HARBOR PORPOISE (PHOCOENA PHOCOENA) ABUNDANCE IN ALASKA: BRISTOL BAY TO SOUTHEAST ALASKA, 1991-1993

Between 1991 and 1993, Alaska harbor porpoise ( Phocoena phocoena ) abundance was investigated during aerial surveys throughout much of the coastal and offshore waters from Bristol Bay in the eastern Bering Sea to Dixon Entrance in Southeast Alaska. Line-transect methodology was used, and only those observations made during optimal conditions were analyzed. Survey data indicated densities of 4.48 groups/100 km², or approximately 3,531 harbor porpoises (95% C. I. 2,206-5,651) in Bristol Bay and 0.54 groups/100 km², or 136 harbor porpoises (95% C. I. 11-1,645) for Cook Inlet. Efforts off Kodiak Island resulted in densities of 1.85 groups/100 km², or an abundance estimate of 740 (95% C. I. 259-2,115). Surveys off the south side of the Alaska Peninsula found densities of 2.03 groups/100 km² and an abundance estimate of 551 (95% C. I. 423-719). Surveys of offshore waters from Prince William Sound to Dixon Entrance yielded densities of 4.02 groups/100 km² and an abundance estimate of 3,982 (95% C. I. 2,567-6,177). Combining all years and areas yielded an uncorrected density estimate of 3.82 porpoises per 100 km², resulting in an abundance estimate of 8,940 porpoises (CV = 13.8%) with a 95% confidence interval of 6,746-11,848. Using correction factors from other studies to adjust for animals missed by observers, the total number of Alaska harbor porpoises is probably three times this number.     

“Porpicide” in California: Killing of harbor porpoises (Phocoena phocoena) by coastal bottlenose dolphins (Tursiops truncatus)

Between 2007 and 2009, we witnessed three aggressive interactions between harbor porpoises and bottlenose dolphins in Monterey Bay, California. This is the first time such aggression has been documented in the Pacific, and the first time a harbor porpoise was collected immediately after witnessing its death, inflicted by bottlenose dolphins. Of the bottlenose dolphins present, 92% were males either confirmed (61%) or putative (31%). Since 2005, 44 harbor porpoise deaths inflicted by bottlenose dolphins were documented in California. Aberrant behavior was rejected as a cause of aggression, based on widespread documentation of similar behaviors in other populations of free‐ranging bottlenose dolphins. The evidence for interspecies territoriality as a form of competition for prey was weak: there is little dietary overlap and there are differences in bottlenose dolphin and harbor porpoise distribution patterns in California. Object‐oriented play was plausible as a form of practice to maintain intraspecific infanticidal skills or a form of play to maintain fighting skills between male associates. Contributing factors could be high‐testosterone levels, as attacks occurred at the height of the breeding season, and/or a skewed operational sex ratio. Ultimately, we need more information about bottlenose dolphin social structure at the time of the aggression.     

ULTRASTRUCTURAL AND BIOCHEMICAL COMPARISONS OF DENDRODENDRITIC SYNAPTOSOMES FROM BOVINE SUPERIOR COLLICULI AND OLFACTORY BULBS WITH AXODENDRITIC AND AXOSOMATIC SYNAPTOSOMES

Abstract– The buoyant density, ultrastructure and protein composition of dendrodendritic (DD), axodendritic (AD) and axosomatic (AS) synaptosomes were compared. DD synaptosomes prepared from either bovine superior colliculi or olfactory bulbs sedimented in 0.32 m -sucrose at 1000 g whereas AD and AS synaptosomes from frontal and temporal lobe cortices sedimented at 10.000 g . In gradients of Renografin the DD contacts banded at a density of 1.12 whereas AD and AS banded at 1.07. The DD contacts appeared as large clusters of serial contacts, and each individual terminal had a mean surface area of 1.48 μm²; the mean area of AD and AS terminals was less than 0.35 μm². The protein compositions of DD, AD and AS synaptosomes were quite similar, with minor exceptions. These findings suggest that different synaptosmal types evolved from common membrane constituents.     

AXIAL MUSCULATURE IN THE DOLPHIN (TURSIOPS TRUNCATUS): SOME ARCHITECTURAL AND HISTOCHEMICAL CHARACTERISTICS

In view of the supposition that a dolphin can swim faster than would be predicted based on its physical features and presumed muscle power potential, studies were initiated to reevaluate the assumptions made in reaching these conclusions. Several previous studies have shown that the architectural and histochemical properties of a skeletal muscle dictate its force, velocity and displacement properties. This study examined the muscle fiber lengths and tendon arrangements of the dorsal and ventral axial muscles in dolphins ( Tursiops truncatus ). Fiber type and fiber size distributions were determined to reflect the general biochemical characteristics of the musculature. The dorsal muscles had a higher mean fiber length (167 Vs. 90 mm) and the range within and across different dorsal muscles was less (141–199 vs. 37–185 mm) than in the ventral muscles. Both the dorsal and ventral muscles consisted of an overall mean of 50 percent slow twitch and 50 percent fast twitch fiber types. The fast twitch fibers were 67 percent larger (2,200 vs. 1,317 μ m ²) than the slow twitch fibers in the ventral and 38 percent larger (1,213 Vs. 879 μm²) in the dorsal muscles. In addition, the mean cross sectional area of the fibers in the ventral muscles was approximately 65 percent greater (1,750 vs. 1,072 μm²) than those in the dorsal muscles. The shorter, larger-diameter fibers of the ventral musculature give it a greater potential for force production for a given amount of muscle mass. In contrast, the dorsal muscles appear to be designed to optimize velocity and displacement, ( i.e. , longer fibers). These findings contribute to the information necessary for the determination of the power potential of the musculature of the dolphin.     

Fish production in Oued Sebaou, a seasonal river in North Algeria

Fish were sampled by electrofishing at three contiguous sites 26 km from the source of Oued Sebaou, a seasonal river in North Algeria. River discharge ranges from 300 m³s⁻¹ in the peak of the rainy season to 0.1 m³s⁻¹ at the end of the dry season. Extensive gravel extraction from the river bed takes place during the dry season.
Two species were recorded at each site: Barbus callensis , which is heavily fished locally, and Anguilla anguilla . The three sample maximum likelihood Zippin method was used to estimate mean density and standing crops, which were: barbel, 452 fish ha⁻¹, 5.33 kg ha⁻¹; eels, 149 fish ha⁻¹, 3.04 kg ha⁻¹. Estimated average biomass and production were: barbel, 2.31 kg ha⁻¹, 4.27 kg ha⁻¹ year⁻¹; eels, 1.51 kg ha⁻¹, 2.60 kg ha⁻¹ year⁻¹.     

Short-term thermal acclimation induces adaptive changes in the inner mitochondrial membranes of fish skeletal muscle

In the oxidative muscles (musculi laterales superficiales) of crucian carp Carassius carassius acclimated for 6 weeks to either 5 or 25° C, the volume density and the surface density of fibres per tissue did not differ significantly between the control and experimental groups. The correlation ratio (μ²) for these values was below 50, 39·3 and 43·9 respectively. After acclimation to 5° C, the surface density of outer mitochondrial membrane per fibre increased significantly from 0·93 to 1·23m² cm⁻³ in the summer population but dropped from 0·94 to 0·67 m² cm⁻³ in the winter population. The surface density of outer mitochondrial membrane per mitochondrion increased from 3·24 to 4·52 m² cm⁻³ in summer fish. After acclimation to 25° C, the surface density of inner mitochondrial membranes per muscle fibre decreased from 4·04 to 1·79 m² cm⁻³ in summer fish and from 3·86 to 1·07 m² cm⁻³ in winter fish. The surface density of inner mitochondrial membranes per mitochondrion increased from 14·17 to 15·60 m²cm⁻³ in summer fish but dropped from 13·91 to 10·67 m² cm⁻³ in winter fish. Correlation matrices demonstrate a negative correlation of the surface density of outer mitochondrial membrane per mitochondrion with the volume density of mitochondria per fibre and temperature, suggesting cold-induced proliferation of small mitochondria. It was concluded that short-term cold acclimation increased surface area of the inner mitochondrial membranes in summer fish.     

Buoyancy regulation and aggregate formation in Amoebobacter purpureus from Mahoney Lake

Abstract The meromictic Mahoney Lake (British Columbia, Canada) contains an extremely dense layer of purple sulfur bacteria ( Amoebobacter purpureus ). The buoyant density of Amoebobacter cells grown in pure culture at saturating light intensity was significantly higher (1027–1034 kg m⁻³) than the density of lake water (1015 kg m⁻³). When stationary cultures were shifted to the dark, the gas-vesicle content increased by a factor of 9 and buoyant density decreased to 1002 kg m⁻³ within three days.
A novel mechanism of cell aggregation was detected for the Mahoney Lake strain. Dense cell aggregates were formed after depletion of sulfide. Formation of aggregates was correlated with an increase in cell surface hydrophobicity. Cell aggregates could be disintegrated within less than 1 s by addition of sulfide or various thiol compounds. Mercaptanes with a branched structure in the vicinity of the terminal thiol group, compounds with esterified thiol groups (methylmercaptanes), reducing compounds lacking thiol groups and detergents did not influence aggregate stability. Cell aggregates disintegrated upon addition of urea or of proteinase K. Addition of various sugars had no effect on aggregation; this points to the absence of lectins. The results indicate that cell-to-cell adhesion in A, purpureus ML1 is mainly caused by a hydrophobic effect and includes a specific mechanism possibly mediated by a surface protein.
Extrapolation of laboratory results to field conditions demonstrated that both regulation of buoyant density and formation of cell aggregates result in passive accumulation of cells at the chemocline and contribute to the narrow stratification of A. purpureus in Mahoney Lake.     

Bouyancy regulation and aggregate formation in Amoebobacter purpureus from Mahoney Lake

Abstract The meromictic Mahoney Lake (British Columbia, Canada) contains an extremely dense layer of purple sulfur bacteria ( Amoebobacter purpureus ). The buoyant density of Amoebobacter cells grown in pure culture at saturating light intensity was significantly higher (1027–1034 kg m⁻³) than the density of lake water (1015 kg m⁻³). When stationary cultures were shifted to the dark, the gas-vesicle content increased by a factor of 9 and buoyant density decreased to 1002 kg m⁻³ within three days.
A novel mechanism of cell aggregation was detected for the Mahoney Lake strain. Dense cell aggregates were formed after depletion of sulfide. Formation of aggregates was correlated with an increase in cell surface hydrophobicity. Cell aggregates could be disintegrated within less than 1 s by addition of sulfied or various thiol compounds. Mercaptanes with a branched structure in the vicinity of the terminal thiol group, compounds with esterified thiol groups (methyl-mercaptanes), reducing compounds lacking thiol groups and detergents did not influence aggregate stability. Cell aggregates disintegrated upon addition of urea or of proteinase K. Addition of various sugars had no effect on aggregation; this points to the absence of lectins. The results indicate that cell-to-cell adhesion in A. purpureus ML1 is mainly caused by a hydrophobic effect and includes a specific mechanism possibly mediated by a surface protein.
Extrapolation of laboratory results to field conditions demonstrated that both regulation of buoyant density and formation of cell aggregates result in passive accumulation of cells at the chemocline and contribute to the narrow stratification of A. purpureus in Mahoney Lake.     

Effect of decreased environmental salinity on growth hormone cells in the gilthead sea bream (Sparus aurata)

The effect of decreased environmental salinity on growth hormone producing cells (GH cells) of the adenohypophysial proximal pars distalis has been studied in the gilthead sea bream ( Sparus aurata L.) adapted to sea water (SW, 980 mosmol kg ⁻¹) and brackish water (BW, 200 mosmol kg ⁻¹). A combined immunocytochemical, morphometric and electron microscopic study was carried out. GH cells offish adapted to BW occupied a greater hypophysial volume (about 21% of the total hypophysial volume in BW, 17% in SW) and had a larger nuclear area (mean 16 μm² in BW, 13 μm² in SW) than GH cells of SW-adapted fish. The immunoreactivity against a salmon GH-antiserum was lower in BW (mean optical density 142 in BW, 159 in SW). Ultrastructural characteristics of GH cells of BW-adapted fish were distended rough endo-plasmatic reticulum and large secretory granules (about 216 nm in diameter for BW, 209 nm in SW). Volumetric, densitometric and ultrastructural evidence suggested that the synthesis and release of GH were activated in S. aurata adapted to hypo-osmotic environment.     

Toxicity of six commercially formulated insecticides and biopesticides to third instar larvae of mushroom sciarid, Lycoriella ingenua Dufour (Diptera: Sciaridae), in New South Wales, Australia

Abstract  Lycoriella ingenua is one of the major pests of cultivated mushrooms, Agaricus bisporus (Lange) Imbach . Insecticide resistance among mushroom sciarid populations has been reported from other countries, and there is a need to determine the toxicity of currently approved and potential pesticides to sustain control of mushroom sciarid populations in Australia. The present study investigated the toxicity of six commercial formulations of insecticides or biopesticides against third instar larvae of L .  ingenua using laboratory bioassays. Insecticide treatments were incorporated into the growing medium for sciarid larvae and the concentration of the pesticide, which killed 90% of the test population (LD₉₀) determined the efficacy of selected insecticides. Triflumuron was the most effective insecticide against L. ingenua with an LD₉₀ of 53.12 mg active ingredient (a.i.)/m² followed by cyromazine (LD₉₀, 179.68 mg a.i./m²) and diazinon (LD₉₀, 261.72 mg a.i./m²). Abamectin and Bacillus thuringiensis ssp. israelensis were ineffective against L. ingenua . Steinernema feltiae , an entomopathogenic nematode, reduced the number of third instar larvae of L. ingenua only when applied at a higher rate (LD₉₀, 732 422 nematodes/m²) than was recommended on the label.     

SOCIAL ECOLOGY OF BOTTLENOSE DOLPHINS IN THE KVARNERIĆ (NORTHERN ADRIATIC SEA)

A bottlenose dolphin community was studied from small inflatable craft from 1987 to 1994 in a relatively large area (about 800 km²) east of the islands of Loˇsinj and Cres, northern Adriatic Sea. A total of 106 individuals were photoidentified based on natural permanent marks on their dorsal fins. Most of the dolphins were resighted on a regular basis, indicating a high level of year-round site fidelity, although their range was evidently greater than the chosen study area. Dolphin density was highly variable and considerably lower than for most well-known bottlenose dolphin communities. Groups averaged seven individuals, with a mode of two. Groups entirely composed of adults were the smallest, groups with calves the largest. Group fluidity was high, seasonal and yearly changes in mean group size being also considerable. Summer was the peak calving season, with a striking variation in the number of births on alternate years. Poor evidence of shark predation was found. The social organization of this dolphin community seemed to be highly flexible, possibly as an adaptation to cope with environmental changes as well as with a limited and variable availability of prey.     

The population dynamics of young trout (Salmo trutta L.) in a Danish brook

The population size, dispersal of fry, growth of fry in relation to density, mortality and production of young trout ( Salmo trutta L.) were studied in a Danish brook during 1970–1972. In the first few months after emergence downstream emigration of fry took place both in 1971 and 1972, after which the trout became stationary. Growth was inversely density dependent and mortality was density dependent in the months just after emergence. Later mortality was constant and independent of density. Trout production varied between 10 g/m² and 18.6 g/m² in the 2 years.     

Diel abundance, migration and feeding of fish larvae (Eleotridae) in a floodplain billabong

Eleotrid larvae (2.1–16 mm) were collected from surface waters of a billabong in south-eastern Australia. Estimates of larval density in plankton net samples at night averaged 148.3 larvae per m³ and 16.6 larvae per m³ during the day. In contrast, pump samples provided density estimates of 8.3 larvae per m³ at night and 0.9 larvae per m³ during the day. Larval densities did not differ between open water, snag (fallen tree) and Typha habitats, but Typha habitats yielded larger larvae than other habitats. 32.9% of larvae in pump samples were damaged and unmeasurable, creating a bias favouring larger larvae. The modal length of larvae in net samples at night was 5–6 mm, compared with 3–4 mm during the day, reflecting both greater net avoidance by larger larvae during the daytime and dispersal of smaller larvae from the surface at night. Dispersion patterns of larvae suggest that classes of larvae smaller than, and larger than 5.0 mm exhibit reciprocal diel vertical migration behaviour linked to ontogenetic changes in diet. Larvae less than 5 mm fed only during the day and preyed exclusively on rotifers, whereas larger larvae continued to feed at night and consumed mostly planktonic crustaceans.     

Floristic composition, structure, and dynamics of an upper montane rain forest in Southern Ecuador

Two 1 ha plots of undisturbed upper montane rain forest in southern Ecuador were sampled for all trees with a dbh ≥ 5 cm. An extraordinarily high α-diversity for a forest near treeline is described. The "non-ridge forest" plot at 2900 m elevation has 75 species and 28 families ha^-1 and is believed to represent an advanced stage of succession whereas, the "ridge forest" plot at 2700 m elevation with 90 species and 38 families ha^-1 has a more rapid turn-over rate probably due to a more unstable environment. Downslope forces (soil creep) are discussed as a possible cause for 32–44% of all trees being inclined more than 30° in the moderately steep terrain (average slope 20° in both study plots). The plot of "non-ridge forest" is characterized by a much greater biomass whether expressed as basal area (44 m² versus 15 m²) or stem volume (214 m³ versus 52 m³), while the density is equally high (2310 versus 2090 trees ha^-1) in both plots. Families with Family Importance Value >25 / ha^-1 are Clusiaceae, Cunoniaceae, Melastomataceae, Myrsinaceae, and Ternstroemiaceae.     

The standard metabolic rate of dolphin fish

The standard metabolic rates (SMRs) of 11 (1.395–4.125 kg) dolphin fish (mahimahi or dorado, Coryphaena hippurus ) were measured at 25°± 0.5°C. Fish were prevented from swimming with neuromuscular blocking agents and force ventilated. Heart rates were determined simultaneously. SMRs (358–726 mg O₂ h ^–1) were several times those of other similarly sized active teleosts such as salmonids, but close to those of tunas. Heart rates (84–161 beats min ^–1) were also high, but alike those of tunas under similar circumstances. As in tunas, the high SMR of dolphin fish may result from high osmoregulatory costs engendered by their large gill surface areas and/or other adaptations necessary for achieving exceptionally high maximum metabolic rates.     

Effects of light and temperature on the cell size and some biochemical components in two freshwater cryptophytes

The effects of light and temperature on cell size and cellular composition (chlorophyll, protein, carbohydrate) of two freshwater cryptophytes were studied with batch cultures. Neither of the species had a constant cell size but the size varied with growth conditions. At each temperature the smallest cells were recorded at the lowest experimental photon flux density. The smallest cells of Cryptomonas 979/67 had an average volume of 232 μm³ and the largest ones 1 020 μm³. In Cryptomonas 979/62 the smallest and largest cells measured 4 306 μm³ and 12 450 μm³. Both species increased their cellular chlorophyll content when PFB dropped below 110–120 μmol m^-2 s^-1. The highest and lowest chlorophyll contents of 979/67 were 7.45 fg μm^-3 and 0.55 fg μm^-2 respectively. For 979/62 the corresponding values were 10.23 fg μm^-3 and 0.93 fg μm^-3. In both species the protein content remained stable at PFDs higher than 110–120 μmol m^-2 S^-1. The highest content of protein measured in 979/67 was 638 fg μm^-3 and the lowest 147 fg μm^-3. For 979/62 these values were 1 036 fg μm^-3 and 148 fg μm^-3 respectively. The carbohydrate results were less clear and no pattern either in response to photon flux density or temperature was obvious. The lowest and highest contents recorded for 979/67 were 62 fg μm^-3 and 409 fg μ^-3 and for 979162, 36 fg μm^-3 and 329 fg μm^-3     

Comparison of lipids in selected tissues of the Florida manatee (Order Sirenia) and bottlenose dolphin (Order Cetacea; Suborder Odontoceti)

The position, porosity and oil-filled nature of the zygomatic process of the squamosal bone (ZPSB) of the Florida manatee, Trichechus manatus latirostris, suggest that it may have a similar sound conduction function to that of the intramandibular fat body (IMFB) of the bottlenose dolphin, Tursiops truncatus, and other odontocetes. To examine this possibility we determined the lipid composition of the ZPSB and adipose tissue from the dorsal part of the head region of the Florida manatee, and compared it to that of the dolphin IMFB and melon (another fatty area implicated in sound conduction in odontocetes). Lipids from manatee ZPSB and from adipose tissue were composed almost entirely of triacylglycerols. The most abundant fatty acids of the ZPSB were 18:1, 16:0, 14:0 and 16:1. The major fatty acids of the adipose tissue in the head were the four mentioned above, along with 12:0 and 18:0. Manatee samples did not contain isovaleric acid (iso-5:0), which was found in the bottlenose dolphin IMFB and melon, and has been related to sound conduction in dolphins and some other odontocetes. Thus, if manatee tissues are capable of sound conduction, and this process does occur through the ZPSB, a somewhat different suite of lipid components must support this function.     

Biological Control of Anopheles sinensis with Native Fish Predators (Aplocheilus and Aphyocypris) and Herbivorous Fish, Tilapia in Natural Rice Fields in Korea

ABSTRACT A confined field experiment was conducted to investigate biological control of malaria and inland filariasis vector, Anopheles sinensis Wied. by combined use of larvivorous fishes, Aplocheilus latipes or Aphyocypris chinensis and herbivorous, Tilapia mossambicus niloticus in natural rice fields at Banwol near Suwon, Gyeonggi province from June through October, 1989. In the presence of naturally breeding Aplocheilus at the density of 0.8 fish/m² water surface, the natural control of Anopheles larvae ranged 34.4% to 51.6% from June through August; later supplemental introduction of herbivore (Tilapia) at the release rate of 1-pair per 10 m² resulted in 67.8% increased to 80.0% control of Anopheles sinensis in 3rd and 5th week respectively. In a combined fish release at the rate of 1.0 fish/m² of Aphyocypris and 1-pair/10 m² of Tilapia produced 67.3% and 82.1% mosquito larval reduction in 3rd and 5th week periods, respectively. The similar pattern of gradual but significant suppression of mosquitoes was also evident in separate rice paddy in 4-5 week period, maintaining ca. 75'82% for the subsequent mosquito breeding season in comparison with control plot.     

Mechanics of locomotion and jumping in the forelimb of the horse (Equus): in vivo stress developed in the radius and metacarpus

Principal stresses acting in the midshafts of the radius and metacarpus of the horse were determined from in vivo strain recordings during locomotion and jumping. Ground forces and limb position were also recorded. Over a range of speed and gait the radius was subjected to considerable bending, whereas the metacarpus was loaded primarily in axial compression. As a result, peak stresses acting in the radius (maximum: –45 MN/m²) were consistently 50% greater than those acting in the metacarpus (maximum: –31 MN/m²). The increase in peak bone stress (radius: 119% and metacarpus; 114%) with increasing speed was matched by a 103% increase in the mass-specific vertical force ( A _v) exerted on the limb and a 55% decline in duty factor of the limb. The forelimb was closely aligned with the direction of ground force during the support phase (<9° when peak force acted) to minimize bending forces exerted on the distal limb bones. Hence, bending of the radius resulted mainly from axial forces acting about its longitudinal curvature. This was in contrast to the metacarpus, which is a much straighter bone.
Significantly greater stresses were recorded in each bone during jumping: –81 MN/m² in the radius and –53 MN/m² in the metacarpus. While the distribution of loading in the radius was similar to that during steady state locomotion, greater variability in the magnitude and/or distribution of metacarpal loading was observed between animals, largely due to differences in the orientation of the limb during takeoff and landing. These data demonstrate that the horse, despite its large size, maintains a safety factor of nearly 3–4 during peak performance.     

Mechanism of calcium-dependent salt tolerance in cells of Nitellopsis obtusa: role of intracellular adenine nucleotides

Abstract. The tonoplasts of internodal cells of Nitellopsis were removed by perfusing the vacuoles with media containing a Ca² chelator, EGTA. Treatment of tonoplast-free cells with 100 mol m³ NaCl induces a large membrane depolarization, a drastic decrease in the membrane resistance and an increase in Na⁺ influx. These events are identical to those that occur in intact cells subjected to high NaCl. These responses to NaCl are prevented if 10 mol m³ Ca²⁺ is supplied together with 100 mol m³ NaCl. The protective effect of Ca²⁺ is evident only when the intracellular ATP concentration exceeds 0.1 mol m³ and does not occur full when the intracellular ATP is removed. AMP at concentrations greater than 0.5 mol m³ or 0.25 mol m³ AMPPNP can replace ATP. It is concluded that ATP does not act as an energy source nor as a substrate for protein phosphorylation. ATP seems to exert its effects as a coeffector with Ca²⁺ in regulating the Na⁺ permeability of the plasma membrane.