Swimming Speed and Metabolic Rate during Routine Swimming and Simulated Diel Vertical Migration of Sergestes similis in the Laboratory
David L. Cowles
Abstract: Sergestes similis (Hansen, 1903) is a common mesopelagic vertically migrating shrimp common in the temperate and subarctic North Pacific Ocean. The species is a diel vertical migrator, although it remains primarily above the oxygen minimum layer in regions such as off California where the layer is well developed. This shipboard study with a computer-controlled swim tunnel provided the first continuous examination of this species’ swimming behavior and metabolism over a 24-hr cycle. Sergestes similis swam at a routine speed of around 4.4 to 4.95 cm sec-1. Burst speeds ranged from 14 to >20 cm sec-1. Swimming speeds during the day, at low temperatures simulating those at daytime depths, were similar to those at night at the higher temperatures characteristic of the surface. Night metabolic rates were higher than in the day, especially during the early night when most feeding activity may take place. Swimming speeds during times of simulated vertical migration averaged slightly faster than those of routine day or night swimming, averaging 6.2 cm sec-1 during the time of upward migration and 5.4 cm sec-1 during simulated downward migration, but the difference was not significant. Downward migration is not accomplished by passive sinking. Calculations based on observed swimming activities and metabolic rates indicate that vertical migration confers a clear metabolic energy savings to S. similis over remaining resident in surface waters, though this result may not be applicable to other vertical migrators and is likely moderated by decreased feeding opportunities at depth.
Review of the Fishes of the Genus Kuhlia (Perciformes: Kuhliidae) of the Central Pacific
John E. Randall and Helen A. Randall
Abstract: Ten species of fishes of the genus Kuhlia are recognized from Palau to Hawai`i in the North Pacific and from Fiji to Easter Island in the South Pacific: K. malo (Valenciennes) from fresh water in the Society Islands; K. marginata (Cuvier) from fresh water in the western Pacific, east to Kosrae, Caroline Islands, and Fiji; K. mugil (Forster) (K. taeniura is a synonym) from most of the Indo-Pacific (not the Hawaiian Islands) and the tropical eastern Pacific; K. munda (De Vis) from fresh and brackish water in Fiji, Vanuatu, New Caledonia, and Queensland (K. proxima Kendall & Goldsborough and K. bilunulata Herre are synonyms); K. nutabunda Kendall & Radcliffe from Easter Island; K. petiti Schultz from the Phoenix Islands, Malden Island, and the Marquesas Islands (Dules taeniurus marquesensis Fowler is a synonym); K. sandvicensis (Steindachner) from the Hawaiian Islands and other islands of the central Pacific; K. rupestris (Lacépède) from fresh water from East Africa to Samoa (K. caerulescens Regan from the Solomon Islands is a new synonym); K. salelea Schultz from fresh water in the Samoa Islands; and K. xenura (Jordan & Gilbert) from the Hawaiian Islands, with a mistaken type locality of El Salvador, Central America. The name K. sandvicensis has long been used for the common endemic species in the Hawaiian Islands; however, the original description leaves little doubt that it should apply to the species widely distributed in the central Pacific and only recently discovered in Hawai`i; it has usually been misidentified as K. marginata. The endemic Hawaiian species therefore takes the only available name, K. xenura (Jordan & Gilbert). Kuhlia sandvicensis differs from K. xenura in having a smaller eye (3.0-3.45 in head length, compared with 2.55-2.95 for K. xenura), straight dorsal profile of the head of adults (concave in xenura); usually 14 pectoral-fin rays (usually 15 in xenura), usually 50 lateral-line scales (usually 49 in xenura), gill rakers 38-43 (35-39 for xenura), and a dark reticular pattern dorsally on the head in life.
Decapod Crustaceans of the Headwater Streams of Pohnpei, Eastern Caroline Islands, Federated States of Micronesia
Donald W. Buden, D. Brian Lynch, John W. Short, and Trina Leberer
Abstract: Two species of Macrobrachium (Palaemonidae) and three atyid shrimp (Atyidae) species were identified among 986 decapod crustaceans collected in headwater streams on Pohnpei, Micronesia, during 1999 and among incidental collections in 2000. None is endemic to the island; all are indigenous or at least not of recent human introduction, and all occur widely in the Indo-West Pacific region and have a diadromous life history pattern. Both Macrobrachium lar (Fabricius, 1798) and M. latimanus (Von Martens, 1868) are common in Pohnpei rivers, but M. latimanus outnumbers M. lar especially in the uppermost reaches. Atyoida pilipes (Newport, 1847) accounted for 72% of the atyid sample, and it was the only decapod recorded at elevations as high as 604 m; Caridina weberi (De Man, 1892) composed 21% of the sample and C. typus (H. Milne Edwards, 1837) 6.4%. Ovigerous females were collected throughout the year for three of the five species; the absence of ovigerous Macrobrachium lar and Caridina typus during August-November was possibly due to small sample sizes. Freshwater shrimps do not currently form an important part of the diet of Pohnpei islanders, but historical accounts suggest that shrimps were utilized more in the past when imported foods and advanced technology for harvesting marine resources were not readily available.
Rediscovery of Talehsapia annandalei (Polychaeta: Pilargidae) in Songkhla Lagoon, Thailand
Sergio I. Salazar-Vallejo, Eijiroh Nishi, and Saowapa Anguspanich
Abstract: The pilargid polychaete Talehsapia annandalei Fauvel, 1932, has been rediscovered in its type locality and its taxonomic affinities are clarified. The genus is set off from remaining synelmins based on possession of palps completely fused and absence of tentacular cirri. The “jawlike” structure is rather a symmetrical, discontinuous pair of denticulated bands and is not a true jaw.
Links between the Southern Oscillation Index and Hydrological Hazards on a Tropical Pacific Island
James P. Terry, Rishi Raj, and Ray A. Kostaschuk
Abstract: River floods and hydrological droughts (low stream water resources) are a recurrent problem in different parts of Fiji, causing disruption and hardship for many rural communities. These extremes in fluvial behavior are associated with large seasonal variability in rainfall, generated by intense tropical storms in the wet season and prolonged rain failure in the dry season. Such conditions are linked to the influence of El Niño/Southern Oscillation (ENSO) in the Southwest Pacific. The Southern Oscillation Index (SOI) is the climatic measure of the strength of ENSO activities and shows good correspondence with (1) tropical cyclone flood magnitude and (2) critically low stream discharges after a 2-month time lag, in two of Fiji’s main river systems. If ENSO conditions become more frequent or sustained in the future as some climate models suggest, then the SOI will be a useful tool for projecting in advance the severity of hydrological hazards, which can assist in disaster mitigation and management.
Impacts of Feral Livestock on Island Watersheds
Dirk H. Van Vuren, Michael L. Johnson, and Lizabeth Bowen
Abstract: We assessed the effects of overgrazing by feral sheep on watersheds on Santa Cruz Island, California. Overgrazing had a marked effect on stream flow; flows were much greater in overgrazed than in lightly grazed watersheds early in the rainy season, but the difference vanished later in the season. This pattern can be explained by reduced infiltration and increased surface runoff of rainfall in overgrazed areas. Thus, feral livestock may affect island species not only directly by grazing and trampling, but also indirectly by altering hydrologic processes and therefore species that are dependent on these processes.
Black Coral: History of a Sustainable Fishery in Hawai`i
Richard W. Grigg
Abstract: The black coral fishery in Hawai`i has been sustainable for the past 40 yr. The fishery began in 1958, shortly after its discovery off Lahaina, Maui, by Jack Ackerman and Larry Windley, who later formed the company Maui Divers of Hawaii. Since that time, the black coral jewelry industry has gradually expanded and is valued in Hawai`i today at about $15 million at the retail level. In the 1970s, studies of the population dynamics of the major species established growth, recruitment, and mortality rates and led to the development of management guidelines including recommendations for a minimum size and maximum sustained yield. Results of a recent survey in 1998, reported in this paper, show that rates of recruitment and growth are near steady state and appear to account for the long-term stability of the fishery. However, recent technological advances and potential increases in demand could lead to increased rates of harvest. Should this happen, more stringent regulations may be required to avoid overexploitation of the resource.
Killer Whales (Orcinus orca) Sighted West of Ni`ihau, Hawai`i
Joseph R. Mobley Jr., Lori Mazzuca, Alison S. Craig, Michael W. Newcomer, and Scott S. Spitz
Abstract: A rare sighting of five killer whales (Orcinus orca), including one juvenile, occurred on 20 March 2000 during an aerial survey of waters west of the Hawaiian island of Ni`ihau. The sighting occurred ca. 11 km west of Kamalino Bay on Ni`ihau, at 21° 49′ N, 160° 20′ W. Killer whales are not unknown in Hawaiian waters, but the most recent confirmed sighting on record for Hawaiian waters was in 1979.
Vegetative Anatomy of the New Caledonian Endemic Amborella trichopoda: Relationships with the Illiciales and Implications for Vessel Origin
Sherwin Carlquist and Edward L. Schneider
Abstract: Light microscopy was used to study leaf hypodermis, vein sclerenchyma, stomatal subsidiary cell types, and root xylem in liquid-preserved material of Amborella trichopoda; oblique borders on tracheid pits, scalariform end walls on tracheids, and porosities in end-wall pit membranes were studied with scanning electron microscopy. Amborella shares stomatal configurations, nodal type (in part), ray types, and porose pit membranes in tracheary elements with Illiciales s.l., but differs from that order in lacking oil cells, vessels, and grouped axial parenchyma cells. These data are consistent with a basal position in angiosperms for Amborella, and for a close relationship with, but not inclusion in, Illiciales; inclusion in a monofamilial order is conceivable. Both loss of pit membranes or pit membrane portions on end walls and increase in cell diameter are requisites for origin of vessels. Sarcandra and Illiciaceae show these early stages in origin of vessels; Amborella shows development of porosities in pit membranes. Vessel presence or absence may not be strictly bipolar, because some primitive vessel elements exhibit at least some tracheidlike characteristics and are thus transitional, and because changes in at least two characters define vessel origin.
Pacific Science Assocation