SPLITTING OF TROPHIC NICHES IN UNDERYEARLINGS OF MINNOW PHOXINUS PHOXINUS (L.) AND GUDGEON GOBIO GOBIO (L.) SHARING THE SAME HABITAT

The article gives the results of determining feeding spectra of underyearlings of minnow ( Phoxinus phoxinus (L.)) and gudgeon ( Gobio gobio (L.)) living in the middle flow of the river Kes’ma (tributary of Rybinsk reservoir), as well as limits of feeding biotopes of their juveniles and proportion of structural zones determining their ecological niches at the first year of life. Analysis of similarity and distinction of food composition consumed by fry of both fish species utilizing common foraging resources in the process of sharing the same habitat was performed. It was shown that diet of gudgeon fry is more diverse, compared to minnow fry. Gudgeon was found to forage on invertebrates belonging to seven classes while minnow’s diet comprised representatives of four classes. Food objects common for both fish species were oligochaetes and larvae of amphibiotic insects. Chironomid larvae dominated in the food of both fish species. This can be observed in both the frequency of occurrence of these food items in the digestive tract (100%), as well as in the indices of its mass in the boluses. Species composition of chironomid larvae found in the food of gudgeon and minnow was significantly different. These differences are conditioned by both the biological features of single species such as their confinement to certain micro-habitats as well as the foraging behavior of fish fry. Because of current lack of hydrobiological research in the Kes’ma river, the prelist of invertebrates found in dietary intake of fish fry of the local habitat is considered to have a great practical value.

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The biology of Acanthoclinus quadridactylus (Bloch and Schneider) (Teleostei-Blennioidea). I. Age, growth, and food

Marine and Freshwater Research ◽

10.1071/mf9680001 ◽

1968 ◽

Vol 19 (1) ◽

pp. 1 ◽

Cited By ~ 7

Author(s):

JB Jillett

Keyword(s):

Growth Rate ◽

Single Species ◽

Age And Growth ◽

Gut Contents ◽

First Year ◽

Selective Feeding ◽

Important Food ◽

Growth Zones ◽

First Year Of Life

Age, growth, and food of a population of Acanthoclinus quadridactylus were studied from December 1959 to December 1960. Age and growth were investigated by means of length frequencies of fish and by the analysis of growth zones shown in their sagittal otoliths. The growth rate decreases with age and growth is retarded during winter months. Fish live to a maximum age of at least nine years at which time they are approximately 20 cm long. There are no marked differences in growth or longevity between the sexes. Analysis of gut contents showed that A. quadridactylus is an omnivorous carnivore. Diet is apparently restricted by availability rather than by selective feeding. Decapods were the most important food organisms and Petrolisthes elongatus was the most important single species. Other food organisms included (in order of importance) isopods, barnacles, amphipods, chitons, gastropods, bivalves, polychaetes, fish, and bryozoans. There is evidence of a change of diet in the first year of life.

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The Development of Swallowing Respiratory Coordination

Perspectives on Swallowing and Swallowing Disorders (Dysphagia) ◽

10.1044/sasd18.1.19 ◽

2009 ◽

Vol 18 (1) ◽

pp. 19-24

Author(s):

Maggie-Lee Huckabee

Keyword(s):

Cortical Activation ◽

First Year ◽

Healthy Children ◽

Nasal Airflow ◽

Single Session ◽

Primary Finding ◽

Patterns Of Behavior ◽

Cortical Modulation ◽

First Year Of Life ◽

Swallowing Apnea

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.

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