Lunar influence on prey availability,diet shifts and niche overlap between Engraulidae larvae in tropical mangrove creeks

The influence of the lunar cycle on prey availability, diet shifts and overlap between larval Anchovia clupeoides and Cetengraulis edentulus was evaluated in mangrove creeks of the Goiana Estuary. Copepod eggs were highly abundant in the first and last quarter, at the full moon and zoea of Ucides cordatus (Ocypodidae) in the new moon. The Engraulidae larvae fed on microcrustaceans, algae and early planktonic stages of benthic organisms. The relative importance of prey varied according to prey availability in all moon phases. Larval diets were more even in the full and new moons, when the relative importance of calanoid copepods and zoeae of U. cordatus as food items increased (index of relative importance, >80% I_RI). Mangrove creeks were very important feeding grounds for engraulid larvae during spring tides. Larval diets were more diverse in the first and last‐quarter moon and included protozoeae of Caridean shrimp, larvae of Anomalocardia brasiliana (Veneridae), Isopoda, Gastropoda, ephippium of Daphnia sp. and nauplii of Cirripedia, Harpacticoidia and cyclopoid Copepoda. The last five items were not found in the creeks, suggesting feeding in the main channel. During neap tides, mangrove creeks were probably also used as refugia. These larvae are opportunistic and feed on highly available prey and both species feed on the same items, leading to high dietary overlap in all moon phases. The lunar cycle, which is related to the spring‐neap tidal cycle, was the major driver of quantitative and qualitative changes in feeding of engraulid larvae on a short time scale.     

Spring-neap cycle as a major driver of temporal variations in feeding of intertidal fishes: Evidence from the sea catfish Sciades herzbergii (Ariidae) of equatorial west Atlantic mangrove creeks

On macrotidal coasts, short- to medium term variations in feeding of intertidal fishes are influenced by several interacting time scales. To identify the driver of major variations in the feeding habits of intertidal fish, we used the pemecou sea catfish Sciades herzbergii (Ariidae), an abundant intertidal benthic second order consumer, as a model species. We analyzed the influence of the spring-neap and the day-night cycle on intertidal abundance, stomach fullness, diet composition and food consumption of S. herzbergii using block nets set at slack high tides in two mangrove creeks in north Brazil. At spring tides, intertidal abundance, stomach fullness, and total daily consumption of S. herzbergii were on average 8.8, 1.9, and 3.8 times higher than at neap tides, respectively. At spring tides, Uca spp. and Grapsidae (mostly Pachygrapsus gracilis) dominated the diet, irrespective of the time of day. Other important food items were Insecta and the semiterrestrial crab Ucides cordatus. At neap tides, Capitellidae contributed to the diet of nightly inundations while no specimens were caught at daytime. Creek location had no effect on any variable. Results from our study area and evidence from other studies suggest that the spring-neap tide pulse is likely the major driver of short- to medium term variations in feeding of intertidal fishes. This has important implications for feeding-related issues on macro- and probably also on mesotidal coasts: (i) juvenile fishes may have fortnightly growth spurts, (ii) intertidal prey populations may suffer regular fluctuations in mortality, (iii) studies of the feeding ecology of intertidal fishes should cover the combined effects of the tidal, diel, lunar and seasonal cycles, and (iv) the modeling of food webs should consider the differences between highly dynamic spring tide and quieter neap tide conditions.     

Tidal migration and patterns in feeding of the four-eyed fish Anableps anableps L. in a north Brazilian mangrove

The tidal migration, temporal and spatial patterns in feeding of the surface-swimming four-eyed fish Anableps anableps (Anablepidae) were studied in a macrotidal mangrove area in north Brazil to exemplify the ecology of a tropical intertidal fish. Visual censuses in the main channel showed that abundances were high at low water (LW) and low at high water (HW). Anableps anableps entered the intertidal creeks with the first flood rise. They fed in the inundated mangrove at HW and returned gradually after the ebb current maximum to concentrate again in the subtidal parts of the main channel at LW. This pattern occurred at neap, mid and spring tides throughout the year. The tidal migration was triggered by water level, not by time. In the study area the diet of A. anableps caught with block nets was dominated by intertidal red algae ( Catanella sp.). Other important food items were Insecta and Grapsidae. The combination of high inundation and daylight (spring tide-day) provided the best foraging conditions, probably emphasizing the importance of the above-water eye. Darkness and low inundation was linked to poorest foraging conditions (neap tide-night). The quantity of food consumed by A. anableps was clearly influenced by the factors tide, time of day and creek location, but not by size and sex. The qualitative composition of the diet was not influenced by any of the factors, except for mud, which was only ingested at neap tides. The temporal and spatial variability in food consumption suggests that food web modelling in macrotidal areas may lead to misinterpretations of the overall systems dynamics if the spring and neap tide alternation and the diurnal cycle are not considered.     

Contribution to the feeding ecology of the banded puffer fish Colomesus psittacus (Tetraodontidae) in north Brazilian mangrove creeks.

Stomach contents were examined from 102 banded puffer, Colomesus psittacus (Tetraodontidae), caught from intertidal mangrove creeks at diurnal neap tides between June and September, 1997 (early dry season) near Bragan?a (north Brazil). The study found that C. psittacus were specialized predators of Cirripedia (Balanus spp.) and Brachyuran crabs (Uca spp., Pachygrapsus gracilis) (mean: 58 and 38% by dry weight, respectively), emphasizing a short food chain in the mangrove system. Cirripedia and Brachyura dominated the diet in all size classes, however, the prey spectrum narrowed with fish size. The mean daily consumption of Cirripedia and Brachyura was 6.2% body weight of C. psittacus. On average C. psittacus consumed 100.3 g x ha(-1) x d(-1) of Cirripedia and 178.7 g x ha(-1) x d(-1) of Brachyura (wet weight). The predation on Brachyuran crabs--a significant driver of fluxes of organic matter and energy in the system--provides C. psittacus with an important ecological function in the mangrove food web. A plant-animal interaction is proposed where C. psittacus exerts a mutually beneficial cleaning function on the Aufwuchs (Cirripedia and associated epibiota) of Rhizophora mangle stilt roots. Our results and those of other studies suggest that C. psittacus encounter optimum foraging conditions in the mangrove at high inundations at daylight (spring tide-day) whereas darkness and low inundations are linked to poor foraging conditions (neap tide-night). The C. psittacus resource could be used as an alternative income in the region in terms of i) sustainable catch and filet processing for exports to East Asia, ii) developing certified aquaculture methods for breeding puffers for the aquarium trade.     

Solute dynamics in a North Brazilian mangrove: the influence of sediment permeability and freshwater input

Although water in mangrove sediments influences nutrient cycling in both, mangrove forest and estuary, little information exists on seasonal and vertical distribution of dissolved organic and inorganic compounds in the sediment column. We studied the influence of sediment texture and chemistry, permeability (K), tides, and rainfall on dissolved organic carbon (DOC) and nitrogen (DON), dissolved inorganic phosphate (DIP) and salinity in creek and sediment waters of a mangrove in Pará, Brazil. Water samples were taken from boreholes and piezometers in the mangrove forest and from an adjacent tidal creek at neap and spring tides, during the dry and rainy season. Forest sediment was analysed for carbon (C), nitrogen (N), salinity and permeability. Clay, C and N decreased with depth. Sediment permeability (K) was lowest (<0.1 m day⁻¹) in the upper, clay-rich and crab-burrow-free mud layer. In the deeper, fine sand strata, K ranged from 0.7 to 1.8 m day⁻¹. Tidal range in the creek was 3.5 and 5.5 m for neap and spring tides, respectively. Salinity, DOC, DON and DIP in creek water were inversely related to tidal height. Piezometer data revealed significant water level changes in deeper, sandy sediment layer, which followed, time-lagged, the tidal fluctuations. In contrast, tide did not affect the water level in the upper sediment due to low permeability. Compared with creek water, sediment water was enriched in DOC, DON and DIP because of organic matter input and mineralization. In deeper layers, solute concentration was most likely affected by sorption processes (DOC and DIP) and reduction reactions (DIP). During the rainy season, DOC and DON in creek and sediment water were higher than in the dry season. DIP appeared invariant to seasonal changes. In the rainy season, salt flushing from surface sediments resulted in higher salinities at intermediate sediment depths, while in the deeper layers salinity was lower due to exchange with water from the tidal creek.     

Trophic behaviour of juvenile reef fishes inhabiting interlinked mangrove–seagrass habitats in offshore mangrove islets

Stable isotope (δ¹³C and δ¹⁵N) and gut content analyses were used to investigate size‐related feeding habits of four reef fishes (the beaugregory Stegastes leucostictus, the french grunt Haemulon flavolineatum, the schoolmaster snapper Lutjanus apodus and the yellowtail snapper Ocyurus chrysurus) inhabiting an offshore (non‐estuarine) mangrove islet off Belize, Central America. Comparisons of isotopic niche space and Schoener diet similarity index suggested a low to moderate degree of niche overlap between fish size groups. The δ¹³C gradient between mangrove and seagrass prey as well as results of Bayesian mixing models revealed that sampled fishes relied mostly on seagrass prey items. Only small and large juveniles of the carnivorous species L. apodus derived a part of their diet from mangroves by targeting mangrove‐associated Grapsidae crabs and fish prey, respectively. Isotopic niche shifts were particularly obvious for carnivorous fishes that ingested larger prey items (Xanthidae crabs and fishes) during their ontogeny. The utilization of mangrove food resources is less than expected and depends on the ecology and life history of the fish species considered. This research highlights that mangrove‐derived carbon contributed relatively little to the diets of four fish taxa from an offshore mangrove islet.     

The fish assemblage of the intertidal salt marsh creeks in North Bull Island, Dublin Bay: seasonal and tidal changes in composition, distribution and abundance

An intertidal salt marsh fish assemblage inhabiting two creeks on North Bull Island, Dublin Bay was sampled monthly from June 2000 until May 2002. Water temperature and salinity were recorded in situ and samples were also taken for Suspended Particulate Matter (SPM) and Chlorophyll a. All fish caught were weighed and measured and classified into functional guilds. A total of 6,549 individuals comprising 10 fish species from 10 families were recorded within the two creeks. The community was dominated by a few species, a feature common to other estuarine fish populations. Of the 10 species found, the common goby, Pomatoschistus microps, the 3-spined stickleback, Gasterosteus aculeatus, the thick-lipped grey mullet, Chelon labrosus and the flounder, Platichthys flesus contributed 98.4% of all fish sampled. The fish population of the channels at Bull Island, Dublin, was dominated by the resident gobies (true estuarine resident species), but also hosted juveniles of species such as the bass, Dicentrarchus labrax (marine juvenile migrant species). In turn, the nekton populations were dominated by the brown shrimp, Crangon crangon and the fairy shrimp, Palaemonetes varians especially in winter when fewer fish (numbers of species and abundance) were found. Multivariate analysis of fish diversity and abundance revealed a strong seasonal pattern but there was little evidence of difference between creeks, nor of tidal (spring/neap) effects. The estuarine fish using the intertidal marsh creeks have been little studied in Europe yet they play a major role with the decapods in these habitats. This role needs to be quantified for a proper understanding of the system’s function.     

Diel,semi‐lunar and seasonal patterns in the fish community of an intertidal zone of the Yangtze estuary

The structure and temporal variations of the fish community in the intertidal estuarine zone of shallow mud areas have been poorly studied in China. This paper analyses the diel, semi‐lunar and seasonal patterns of fish assemblages in the Yangtze estuary in 2006. Fish were collected by consecutive day and night samplings using tide‐stow‐nets deployed parallel to each other in three stations. A total of 56 fish species belonging to 21 families was caught during the study period. The family Cyprinidae dominated with 25 species. Freshwater fish species were the important dominant commercial fishery species and well represented with five species (sharpbelly Hemiculter bleekeri, goldfish Carassius auratus, bream Parabramis pekinensis, likely‐bream Pseudobrama simony, and glossy yellow catfish Pelteobagrus nitidus) in the three stations. Juvenile fishes dominated the fish community, comprising 93.9% in station 1 and 96.6% in station 2 of the total abundance. The number of fish species in day tides was slightly lower than those in night tides in spring and summer, but the opposite in other seasons. In neap tides, the numbers and abundance of fish species were both lower than those in the spring tides. Fish abundance was lowest in winter, increasing during spring and summer (March–September) in both stations 1 and 2, with obviously large fluctuations in each season. The pattern of habitat selection of fishes could effectively decrease the food competition of intraspecies or interspecies and favour the growth and nursing of young fishes. These findings indicate that the intertidal zones in the estuary may serve as important nursery areas for fish communities.     

Fish use of an inundated saltmarsh flat in a temperate Australian estuary

Abstract Fish associated with Australian saltmarshes have previously been sampled from within creeks or semi-permanent pools on the marsh; this is the first record of fish use of marsh flats inundated on high tides but emergent on low tides. Buoyant pop nets (9 m², 1 mm mesh) were used to collect fish from two areas of the marsh flat on Torrens Island in the Barker Inlet-Port River estuary. South Australia. Fyke nets of the same mesh size were used to collect fish from small creeks draining the marsh flat. Fish were caught in only four of 48 pop net releases, for a total of 19 fish of two species (families Gobiidae and Atherinidae). A total of 1109 fish from six species were caught in creeks draining the same areas, and the two species caught on the flats were the most common species in the creeks. Economically important species were poorly represented, with just four specimens of the mugilid Aldrichetta forsteri (Valenciennes).     

Ontogenetic diet shift, feeding rhythm, and daily ration of juvenile yellowfin goby Acanthogobius flavimanus on a tidal mudflat in the Tama River estuary, central Japan

To ascertain the feeding habits of benthic juvenile yellowfin goby Acanthogobius flavimanus, the gut contents of 599 specimens (15–41 mm in standard length, SL), collected on a tidal mudflat in the Tama River estuary throughout the diel cycle, were examined. The major prey items changed from harpacticoid copepods to errant and sedentary polychaetes at ca. 20 mm SL. Prey width increased with fish size. Fish of 26–28 mm SL fed mainly from sunset to morning, with highest feeding intensity during twilight hours and/or high tide. Based on the gut evacuation rate estimated from a forced feeding experiment in the laboratory and data for the diel change of mean gut-content volume in the field, the daily ration of juvenile yellowfin goby (26–28 mm SL) was calculated to be 13.8 mm³ fish⁻¹ day⁻¹. This volume is approximately equivalent to 3.9 individuals of the errant polychaete Ceratonereis erythraeensis (9.7 mm in body length, BL) or 8.1 individuals of the sedentary polychaete Prionospio japonica (14.8 mm BL), both species occurring abundantly on the mudflat during the study.     

Linkages between seagrass,mangrove and saltmarsh as fish habitat in the Botany Bay estuary,New South Wales

Shallow-water vegetated estuarine habitats, notably seagrass, mangrove and saltmarsh, are known to be important habitats for many species of small or juvenile fish in temperate Australia. However, the movement of fish between these habitats is poorly understood, and yet critical to the management of the estuarine fisheries resource. We installed a series of buoyant pop nets in adjacent stands of seagrass, mangrove and saltmarsh in order to determine how relative abundance of fishes varied through lunar cycles. Nets were released in all habitats at the peak of the monthly spring tide for 12 months, and in the seagrass habitat at the peak of the neap tide also. The assemblage of fish in each habitat differed during the spring tides. The seagrass assemblage differed between spring and neap tide, with the neap tide assemblage showing greater abundances of fish, particularly those species which visited the adjacent habitats when inundated during spring tides. The result supports the hypothesis that fish move from the seagrass to the adjacent mangrove and saltmarsh during spring tides, taking advantage of high abundances of zooplankton, and use seagrass as a refuge during lower tides. The restoration and preservation of mangrove and saltmarsh utility as fish habitat may in some situations be linked to the proximity of available seagrass.     

Tower construction by the manicure crab <Emphasis Type="Italic">Cleistostoma dilatatum</Emphasis> during dry periods on an intertidal mudflat

Animals living on upper intertidal mudflats experience habitat desiccation during neap tides when water does not flood the habitat. Individuals of the manicure crab Cleistostoma dilatatum construct cone-shaped towers at the entrance of their burrows, in which they remain during neap tides. These towers are the tallest known structures compared to body size built by crabs living on intertidal flats. The frequency of tower construction followed semilunar tidal cycles with most building done prior to neap tides when few crabs were active on the mudflat surface. Bigger crabs tended to make taller and wider towers with a wider pinhole on the top. These towers may regulate the microclimate in burrows.     

Inundation timing,more than duration,affects the community structure of California vernal pool mesocosms

The food source utilization and trophic relationship of the fish assemblage in the Red River mangrove ecosystem, Vietnam were examined using dual isotope analysis. The carbon and nitrogen stable isotope signatures of 23 fish species ranged from ?24.0 to ?15.7‰ and from 8.8 to 15.5‰, respectively. Cluster analysis based on the δ¹³C and δ¹⁵N signatures clearly separated the mangrove fish into five feeding groups, representing detritivores, omnivores, piscivores, zoobenthivores, and zooplanktivores, which concurred with the dietary information. The results suggested that mangrove carbon contributed a small proportion in the diets of the mangrove fish, with dominant food sources coming from benthic invertebrates, including ocypodid and grapsid crabs, penaeid shrimps, bivalves, gastropods, and polychaetes. The δ¹⁵N values showed that the food web structure may be divided into different trophic levels (TLs). The lowest TLs associated with Liza macrolepis, Mugil cephalus, and Periophthalmus modestus; 18 fish species had TLs between 3.0 and 3.8; and Pennahia argentata had the highest TL (c. 4.0).     

Food consumption of five deep‐sea fishes in the Balearic Basin (western Mediterranean Sea): are there daily feeding rhythms in fishes living below 1000 m?

Predation and food consumption of five deep‐sea fish species living below 1000 m depth in the western Mediterranean Sea were analysed to identify the feeding patterns and food requirements of a deep‐sea fish assemblage. A feeding rhythm was observed for Risso's smooth‐head Alepocephalus rostratus, Mediterranean grenadier Coryphaenoides mediterraeus and Mediterranean codling Lepidion lepidion. Differences in the patterns of the prey consumed suggest that feeding rhythms at such depths are linked with prey availability. The diets of those predators with feeding rhythms are based principally on active‐swimmer prey, including pelagic prey known to perform vertical migrations. The diets of Günther's grenadier Coryphaenoides guentheri and smallmouth spiny eel Polyacanthonotus rissoanus, which did not show any rhythm in their feeding patterns, are based mainly on benthic prey. Food consumption estimates were low (<1% of body wet mass day^?1). Pelagic feeding species showing diel feeding rhythms consumed more food than benthic feeding species with no feeding rhythms.     

Temporal Variations in Fish Catch Using Pop Nets in Mangrove and Saltmarsh Flats at Towra Point,NSW, Australia

Fish assemblages utilising saltmarsh and mangrove during spring tides were surveyed over a 12-month period using buoyant pop nets. A total of 48 net releases in the saltmarsh identified 16 species, at a density of 0.56 fish m⁻², with six species being of commercial importance. The same number of releases within the mangrove collected a total of 23 species at a density of 0.76 fish m⁻². However, fish density was higher within the saltmarsh than the adjacent mangrove when corrected for water volume. Multidimensional scaling revealed different assemblages of fish in the two habitats, with higher numbers of Ambassis jacksoniensis and Pseudomugil sp. in the saltmarsh and higher numbers of Mugilogobius sp. and Acanthopagrus australis in the mangrove. The result suggests a potentially significant role for saltmarsh as a fish habitat in the estuaries of southeast Australia.     

Microbial carbon oxidation rates and pathways in sediments of two Tanzanian mangrove forests

Temporal and spatial variations in benthic metabolism and anaerobic carbon oxidation pathways were assessed in an anthropogenically impacted (Mtoni) and a pristine (Ras Dege) mangrove forest in Tanzania. The objectives were (1) to evaluate how benthic metabolism is affected by organic carbon availability; (2) to determine the validity of diffusive release of CO₂ as a measure benthic carbon oxidation; and (3) to assess the partitioning of anaerobic carbon pathways and factors controlling the availability of electron acceptors (e.g. oxidized iron). Microbial carbon oxidation measured as diffusive exchange of O₂ and CO₂ (32?C67 and 28?C115 mmol m^?2 day^?1, respectively) showed no specific temporal patterns. Low intertidal sediments at Mtoni fed by labile algal carbon of anthropogenic origin had higher diffusive CO₂ release than high intertidal sediments that primarily received less reactive mangrove detritus. Diffusive release of CO₂ apparently underestimated total sediment carbon oxidation due to CO₂ loss from deep sediments via emission through biogenic structures (i.e. crab burrows and pneumatophores) and porewater seepage into creeks. We propose that diffusive fluxes in the present mangrove sediments are roughly equivalent to depth-integrated reactions occurring in the upper 12 cm. Anaerobic carbon oxidation was dominated by FeR irrespective of anthropogenic influence in sediments where the oxidizing effects of biogenic structures increased the Fe(III) level. More than 80% of the anaerobic carbon oxidation in Mtoni and Ras Dege sediments was due to FeR when reactive Fe(III) exceeded 30 ??mol cm^?3. The anthropogenic influence at Mtoni was primarily noted as up to one order of magnitude higher denitrification than at Ras Dege, but this process always accounted for less than 1% of total carbon oxidation. It is noteworthy that organic and nutrient enrichment of anthropogenic origin in Mtoni has no measurable effect on microbial processes, other than carbon oxidation in the low intertidal area and denitrification throughout the forest, and indicates a strong resilience of mangrove environments towards disturbances.     

Short-term foraging patterns of individual cornetfish, Fistularia commersonii, based on stomach content analysis

Stomach contents of 75 specimens of the cornetfish Fistularia commersonii, collected in shallow water off Kuchinoerabu-jima Island, southern Japan were analyzed. Many fish contained multiple prey. The prey were mostly fish, grouped into two types, pelagic and reef fishes. The size of prey increased as the size of F. commersonii increased. All the small individuals (<50 cm SL) had fed on only small reef fish. However, most of the large individuals (>50 cm SL) had fed on either prey type. Both pelagic and reef fishes usually occurred simultaneously in shallow water, suggesting that most of the large cornetfish may selectively hunt either type of prey. Received: February 27, 2001 / Revised: September 11, 2001 / Accepted: October 10, 2001     

The climbing behaviour of Cerithidea anticipata (Mollusca: Gastropoda): The roles of physical and biological factors

Abstract Many molluscs in tidal wetlands climb trees as the tide rises, a behaviour usually assumed to be a means of avoiding subtidal predators. Some species are more active during neap tides, when the access of subtidal predators to the forest is limited, but rest on trees during spring tides. Cerithidea anticipata, which inhabits the mangrove forests around Darwin Harbour (Northern Territory, Australia), displayed almost exactly the opposite pattern. This species climbed higher, and was less active, during neap tides that did not flood the forest than during spring tides. In experiments with tethered snails, individuals prevented from climbing died during neap tides, apparently from physiological stress. Further, individuals resting on trees around clearings, usually selected shaded sites. These results suggest that the major reason C. anticipata climbed was to avoid physiological stress during neap tides, not subtidal predators during spring tides. There was some evidence of predation under the canopy, but the rate was relatively low and the species responsible appeared to be resident in the forest.     

Diet of the Atlantic bonito Sarda sarda (Bloch, 1793) in the Northeast Aegean Sea

Seasonal and size‐related patterns in feeding habits of the Atlantic bonito (Sarda sarda) in the Northeast Aegean were investigated over a 2‐year period May 2007 – May 2009 based on analysis of stomach contents of 134 fish ranging from 266–655 mm fork length. The fish were caught by purse‐seine boats operating around the islands of Lesvos and Chios (Greece). Of the stomachs examined, 46% contained at least one prey item and significant seasonal and size‐related patterns were found in the occurrence of non‐empty stomachs. The overall diet composition in terms of numerical importance was 71% fish, 28% crustaceans and 1% cephalopods. Of the fish, Engraulidae (Engraulis encrasicolus) were the dominant prey taxon, followed by Centracanthidae (Spicara spp.) and then Clupeidae (Sardina pilchardus). Statistically significant monthly variation in diet was apparent, suggesting that S. sarda take advantage of seasonally abundant prey fish in the study area, but no size‐related variation in the importance of the main prey species was detected.     

Effect of winter feeding and starvation on the growth performance of young‐of‐year (YOY) great sturgeon,Huso huso

The objective of this study was to evaluate the feeding rate of the great sturgeon (Huso huso) young of the year (YOY) and to investigate the effects of different feeding rates in maintaining the weight of fish during short periods of winter starvation. Six feeding rates of 0.2, 0.4, 0.6, 0.8, 1.0% body weight (BW) day^?1 and feeding to satiation were considered for the first experiment. Each feeding rate was randomly assigned to three replicate tanks, with continuous feeding throughout a 5‐week winter period of water temperatures below 10°C. Fifteen fish were held in each of 18 tanks with an average initial body weight of 219.6 ± 6.9 g. After 5 weeks of feeding, the best performance was observed in fish fed 1% BW day^?1, but negative growth was observed in fish fed 0.2% BW day^?1. In the second experiment, fish were deprived of feed for 3 weeks at winter temperatures. Weights and condition factors of all fish decreased during starvation, while the differences in mean weight before and after the starvation period were not significant in fish fed a level of 0.2% BW day^?1 and those fish fed to satiation. No mortality was recorded in either experiment. Results of this study indicate that a feeding rate of 1% BW day^?1 would be sufficient for commercial fish farming of YOY of this species to maintain them over winter. Also, to maintain fish weights and prevent weight loss in overwintering ponds, a feeding rate of around 0.3% BW day^?1 seems appropriate for hatcheries.