Near real time satellite tracking of striped marlin (Kajikia audax) movements in the Pacific Ocean

High-resolution satellite locations were obtained from striped marlin using Argos transmitters attached to the upper lobe of the caudal fin. Twenty-six striped marlin were tagged off New Zealand (2005–2007) and tracked as far as the central Pacific Ocean. Caudal fin mounted Argos tags generated 1,524 locations during a total of 659 tracking days [mean 25 (±21.24) days per fish and 2.3 (±2.30) locations per day]. 38% of locations have an estimated accuracy of ±1 km or better. Displacement rates from high quality locations ranged from 2.9 to 170.8 km in a 24 h period, with a mode at 20–30 km and a mean of 45 km/day. The caudal fin attachment methodology and antenna configuration was adjusted each season to improve transmission life and data quality, with the best results obtained in the last year of deployments (2007). The longest track duration was 102 days, with a total displacement of 4,959 km and a total track distance from all locations received of 6,850 km. Tag shedding and antenna failure appear to have limited the duration of tracks from SPOT tags. The high temporal and spatial resolution data revealed behaviours not previously observed in striped marlin, including associations to subsurface bathymetric features. High resolution location data such as these are useful inputs for statistical models used to investigate habitat selection and switching between different behavioural modes. The geolocations calculated using ukfsst estimates from PAT tag data had RMS errors of 1.01° latitude and 0.59° longitude when compared with SPOT tag Argos locations.     

Latitudinal symbiont zonation in <Emphasis Type="Italic">Stylophora pistillata</Emphasis> from southeast Africa

Studies on latitudinal gradients in Symbiodinium diversity on scleractinian corals are largely restricted to warm-water low latitude locations, and it appears that there is a shift in symbiont distributions with increasing latitude. The Symbiodinium assemblages of high latitude coral communities have largely been undocumented despite occupying an important transitional zone between tropical and temperate regions. Using a combination of the internal transcribed spacer region 2 (ITS2) and denaturing gradient gel electrophoresis (DGGE), we assessed the cladal and subcladal variability of Symbiodinium in the widely distributed species Stylophora pistillata along a latitudinal transect in southeast African waters which extended into high latitude locations. All colonies examined belonged to clade C. Six unique ITS2-DGGE banding profiles (designated C_spa to C_spf) were observed, which showed a latitudinal distribution from north to south, most likely a result of a gradient in water temperature and irradiance driven by riverine input in the southern regions. Sequence analysis revealed that all sequences except one did not match previously identified clade C sub-types, probably due to the lack of regional information in the Western Indian Ocean when compared to the Caribbean and Pacific. This study further supports the applicability of ITS2-DGGE in studies on Symbiodinium diversity, and highlights that potentially ecologically informative biogeographic patterns may be overlooked when only cladal designations are employed.     

UV-radiation versus grazing pressure: long-term floating of kelp rafts (<Emphasis Type="Italic">Macrocystis pyrifera</Emphasis>) is facilitated by efficient photoacclimation but undermined by grazing losses

Large quantities of floating macroalgae are traveling in coastal waters of the SE Pacific and in other temperate climate zones. While afloat, these algae are potentially exposed to full solar radiation, including UVA and UVB, which can have profound effects on their physiological and growth performance. Latitudinal variations in UV-radiation (UVR) are hypothesized to affect floating algae differently with higher impacts at low latitudes than at high latitudes. In addition, UVR together with grazing might accelerate the demise of floating kelps. This hypothesis was tested with outdoor laboratory experiments in which sporophytes of the giant kelp Macrocystis pyrifera (L.) C. Agardh were exposed to a combination of different UVR regimes (PAR only, PAR + UV) and grazing at three sites along the Chilean coast (20°S, 30°S, and 40°S). A latitudinal trend in irradiance was detected with increasing values from 40°S to 20°S. Surprisingly, floating M. pyrifera responded with a high acclimation potential within this latitudinal UVR gradient. At 20°S, floating kelps were slightly sensitive to UVR, which was reflected in reduced blade growth. At 30°S, physiological responses were hardly affected by the prevailing irradiance but sporophyte growth and thus persistence mainly depended on the presence or absence of amphipod grazers. At high latitudes, grazing had only minor impacts on algal biomass and blade growth, and kelps thrived well under all tested environmental conditions. Overall, our results reveal that floating M. pyrifera was only slightly affected by UVR and that sporophytes can efficiently acclimate over a latitudinal UVR gradient that spans from 20°S to 40°S. Given this high acclimation potential, we suggest that these (and possibly other) positively buoyant algae are important dispersal agents over a wide range of temperate latitude conditions.     

Horizontal movement of ocean sunfish, <Emphasis Type="Italic">Mola mola</Emphasis>, in the northwest Atlantic

Data were retrieved from 25 ocean sunfish (Mola mola) that were tagged with pop-up satellite archival tags in the southern Gulf of Maine (n = 6), off Nantucket Island (n = 17), and off the coast of Georgia (n = 2) between September 2005 and March 2008. Tags remained attached from 7 to 242 days, with a mean attachment period of (X ± SD) 107.2 ± 80.6 days. Ocean sunfish tagged in the Gulf of Maine and southern New England left those areas in the late summer and early autumn and moved south along the continental shelf break. Fish traveled as far south as the Bahamas and the Gulf of Mexico. By moving south, sunfish experienced similar mean sea surface temperatures throughout the tagging period. The maximum straight-line distance traveled by a tagged Mola mola was 2,520 km in 130 days. Two tagged ocean sunfish entered the Gulf of Mexico, one in the December and one in July. Movements were associated with frontal features created by the Gulf Stream and fish moved farther offshore in 2007 when the Gulf Stream was deflected from the shelf break.     

Response to light by trochophore larvae of Spirobranchus giganteus

Trochophore larvae of Spirobranchus giganteus (Pallas) respond positively to white light at levels of illumination from 1 to 2 168×10¹⁴ quanta cm^-2 s^-1. In this range the strength of the response is not correlated with irradiance level. The response is increased by dark adaptation. At low levels of irradiance (0.1-2.0×10¹⁴ quanta cm^-2 s^-1) larvae respond positively to blue (360-510 nm, max. 430 nm) and green (475–620 nm, max. 530 nm) light but not to wavelengths of 590 nm or over. The light response develops gradually during the 12 h following the appearance of the eyespot and is maintained throughout the remainder of the planktonic phase.     

Comparison of light- and SST-based geolocation with satellite telemetry in free-ranging albatrosses

Light-based archival tags are increasingly being used on free-ranging marine vertebrates to study their movements using geolocation estimates. These methods use algorithms that incorporate threshold light techniques to determine longitude and latitude. More recently, researchers have begun using sea surface temperature (SST) to determine latitude in temperate regions. The accuracy and application of these algorithms have not been validated on free-ranging birds. Errors in both geolocation methods were quantified by double-tagging Laysan (Phoebastria immutabilis Rothschild) and black-footed (P. nigripes Audubon) albatrosses with both leg-mounted archival tags that measured SST and ambient light, and satellite transmitters. Laysan albatrosses were captured and released from breeding colonies on Tern Island, northwestern Hawaiian Islands (23°52N, 166°17W) and Guadalupe Island, Mexico (28°31N, 118°10W) and black-footed albatrosses from Tern Island. Studies were carried out between December 2002 and March 2003. For all birds combined, the mean ± SD great circle (GC) distance between light-based locations and satellite-derived locations was 400±298 km (n=131). Errors in geolocation positions were reduced to 202±171 km (n=154) when light-based longitude and SST-based latitude (i.e. SST/light) were used to establish locations. The SST/light method produced comparable results for two Laysan albatross populations that traveled within distinctly different oceanic regions (open ocean vs more coastal) whereas light-based methods produced greater errors in the coastal population. Archival tags deployed on black-footed albatrosses returned a significantly higher proportion of lower-quality locations, which was attributed to interference of the light sensor on the tag. Overall, the results demonstrate that combining measures of light-based longitude and SST-based latitude significantly reduces the error in location estimates for albatrosses and can provide valid latitude estimates during the equinoxes, when light-based latitude measurements are indeterminate.Communicated by J.P. Grassle, New Brunswick     

Emerson enhancement effect and quantum yield of photosynthesis for marine macroalgae in simulated underwater light fields

The contribution of enhancement to the total photosynthesis of marine macroalgae in their natural habitats was estimated by comparing the photosynthesis measured by O₂-electrode in five broad-band light fields with that predicted (on the assumption that no enhancement was occurring) from the photosynthetic action spectrum of each plant and the spectral distribution of the light fields. The excess of measured values divided by calculated values provided a measure of enhancement. Although 37% enhancement was observed for red algae in unfiltered quartz-iodine light, and 18% for green and brown algae, substantially lower values were obtained for all species in more natural light fields. In those typical of shallow coastal waters, phycoerythrin-rich red algae exhibited 15 to 20% enhancement, but little enhancement (<5%) was detected in other algae. In a green light field, representing deep coastal water, there was no significant enhancement in any species, and only green and brown algae showed any enhancement (ca 8%) in broad-band blue light, similar to that in deep oceanic waters. Quantum yields of 0.09 to 0.10 O₂ molecules per absorbed photon were recorded in most light fields for green and brown algae with thin thalli, but yields decreased in the blue light field and in species with thicker thalli. All red algae had quantum yields of about 0.08 O₂ molecules per absorbed photon, except in the blue light field, in which quantum yields were reduced by 70%.     

Winter migration of magellanic penguins (Spheniscus magellanicus) from the southernmost distributional range

A total of 22 magellanic penguins (Spheniscus magellanicus) from Isla Martillo in the Beagle Channel, Argentina, were successfully satellite tracked in 2004 (n = 7), 2005 (n = 7) and 2006 (n = 8) to monitor their winter migration after moult. Only one magellanic penguin migrated northwards into the Pacific Ocean, whereas all others remained in the Atlantic Ocean. In general, these birds left the island in an easterly direction, rounded Cabo San Diego, the southeasterly tip of South America, and continued northwards occupying inshore waters mostly less than 50 km from the coast, only occasionally venturing further offshore. By the end of the transmission period, birds were still travelling northwards and the most northerly positions were obtained from birds located in the area of Peninsula Valdés, Argentina, at a latitude of around 42°S, some 1,500 km from their breeding site on Isla Martillo. The mean maximum distance to the breeding site was, however, only 624 ± 460 km. The mean minimum distance covered during the study period was 1,440 ± 685 km, which corresponded to a mean distance of 23.2 ± 6.6 km covered per day. The northbound migration of the penguins could be separated into periods of rapid movement, interspersed with periods during which the birds remained for some time in particular coastal regions. Areas with a high density of daily penguin positions were observed in three distinct areas: at the northeastern coast of Tierra del Fuego, at the southern entrance of Golfo San Jorge and to the northeast of the Peninsula Valdez. The observed migration pattern is presumably driven by the formation and subsequent dispersal of areas of enhanced productivity as the season progressed. Our findings also suggest that magellanic penguins are increasingly threatened by human activities in coastal areas as penguins migrate northwards.     

Change in zooxanthellae and mucocyte tissue density as an adaptive response to environmental stress by the coral, <Emphasis Type="Italic">Montastraea annularis</Emphasis>

Results from controlled in situ experimentation conducted on the leeward reef tract of Curaçao, Netherlands Antilles, indicate that the coral Montastraea annularis exhibits a complex, yet consistent, cellular response to increasing sea surface temperature (SST) and decreasing irradiance. This was determined by simultaneously quantifying and tracking the tissue density of zooxanthellae and mucocytes using a novel technique that integrates the lectin histochemical stain wheat germ agglutinin (WGA) with high-resolution (200 nm) optical epifluorescence microscopy. Coral colonies growing at 6-m water depth (WD) and an irradiance of 100.2 ± 6.5 μmol m^?2 s^?1 were treated with a shading experiment for 11 days that reduced irradiance to 34.9 ± 6.6, 72.0 ± 7.0 and 90.1 ± 4.2 μmol m^?2 s^?1, respectively. While a significant decrease in the density of both zooxanthellae and mucocytes were observed at all shade levels, the largest reduction occurred between the natural non-shaded control (44,298 ± 3,242 zooxanthellae cm^?2; 4,853 ± 346 mucocytes cm^?2) and the highest shading level (13,982 ± 1,961 zooxanthallae cm^?2; 2,544 ± 372.9 mucocytes cm^?2). Colonies were also sampled during a seasonal increase in SST of 1.5°C, where the density of zooxanthellae was significantly lower (from 54,710 ± 1,755 to 34,322 ± 2,894 cells cm^?2) and the density of mucocytes was significantly higher (from 6,100 ± 304 to 29,658 ± 3,937 cells cm^?2). These observations of coral cellular response to environmental change provide evidence to support new hypotheses for coral survival and the complex role played by mucus in feeding, microbial associations and resilience to increasing SST.     

A comparative analysis of the photobiology of zooxanthellae and zoochlorellae symbiotic with the temperate clonal anemone Anthopleura elegantissima (Brandt)

The temperate anemone Anthopleura elegantissima hosts two phylogenetically different symbiotic microalgae, a dinoflagellate Symbiodinium (zooxanthellae, ZX) and a chlorophyte (zoochlorellae, ZC), throughout certain regions of its latitudinal range. Because of the broad intertidal and geographic range of this anemone, we examined the role of irradiance to ascertain which specific symbiotic parameters are affected and whether light intensity governs the observed distributions of natural populations of ZX and ZC. Irradiance appears to be a key factor in regulating both the photophysiology and metabolism of this alga-cnidarian association. Regardless of light intensity, algal densities remained stable for anemones harboring ZX or ZC, whereas the mitotic indices of ZX and ZC both varied directly with light intensity. The chlorophyll content of ZX remained fairly constant regardless of irradiance; in contrast, ZC chlorophyll content was inversely proportional to light intensity. Regardless of irradiance, the carotenoid content of both symbionts was constant; however, ZX carotenoid levels were higher than those of ZC. Net photosynthesis was directly related to light intensity for both algal symbionts and ZX photosynthetic rates were consistently higher than those of ZC. Similarly, the potential carbon contribution of ZX and ZC to animal respiration (CZAR) displayed a direct relationship with light intensity, peaking at 800 µmol·m^-2·s^-1, then subsequently declined. Lower ZX growth rates, coupled with higher photosynthetic rates and higher CZAR estimates, compared to ZC, suggest that the ZX should be the dominant symbiont as light intensity increases; this may explain the high densities of anemones in the field containing ZX where the levels of irradiance are naturally high. These results support the interpretation that irradiance is a significant environmental parameter that dictates the microhabitat and latitudinal distribution of the two symbiotic algal taxa. This is the second in a series of papers examining the physical parameters that influence the distribution of ZX- and ZC-bearing A. elegantissima.     

Geolocation of free-ranging fish on the European continental shelf as determined from environmental variables

Demersal fish cannot readily be tracked using satellite-based or light-based geolocation techniques. As an alternative, we describe the tidal location method, which uses tidal data recorded by electronic data storage tags (DSTs), to determine geoposition. Times of high water (H) and tidal ranges (R) recorded by DSTs moored at known locations, and from free-swimming tagged plaice, Pleuronectes platessa, were compared with a North Sea tidal database to identify all positions with matching values of H and R. Within the recording precision of the tag (ǂ.2 m, ᆞ min) and the predicted accuracy of the model generated tidal data (ǂ.15 m, ᆨ min), geolocations over much of the North Sea and eastern English Channel were predicted to be accurate to within 40 km, sometimes to within 10 km. Positional estimates of the moored tags were within 15.7Dž.5 km of the actual locations. Geolocations made from tagged plaice within 5 days of release and 5 days pre-recapture were within 35ᆬ km and 37ᆫ km of release and recapture positions respectively. Our results demonstrate the ability of this method to accurately describe the migrations of North Sea plaice throughout their geographical range with a level of accuracy unattainable using light-based geolocation. The method could equally be applied to any shelf-dwelling demersal fish that periodically rests on the sea-bed for the duration of a tidal cycle. In fisheries management, the method has clear potential application in defining the movements and migrations of other commercial species.     

Satellite tagging of blue sharks (Prionace glauca) and other pelagic sharks off eastern Australia: depth behaviour, temperature experience and movements

Satellite telemetry was used to study the movements and behaviour of ten blue sharks and one individual each of shortfin mako, thresher and bigeye thresher off eastern Australia. The tracks showed latitudinal movements of up to 1,900 km, but none of the sharks travelled away from the eastern Australian region. Tracking periods did not exceed 177 days. All species showed oscillatory dive behaviour between the surface layers to as deep as 560–1,000 m. Blue sharks spent 35–58% of their time in <50 m depths and 10–16% of their time in >300 m. Of these four species, the bigeye thresher spent the least time in the surface layers and the most time at >300 m depth. All four species showed clear diel behaviour generally occupying shallower depths at night than during the day. Blue sharks were mainly in 17.5–20.0°C water, while the thresher sharks showed a more bimodal temperature distribution.     

Energy content and fecundity of capelin (<Emphasis Type="Italic">Mallotus villosus</Emphasis>) along a 1,500-km latitudinal gradient

Capelin is a planktivorous key fish species in many subarctic ecosystems representing the link between lower trophic levels and apex predators. Little is known, however, of capelin in Greenland waters, but it has been suggested that size and growth increases due to difference in food availability and temperature conditions along a 1,500 km south–north gradient on the west coast. It is presently unknown how the qualitative state of capelin energy content is affected along this gradient. Based on 2007 and 2008 samples, we show that energy content increases with capelin length in both spawning and non-spawning fish and that it varies with latitude in spawning fish along West Greenland (60–71°N). Combining our results on energy content with information on capelin growth along the same latitudinal climate gradient demonstrates that less and lower-quality food is available to capelin predators in the south than in the north.     

Reproduction,growth and photosynthesis of gametophytes of Laminaria saccharina grown in blue and red light

The induction of reproductive activity by blue light in female gametophytes of the brown alga Lamnaria saccharina has been investigated and related to other effects of red and blue light on these plants. Although germination of zoo-spores is slightly delayed in red light, female gametophytes grow at similar rates in blue and red light of the same quantum irradiance up to an age of 8 to 10 days, when plants in blue light begin to form eggs. The percentage of plants forming eggs is proportional to the total quanta of blue wavelengths received up to a saturating value of about 400 μE·cm^-2; a 50% response is induced by 200 μE·cm^-2. The action spectrum for the induction of fertility has a main peak at 430 to 450 nm, with two subsidiary peaks in the blue and one in the near-ultraviolet light, but the action spectrum for photosynthesis is quite different, with peaks in the red, green and blue regions. These results indicate that egg formation in female gametophytes occurs as a specific morphogenetic response to blue light, which is independent of photosynthesis and growth, and trial experiments with male gametophytes of L. saccharina and gametophytes of other species of Laminariales indicate that these plants react similarly.     

Variation in vegetation cover and livestock mobility needs in Sahelian West Africa

A new approach was developed to evaluate the implications of the spatiotemporal variability of green vegetation for the dispersion of livestock that is required to access quality forage in semi-arid Africa. Maximum NDVI (Normalized Difference Vegetation Index) at 1 km² resolution was determined for concentric rings (0–31 km radii) around 227 individual sample locations within the study area for 14 dates (between 1 April to 1 November) annually over the 2000–2010 period. A sigmoidal curve was fitted to points within the maximum NDVI × distance radii space to determine the asymptote distance (AD) – the radius at which further dispersion from the sample location does not lead to significant gains in access to green forage. AD was found to: increase with latitude (or increasing aridity); decline as the rainy season proceeds; and show no trend over the 2000–2010 period. These results introduce much-needed empirical data to current debates surrounding the scales of governance to support livestock mobility.     

Potential latitudinal variation in egg size and number of a geographically widespread reef fish,revealed by common-environment experiments

Variation in maternal reproductive traits was examined in field and reared populations of a geographically widespread reef fish, Pomacentrus coelestis (Pomacentridae), drawn from three different latitudes in Japan. Size-specific clutch size and clutch weight of wild fish increased with increasing latitude. Conversely, latitudinal variation in egg size of wild fish was obscure in same-season comparisons, probably because of the temperature effect on egg size. Common-environment experiments conducted at three temperatures showed that egg size decreased with increasing temperature in all populations. In the experiments, egg size, clutch size and clutch weight differed among populations at all temperatures, showing clear latitudinal clines. Females from low latitude spawned larger eggs at every experimental temperature. Size-specific clutch size and weight were greater in females from high latitude. Thus, the northern fish had a larger reproductive output per spawning and a larger number of smaller eggs in a spawning. Such interpopualtion variation in this fish is likely to be partially genetically based, although environmental effects on the variation cannot be entirely ruled out. This study provides evidence of potential latitudinal variation in the egg size and number in a coastal fish, by common-environment experiments. The close correspondence between latitudes and these maternal reproductive traits may be a consequence of local adaptation.     

Depth distribution and temperature preferences of wahoo (Acanthocybium solandri) off Baja California Sur, Mexico

The depth distribution and temperature preferences of wahoo (Acanthocybium solandri) were quantified in the eastern North Pacific using archival tags. One hundred and eight data-loggers were deployed on wahoo (105?C165-cm fork length) from 2005 to 2008 at three locations off of the coast of Baja California Sur, Mexico (Alijos Rocks, 25°00??N/115°45??W; Magdalena Bay Ridge, 25°55??N/113°21??W; Hurricane Bank, 16°51??N/117°29??W). Twenty-five tagged individuals (23%) were recaptured within close proximity (<20?km) of their release sites. Collectively, depth and temperature data from 499?days revealed a predominant distribution within the upper mixed layer, with an average (±SD) depth of 18?±?4?m during the day and 17?±?6?m at night. Wahoo spent 99.2% of the daytime and 97.9% of night above the thermocline, and the greatest depth achieved by any fish was 253?m. Mean dive duration (3.8?±?2.9 vs. 2.3?±?0.8?min) and the vertical rate of movement (3.8?±?1.3 vs. 3.0?±?0.5?m?min^?1) were greater at night when compared to day. Ambient temperatures obtained from tag records ranged from 11.1 to 27.9°C, with an average of 25.0?±?1.1°C. These data identify the importance of the warm, upper mixed layer for the wahoo. High recapture rates proximal to the deployment sites suggest seasonal site fidelity and reveal the economic importance of this resource to both commercial and recreational fisheries of the region.     

Movements,behavior, and habitat utilization of yellowfin tuna (<Emphasis Type="Italic">Thunnus albacares</Emphasis>) in the northeastern Pacific Ocean,ascertained through archival tag data

Sixty-eight yellowfin tuna, Thunnus albacares, (60-135 cm fork length) were caught and released with implanted archival tags offshore off Baja California, Mexico, during October 2002 and October 2003. Thirty-six fish (53%) were recaptured and the data were downloaded from all 36 recovered tags. Time at liberty ranged from 9 to 1,161 days, and the data were analyzed for the 20 fish that were at liberty for 154 or more days. The accuracy in the position estimates, derived from light-level longitude data and sea-surface temperatures (SSTs) based latitude, is about 0.41° in longitude and 0.82° in latitude, in this region. The movement paths, derived from position estimates, for the 20 yellowfin indicated that 19 (95%) remained within 1,445 km of their release locations. The estimated mean velocity along movement paths was 77 km/day. The southern and northern seasonal movement paths observed for yellowfin off Baja California are influenced by the seasonal movements of the 18°C SST isotherm. Cyclical movements to and from suitable spawning habitat (≥24°C SST) was observed only for mature fish. For the 12 fish that demonstrated site fidelity, the mean 95 and 50% utilization distributions were 258,730 km² and 41,260 km², respectively. Evaluations of the timed depth records resulted in discrimination of four distinct behaviors. When exhibiting type-1 diving behavior (78.1% of all days at liberty) the fish remained at depths less than 50 m at night and did not dive to depths greater than about 100 m during the day. Type-2 diving behavior (21.2% of all days at liberty) was characterized by ten or more dives in excess of 150 m during the day. Type-2 diving behavior is apparently a foraging strategy for fish targeting prey organisms of the deep-scattering layer during the day, following nighttime foraging within the mixed layer on the same prey. Yellowfin tuna exhibited occasional deep-diving behavior, and some dives exceeded 1,000 m, where ambient temperatures were less than 5°C. Surface-oriented behavior, defined as the time fish remained at depths less than 10 m for more than 10 min, were evaluated. The mean number and duration of surface-oriented events per day for all fish was 14.3 and 28.5 min, respectively. Habitat utilization of yellowfin, presented as monthly composite horizontal and vertical distributions, indicates confined geographical distributions, apparently resulting from an affinity to an area of high prey availability. The vertical distributions indicate greater daytime depths in relation to a seasonally deeper mixed layer and a greater proportion of daytime at shallower depths in relation to a seasonally shallower mixed layer.     

Effect of light quality on photosynthesis of the reef coral Montipora verrucosa

Pieces of the reef coral Montipora verrucosa (Lam.), collected from Kaneohe Bay, Oahu, Hawaii in 1982, were grown in four low-light treatments (11% sunlight): blue, green, red and the full spectrum of photosynthetically active radiation (PAR); and at high-intensity full PAR (90% sunlight). These acclimated corals were then tested for photosynthetic ability in blue, green, red, and white light. The photosynthetic parameters that were measured were; ligh-saturated photosynthetic rate, the initial slope of the photosynthesis/irradiance curve, the light intensity where these two lines crossed, and dark respiration. While acclimation intensity had a pronounced effect, the results also showed that the color of the acclimation treatment influenced the photosynthetic responses of the corals. The color of the light used in the measurements of photosynthesis had much less effect on the photosynthetic responses of the corals.Contribution No. 729 of the Hawaii Institute of Marine Biology     

Nitrate/nitrite poisoning in dairy cattle associated with consumption of forages irrigated with municipally treated wastewater

Twenty-three cases of nitrate poisoning were diagnosed in a dairy herd due to consumption of green grass, mainly alfalfa, which was irrigated with a municipally treated wastewater. Five cows were found dead and seven fetuses were aborted. Methemoglobin (MtHb) in blood reached 41.6 ± 7.5%, while hemoglobin concentration was low: 6.9 gm dL^–1. Nitrite in plasma was 1.6 ± 0.4 mmol; the levels of nitrate in suspected grass and water were 1.48 × 10³ ppm and 1.7 × 10³ ppm, respectively. The clinical picture included difficulty in breathing, shivering and brown discoloration of the mucous membranes of the vulva, vagina, and conjunctiva. The postmortem findings included dark brown carcasses with dark, nonclotted blood in the dilated vessels. Cardiac hemorrhages, pulmonary and rumen congestion, edema and hyperemia of the mucous membranes of the abomasums and small intestine were noticed in all examined animals. The postmortem examination of aborted fetuses revealed severe ascites and hydrothorax. Affected animals responded well to the treatment with methylene blue. After one week of treatment MtHb and nitrite in plasma were significantly reduced to their minimal levels (10.5% and 0.5 mmol), respectively. One week later, green-feed and water had no evidence of nitrate. A definitive diagnosis was made based on the clinical picture, postmortem findings, high MtHb level in blood, quantitative nitrite analysis of plasma and nitrate analysis of suspected green-grass and response to methylene blue treatment.