Leuresthes Tenuis Research Articles

A new early life-stage toxicity test using the California grunion ( leuresthes tenuis) and results with chlorpyrifos

California grunion were continuously exposed as embryos and fry to technical chlorpyrifos in two toxicity tests conducted in the same exposure apparatus. The first test, a 35-day early life-stage (ELS) test, began with approximately 2.5-day-old embryos that were exposed in flow-through aquaria in darkness until hatching was stimulated on Day 9 of exposure. The second toxicity test, a fry test, began with newly hatched fry and lasted 26 days. Test water temperature ranged from 23 to 26°C and salinity from 24.5 to 34.0%.. Results of the two tests were similar, indicating that exposure of embryos added little to the overall toxicity of chlorpyrifos to grunions. Percentage hatch of embryos was unaffected by the chlorpyrifos concentrations tested. Fry survival was apparently reduced in nominal concentrations ⩾ 1.0 μg/liter in both tests, but significantly so in concentrations ⩾ 1.0 μg/liter in the ELS test and ⩾2.0 μg/liter in the fry test. When compared with carrier controls, mean fish weights were significantly reduced in nominal chlorpyrifos concentrations ⩾ 0.5 μg/liter in the ELS test and ⩾1.0 μg/liter in the fry exposure. Mean bioconcentration factors were 770× for fish that survived the ELS test and 190× for those that survived the fry test. Results demonstrate the practicality of conducting ELS tests for the first time with a marine fish from the Pacific coastal waters of the United States.

Comparative acute sensitivities of early life stages of atherinid fishes to chlorpyrifos and thiobencarb

Sensitivity, expressed as the 96-hr LC50 derived from acute lethality tests, was compared for four ages (day-of-hatch, 7-day, 14-day, and 28-day) of three atherinid fishes:Leuresthes tenais (California grunion),Menidia menidia (Atlantic silverside), andMenidia peninsulae (tidewater silverside). Responses of each age-species combination exposed to the organophosphate insecticide chlorpyrifos and the carbamate herbicide thiobencarb were compared in both static and flowing seawater toxicity tests. Chlorpyrifos was highly toxic to all atherinids (96-hr LC50's ranged from 0.4 to 6.7 μg/ L); toxicity of thiobencarb was approximately two orders of magnitude lower (LC50 values from 199 to 1,405 μg/L). Responses to each pesticide were similar among the three species. Sensitivity was generally highest for 7-day and 14-day age groups, and flowing water tests were more sensitive measures of toxicity than static tests, especially for chlorpyrifos. Comparisons of three computational methods indicate that probit and moving average methods calculate comparable LC50 estimates with the binomial method being the least uniform point estimator.

Oxygen consumption rates of grunion ( Leuresthes tenuis) embryos exposed to the petroleum hydrocarbon, benzo[ a]pyrene

Bioconcentration of [ 14C]benzo[ a]pyrene and effects of unlabeled benzo[ a]pyrene (BaP) accumulation on the routine oxygen consumption of embryonic grunion ( Leuresthes tenuis) were studied. At Day 15, bioconcentration factors over dissolved BaP levels ranged from 249 to 466. Weight-specific respiration rates at Days 14–15 were significantly increased ( P ≦ 0.05) at a mean BaP body burden of 0.51 ppm wet wt. Oxygen consumption rates of embryos containing 0.70 to 12.80 ppm BaP were not significantly different from control rates. Because in a previous study embryos containing 0.51 ppm BaP exhibited hatching and developmental rates similar to those of controls, their metabolic response to low-level hydrocarbon exposure may be an example of hormesis, an overcompensating metabolic regulation to inhibitory challenges.

Effects of temperature on interactions of physiological and behavioural capacities of larval California grunion: Adaptations to the planktonic environment

The relationship between temperature-specific (11.3–27.1°C) rates of yolk utilization and temperature preference of California grunion, Leuresthes tenuis (Ayres), have been compared. Yolk-sac larvae experienced difficulty metabolizing protein at and above 25°C, and below 15°C they encountered problems with fat metabolism. These temperatures limited the range for normal embryonic development. The oil globule persisted longer than the yolk and may provide buoyancy to the anterior end as well as energy. Thermoregulatory precision increased with number of days post-hatching. Yolk-sac larvae preferred ≈ 25°C; this temperature minimized duration of the yolk-sac stage but was outside the range for maximum growth efficiency (18–23°C). Following yolk resorption, non-feeding larvae preferred 18°C, which conserved energy but still maximized growth efficiency. Until at least 69 days post-hatching, larvae past the yolk-sac stage selected temperatures that maximized growth efficiency. Physiological and behavioural results indicate that larvae selected cooler temperatures when not feeding. This has been discussed and related to an apparent general adaptive behaviour to maximize bioenergetic efficiency.

Ovarian Changes during the Lunar Spawning Cycle of Fundulus heteroclitus

nual intervals is a relatively common phenomenon in shallow water fishes. The guppy, Poecilia reticulata and mosquitofish, Gambusia sp. produce young at approximately 30-day intervals (Turner, 1937). The California grunion, Leuresthes tenuis (Clark, 1925) has a semilunar reproductive cycle in which spawning occurs in synchrony with the spring tides of new and full moon during a reproductive season of several months. Recent field observations on the mummichog, Fundulus heteroclitus (Taylor et al., 1979)

Nosema lepocreadii sp. n., a Parasite of Lepocreadium manteri (Digenea: Lepocreadiidae) from the Gut of the California Grunion, Leuresthes tenuis

Nosema lepocreadii sp. n. is described from adult flukes Lepocreadium manteri Olson 1978 from California grunion. The microsporidia are parasitic in cells of the vitelline system. The arrangement of nuclei in diplokarya and the disporoblastic sporogony are characteristic of the genus Nosema Naegeli 1857. Schizonts with homogeneous cytoplasm and vesicular nuclei can be distinguished from sporonts that have banded cytoplasm and compact nuclei. Chain formation of schizonts or sporonts is common. Spores are 3.5 x 1.5 ,m when fresh. Lepocreadium manteri Olson 1978 (Dige- nea: Lepocreadiidae), is a parasite in the gut of the beach-spawning California grunion, Leuresthes tenuis (Ayres, 1860) (Osteichthy- es: Atherinidae). While studying this parasite, we found that several grunion contained flukes which were hyperparasitized by mi- crosporidia. The microsporidia were discov- ered during regular sampling of grunion as part of a study of the parasite fauna of these fish and in particular of Lepocreadium man- teri Olson (1978). All the microsporidian ma- terial was collected and preserved in Califor- nia by Olson. In this report the hyperparasite, believed to belong to the genus Nosema, is described at the light microscope level. Electron micro- scopic observations will be presented in a lat- er communication, where the ultrastructure will be compared with that of other Nosema species from trematodes.

Tidal influence on the evolution of egg size in the grunions (Leuresthes, Atherinidae)

The duration of natural in-beach-sand incubation of Gulf of California and California grunion embryos is dictated by the tidally-driven wave activity in their respective habitats. Analyses of these tidal regimes reveal that the incubation period can be three times longer on beaches of the California coast than on those of the northern Gulf.

Inhibited hatching success of marine fish eggs by power plant effluent

The hatching success of California grunion (Leuresthes tenuis) was significantly reduced by a non-thermal component of the effluent from an electricity generating station. The embryos appeared to develop normally morphologically but showed reduced viability with respect to hatching.

Asymphylodora atherinopsidis (Trematoda: Monorchiidae) from the California Grunion, Leuresthes tenuis, including a Redescription

Asymphylodora (Asymphylodoroides) atherinopsidis from the California grunion, Leuresthes tenuis, a new host record, and jacksmelt, Atherinopsis californiensis, the type host, is redescribed and illustrated using more symmetrical as well as larger and smaller specimens than the holotype. The geographic distribution is extended from the type locality of Stinson Beach, Marin Co., California to Estero Beach, 10 km south of Ensenada, Baja California Norte, Mexico. Two tubular externat seminal vesicles opening independently into the internal seminal vesicle are reported apparently for the first time in a trematode. The genital pore is at the left posterolateral margin of the acetabulum which is midway between the lateral margins. Worms may grow to a length of 5.6 mm but eggs were present in one specimen 1.3 mm long.

Responses of Young California Grunion, Leuresthes tenuis, to Gradients of Temperature and Light

In a laboratory temperature gradient, young California grunion, Leuresthes tenuis, exhibited a final modal preferendum of 25 C, 7 C lower than the final preferendum of young L. sardina from the Gulf of California. No circadian rhythms in thermal preference were found, and the final preferendum was unaffected by acclimation temperature. Like L. sardina, young L. tenuis were strongly attracted to bright light (10,000 lux). In a simultaneous opposed gradient of temperature and light, the fish spent more time at the preferred temperature than at the preferred light intensity. The laboratory results are discussed in relation to observed field distribution and geographic range.

Temperature and salinity tolerances of larval Californian grunion, Leuresthes tenuis (Ayres): A comparison with gulf grunion, L. Sardina (Jenkins & Evermann)

Temperature and salinity tolerances were determined for larval California grunion, Leuresthes tenuis (Ayres), and compared with previous data for Gulf of California grunion, L. sardina (Jenkins & Evermann). Larvae of similar age and acclimation history showed little interspecific difference in thermal tolerance, as measured by half-hour LT 50 values for 20–30 day old late postlarvae acclimated at various temperatures, and by upper and lower incipient lethal temperatures for 18°C-acclimated prolarvae. The upper incipient lethal temperature differed by 1 deg.-C (32°C for L. tenuis, 31°C for L. sardina), while the lower incipient lethal temperature for the 18°C acclimated prolarvae of both species was 7.5°C. L. tenuis larvae were much less euryhaline than L. sardina, with incipient lethal salinities of 4.2–41 %. for prolarvae and 8.6–38 %. for 20-day-old postlarvae; comparable values for L. sardina are 4–67.5 %. and 5–57.5 %. Both species show a decrease in temperature and salinity tolerance with age. The larvae of these disjunct congeners show a significant physiological divergence in euryhalinity but not in overall temperature tolerance. These tolerances are discussed in relation to the respective geographic ranges and behavioral responses of the two species.

Ontogenetic change in the response of the Gulf of California grunion, Leuresthes sardina (Jenkins & Evermann), to a salinity gradient

Larval and juvenile Gulf of California grunion, Leuresthes sardina (Jenkins & Evermann), hatched and reared in the laboratory, were subjected to salinity gradients in a Staaland salinity gradient device to determine their locomotive responses. Newly hatched prolarvae selected salinities in the range 15–24‰, while late postlarvae and juveniles preferred salinities in the range 45–54‰. Early postlarvae exhibited a bimodal preference, indicating that the behavioral change was in progress at that age. These behavioral responses may serve several functions in the physiological and behavioral ecology of the Gulf grunion.

Some influences of temperature on the rearing of the grunion Leuresthes tenuis, an atherine fish

Grunion Leuresthes tenuis (Ayres), an atherine fish, were reared, from artificially fertilized eggs to 160 days posthatching, at temperatures from 18.0° to 25.4° C. The rearing was carried out in five 60 l rectangular containers and two hard moulded plastic pools holding 60 and 450 l. The growth rate was highly correlated with temperature at least up to metamorphosis. Thereafter, the effect of temperature on growth, within lethal limits, appeared to be lost or at least masked by other factors. At low densities, after metamorphosis, growth was proportional to the population density. Size and shape of the rearing containers also influenced the growth rate.

Effect of Temperature on Number of Myomeres in Newly Hatched Grunion (Leuresthes tenuis)

Effect of Temperature on Number of Myomeres in Newly Hatched Grunion (Leuresthes tenuis)

Lactic acid response in the grunion

1. 1. Lactic acid levels in blood and muscle have been determined in a fish ( Leuresthes tenuis) which spawns out of water. 2. 2. Out of water, lactic acid builds up in the muscles but little enters the blood. 3. 3. During recovery in water there is an acute lactic acid rise in the blood and a slow drop in the muscle lactate. 4. 4. This is interpreted to mean that the muscles remain ischemic during the asphyxia and build up lactic acid which flushes out by the hyperemia in recovery. 5. 5. This mechanism of asphyxial defense is an analogue to the cirulatory changes found in diving and non-diving animals and man.

The Influence of Light on the Number of Vertebrae in the Grunion, Leuresthes tenuis

vertebrae in fishes can be influenced by environmental factors, notably temperature and salinity, during the early developmental stages (Schmidt, 1918, 1919, 1920, 1921; Thning, 1944, 1952; Heuts, 1946). Undoubtedly other environmental factors produce similar effects (Vladykov, 1934; Johnsen, 1936), although investigations along these lines have not been extensive. Dannevig (1932) has suggested that the number of vertebrae in the cod may be influenced by light intensity, and it has been stated (Worth, 1898) that the hatching of shad eggs is speeded in direct sunshine, and that continuous dark and cloudy days will retard, and strong light will accelerate, development under equal conditions of temperature. Willer (1928) also has found that light affects the rate of development of fishes. More recently, Hoover and Hubbard (1937) have found that the sexual cycle in trout can be modified by control of light, and this knowledge has been put to practical use by the Fish and Game Department of New Hampshire (Bernard W. Corson, personal communication). The experimental results reported here can not be considered conclusive. Nevertheless, they bear on the results of investigations shortly to be reported, and add to the scanty literature relating to the effect of light on animal development. The experiments were designed originally to determine the effects of temperature and salinity on mean vertebral number in the grunion, Leuresthes tenuis (Ayres). It soon became apparent that the results were too variable to be of value for this purpose. In searching for the cause of this variability, it was realized that the amount of light falling on the experimental lots was not under control, and a further experiment was conducted to investigate the effects of this factor. Eggs from a single female were fertilized in the laboratory by sperm from a single male. The fertilized eggs were separated into three lots and were placed in beakers of sea water. The three beakers were immersed in water in a I Contributions from the Scripps Institution of Oceanography, New Series, No. 636. 23

The comparative effects of teleost and beef pituitary on chromatophores of cold-blooded vertebrates.

1. Fish and beef acetone-desiccated pituitaries cause a distal migration of pigment granules in melanophores when injected into the elasmobranch Urobatis halleri, the teleost Ameiurus melas, the amphibians Hyla regilla and Rana pipiens, and the reptile Anolis carolinensis. These preparations not only disperse melanin but also induce a proximal migration of the white granules in leucophores of Rana pipiens larvae.2. Fish pituitary injected into the teleosts Gambusia affinis, Fundulus parvipinnis, Girella nigricans, Gillichthys mirabilis, Lepomis cyanellus and Leuresthes tenuis causes a proximal migration of melanin and, at least in the first three species, a distal migration of pigment in the xanthophores. Desiccated fish brain, beef whole gland, beef posterior lobe and commercial pituitrin have no obvious effect on their chromatophores.3. There is an opposite migration of melanin in certain different species of teleosts treated with fish pituitary. The diverse chromatic reaction of teleosts may have phylogenetic significance. The more primitive teleosts appear to react like other classes of cold-blooded vertebrates, whereas the higher teleosts, which have diverged more from the common line of vertebrate evolution, do not.4. There is a differential in reaction of different types of chromatophores in a single species to treatment with the same pituitary preparations.5. Pituitary material from different sources may have unlike chromatophorotropic action. Beef and fish pituitary have a similar action (expansion) on melanophores of Urobatis, Ameiurus, Rana and Anolis. However, on such teleosts as Fundulus and Girella, fish extracts have the opposite effect and mammalian extracts have no apparent effect.

Embryonic and Early Larval Stages of the Grunion, Leuresthes tenuis, and of the Sculpin, Scorpaena guttata

Embryonic and Early Larval Stages of the Grunion, Leuresthes tenuis, and of the Sculpin, Scorpaena guttata