Abstract
The Patagonian squid, Loligo gahi D’Orbigny, has been described as having temporally and spatially identifiable spawning aggregations. Variation at six microsatellite loci was used to assess whether seasonal and geographical spawning groups around the Falkland Islands represent distinct sub-populations. Genetic variation at these loci is high in this species (mean expected heterozygosity=0.87; mean number of alleles=14.7). No evidence of significantly different allele frequencies was found, either between samples from putative spawning cohorts or geographical areas, indicating that L.gahi around the Falkland Islands comprise a single genetically homogeneous population. Age structure analysis of samples (from statolith growth increments) indicated substantial spread in hatching dates among individuals of similar size and maturity status, suggesting the potential for extensive interbreeding between seasonal cohorts. A sample of L.gahi from the SE Pacific (Peru) displayed distinctly different gene frequencies (and allele size distribution at one locus) from SW Atlantic samples, supporting the suggestion that SE Pacific and SW Atlantic populations may represent distinct subspecies.
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Adcock GJ, Shaw PW, Rodhouse PG, Carvalho GR (1999) Microsatellite analysis of genetic diversity in the squid Illex argentinus during a period of intensive fishing. Mar Ecol Prog Ser 187:171–178
Agnew DJ, Nolan CP, des Clers S (1998) On the problem of identifying and assessing populations of Falkland Island squid Loligo gahi. S Afr J Mar Sci 20:59–66
Arkhipkin AI (1991) Methods for cephalopod age and growth studies with emphasis on statolith ageing techniques. In: Jereb P, Ragonese S, Boletzky S von (eds) Squid age determination using statoliths. NTR-ITPP Special Publication 1: 11-17
Arkhipkin AI, Middleton DAJ (2003) In-situ monitoring of the duration of embryonic development in the squid Loligo gahi (Cephalopoda: Loliginidae) on the Falkland shelf. J Mol Stud 69:123–133
Arkhipkin AI, Laptikhovsky VV, Middleton DAJ (2000) Adaptations for the cold water spawning in squid of the family Loliginidae: Loligo gahi around the Falkland Islands. J Mol Stud 66:551–564
Augustyn CJ, Grant WS (1988) Biochemical and morphological systematics of Loligo vulgaris vulgaris Lamarck and Loligo vulgaris reynaudii D’Orbigny Nov. Comb. (Cephalopoda: Myopsida). Malacologia 29:215–233
Balloux F, Lugon-Moulin N (2002) The estimation of population differentiation with microsatellite markers. Mol Ecol 11:155–165
Boyle PR (1983) Cephalopod life cycles, vol I. Species accounts. Academic Press, London
Boyle PR, Boletzky Sv (1996) Cephalopod populations: definitions and dynamics. Philos Trans R Soc Lond B 351:985–1002
Boyle PR, Pierce GJ, Hastie LC (1995) Flexible reproductive strategies in the squid Loligo forbesi. Mar Biol 121:501–508
Brierley AS, Thorpe JP (1994) Biochemical genetic evidence supporting the taxonomic separation of Loligo gahi from the genus Loligo. Antarct Sci 6:143–148
Brierley AS, Rodhouse PG, Thorpe JP, Clarke MR (1993) Genetic evidence of population heterogeneity and cryptic speciation in the ommastrephid squid Martialia hyadesi from the Patagonian Shelf and the Antarctic Polar Frontal Zone. Mar Biol 116:593–602
Brierley AS, Thorpe JP, Pierce GJ, Clarke MR, Boyle PR (1995) Genetic variation in the neritic squid Loligo forbesi (Myopsida: Loliginidae) in the northeast Atlantic Ocean. Mar Biol 122:79–86
Carvalho GR, Loney KH (1989) Biochemical genetic studies on the Patagonian squid Loligo gahi d’Orbigny. I. Electrophoretic survey of genetic variability. J Exp Mar Biol Ecol 126:231–241
Carvalho GR, Nigmatullin CM (1998) Stock structure analysis and species identification. In: Rodhouse PG, O’Dor R (eds) Illex recruitment dynamics. FAO, Rome
Carvalho GR, Pitcher TJ (1989) Biochemical genetic studies on the Patagonian squid Loligo gahi d’Orbigny. II. Population structure in Falkland waters using isozymes, morphometrics and life history data. J Exp Mar Biol Ecol 126:243–258
Carvalho GR, Thompson A, Stoner AL (1992) Genetic diversity and population differentiation of the shortfin squid, Illex argentinus in the south-west Atlantic. J Exp Mar Biol Ecol 158:105–121
Goudet J (1995) Fstat (version 1.2): a computer program to calculate F-statistics. J Hered 86:485–486
Grant WS, Bowen BW (1998) Shallow population histories in deep evolutionary lineages of marine fishes: insights from sardines and anchovies and lessons for conservation. J Hered 89:415–426
Hatfield E, des Clers S (1998) Fisheries management and research for Loligo gahi in the Falkland Islands. CalCOFI Rep 39:81–91
Jackson GD (1994) Application and future potential of statolith increment analysis in squids and sepioids. Can J Fish Aquat Sci 51:2612–2625
Lipinski MR (1979) Universal maturity scale for the commercially important squid (Cephalopoda: Teuthoidea). The results of maturity classifications of the Illex illecebrosus (LeSueur, 1821) populations for the years 1973–1977. ICNAF Res Doc 79/II/38
Lipinski M, Durholtz MD, Underhill LG (1998) Field validation of age readings from the statoliths of chokka squid Loligo vulgaris reynaudii d’Orbigny 1845 and an assessment of associated errors. ICES J Mar Sci 55:240–259
Nesis KN (1987) Cephalopods of the world. TFH, Neptune City, N.J.
Nevo E (1978) Genetic variation in natural populations: patterns and theory. Theor Popul Biol 13:121-177
O’Connell M, Dillon MC, Wright JM, Bentzen P, Merkouris S, Seeb J (1998) Genetic structuring among Alaskan Pacific herring (Clupea pallasi) populations identified using microsatellite variability. J Fish Biol 53:150–163
Patterson KR (1988) Life history of Patagonian squid Loligo gahi and growth parameter estimates using least-squares fits to linear and von Bertalanfy models. Mar Ecol Prog Ser 47:65–74
Pérez Losada M, Guerra A, Carvalho GR, Sanjuan A & Shaw PW (2002) Fine population structuring of the cuttlefish Sepia officinalis (Mollusca: Cephalopoda) around the Iberian peninsula revealed by microsatellite DNA markers. Heredity 89:417–424
Raymond M, Rousset F (1995) GENEPOP (Ver. 1.2) -population genetics software for exact tests and ecumenicism. J Hered 86:248–249
Reichow D, Smith MJ (1999) Highly variable microsatellites in the California market squid Loligo opalescens. Mar Biotech 1:403–406
Reichow D, Smith MJ (2001) Microsatellites reveal high levels of gene flow among populations of the California squid Loligo opalescens. Mol Ecol 10:1101–1110
Rice WR (1989) Analyzing tables of statistical test. Evolution 43:223–225
Ruzzante DE, Taggart CT, Cook D (1998) A nuclear DNA basis for shelf- and bank-scale population structure in NW Atlantic cod (Gadus morhua): Labrador to Georges Bank. Mol Ecol 7:1663–1680
Shaw PW (1997) Polymorphic microsatellite markers in a cephalopod: the veined squid Loligo forbesi. Mol Ecol 6:297–298
Shaw PW, Adcock GJ (2002) Polymorphic microsatellite DNA markers for the Patagonian squid, Loligo gahi (Cephalopoda). Molecular Ecol Notes 2:331–333
Shaw PW, Pierce G, Boyle PR (1999) Subtle population structuring within a highly vagile marine invertebrate, the Veined squid Loligo forbesi (Cephalopoda: Loliginidae) uncovered using microsatellite DNA markers. Mol Ecol 8:407–417
Slatkin M (1995) A measure of population subdivision based in microsatellite allele frequencies. Genetics 139:457–462
Waples RS (1998) Separating the wheat from the chaff: patterns of genetic differentiation in high gene flow species. J Hered 89:438–450
Weir BS, Cockerham CC (1984) Estimating F-statistics for the analysis of population structure. Evolution 38:1358–1370
Winnepenninckx B, Backeljau T, Dewachter R (1993) Extraction of high molecular-weight DNA from molluscs. Trends Genet 9:407
Wirth T, Bernatchez L (2001) genetic evidence against panmixia in the European eel. Nature 409:1037–1040
Wright S (1969) Evolution and genetics of populations, Vol. 2. The theory of gene frequencies. University of Chicago Press, Chicago
Yeatman J, Benzie JAH (1994) Genetic structure and distribution of Photololigo spp. in Australia. Mar Biol 118: 79–87
Acknowledgements
This study was funded by the Falkland Islands Government. We thank the FIFD observers for help in collecting samples, and Director of Fisheries, John Barton, for supporting this work. The work carried out during this study was conducted in compliance with UK and Falkland Islands law.
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Contributed by J.P. Thorpe, Port Erin
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Shaw, P.W., Arkhipkin, A.I., Adcock, G.J. et al. DNA markers indicate that distinct spawning cohorts and aggregations of Patagonian squid, Loligo gahi, do not represent genetically discrete subpopulations. Marine Biology 144, 961–970 (2004). https://doi.org/10.1007/s00227-003-1260-z
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DOI: https://doi.org/10.1007/s00227-003-1260-z