scholarly journals Distribution of α amylase along the alimentary tract of two Mediterranean fish species, the parrotfish Sparisoma cretense L. and the stargazer, Uranoscopus scaber L

2003 ◽  
Vol 4 (2) ◽  
pp. 115 ◽  
Author(s):  
E.S. PAPOUTSOGLOU ◽  
A.R. LYNDON

There is very little information available for the only Mediterranean species of parrotfish ( Sparisoma cretense) and its feeding habits, especially since most other parrotfish species are associated with coral reefs. The same lack of information is true for another fish species, the stargazer ( Uranoscopus scaber), which is carnivorous, and important for local fisheries in the Mediterranean. Comparative information is presented concerning the digestive activity and capacity for alpha amylase for these species with completely different feeding strategies, as well as main location(s) of carbohydrate digestion along their digestive tract. Alphaamylase activity and capacity is significantly higher in S. cretensethan U. scaber(p<0.05). Activity in S. cretense is very high, comparable to levels reported for carp and tilapia. It is similar in anterior and posterior intestine, however, the posterior intestine comprises a more important role in alpha amylase capacity. In U. scaber, activity is present in pyloric caeca and intestine. Levels are very low, comparable to levels reported for other benthic marine carnivores. There is no difference between activities in intestine and pyloric caeca. However, activity is higher in the anterior part of the intestine, lower in the posterior intestine and absent in the stomach. Such information is thought to be beneficial for improving knowledge on the biology of the examined species, and the physiology of nutrition, as well as for assisting towards understanding these processes in other, more valuable species for aquaculture. Also, the possibility of using the stargazer alimentary tract, especially its pyloric caeca as a model system is discussed.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Bhaskara Canan ◽  
Wallace Silva do Nascimento ◽  
Naisandra Bezerra da Silva ◽  
Sathyabama Chellappa

This study investigated the morphohistology of the digestive tract and the mean intestinal coefficient of the damsel fishStegastes fuscuscaptured from the tidal pools of Northeastern Brazil. The wall of the digestive tract ofS. fuscusis composed of the tunica mucosa, tunica muscularis, and tunica serosa. The esophagus is short with sphincter and thick distensible wall with longitudinally folded mucosa. Mucous glands are predominant, and the muscular layer of the esophagus presented striated fibers all along its extension. The transition region close to the stomach shows plain and striated muscular fibers. Between the stomach and intestine, there are three pyloric caeca. The intestine is long and thin with four folds around the stomach. The anterior intestine presents folds similar to those of pyloric caeca. The estimated mean intestinal coefficient and characteristics of the digestive system ofS. fuscuspresent morphological adequacy for both herbivorous and omnivorous feeding habits.


2019 ◽  
Vol 66 (3) ◽  
Author(s):  
Angela Maria Jaramillo-Londono ◽  
Alejandra Vanina Volpedo ◽  
Jose Luis Diaz-Arevalo ◽  
Maria Eugenia Rodrigo-Santamalia ◽  
Vicent Bendito-Dura

This work provides data on the somatic growth and age of selected commercial fish species of the Cullera Coast, Spain. The biological information available that permits responsible fishing management of these species is relatively scarce. This study was conducted in the Bay of Cullera, Spain (39º 12’to 38º 59’N, and 0º 09’to 0º 15’W); and selected benthic fish species were analysed that are frequently fished by trammel nets (mesh size 28-76 mm) at a maximum depth of 30 m. Maturity , age and growth of 63 torpedoes, Torpedo torpedo (L., 1758), 115 red scorpionfish, Scorpaena scrofa Linnaeus, 1758, 280 red mullets, Mullus surmuletus Linnaeus, 1758, 139 stargazers, Uranoscopus scaber Linnaeus, 1758, and 476 Portuguese soles, Dagetichthys lusitanicus de Brito Capello, 1868 were analysed. The data obtained in this study revealed that 50% of individuals of all the species reached sexual maturity at a TL (total length) of 20.0-36.5 cm and at an age of 2-6 years. The von Bertalanffy growth equation derived were: TL=37.0 (1 - e(-0.2(t + 0.33))); TL =31.5(1 - e(-0.38(t + 0.54))); TL =35.5(1 - e(-0.2(t + 2.08))); and TL =34.3(1 - e(-0.14(t + 2.16))) for S. scrofa, M. surmuletus; U. scaber and D. lusitanicus respectively.


2020 ◽  
Vol 32 (6) ◽  
pp. 496-507
Author(s):  
Loïc N. Michel ◽  
Fabienne L. Nyssen ◽  
Patrick Dauby ◽  
Marie Verheye

AbstractIn Antarctica, amphipods form a highly diverse group, occupy many different ecological niches and hold an important place in food webs. Here, we aimed to test whether differences in Antarctic amphipod feeding habits were reflected in their mandible morphology, and if mouthpart specialization could be used to describe amphipod trophic ecology. To do so, we compared mandible morphology in nine species spanning seven families and five functional groups (grazers, suspension feeders, generalist predators, specialist predators and scavengers). Mandible morphology adequately depicted some aspects of amphipod trophic ecology, such as the trophic level at which animals feed or their degree of dietary specialization. On the other hand, links between mandible morphology and amphipod diet were seldom unambiguous or straightforward. Similar adaptations were found in distinct functional groups. Conversely, mandible morphology could vary within a single functional group, and phylogenetic effects sometimes complicated the interpretation of form-function relationships. Overall, mandible morphology on its own was generally not sufficient to precisely predict amphipod feeding strategies. However, when combined with other methods (e.g. gut contents, trophic markers), it constitutes a valuable source of information for integrative studies of amphipod ecological diversity in the Southern Ocean.


2014 ◽  
Vol 71 (5) ◽  
pp. 1073-1087 ◽  
Author(s):  
T. Chouvelon ◽  
F. Caurant ◽  
Y. Cherel ◽  
B. Simon-Bouhet ◽  
J. Spitz ◽  
...  

Abstract Recent European environmental policies argue for the development of indicators of the ecological status of ecosystems that are easy to implement and powerful enough to detect changes quickly. For instance, some indicators that are currently proposed for monitoring foodweb structure and functioning are based on the size of organisms, using size as a proxy for trophic level. However, these indicators do not necessarily accurately reflect the underlying trophic structure and dynamics to follow. Ecological tracers (i.e. chemical parameters measured in consumer tissues to infer the trophic ecology of organisms) may serve as complementary indicators of trophic level, and may also help distinguish different populations of a species when more commonly used methods (e.g. genetic, age determination) present their own limitations. Here, we analysed the potential of muscle δ13C and δ15N values and of muscle mercury (Hg) concentrations to depict size-related trophic habits of different fish species. We expected that intra- and interspecific variation in these ecological tracers could be helpful in refining currently proposed indicators of marine ecosystems, and also help in discriminating management unitsfor some species. Four fish species were selected for their economical and/or ecological importance in the Bay of Biscay (Northeast Atlantic): whiting Merlangius merlangus, European hake Merluccius merluccius, Atlantic horse mackerel Trachurus trachurus and anglerfish Lophius piscatorius. Muscle δ13C and δ15N values segregated the species and enabled us to discriminate species-specific feeding strategies with increasing size of individuals. Fish body size was not always linearly correlated with δ15N or trophic level. In contrast, Hg concentrations and size-related Hg patterns were more similar from species to species. Interestingly, muscle δ15N values together with Hg concentrations segregated the two putative stocks of European hake within the Bay of Biscay. Hence, we propose the combined use of ecological tracers as a promising method for accurately assigning a consumer to a trophic guild, investigating Hg trophodynamics in foodwebs, and helping discriminate distinct ecological populations within a species when defining management units.


1988 ◽  
Vol 39 (3) ◽  
pp. 307 ◽  
Author(s):  
RK Howard

Nearshore limestone reefs of Western Australia represent an important nursery habitat for juveniles of the western rock lobster (Panulirus cygnus). As part of a trophic study of the fish community associated with these reefs, fishes were examined for evidence of predation on western rock lobsters. Six fish species were found to have ingested P. cygnus. Of these, Psammaperca waigiensis (sand bass), Pelsartia humeralis (sea trumpeter), Pseudolabris parilis (brown-spotted wrasse) and Plectorhyncus flavornaculatus (gold-spotted sweetlips) were among the ten most abundant fish in gill-net collections from the study site. P. cygnus formed a significant portion of the diet of P. waigiensis, but was < 5% of the dietary volume of other species. Predation occurred at all times of the day and was concentrated on small, newly-settled P. cygnus (8-15 mm carapace length). The vulnerability of lobsters to predation appears to be strongly related to size, and the cryptic habits that are unique to newly-settled stages can be explained in terms of the risks of predation. Assessment of the proportion of mortality of P. cygnus due to predation is hampered by a current lack of information on the natural densities of both fishes and small rock lobsters. However, conservative estimates indicate that an annual removal by fish of thousands of lobsters per hectare is likely, suggesting that predation is a major factor affecting the survival of P. cygnus on nursery reefs.


2013 ◽  
Vol 88 (3) ◽  
pp. 371-375 ◽  
Author(s):  
J. Navarro ◽  
M. Albo-Puigserver ◽  
M. Coll ◽  
R. Saez ◽  
M.G. Forero ◽  
...  

AbstractDuring the past decade, parasites have been considered important components of their ecosystems since they can modify food-web structures and functioning. One constraint to the inclusion of parasites in food-web models is the scarcity of available information on their feeding habits and host–parasite relationships. The stable isotope approach is suggested as a useful methodology to determine the trophic position and feeding habits of parasites. However, the isotopic approach is limited by the lack of information on the isotopic discrimination (ID) values of parasites, which is pivotal to avoiding the biased interpretation of isotopic results. In the present study we aimed to provide the first ID values of δ15N and δ13C between the gyrocotylidean tapeworm Gyrocotyle urna and its definitive host, the holocephalan Chimaera monstrosa. We also test the effect of host body size (body length and body mass) and sex of the host on the ID values. Finally, we illustrate how the trophic relationships of the fish host C. monstrosa and the tapeworm G. urna could vary relative to ID values. Similar to other studies with parasites, the ID values of the parasite–host system were negative for both isotopic values of N (Δδ15N = − 3.33 ± 0.63‰) and C (Δδ13C = − 1.32 ± 0.65‰), independent of the sex and size of the host. By comparing the specific ID obtained here with ID from other studies, we illustrate the importance of using specific ID in parasite–host systems to avoid potential errors in the interpretation of the results when surrogate values from similar systems or organisms are used.


1968 ◽  
Vol 25 (12) ◽  
pp. 2561-2574 ◽  
Author(s):  
John E. Fitch ◽  
Robert L. Brownell Jr.

The stomachs of 17 cetaceans of seven species (3 Kogia simus, 5 Stenella longirostris, 3 S. graffmani, 2 Lagenorhynchus obliquidens, 2 Delphinus delphis, 1 Lissodelphis borealis, and 1 Phocoena sinus) yielded 18,164 fish otoliths representing over 51 species, 40 genera, and 22 families. Lanternfish (family Myctophidae) otoliths accounted for more than 89% of the total, and they had come from at least 19 species belonging to nine genera. Only two fish species could have been identified if we had not been able to utilize otoliths. To be useful in food studies involving otoliths, cetacean stomachs cannot be placed in formalin solutions, even for short periods.The kinds and diversity of species preyed upon by several of these cetaceans indicate that they routinely forage in depths of 650–800 ft (200–250 m), and a few such as Kogia simus may descend to 1000 ft (300 m) or deeper.


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