Marine Pollution Bulletin Vol. 38, No. 12, pp. 1227±1231, 1999 Ó 1999 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0025-326X(99)00167-8 0025-326X/99 $ - see front matter Imposex in Three Marine Gastropod Species in Chile and Potential Impact on Muriciculture MEREDITH GOODING *, CARLOS GALLARDOà and GERALD LEBLANC Department of Toxicology, North Carolina State University, Raleigh, NC 27695-7633, USA àInstituto de Zoologõa, Universidad Austral de Chile, Valdivia, Chile A survey of imposex was conducted between the Bay of Mediterranean (Gibbs et al., 1987; Tan 1997; Smith, San Vicente, Concepcion, Chile (36° 500) and the Bay of 1981; Wilson et al., 1993; Axiak et al., 1995) indicate the Renocavi, Puerto Montt, Chile (41° 350), to determine if global nature of this phenomena but to our knowledge imposex is occurring in an area of collection and cultiva- no surveys of imposex have been conducted on the Pa- tion of the gastropod, Chorus giganteus. Imposex was ci®c Coast of South America. Imposex is causally as- recorded in three chilean muricids C. giganteus, Xantho- sociated with tributyltin (TBT), a component of marine chorus cassidiformis and Nucella crassilabrum complex. anti-fouling paints, and can be induced in neogastopod Percentage of imposex in females sampled ranged from and mesogastropod species at concentrations as low as 0% to 100%. The degree of expression of imposex was 0.5 ng/l (Bryan et al., 1986). The eects of this com- not so severe as to elicit sterility in the individuals sur- pound on non-target organisms were ®rst noted in veyed. Incidence of imposex was as high as 47% in areas oysters in France in the 1970s and were linked to de- of harvest of C. giganteus for reproductive and cultivation velopment of a penis-like outgrowth in female gastro- studies for commercial production of this species. A six pods in the early 1980s (Alzieu, 1991; Smith, 1981). percent incidence of imposex was observed in Nucella Incidence of imposex is correlated to ambient water proximal to the facility for cultivation of C. giganteus. TBT concentration with higher induction linked to Gastropods of the genus Nucella are used in other coun- yacht docking facilities, ship repair docks and marine tries to monitor incidence of imposex and have demon- trac (Smith, 1981; Gibbs et al., 1987). The use of TBT strated sensitivity toward tributyltin (TBT), the associated is prohibited or severely restricted in some countries but causal agent. Since sex of individuals in muriciculture is there is no uniformity of regulations worldwide and determined by the presence or absence of a penis, imposex TBT use continues. may lead to erroneous classi®cation of males and females. Imposex is a graded response with greater penis and The incidence and severity of imposex in C. giganteus and vas deferens development associated with higher related species may have a negative impact on sustainable concentrations of TBT (Bettin et al., 1996). In some cultivation and harvest of gastropods in Chile. Ó 1999 species such as Nucella lapillus, found in Great Britian, Elsevier Science Ltd. All rights reserved. imposex has resulted in local population declines (Gibbs and Bryan, 1986). In this species the growth of the vas Keywords: imposex; gastropod; tributyltin; Chile; Chorus deferens blocks the ovipore of the female preventing giganteus; Nucella. release of egg capsules from the capsule gland. In Ocenebra erinacea, the morphological response to TBT is manifest as a split bursa copulatrix and capsule gland (Gibbs et al., 1990). These species and related gastro- Introduction pods are used to monitor TBT levels in countries where use of TBT anti-fouling paints are regulated. In other Imposex (Smith, 1971) or pseudohermaphrodatism, the stenoglossans such as Ilyanassa obsoleta, reproductive superimposition of male characteristics such as a penis ®tness of the population is seemingly unaected and vas deferens on female dioecious gastropods is a although a penis, vas deferens, and convoluted oviduct widespread phenomena in the marine environment. are present (Smith, 1981). Imposex is currently documented in over 118 species in Gastropods of the genus Nucella have demonstrated 63 genera worldwide (Bettin et al., 1996). Data from sensitivity to imposex and have previously been used as Europe, Asia, North America, Australia, and the biomonitors for TBT levels in the marine environment (Gibbs and Bryan, 1986; Bright and Ellis, 1990). In *Corresponding author. southern Chile, populations of the Nucella crassilabrum 1227 Marine Pollution Bulletin complex are distributed throughout the intertidal rocky The purpose of this study was to determine if imposex shore. Chile has an extensive coastline over 4200 km is occurring in three marine gastropod species in Chile to long, with over 602 species of gastropods including some a degree that may adversely impact cultivation and 40 nominal muricean species (Ramirez, 1998). Muricids harvest of commercially important species. including Concholepas concholepas, Thais chocolata, and C. giganteus are harvested for local consumption and Materials and Methods export. Excessive harvesting of C. concholepas has led to legal measures to control this threatened mollusc and The Muricidae, N. crassilabrum, X. cassidiformis, and has increased pressure on other species with potential C. giganteus were collected between February and May, commercial value such as X. cassidiformis and Trophon 1998, from selected sites between the Bay of San Vi- geversianus. cente, Concepcion, (36° 500) (Region IX, Chile) and the Eorts are currently underway to develop sustainable Bay of Renocavi (Metri) Puerto Montt, (41° 360) (Re- cultivation methods for C. giganteus in Chile. One gion X, Chile) (Fig. 1). Each site was classi®ed as an component of the cultivation of muricid gastropods or enclosed bay or open coast and predominate land use muriciculture, is to develop extensive knowledge of the was noted to determine proximity to industry and har- reproductive cycles and life history of this species to bors (Table 1). Areas of high boating activity were optimize production. In muriciculture of C. giganteus, harbors with more than ten ships within visible range of sex determination is based on the presence or absence of the site. Medium boating activity was considered an a penis. If imposex is occuring in areas where gastropods area where less than ten ships were in proximity to the are being collected for cultivation, females may be mis- site or where there are harbor facilities for docking of identi®ed as males and prove detrimental to reproduc- large ships. In the medium boating activity areas, ar- tive studies and commercial production of C. giganteus. tesanal ®shing was frequent. Low shipping activity was a Fig. 1 Location of sampling sites for the imposex survey. The muriciculture facility is indicated on the map as a star. 1228 Volume 38/Number 12/December 1999 TABLE 1 Site characteristics and sampling dates of imposex survey at eleven sites on the coast of Chile. Site Coordinates Species sampled Date sampled Site characterization Lenga 36° 40 S 71° 53 W X. cassidiformis 5/15/98 Open coast, high boating activity, industrial Concepcion 36° 48 S 73° 10 W N. crassilabrum 3/28, 5/11/98 Open coast, high boating activity, industrial Maule 36° 50 S 73° 10 W N. crassilabrum 5/30/98 Open coast, high boating activity, industrial Mancera 39° 55 S 73° 23 W C. giganteus 3/23/98 Bay, medium boating activity, rural Corral 39° 05 S 73° 25 W C. giganteus 4/15/98 Bay, medium boating activity, rural X. cassidiformis 4/15/98 Chaihuin 39° 56 S 73° 37 W C. giganteus 4/2/98 Bay, low boating activity, rural San Carlos 39° 15 S 73° 26 W N. crassilabrum 3/9/98 Bay, medium boating activity, rural Metri 41° 36 S 72° 43 W N. crassilabrum 2/10/98, 3/4/98 Bay, medium boating activity, rural Carelmapu 41° 44 S 73° 44 W N. crassilabrum 3/11/98 Open coast, medium boating activity, rural Guar 41° 40 S 73° 59 W N. crassilabrum 4/28/98 Bay, medium boating activity, rural Caicaen 41° 47 S 73° 11 W N. crassilabrum 3/15/98 Bay, medium boating activity, rural rural area with no shipping observed and limited artes- Animals were held no more than seven days before anal ®shing. processing. Shell length and shell height were measured The classi®cation of Nucella in Chile is controversial to the nearest 0.1 mm using vernier calipers. Snails were so for the purposes of this survey all Nucella were opened with a hammer and soft tissue mass was weighed grouped together as ``Nucella crassilabrum'' complex. to the nearest 0.01 g. Snails were sexed based on the Nucella were collected at low tide from the intertidal presence of the reproductive glands (albumen gland, zone. X. cassidiformis and C. giganteus were collected sperm-ingesting gland and capsule gland in females, from the subtidal zone by divers at depths from 5 to 20 prostate gland in males). Juveniles and parasitized in- m. When possible, the three species were collected from dividuals were excluded from analyses of imposex inci- the same site. If available, 40 or more adults were col- dence. lected from each site (Table 2). An eort was made to The presence or absence of a penis in adults was noted collect all species during their reproductive season. and penis length was measured to the nearest 0.1 mm Nucella were also collected from Metri, the location of using a micrometer graticle (0±10 mm). Penis length was the Center of Aquaculture and Marine Sciences (CEA- measured from the side of the right tentacle where the CIMA) of University of Los Lagos where cultivation of penis joins the body to the tip. Measurements were C. giganteus is currently underway (Fig.