scholarly journals Use of the term harvest when referring to wild stock exploitation

2020 ◽  
Vol 119 (1) ◽  
pp. 1-2
Author(s):  
James A. Bohnsack ◽  
Laura Jay W. Grove ◽  
Joseph E. Serafy
Keyword(s):  
2019 ◽  
Vol 14 (1) ◽  
pp. 19
Author(s):  
I Nyoman Adiasmara Giri ◽  
Sari Budi Moria Sembiring ◽  
Gigih Setia Wibawa ◽  
Haryanti Haryanti

Teripang pasir, Holothuria scabra merupakan salah satu komoditas perikanan yang mempunyai nilai ekonomi tinggi di Asia. Populasinya di alam semakin menurun karena aktivitas penangkapan secara berlebihan. Untuk mengantisipasi menurunnya stok teripang di alam, maka perlu segera dilakukan pengembangannya melalui kegiatan budidaya. Di samping ketersediaan benih, pakan merupakan salah satu faktor yang sangat menentukan keberhasilan budidaya teripang. Penelitian ini bertujuan mendapatkan formulasi pakan buatan yang tepat untuk mendukung pertumbuhan teripang pasir. Empat pakan percobaan dengan formula berbeda, sebagai perlakuan, dibuat dalam bentuk pelet kering. Pakan diformulasi menggunakan tepung Sargassum sp., tepung Ulva sp., tepung Gracilaria sp., yang dikombinasi dengan tepung kedelai dan tepung beras dengan proporsi berbeda. Pada percobaan-1, benih teripang (hasil pembenihan) ukuran 14,4 ± 6,5 g ditebar dalam delapan buah bak berukuran 2 m x 1 m x 0,6 m dengan kepadatan 100 ekor/bak. Teripang diberi pakan percobaan dengan frekuensi satu kali sehari selama lima bulan. Pada percobaan-2, benih teripang ukuran 7,0 ± 1,6 g ditebar dalam delapan buah keramba jaring apung berukuran 1 m x 1 m x 1 m yang diletakkan di tambak dengan kepadatan 50 ekor per jaring. Teripang diberi pakan percobaan dengan frekuensi satu kali sehari selama empat bulan. Hasil percobaan menunjukkan pakan buatan yang diformulasi menggunakan tepung Sargassum sp., tepung Ulva sp., tepung kedelai, dan tepung beras dapat mendukung pertumbuhan dan sintasan teripang pasir, baik yang dipelihara dalam bak maupun dalam jaring apung di tambak. Sintasan teripang tidak dipengaruhi oleh pakan percobaan (P>0,05). Pakan buatan dengan komposisi bahan 30% tepung Sargassum sp., 35% tepung Ulva sp., 4% tepung kedelai, dan 18% tepung beras menghasilkan pertumbuhan terbaik dan dapat diaplikasikan pada pemeliharaan teripang pasir.Sandfish, Holothuria scabra is a highly valued sea cucumber product in Asian markets. Current exploitation has reduced its wild stock to an alarming level. In order to alleviate the over-exploitation to its wild population and provide a reliable supply of market demands, the aquaculture technology of sandfish has to be developed and perfected. Feed is one of the important factors for a successful sea cucumber aquaculture, besides seed supply. The aim of this experiment was to obtain an appropriate feed formulation to support the growth of sandfish. Four experimental diets (dry pellet) were formulated using seaweed meal of Sargassum, Ulva, and Gracilaria, combined with soybean meal and rice flour, each with different proportions. In experiment-1, cultured sandfish juveniles with an initial weight of 14.4 ± 6.5 g were stocked into eight concrete tanks (2 m x 1 m x 0.6 m) with a density of 100 juveniles/tank. In experiment-2, sandfish juveniles with an initial weight of 7.0 ± 1.6 g were stocked into eight floating net cages (1 m x 1 m x 1 m) erected in a pond with a density of 50 juveniles/cage. The sandfish juveniles were fed once daily with the experimental diets for five and four months for experiment-1 and experiment-2, respectively. Results of the experiment showed that diet formulated with Sargassum, Ulva, and soybean meals and rice flour produced good growth and survival of sandfish, both reared in concrete tanks and in floating net cages. The experimental diets did not affect the survival of sandfish (P>0.05). Formulated diet containing 30% Sargassum meal, 35% Ulva meal, 4% soybean meal, 18% rice flour, and 6% ‘lap lap’ flour gave the best growth and could be applied for grow-out of sandfish.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Amanda J Frazier ◽  
Nathan R Jensen ◽  
Shawn P Young ◽  
Anne E Todgham

Abstract The practice of mitigating cannibalism in aquaculture is an important focus for hatcheries seeking to maximize yield and has been maintained in hatcheries focusing on wild stock restoration. We hypothesize, however, that a cannibal feeding strategy may confer performance advantages over a non-cannibal feeding strategy and that perhaps cannibal size grading may not be optimal for hatcheries focusing on conservation goals. This study examined metabolic performance differences between cannibal and non-cannibal burbot, Lota lota maculosa, at the Kootenai Tribe of Idaho Twin Rivers Hatchery in Moyie Springs, ID, USA. After habitat alteration led to functional extinction of burbot in the region, the Twin Rivers Hatchery has played a leading role in the reestablishment of burbot in the Kootenai River, ID, and British Columbia. We examined morphometric data (weight, length and condition factor), whole animal resting metabolic rate and the enzyme activity of lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase to describe the baseline metabolic performance of cannibal and non-cannibal burbot. Taken together, our results demonstrated significant differences in the metabolic strategies of cannibal vs. non-cannibal burbot, where cannibals relied more heavily on carbohydrate metabolism and non-cannibals relied more heavily on glycolytic and lipid metabolism. This study demonstrates the need to reevaluate the traditional practice of removing cannibal fish in conservation hatcheries, as it may not be the ideal strategy of raising the most robust individuals for release. When natural habitat conditions cannot be restored due to permanent habitat alteration, prioritizing release of higher performing individuals could help achieve conservation goals.


2020 ◽  
Vol 8 (6) ◽  
pp. 471
Author(s):  
Nguyen Thanh Vu ◽  
Tran Thi Thuy Ha ◽  
Vo Thi Bich Thuy ◽  
Vu Thi Trang ◽  
Nguyen Hong Nguyen

The striped catfish Pangasianodon hypophthalmus is an important freshwater fish cultured in many countries where the collection of wild brooders is still widely practiced. Global farming development of this species makes use of significant natural resources that pose challenges for the genetic diversity of striped catfish. Hence, this study aims to conduct a systematic genetic diversity assessment of wild and farmed catfish stocks collected from four major pangasius-farming countries, using a new genotyping by sequencing platform known as DArT-seq technology. Our population genomic analyses using 7263 single-nucleotide polymorphisms (SNPs) after high-quality-control showed that there were two distinct populations of striped catfish in the lower Mekong river: (i) wild catfish from Thailand and (ii) catfish from Cambodia and Vietnam. The genetic diversity was greatest (0.363) in the wild stock from Thailand, but it was lower in farmed and wild stocks in other countries (0.049 to 0.088). The wild stocks were more genetically diverse than the farmed animals (0.103 vs. 0.064). The inbreeding coefficient ranged from 0.004 and 0.109, with the lowest value (−0.499) in the wild animals from Thailand. Molecular inference methods revealed high degree of historical effective population size (1043.9–1258.4), but there was considerable decline in the contemporary estimates in all populations (10.8 to 73.6). Our additional analyses calculating divergent times and migration patterns showed that the wild catfish from Thailand stand out as separate lineages, while those from Cambodia and Vietnam are genetically identical. Our results also indicated that the cultured stock in Bangladesh originated from the lower part of the Mekong river. These findings have significant practical implications in the context of genetic selection and conservation of striped catfish in the region. Collectively, they will contribute to the sustainable development of the striped catfish sector in these countries.


1920 ◽  
Vol 2 (5) ◽  
pp. 445-464 ◽  
Author(s):  
Joseph Krafka

Three strains of the bar-eyed mutant of Drosophila melanogaster Meig have been reared at constant temperatures over a range of 15–31°C. The mean facet number in the bar-eyed mutant varies inversely with the temperature at which the larvæ develop. The temperature coefficient (Q10) is of the same order as that for chemical reactions. The facet-temperature relations may be plotted as an exponential curve for temperatures from 15–31°. The rate of development of the immature stages gives a straight line temperature curve between 15 and 29°. Beyond 29° the rate decreases again with a further rise in temperature. The facet curve may be readily superimposed on the development curve between 15 and 27°. The straight line feature of the development curve is probably due to the flattening out of an exponential curve by secondary factors. Since both the straight line and the exponential curve appear simultaneously in the same living material, it is impractical to locate the secondary factors in enzyme destruction, differences in viscosity, or in the physical state of colloids. Differential temperature coefficients for the various separate processes involved in development furnish the best basis for an explanation of the straight line feature of the curve representing the effect of temperature on the rate of physiological processes. Facet number in the full-eyed wild stock is not affected by temperature to a marked degree. The mean facet number for fifteen full-eyed females raised at 27° is 859.06. The mean facet number for the Low Selected Bar females at 27° is 55.13; for the Ultra-bar females at 27° it is 21.27. A consistent sexual difference appears in all the bar stocks, the females having fewer facets. This relation may be expressed by the sex coefficient, the average value of which is 0.791. The average observed difference in mean facet number for a difference of 1°C. in the environment in which the flies developed is 3.09 for the Ultra-bar stock and 14.01 for the Low Selected stock. The average proportional differences in the mean for a difference of 1°C. are 9.22 per cent for Ultra-bar, and 14.51 for Low Selected. The differences in the number of facets per °C. are greatest at the low and least at the high temperatures. The difference in the number of facets per °C. varies with the mean. The proportional differences in the mean per °C. are greatest at the lower (15–17.5°) and higher (29–31°) temperatures and least at the intermediate temperatures. Temperature is a factor in determining facet number only during a relatively short period in larval development. This effective period, at 27°, comes between the end of the 3rd and the end of the 4th day. At 15°, this period is initiated at the end of 8 days following a 1st day at 27°. At 27° this period is approximately 18 hours long. At 15° it is approximately 72 hours long. The number of facets and the length of the immature stage (egg-larval-pupal) appear related when the whole of development is passed at one temperature. That the number of facets is not dependent upon the length of the immature stage is shown by experiments in which only a part of development was passed at one temperature and the remainder at another. Temperature affects the reaction determining the number of facets in approximately the same way that it affects the other developmental reactions, hence the apparent correlation between facet number and the length of the immature stage. Variability as expressed by the coefficient of variability has a tendency to increase with temperature. Standard deviation, on the other hand, appears to decrease with rise in temperature. Neither inheritance nor induction effects are exhibited by this material. This study shows that environment may markedly affect the somatic expression of one Mendelian factor (bar eye), while it has no visible influence on another (white eye).


1985 ◽  
Vol 42 (12) ◽  
pp. 1954-1956 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken

Female American lobsters, Homarus americanus, seldom are receptive to mating more than 24 h after they molt, a fact that complicates breeding programs in large facilities where animals are held individually. Artificial insemination can eliminate this problem, but preliminary studies have indicated poor fertilization success from intermolt inseminations. In the present study, 86 female American lobsters of wild and cultured stock were artificially inseminated in all postmolt and intermolt stages, 64 subsequently spawned, and 98% successfully fertilized their eggs, indicating no constraint of molt stage on success of insemination. Of artificially inseminated females, 50% of wild stock and 7% of cultured stock carried their eggs to hatch.


Aquaculture ◽  
2008 ◽  
Vol 281 (1-4) ◽  
pp. 43-48 ◽  
Author(s):  
Sandra Joaquim ◽  
Domitília Matias ◽  
Belisandra Lopes ◽  
William S. Arnold ◽  
Miguel B. Gaspar

1999 ◽  
Vol 77 (10) ◽  
pp. 1573-1578 ◽  
Author(s):  
Dave Shutler ◽  
C Davison Ankney ◽  
Adele Mullie

The blood parasite Leucocytozoon simondi is often associated with heavy mortality of ducks and geese, especially domestic ones, in North America. In contrast, in a previous study we found no mortality from L. simondi in our wild stock of mallard (Anas platyrhynchos) and American black duck (Anas rubripes) ducklings. However, because parasites can slow growth, which could extend the interval during which ducklings are susceptible to predators, we tested for parasite effects on growth rates. We analysed growth rates over the first 20 days of life, based on tarsus length, culmen, bill width, body mass, and a principal component of structural size. Growth rates of infected ducklings were not lower than those of uninfected ducklings. Similarly, more intense infections did not have a greater effect on growth rates. Hence, growth rates were not negatively affected by L. simondi, which suggests that effects of this parasite on wild duck populations have been overestimated.


1960 ◽  
Vol 1 (1) ◽  
pp. 151-172 ◽  
Author(s):  
E. C. R. Reeve

1. Published data suggest that mean left-right asymmetry in number of sternopleural bristles of D. melanogaster declines when inbred lines are crossed, while the corresponding variance for sternite bristles remains unchanged. Some genetic tests were undertaken to analyse this difference in behaviour of the two characters.2. A progeny test on a wild stock showed that a small amount of genetic variance in sternopleural asymmetry was present, equivalent to about 2% of the total phenotypic variance.3. It was possible to increase and decrease the level of sternopleural asymmetry in two wild stocks by selection. These experiments gave an estimated heritability of some 2–3%, in close agreement with the progeny test. Change in asymmetry did not necessarily lead to a change in mean count.4. Homozygous lines, consisting of individual third chromosomes from the Renfrew wild stock made homozygous in an inbred line genetic background, were intercrossed, and the average indices for a number of characters of eight inter crosses involving eight lines were compared with their mid-parent averages. Thorax length was 2% greater and its variance 32% less in the crosses; total sternopleural count and its variance did not change significantly, but the asymmetry variance declined by 18%. In contrast, the corresponding asymmetry or independent variance for numbers of sternite bristles was 6% higher in the crosses, although the total sternite count and its variance did not change. These results fit in with previous work.5. Tests on a similar set of homozygous lines in which the third chromosomes came from the SP wild stock, and on some long inbred lines from the Pacific wild stock, gave discordant results. Of eight SP lines examined, four were homozygous for a gene polychaetoid, and four were homozygous for a genetic effect causing sockets without bristles to occur among the sternopleurals. Both types had much greater sternopleural variance and asymmetry than the Renfrew lines, and both indices declined sharply in intercrosses leaving these genetic effects heterozygous, but neither declined if they were left homozygous in the crosses. Similarly high sternopleural variances were found in the Pacific lines, but only the total variance declined in males and only the asymmetry variance declined in the females, when they were intercrossed. All the four Pacific lines tested appeared to be homozygous for a genetic effect which caused a variable number of dorso-central and scutellar bristles to be replaced by sockets without bristles, and an occasional extra scutellar bristle to appear. This effect was also probably responsible for the high sternopleural variances.6. Males of the Pacific inbred lines and intercrosses were compared when reared on the normal live medium and on a synthetic diet in reduced concentration, which reduced body-size by 23% (thorax area). The inbred lines were reduced more than the F1's in total sternopleural count and its variance, but the F1's were reduced more in sternopleural asymmetry, by the restricted diet.7. The problems of interpreting these experiments, in view of our ignorance of the biological functions and attributes of the sternopleural and sternite bristles, are discussed. It is concluded that we have no basis yet for deciding whether sternopleural bristle number is of adaptive significance, but this is considered improbable.8. The experimental evidence suggests that sternopleural asymmetry cannot be considered a measure of general developmental stability, particularly as the level of asymmetry can be reduced by selection well below that of typical wild stocks.9. The scaling problems arising when the mean asymmetry of lines with different mean counts are to be compared, are examined, and it is suggested that the ratio of asymmetry to total count does not eliminate scale effects.10. Developmental and anatomical differences between the sternopleural and sternite bristles suggest a possible reason why they behave differently when inbred lines are intercrossed.


2018 ◽  
Vol 19 (1) ◽  
pp. 337-342
Author(s):  
RAKHMA FITRIA LARASATI ◽  
SUADI SUADI ◽  
EKO SETYOBUDI

Larasati RF, Suadi, Setyobudi E. 2018. Short Communication: Population dynamics of double-spined rock lobster (Panulirus penicillatus Olivier, 1791) in Southern Coast of Yogyakarta. Biodiversitas 19: 337-342. The southern coast of Yogyakarta, Indonesia, near to the Indian Ocean borders is a preferable habitat for lobster. Double-spined rock lobster (Panulirus penicillatus) is one of the prevalent species caught by fishermen. However the increased number of capture activities had an effect on the sustainability of global lobster fisheries. In order to sustain these fisheries resource, the preservation management of lobster should include wild stock assessments. Currently, the effect of fishing pressures on populations of P. penicillatus is limited. The objective of this research was to identify several factors affecting lobster population in terms of growth (carapace length (CL) and mass), recruitment, mortality rates, and exploitation rates in this species. Results showed that double-spined rock lobster had a longer size (CL) (45.2-55.1 mm) than that of females (55.2 mm-65.1 mm). While the growth rate (K) of males lobster is 0.85 year-¹ and its CL reached an asymptotic point at 125 mm (12 years old). Growth rate of females double-spined rock lobster was 0.55 year-¹ and its CL reached an asymptotic point at 125.5 mm (15 years old). The total estimation of mortality rates of double-spined rock lobster was 2.46, wherein 2.56 year-¹ for males and females, respectively. The estimated values of M were 1.08, 0.81 year-¹ for males and females, respectively while the respective values of F were 1.38 year-¹ and 1.75 year-¹ for males and females. The exploitation rate of males was 0.56 and females was 0.68. It has exceeded the optimal level (0.5) and reached overfishing value. Based on these results, it suggest that the time management of fishing activities such as by several approaches including the restricted time of fishing activity in spawning and recruitment season, the management of catching effort by the development of environment-friendly fishing gear, and the development of the lobster hatchery to reproduce and maintain their population naturally.


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