scholarly journals The trophic structure of fish in seaweed farms, and adjacent seagrass and coral habitats in Zanzibar, Tanzania

2021 ◽  
Vol 19 (2) ◽  
pp. 17-27
Author(s):  
Batuli M. Yahya ◽  
Saleh A. Yahya ◽  
Aviti J. Mmochi ◽  
Narriman S. Jiddawi
Keyword(s):  
Coral Reefs ◽  
Trophic Structure ◽  
Relative Proportion ◽  
Predatory Fish ◽  
Gut Contents ◽  
Fish Diet ◽  
Diet Specialization ◽  
Floating Seaweed ◽  
Significant Difference ◽  
Prey Items

Coral reefs, seagrasses and seaweed farms (Eucheuma denticulatum) are characteristic habitats in many parts of the coast of Zanzibar, Tanzania. However, information on trophic interactions, movements of fish, and variation in fish diet specialization between these habitats are scarce. The present study determined the trophic structure and the variation in diet composition of fish caught in (floating) seaweed farms, and in adjacent seagrass and coral reef habitats in Pongwe, Zanzibar. Fish were caught using traditional basket traps (dema) and gut contents of 392 fish were analyzed. A one-way Analysis of Similarities (ANOSIM) showed that there was a significant difference in the composition of prey items eaten by invertivores in different habitats (Global R = 0.109, p = 0.002.). There was no significant difference in the composition of prey items eaten by herbivores, invertivore-piscivores and omnivores (p > 0.05), likely due to movement of fish between these habitats for foraging. There was no significant difference in the relative proportion of trophic groups between the habitats (p > 0.05) except for herbivores (p < 0.05). Floating seaweed farms attract invertebrates and smaller fish, thus providing feeding grounds for predatory fish, and should be considered as ecologically important habitats as are coral reefs and seagrass beds.

scholarly journals Diet of Dinocras cephalotes and Perla marginata (Plecoptera: Perlidae) in an Apennine stream (northwestern Italy)

2007 ◽  
Vol 139 (3) ◽  
pp. 358-364 ◽  
Author(s):  
Tiziano Bo ◽  
Stefano Fenoglio ◽  
Giorgio Malacarne
Keyword(s):  
Trophic Structure ◽  
Prey Selection ◽  
Feeding Habits ◽  
Gut Contents ◽  
Freshwater Invertebrates ◽  
Trophic Preferences ◽  
Prey Items

AbstractThe feeding habits of nymphs of Perla marginata (Panzer) and Dinocras cephalotes (Curtis) were investigated in the Rio Orbarina (northwestern Italy). These species are among the largest European carnivorous freshwater invertebrates and they play an important role in the trophic structure of small, fishless Apennine streams. We examined the gut contents of 60 P. marginata and 60 D. cephalotes nymphs to characterize the diets and evaluate possible feeding differences between the species. In both of these predaceous stoneflies, the diet included vegetable detritus, mainly in the smaller instars. Both species showed trophic preferences, since only a few taxa constituted most of the ingested prey items, independently of their availability in the substratum. Interestingly, there were no clear differences in prey selection between nymphs of the two species.

scholarly journals Rainy Season Food Availability for Anurans of Kimboza Forest Reserve, Tanzania

2021 ◽  
pp. 15-25
Author(s):  
Nsajigwa Emmanuel Mbije ◽  
Asha Kamungu
Keyword(s):  
Food Availability ◽  
Rainy Season ◽  
Diet Composition ◽  
Feeding Habits ◽  
Gut Contents ◽  
Generalist Predators ◽  
Forest Reserve ◽  
Significant Difference ◽  
To Come ◽  
Prey Items

Amphibians are mostly considered to be generalist predators. Some species have a narrow diet or even specialize on certain prey categories. An assessment of the feeding habits of anuran species of Kimboza forest reserve, Tanzania was conducted during rainy season between March 2017 and June 2017. Through a visual encounter survey, 93 species were captured and analyzed for gut contents. About 462 prey items were identified the most abundant component being Isoptera and Hymenoptera. There was no significant difference (P > 0.05) in the anurans’ diet (composition or diversity or preferences) among different habitats of the forest (along boundaries and within the forest) but significant difference (P < 0.05) was found between the upper Stratum and the lower Stratum of the forest. The study provides a preliminary estimation of the actual diet of anurans and establishes a general feeding pattern for these species for the management of the Kimboza forest reserve. The study recommends the intensification of similar assessments in the nearby forest areas to come up with a complete description of the feeding habits for management purposes.

scholarly journals Diet Composition and Seasonal Fluctuations in the Feeding Habit of Snow Barbel (Schizothorax plagiostomus) in River Indus, Pakistan

2018 ◽  
Vol 46 (1) ◽  
pp. 8
Author(s):  
Muhammad Qayash Khan ◽  
Muhammad Zubair Anjum ◽  
Shamim Akhter ◽  
Irfan Khattak ◽  
Abid Ali
Keyword(s):  
Diet Composition ◽  
Feeding Activity ◽  
Fish Fauna ◽  
Feeding Habit ◽  
Gut Contents ◽  
Catch Per Unit Effort ◽  
Food Items ◽  
Unit Effort ◽  
Significant Difference ◽  
River Indus

Background:Schizothorax plagiostomus is widely distributed in river Indus and is most important food fish in Pakistan. The feeding habit of fish is directly related to the size of fish, its metabolic rate and environmental temperature. The accurate description of fish diet and feeding habit is a very important aspect in fisheries management for the purpose of species conservation, breeding and culture. The present work was aimed to investigate the specie abundance, the diet composition and seasonal variations in the feeding habit of Snow barbell Schizothorax plagiostomus.Materials, Methods & Results: A total of 1799 fish specimens were caught at the confluence of six tributaries along river Indus at Indus Kohistan, northeastern Pakistan. The fish were collected by 5-panels of gill net during first week of each month. The site specific Catch Per Unit Effort (CPUE) and season specific CPUE of fish fauna were assessed. For the gut content analysis 240 samples (99 male and 141 females) of S. plagiostomus were selected on monthly basis. Frequency of occurrence method and volumetric method were applied to record the different food items in the gut of S. plagiostomus. The physico-chemical parameters, NO3 concentration and dissolved Co2 of water from different localities of river Indus were recorded month wise by Hach sensION 156 meter, Horiba LAQUA Nitrate Meter and EA80 meter respectively. Significant difference was observed in water temperature during the four seasons. Except alkalinity no other water parameter showed significant variation across different localities. The results showed that highest Mean CPUE was observed for Darel Stream (0.55) and lowest for Jalkot stream (0.26). Peak abundance of fish was recorded in the month of November with a mean catch of 44.50, mean CPUE of 0.74 and mean Kruskal-Wallis rank value of 63.25. Spirogyra and Ulothrix occurred as maximum food items in the gut of S. plagiostomus during summer while their minimum amount occurred during autumn. According to the ranking index spirogyra and ulothrix ranked higher with significant difference in comparison to other food items. The results showed that S. plagiostomus is phytophagous in its feeding habit, which consumed mainly algae attached to stones and pebbles during the whole year. However, the presence of some secondary items such as animal matter, detritus, sand and mud might be due to the distinct availabilities of food along the seasons. The highest feeding activity of S. plagiostomus was recorded during summer while the lowest one occurred during autumn, spring and winter. Discussion: Catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. It is used as an index of stock abundance in fisheries and conservation biology. During the study low fish fauna was found in River Indus as reported previously. Majority of the fish occurred in snow fed river tributaries in the study area as these tributaries are comparatively less turbulent. Previous studies have also recorded that Schizothoracine generally prefer clean waters. The present findings of gut contents analysis showed clearly that S. plagiostomus is a phytophagous fish which scrap and consumed spirogyra and ulothrix attached to stones and pebbles. Earlier it was reported that mouth of S. plagiostomusis is inferior, wide, with deep lower jaw having keratinized cutting edge and the lower lip is folded and expanded with numerous papillae making it best suited for scrapping algae attached to stones and pebbles. The highest feeding activity was observed during warmer months as compared to cold months. S. plagiostomus spawn twice in a year in autumn and in spring. The highest feeding activity of S. plagiostomus seems to be link with a reflex of recovery strategy due to physiological process of gonadal development.

scholarly journals Utilization of fish waste as fish meal substitute in formulated fish diet on the growth performance of Nile tilapia fish fry (Oreochromis niloticus)

Food Research ◽  
2021 ◽  
Vol 5 (S4) ◽  
pp. 21-29
Author(s):  
Anizah M.R. ◽  
S.R. Manaf ◽  
Hilaliyah M.J.N.
Keyword(s):  
Growth Rate ◽  
Weight Gain ◽  
Specific Growth Rate ◽  
Protein Level ◽  
Nile Tilapia ◽  
Fish Meal ◽  
Specific Growth ◽  
Fish Diet ◽  
Fish Waste ◽  
Significant Difference

Fish meal is generally expended as the foremost protein supply in the fish diet. The rising cost of this component inflicted the aquaculture industry to seek a substitute in lessening the pellet cost. Thus, fish waste was tested in this study to investigate its viability. An experiment was performed to study the effects of fish waste and carcass on the growth performance of Nile tilapia fry. Solid fish waste of three different common species available in Mukah’s wet market was formulated into an artificial diet. The diet was formulated into three treatments consist of three protein levels (40%, 45% and 50%) with 4000 kcal/kg energy. A controlled group was fed with a commercial pellet consisting of 45% protein level. Fish were fed at 4% of body weight twice daily for 45 days. Fry reared in a controlled group was discovered highest weight gain, specific growth rate and length gain. There was no significant difference in all treatments for all parameters measured. The lowest weight gain and specific growth rate were recorded in fish fed 45% protein level (T2) group. Fish in T3 (50%) achieved the highest survival rate while T1 (40%) group recorded the lowest. The best and lowest Feed Conversion ratio (FCR) was recorded in the control group. In conclusion, the performance of formulated feed using fish waste is similar to commercial pellet as no significant difference can be observed in all parameters measured.

scholarly journals Low occurrence rates of ubiquitously present leptocephalus larvae in the stomach contents of predatory fish

2015 ◽  
Vol 72 (5) ◽  
pp. 1359-1369 ◽  
Author(s):  
Michael J. Miller ◽  
Jeff Dubosc ◽  
Elodie Vourey ◽  
Katsumi Tsukamoto ◽  
Valerie Allain
Keyword(s):  
Stomach Contents ◽  
Trophic Dynamics ◽  
Predatory Fish ◽  
Thunnus Albacares ◽  
Fish Diets ◽  
Thunnus Obesus ◽  
Leptocephalus Larvae ◽  
Subtropical Oceans ◽  
Oceanic Food Webs ◽  
Prey Items

Abstract Leptocephali, the larvae of eels, grow to large sizes and are widely distributed in tropical and subtropical oceans. Their role in oceanic food webs is poorly known because they are rarely reported as food items in fish stomach content studies. Data from 13 years of research on the trophic dynamics of Pacific Ocean predatory fish indicate that among 8746 fish of 76 species/taxa (33 families) that had been feeding, only 16 fish of 6 species had remains of 34 leptocephali in their stomachs. Only 0.013% of the 256 308 total prey items were leptocephalus larvae, and 0.03% of the total prey items were juvenile or adult eels (mostly snipe eels: Nemichthyidae). There were 10 fish of 2 species of lancetfish (Alepisaurus spp., n = 152), 2 rainbow runners (Elagatis bipinnulata, n = 222), and 2 yellowfin tuna (Thunnus albacares, n = 3103) that had leptocephali in their stomach contents, but all except one T. albacares (contained 15 leptocephali) had each eaten ≤3 leptocephali. A swallower, Pseudoscopelus sp., and a frigate tuna, Auxis thazard, had eaten single leptocephali. Twenty-eight bigeye tuna, Thunnus obesus, had eaten 76 juvenile/adult nemichthyid or serrivomerid eels. A literature survey found that only 15 out of 75 examined publications listed leptocephali in the stomach contents of a total of 6 species out of ∼ 42 300 predatory fish of 40 species. The transparency of leptocephali and their apparent mimicry of gelatinous zooplankton could contribute to lower rates of predation. Their soft bodies likely digest rapidly, so although this study and existing literature indicate that leptocephali sometimes contribute to predatory fish diets, particularly for fish that do not exclude gelatinous prey types, and fish with low digestion rates in their stomachs such as lancetfish, their levels of contribution to fish diets and the impacts of predators on eel recruitment remain uncertain.

Coral Reefs: A Very Short Introduction

2021 ◽  
Author(s):  
Charles Sheppard
Keyword(s):  
Coral Reefs ◽  
Predatory Fish ◽  
Ocean Water ◽  
Coral Reef Ecosystem ◽  
Short Introduction ◽  
Coral Colony ◽  
Coral Polyp ◽  
Local Impacts ◽  
Microbial Systems ◽  
Do So

Reefs and the coral life that builds them were for centuries a source of mystery to naturalists and hazard to seafarers. Many ideas were developed of what built them and why they all existed so close to sea level but never above it. Darwin developed the theory of how they were built, which was proven a century later. The coral polyp is central to each coral colony and to the reef. Each houses countless symbiotic algal cells that provide the energy that supports the coral reef ecosystem, and the energy needed to extract minerals from seawater to deposit as solid limestone. These are the ocean’s most biodiverse ecosystem. The islands perched on them include many entire nations, and reefs provide land, food, and protection to these as well as parts of many others. The diversity and abundance of other species, from microbial systems that are key to nutrient and energy transfer, to the large predatory fish, are similarly vast, and various components of the reef system have been researched intensively since the advent of scuba techniques. Today, however, local impacts and pressures from pollution to overfishing have degraded and damaged many, and more recently, warming of ocean water resulting from climate change is causing an existential threat to the survival of this rich ecosystem. Arresting the decline is no longer a scientific problem but one for society and governments, and failure to do so will result, indeed already is, in untold damage to human societies that depend on coral reefs.

Wabash River Freshwater Drum Aplodinotus grunniens Diet: Effects of Body Size, Sex, and River Gradient

2013 ◽  
Vol 5 (1) ◽  
pp. 133-140 ◽  
Author(s):  
Stephen J. Jacquemin ◽  
Mark Pyron ◽  
Michael Allen ◽  
Lucas Etchison
Keyword(s):  
Body Size ◽  
Generalized Linear Model ◽  
Longitudinal Gradient ◽  
Diet Diversity ◽  
Diet Specialization ◽  
Wabash River ◽  
Aplodinotus Grunniens ◽  
Caddisfly Larvae ◽  
Freshwater Drum ◽  
Prey Items

Abstract The objectives of this study were to describe the diets of freshwater drum Aplodinotus grunniens in the Wabash River in the Midwestern United States. We used a multivariate ordination approach (nonmetric multidimensional scaling) to describe drum diets combined with a generalized linear model to test for covariation of diet with body size, sex, and longitudinal river gradient. Hydropsychidae (trichoptera, caddisfly larvae), pleuroceridae (gastropoda), and heptageniidae (ephemeroptera, mayfly larvae) were the most consumed prey items (∼75% of overall diets). Among all freshwater drum, hydropsychidae, pleuroceridae, and heptageniidae were present in 69%, 23%, and 38% of stomachs, respectively. Freshwater drum diets were similar along an upstream–downstream river gradient spanning 350 river km, but varied with body size and sex. Small- and medium-sized fish tended to consume more diptera and annelids compared with the largest individuals, which fed on mollusks and crayfish. With control for body size, the diets of male individuals were composed of more diptera (chironomidae) and annelid prey items compared with female individuals, whose diets included more molluscs and crayfish. Overall, we interpret the lack of diet diversity in freshwater drum with Wabash River longitudinal gradient as evidence of diet specialization. Alternatively, we propose that a potential dietary–river-gradient signal may be diluted as a function of increased freshwater drum longitudinal movements.

The Diet of the Nestling Noisy Scrub-Bird, Atrichornis Clamosus.

1984 ◽  
Vol 11 (3) ◽  
pp. 553 ◽  
Author(s):  
GT Smith ◽  
MC Calver
Keyword(s):  
Generalist Predator ◽  
Main Prey ◽  
Significant Difference ◽  
Different Ages ◽  
Prey Items ◽  
Combined Data

The diet of nestling noisy scrub-birds, Atrichornis clamosus, was determined from observations at 12 nests and from examination of 718 faecal sacs. Nestlings were fed invertebrates of 18 orders plus a few small vertebrates. There was no significant difference in the proportions of the various taxa as determined from observational and faecal sac data. The most common prey from the combined data were Araneida (35%), Orthoptera (29%), larvae (13%), Blattodea (7%), Hymenoptera (4%), Chilopoda (3%), and Lumbricidae (2%). There were significant differences between the proportions of the main prey items between years, within years and within territories. There were no significant differences in the type of prey fed at different ages. The data suggest that the female noisy scrub-bird is a generalist predator when feeding her young.

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