Crustacean genetics and breeding: An overview

Aquaculture, 33 (1983) 395-413 Elsevier Science Publishers B.V., Amsterdam -Printed

CRUSTACEAN

GENETICS

AND BREEDING:

in The Netherlands

395

AN OVERVIEW

SPENCER R. MALECHA Prawn Aquaculture Research Program, Department Hawaii, Honolulu, HI 96822 (U.S.A.) (Accepted

of Animal Science,

University of

19 January 1983)

INTRODUCTION

The purpose of this review is to give a general overview of crustacean aquabreeding and to serve as a quick entry to the literature. Non economically important groups (“animal models”) are mentioned for their heuristic value and our published work and unpublished experience with the freshwater prawn Macrobruchium rosenbergii is used to illustrate specific points. Of all the aquaculturally important groups crustaceans have the least amount of genetic research applied to them. However, in the last 20 years there has been enough research to mandate the review by Hedgecock et al. (1982) in the update of the well-known work by Waterman (1960) which did not have a chapter on genetics; cytogenetics vis a vis sex determination has been reviewed by Ginsburger-Vogel and Charniaux-Cotton (1982). Table I, derived from the papers cited by Hedgecock et al. (1982), shows that crustacean genetics is dominated by Artemia biochemical genetics, color polymorphism and electrophoresis. Less than 1% of the genetic work done on crustaceans has been of an applied nature but has involved all the major economically important taxa except crayfish. The aquacultural crustaceans, like some fishes and molluscs, are undomesticated and applied crustacean genetics is still largely restricted to assessing genetic variation. Although some effort is being made to develop this varia tion, there has been no selection done on the crustaceans, and no genetic groups developed by direct human intervention are available. ASSESSMENT OF VARIATION

Species selection Nelson (1977) discusses the kinds of genetic assessment needed to determine a species potential for domestication. Several studies have been aimed at interspecific (“side-by-side”) comparisons of species performances. Noteworthy for lobsters is the comparison by Gruffydd et al. (1975) of larval growth and temperature tolerances in the European and American lobsters.

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0 1983 Elsevier Science Publishers B.V.

396

TABLE I Categories and approximate al. (1982)

number of crustacean genetics papers cited in Hedgecock et

Category

No.

Artemia:

45 8 75 30 31 28 5 6 8 3 5 5 7 7 5 12 14

Biochemical genetics Other Color polymorphism DNA enumeration Electrophoresis: Micro crustacean Macro crustacean Broodstock* General Hybridization* Heterosis Heritability* Morphological Physiological genetics Parthenogenesis Reproductive biology Population biology Other *Denotes applied aquaculture application.

The CNEXO Aquacop group in Tahiti has evaluated reproductive performances of several penaeid species (Aquacop, 1977, 1979). Comparisons in productive capabilities of both penaeids and prawns have been carried out by the group in Conway, England (Forster and Beard, 1974). The St. Petersburg (Florida) group has done comparisons of Mucrobrachium larval biology and husbandry (Dugan et al., 1975; Hagood and Willis, 1976). Miyajima (1977) compared both larval and adult growth in several Macrobruchium species. Population electrophoresis (allozymic variation) Nelson and Hedgecock (1980) in an exhaustive review surveyed 44 species of decapod crustacea and correlated electrophoretic variability levels with habitat and niche descriptors and found that in crustaceans electrophoretic genetic variability is low both in terms of the degree of polymorphism and average heterozygosity among loci. Tracey et al. (1975) have surveyed electrophoretic variation in American lobster (H. americanus) populations and Hedgecock et al. (1977) have compared the electrophoretic variation in the American and European (H. gummarus) lobsters. Inter-population differences in H. americanus are smd but the species can be separated into inshore and offshore groups. H. americanus is electrophoretically similar to H. gammarus. Predictably, electrophoretic variation in lobsters is controlled by autosomal co-dominant alleles (Hedgecock et al., 1975).

Lester (1979) electrophoretically surveyed the economically important Gulf of Mexico penaeid shrimp, Penaeus aztecus, P. seriferus and P. duorurum and found little subpopulation differentiation within each species. Mulley and Latter (1980) electrophoretically analyzed six Metapenaeus species and seven Penaeus species of fishery and/or aquaculture importance in Australia, including P. monodon, P. merguiensis and P. semisulca tus. There were marked low levels of genetic variability measured both in terms of average hetero zygosity and percentage of polymorphic loci. Genetic identity (Nei: 1972) among the Metapenaeus and Penaeus species ranged from 0.59 to 0.82 for the former and between 0.52 to 0.84 for the latter. Identities between the two genera ranged from 0.32 to 0.49. Fuller and Lester (1980) showed that genetic variability in Palaemonetes pugio is less in land locked ponds than in lagoons and bays. Hedgecock et al. (1979), Stelmach (1980) and Malecha et al. (in prep.) have electrophoretically surveyed Mucrobruchium rosenbergii and have demonstrated a major intraspecific dichotomy into a Western and Eastern group. The latter can be further differentiated into an Australian and North Eastern group. The identity measure within and between the Eastern and Western groups are similar to what Lester (1979) found within the penaeid species. The between group identities are similar to values usually encountered between species (Avise, 1978). However, the intraspecific groups will freely hybridize (Malecha, 1981) lending little credence to the use of electrophoresis to predict hybridization capabilities. Trudeau (1978) surveyed M. ohione and showed that there is little allozymic differentiation between populations. Intraspecific variation Physiological and morphometric variation The intraspecific physiological variation in crustacean species that has been documented (Tashian, 1966; Vernberg, 1962; Battaglia and Bryan, 1964) correlates with latitude (Vernberg, 1962). Strong (1972,1973) found intraspecific variation in life history parameters among amphipod populations. Ogasawara et al. (1979) demonstrated an interesting variation in salinity tolerance among lake and river populations of the native Japanese Macrobruchium nipponense. Choudhury (1971b) gave evidence of a possible difference in salinity tolerance between M. carcinus from Barbados and Jamaica. Williamson (1972) refers to subspecific morphometric variation between M. niloticum found in Lake Chad and Lake Rudolf. Crustacean carcasses include a significant portion of unedible parts which can be minimized as a general consequence of domestication itself (Fabian, 1969) or as a response to genetic selection (Robertson, 1962). However, existing intraspecific variation should be assessed since intraspecific geographic populations of lobsters (Templeton, 1935; Tessier, 1936), crabs (Williams and Needham, 1941), amphipods (Chevias, 1937), isopods (Bocquet, 1953) have all been shown to vary in the relative dimensions of body parts.

398

Intraspecific morphometric and allometric variations have been extensive!y surveyed by our group (Hedgecock et al., 1979; Lindenfelser, 1980; Stelmath, 1980; Malecha et al., in prep.). Preliminary reports have appeared in Malecha et al. (1980) and in Sandifer (1981). All in all, M. rosenbergii is uniform in economically important carcass characteristics like head to tail and claw to body ratios. However, multi-variant and discriminate function analysis among geographic groups readily discerns individual populations and clearly dichotomizes the species into Eastern and Western groups (Lindenfelser, 1980). There has not been very much published information on intraspecific variation within lobster or penaeid species. Brown et al. (1980) found maturation and spawning performance differences between Costa Rican and Mexican P. stylirostris. Templeton (1935) showed a difference between lobster populations in chelar development. This was correlated with differences in the onset of sexual maturity between the two populations studied. Our work with M. rosenbergii has uncovered considerable electrophoretic and color polymorphism but relatively little physiological variation (Malecha, 1981) although variation in larval development growth pattern and juvenile temperature and salinity tolerances have been found (Sarver et al., 1979). The Australian group showed significantly abbreviated larval developa trait of potential importance in future genetic improvement. ment time Dobkin et al. (1974) could not find any differences in pond performance between Thailand and Anuenue stocks of M. rosenbergii. Malecha et al. (1980) likewise found no differences in various growth parameters between Anuenue and an ancestral Malaysian stock. Although we found that M. rosenbergii is well adapted to hypoxia, surprisingly there were no differences among the Western, Australian, and North Eastern geographic groups (Mauro and Malecha, in prep.). We concluded that prawn domestication could not utilize geographic group differences and that it would be best to alter the culture environment rather than the. prawn genotype. In the long term, group differences between families and individual differences could be the subject of direct or domestication selection (Doyle, 1983, this volume). In crustaceans most economically useful intraspecific variation seems to be in latitudinal not longitudinally distributed species. A priori, crustacean species that have north/south distributions, especially those that encompass both temperate and tropical or semi-tropical areas, can be expected to have readily discernable physiological variation among geographic groups. Phenotypic and genotypic variance Since growth over a time interval is allometric, i.e. it is a power function of the weight at the beginning of the interval, all populations with non-zero size frequency distribution variances will depensate (Ricker, 1975) -- increase their variance over time. However, coefficients of variation (standard

399

deviation/mean) and third moment functions increase only slightly. The growth pattern of M. rosenbergii, especially males, appears to be the result of factors other than normal allometric growth such that the coefficient of variation increases considerably along with the third moments of the size frequency distribution resulting in highly skewed, nearly bimodal distributions. This seriously affects prawn product value since prices paid for them are dependent on individual size (Smith et al., 1980). This effect is not as pronounced in penaeids and lobsters who have normal allometric depensation. The large prawn male modal group has been named “bulls” (Fujimura and Okamoto, 1972) and seems equivalent to “shoot” carp, or Tobi koi (Nakamura and Kasahara, 1965) and “jumpers” (Moav and Wohlfarth, 1973). Our work (Malecha et al., 1981) has shown that a prawn’s size and age seem to have little correlation with its growth capacity: heterogeneous individual growth (HIG) seems to require induction in free living aggregate populations of either sex; small size is fully reversible, individual rearing ameliorates HIG but not normal allometric depensation, and finally monosex rearing affects neither. HIG is a non-genetic phenomenon in carp (Moav and Wohlfarth, 1973). We have shown (Malecha et al., in review) that the genetic variance of juvenile M. rosenbergii male growth is negligible but that female growth is significantly heritable. The first estimation of genetic variance in economically important crustaceans was done in the lobster, H. americanus, by Hedgecock et al., (1976a) and Hedgecock and Nelson (1978) who found that growth in laboratory reared juveniles is about 30% heritable. However, the culture system itself (Hand et al., 1977), family by system interaction and density differences within and between systems contributed substantially to the total variance. Later Nelson et al. (1980) showed that a short lived water borne factor produced by larger juveniles inhibits the growth of smaller ones in “downstream” compartments. Fairfull and Haley (1981) in Nova Scotia estimated genotypic and phenotypic growth rate parameters and conditions. Genetic variation was found under all test conditions and was large enough to be able to produce a re sponse in growth traits to artificial selection. Finley and Haley (1983) estimated the heritability of certain aggressive behaviors in H. americanus. TO date there have been no estimates of genetic variance in penaeid shrimp. McLaren (1976) and McLaren and Crockett (1978) have estimated genetic variance using nested designs in marine copepods. Karyology Niiyama (1959, 1962, 1966) is probably the best starting point for decapod karyology. However, the recent review by Ginsburger-Vogel and Charniaux-Cotton (1982) shows what we know of the karyology of crustacean vis a vis sex chromosomes and sex determination. As expected there is considerable work on Artemia and micro crustaceans and relatively little on economically important decapods.

400

Lobsters, penaeids and prawns appear to be diploid with no evidence of sex chromosomes morphologically distinct from the autosomes. However, sex-determination can be expected to be homo-heterogametic and either genie or chromosomal (Ginsburger-Vogel and Charniaux-Cotton, 1982). Roberts (1969) suggested the presence of supernumerary chromosomes in lobsters. This was confirmed by Hughes (1982) who also showed that there is little difference in meiosis between H. gummarus and H. americanus. Milligan (1976) karyotyped three penaeid species: P. aztecus, P. setiferus, and P. duorarum. Mittal and DhaIl(l971) showed that 2n = 100 inMacrobruchium siwalikensis. Hasegawa (1981) recently described a rapid technique for crustacean chromosome analysis. Domestication effects Because the wild relatives of all aquacultured species are extant there is a unique opportunity in aquaculture to assess both the effect and process of domestication. This area is most well developed in crustaceans thanks to Doyle and his co-workers who outlined theoretical aspects of the genetic changes which occur during domestication (Doyle, 1979,1980, 1983; Doyle and Hunte, 1980,1981a, 1981b; Doyle and Meyers, 1981;Doyle et al., 1983). For example, Doyle and Hunte (1981a) showed that heritable changes in Gammarus Zawrenciunus life history parameters of survivorship and fertility occur as the result of natural selection within the culture environment (“domestication selection”), i.e. species can evolve under culture and could acquire adaptations which are uneconomical. Doyle and Hunte (1980) argue that it may be advantageous to first let this “domestication selection” run its course in order to increase population fitness before conventional selection for production traits is done. Recently Doyle et al. (1983) argue that small changes in management practices in artisanal M. rosenbergii farming could exert strong indirect selection on growth rate. Indeed we have shown that a M. rosenbergii stock under cultivation differed little from its ancestral stock and that current management practices of broodstock selection are counter productive to progressive prawn domestication since the pedigree and age structures are not controlled (Malecha et al., 1980). We argued that high larval survival under culture, compared to that in the wild, has served to “flush” the cultured M. rosenbergii gene pool in a manner similar to that described by Carson (1968, 1975) for the genetic events occurring during rapid speciation following colonization. “Flushes” are the increases in population numbers by survival and they “open up” the species genotype by fostering new genetic combinations, e.g. when a species is removed from one niche (i.e. the wild) and placed in a new one (i.e. under culture). It seems that the M. rosenbergii gene pool has been “flushed” but not “winnowed” (after Spurway, 1955) such that there are no difference between the cultured and wild states as yet.

401 DEVELOPMENT

OF GENETIC VARIATION

Broodstock development Although the life cycle of lobsters has been controlled for a number of years (Hughes and Matthiessen, 1962; Aiken and Waddy, 1976) it was not until recently that proper photoperiod control of the female egg extrusion was worked out by the University of California Bodega Bay Marine Lab group (Hedgecock, 1983; Nelson et al., 1983); it is now possible to rely on laboratory broodstock for commercial lobster culture. Hedgecock et al. (1976b) and Hedgecock (1977) emphasized the use of electrophoretic markers in lobster broodstock development and Nelson and Hedgecock (1976) demonstrated their use in determining multiple paternity. Broodstock management for genetic improvement is least developed among the penaeids despite the fact that the life cycle is controlled to some degree among most of the economically important penaeid species(Aquacop, 1977, 1979; Laubier-Bonichon, 1978; Beard and Wickens, 1980; Brown et al., 1980; Lawrence et al., 1980). Single pair (“one on one”) matings have not been accomplished. For P. stylirostris Brown et al. (1980) utilized between one and two dozen animals of each sex in a 1 : 1 sex ratio in a spawning tank. Repeat spawnings were common: 35 females gave 247 spawnings. In situations like these, which appear typical for penaeids, paternity is difficult to trace. Indeed, Lester (1983, this volume) is developing paternity tracking electrophoretic methods for penaeid broodstocks. Lack of single pair mating capability prevents extensive genetic variance estimation since sire effects cannot be assessed and nested designs are impossible. However, mass spawning should not prevent artificial (mass) selection programs. Conte et al. (1977) showed that between 15- 50% of female and nearly 100% of male P. stylirostris matured in culture ponds, enough for suitable selection differentials. Of the three economically important crustacean taxa, prawns (M. rosen bergii) require the least amount of environmental manipulation to spawn in captivity (Malecha, 1983). We were able to achieve nested designs for genetic variance estimation of as much as four dams per sire (Malecha et al., 1983). Males can mate several times per day and female pre-nuptial molts occur throughout the year (Rao, 1965; Chow et al., 1982). In our broodstock program in Hawaii (Malecha, 1981), since October 1977 we made over 1000 single pair matings representing 19 geographic parental and hybrid groups and four generations. Hybridization by natural service American and European lobsters are inter-fertile and hybrids between them have potential in genetic improvement programs. Carlberg et al. (1978) successfully hybridized the European (H. gammarus) and American (H.

umericanus) lobsters and found that hybrid development rates, growth, and various morphometric variables were intermediate between parental values. Egg extrusion and hatchery ability were higher in the hybrid. In contrast, T. Kittaka, N. Chida and T.P. Mercer (personal communication, 1982), hybridized H. gammarus and H. americanus and observed evidence of hybrid vigor in larval growth - but on the basis of only one family. Sankolli et al. (1982) report a successful natural service mating between M. rosenbergii and M. malcomsonii. Shokita (1978) obtained hybrids between M. asperulum and M. shokitai. Intraspecific hybridizations of M. rosenbergii geographic groups have been extensively carried out in Hawaii by us (Malecha, 1981) and demonstrate inter-fertility among all groups including the highly electrophoretically differentiated Eastern, Western, and Australian groups (Hedgecock et al., 1979). This indicates that genetic distances usually indicative of species differences are not ipso facto predicators of hybridization success. Hybridization by artificial insemination (Al) Sandifer and Smith (1979) developed methods for artifical insemination in Mucrobrachium sp. based on sacrifice of the male and manual extrusion of the spermatophore. Sandifer and Lynn (1980) extended this work by describing a male sparing, electro-ejaculation method. These authors report successful hybridization between two closely related Pulaemonetes species. Hybridizations among M. acanthurus, M. rosenbergii, M. ohione, and M. olfersi, using A.I. techniques were unsuccessful. Tave and Brown (1981) describe a method to aid in penaeid shrimp spermataphore transfer. Sex control

Because of the dramatic sexual dimorphic growth in M. rosenbergii and in at least one commercially important penaeid, P. monodon (Liao, 1977), males and females should be managed differently. This could be done by culturing the sexes separately, as done in fishes, or in various sex ratios. However, unlike the case in fishes, the gametogenic and sexual differentiation functions in crustaceans are localized in anatomically distinct glands, the testes and androgenic gland, located near the terminus of the vas deferens (Chsrniaux-Cotton et al., 1966; Thampy and John, 1970, 1973). The gland is peculiar to Malacostracan crustaceans and was originally discovered by CharniauxCotton (1954) and shown by her (1959) and others (Katakura, 1959, 1960, 1961) to be capable of masculinizing a female when transplanted into the latter. Katakura (1961) produced viable (allfemale) progeny from the mating of a masculinized and normal female in an isopod. Recently Nagamine et al. (1980b) showed that M. rosenbergii females can be masculinized by implantation of androgenic gland tissue dissected from males, and Nagamine et al. (1980a) also showed that andrectomized male M. rosenbergii develop female gonopores externally

403

and oviducts and oogenesis internally in an ovotestis. In view of these results and those of Katakura (1961) it may be possible to cross a sex-reversed M. rosenbergii “neo-male” (genetic female) with a normal female or an andrectomized male with normal male to produce monosex progeny. Sexual steroids, although present in crustaceans (Sandor, 1980), have not been shown to have the same effect on sexual differentiation as in vertebrates (Nagabhushanam and Kulkarni, 1981). CONCLUSION

Crustaceans are relatively genetically unexplored and there are a number of major constraints to overcome this (Table II). Notably, the lack of suitable individual tags due to ecdysis constrains genetic evaluation and selection designs although we have made some progress in this area (Malecha and Prentice, in prep.) following the methods described by Prentice and Rensel (1977). In some cases there may be a lack of a bone fide need because consistent culture systems have not been established due to the age of the industry. In my opinion, one cannot develop an industry through genetic selection; one can only optimize it once an industry, albeit a fledging one, is developed. TABLE II Some major constrains in crustacean aqua-breeding Category

Example

Age of aquaculture: no domesticates Open life cycle Closed but cumbersome life cycle: no massive single-pair mating Lack of an individual tag Lack of bona fide need because of limited industrial development Heterogeneous individual growth

all species crabs lobsters, penaeids all species lobsters, penaeids, crabs prawns

ACKNOWLEDGEMENTS

Thanks go to Amy Dicksion and Deb Ciampa for editorial and clerical assistance in preparing earlier drafts of this manuscript. Jean Murai, Kate Laws and Paula Borden provided similar assistance for the final drafts. The assistance of Gideon Hulata, who provided critical analysis and helpful suggestions, is gratefully acknowledged. The preparation of this report was supported by the State of Hawaii, Aquaculture Development Program and the University of Hawaii Sea Grant College Program (Project A/R-8) under Institutional Grant Nos. NA 79 AAD-00085 and NA 81 AA-D-00070 from NOAA, Office of Sea Grant Department of Commerce. This is Sea Grant Publication No. UNIHI - SEA GRANT JC-83-14.

404 REFERENCES Aiken, D.E. and Waddy, S.L., 1976. Controlling growth and reproduction in the American lobster. Proc. World Maricult. Sot., 7: 415-430. Aquacop, 1977. Observations on the maturation and reproduction of penaeid shrimp in captivity in a tropical medium. Aquaculture Workshop, ICES, May 10-13, Brest, pp. l-34. Aquacop, 1979. Penaeid reared broodstock: closing the life cycle of P. mondon, P. stylisterstris, P. vannamei. Proc. World Maricult. Sot., 10: 445-452. Atkinson, J.M., 1977. Larval development of a freshwater prawn, Macrobrachium Zar (Decapoda, Palaemonidae) reared in the laboratory. Crustaceana 33 (2): 119-132. Avise, J.C., 1978. Genetic differentiation during speciation. In: F.S. Ayala (Editor), Molecular Evolution. Sinauer Assoc. Inc., Sunderland, MA. Battaglia, B. and Bryan, G.W., 1964. Some aspects of ionic and osmotic regulation in !&be (copepoda, Harpacticoida) in relation to polymorphism and geographical distribution. J. Mar. Biol. Assoc. U.K., 44: 17-31. Beard, T.W. and Wickens, J.F., 1980. Breeding of Penaeus monodon Fabricus in laboratory recirculation systems. Aquaculture, 20: 79-80. Bocquet, C., 1953. Recherches sur le polymorphisme nature1 des Joera marina (Fabr) (Isopoda Asellotes). Essai de systematique evolutive. Arch. Zool. Exp. G&r., 90: 187450. Brown, A., McVey, J.P., Scott, B.M., Williams, T.D. Middleditch, B.S. and Lawrence, A.L., 1980. The maturation and spawning of Penaeus stylirostris under laboratory conditions. Proc. World Maricult. Sot., 11: 488-499. Carlberg, J.M., Van Olst, J.C. and Ford, R.F., 1978. A comparison of larval and juvenile stages of the lobsters Homarus americanus, Homarus gammarus, and their hybrids. Proc. World Maricult. Sot., 11: 488-499. Carson, H.L., 1968. The population flush and its genetic consequences. In: Population Biology and Evolution. Syracuse University Press, Syracuse, NY. Carson, H.L., 1975. The genetic consequences of speciation at the diploid level. Am. Nat., 109 (965): 83-92. CharniauxCotton, H., 1954. Decouverte chez un Crustace Amphipode Orchestia gamarella d’une glande endocrine responsable de la differentiation des caracteres sexuels premieres et secondaires males. CR. Acad. Sci. Ser. D., 239: 780--782. Charniaux-Cotton, H., 1959. Masculinization des femelles de la Crevette 1 hermaphrodisme proterandrique Lysmata seticaudata, par greffe de glandes androgenes. Interpretation de I’hermaphrodisme chez les Decapodes. Note preliminaire. C.R. Acad. Sci. Ser. D, 249: 1580-1582. CharniauxCotton, H., Zerbib, C. and Meusy, J.J., 1966. Monographie de la glande androgene des Crustaces superieurs. Crustaceana, 10: 113-136. Chevias, S., 1937. Croissance et races locales de Corophium volutator. Trav. Sta. Biol. Roscoff, 16: 103-131. Choudhury, P.C., 1970. Complete larval development of the Palaemonid shrimp, Macrobrachium acanthurus (Wiegmann) reared in the laboratory. Crustaceana, 18 (2): 113132. Choudhury, P.C., 1971a. Complete larval development of the Palaemonid shrimp, Macrobrachium carcinus (L), reared in the laboratory. Crustaceana, 20 (1): 51-69. Choudhury, P.C., 1971b. Responses of larval Macrobrachium carcinus to variations in salinity and diet. Crustaceana, 20 (2): 113-120. Choudhury, P.C., 1971c. Laboratory rearing of the Palaemonid shrimp, Macrobrachium acanthurus. Crustaceana, 21 (2): 113-126. Chow, S., Ogasawara, Y. and Taki, Y., 1982. Male reproductive system and fertilization of the Palaemonid shrimp, Macrobrachium rosenbergii. Bull. Jpn. Sot. Sci. Fish., 48 (2): 177-183.

405 Conte, F.S., Duronslet, J.J., Clark, W.H. and Parker, J.C., 1977. Maturation of Penaeus stylirostris (Stimpson) and P. setiferus (Linn.) in hypersaline water near CorpusChristi, Texas. Proc. World Maricult. Sot., 8: 327-334. Dobkin, S., 1969. Abbreviated larval development in caridean shrimps and its significance in the artificial culture of these animals. F.A.O. Fish. Rep., 57 (3): 935-946. Dobkin, S., 1971. A contribution to knowledge of the larval development of Macrobrachium acanthurus. Crustaceana, 21 (3): 294-297. Dobkin, S., Assinaro, W.P. and Van Montfrans, J., 1974. Culture of Macrobrachium acanthurus and M. carcinus with notes on the selective breeding and hybridization of these shrimps. Proc. World Maricult. Sot., 5: 51-62. Doyle, R.W., 1979. Rapid heritable changes in the biology of a malacostracan crustacean selected for improved yield in a model aquaculture program: genetic basis and economic implications. ICES Ref., CM 1979/F: 56. Doyle, R.W., 1980. Selection and inbreeding of cultivated Macrobrachium rosenbergii in Thailand. FAO/UNDP/THA/008/75. Doyle, R.W., 1983. An approach to the quantitative analysis of domestication selection in aquaculture. Aquaculture, 33: 167-185. Doyle, R.W. and Hunte, W., 1980. The importance of selecting for survivorship in genetic yield improvement programs in crustacean aquaculture. Proc. World Maricult. Sot., 11: 500-551. Doyle, R.W. and Hunte, W., 1981a. Genetic changes in “fitness” and yield of a crustacean population in a controlled environment. J. Exp. Mar. Biol. Ecol., 52: 147-156. Doyle, R.W. and Hunte, W., 1981b. Demography of an estaurine amphipod (Gammarus Zawrencianus) experimentally selected for high “r”: a model of the genetic effects of environmental change. Can. J. Fish. Aquat. Sci., 38 (9): 1120-1127. Doyle, R.W. and Myers, R.A., 1981. The measurement of the direct and indirect intensities of natural selection. In: H. Dingle and J. Hegmann (Editors), Variation in Life Histories: Genetic and Evolutionary Processes. Springer-Verlag, New York. Doyle, R.W., Singholka, S. and New, M.B., 1983. “Indirect selection” for genetic change: a quantitative analysis illustrated with Macrobrachium rosenbergii. Aquaculture, 30: 237-247. Dugan, C.C., Hagood, R.W. and Frakes, T.A., 1975. Development of spawning and mass larval rearing techniques of brackish-freshwater shrimps of the genus Macrobrachium (Decapoda, Palemonidae). Fla. Mar. Res. Publ. No. 12, 28 pp. Fabian, G.Y., 1969. Phaenoanalysis and Quantitative Inheritance. Akademiae Kiado, Budapest. Fairfull, R.W. and Haley, L.E., 1981. The early growth of artificially reared American lobsters. Theor. Appl. Genet., 60: 269-273. Fielder, D.R., 1970. The larval development of Macrobrachium au&dense Holthuis, reared in the laboratory. Crustaceana, 18 (1): 60-74. Finley, L.M. and Haley, L.E., 1983. The genetics of aggression in the juvenile American lobster, Homarus americanus. Aquaculture, 33: 135-139. Forster, J.R.M. and Beard, T.W., 1974. Experiments to assess the suitability of nine species of prawns for intensive cultivation. Aquaculture, 3: 355-368. Fujimura, T. and Okamoto, O.H., 1972. Notes on progress made in developing a mass culturing technique for Macrobrachium rosenbergii in Hawaii. In: T.V.R. Pillay (Editor), Coastal Aquaculture in the Indo-Pacific Region. Fishing News Books, Ltd., London, pp. 313-327. Fuller, B. and Lester, L.J., 1980. Correlations of allozymic variation with habitat parameters using the grass shrimp, Palaemonetespugio. Evolution, 34 (6): 1099-1104. Ginsburger-Vogel, T. and Charniaux-Cotton, H., 1982. Sex determination. In: D.E. Bliss (Editor), The Biology of Crustacea, Vol. 2: Embryology, Morphology and Genetics. Academic Press, New York, pp. 257-281. Gruffydd, L.D., Riser, R.A. and Machin, D., 1975. A comparison of growth and temperature tolerance in the larvae of lobsters Homarus gammarus and Homarus americanus H. Milne Edwards (Decapoda, Nephorpidae). Crustaceana, 28 (1): 23-32.

406 Hagood, R.W. and Willis, S.A., 1976. Cost comparisons of rearing larval of freshwater shrimp, Macrobrachium acanfhurus and M. rosenbergii, to juvenile. Aquaculture, 7: 59-74. Hand, C., Albany, T., Botsford, L., Conklin, D., Daggett, R., Fisher, B., Hartman, M., Hedgecock, D., Nelson, K. and Nilson, E., 1977. Development of aquaculture systems. University of California Sea Grant College Program, IMR Ref. 77-105, Sea Grant Publ. 58, Inst. Marine Resources, 97 pp. Hasegawa, M., 1981. Simple and rapid technique for a chromosome study of crustacea. Researches on Crustacea No. 11, Carcinology Sot. Japan, Odawara Carcinological Museum, Azabu-Tuban 3-11 Minatoku, Japan (in Japanese, with English abstract). Hedgecock, D., 1977. Biochemical genetic markers for broodstock identification in aquaculture. Proc. World Maricult. Sot., 8: 523-531. Hedgecock, D., 1983. Section II. Maturation and spawning lobster. In: J.P. McVey (Editor), CRC Handbook of Marine Science, Vol. I. Aquaculture of Crustaceans. CRC Press, Inc., Boca Raton, FL, in press. Hedgecock, D. and Nelson, K., 1978. Components of growth rate variation among laboratory cultured lobsters (Homarus). Proc. World. Maricult. Sot., 9: 125-137. Hedgecock, D., Nelson, K., Shleser, R.A. and Tracey, M.L., 1975. Biochemical genetics of lobsters (Homarus). II. Inheritance of allozymes in H. americanus. J. Hered., 66: 114118. Hedgecock, D., Nelson, K. and Shleser, R.A., 1976a. Growth differences among families of the lobster, Homarus americonus. Proc. World Maricult. Sot., 7: 347-361. Hedgecock, D., Nelson, K. and Shleser, R.A., 1976b. Applications of biochemical genetics to aquaculture. J. Fish. Res. Board Can., 33: 1108-1119. Hedgecock, D., Nelson, K., Simons, J. and Shleser, R.A., 1977. Genie similarity of American and European species of the lobster Homarus. Biol. Bull., 152: 41-50. Hedgecock, D., Stelmach, D.J., Nelson, K., Lindenfelser, N.E. and Malecha, S.R., 1979. Genetic divergence and biogeography of natural populations of Mocrobmchium rosenbergii. Proc. World Maricult. Sot., 10: 873-879. Hedgecock, D., Tracey, M.L. and Nelson, K., 1982. Genetics. In: D.E. Bliss (Editor), The Biology of Crustacea, Vol. 2 Embrology, Morphology and Genetics. Academic Press, New York. Holthius, L.B., 1950. The palaemonidae collected by the Shiboga and Snellius Expeditions with remarks on other species. I. Subfamily Palaemonidae, the Decapoda of the Shiboga Expedition Part X. Shiboga Expedition Monograph, 39a(9): l-268. Holthius, L.B., 1951. The caridean Crustacea of tropical West Africa. Atl. Rep., 2: 7-187. Holthius, L.B., 1952. A general revision of the Palaemonidae of the Americas. 2. Subfamily Palaemonidae. Occas. Publ. Allan Hancock Found., 12: l-396. Holthius, L.B., 1980. Shrimps and Prawns of the World. An Annotated Catalogue of Species of Interest to Fisheries. F.A.O. Species Catalogue. Vol. 1. Fisheries Synopses No. 125, Vol. 1. F.A.O., Rome. Holthius, L.B. and Rosa, Jr., H., 1965. List of species of shrimps and prawns of economic value. FAO Fish. Tech. Pap. 52, 21 pp. Hughes, J.B., 1982. Variability of chromosome number in the Lobsters, Homarus omericanus and Homarus gammarus. Unpubl. MS. National Marine Fisheries Service, Northeast Fisheries Center, Milford Laboratory, Milford, CT. Hughes, J.T. and Matthiessen, G.C., 1962. Observations on the biology of the American lobster, Homarus americanus. Limnol. Oceanogr., 7 (3): 414-421. Ibrahim, K.H., 1962. Observations on the fishery and biology of the freshwater prawn Macrobrachium molcolmsoni M. Ed. of River Godavari. Indian J. Fish., 9A (2): 433467. Jalihal, D.R. and Sankolli, K.N., 1975a. On the abbreviated metamorphosis of the freshwater prawn Macrobrachium hendersodayanum (Tiwari) in the laboratory. Karnatak Univ. J. Sci., 20: 283-291.

407 Jalihal, D.R. and Sankolli, K.N., 1975b. On the palaemonid prawn Macrobrachium hendersodayanum (Tiwari) from the Malaprabha River. Karnatak Univ. J. Sci., 20: 297304. Katakura, Y., 1959. Masculinization through implanting testes into the female Armadillidum vu&are, an isopod crustacean. Proc. Jpn. Acad., 35: 95-98. Katakura, Y., 1960. Transformation of ovary into testes following implantation of androgenous glands in Armadillidium vulgare, an isopod crustacean. Annot. Zool. Jpn., 33(4): 241-244. Katakura, Y., 1961. Progeny from the mating of the normal female and the masculinized female of Armadiilidium vulgare, an isopod crustacean. Annot. Zool. Jpn., 34 (4): 197-199. Kemp, S., 1924. Crustacea Decapoda of the Siju Cave, Garo Hills. Assam. Rec. Dvd. Mus., 26: 41-48. Laubier-Bonichon, A., 1978. Ecophysiologie de la reproduction chez la crevette Penaeus japonicus: Trois annees d’experience en milieu controle. Oceanologica Acta, 1: 135150. Lawrence, A.L., Akamine, Y., Middleditch, B.S., Chamberlain, G. and Hutchens, D., 1980. Maturation and reproduction of Penaeus setiferus in captivity. Proc. World Maricult. sot., 11: 481-487. Lester, L.J., 1979. Population genetics of penaeid shrimp from the Gulf of Mexico. J. Hered., 70: 175-180. Lester, L.J., 1983. Developing a selective breeding program for penaeid shrimp mariculture. Aquaculture, 33: 41-50. Lewis, J.B., 1962. Preliminary experiments on the rearing of the freshwater shrimp, Macrobrachium carcinus (L). Proc. Gulf Carib. Fish. Inst., 14: 199-201. Lewis, J.B., 1965. Developmental stages of the palaemonid shrimp, Macrobrachium carcinus (Linn). Crustaceana, 9 (2): 137-148. Lewis, J.B., Ward, J. and McIver, A., 1966. The breeding cycle, growth, and food of the freshwater shrimp, Macrobrachium carcinus (L.). Crustaceana, 10 (1): 48-52. Liao, I-Chiu, 1977. A culture study on the grass prawn, Penaeus monodon, in Taiwan the patterns, the problems and the prospects. Contrib. B., No. 7 Collected Reprints Tungkang Marine Lab., Tungkang, Taiwan, Fish. Res. Inst., Vol. 3, 1974-1977. Lindenfelser, M.E., 1980. Subspecific variation and evolution in the freshwater prawn, Macrobrachium rosenbergii (de Man) (Decapoda: Palaemonidae) reflected in its morphometric and allozymic variation. PhD Dissertation, Dep. of Zool. Univ. of Hawaii, Honolulu, HI. Ling, S.W. and Costelleo, T.J., 1979. The culture of freshwater prawns: a review. In: T.V.R. Pillay and W.A. Dill (Editors), Advances in Aquaculture. Fishing News Books Ltd., Farnham, England, pp. 299-304. Malecha, S.R., 1981. Development and general characterization of genetic stocks of Macrobrachium rosenbergii and their hybrids for domestication. Univ. Hawaii Sea Grant Q. News, Vol. 2, No. 4,6 pp. Malecha, S.R., 1983. Commercial seed production of the freshwater prawn, Macrobrachium rosenbergii in Hawaii. In: J.P. McVey (Editor), CRC Handbook of Marine Science, vol. 1. Aquaculture of Crustaceans. CRC Press, Boca Raton, FL, in press. Malecha, S.R., Sarver, D. and Onizuka, D., 1980. Approaches to the study of domestication in the freshwater prawn, Macrobrachium rosenbergii, with special emphasis on the Anuenue and Malaysian stocks. Proc. World Maricult. Sot., 11: 500-528. Malecha, S.R., Bigger, D., Brand, T., Levitt, A., Masuno, S. and Weber, G., 1981. Genetic and environmental sources of growth pattern variation in the cultured freshwater prawn, Macrobrachium rosenbergii. Poster session, World Conference on Aquaculture, Venice, Italy, 21-25 September 1981. Malecha, S.R., Masuna, S. and Onizuka, D., 1983. Feasibility of measuring the heritability of growth pattern variation in juvenile freshwater prawn, Macrobrachium rosenbe&i (de Man). Aquaculture, in review.

408 McLaren, I.A., 1976. Inheritance of demographic and production parameters in the marine copepod Eurytemora herdmani. Biol. Bull., 151: 200-213. McLaren, I.A. and Crockett, C.J., 1978. Unusual genetic variation in body size development times, oil storage and survivorship in the marine copepod Pseudocalanus. Biol. Bull., 155: 347-359. Miller, G.C., 1971. Commercial fishery and biology of the freshwater prawn, Macrobrachium, in the Lower St. Paul River, Liberia. Spec. Sci. Rep. USFWS (Fish.), 626: l-3. Milligan, D.J., 1976. A method for obtaining metaphase chromosome spread from marine shrimp with notes on the karyotypes of Penaeus aztecus, Penaeus setiferus, and Penaeus duomrum. Proc. World Maricult. Sot., 7: 347-362. Mittal, O.P. and Dhall, V., 1971. Chromosome studies in three species of freshwater decapods (Crustacea). Cytologia, 36 (4): 633-638. Miyajima, L.S., 1977. About Macrobrachium species. In: J.A. Hanson and H.L. Goodwin (Editor), Shrimp and Prawn Farming in the Western Hemisphere. Dowden, Hutchinson, and Ross, Stroudsberg, PA, chapter II. Moav, R. and Wohlfarth. G.W., 1973. Carp breeding in Israel. In: R. Moav (Editor), Agricultural Genetics, John Wiley, New York. Monaco, G., 1975. Laboratory rearing of larvae of the palaemonid shrimp Macrobrachium americanum (Bate). Aquaculture 6: 369-375. Mulley, J.C. and Latter, D.H., 1980. Genetic variation and evolutionary relationships within a group of thirteen species of penaeid prawns. Evolution, 34 (5): 904-916. Nagabhushanam, R. and Kulkarni, G.K., 1981. Effect of exogenous testosterone on the androgenic gland and testis of a marine penaeid prawn, Parapenaeopsis hardwickii (Miers) (Crustacea, Decapoda, Penaeidae). Aquaculture, 23: 19-27. Nagamine, C., Knight, A.W., Maggenti, A. and Paxman, G., 1980a. Effects of androgenic gland ablation on male primary and secondary sexual characteristics in the Malaysian prawn, Macrobrachium rosenbergii (de Man) (Decapoda, Palaemonidae), with evidence of induced feminization in a nonhermaphroditic decapod. Gen. Comp. Endocrinol., 41: 423-441. Nagamine, C., Knight, A.W., Maggenti, A. and Paxman, G., 1980b. Masculinization of female Macrobrachium rosenbergii (de Man) (Decapoda, Palaemonidae) by androgenic gland implantation. Gen. Comp. Endocrinol., 41: 442-457. Nakamura, N. and Kasahara, S., 1955. A Study on the phenomenon of the tobi-koi or shoot carp. I. On the earliest stage at which the shoot carp appears. Bull. Jpn. Sot. Sci. Fish., 21 (2) (in Japanese). Translated in Bamidgeh, 29 (2): 41-44. Nakamura, N. and Kasahara, S., 1956. A study on the phenomenon of the tobi-koi or shoot carp. II. On the effect of particle size and quantity of the food. Bull. Jpn. SOC. Sci. Fish, 21 (9) (in Japanese). Translated in Bamidgeh, 29 (2): 45-47. Nakamura, N. and Kasahara, S., 1957. A study on the phenomenon of the tobi-koi or shoot carp. III. On the results of culturing the modal group and the growth of carp fry reared individually. Bull. Jpn. Sot. Sci. Fish, 22 (1) (in Japanese). Translated in Bamidgeh, 29 (2): 48-52. Nakamura, N. and Kasahara, S., 1961. A study on the phenomenon of the tobi-koi or shoot carp. IV. Effects of adding a small number of larger individuals to the experimental batches of carp fry and of culture density upon the occurrence of shoot carp. Bull. Jpn. Sot. Sci. Fish., 27 (11) (in Japanese). Translated in Bamidgeh, 29 (2): 53-56. Nei, M., 1972. Genetic distance between populations. Am. Nat., 106: 283-290. Nelson, K., 1977. Genetic considerations in selecting crustacean species for aquaculture. Proc. World Maricult. Sot., 8: 643-564. Nelson, K. and Hedgecock, D., 1976. Electrophoretic evidence on multiple paternity in the lobster, Homarus americanus (Mime-Edwards). Am. Nat., 3 (978): 361-365. Nelson, K. and Hedgecock, D., 1980. Enzyme polymorphism and adaptive strategy in the decapod crustacea. Am. Nat., 116 (2): 238-279.

409

Nelson, K., Hedgecock, D., Borgeson, W., Johnson, E., Dagget, R. and Aronstein, D., 1980. Density dependent growth inhibition in lobsters, Homarus (Decapoda, Nephropidae). Biol. Bull., 169: 162-176. Nelson, K., Hedgecock, D. and Borgeson, W., 1983. Photoperiodic and ecdysial control of vitellogeneses in lobsters (Homarus) (Decapoda, Nephropidae). Can. J. Fish. Aquat. Sci., in press. Niiyama, H., 1969. A comparative study of the chromosomes in Decapods, Isopods, Amphipods, with some remarks on cytotaxonomy and sex determination in Crustacea. Mem. Fat. Fish., Hokkaldo Univ., 7: l-60. Niiyama, H., 1962. On the unprecedently large number of chromosomes of the crayfish Astacus kowbridgre: Stimpson. Anim. Zool. Jpn., 36: 229-233. Niiyama, H., 1966. The chromosomes of two species of edible crabs (Brachyura, Decapoda, Crustacea). Bull. Fat. Fish. Hokkaido Univ., 16: 201-205. Prentice, E. and Rensel, J.E., 1977. Tag retention of the spot prawn, Pandalusplatyceros, injected with coded wire tags. J. Fish. Res. Board Can., 32 (11): 2199-2203. Rao, R.M., 1965. Breeding behavior in Macrobrachium rosenbergii (de Man). Fish. Technol. (India), 2 (1): 19-25. Rajyalakshimi, T., 1974. The freshwater prawn, Macrobmchium malcomsonii, for use in pond culture. Sea Food Export J., 6 (3): l-5. Ricker, W.E., 1976. Computation and interpretation of biological statistics for fish populations. Bull Fish. Res. Board Can., 191, 382 pp. Riek, E.G., 1959. The Australian freshwater Crustacea. In: Biogeography and Ecology in Australia. Monographiae Biol., 8: 246-268. Roberts, F.L., 1969. Possible supernumery chromosomes in the lobster, Homarus americanus. Crustaceana, 16: 194-196. Robertson, F.W., 1962. Changing the relative size of the body parts of Drosophila by selection. Genet. Res., 3: 169-180. Sanchez, C., 1979. Desarrollo larval de Macrobmchium tenellum en El Salvador. In: T.V.R. Pilay and W.A. Dill (Editors), Advances in Aquaculture, Fishing News Books Ltd., Farnham, England, pp. 311-313. Sandifer, P.A. and Lynn, J.W., 1980. Artificial insemination of caridean shrimp. In: W.A. Clark and T.S. Adams (Editors), Advances in Invertebrate Reproduction, Elsevier Scientific Publishing Co., New York, pp. 271-288. Sandifer, P.A. and Smith, T.I.J., 1979. A method for artificial insemination of Macrobmchium prawns and its potential use in inheritance and hybridization studies. Proc. World Maricult. Sot., 10: 403-418. Sandor, T., 1980. Steroids in invertebrates. In: W.H. Clark and T.S. Adams (Editors), Advances in Invertebrates Reproduction. Elsevier Scientific Publishing Co., New York, pp. 81-96. Sankolli, K.N., Shenoy, S., Jalihal, D.R. and Almelkar, G.B., 1982. Crossbreeding experiment with the giant freshwater prawn Macrobrachium rosenbergii and M. Malcomsonii. In: M.B. New (Editor), Giant Prawn Farming. Elsevier Scientific Publishing Company, Amsterdam, New York, pp. 91-98. Sarver, D., Malecha, S. and Onizuka, D., 1979. Development and characterization of genetic stocks and their hybrids in Macrobmchium rosenbergii: physiological responses and larval development rates. Proc. World Maricult. Sot., 10: 880-892. Shokita, S., 1973. Abbreviated larval development of the freshwater prawn Macrobrachium shokitai Fujino et Baba (Decapoda Palaemonidae) from Iriomete Island of the Ryukyus. Annot. Zool. Jpn., 46 (2): 111-126. Shokita, S., 1978. Larval development of interspecific hybrid between Macrobrachium asperulum from Taiwan and Macrobrachium shokitai from the Ryukyus. But Jpn. Sot. Sci. Fish., 44 (11): 1187-1195. Smith, P.J. and McKay, J.L., 1980. Genetic variation in the rock lobsters &us edwardsii and Jasus novaehollandiae. N.Z. J. Mar. Freshwater Res., 4 (1): 55-63.

410

Smith, T.I.J., Waltz, W. and Sandifer, P.A., 1980. Processing yields for Malaysian prawns and the implications. Proc. World. Maricult. Sot., 11: 556-568.

Smitherman,R.O., Moss, D.D. and Diaz, E.L., 1974. Observation of the biology of Mu-

crobrachium americanum from a pond environment in Panama. Proc. World Maricult. sot., 5: 29-40. Spurway, H., 1955. The causes of domestication: an attempt to integrate some ideas of Konrad Lorenz with evolution theory. J. Genet., 53: 325-362. Stelmach, D., 1980. Electrophoretic variation in Macrobmchium rosenbergii: evidence for subspecific variation. M.S. Thesis Report, Dept. of Genetics, University of Hawaii, Honolulu, HI. Strong, D.R., 1972. Life history variation among populations of an amphipod (Hyalella azteca). Ecology, 53 (6): 1103-1111. Strong, D.R., 1973. Amphipod amplexus: the significance of ecotypic variation. Ecology, 54 (6): 1383-1388. Tashian, R.E., 1966. Geographic variation in the respiratory metabolism and temperature coefficient in tropical and temperate forms of the fiddler crab, Uca pugna. Zoologica, 41: 39-47. Tave, D. and Brown, A., 1981. A new device to help facilitate manual spermatophore transfer in penaeid shrimp. Aquaculture, 25: 299-301. Templeton, W., 1935. Local differences in the body proportions of the lobster Homarus americanus. J. Biol. Board Can., 1 (B): 213-226. Tessier, G., 1936. Croissance comparee des formes locales d’une meme esp&ce. Mem. Mus. R. Hist. Bel., 2: 627-634. Thampy, D.M. and John, P.A., 1970. On the androgenic gland of the ghost crab Ocypoda platytarsis M. Edwards. Acta Zool. (Stockholm), 51: 203-210. Thampy, D.M. and John, P.A., 1973. Observations on variations in the male sex characters and their relation to the androgenic gland in the shrimp, Machrobrachium idae (Heller). Acta Zool. (Stockholm), 54: 193-200. Tracey, M.L., Nelson, K., Hedgecock, D., Shleser, R.A. and Pressick, M.L., 1975. Biochemical genetics of lobsters: genetic variation and the structure of American lobster (Homarue americanus) populations. J. Fish. Res. Board Can., 32: 2091-2101. Trudeau, T.N., 1978. Electrophoretic protein variation in Macrobrachium ohione and its implications in genetic studies. Proc. World Maricult. SOC., 9: 139-145. Vernberg, F.J., 1962. Comparative physiology: latitudinal effects on physiological properties of animal populations. Annu. Rev. Physiol., 24: 517-546. Waterman, T.H., 1960. The Physiology of Crustacea. Vol. I, Metabolism and Growth. Vol. II, Sense Organs, Integration and Behavior. Academic Press, New York, 670 PP. and 681 pp. Williams, G. and Needham, A.E., 1941. Metric variations in populations of Carcinus maenas. J. Mar. Biol. Assoc. (U.K.), 24: 261-281. Williamson, D.I., 1972. Larval development in a marine and freshwater species of Macrobrachium (Decapoda, Palaemonidae). Crustaceana, 23 (3): 282-298.

DISCUSSION

University of Houston: I would like to emphasize that there is no heterogenesus individual growth in most penaeids equivalent to that in Macrobrachium rosenbergii. Also there is little sexual dimorphism therefore I wouldn’t recommend monosex culture in penaeids. Also I think, since penaeid farming is expanding rapidly there is a bone fide need for genetic manipulation and you don’t need to single pair mate in order to do this; one

Jim Lester,

411

has to deal with the organism in the environment industry, i.e. one in which a mating tank contains

that will be utilized by the multiple individuals.

Winston Menzel, Florida State University, Tallahassee, FL: Despite the fact that the M. rosenbergii strain has undergone many generations under culture is there any indication of inbreeding, i.e. is the cultured strain still heterozyous? Mulecha: Electrophoretically,

yes.

Giora Wohlfarth, Dor Fish Culture Research Station, Israel: In your discussion of the size distribution of M. rosenbergii you emphasized only a second moment function, coefficient of variation. In the tobi koi (common carp) papers Nakamura and Kasahara (1955, 1956,1957,1961) used a third moment function - coefficient of skewness. Why don’t you use it? Mulecha: I don’t know. We could and I suppose we should. However, hetergeneous individual growth rate is so pronounced we pick it up with using only second moment functions. Graham Gall, University of California, Davis, CA: I hear more and more at crustacean discussions such as these about all the problems involved (your Table II) and I wonder If they’re really that severe. For example, if one needs genetic identification and there is no effective tag, then get on with it even if it means putting individuals in little boxes. Furthermore, I think there’s a role for genetics to play in developing an appreciation of the species per se. Mulecha: I feel most crustacean geneticists are doing exactly what you suggest - they’re moving forward regardless of the constraints. However, your point is well taken; some people are deterred by the problems of genetic manipulation in crustaceans. Roger Doyle, Dalhousie University, Halifax, N.S., Canada: I believe more sophisticated statistics could make up for some technical problems. For example, suppose we are interested in the question of whether a small animal before maturation is a small animal after maturation. One could more easily investigate this not with a tag identifying individuals but with a simpler tag and more sophisticated statistical techniques. One could put a simple mark on the bodies of small and large animals in a distribution at one point in time and work out a biserial correlation with the same animals in the distribution at a later time. This is almost as efficient as other correlations such as the Pearson Product moment correlation.

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techniques may Mulecha: I agree with you, Roger, more “sophisticated” help. For example, the relationship between a small animal before or after maturation could also be studied using electrophoretic marking. One could simply establish separate larval populations each uniquely marked electrophoretically - say AA, BB and CC, and then physically construct one larval population by simply combining different size classes of the marked batches. The constructed larval population would give rise to a PL population whose size classes would be marked electrophoretically and one could simply follow the population as it grows and matures. Arlene Longwell, National Marine Fisheries Service, Milford, CT: What kind of material is available for interspecific crossing in crustaceans? Mulecha: Holthius and Rosa (1965) and Holthius (1980) should be consulted to partially answer your question. A previous section (“species selection”) gives relevant references for penaeids. In lobsters it boils down to two species - H. gummarus and .H. homarus. There are several Macrobrachium species potentially valuable in intraspecific studies (Holthius, 1950, 1951, 1952; Ling and Costelleo, 1979). M. carcinus (Lewis, 1962, 1965; Lewis et al., 1966; Choudury, 1971a, b) and M. americanurn (Smitherman et al., 1974; Monaco, 1975) are found on the east and west coasts of Central and South America, respectively, and have large thick chelae and are aggressive. M. tenellum (Sanchez, 1979) and M. acanthurus (Choudhury, 1970, 1971c) are long, slender claw types similar to M. rosenbergii. Dobkin et al. (1974) were unsuccessful in hybridizing M. acanthurus and M. carcinus. M. malcomsonii is the next to largest Mucrobrachium after M. rosenbergii (Holthius, 1950). It is aquacultured and comprises a large fishery in India (Ibrahim, 1962; Rajyalakshimi, 1974). There is one report of successful hybridization between M. malcomsonii and M. rosenbergii (Sankolli et al., 1982). M. vollenhavenii a moderate-size prawn and M. macrobrachion a smaller species, are found in Central and West Africa where they comprise a fishery (Miller, 1971). M. australiense, M. hendersondayanum (Jalihal and Sankolli, 1975a, b) and M. sokitai (Shokita, 1973) are very small species but have extremely abbreviated larval development, a potentially useful characteristic (Dobkin, 1969). M. hendersonduyanum, for example, has one larval stage and M. australiense has four stages (Fielder, 1970). M. lar attains a moderate size but is very aggressive (Atkinson, 1977). M. cauernicola is a blind, albino species found in India (Kemp, 1924) and a number of interesting Macrobrachium species are found in Australia (Riek, 1959). In most cases the larval-rearing conditions for these species have been worked out and are similar to those for M. rosenbergii. Dick Koehn, State University of New York, Stoneybrook, NY: I have a question for Dr. Hedgecock; what is the economic picture of lobster broodstock development?

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Denis Hedgecock, University of California, Davis, CA: Husbandry of broodstock females is just a fraction of the total cost of a commercial lobster operation. Male&a: ly?

Can you artificially

spawn lobsters

and incubate

the eggs artificial-

Hedgecock: Some people have tried this but without much success. Our lab is interested in looking at this from the point of view of eliminating the entire brooding time. However, the female does a better job than a male at aerating and cleaning her eggs. Koehn’: A comment regarding the parallel Malecha drew in his review between population flushing (a la Carson, 1968,1975) and that which is occurring when Macrobrachium rosenbergii is brought under culture. The Carson founder-flush phenomenon is only conjectural. We have no evidence that such a situation occurs in nature during speciation or under culture. Moreover, the founder-flush phenomenon has limited credibility in evolutionary biology circles. Male&a: Yes, tion and the the need to domestication to aquaculture

I know. I drew the parallel between M. rosenbergii domesticaCarson founder-flush theory only to heuristically underscore think quantitatively about the long-term genetic effects of in aquaculture and to apply models developed in other fields species.

‘Comment and response communicated

after formal session.