form of lists of species present in 5° latitude / longitude blocks obtained from the new work and the published material, were analyzed by clustering and ordination multivariate techniques using the programs Twinspan and Decorana. Analysis of the individual species showed that surface water temperature is the most important factor determining distribution and the number of species in a particular area. Warm water and /or low latitudes have many more species than cold waters and/or high latitudes. For example, at 5°N there are on average 23 species per block, whereas at 60° N there are only 8 species. On the basis of this work, the Ceratium species are divided into Group 1, Arctic-temperate species normally only found in water of less than 15°C; Group 2, cosmopolitan species, which are found virtually everywhere and are the species most likely to form blooms or “brown water”; Group 3, intermediate species, which extend into neither the coldest nor the warmest water; Group 4, temperate-tropical species, which have a lower temperature boundary of 5°–12° C; Group 5, warm-temperate-tropical species with a lower temperature boundary of 14°–15°C; and Group 6, tropical species, which are rarely found in water of less than 20° C. Analysis of the sample sites also confirmed the predominant influence of temperature, and the Atlantic Ocean was divided into four biogeographical zones of which the boundaries follow isotherms of surface water temperature. Zone 1 consists of the Arctic and subarctic area, with the southern boundary closely following the 10° mean annual temperature (MAT) line. Zone 2 is an intermediate or cold-temperate zone, of which the southern boundary follows the winter 10° C MAT isotherm or the similarly placed summer 15° isotherm. Zone 3 is the warm-temperate or subtropical zone, which is very broad. The southern boundary closely follows the 25°C summer isotherm. Zone 4 is the tropical zone, where water temperature is never likely to be much less than 23°C. These findings are discussed in relation to experimental work and environmental observations. We suggest that the genus Ceratium provides an excellent tool for defining ocean currents and temperature changes and may become of value in studies of global change.     

Occurrence and density of Halobates micans (Hemiptera: Gerridae) in the eastern South Indian Ocean

Two species of ocean skaters, Halobates germanus and Halobates micans, live in the tropical and subtropical waters of the Indian Ocean. From December 1992 to December 1993, Halobates was intensively sampled in the easternmost region of the South Indian Ocean (13–18.5°S, 114–121E°), from which there have been a small number of records of Halobates. No H. germanus was caught, but a total of 1190 H. micans were collected, with densities estimated at 13 900–28 100 individuals/km². This suggests that H. micans lives in the study area at high densities comparable to those in the Atlantic and the Pacific Oceans. We also discuss the possible effects of ocean currents and winds on the geographic distributions of the two Halobates species in the eastern South Indian Ocean.     

Increased intrusion of warming Atlantic water leads to rapid expansion of temperate phytoplankton in the Arctic

The Arctic Ocean and its surrounding shelf seas are warming much faster than the global average, which potentially opens up new distribution areas for temperate‐origin marine phytoplankton. Using over three decades of continuous satellite observations, we show that increased inflow and temperature of Atlantic waters in the Barents Sea resulted in a striking poleward shift in the distribution of blooms of Emiliania huxleyi, a marine calcifying phytoplankton species. This species' blooms are typically associated with temperate waters and have expanded north to 76°N, five degrees further north of its first bloom occurrence in 1989. E. huxleyi's blooms keep pace with the changing climate of the Barents Sea, namely ocean warming and shifts in the position of the Polar Front, resulting in an exceptionally rapid range shift compared to what is generally detected in the marine realm. We propose that as the Eurasian Basin of the Arctic Ocean further atlantifies and ocean temperatures continue to rise, E. huxleyi and other temperate‐origin phytoplankton could well become resident bloom formers in the Arctic Ocean.     

Species of righteye flounder <Emphasis Type="Italic">Samariscus leopardus</Emphasis> sp. nov. (Samaridae,Pleuronectiformes) from the Saya de Malha Bank (Indian Ocean)

The new species Samariscus leopardus is described from one specimen caught at a depth of 159 m in the Indian Ocean, 11°22′ S, 61°42′ E. The species is easily distinguishable from the remaining species of the genus from a set of the following characteristics: the absence of a lateral line on both sides of the body, a short ventral fin, 42 vertebrae (9 trunk and 33 caudal), 5 rays of pectoral fin, and spotted coloration. Other morphological specific features, including topography of sensory canals of the head, are described.     

Distribution of tintinnid species from 42° N to 43° S through the Indian Ocean

Taking advantage of the transfer of the Italian R/V “Italica” from Italy to New Zealand for the Italian Research Expedition in the Antarctic, surface sampling of plankton was carried out from 42°N to 43°S from 14 November to 16 December 2001. Collaboration between several Italian research groups resulted in the Mediterranean, Indian and Pacific Ocean Transect (MIPOT), aimed to merge oceanographic measurements with remotely sensed data and to study latitudinal changes in plankton communities. We present preliminary results on the tintinnids (abundance and species composition) along the MIPOT1 transect. Tintinnid distributions and food vacuole contents are discussed in relation to chlorophyll concentrations and contribution of phytoplankton size classes. Generally, chlorophyll concentrations were well below 0.5 mg m^?3 and tintinnid numbers were only a few tens per liter. Eighty-six tintinnid species belonging to 27 genera were recorded. Highest diversity and number of tintinnid species occurred in the warm-water regions, from the Mediterranean Sea to the Tropic of Capricorn. Shannon diversity index ranged from 1.0 (Tasman Sea) up to 2.9 (tropical Indian Ocean). Each of the oceanic provinces showed a well defined tintinnid assemblage, a tintinnid ‘fingerprint’ characterizing each area. Data are compared to previous records for the different areas and the persistence in time of typical tintinnid species is discussed.     

Revision of the genus <Emphasis Type="Italic">Melamphaes</Emphasis> (Melamphaidae): Part 3. Multirakered species: <Emphasis Type="Italic">M. suborbitalis,M. parini</Emphasis>, and <Emphasis Type="Italic">M. acanthomus</Emphasis>

In the third part of the revision of the genus Melamphaes Melamphaidae (Melamphaidae), we examine multirakered species (20 and more rakers at the first gill arch) with seven soft rays in the ventral fin that have a posttemporal (temporal) spine directed anteriorly-upwards, with 14–15 rays in the pectoral fin, and 11 (rarely 12) trunk vertebrae. M. suborbitalis inhabits the Atlantic Ocean (in the north up to 57°N, in the south, up to 40°S), the Indian Ocean (is known in its southwestern part), and the western part of the Pacific Ocean. There is no significant evidence on catches of this species in the eastern part of the Pacific Ocean. Apparently, M. suborbitalis is absent in the tropical waters of the oceans. Until recently, M. parini was known from the holotype caught in the Sea of Okhotsk. Two specimens of this rare species: from the central (the area of the Hawaiian Islands) and the northeastern part of the Pacific Ocean are reported. M. acanthomus is an endemic of the eastern part of the Pacific Ocean where it is known along the coasts of America from California to the northern coast of Chile (approximately between 33°N and 21°S).     

SEA-BIRD BREEDING SEASONS ON CHRISTMAS ISLAND,PACIFIC OCEAN*

Christmas Island, at 2° N, 157° W in the Central Pacific Ocean, supports 18 breeding species of sea-birds. Data on the breeding seasons collected by the authors and other visitors to the island are analyzed in individual species accounts. Population estimates are given, the distribution of each species on the island is outlined, and for some species information on the sexual and moult cycles of marked individuals is presented. The Discussion concerns the ultimate and proximate factors controlling breeding seasons and the role of social factors in maintaining breeding synchrony in sea-birds, the diversity of the breeding regimes exhibited on Christmas Island (summary and analysis in Fig. 2 and Table 5), and comparison of these regimes with those found in the birds of Ascension Island and the Galapagos Archipelago.     

THE MARINE DIATOM ETHMODISCUS REX: ITS MORPHOLOGY AND OCCURRENCE IN THE PLANKTON OF THE SARGASSO SEA1,2

Living cells of the diatom Ethmodiscus rex (Rat-Iray) Wiseman & Hendey 1953 were found in the plankton of the southern Sargasso Sea. Apparently, this is the first report, of E rex from the plankton of the Atlantic Ocean. Scanning electron microscopy of peroxide-cleaned frustules revealed, some new morphological features for this species. When viewed, from inside the frustule, the puncta appear as rimmed pits. From outside the frustule, they appear to he shallow depressions with a small opening at the bottom. The so-called mucous tubules in the center of the valve were seen from the out side to be elongate slits and from the inside as obliquely directed flattened cylinders which cap the tubes.     

Habitat modelling of <Emphasis Type="Italic">Electrona antarctica</Emphasis> (Myctophidae,Pisces) in Kerguelen by generalized additive models and geographic information systems

Electrona antarctica is one of the most abundant mesopelagic fishes in the oceanic zone surrounding the Kerguelen Archipelago in the Indian sector of the Southern Ocean. Generalized additive models (GAM) combined with geographical information systems (GIS) were used to predict and map the abundance of this species according to three environmental variables: sea surface temperature, bathymetry and surface chlorophyll a. The model was applied on the Antarctic Polar Front in the eastern part of Kerguelen Archipelago. E. antarctica seems to be linked to areas presenting low chlorophyll a concentrations, depths greater than 500 m and temperatures lower than 5°C. The model was then applied to the Kerguelen’s plateau for three different years: 1998, 1999 and 2000. The position of Antarctic Polar Front and the intensity of an upwelling play an important role in the abundance variability of E. antarctica. Furthermore, the model allows the understanding of the habitat of E. antarctica and its trophic place in the pelagic ecosystem.     

Reef‐coral refugia in a rapidly changing ocean

This study sought to identify climate‐change thermal‐stress refugia for reef corals in the Indian and Pacific Oceans. A species distribution modeling approach was used to identify refugia for 12 coral species that differed considerably in their local response to thermal stress. We hypothesized that the local response of coral species to thermal stress might be similarly reflected as a regional response to climate change. We assessed the contemporary geographic range of each species and determined their temperature and irradiance preferences using a k‐fold algorithm to randomly select training and evaluation sites. That information was applied to downscaled outputs of global climate models to predict where each species is likely to exist by the year 2100. Our model was run with and without a 1 °C capacity to adapt to the rising ocean temperature. The results show a positive exponential relationship between the current area of habitat that coral species occupy and the predicted area of habitat that they will occupy by 2100. There was considerable decoupling between scales of response, however, and with further ocean warming some ‘winners’ at local scales will likely become ‘losers’ at regional scales. We predicted that nine of the 12 species examined will lose 24–50% of their current habitat. Most reductions are predicted to occur between the latitudes 5–15°, in both hemispheres. Yet when we modeled a 1 °C capacity to adapt, two ubiquitous species, Acropora hyacinthus and Acropora digitifera, were predicted to retain much of their current habitat. By contrast, the thermally tolerant Porites lobata is expected to increase its current distribution by 14%, particularly southward along the east and west coasts of Australia. Five areas were identified as Indian Ocean refugia, and seven areas were identified as Pacific Ocean refugia for reef corals under climate change. All 12 of these reef‐coral refugia deserve high‐conservation status.     

Length–weight relationships of three fish species from the Tibet reach of the Lancang River,China

Length‐weight relationships (LWRs) were determined for three fish species, Schizothorax lantsangensis (Tsao, 1964), Schizothorax lissolabiatus (Tsao, 1964) and Schizopygopsis anteroventris (Wu & Tsao, 1989), from the Tibet reach of the Lancang River, China (N 29°06′–31°30′, E 96°57′–98°38′). Specimens were collected in April and September 2017. The specimens were caught with drifting gillnets (mesh size 2.5 cm and 7.0 cm). The b values of these three fish species ranged from 2.974 to 3.075. The high r² values (all > .980) indicate that these relationships will be appropriate for use in fisheries management of these species.