Increasing Fish Size Research Articles

Size dependence of zinc elimination and uptake from water by mosquitofish Gambusia affinis (Baird and Girard)

Zinc-elimination rate constants decreased with increasing fish size as described in the equation k e = 0.001 (dry wt.) −0.42. One compartment displaying a median biological half-life of 215 days was identified. Additional compartments were not discernable using backstripping methods. Zinc-uptake rates from water also decreased with increasing fish size. The equation describing this relationship was k u = 0.029 (dry wt.) −0.90. Size-dependent relationships for body burdens of Zn in G. affinis were derived by combining the effects of size-dependent uptake from water and elimination kinetics. A non-equilibrium approach incorporating fish size and duration of exposure was used to generate relationships between fish size and Zn-body burden with exponents ( b values) less than 1. As duration of exposure increased, the b values for the size-dependent body-burden relationships also increased.

Size related toxicity of industrial effluents to cyprinus carpio (HAM.) and Channa punctatus (BL)

AbstractFish, Cyprinus carpio and Channa punctatus in four sizes (6.0 ± 1.2; 12.5 ± 1.6; 20.6 ± 1.5 and 28.0 ± 1.8 cm in total length) were exposed to industrial effluents from the Sangam Dyeing Factory (Ludhiana), the Sterling Steel and ABC Paper Mills (Hoshiarpur) to evaluate the acute toxicity of these effluents at different fish sizes. Results reveal that the toxicity of industrial effluents decreased with the increased fish size from 6.0 ± 1.2 to 20.6 ± 1.5 cm in length. However, for specimens of the size of 28.0 ± 1.6 cm and more, the toxicity of the effluents increased with an increase in fish size. On the basis of the relative toxicity to fish, effluent from the Sterling Steel Mill was found to be highly toxic to fish and effluent from the Dyeing Factory least toxic except for the fish of 6.0 ± 1.2 cm at which dyeing factory effluent was most toxic and ABC paper mill effluent the least toxic.

Food-Induced Granulomatosis in European Smelt, Osmerus eperlanus

Many European smelt, Osmerus eperlanus, in tributary rivers to the North Sea are affected by granulomatosis in the buccal cavity. The granulomas are caused by spines and leg fragments of amphipods, an important food item of smelt. Granuloma prevalence increases with increasing fish size. The rate of increase slows down in very large fish, probably as an effect of changed feeding habits. Fungi and virus-like particles in the granulomas are assumed to be secondary invaders. Granulomas are occasionally found in Atlantic cod, Gadus morhua, and flounder, Platichthys flesus, also.

Effects of Riprap Bank Reinforcement on Juvenile Salmonids in Four Western Washington Streams

Abstract Summer and fall juvenile salmonid populations in five pairs of stream sections were estimated shortly before and after construction of flood and erosion control projects. All five projects included bank reinforcement with rock riprap and three included streambed alterations. Juvenile coho salmon Oncorhynchus kisutch, juvenile steelhead Salmo gairdneri, and cutthroat trout Salmo clarki were apparently adversely affected by construction in the three smaller, and most severely altered, stream sections. Numbers of juvenile coho salmon and young-of-the-year trout were reduced somewhat, but those of yearling steelhead and cutthroat trout apparently increased, in the two newly riprapped sections of larger streams. Negative short-term effects of construction appeared to increase with severity of habitat alteration, to decrease with increase in stream size, and to decrease with increasing fish size.

Acute Toxicity of Some Industrial Effluents in Relation to the Fish Size of Cyprinus carpio (HAM.) and Channa punctatus (BLOCH)

AbstractThe fish Cyprinus carpio (HAM.) and Channa punctatus (BL.) of the size ranging between 6.0 ± 1.2 cm and 28.0 ± 1.6 cm were exposed to different concentrations of industrial effluents from M/s Punjab Tannery Ltd. (Jalandhar), M/s Spinning Mill Ltd. (Hoshiarpur) and M/s Food Specialist Ltd. (Moga) for evaluating the influence of fish size on the acute toxicity of these effluents. Results indicate that the relative toxicity of the effluents decreased with the increase in fish size from 6.0 ± 1.2 cm to 20.6 ± 1.5 cm. However, for specimens of the size of 28.0 ± 1.6 cm and more, the toxicity of the effluents increased with an increase in fish size. On the basis of the relative toxicity to fish, effluent from Punjab Tannery was found highly toxic and from Food Specialist Industry, the least toxic.

Possible use of taxonomic characters to identify Newfoundland and Scottish stocks of Atlantic salmon, Salmo salar L.

. Based on a pooled sample of 367 specimens of juvenile Atlanlic salmon, Salmo salar L., from eight geographically distinct home rivers, stocks from Scotland and Newfoundland can be distinguished by meristic and morphometric character sets using discriminant analysis procedures. Reduced character sets require meristic counts of pectoral fin rays, dorsal fin rays, gill rakers and vertebrae, and morphometric measurements of standard length, pectoral and pelvic fin lengths, body depth and gape width. Regional differences based on these morphometric and meristic sets are substantiated by monomorphism at each MDH locus in Scottish fish in contrast to polymorphism at the MDH-1 and MDH-3 loci in Newfoundland fish. Only the morphometric discriminant function is highly accurate (>80%) in identifying home river origins of the fish examined with the discriminating power increasing with increased fish size. These findings for juvenile fish indicate that, while meristic, morphometric and electrophoretic criteria provide a likely means for distinguishing regional fish stocks, morphometric character sets would seem to offer the best possibility for identifying home river origins of adult Atlantic salmon in mixed fisheries.

Seasonal occurrence of metazoan parasites of Puntius binotatus in an irrigation canal, Pulau Pinang, Malaysia

Two hundred specimens of the cyprinid fish Puntius binotatus were collected over a period of 1 year, February 1976–January 1977, from an irrigation canal in Palau Pinang, Malaysia. Six species of parasites were recovered: Dactylogyrus sp., Rhabdochona penengensis Furtado, 1965; Proteocephalus sp., Bothriocephalus acheilognathi Yamaguti, 1934, Pallisentis gaboes MacCallum, 1918 and Lamproglena minula Capart, 1943. The prevalence and mean density of two ectoparasites (Dactylogyrus sp. and L. minuta) and an endoparasite (B. acheilognathi) were examined in relation to season and host size. Fish were found to be free of these parasites in many months of the year. Prevalence and mean density of Dactylogyrus sp. and L. minuta were found to be highest during the early part of wet season, whereas those of B. acheilognathi were found to be highest in the later part of wet season. Prevalence of L. minuta increased with increasing size offish, but mean density was least in the largest fish. Both prevalence and mean density of B. acheilognathi were highest in smaller fish, whereas that of Dactylogyrus sp. showed little variation in the three size–groups.

Accumulation of zinc by rainbow trout as influenced by pH, water hardness and fish size

AbstractThe intrinsic toxicity of zinc within fish may be defined as the amount of zinc present in the gills (the site of acute toxicity) at death. This intrinsic toxicity was similar in rainbow trout (Salmo gairdneri Richardson) that were exposed to zinc in acid or neutral water (pH 5.5 or 7.0) and in hard or soft water (total hardness 390 or 30 mg CaCO3/L). Since much more zinc was needed in the water to cause death at low pH and at high hardness, these conditions must alter the uptake and/or excretion dynamics of zinc in gill tissue to produce a slower rate of zinc accumulation. Additional evidence supporting this conclusion is presented. A 17‐fold increase in fish size, from 1.7 to 29.0 g, reduced tolerance of zinc by a factor of 3.2, whereas a 14‐fold increase in fish size, from 1.3 to 18.2 g, reduced the median lethal time by a factor of 2.7. This reduced tolerance and resistance in larger fish appeared to result from increased intrinsic toxicity of zinc. All sizes of fish showed similar rates of zinc accumulation in the gills, of about 40 μg/g · h.

Random Prey Capture or Active Choice? An Experimental Study on Prey Size Selection in Three Marine Fish Species

Prey size selection was studied in the marine fishes Pomatoschistus microps, P. minutus, and Platichtys flesus. Three size classes of the amphipod Corophium volutator were used as prey in laboratory experiments, and field samples were taken to compare Corophium size in the fish stomachs and in the surrounding environment. When there were equal numbers of the different prey sizes in the aquaria, P. minutus and P. flesus ate an increasing proportion of large Corophium as prey density increased. P. microps were offered the Corophium size-classes in different proportions. When there were equal numbers of the size-classes, P. microps showed a strong preference for large prey, but as small prey increased in abundance, selectivity decreased and prey choice became random. In the field, small Corophium were more abundant than the other size-classes. P. microps and P. minutus ate this prey most frequently, while P. fiesus ate more medium-sized Corophium. For P. minutus and P. flesus mean prey size increased with increasing fish size in the laboratory experiments. Prey size selection was thus influenced by absolute and relative densities of prey and by predator size. Differences in visibility and evasion capability of different sizes of prey also affected the food choice of the fishes in this study.

Pathogenesis of Trypanosoma murmanensis in marine fish of the northwestern Atlantic following experimental transmission

The susceptibility of four species of marine fish (Gadus morhua, Pseudopleuronectes americanus, Myoxocephalus scorpius, and Myoxocephalus octodecemspinosus) to leech-transmitted Trypanosoma murmanensis was assessed 49–60 days after infection by comparing condition factor, organ somatic indices, parasitological, hematological, and histological findings with corresponding uninfected animals. The fish were maintained at temperatures (0–1 °C) to simulate the environment where transmission occurs naturally. High mortality occurred in juvenile Atlantic cod and winter flounder, but deaths decreased with increasing fish size. No adult fish died except flounder when fin rot was present. Anemia was the most common pathological feature observed in young fish at necropsy, but its severity was not always correlated with the level of parasitemia. The persistent anemia was probably associated with an inactive rather than an impaired hemopoietic system. Condition factor and somatic indices of liver, spleen, and heart were altered in some infected fish groups. It is concluded that T. murmanensis is a potential pathogen, especially to juvenile American plaice, Hippoglossoides platessoides, in which high prevalences of natural infections have been observed in some areas of the northwestern Atlantic Ocean.

THE EFFECTS OF FEEDING RATES ON THE DYNAMICS OF GROWTH OF BLACK DRUM AND SPOT CAGE CULTURED IN A HEATED WATER LAKE

ABSTRACTBlack drum (Pogonias cromis) and spot (Leiostomus xanthurus) were cage cultured in a cooling lake of a power plant near Baytown, Texas, from June through September 1978 and June through November 1977, respectively, to determine the effects of varying feeding rates on the dynamics of growth. Temperature, salinity, pH and dissolved oxygen were monitored daily and fish were measured and weighed either monthly or at two‐week intervals to determine growth rates.Survival was poor for spot due to handling stress, and excellent for black drum. Instantaneous growth rates were correlated to temperature, salinity, fish size, and feeding rate. Mean food conversion efficiency (FCE) was correlated to size and feeding rate. Maximum growth rates occurred at temperatures between 27–30°C. Growth rates increased with increasing salinity, and large fish grew faster at higher salinities than small fish. Growth rates increased with increasing feeding rates up to and slightly beyond the maximum daily ration, then declined. FCE decreased curvilinearly with increasing ration up to the maximum daily ration, then remained stable. Growth rates and FCE declined curvilinearly with increasing fish size.

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

ACCUMULATION OF ZINC BY RAINBOW TROUT AS INFLUENCED BY pH, WATER HARDNESS AND FISH SIZE

The intrinsic toxicity of zinc within fish may be defined as the amount of zinc present in the gills (the site of acute toxicity) at death. This intrinsic toxicity was similar in rainbow trout (Salmo gairdneri Richardson) that were exposed to zinc in acid or neutral water (pH 5.5 or 7.0) and in hard or soft water (total hardness 390 or 30 mg CaCO3/L). Since much more zinc was needed in the water to cause death at low pH and at high hardness, these conditions must alter the uptake and/or excretion dynamics of zinc in gill tissue to produce a slower rate of zinc accumulation. Additional evidence supporting this conclusion is presented. A 17-fold increase in fish size, from 1.7 to 29.0 g, reduced tolerance of zinc by a factor of 3.2, whereas a 14-fold increase in fish size, from 1.3 to 18.2 g, reduced the median lethal time by a factor of 2.7. This reduced tolerance and resistance in larger fish appeared to result from increased intrinsic toxicity of zinc. All sizes of fish showed similar rates of zinc accumulation in the gills, of about 40 μg/g · h.

Migrating haemulid fishes as a source of nutrients and organic matter on coral reefs1

Juvenile french and white grunts (Haemulon flavolineatum and Haemulon plumieri) rest over coral colonies during the day and feed only at night in surrounding seagrass beds. We examined the amount of nitrogen, phosphorus, particulate organic carbon, and calories which these fishes deposited over the coral colonies that were their resting sites. Weight‐specific rates of nitrogen excretion by grunts decreased with increasing fish size. Rates of phosphorus excretion were not related to fish size. Excretory products were rich in nitrogen (molar N:P = 48), primarily ammonium, whereas fecal material was richer in phosphorus (N:P = 8). Feces leached over half of their phosphorus content within the first day. Half of the daily excretion and defecation occurred during the first 4 h after grunts returned to the reef, in which time they doubled the amount of NH4+ available to corals under calm conditions. Seasonal patterns of nutrient and particulate organic carbon (caloric) input to coral colonies varied with grunt biomass on the colony. The maximum input to colonies of Porites furcata from grunts occurred during August, which coincided with the time of highest coral growth rate. Grunts deposited an average of 164 and 251 mg m−2 d−1 of particulate organic carbon (feces) on the P. furcata and Acropora palmata colonies over which they rested, an energy supplement to the colonies of 0.8 and 1.2 kcal m−2 d−1. Rates of nutrient and organic matter input from grunts are comparable to or greater than rates observed in other naturally or artificially enriched ecosystems.

The Age and Growth of Young-of-the-Year Spot, Leiostomus xanthurus Lacépède, in South Carolina

Young-of-the-year spot,Leiostomus xanthurus, were sampled in Town Creek of North Inlet Estuary, South Carolina, with towed plankton nets, seines, and stationary block nets from February 14 to May 2, 1981. Age estimates obtained by analysis of daily growth increments in the sagittal otoliths showed that these fish hatched between late November 1980 and mid-February 1981. The youngest spot was estimated to be 60 days old, indicating a prolonged migration period from offshore spawning grounds. Age-length regressions permitted calculations of growth and estimates of age from standard length measurements. An increase in growth rate was observed with an increase in size of fish; however, growth of fish of equal sizes was lower in April and early May than in February and March. Age estimates suggested that the hatching period for young-of-the-year spot was concentrated between late November and mid-January. Recruitment of three separate cohorts into Town Creek occurred at approximately monthly intervals, and immigration of each cohort into the estuary took place approximately 2 months after its estimated date-of-hatch.

Changes in Elemental Composition of Hatchery-Reared Rainbow Trout,Salmo gairdneri, Associated with Growth and Reproduction

By examining a group of rainbow trout (Salmo gairdneri) over their life cycle (ova to 1500 g), 1 found that their elemental composition was determined by fish size, stage of life cycle (prefeeding, juvenile, post-juvenile), and reproductive state. Fish were fed practical diets and were reared under hatchery conditions. Whole body elemental concentrations of Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr, and Zn were size dependent prior to sexual maturity. Rates of elemental accumulation in relation to weight gain were higher in juveniles than in adult fish. Reduced somatic concentrations of Mn, Fe, and Zn were observed during gonad maturation in female but not in male trout. Tissue concentrations of some elements remained constant over the duration of the study, while others increased or decreased linearly with increasing fish size. Tables and equations 1 present will enable the normal tissue and whole body elemental composition of rainbow trout at any size to be determined. My results indicate that body burden or wet weight concentration are better indicators of elemental status than dry weight concentration and that comparison of elemental levels between treatment groups in dietary experiments should be made on the basis of a standard-sized fish or by comparing the rates of elemental deposition with growth.

Trophic Relationships of Fishes Occurring Within a Surf Zone Habitat in the Northern Gulf of Mexico

We studied trophic relationships of Florida pompano (Trachinotus carolinus), gulf kingfish (Menticirrhus littoralis), scaled sardine (Harengula jaguana), striped anchovy (Anchoa hepsetus) and dusky anchovy (A. lyolepis) during their spring residency in the Horn Island, Mississippi, surf zone. Harengula jaguana, A. lyolepis and A. hepsetus were zooplanktivores, utilizing primarily calanoid copepods, mysids and various decapod larvae. Menticirrhus littoralis and T. carolinus utilized benthic prey including Donax, Emerita and polychaetes; however, small pompano also fed on zooplankton. Menticirrhus littoralis, T. carolinus, H. jaguana and A. lyolepis also showed distinct dietary changes with increasing fish size. Three species, A. lyolepis, H. jaguana and M. littoralis fed at least partially at night, while T. carolinus and A. hepsetus were primarily diurnal predators. Cluster analysis of size intervals of all species based on presence or absence of prey taxa formed groups consistent with taxonomic relationships, thus indicating considerable interspecific resource separation.

Influence of certain environmental factors on the predatory efficiency of the larvivorous fishMacropodus cupanus

Investigations of the effect of certain environmental factors on predatory efficiency of the indigenous larvivorous fishMacropodus cupanus indicates the dependence, in a quantifiable way, of predation on the environmental complex surrounding the prey-predator system. Prey consumption is less at low temperatures and increases significantly with rise in temperature. Feeding under conditions of light is significantly higher than in darkness. Salinities of up to 21.83‰ do not affect predation rate, except that owing to stress conditions, prey intake at 21.83‰ is lower than at 0.12‰ Considering fish size, in terms of unit body weight, predation declines significantly as size increases. However, when total body weight is considered, predation increases with increase in fish size. Environmental factors do not alter the time course of predation regularly or significantly, perhaps owing to haphazard intake subsequent to satiation and/or a ‘learning’ factor. The higher predation rate of this fish when compared to the conventional larvivoreGambusia affinis indicates its potential as a biocontrol agent of mosquito larvae.

Toxicity of phenolic compounds in relation to the size of a freshwater fish, Notopterus notopterus (pallas)

Fish, Notopterus notopterus, in four sizes (4.5 ± 1.0, 9.0 ± 1.0, 14.5 ± 1.2, and 22.6 ± 1.8 cm in length) were exposed to phenol (P), 2,4-dinitrophenol (DNP), and pentachlorophenol (PCP) separately, and also to their three combinations (PCP + DNP) P (highly antagonistic), (DNP + P) PCP (additive), and (P + DNP) PCP (highly synergistic) to evaluate the effect of fish size on the toxicity of these chemicals separately and in combination. The results reveal that with increased fish size (from 4.5 + 1.0 to 14.5 + 12 cm in length) toxicity of phenolic compounds decreased. On the contrary, the larger size fish (22.6 ± 1.8 cm in length) was comparatively more susceptible. This indicates that change in fish size does influence the toxicity of phenolic compounds.

Effect of Growth Rate and Size of Fish on Rate of Intoxication by Waterfoorne Lead

Three experiments were undertaken to test the null hypotheses that increasing fish size and growth rate do not increase the rate of intoxication of fish by lead. The first experiment demonstrated that there were no significant correlations between weight of fish and either whole-body or blood lead concentrations in feral lake trout (Salvelinus namaycush). The whole-body lead concentration of rainbow smelt (Osmerus mordax) was, however, negatively correlated to wet weight.During the second experiment, an 8-d laboratory exposure of rainbow trout (Salmo gairdneri) to 100 μg/L of total waterborne lead caused a greater uptake of lead by opercular bone in small fish than in larger fish. No relationship was apparent between fish weight and uptake of lead by blood.Chronic exposure of juvenile rainbow trout to lead results in the development of black tails, a symptom of neurotoxicity. The final experiment related the incidence and prevalence of black tails to size and growth rate (ration level) of juvenile rainbow trout chronically exposed to 543 μg/L of total waterborne lead starting with the sac-fry stage. At weights below a common threshold size of 1.5–2.5 g, no black tails occurred; above this threshold the incidence of black tails was a function of growth rate, i.e. the rate at which fish reached the threshold size. The prevalence of black tails was always less in slowly growing fish.These experiments demonstrated that the rate of intoxication by lead, as indicated by uptake rates into tissues and the incidence and prevalence of a symptom of neurotoxicity, did not increase with fish size, but rather with growth rate.Key words: fish, toxicity, lead, fish size, growth rate, neurotoxicity, uptake