Length-fecundity relationships of Nigerian fish populations

Parameters of the exponential body length (L)-fecundity (F) relationship of the form F=a.L super(b) are presented for 47 populations and 26 species of Nigerian fishes. Estimates of b varied between 1.563 (Ilisha africana) and 5.771 (Barbus callipterus) with a mean of 3.054 (s.d. = 1.024). The maximum sizes of fish populations examined did not significantly influence the relative magnitudes of b. The parameters Alpha and Beta of the linear length-fecundity relationships of the form F = Alpha + BetaL are also presented for five fish populations. Estimates of Beta ranged from 243.5 (Chrysichthys walkeri) to 1,334,895 (Tilapia mariae).

Length-weight relationships of tuna baitfish from the Lakshadweep Islands, India

The present study reports the length-weight relationship of 11 species of baitfish from the pole and line fishery at Minicoy and S. delicatulus from the fishery at Agatti, Bangaram and Perumal Par.

Length-weight relationships of bivalves from coastal waters of Korea

Parameters a and b of the length (L)-weight (W) relationship W = a · Lb are presented for 17 commercial bivalve species collected from the southwest coastal waters of Korea. Estimates of b varied between 2.44 (Atrina pinnata japonica) and 3.31 (Scaphara broughtonii) with a mean of 2.891 (± 0.212). A total of 2 107 specimens were analyzed for this study. The length-weight relationship was isometric in most of the species.

Length-girth relationships of Barbodes gonionotus and Hampala macrolepidota in the Jatiluhur reservoir, Indonesia

The length-girth relationships of Javanese carp (Barbodes gonionotus) and hampal carp (Hampala macrolepidota) in the Jatilujur Reservoir, Indonesia were examined. The equations derived from estimating the maximum girth of Javanese carp are G sub(m) = -1.19 + 0.80L, and for the hampal carp, G super(m) = -0.47 + 0.62L. Models relating head girth to total length are also given. The relationship between G sub(m) (maximum girth) of fish caught and gillnet mesh size is also briefly discussed.

Length-weight relationships of soft-bottom demersal fishes from Jalisco and Colima states, Mexico

The parameters a and b of the length-weight relationship of the form W=aL super(b) were estimated for 24 species of soft bottom demersal fishes caught on the continental shelf off Jalisco and Colima states, Mexico. The estimates of b ranged from 2.74 to 3.33. The mean of the b values is 3.02 with a standard deviation of 0.15.

Length-weight relationships of Lake Kariba fishes

The parameters a and b of the length-weight relationship of the form W = aL super(b) were computed for 40 species from tables/graphs presented in E. Balon's Fishes of Lake Kariba, Africa.

Growth and length-weight parameters of Pacific mackerel (Scomber japonicus) in the Gulf of Guayaquil, Ecuador

The seasonally oscillating growth parameters and length-weight relationships for Scomber japonicus caught in the Gulf of Guayaquil, Ecuador, were determined based on length-frequency data from 1989 to 1996, using the FiSAT software package of Gayanilo et al. (1996). Estimates of growth parameters are in general agreement with previous studies on the same species. Results also imply that the growth of Scomber japonicus slows down during the cold season by approximately 50% with respect to the average growth. The mean value of the power b is significantly larger than 3, indicating that the model of allometric growth should be used for the length-weight relationship and calculation of the condition factor.

Age and length composition of Columbia Basin chinook, sockeye, and coho salmon at Bonneville Dam in 2001

In 2001, representative samples of adult Columbia Basin chinook (Oncorhynchus tshawytscha), sockeye (O. nerka), and coho salmon (O. kisutch) populations at Bonneville Dam were collected. Fish were trapped, anesthetized, sampled for scales and biological data, revived, and then released adult migrating salmonids. Scales were examined to estimate age composition; the results contributed to an ongoing database for age class structure of Columbia Basin salmon populations. Based on scale analysis of chinook salmon, four-year-old fish (from brood year [BY] 1997) comprised 88% of the spring chinook, 67% of the summer chinook, and 42% of the Bright fall chinook salmon population. Five-year-old fish (BY 1996) comprised 9% of the spring chinook, 14% of the summer chinook, and 9% of the fall chinook salmon population. The sockeye salmon population at Bonneville was predominantly four-year-old fish (81%), with 18% returning as five-year-olds in 2001. The coho salmon population was 96% three-year-old fish (Age 1.1). Length analysis of the 2001 returns indicated that chinook salmon with a stream-type life history are larger (mean length) than the chinook salmon with an ocean-type life history. Trends in mean length over the sampling period for returning 2001 chinook salmon were analyzed. Chinook salmon of age classes 0.2 and 1.3 show a significant increase in mean length over time. Age classes 0.1, 0.3, 0.4, 1.1, 1.2, and 1.4 show no significant change over time. A year class regression over the past 12 years of data was used to predict spring, summer, and Bright fall chinook salmon population sizes for 2002. Based on three-year-old returns, the relationship predicts four-year-old returns of 132,600 (± 46,300, 90% predictive interval [PI]) spring chinook and 44,200 (± 11,700, 90% PI) summer chinook salmon for the 2002 runs. Based on four-year-old returns, the relationship predicts five-year-old returns of 87,800 (± 54,500, 90% PI) spring, 33,500 (± 11,500, 90% PI) summer, and 77,100 (± 25,800, 90% PI) Bright fall chinook salmon for the 2002 runs. The 2002 run size predictions should be used with caution; some of these predictions are well beyond the range of previously observed data.

Age and length composition of Columbia Basin chinook, sockeye, and coho salmon at Bonneville Dam in 2000

In 2000, representative samples of adult Columbia Basin chinook (Oncorhynchus tshawytscha), sockeye (O. nerka), and coho salmon (O. kisutch), populations were collected at Bonneville Dam. Fish were trapped, anesthetized, sampled for scales and biological data, allowed to revive, and then released. Scales were examined to estimate age composition and the results contribute to an ongoing database for age class structure of Columbia Basin salmon populations. Based on scale analysis, four-year-old fish (from brood year (BY) 1996) were estimated to comprise 83% of the spring chinook, 31% of the summer chinook, and 32% of the upriver bright fall chinook salmon population. Five-year-old fish (BY 1995) were estimated to comprise 2% of the spring chinook, 26% of the summer chinook, and 40% of the fall chinook salmon population. Three-year-old fish (BY 1997) were estimated to comprise 14% of the spring chinook, 42% of the summer chinook, and 17% of the fall chinook salmon population. Two-year-olds accounted for approximately 11% of the fall chinook population. The sockeye salmon population sampled at Bonneville was predominantly four-year-old fish (95%), and the coho salmon population was 99.9% three-year-old fish (Age 1.1). Length analysis of the 2000 returns indicated that chinook salmon with a stream-type life history are larger (mean length) than the chinook salmon with an ocean-type life history. Trends in mean length over the sampling period were also analysis for returning 2000 chinook salmon. Fish of age classes 0.2, 1.1, 1.2, and 1.3 have a significant increase in mean length over time. Age classes 0.3 and 0.4 have no significant change over time and age 0.1 chinook salmon had a significant decrease in mean length over time. A year class regression over the past 11 years of data was used to predict spring and summer chinook salmon population sizes for 2001. Based on three-year-old returns, the relationship predicts four-year-old returns of 325,000 (± 111,600, 90% Predictive Interval [PI]) spring chinook and 27,800 (± 29,750, 90% PI) summer chinook salmon. Based on four-year-old returns, the relationship predicts five-year-old returns of 54,300 (± 40,600, 90% PI) spring chinook and 11,000 (± 3,250, 90% PI) summer chinook salmon. The 2001 run size predictions used in this report should be used with caution, these predictions are well beyond the range of previously observed data.

Age and length composition of Columbia Basin chinook, sockeye, and coho salmon at Bonneville Dam in 2002

In 2002, representative samples of migrating Columbia Basin chinook (Oncorhynchus tshawytscha), sockeye (O. nerka), and coho salmon (O. kisutch) adult populations were collected at Bonneville Dam. Fish were trapped, anesthetized, sampled for scales and biological data, revived, and then released. Scales were examined to estimate age composition; the results contributed to an ongoing database for age class structure of Columbia Basin salmon populations. Based on scale analysis of chinook salmon, four-year-old fish (from brood year [BY] 1998) comprised 86% of the spring chinook, 51% of the summer chinook, and 51% of the bright fall chinook salmon population. Five-year-old fish (BY 1997) comprised 13% of the spring chinook, 43% of the summer chinook, and 11% of the bright fall chinook salmon population. The sockeye salmon population at Bonneville was predominantly five-year-old fish (55%), with 40% returning as four-year-olds in 2002. For the coho salmon population, 88% of the population was three-year-old fish of age class 1.1, while 12% were age class 1.0. Length analysis of the 2002 returns indicated that chinook salmon with a stream-type life history are larger (mean length) at age than the chinook salmon with an ocean-type life history. Trends in mean length over the sampling period for returning 2002 chinook salmon were analyzed. Chinook salmon of age classes 1.2 and 1.3 show a significant increase in mean length over the duration of the migration. A year class regression over the past 14 years of data was used to predict spring, summer, and bright fall chinook salmon population sizes for 2003. Based on three-year-old returns, the relationship predicts four-year-old returns of 54,200 (± 66,600, 90% predictive interval [PI]) spring chinook, 23,800 (± 19,100, 90% PI) summer, and 169,100 (± 139,500, 90% PI) bright fall chinook salmon for the 2003 runs. Based on four-year-old returns, the relationship predicts five-year-old returns of 36,300 (± 35,400, 90% PI) spring, 63,800 (± 10,300, 90% PI) summer, and 91,100 (± 69,400, 90% PI) bright fall chinook salmon for the 2003 runs. The 2003 run size predictions should be used with caution; some of these predictions are well beyond the range of previously observed data.

Morphometric relationship of Lingula larvae collected from the Arabian Sea

Morphometric studies were made on Lingula larvae collected from three different stations off Karwar and Coondapur. The data pertaining to length, breadth and the pairs of cirri were subjected to statistical analysis. The relationship between length and breadth shows allometric growth. The rate of increase in length in relation to breadth is not statistically significant up to the 10 P.C. stage. Increase in length is faster up to 12 P.C. stage.

Length-weight relationships and relative conditions of two sciaenids Otolithes cuvieri Trewavas and Johnius elongatus Mohan from the Karachi coast

Estimates of length-weight relationship in Otolithes cuvieri justify separate equations for males (log W =-5.0100+3.1365 log L) and females (log W =-5.2000+3.1006 log L). Relative condition factor "Kn" was found to be 0.877-1.946 in males and 0.879-1.328 in females. High "Kn" values during March to September at 180-220 mm TL in either sexes are indicative of the maturation of gonads. Separate equations for length-weight relationship are also justified for males (log W = -5.1126 + 3.0690 log L) and females (log W = -5.6400 + 3.3070 log L) of Johnius elongatus . "Kn" values were found to be 0.924-1.894 for males and 0.894-1.087 for females. High "Kn" values during January-May and August-September at 130 mm TL onward are indicative of gonadal maturation.

Length-weight studies of Epinephelus chlorostigma and E. areolatus from Arabian Gulf

Regression coefficient value (b) of the length-weight relation of Epinephelus chlorostigma was registered as 2.6383, which is significantly (p<0.01) less than the hypothetical value (3). This coefficient of E. areolatus was registered as 2.9500, a value close to 3. The correlation coefficients (r) were registered as 0.9725 and 0.9837 for E. chlorostigma and E. areolatus, respectively, which show a good relationship between the two parameters.

Studies on fecundity of Puntius sarana (Ham.) in relation to total length, total weight and ovary weight

A total of 43 mature female of Puntius sarana (Ham.) ranging from 204 mm to 320 mm in length and 102 to 482 g in weight were used for present studies. The relationship between fecundity with respect to total length (TL), total weight (TW) and ovary weight (OW) was found to be linear. The coefficient of co-relation 'r' of the above relationships was found to be 0.5947, 0.5761 and 0.9837 respectively. All these values are highly significant (P=0.01) indicating a close relationship between these parameters. However, as indicated by value of 'r' (0.9837), the fecundity is more closely related to ovary weight and hence the ovary weight may be a better index of fecundity than the total length or weight.

Studies on fecundity of Rita pavimentata (Gunther) in relation to total length, total weight and ovary weight

A total of thirty eight ripe ovaries from the specimens of Rita pavimentata, measuring 230 to 355 mm in total length (TL) and 250 to 750 g in total weight (TW), were selected to study the fecundity. The relationship between fecundity 'and total length (TL), total weight (TW) and ovary weight (OW) was found to be linear. The coefficient of co-relation 'r' of the above relationship was found to be 0.92, 0.94 and 0.96 respectively. All these values are highly significant (P=0.01) indicating a close relationship between compared parameters. However, as indicated by value of 'r' (0.96), the fecundity is more closely related to ovary weight and hence the ovary weight may be a better index of fecundity than the total body length or weight.