Trophic shifts in three subtropical Australian halfbeaks (Teleostei:Hemiramphidae)

To elucidate the trophic status of hemiramphids, the diets of three species from subtropical south-east Queensland were investigated. All undergo a marked ontogenetic trophic shift from an animal to plant diet, which occurred between 50 and 70 mm standard length (Ls) for Arrhamphus sclerolepis krefftii (freshwater) and between 80 and 110 mm Ls for both Hyporhamphus regularis ardelio and H. quoyi (both marine). After the ontogenetic shift, the diet of A. sclerolepis krefftii is dominated by filamentous algae, whereas the diet of the two marine species is dominated by Zostera capricorni. The two marine species feed mainly during the day, with gut fullness dropping markedly after dusk. Neither showed evidence of a diel trophic shift between herbivory and carnivory that has been reported for other hemiramphids. The lack of diel trophic switching in these subtropical hemiramphids may suggest that latitudinal effects on daylength and/or water temperature may influence the extent to which hemiramphids switch periodically to animal prey from an otherwise essentially herbivorous diet in order to balance their nutrient requirements.

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Development of the pharyngeal dentition of two herbivorous halfbeaks (Teleostei : Hemiramphidae) and implications for the hemiramphid ontogenetic trophic shift

Marine and Freshwater Research ◽

10.1071/mf07026 ◽

2008 ◽

Vol 59 (2) ◽

pp. 117 ◽

Cited By ~ 4

Author(s):

Ian R. Tibbetts ◽

Ryan D. Day ◽

Lee Carseldine

Keyword(s):

Standard Length ◽

Plant Material ◽

Tooth Wear ◽

Pharyngeal Tooth ◽

Wear Area ◽

Ecological Implications ◽

Trophic Shift ◽

Tooth Number ◽

Almost All

Development of the pharyngeal dentition of two herbivorous halfbeaks, Hyporhamphus regularis ardelio (Whitley, 1931) and Arrhamphus sclerolepis krefftii (Steindachner, 1867), was examined quantitatively to assess features that might confer their ability to shift their diet from animal to plant material. Toothed area, tooth number, maximum tooth diameter and tooth wear area in both pharyngeal tooth pads of both taxa increased with ontogeny, whereas tooth density decreased. Comparing individuals of the two taxa at similar standard lengths indicated that A. sclerolepis krefftii showed hypertrophy of the majority of pharyngeal characters in relation to H. regularis ardelio of a similar standard length. That A. sclerolepis krefftii is more developmentally advanced than H. regularis ardelio in almost all dentigerous characters studied indicates that pharyngeal development may allow the former to commence herbivory at a smaller standard length than the latter species. The evolutionary and ecological implications of these findings are discussed in the context of a group of fishes that is overexploited worldwide.

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Foraging behaviour of Atlantic cod (Gadus morhua) larvae in relation to prey concentration

Canadian Journal of Zoology ◽

10.1139/z02-045 ◽

2002 ◽

Vol 80 (4) ◽

pp. 689-699 ◽

Cited By ~ 22

Author(s):

V Puvanendran ◽

L L Leader ◽

J A Brown

Keyword(s):

Standard Length ◽

Gadus Morhua ◽

Foraging Behaviour ◽

Atlantic Cod ◽

Extended Period ◽

Prey Concentration ◽

Intensive Rearing ◽

Gut Fullness ◽

Atlantic Cod Larvae ◽

Tremendous Amount

In spite of a tremendous amount of research on Atlantic cod (Gadus morhua) larvae, no information is available on the development of foraging behaviour over an extended period. We investigated the ontogeny of foraging behaviour of Atlantic cod larvae exposed to different prey concentrations from hatching to metamorphosis. The objective of this work was to determine if their foraging behaviour is influenced by prey concentration. Rotifers and (or) Artemia sp. were used as prey at concentrations of 0, 500, 1000, 2000, and 4000/L. During behavioural observations, which were carried out twice a week, foraging behaviour and activity of cod larvae were quantified. Larvae were sampled once a week and standard length and gut fullness were recorded. Larvae reared at concentrations of 1000 and 2000 prey/L swam significantly more but foraged (quantified by capture success) significantly less than the larvae reared at 4000 prey/L. Larvae reared at 4000 prey/L performed more orientations towards prey than larvae reared at all lower prey concentrations and the time spent per orientation increased from day 2 at all prey concentrations but declined as the larvae grew. However, this decline occurred earlier in larvae reared at 4000 prey/L than in larvae reared at other prey concentrations, and larvae reared at 4000 prey/L spent the shortest time per orientation at day 27 compared with day 34. Larvae reared at 4000 prey/L showed significantly higher success in capturing prey than larvae reared at all lower prey concentrations. After day 13 post hatch, larvae reared at 4000 prey/L were significantly greater in length than larvae reared at all other prey concentrations. Larvae reared at 0, 500, and 1000 prey/L did not survive beyond 11, 15, and 32 days, respectively, indicating that fewer than 2000 prey/L may not be adequate to keep cod larvae alive during intensive rearing. Our results suggest that the foraging behaviour of Atlantic cod larvae is influenced by prey concentration.

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EURRECAs Approach for Estimating Micronutrient Requirements

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000071 ◽

2011 ◽

Vol 81 (4) ◽

pp. 256-263 ◽

Cited By ~ 22

Author(s):

Christophe Matthys ◽

Pieter van ‘t Veer ◽

Lisette de Groot ◽

Lee Hooper ◽

Adriënne E.J.M. Cavelaars ◽

...

Keyword(s):

Reference Values ◽

Policy Decision ◽

Individual Variability ◽

The Body ◽

Decision Makers ◽

Nutrient Requirements ◽

Factorial Approach ◽

Dietary Reference Values ◽

Health Policy Decision ◽

Quantitative Integration

In Europe, micronutrient dietary reference values have been established by (inter)national committees of experts and are used by public health policy decision-makers to monitor and assess the adequacy of diets within population groups. The approaches used to derive dietary reference values (including average requirements) vary considerably across countries, and so far no evidence-based reason has been identified for this variation. Nutrient requirements are traditionally based on the minimum amount of a nutrient needed by an individual to avoid deficiency, and is defined by the bodys physiological needs. Alternatively the requirement can be defined as the intake at which health is optimal, including the prevention of chronic diet-related diseases. Both approaches are confronted with many challenges (e. g., bioavailability, inter and intra-individual variability). EURRECA has derived a transparent approach for the quantitative integration of evidence on Intake-Status-Health associations and/or Factorial approach (including bioavailability) estimates. To facilitate the derivation of dietary reference values, EURopean micronutrient RECommendations Aligned (EURRECA) is developing a process flow chart to guide nutrient requirement-setting bodies through the process of setting dietary reference values, which aims to facilitate the scientific alignment of deriving these values.

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High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

Marine Ecology Progress Series ◽

10.3354/meps13251 ◽

2020 ◽

Vol 637 ◽

pp. 195-208 ◽

Cited By ~ 1

Author(s):

EM DeRoy ◽

R Scott ◽

NE Hussey ◽

HJ MacIsaac

Keyword(s):

Invasive Species ◽

Native Species ◽

Ecological Impact ◽

Marine Species ◽

Ecological Impacts ◽

Negative Effects ◽

Marine Predator ◽

Eastern Gulf Of Mexico ◽

Red Grouper ◽

Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

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The Economics of Protected Marine Species: Concepts in Research and Management

10.3389/978-2-88919-990-7 ◽

2016 ◽

Keyword(s):

Marine Species ◽

Species Concepts

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Reply to J. G. M. Thewissen's Review of the Book Morphology of the Auditory and Vestibular Organs in Mammals, with Emphasis on Marine Species

Aquatic Mammals ◽

10.1578/am.34.1.2008.145 ◽

2008 ◽

Vol 34 (1) ◽

pp. 145-146

Author(s):

Galina N. Solntseva

Keyword(s):

Marine Species ◽

Vestibular Organs

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Removal of nutrients from Organic Liquid Agricultural Waste using filamentous algae.

Brazilian Journal of Biology ◽

10.1590/1519-6984.224708 ◽

2020 ◽

Author(s):

Gonzalo Flores-Morales ◽

Mónica Díaz ◽

Patricia Arancibia-Avila ◽

Michelle Muñoz-Carrasco ◽

Pamela Jara-Zapata ◽

...

Keyword(s):

Organic Waste ◽

Low Cost ◽

Organic Liquid ◽

Agricultural Waste ◽

Filamentous Algae ◽

Tertiary Treatment ◽

Nutrient Reduction ◽

Algae Removal ◽

Algae Growth ◽

Waste Effluents

Abstract A feasibility analysis of tertiary treatment for Organic Liquid Agricultural Waste is presented using filamentous algae belonging to the genus Cladophora sp. as an alternative to chemical tertiary treatment. The main advantages of tertiary treatments that use biological systems are the low cost investment and the minimal dependence on environmental variables. In this work we demonstrate that filamentous algae reduces the nutrient load of nitrate (circa 75%) and phosphate (circa 86%) from the organic waste effluents coming from dairy farms after nine days of culture, with the added advantage being that after the treatment period, algae removal can be achieved by simple procedures. Currently, the organic wastewater is discarded into fields and local streams. However, the algae can acquire value as a by-product since it has various uses as compost, cellulose, and biogas. A disadvantage of this system is that clean water must be used to achieve enough water transparency to allow algae growth. Even so, the nutrient reduction system of the organic effluents proposed is friendly to the ecosystem, compared to tertiary treatments that use chemicals to precipitate and collect nutrients such as nitrates and phosphates.

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