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Sea Snake (Lapemis hardwickii)

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The study examined the population structure and reproductive conditions of the marine snake Lapemis hardwickii along the west coast of Sabah from January to December 1987. A total of 754 snakes were collected, consisting of 363 males and 391 females. Females were found to be significantly heavier and longer than males. Nearly 95% of females caught from January to March were carrying large egg yolks, indicating synchronized mating patterns. Clutch size varied from 1 to 6 eggs, with three eggs being most common. The observations provide insights into the morphological differences and reproductive behaviors of L. hardwickii.

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Prepared by; SOB DIHA FARAH PREZ YOOB
BASIC INFORMATIONS Authors name : Han Kwai Hin, Robert B. Stuebing and Harold K. Voris. Articles title : Population Structure & Reproduction In The Marine Snake, Lapemis hardwickii Gray , From The West Coast Of Sabah. Journals title :The Sarawak Museum Journal (1991) .
ABSTRACT & INTRODUCTION
ABSTRACT SUMMARY The study was done in west coast of Sabah January to December 1987 No sexual dimorphism There is a maximal amount of energy to be invested into reproduction
CRITIQUE The parabolic relationship between egg weight and body weight of the females suggests that there is a maximal amount of energy to be invested into reproduction. Instead of suggest, they can use more convincing word such as shows/indicate. No keywords stated
INTRODUCTION SUMMARY Little is known about the sea snakes in Borneo Only Laticauda colubrina has been studied in Kalampunian Damit 10 species known from Sabah Purpose of this study examine population structure and variations in reproductive conditions of Lapemis hardwickii
SUGGESTIONS Can put the general information about the population structure and reproduction of sea snakes To provide basic information about sea snakes to readers
METHODOLOGY
754 specimens of Lapemis hardwickii Depth 25-30 m Frozen in ice Rethawed (soaking in water) Total length and tail length (mm)
Total length -tail length = snout-vent length Recorded the individual mass (gram) Sexing the snake (absence or presence of hemipenes) Male - squeeze posterior to anus Female - pair of genital openings
Examine reproductive structures Male -Measure left testes (mm) -Stores in 10% formalin -Processed with Tisumation (Fisher model) -Selected 35 specimens for histological analysis Female -Count yolky eggs (in oviducts) -Eggs found with embryos (separately regarded and determine the mass) -determine total length, tail length and snout-vent length of embryos -Isolated and weighed the wet fat
DATA ANALYSIS Students t-tests (examine snout-vent length, tail length and weight differences between the sexes) Regression (determine correlation) Male testis length and snout-vent length Female egg weight and body weight of the egg-bearing -mean yolk weight, and mean embryo of a clutch, -mean total length of embryos and mean embryo weight of a clutch
CRITIQUE Slightly confusing, did not mentioned male or female snakes.
RESULT
RESULTS Sample collected 363 males 391 females N= 754
MORPHOMETRIC VARIATION (RANGE) Total length = 364 972 mm Snout-vent length = 323 - 880 mm Tail length = 41 105 mm Body weight = 263.63.6 g
Females were significantly heavier and longer in snout-vent length than males. Females (277.0賊5.2 g, 653.6賊3.8 mm) Males (249.2賊5.0 g, 640.1賊4.0 mm) However, total length were not significantly different between two gender Females (727.3賊4.3 mm) Males (716.0賊0.4 mm) Mean tail length was significantly greater in males (76.6賊0.5) than females (74.1賊0.5)
REPRODUCTIVE CONDITION Ratio of adult male to female = 0.93 Ration of male/female embryos = 1.37 94.4%, female specimens caught found carrying large egg yolks from January to March. 47.5% of them have three eggs (clutch size varied from 1-6 eggs)
Proportion of gravid females was high during january(80%), February(92.3%) and March(95.1%) and dropped drastically form July(18.2) to October(2.6%). Frequency of twins = 2/64 Frequency of triplets= 1/64)
Comparison (Voris and Jayne method, 1979) of snout-vent length for clutches and clutch size suggest that: Growth rate = 95mm in 90 days, 1mm a day. Estimation of baby snakes birth weight = 39.7 g Total length = 373.4 mm From Figure 9, there are gradual increase in wet fat deposition in female throughout September to November and decrease in December.
CRITIQUE Results relevant to objectives. The morphometric variation data is to examine the population structure. Reproductive condition was also examined in the result. Overall result can be used.
Confusions during reading page 465, line 8 to 9. Table 1 shows the fluctuations of monthly sample size in which the number of snakes caught from January to September was three times as numerous as that from January to March . Writers idea could not easily reach readers.
Numerical mistake? Page 465, line 31 (263.63.6) g
DISCUSSIONS & CONCLUSION
What do the observations mean? Morphological differences between the sexes are not directly observable in Lapemis hardwickii. Supported by: Fig. 1, 2, and 3 Males have smaller body size, anhances in locating their mates for reproduction (Spellerberg, 1982). THE STRENGTH Each graph has a reliable interpretation of data from the result part. The interpretation of data seem to be supported by other research and cited in the study.
Reproductive condition. Supported by; Fig. 5-10. Found that 94.9% of female specimens caught from January to March carried large yolky eggs showing the possibility of synchronized mating patterns in female. This result met with Voris and Lemen (1981). The finding that male began producing sperm cells actively at a snout-vent length of 486mm agrees with Bergmans data (1949). 3. Comparison with other species. They are; Laticauda colubrina. Pelamis platurus. Enhydrina schistosa.
THE WEAKNESS 2. Undefined value - the value stated here has no relevance origin. 1. References with no date/year.
3. Authors with no date/year reference. 4. Legends of the graph is incomplete .
..the estimated total length at birth obtained in this study differs greatly from Bergmans estimation.. Whether such differences in estimation were due to interpopulation differences or methods used are not known. (pp. 473) The authors have no solution/idea on the problem raised. But from the methodology part, there was stated that; Specimens with tails partially severed were excluded from calculations of tail length and snout-vent length. (pp. 464) Besides, number of the excluded snakes is not stated.
OUR REFERENCES: Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003).Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site. Retrieved 30 September 2009, from http://www.uoguelph.ca/mcb/courses/MICR3260/research_lab/index. htm

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Sea Snake (Lapemis hardwickii)

  • 1. Prepared by; SOB DIHA FARAH PREZ YOOB
  • 2. BASIC INFORMATIONS Authors name : Han Kwai Hin, Robert B. Stuebing and Harold K. Voris. Articles title : Population Structure & Reproduction In The Marine Snake, Lapemis hardwickii Gray , From The West Coast Of Sabah. Journals title :The Sarawak Museum Journal (1991) .
  • 3. ABSTRACT & INTRODUCTION
  • 4. ABSTRACT SUMMARY The study was done in west coast of Sabah January to December 1987 No sexual dimorphism There is a maximal amount of energy to be invested into reproduction
  • 5. CRITIQUE The parabolic relationship between egg weight and body weight of the females suggests that there is a maximal amount of energy to be invested into reproduction. Instead of suggest, they can use more convincing word such as shows/indicate. No keywords stated
  • 6. INTRODUCTION SUMMARY Little is known about the sea snakes in Borneo Only Laticauda colubrina has been studied in Kalampunian Damit 10 species known from Sabah Purpose of this study examine population structure and variations in reproductive conditions of Lapemis hardwickii
  • 7. SUGGESTIONS Can put the general information about the population structure and reproduction of sea snakes To provide basic information about sea snakes to readers
  • 9. 754 specimens of Lapemis hardwickii Depth 25-30 m Frozen in ice Rethawed (soaking in water) Total length and tail length (mm)
  • 10. Total length -tail length = snout-vent length Recorded the individual mass (gram) Sexing the snake (absence or presence of hemipenes) Male - squeeze posterior to anus Female - pair of genital openings
  • 11. Examine reproductive structures Male -Measure left testes (mm) -Stores in 10% formalin -Processed with Tisumation (Fisher model) -Selected 35 specimens for histological analysis Female -Count yolky eggs (in oviducts) -Eggs found with embryos (separately regarded and determine the mass) -determine total length, tail length and snout-vent length of embryos -Isolated and weighed the wet fat
  • 12. DATA ANALYSIS Students t-tests (examine snout-vent length, tail length and weight differences between the sexes) Regression (determine correlation) Male testis length and snout-vent length Female egg weight and body weight of the egg-bearing -mean yolk weight, and mean embryo of a clutch, -mean total length of embryos and mean embryo weight of a clutch
  • 13. CRITIQUE Slightly confusing, did not mentioned male or female snakes.
  • 15. RESULTS Sample collected 363 males 391 females N= 754
  • 16. MORPHOMETRIC VARIATION (RANGE) Total length = 364 972 mm Snout-vent length = 323 - 880 mm Tail length = 41 105 mm Body weight = 263.63.6 g
  • 17. Females were significantly heavier and longer in snout-vent length than males. Females (277.0賊5.2 g, 653.6賊3.8 mm) Males (249.2賊5.0 g, 640.1賊4.0 mm) However, total length were not significantly different between two gender Females (727.3賊4.3 mm) Males (716.0賊0.4 mm) Mean tail length was significantly greater in males (76.6賊0.5) than females (74.1賊0.5)
  • 18. REPRODUCTIVE CONDITION Ratio of adult male to female = 0.93 Ration of male/female embryos = 1.37 94.4%, female specimens caught found carrying large egg yolks from January to March. 47.5% of them have three eggs (clutch size varied from 1-6 eggs)
  • 19. Proportion of gravid females was high during january(80%), February(92.3%) and March(95.1%) and dropped drastically form July(18.2) to October(2.6%). Frequency of twins = 2/64 Frequency of triplets= 1/64)
  • 20. Comparison (Voris and Jayne method, 1979) of snout-vent length for clutches and clutch size suggest that: Growth rate = 95mm in 90 days, 1mm a day. Estimation of baby snakes birth weight = 39.7 g Total length = 373.4 mm From Figure 9, there are gradual increase in wet fat deposition in female throughout September to November and decrease in December.
  • 21. CRITIQUE Results relevant to objectives. The morphometric variation data is to examine the population structure. Reproductive condition was also examined in the result. Overall result can be used.
  • 22. Confusions during reading page 465, line 8 to 9. Table 1 shows the fluctuations of monthly sample size in which the number of snakes caught from January to September was three times as numerous as that from January to March . Writers idea could not easily reach readers.
  • 23. Numerical mistake? Page 465, line 31 (263.63.6) g
  • 24. DISCUSSIONS & CONCLUSION
  • 25. What do the observations mean? Morphological differences between the sexes are not directly observable in Lapemis hardwickii. Supported by: Fig. 1, 2, and 3 Males have smaller body size, anhances in locating their mates for reproduction (Spellerberg, 1982). THE STRENGTH Each graph has a reliable interpretation of data from the result part. The interpretation of data seem to be supported by other research and cited in the study.
  • 26. Reproductive condition. Supported by; Fig. 5-10. Found that 94.9% of female specimens caught from January to March carried large yolky eggs showing the possibility of synchronized mating patterns in female. This result met with Voris and Lemen (1981). The finding that male began producing sperm cells actively at a snout-vent length of 486mm agrees with Bergmans data (1949). 3. Comparison with other species. They are; Laticauda colubrina. Pelamis platurus. Enhydrina schistosa.
  • 27. THE WEAKNESS 2. Undefined value - the value stated here has no relevance origin. 1. References with no date/year.
  • 28. 3. Authors with no date/year reference. 4. Legends of the graph is incomplete .
  • 29. ..the estimated total length at birth obtained in this study differs greatly from Bergmans estimation.. Whether such differences in estimation were due to interpopulation differences or methods used are not known. (pp. 473) The authors have no solution/idea on the problem raised. But from the methodology part, there was stated that; Specimens with tails partially severed were excluded from calculations of tail length and snout-vent length. (pp. 464) Besides, number of the excluded snakes is not stated.
  • 30. OUR REFERENCES: Kuyper, B.J. (1991). Bringing up scientists in the art of critiquing research. Bioscience 41(4), 248-250. Wood, J.M. (2003).Research Lab Guide. MICR*3260 Microbial Adaptation and Development Web Site. Retrieved 30 September 2009, from http://www.uoguelph.ca/mcb/courses/MICR3260/research_lab/index. htm