Gerald Quinitio - Academia.edu (original) (raw)

Papers by Gerald Quinitio

Contribution No. 89 of the Aquaculture Department, SEAFDEC.The survival and growth of milkfish (C... more Contribution No. 89 of the Aquaculture Department, SEAFDEC.The survival and growth of milkfish (Chanos chanos ) fry stored in plastic basins at different salinity levels and stock manipulation methods without aeration and fed with hard-boiled chicken egg yolk over a period of 14 days were determined. Results showed that survival rate and increase in body weight did not differ significantly (P > .05) at different salinity levels nor with different stock manipulation methods. Moreover, there was no evidence of a significant interaction between salinity and stock manipulation method. The highest survival rate was 97.8% with stock manipulation 1 and 8 ppt salinity, while the lowest was 95.% with stock manipulation 1 at 32 ppt salinity. Results indicated that there was no need to reduce the salintiy of water used in storing fry in order to obtain higher survival rates as commonly believed. Sufficient food and maintenance of good water quality appeared to be more important than salinity for higher survival of fry during storage

Light and electron microscopic investigation were conducted on the spermatogenic cell in the test... more Light and electron microscopic investigation were conducted on the spermatogenic cell in the testis of the freshwater sculpin, Cottus nozawae. Light microscopic examination showed that two types of spermatids, normal and aberrant, qxisted in the seminal lobule during the regular testicular activity. Both spermaids were mononucleate but the aberrant spermatids ha mor basophilic nucleus than the normal. Aberrant spermatids enlarged and were than released into lumen of the seminal lobules. Ultrastucturally, highly electron-bense granules occurred in the nuclear chromatin of aberrant spermatids. These increased in size becoming the core of chromatin globules which then filled the enlargeed nucleus. The aberrant spermatids when released into the lobule lumen underwent further degeneration

Cover page, title page and table of content

Transport of live fish is a routine activity in aquaculture. Various transport techniques have be... more Transport of live fish is a routine activity in aquaculture. Various transport techniques have been reported by Berka. Transport of grouper eggs (Epinephelus suillus) between fisheries stations in Thailand is being conducted. However, no report has been made on transport of yolk-sac larvae of this fish. In the Philippines transport of eggs poses difficulties, particularly for hatcheries which are distant from the broodstock rearing site since spawning occurs between 1600 and 1800 h. Eggs can only be collected the following morning and hatching starts around 1200-1300 h (20 h after fertilization). Thus it seems advisable to transport yolk-sac larvae rather than eggs of grouper under such conditions. This study was conducted to determine the feasibility and optimum loading density of transporting grouper yolk-sac larvae for about 2 h

Gonad development of rabbitfish Siganus guttatus from an oil spill affected (Taklong Island) and ... more Gonad development of rabbitfish Siganus guttatus from an oil spill affected (Taklong Island) and unaffected (Ave Maria Sanctuary) area in Guimaras province were monitored from November 2007 to December 2008. There were instances wherein samples could not be collected in both sites at the same period since tidal change was not abrupt so that the fish did not migrate to the seagrass bed where they fed and eventually get caught in the barrier net. Male rabbitfishes sampled from both area had 23-400 g body weight (BW) and 6.15-29.00 cm total length (TL) while females had 25-753 g BW and 6.50-31 cm TL. The fish were dissected and gonads

A study was conducted to determine the effects of single injections of human chorionic gonadotrop... more A study was conducted to determine the effects of single injections of human chorionic gonadotropin (HCG) and Durandron Forte 250 on sperm motility, vitality and density and also on the consistency of milt in newly caught, wild, mature milkfish (Chanos chanos). In contrast to HCG, single injections of Durandron Forte 250 were effective not only in inducing spermiation but also in maintaining newly caught mature males in good running condition for a maximum of 7 days, despite daily handling and collection of approximately 3ml milt.

Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enrich... more Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enriched fish by catch (TFC), and commercial HUFA A-enriched fish by catch (TFS) was monitored. Monthly egg production, spawning frequency, fertilization rate, egg viability, and hatching rates of the control were significantly higher compared to TFS Egg production. Spawning frequency and hatching rate of TC and TFS were not significantly different. Results suggest that varying the species of fish by catch could provide the requirements of E. Coioides broodstock so as to provide quality eggs

Aquaculture

... 45 Acknowledgement This study was supported by the Oil Spill Response of UP Visayas. We also ... more ... 45 Acknowledgement This study was supported by the Oil Spill Response of UP Visayas. We also extend our gratitude to Joey Arboleda, Mer-lan Lanusga and Conrado Manglal-lan for the help they ex-tended during the conduct of this study. ...

The Philippine Journal of Fisheries

Growth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off A... more Growth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off Antique province, Philippines, were investigated based on the length-frequency data collected from April 2019 until March 2020. Using the FISAT-II software, D. macrosoma growth parameters were computed as follows: L∞ = 26.18 cm TL, K = 1.00 yr-1, ø' = 2.836 yr-1, and an estimated life span of 3 years. Mortality values were estimated as: total mortality (Z) = 4.66 yr-1; natural mortality (M) = 1.88 yr-1; and fishing mortality (F) = 2.78 yr-1. The exploitation rate (E) was computed as 0.60 while Emax was 0.42 yr-1. The length at first capture Lc/L50 was estimated at 11.96 cm TL. There were two recruitment events in one year: July and December. D. macrosoma in Antique was growing isometrically and in good condition with the relative condition factor (Kn) values ranging from 0.99 to 3.39. The computed exploitation rate suggested that D. macrosoma faces a high level of exploitation in Anti...

Possible application of mibolerone for induced

This paper summarizes the results of the experiments on the induced breeding and larval rearing o... more This paper summarizes the results of the experiments on the induced breeding and larval rearing of milkfish (Chanos chanos) during the 1979 season. Milkfish larvae could be reared successfully without the use of trochophore larvae of oysters as feed during the first few days. In order to induce the ovulation of wild adult milkfish a higher dose of human chorionic gonadotropin hormone is required.

Results of the study indicate that the survival rate and increase in body weight did not differ s... more Results of the study indicate that the survival rate and increase in body weight did not differ significantly at different salinity levels or at different stocking density manipulation methods. A significant interaction between salinity and stocking density manipulation could not be demonstrated statistically. There apparently is no need to reduce the salinity of the water used in storing milkfish Chanos chanos fry in order to attain higher survival as commonly believed. Sufficient food and maintenance of good water quality are more important than salinity for higher survival of fry during storage.

The acute toxicity of dispersant Mardeus-455 added to water accommodated fractions (WAF) were eva... more The acute toxicity of dispersant Mardeus-455 added to water accommodated fractions (WAF) were evaluated in Gold-saddle rabbitfish Siganus guttatus fry after 72 h exposure under laboratory conditions. Mortalities of fry exposed to different concentrations of dispersed oil were recorded every hour for the first 6 h, every 3 h for the next 12 h, and every 6 h thereafter. Results showed that the higher the ratio of dispersant and WAF, the higher the mortality of the rabbitfish fry which may be due to the enhanced availability of polyaromatic hydrocarbons (PAH). The LC50 was computed at 3.692% of the oil volume. The application of dispersant in cleaning oil spills must be limited to reduce its harmful effect in the marine environment. Assessing toxicity of dispersed oil in fish fry may help understand the extent of environmental damage after cleaning oil spill using dispersant.

The shell is the most conspicuous and variable part of a bivalve and is largely affected by envir... more The shell is the most conspicuous and variable part of a bivalve and is largely affected by environmental conditions. Thus, this study was conducted to describe the changes in the shell shape of the horse mussel Modiolus metcalfei from Dumangas, Iloilo. Allometric changes in shape, sex-induced shape differences, and asymmetry were investigated using geometric morphometric methods. A total of 12 landmarks where used to obtain biological shape information from 60 horse mussel individuals. Multivariate analysis of variance revealed significant differences of shell shapes between sexes (Wilk’s λ=0.01, p=1.26E-219). Generally, males have an expanded shell but compressed mid-shell region while females have compressed shell but expanded midand postero-ventral region. Moreover, the multivariate regression of shape on centroid size was statistically significant (p<0.001, Goodall’s F-test). Smaller individuals were slender and elongate while larger individuals were slightly rounded and cur...

Asian Fisheries Science, 2006

This paper presents the results of a financial analysis of the aquaculture of Cromileptes altivel... more This paper presents the results of a financial analysis of the aquaculture of Cromileptes altivelis (mouse grouper, barramundi cod, polka dot or high-finned grouper) in Indonesia. The analysis provided financial information on individual broodstock, hatchery/nursery, and grow-out stages. The findings of the analysis indicate that, based on the assumptions, all three scenarios are financially feasible. However, the capital requirements for the broodstock and hatchery/nursery may be beyond the financial means of many small producers. These stages of grouper culture may need to be developed as a larger project by private investors or government. The capital investment requirements for grow-out (not including purchase of transport boxes) is within the financial means of small producers. Loans or other incentives will need to be made available for the small producer, but the cash flow indicates that these loans can be repaid in the first year of production.

Asian Fisheries Science, 2020

The exploitation of horse mussels Modiolus metcalfei (Hanley, 1843) in Dumangas, Iloilo has been ... more The exploitation of horse mussels Modiolus metcalfei (Hanley, 1843) in Dumangas, Iloilo has been going on for decades, yet effective fisheries management remains hindered by the poor understanding of the fishery. A value chain analysis was conducted to provide a better understanding of the horse mussel fishery in the area and identify upgrading strategies. Mapping of the value chain used data gathered through fisherfolk interviews, key informant interviews, and field observations. The collectors, processors, retailers, and ambulant vendors are the key players in the fishery. It is a sphere of both men and women who create value additions along the chain. While both men and women may engage in marketing, the majority of men are involved in the collection while women do the processing. The collectorcum-ambulant vendor benefits the most with a monthly income of PHP10,892.78 (USD217.86) with value addition of PHP8.30 kg-1 (USD0.17), followed by the collector with a monthly income of PHP9,597.46 (USD191.95) with a value addition of PHP4.00 kg-1 (USD0.08) and retailer with a monthly income of PHP5,000.00 (USD100.00) with value addition of PHP4.55 kg-1 (USD0.09). The actor who benefits the least in this value chain is the processor with a monthly income of PHP4,185.10 (USD83.70) with value addition of PHP2.30 kg-1 (USD0.05). Upgrading strategies at every node of the value chain along with its enabling strategies were proposed to improve the income of key actors and maximise the economic benefits from the horse mussel fishery.

Ocean & Coastal Management, 2018

With New Washington-Batan estuary as study site, this study determined the impact of Typhoon Haiy... more With New Washington-Batan estuary as study site, this study determined the impact of Typhoon Haiyan on capture fisheries through data that were collected before and after the typhoon event. To validate these results and to determine other related information (e.g., recovery of fishing after typhoon), key interviews and focus group discussions were conducted. The immediate impact of the typhoon event was disruption of fishing livelihood due to damage of fishing gears as about 94% of stationary fishing gears had considerable damage. Resumption of fishing operations varied largely among fishers depending on the degree of gear damage. Reconstruction of damaged stationary gears was hampered mainly by the financial capacity of fishers and the acute supply of bamboo which is the main component in the construction of these fishing gears. We also discuss typhoon impacts on other fishing gears such as line fishing, gillnets, and pots. These information are valuable in understanding impacts of extreme weather events on tropical small-scale fisheries so that managers may be able to devise measures to reduce vulnerabilities among coastal resource users.

Contribution No. 89 of the Aquaculture Department, SEAFDEC.The survival and growth of milkfish (C... more Contribution No. 89 of the Aquaculture Department, SEAFDEC.The survival and growth of milkfish (Chanos chanos ) fry stored in plastic basins at different salinity levels and stock manipulation methods without aeration and fed with hard-boiled chicken egg yolk over a period of 14 days were determined. Results showed that survival rate and increase in body weight did not differ significantly (P > .05) at different salinity levels nor with different stock manipulation methods. Moreover, there was no evidence of a significant interaction between salinity and stock manipulation method. The highest survival rate was 97.8% with stock manipulation 1 and 8 ppt salinity, while the lowest was 95.% with stock manipulation 1 at 32 ppt salinity. Results indicated that there was no need to reduce the salintiy of water used in storing fry in order to obtain higher survival rates as commonly believed. Sufficient food and maintenance of good water quality appeared to be more important than salinity for higher survival of fry during storage

Light and electron microscopic investigation were conducted on the spermatogenic cell in the test... more Light and electron microscopic investigation were conducted on the spermatogenic cell in the testis of the freshwater sculpin, Cottus nozawae. Light microscopic examination showed that two types of spermatids, normal and aberrant, qxisted in the seminal lobule during the regular testicular activity. Both spermaids were mononucleate but the aberrant spermatids ha mor basophilic nucleus than the normal. Aberrant spermatids enlarged and were than released into lumen of the seminal lobules. Ultrastucturally, highly electron-bense granules occurred in the nuclear chromatin of aberrant spermatids. These increased in size becoming the core of chromatin globules which then filled the enlargeed nucleus. The aberrant spermatids when released into the lobule lumen underwent further degeneration

Cover page, title page and table of content

Transport of live fish is a routine activity in aquaculture. Various transport techniques have be... more Transport of live fish is a routine activity in aquaculture. Various transport techniques have been reported by Berka. Transport of grouper eggs (Epinephelus suillus) between fisheries stations in Thailand is being conducted. However, no report has been made on transport of yolk-sac larvae of this fish. In the Philippines transport of eggs poses difficulties, particularly for hatcheries which are distant from the broodstock rearing site since spawning occurs between 1600 and 1800 h. Eggs can only be collected the following morning and hatching starts around 1200-1300 h (20 h after fertilization). Thus it seems advisable to transport yolk-sac larvae rather than eggs of grouper under such conditions. This study was conducted to determine the feasibility and optimum loading density of transporting grouper yolk-sac larvae for about 2 h

Gonad development of rabbitfish Siganus guttatus from an oil spill affected (Taklong Island) and ... more Gonad development of rabbitfish Siganus guttatus from an oil spill affected (Taklong Island) and unaffected (Ave Maria Sanctuary) area in Guimaras province were monitored from November 2007 to December 2008. There were instances wherein samples could not be collected in both sites at the same period since tidal change was not abrupt so that the fish did not migrate to the seagrass bed where they fed and eventually get caught in the barrier net. Male rabbitfishes sampled from both area had 23-400 g body weight (BW) and 6.15-29.00 cm total length (TL) while females had 25-753 g BW and 6.50-31 cm TL. The fish were dissected and gonads

A study was conducted to determine the effects of single injections of human chorionic gonadotrop... more A study was conducted to determine the effects of single injections of human chorionic gonadotropin (HCG) and Durandron Forte 250 on sperm motility, vitality and density and also on the consistency of milt in newly caught, wild, mature milkfish (Chanos chanos). In contrast to HCG, single injections of Durandron Forte 250 were effective not only in inducing spermiation but also in maintaining newly caught mature males in good running condition for a maximum of 7 days, despite daily handling and collection of approximately 3ml milt.

Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enrich... more Quality of eggs spawned by Epinephelus coioides fed fish by catch (control). Cod liver oil-enriched fish by catch (TFC), and commercial HUFA A-enriched fish by catch (TFS) was monitored. Monthly egg production, spawning frequency, fertilization rate, egg viability, and hatching rates of the control were significantly higher compared to TFS Egg production. Spawning frequency and hatching rate of TC and TFS were not significantly different. Results suggest that varying the species of fish by catch could provide the requirements of E. Coioides broodstock so as to provide quality eggs

Aquaculture

... 45 Acknowledgement This study was supported by the Oil Spill Response of UP Visayas. We also ... more ... 45 Acknowledgement This study was supported by the Oil Spill Response of UP Visayas. We also extend our gratitude to Joey Arboleda, Mer-lan Lanusga and Conrado Manglal-lan for the help they ex-tended during the conduct of this study. ...

The Philippine Journal of Fisheries

Growth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off A... more Growth, mortality, exploitation rate, and recruitment of Decapterus macrosoma in the waters off Antique province, Philippines, were investigated based on the length-frequency data collected from April 2019 until March 2020. Using the FISAT-II software, D. macrosoma growth parameters were computed as follows: L∞ = 26.18 cm TL, K = 1.00 yr-1, ø' = 2.836 yr-1, and an estimated life span of 3 years. Mortality values were estimated as: total mortality (Z) = 4.66 yr-1; natural mortality (M) = 1.88 yr-1; and fishing mortality (F) = 2.78 yr-1. The exploitation rate (E) was computed as 0.60 while Emax was 0.42 yr-1. The length at first capture Lc/L50 was estimated at 11.96 cm TL. There were two recruitment events in one year: July and December. D. macrosoma in Antique was growing isometrically and in good condition with the relative condition factor (Kn) values ranging from 0.99 to 3.39. The computed exploitation rate suggested that D. macrosoma faces a high level of exploitation in Anti...

Possible application of mibolerone for induced

This paper summarizes the results of the experiments on the induced breeding and larval rearing o... more This paper summarizes the results of the experiments on the induced breeding and larval rearing of milkfish (Chanos chanos) during the 1979 season. Milkfish larvae could be reared successfully without the use of trochophore larvae of oysters as feed during the first few days. In order to induce the ovulation of wild adult milkfish a higher dose of human chorionic gonadotropin hormone is required.

Results of the study indicate that the survival rate and increase in body weight did not differ s... more Results of the study indicate that the survival rate and increase in body weight did not differ significantly at different salinity levels or at different stocking density manipulation methods. A significant interaction between salinity and stocking density manipulation could not be demonstrated statistically. There apparently is no need to reduce the salinity of the water used in storing milkfish Chanos chanos fry in order to attain higher survival as commonly believed. Sufficient food and maintenance of good water quality are more important than salinity for higher survival of fry during storage.

The acute toxicity of dispersant Mardeus-455 added to water accommodated fractions (WAF) were eva... more The acute toxicity of dispersant Mardeus-455 added to water accommodated fractions (WAF) were evaluated in Gold-saddle rabbitfish Siganus guttatus fry after 72 h exposure under laboratory conditions. Mortalities of fry exposed to different concentrations of dispersed oil were recorded every hour for the first 6 h, every 3 h for the next 12 h, and every 6 h thereafter. Results showed that the higher the ratio of dispersant and WAF, the higher the mortality of the rabbitfish fry which may be due to the enhanced availability of polyaromatic hydrocarbons (PAH). The LC50 was computed at 3.692% of the oil volume. The application of dispersant in cleaning oil spills must be limited to reduce its harmful effect in the marine environment. Assessing toxicity of dispersed oil in fish fry may help understand the extent of environmental damage after cleaning oil spill using dispersant.

The shell is the most conspicuous and variable part of a bivalve and is largely affected by envir... more The shell is the most conspicuous and variable part of a bivalve and is largely affected by environmental conditions. Thus, this study was conducted to describe the changes in the shell shape of the horse mussel Modiolus metcalfei from Dumangas, Iloilo. Allometric changes in shape, sex-induced shape differences, and asymmetry were investigated using geometric morphometric methods. A total of 12 landmarks where used to obtain biological shape information from 60 horse mussel individuals. Multivariate analysis of variance revealed significant differences of shell shapes between sexes (Wilk’s λ=0.01, p=1.26E-219). Generally, males have an expanded shell but compressed mid-shell region while females have compressed shell but expanded midand postero-ventral region. Moreover, the multivariate regression of shape on centroid size was statistically significant (p<0.001, Goodall’s F-test). Smaller individuals were slender and elongate while larger individuals were slightly rounded and cur...

Asian Fisheries Science, 2006

This paper presents the results of a financial analysis of the aquaculture of Cromileptes altivel... more This paper presents the results of a financial analysis of the aquaculture of Cromileptes altivelis (mouse grouper, barramundi cod, polka dot or high-finned grouper) in Indonesia. The analysis provided financial information on individual broodstock, hatchery/nursery, and grow-out stages. The findings of the analysis indicate that, based on the assumptions, all three scenarios are financially feasible. However, the capital requirements for the broodstock and hatchery/nursery may be beyond the financial means of many small producers. These stages of grouper culture may need to be developed as a larger project by private investors or government. The capital investment requirements for grow-out (not including purchase of transport boxes) is within the financial means of small producers. Loans or other incentives will need to be made available for the small producer, but the cash flow indicates that these loans can be repaid in the first year of production.

Asian Fisheries Science, 2020

The exploitation of horse mussels Modiolus metcalfei (Hanley, 1843) in Dumangas, Iloilo has been ... more The exploitation of horse mussels Modiolus metcalfei (Hanley, 1843) in Dumangas, Iloilo has been going on for decades, yet effective fisheries management remains hindered by the poor understanding of the fishery. A value chain analysis was conducted to provide a better understanding of the horse mussel fishery in the area and identify upgrading strategies. Mapping of the value chain used data gathered through fisherfolk interviews, key informant interviews, and field observations. The collectors, processors, retailers, and ambulant vendors are the key players in the fishery. It is a sphere of both men and women who create value additions along the chain. While both men and women may engage in marketing, the majority of men are involved in the collection while women do the processing. The collectorcum-ambulant vendor benefits the most with a monthly income of PHP10,892.78 (USD217.86) with value addition of PHP8.30 kg-1 (USD0.17), followed by the collector with a monthly income of PHP9,597.46 (USD191.95) with a value addition of PHP4.00 kg-1 (USD0.08) and retailer with a monthly income of PHP5,000.00 (USD100.00) with value addition of PHP4.55 kg-1 (USD0.09). The actor who benefits the least in this value chain is the processor with a monthly income of PHP4,185.10 (USD83.70) with value addition of PHP2.30 kg-1 (USD0.05). Upgrading strategies at every node of the value chain along with its enabling strategies were proposed to improve the income of key actors and maximise the economic benefits from the horse mussel fishery.

Ocean & Coastal Management, 2018

With New Washington-Batan estuary as study site, this study determined the impact of Typhoon Haiy... more With New Washington-Batan estuary as study site, this study determined the impact of Typhoon Haiyan on capture fisheries through data that were collected before and after the typhoon event. To validate these results and to determine other related information (e.g., recovery of fishing after typhoon), key interviews and focus group discussions were conducted. The immediate impact of the typhoon event was disruption of fishing livelihood due to damage of fishing gears as about 94% of stationary fishing gears had considerable damage. Resumption of fishing operations varied largely among fishers depending on the degree of gear damage. Reconstruction of damaged stationary gears was hampered mainly by the financial capacity of fishers and the acute supply of bamboo which is the main component in the construction of these fishing gears. We also discuss typhoon impacts on other fishing gears such as line fishing, gillnets, and pots. These information are valuable in understanding impacts of extreme weather events on tropical small-scale fisheries so that managers may be able to devise measures to reduce vulnerabilities among coastal resource users.