Showing papers by "National Marine Fisheries Service published in 1987"

Wind Speed and Mortality Rate of a Marine Fish, the Northern Anchovy (Engraulis mordax).

Abstract: Large variability in recruitment of marine fishes creates challenging management problems. In northern anchovy (Engraulis mordax), there is a significant linear relation between larval mortality rate and the frequency of calm, low wind speed periods during the spawning season, possibly because calm winds permit maintenance of concentrated patches of larval food. Neither cannibalism on larvae nor offshore transport contributed significantly to interannual variation in early larval mortality. These results are consistent with the hypothesis that wind-driven turbulent mixing affects variability in survival of young fish larvae. However, abundance of recruits does not necessarily reflect abundance of larvae surviving through this early stage.

Measurement of free cupric ion concentration in seawater by a ligand competition technique involving copper sorption onto C18 SEP-PAK cartridges1

Abstract: Knowledge of ion speciation and free ion concentrations is important in predicting the biological availability and geochemical behavior of trace metals. Here we describe a new technique for measuring free cupric ion concentration in seawater based on sorption of copper onto SEP-PAK C,, cartridges and internal free cupric ion calibration. Calibration was achieved by adding cupric ion buffers, consisting of copper and excess concentrations of synthetic chelator, ethylenediaminetetraacetic acid (EDTA). EDTA competes with natural organic ligands for copper complexation, but its copper chelate is not retained by the C,, cartridges. This latter property allows EDTA to bc used for free cupric ion calibration. Titrations in seawater utilizing the new technique revealed that copper was highly complexed. Fret cupric ion concentrations in three samples of seawater from lower Narragansett Bay, Rhode Island, and one from off the coast of Peru were measured to be 10-12.3, 10 -120, 10 12.L, and 1O-“.5 M at total dissolved copper concentrations of 26.7, 16.5, 19.4, and 3.7 nM. From these values and from computed and experimental values for inorganic complexation, we compute that only 0.03-2% of the dissolved copper can be accounted for as inorganic species (Cu2+, CuCO,, CuOH’, etc.). The remainder, 99.97-98%, appears to bc organically complexed. These results are in general agreement with several other recent studies, using several techniques, of copper complexation in seawater.

Microbial oxidation of manganese in a North Carolina estuary

Abstract: Experiments were conducted with 54Mn(II) to determine the kinetics of particulate manganese formation in seawater from the lower Newport River estuary, North Carolina. Dissolved Mn was rapidly converted into particles at constant rates that ranged from 0.36 to 6.2% h-r (0.62-3.5 nmol liter-l h-l), yielding turnover times of the dissolved manganese pool of 0.7-l 1 d. Dissolved Mn turnover rates increased with temperature (Q10 = 2) up to a maximum at 25”-35°C and also increased with the ratio of particulate to dissolved Mn. These two factors explained most of the variation in the observed turnover rates. Sample deoxygenation reduced the formation of particulate 54Mn by 94% and virtually all the particulate 54Mn formed in natural oxygen-containing samples could be dissolved by 10 PM ascorbic acid, a strong reducing agent. These results indicated that the formation of particulate 54Mn resulted primarily from the oxidation of Mn(I1) to manganese oxides (MnO,). The oxidation rates, however, were much too rapid to be accounted for by abiotic mechanisms, and the rate was reduced by 97% following heat sterilization of the seawater. In addition, the rates conformed to the Michaclis-Menten enzyme kinetics model with V,,, equal to 1.2 x lO-8 mol liter-’ h-’ and K, equal to 1.9 x lo-’ M. These findings provide strong evidence that oxidation of Mn in the estuarine samples is microbially catalyzed. This catalysis appears to be instrumental in the rapid redox cycling of Mn and in the scavenging of dissolved Mn onto particles in aquatic systems.

Effects of cupric and zinc ion activities on the survival and reproduction of marine copepods

Abstract: The toxicity of copper and zinc to the estuarine copepod Acartia tonsa and to the two diatom food species Thalassiosira pseudonana and T. weissflogii was measured in nitrilotriacetate-trace metal ion buffer systems at 25‰ S. Overall, A. tonsa appeared to be more sensitive to cupric and zinc ion activity than either of the diatoms; however, its sensitivity varied among the different life stages examined. Adult survival was not affected within the zinc ion activity range 10-11 to 10-8M and cupric ion activity range 10-13 to 10-11M over a 96-h period, but a cupric ion activity of 10-10M caused total mortality of adults within 72 h. Egg-laying rate was most sensitive to zinc, and was reduced at zinc ion activities ≧10-10M. Naupliar survival after 96 h was reduced by zinc ion activities ≧10-8M and by cupric ion activities ≧10-11M, and was reduced to zero at a zinc ion activity of 10-7M and at a cupric ion activity of 10-10.5M. In an interspecies comparison of 96-h adult survival, Centropages typicus was more sensitive to copper and zinc than A. tonsa and the survival of Labidocera aestiva was dependent on the ratio of cupric to zinc ion activity. A comparison of our results with estimates of zinc and cupric ion activities in estuaries suggests that ionic activities of these metals are high enough in some polluted estuaries to affect the survival and reproduction of copepods.

Latitudinal variation in the Dungeness crab, Cancer magister: zoeal morphology explained by incubation temperature

Abstract: The difference in morphology between zoeae of Cancer magister Dana from Alaskan and Californian waters was documented to determine if the morphological variation is attributable to environmental influences First-stage zoeae from Alaska have significantly longer carapace spines than zoeae from central California The dorsal, rostral and lateral carapace spines were 14, 14 and 29% longer, respectively, in the Alaskan zoeae The effect of temperature was tested on zoeal morphology as it is an obvious environmental difference between Alaskan and Californian waters Ovigerous female crabs collected in southeastern Alaska in 1984 were held at 1°, 5°, 10° and 15° C until hatching occurred Eggs were sampled seven times during the incubation period, and relative mortality, egg diameter and development stage were measured All of the crabs and eggs at 1° C died before hatching occurred Egg mortality averaged less than 2% in the other temperature treatments Egg diameter increased significantly over the incubation period for all temperatures Developmental rate of the embryos was inversely related to temperature Hatching first occurred in 42 d at 15° C, 60 at 10° C and 160 d at 5° C Newly hatched zoeae were collected and body length, dorsal, rostral and lateral carapace spines were measured Significant differences existed between all temperatures for all spine lengths, with longer spines occurring at lower temperatures Zoeal body lengths were also significantly different between the three temperatures The results of this study question the use of spine lengths to distinguish similar larval species

A review of fixed phagocytic and pinocytotic cells of decapod crustaceans, with remarks on hemocytes.

Abstract: Clearance of foreign materials from the hemocoel of decapod crustaceans involves several distinct kinds of cells. Proteins, and possibly viruses below 30 nm diameter, are known to be removed by the branchialpodocytes, which are specialized pinocytotic nephrocytes located in the gills. These cells, and podocytes of the antennal gland (excretory organ) which may also be of importance in clearance, are similar to podocytes of Bowman's capsule of the vertebrate kidney. Phagocytic clearance of particulate material (with possible exception of the small viruses) is accomplished by three kinds of cells, one free and the other two fixed to tissues facing hemal spaces. The hemocytes, free cells suspended in the hemolymph, are the most abundant and generalized of these phagocytic cells. Phagocyticreservecells are applied to myofibers in the heart of penaeid and palaemonid shrimp, and probably the same as reserve cells found throughout the hemocoel of all decapods. They are minimally involved in clearance of injected carbon and carmine, but are not known to phagocytize naturally occurring particles such as bacteria or viruses. The fixedphagocytes are very important in the clearance of some substances. They are located on the exterior surfaces of arterioles in hemal spaces of the hepatopancreas. They are highly specialized cells designed to sequester large amounts of various types of particulate matter, not only through phagocytosis but by trapping and retaining vast numbers of particles within a net- or sievelike layer of granular material which surrounds the free surface of the fixed phagocyte. Derivation, morphology, development, and function of the above cell types are described and discussed.

Absorption, body distribution, and excretion of dietary zinc by rainbow trout (Salmo gairdneri).

Abstract: Rainbow trout (Salmo gairdneri) were held in metabolizable energy chambers at Standard Environmental Temperature (15°C) for 72h following a single feeding of a semi-purified test diet containing tracer quantities of a radioisotope of zinc (65Zn) and different combinations of dietary calcium level and zinc source. Gill wastes, urine, and feces were separately collected. After 72h, the fish were killed, and samples of the following tissues removed: eyes, skin, muscle, blood, bone, liver, bile, kidney, gill, spleen, stomach, pyloric caeca, intestine, gonad, and remaining carcass. Radioactivity in the tissues and wastes was determined and the body distribution of the ingested zinc was quantified. Approximately 58% of the administered dose of65Zn was recovered. Of the recovered dose, 43.2% was present in the gastro-intestinal tract, 27% in the feces, 14% in the gill water, 16% in the body of the fish, and less than 1% in the urine. Of individual tissues, the gill, liver, kidney, and spleen had concentrations of65Zn higher than blood, while the remaining tissues had lower concentrations. Body and tissue levels were increased but not significantly by feeding65Zn as an amino acid chelate, compared to feeding as inorganic65Zn, while dietary calcium level had no effect. The results of this study indicate that the gills play a major role in excretion of dietary zinc, while the urine plays a minor role.

Phosphorus Deficiency in Rainbow Trout Fed a Diet Containing Deboned Fillet Scrap

Abstract: Whole Pacific hake (Merluccius productus) and hake fillet scrap were ground, heated to accelerate enzymatic hydrolysis, and acidified to prevent microbial degradation Half of the fillet scrap was screened to reduce the bone content of the product After 10 d of storage, the liquefied products were combined with feather meal and dried The dried products replaced fish meal in practical diets, which were fed to rainbow trout (Salmo gairdneri) for 22 weeks Significant reductions in plasma phosphorus and whole-body and vertebral calcium, phosphorus, and magnesium concentrations were found in rainbow trout fed the diet containing the deboned fillet scrap, while fish fed a phosphorus-supplemented diet had levels similar to fish fed the diets containing whole fish Plasma alkaline phosphatase activity was unaffected by diet Rainbow trout fed a diet containing unscreened fillet scrap were similar in all respects to fish fed a diet containing whole fish This study shows that the high dietary ash prese

Epizootic characteristics of hepatic and renal lesions in English sole, Parophrys vetulus, from Puget Sound

Abstract: English sole, Parophrys vetulus, from eight locations within Puget Sound, U.S.A. were examined for histological abnormalities of the liver and kidney. A total of 1083 fish were collected between February 1979 and June 1984 in nine separate sampling periods. Idiopathic lesions, i.e. lesions of unknown cause, were classified into eight hepatic and four renal lesion categories. The significance of certain potential risk factors associated with lesion prevalences, including age, gender, site of capture, season of capture and year of capture, were assessed by logistic regression. The odds ratios for the significant risk factors were also calculated. Site of capture and age of the examined fish were found to be the most important factors for most of the observed lesion types, e.g., hepatic neoplasms and foci of cellular alteration, whereas year and season of capture were significant influences for only a few lesion types, e.g., specific and nonspecific degenerative/necrotic lesions of the liver. Gender of examined fish was not found to be a significant factor for any of the lesion types. These results emphasize the importance of including certain potential influences, such as age and season of capture, in the analysis of field-collected organ pathology data.

Behavioral responses of red hake,Urophycis chuss, to decreasing concentrations of dissolved oxygen

Abstract: Laboratory experiments were conducted to examine changes in behavior of red hake,Urophycis chuss, under decreasing concentrations of dissolved oxygen (DO). Since the ecological requirements of this species change with age, responses were measured for three different groups: (1) age 0+, = 89 mm total length (TL); (2) age 1+, = 238 mm TL; and (3) age 2–3+, = 397 mm TL. As DO decreased from 8–10 mg l-1 to < 0.5 mg l-1, changes were evident in active time, water column activity, range of horizontal movement, food searching, and agonistic behavior. Age 0+ fish were most sensitive, moving up into the water column and swimming continuously as DO levels fell below 4.2 mg l-1. Age 2–3+ fish were the least responsive, remaining on the substrate and increasing only their range of movement at concentrations below 3 mg l-1. Responses of age 1 + fish were variable, possibly reflecting a transition stage between the younger and older fish. Common to all groups was the decrease and eventual cessation of food searching.

Relative abundance, distribution and inter-specific relationship of cetacean schools in the eastern tropical pacific

Abstract: The relative abundance of the most common cetacean schools in the eastern tropical Pacific Ocean for 1977–1980 are estimated based on encounter rates with tuna purse-seiners. No temporal trends were apparent in the relative abundance estimates. The geographic distributions for eight different school types are described. Multivariate statistical techniques are used to investigate interrelations between species and relationships to parameters of the physical environment. The results suggest three major species groupings: (1) an inshore grouping of bottlenose dolphins (Tursiops truncates), Risso's dolphin (Grampus griseus), pilot whales (Globicephala macrorhynchus) and, to a lesser extent, common dolphins (Delphinus delphis); (2) an offshore pelagic grouping of spotted and spinner dolphins (Stenella attenuate and S. longirostris); and (3) an association between pilot whales and common dolphins that overlaps the first grouping in inshore areas and also tends to be segregated from the second grouping. The results also suggest that relative densities of different school types are strongly related to physical environmental parameters, the most important being sea surface temperature, depth of the thermocline and thickness of the oxygen minimum layer.

Age and Growth of the Warsaw Grouper and Black Grouper from the Southeast Region of the United States

Abstract: Opaque rings on sectioned otoliths from warsaw grouper, Epinephe/us nigritus (N = 124), and black grouper, Mycteroperca bonaci (N = 172), were used to estimate age and growth. The aging structures from warsaw grouper were obtained by dockside sampling of headboat landings from North Carolina through the Florida Keys. Black grouper were sampled from headboat landings primarily in the Florida Keys. Annulus formation occurred between April and May for warsaw grouper, and from March through May for black grouper. The weight-length relationship for warsaw grouper is W = 2.09 x 10-5L2.9797, and for black grouper is W = 5.548 x 10-6L3.141, where W = weight in grams and L = total length in millimeters. Mean back-calculated total lengths for warsaw grouper ranged from 292 mm at age 1 to 2,328 at age 41, and from 260 mm at age 1 to 1,110 mm at age 14 for black grouper. The von Bertanlanffy growth equation for warsaw grouper is L1 = 2,394 (1·e-0.0544(1 + 3.616)), and for black grouper is L1 = 1,352 (1·e-0.1156(1 + 0.927J, where t = age in years and L = total length in millimeters. Both species have growth characteristics that are similar to most other serranids studied along the southeastern United States. Catch curves and a yield-per-recruit model are presented for black grouper.

Fish population responses to chronic and acute pollution: The influence of life history strategies

Abstract: We have developed a simulation model to estimate pollution effects on economically important estuarine-dependent fish populations. Traditionally, pollution studies have focused upon impacts on individual organisms; however, wise management of marine resources depends upon an understanding of dynamics at the population level. As a required first step toward conducting relevant pollution studies, we have compiled available life history data on eight species (14 spatial-temporal stocks), concentrating on age-specific rates of growth, survival, and fecundity. Leslie matrix models of species population dynamics were used to predict pollutant impacts—mediate through changes in 1st-year survival. On average, and without compensation, these modelled stocks respond to a one-time-50% reduction in first-year survival by taking ten years to equilibrate at 88% of their preimpact abundance. Our synthesis of the data included a search for derived (standardized) population parameters to evaluate differences in susceptibility among and within fish populations to pollutant stresses. We demonstrated that knowledge of a species’ age-specific fecundity pattern provides additional predictive power of its response to pollution perturbation.

Comparison of the fatty acid component in structural lipids from dolphins zebra and giraffe: possible evolutionary implications

Abstract: Essential fatty acid compositional data on the structural lipids of mammals which predominantly eat n-3 fatty acids suggests preferential incorporation of n-6 essential fatty acids. The structural lipids of liver, muscle and brain of five species of dolphin (Tursiops truncatus, Stenella allenuata, Steno bredanesis, Delphinus delphis and Lagenorhynchus obliquidens), obtained from the wild, contained substantial amounts of arachidonic acid and other n-6 long chain derivatives of linoleic acid. The n-6 to n-3 ratio was approximately 1:1. Data for two species of leaf-eating land mammals, the zebra, Equus burchelli Gray and giraffe, Giraffa camelopardalis L., indicate that tissue phosphoglycerides were dominated by n-6 fatty acids.

Growth of Tilapia aurea in Seawater Cages

Abstract: Fingerling Tilapia aurea were reared for 90 days in three 1.0 m3 floating cages in seawater (36 ppt) at Lee Stocking Island, Bahamas. Fish stocking density (100, 200 and 400 fish/m3) apparently did not affect growth rate but it appears salinity inhibited growth. Daily weight gain and specific growth rate (G) averaged 0.34 g/day and l.08%/day, respectively, for Tilapia aurea fingerlings. Infection of the Tilapia aurea by Bacillus sp. was associated with a significant number of mortalities. The relatively low growth rate and the high incidence of disease and mortality of Tilapita aures in seawater indicate that it may not be a good candidate for cage culture in full-strength seawater.