Mean Condition Factor Research Articles

Length-weight relationship, length-length relationship and condition factor of some fish populations in Büyükçekmece Reservoir (İstanbul, Turkey)

In present study, length-weight relationship, length-length relationship and condition factor values were calculated for 11 freshwater fish species of Buyukcekmece Reservoir. Fish specimens were collected by gillnets having different mesh size between March 2009 and February 2010, monthly. The values of the exponent b of the length–weight relationships varied between 2.727±0.020 and 3.381±0.001. The lowest mean condition factor was estimated 0.74±0.08 for C. taenia while the highest value was recorded as 1.72±0.15 in C. gibelio .

Contribution to the knowledge of the feeding and growth biology of the Iranian cichlid,Iranocichla hormuzensis

AbstractGrowth parameters and feeding indices, such as condition factor (CF), of the Iranian cichlid, Iranocichla hormuzensis, the only native cichlid of Iran, were investigated during the period between August 2008 and August 2009. The estimated b value (the slope in length–weight equation) for males and females was 2.94, which is not significantly different from 3 that is indicative of isometric growth (p > 0.05). There was a significant difference (p < 0.05) between mean CFs of males and females. Males in the length group of 56–85 mm showed a higher CF than those in smallest (46–55 mm) and largest (86–100 mm) length groups. A total of 432 guts (217 of males and 195 of females) were investigated during the thirteen-month study period. The mean gut length, gut weight, relative gut length (RGL) and relative gut mass were significantly higher for males than females (p < 0.05). The RGL of males ranged between 1.12 and 8.24 (5.31 ± 1.26) and that of females between 0.58 and 10.43 (4.55 ± 1.53). Although I. h...

Food and Feeding, Length-Weight and Condition Factor of the Catfish &amp;lt;i&amp;gt;Synodontis membranaceus&amp;lt;/i&amp;gt; (EtieneGeoffroy Saint Hilaire, 1809) (Osteichthyes: Mochokidae) from Lower Benue River, Makurdi, Nigeria

Food and Feeding, length-weight and condition factor of the Catfish Synodontis membranaceus from the Lower Benue River at Makurdi, Nigeria, was studied for 12- month period from July, 2013 to June, 2014. A total number of 202 specimens, comprising of 101 males and 101 females at a ratio of 1:1 were studied. The Length-Weight Relationship (LWR), correlation coefficient (r) for all males and females were highly positive and significant at (P<0.01), with r values of 0.972 for males, 0.899 for females and 0.952 for combined sexes. The mean b values (regression coefficient) were 2.68 in all the males, 2.46 in all the females and 2.63 in combined sexes indicating that all the sexes had negative allometric growth pattern. The mean condition factor (K) for both sexes ranged from 2.21-3.35. The lowest K range (1.81) for males was observed in July, 2013 while the highest K range (3.05) was observed in April, 2014. Similarly, the lowest K range (1.83) for females was observed in August, 2013 with the highest K range of 3.14 in the same month. Out of the 202 stomachs examined, only 9 males (8.91%) and 5 females (4.95%) had empty stomachs, about 91.09% of males and 95.0% of females had varied quantities of food items in their stomachs. Synodontis membranaceus in the Lower Benue River was found to be omnivorous, feeding on food items, which included artificial meal, plant remains, variety of algae, insect parts and larvae, bivalves (Molluscs), crustaceans, protozoa, worms, detritus, sand particles and mud and many unidentified quantities of food items.

Effects of river damming in Neotropical piscivorous and omnivorous fish: feeding, body condition and abundances

ABSTRACT The increase in abundance of small-sized fishes is common after a reservoir is formed. There is an increase in the consumption of fish, from typically piscivorous fish to opportunistic species that take advantage of abundant resources. This study aims to evaluate the effects of diet changes induced by damming on the feeding activity and condition factor of typically piscivorous (Hoplias aff. malabaricus and Oligosarcus longirostris ) and opportunistic (Astyanax lacustris (ex Astyanax altiparanae ) and Pimelodus britskii ). Sampling was conducted before and after the impoundment in the Iguaçu River in the region of Salto Caxias, Paraná State, Brazil. Stomach contents were analysed by the volumetric method. Feeding activity and body condition were inferred by the mean stomach repletion index and the mean condition factor. Typically piscivorous species presented a general tendency of decreased feeding activity and increased condition factor, while opportunistic species, presented a decrease in condition and feeding activity in the most affected sites. The increase in the condition factor of piscivorous fish suggests that these species benefit by the increased abundance of small size prey fish. Some opportunist species that do not have adjustments for the piscivorous diet, regardless of the intensity of consumption and resource availability, can suffer negative reflex when adopting a piscivorous diet.

Growth and reproduction of a marine fish, Atherina boyeri (Risso 1810),in a freshwater ecosystem

Atherina boyeri (Risso, 1810) has established abundant and successful populations in inland waters in Anatolia, although it is known as a marine species. In this study, the growth and reproduction properties of A. boyeri in the Hirfanli Reservoir were studied. Age determinations based on scale readings showed that the population had a 4-year life cycle. Sampled individuals ranged between 5.76 and 115.65 mm in total length and 0.01 and 10.48 g in total weight. The von Bertalanffy growth parameters for females were L∞ = 156.78, k = 0.197, and t0 = ?0.197; for males, L∞ = 151.02, k = 0.148, and t0 = ?0.148. Mean condition factor values, estimated from eviscerated weight, varied between 0.49 and 0.60. The length weight relationship of A. boyeri indicated allometric growth, whereas the b value for females, males, and juveniles was 3.29, 3.23, and 3.50, respectively. The sex ratio was 1:1.14 in favor of females. The reproductive season, evaluated by the gonadosomatic index, extended from May to July. Mature egg diameter ranged from 0.64 to 1.73 mm. The mean total fecundity increased with age. In the Hirfanli Reservoir, certain life-history features of A. boyeri, such as short life cycle and increasing fecundity, indicated that this species has the potential to become dominant in freshwater systems.

Length-weight Relationship, Condition Factor and Feeding Habits of Synodontis clarias (Linnaeus, 1758) in the Lower River Benue at Makurdi, Nigeria

The Length-Weight Relationship (LWR), Condition factor (K) and feeding habits of Synodontis clarias (Linnaeus, 1758) were investigated over a 24 month period from January, 2009 - December, 2010. A total number of 163 specimens comprising of 74 females and 89 males with the size range of 7.60 – 20.00cm and the mean of 12.72± 0.258cm were investigated. The weight ranged from 13.12 – 607.30g with the mean of 65.83± 0.897g. The LWRs for the females, males and combined sexes had the r values of 0. 8415, 0.9463 and 0.8703 respectively. The mean condition factor K was 3.3667, 2.6868 and 2.9954 for the females, males and combined sexes respectively. The regression coefficient b was 1.9408, 1.8799 and 2.1359 for the females, males and combined sexes respectively indicating negative allometric growth pattern for the species. Out of the 163 stomachs examined for food items, 88 (53.99%) were empty while 75 (46.01%) contained a wide range and varying quantities of food items indicating that S.clarias in River Benue is omnivorous.

Lenght-weight relationship and condition factof of Leuciscus niloticus (De Joahhis 1853) from Epe Lagoon, Lagos State, Nigeria

Leuciscus niloticus samples were obtained from Epe lagoon, Lagos state, Nigeria. The fish samples were designated into pooled, male and female sex respectively. Length-weight relationship was carried out to investigate the correlation value, growth pattern and the condition factor (k) of pooled, male and female Leuciscus niloticus . In this study, the growth pattern of pooled, male and female Leuciscus niloticus from Epe lagoon shows that the “b” values were 2.56, 2.62 and 2.38 respectively, showing that all the fish sampled exhibited negative allometric growth pattern. The overall length weight regression equation for pooled was (Log W = -1.679 + 2.559 log TL), (r = 0.898), and also the length-weight equations of males and females (Log W = -1.759 + 2.618 log TL) (r=0.919), (Log W = -1.449 + 2.384 log TL) (r=0.870) respectively. The mean condition factor (k) of Leuciscus niloticus was 0.55 ± 0.08 for pooled, 0.54 ± 0.08 and 0.55 ± 0.09 for both male and female respectively indicate poor adaptation of the fish in the Epe lagoon.

Growth Performance and Feed Utilization of Russian Sturgeon Acipenser gueldenstaedtii Brandt&amp;Ratzeburg, 1833 in Grow-out Phase Cultured in the Black Sea

The aim of present study was to determine the growth performance of Russian sturgeon Acipenser gueldenstaedtii throughout 5 years and to investigate problems encountered in grow-out phase. Fish samples (2750.88±351.18 g, 80.18±6.49 cm mean±SD) were equally stocked into fiberglass tanks, three replicate per treatment and fed for 5 years. Gain of weight and length, Specific Growth Rate (SGR), Condition Factor (CF) and Feed Conversion Ratio (FCR) were determined. Our results indicated that mean final length and weight were 106.34±2.79 (cm) and 6651.16±3.16 (g). The mean condition factor (CF) at year 5 was 0.51. FCR values fluctuated and the highest value of food conversion rate (FCR) was determined in 4th year. During the rearing period of Russian sturgeon, SGR values decreased dramatically from 2.88 to 1.83. In conclusion, slow growth was determined in Russian sturgeon A. gueldenstaedtii. Therefore, there is need for extensive evaluation and comparison of data obtained from field studies and those obtained from laboratory studies.

Some Biological Characteristics of the Daysciaena albida (Cuvier 1830), on Largest Brackish Water Lagoon of India

An attempt to study length-weight relationship (LWR), condition factor and reproductive aspects of Daysciaena albida was done in Chilika lagoon over one year. The fish specimens for the biological study were collected from landing centers of central and northern sector during pre-monsoon, monsoon and post-monsoon seasons. The LWR from total length and body weight were computed both by sex and seasons. The equations found from the relationships were y=0.010x2.992 for male, y=0.010x2.998 for female and y=0.010x2.996 as unsexed specimens. The highest condition factor (K) value was recorded during monsoon (1.42±0.08) followed by post-monsoon (1.4±0.09) and the lowest (0.92±0.11) during pre-monsoon seasons. The mean condition factor was registered as 1.06±0.09 in all the seasons of unsexed specimens. Among sex, males registered slightly higher K value than females. For reproductive study, maturation stages, gonad somatic index (GSI) and gastro somatic index (GaSI) were analyzed seasonally. Considering maturation stages highest maturation stages (stages 4 to 7) obtained during pre-monsoon season (in both sexes) which are considered as matured conditions for fish. The highest GSI was registered during pre-monsoon followed by postmonsoon and the lowest was during monsoon season among both the sexes. The GaSI value was lowest during pre-monsoon among males and gradually increased during monsoon and postmonsoon. But in case of female, lowest value was during monsoon and again increased afterwards and was highest in pre-monsoon. ECOPRINT 21: 15-21, 2014DOI: http://dx.doi.org/10.3126/eco.v21i0.11900

Ladik Gölü (Türkiye)’ndeki Tahta Balığı, Blicca bjoerkna (L., 1758)’nın Yaşı, Büyümesi ve Üreme Dönemi

The white bream, Blicca bjoerkna (L., 1758) specimens ( n =434) were collected from Lake Ladik between November 2009 and October 2010 in order to determine the age, growth, and reproductive season. Fork lengths and weights of these samples varied between 11.5-24.3 cm and 22.80-259.00 g, respectively. Age estimates obtained from scales and vertebrae were compared to determine the most reliable bony structure for ageing. The precision analyses indicated that scales were the most appropriate hard structures for determining the age of white bream. Ages of all the specimens ranged from I to VI years and age group III was dominant. The parameters of the von Bertalanffy growth equations were calculated as L ∞ = 32.85 cm, W ∞ = 707.76 g, k = 0.11 year -1 and t 0 = -2.64 year, and the growth performance index ( Φ' ) value was computed as 2.074 for combined sexes. Fork length-weight relationship was found to be W = 0.0066 FL 3.317 . The mean condition factor was the highest in August and the lowest in October. The gonadosomatic index values showed that the reproduction occurred between May and June.

Determination of Morphometric Relationship and Condition Factors of Four Cichlids from Golinga Reservoir in Northern Region of Ghana

Length-weight relationship and condition factor have severalapplications on fish biology, physiology, ecology and fisheries assessment. A six-month study was conducted from November 2013 to April 2014 to determine the length-weight relationship and condition factor of four major cichlids namely Oreochromis niloticus (Nile tilapia), Hemichromis fasciatus (Banded jewelfish), Sarotherodon galilaeus (Mango fish) and Tilapiazillii (Red-belly tilapia) to fill a knowledge gap and provide useful information for fisheries management and conservation in the Golinga reservoir using the length-weight based model. Samples were collected twice every month with gillnets from commercial fishermen. The length-weight relationship had a strong positive correlation (r>0.8) for the four species. Oreochromis niloticus exhibited isometric growth (b = 3.07) whilst Hemichromis fasciatus (b = 2.81), Sarotherodon galilaeus (b = 2.91) and Tilapia zillii (b = 2.75) showed negative allometric growth. Mean condition factor (K) values were greater than one (3.66-4.88) for all the species and varied monthly. The study provided new information on length-weight parameters for the four cichlids.

Age and growth of Boops boops (Linnaeus, 1758) in Izmir Bay, Aegean Sea, Turkey

The present study was conducted to determine the age relationships in lengths and weights of Boops boops (Linneaus, 1756) in Izmir Bay, central Aegean Sea. A total of 932 specimens (503 females and 429 males) were caught by gillnet, trammel net and a combination thereof on a monthly sampling basis from November 2008 through October 2009. Total length and weight of sampled fish ranged from 11.3 to 27.9 cm and from 12.2 to 261.7 g, with a mean of 19.6 cm and 82.7 g, respectively. Length-weight relationships for all individuals were described by the parameters a = 0.0050, b = 3.237 and r² = 0.956. The von Bertalanffy growth curve fitted to the lengths-at-age provided parameters of L∞ = 29.87 cm k = 0.243 and to = −0.98 for males and L∞ = 30.79 cm, k = 0.239 and to = −0.90 for females. Based on otolith readings, age determinations varied from 1 to 5 years. Maximum age was 5 years in age group 2, with 29.84 and 37.97% for males and females, respectively. The overall 1 : 1.17 sex ratio of males to females was significantly biased toward females (P < 0.05). There was no statistical difference in the mean condition factor (P > 0.05), with a value of 1.028 for the entire population. The growth performance index (Φ’) was 2.33 and 2.36 for males and females, respectively. Results were similar to other geographical areas, which suggests that a common fisheries management might be possible.

English

Length-weight relationship (LWR) and condition factor of seven fish species from the Temengor Reservoir, Peninsular Malaysia were analyzed. A total of 1155 individuals belonging to two families namely Nandidae and Cyprinidae were measured and weighed. The most highly represented family was Cyprinidae which comprised six species. Among these seven species, three species generally showed positive allometric growth, two species showed isometric growth and the other two species showed negative allometric growth. The exponent b value of LWR ranged between 2.601 (Oxygaster anomalura) and 3.157 (Cyclocheilichthys apogon) with a mean of 2.983. The lowest mean condition factor, K was recorded in O. anomalura (0.648 ± 0.131) while the highest value was observed in Pristolepis fasciata (2.194 ± 0.153). This study has contributed to the knowledge of fish populations in this economically important area that could assist fishery management scientists in carrying out future ecological studies in line with the strategies of conservation, restoration and management.

Ovarian maturation and spawning season of Por’s goatfish Upeneus pori (Mullidae) from Mediterranean Sea, Egypt

The body length of Por’s goatfish (Upeneus pori) at 50% sexual maturity is estimated and the results indicate that L50 is 10.6 cm. Monthly variations of the gonadosomatic index indicate that the spawning occurs mainly in May. Mean hepatosomatic index significantly increases from February to May, peaking in March (2%) and April (1.91%) during vitellogenesis and spawning. Mean condition factor values vary slightly from 0.98% in December to 1.17% in November. Based on histological investigation of female’s oocyte development, five maturity stages are demonstrated. Ovarian maturity is defined by the maturation stage of the most advanced oocytes, and it is divided into four phases. By using the monthly changes in the percentage frequency of ovarian phases, the ovarian cycle of U. pori is divided into three periods: a long period of early oogenesis (November to February), a short period of vitellogenesis (February to April) and a spawning period from April through June with peak activity in May.

Assessment of the water quality parameters in relation to fish community of Osinmo reservoir, Ejigbo, Osun State, Nigeria

Physicochemical indices of water body changed seasonally and this necessitated an investigation to assess the water quality parameters of Osinmo reservoir in relation to its fish species. The water quality parameters were measured using standard methods. Results obtained show that the reservoir is alkaline in nature with dissolved oxygen concentration (1.8-7.2 mgl-1) and alkalinity (64 CaCO3 mgl-1-108 CaCO3 mgl-1) which were within the optimum range for growth and survival of fish. Four families of fish comprising eight species were encountered. The sex-ratio of five species which were statistically different (P&lt;0.05) indicatedreproductive efficiency populations while other fish species whose sex-ratio differed insignificantly (P&gt;0.05) revealed a growing population. The well-being of the fish species was adequate as observed in the least meancondition factor of 0.666±0.057 in C. gariepinus and the highest mean of 2.000±0.242 in S. galilaeus. The productivity of the reservoir can be improved through proper management of the water body.Keywords: Water quality, fish abundance, diversity, fish biometrics, sex-ratio, condition factor.

Does reduced feeding prior to release improve the marine migration of hatchery brown trout Salmo trutta smolts?

The aim of this study was to test the hypothesis that hatchery brown trout Salmo trutta smolts, with 50% reduced or no feeding over the last 5 months before release, were more likely to migrate to the sea than individuals with standard feeding ratios. The juvenile fish were divided into three groups 176 days before release: (A) with no feeding, (B) with 50% and (C) with 100% feeding. To study their seaward migration, 40 fish from each feeding group were tagged with acoustic transmitters and tracked by automatic listening stations in the River Nidelva, Trondheim, Norway, its estuary and in the nearest marine environment. At the time of release, mean condition factor was significantly lower in group A and the fish from groups A and B had higher levels of Na+, K+-ATPase. Significantly more fish from group A migrated to the sea, but the rate of downstream progression from release to the estuary did not differ between the three groups. In conclusion, the S. trutta smolts with no access to food in the last 176 day before release were more likely to migrate to the sea. Fish from all three feeding groups, however, appeared to smoltify and had the same rate of downstream progression to the estuary. This indicates that differences in migratory behaviour between individuals from the three feeding groups begin from the time when the fish reach saline waters. It is suggested that feeding in hatcheries has to be greatly reduced (by 50% or more) over several months to have a pronounced effect on the migratory behaviour in S. trutta.

Comparative Assessment of Growth Performance and Economics of Production of Clarias gariepinus Fingerlings in Ponds and Tanks

An experiment was conducted to compare the growth and economics of producing Clarias gariepinus in ponds (6.4x5.4x1.5m 3 ) and tanks (2.5x1.1x1.2m 3 ) for 56days. Fingerlings of Clarias gariepinus (mean weight, 1.80g and body length, 4.40cm) were stocked at 250 and 50 fish separately into each pond and tank in duplicates. Fish were fed a commercial feed containing 45% crude protein at 5% body weight. It was divided into two halves and fed at 1000 and 1600hours daily. At final harvest, the total yield of fish was significantly greater (P 0.05) in mean weight gain (13.75+0.95g, 13.44+0.95g), condition factor (0.92 +0.03, 0.91+0.03) and feed conversion ratio (0.56+0.01, 0.51+0.01) between fingerlings stocked in pond and tank. Fish in pond had higher percentage weight gain and specific growth rate while survival rate ranged 74.11+0.54-88.80+0.54% in the culture media. Net profits obtained were N4300 (pond) and N2250 (tank). The benefit: cost ratio was higher for tank (1.38) than for pond (1.19). The pond environment appeared more productive while the tank was more economical with higher benefit in this study.

Age structure and growth of bluefin tuna (Thunnus thynnus, L.) in the capture-based aquaculture in the Mediterranean Sea

Abstract The principal objective of this study was to estimate the age and growth, length–weight relationships and condition factors of the Mediterranean bluefin tuna ( Thunnus thynnus ) in a capture-based aquaculture farm and to reveal possible differences among farmed (reared in sea cages for 18 months), fattened (reared in sea cages for 6–7 months) and wild specimens. Moreover, to determine the age composition of the fish destined for fattening and farming operations with the current lack of demographic information makes the bluefin tuna stock assessment extremely difficult. For this purpose, a total number of 2096 specimens (ranging from 102 to 295 cm in fork length and from 33 to 540 kg in round weight) were sampled, from the Greek Bluefin Tuna Farm (GR 01/2004), in the Ionian Sea (38 ° 26′ 0.07ʺ N, 21 ° 1′ 48.85ʺ E), during the five year period 2007–2011. In addition, length and weight literature data from wild specimens captured in the central Mediterranean Sea were analyzed. The results revealed high percentage difference in weight between wild and reared in sea cages bluefin tuna of the same fork length, which reached a maximum of 43.9% in large specimens. The condition factor of the reared in sea cages bluefin tuna ranged from 1.24 to 3.16 with a mean value of 2.04 ± 0.19. The mean condition factor of the farmed specimens (1.92 ± 0.17) was lower than that of the fattened specimens (2.08 ± 0.15). This difference was consistent both in younger and older specimens in the sample. Estimated ages that were obtained using the caudal vertebrae of 619 reared in sea cages specimens ranged from 5 to 18 years. It was observed that the age of fish has a significant impact on the condition factor. The comparison among the mean condition factor values of each age class revealed that older fish (10–20 years old) present higher values than younger ones (5–9 years old). With a view to estimating the precision of the aging method, the Average Percent Error (APE) and the Coefficient of Variation (CV) were calculated (APE = 1.89% and CV = 2.46%). The von Bertalanffy growth model was fitted to mean lengths at estimated ages and the growth parameters were determined (L ∞ = 360.3 cm, k = 0.083 yr − 1 , t 0 = − 0.942 yr).

Seasonal distribution and Condition factor of Clarias gariepinus from polluted Oluwa River, Nigeria

The Condition factor (k) of the Clarias gariepinus species in Oluwa River, Nigeria was done. Samples were collected monthly over a two-year period from July 2010 to June 2012 and were identified using standard method. They were subjected to morphometric studies including determination weightand lengths. Condition factor was calculated in relation to sex and sizes. The mean condition factor for males exhibited a range of 0.81±0.03 - 1.97±0.33 (mean 1.34±0.10) while those of females exhibited a range of 0.64±0.00 - 2.00±0.21 (mean 1.31±0.09)and that for combined sexes ranged from 0.54±0.27 to 1.94±0.11 (mean 1.31±0.10). In relation to total length range (TLR), males had the highest condition factor at 34.00 - 36.90cm while the least was recorded in 70.00-72.90cm range. Females had the highest condition factor in the range 37.00- 39.90cm and the least at range 70.00-72.90cm. For the combined sexes, highest condition factor was recorded in the TLR 37.00-39.90cm while the least was also recorded in the TLR 70.00-72.90cm. The mean 'k' indicated that male fishes were not in good condition in the months of July, August and November. Generally, male fishes and smaller sized fishes were found to be better suited to the environmental condition than the female and bigger fishes.

Effects of Flow Reduction on a Whitespotted Char Population in a Japanese Mountain Stream

AbstractI evaluated the effects of long‐term (about 270 d/year) and large‐volume (83.3% at mean flow) reductions in stream flow on a population of Whitespotted Char Salvelinus leucomaenis. I compared a range of biological parameters (density, biomass, condition factor, and age composition) between populations of char in the free‐flowing (above dam) and regulated (below dam) sections of a Japanese mountain stream over a 4‐year period. The density and biomass of age‐1 and older fish was significantly lower in the regulated section than in the free‐flowing section: 32.8% reduction in density and 42.5% in biomass. The mean condition factor of age‐1 and older fish was significantly lower in the regulated section. In addition, the percentage of age‐2 and older fish in the total catch was significantly lower in the regulated section. Except for flow, the physical environment was similar in both the free‐flowing and regulated sections. Thus, the changes I observed in the regulated section were likely caused by flow reduction. I hypothesize that a decrease in food availability associated with the reduction in flow caused the decrease in density and condition factor in the regulated section. I also speculate that an increase in density in the pools due to flow reduction resulted in increased aggression among conspecifics. In turn, this results in an increase in the emigration of individuals, particularly older and larger fish, in the regulated section. The decreases in the density, condition factor, and the number of older and larger fish following the reduction in flow probably explain the decrease in biomass in the regulated section.Received November 20, 2012; accepted July 15, 2013