Gordon, S.

Toller, W.

Aquatic Commons

Page 1040                 57th Gulf and Caribbean Fisheries Institute  
 
A Population Survey of the West Indian Topshell  
(Cittarium pica; Trochidae) in the U.S. Virgin Islands 
 
WES TOLLER1 and SHENELL GORDON2 
1Division of Fish and Wildlife 
45 Mars Hill 
Frederiksted, US Virgin Islands 00840 
2Division of Fish and Wildlife 
 6291 Estate Nazareth 
St. Thomas, US Virgin Islands 00802-1118, 
  
 
The West Indian topshell, Cittarium pica (Trochidae), is an intertidal 
gastropod that is commonly harvested for food throughout the Caribbean. In 
the U.S. Virgin Islands, Cittarium is caught by commercial, recreational and 
subsistence fishers. However little is known about Cittarium population 
structure, making it difficult to assess the impact of harvest upon local 
populations. In order to provide baseline data for fisheries management, we 
conducted intertidal surveys of Cittarium populations on St. Croix, St. John, 
St. Thomas, and associated offshore cays of the USVI. Our results showed 
considerable site-to-site variation in Cittarium population structure: average 
density and size varied both within and among islands. At most sites, larger 
adult Cittarium (> 62 mm shell width) were either rare or absent, and generally 
at densities of < 0.2 individual/m2.  Inaccessible sites and sites within no-take 
areas had higher densities of large Cittarium. These data suggests that harvest-
ing has impacted population size structure by removal of the largest individu-
als. The abundance of young-of-the-year Cittarium (< 10 mm shell width) 
varied substantially among sites, but high densities (> 10 individuals/m2) were 
not uncommon. This observation indicates that Cittarium recruitment levels 
may be relatively high but are spatially localized. We identify and discuss 
factors that may contribute to spatial variability in Cittarium population 
structure (e.g. substrate composition, habitat topography, exposure to wave 
action).  We conclude that harvesting and variable recruitment patterns are two 
of the most significant determinants of variable Cittarium size distributions in 
the USVI. 
 
KEY WORDS:  West Indian topshell, Cittarium, whelk, rocky intertidal, 
ecology, fishery 
 
Un Muestreo de la Población de Cittarium pica (Trochidae) en  
los Islas Virgenes de los EE.UU 
 
El caracol, Cittarium pica (Trochidae), también conocido como burgao, es 
un gastropod frecuentemente cosechado para comida en las aguas del caribe.  
En las islas Vírgenes de los Estados Unidos (USVI), el Cittarium se pesca para 
el comercio, recreación o para subsistencia.  Sin embargo, poco se conoce 
acerca de la estructura de las poblaciónes del Cittarium por lo que resulta 
  Abstracts of Poster Presentations  GCFI:57  (2006)             Page 1041  
 
difícil determinar el impacto que tiene la pesquería en las poblaciónes locales.  
De tal forma, hemos conducido estudios de las poblaciónes del Cittarium en 
las islas de Santa Cruz, Santo Tomas, San Juan y otros islotes pertenecientes a 
USVI.  Obtuvimos resultados bastante variados entre las distintas localidades: 
el tamaño y densidad promedio varia entre localidades y dentro de una misma 
localización.  En la mayoría de las localidades grandes Cittarium adultos (> 62 
mm achura máxima) eran poco común, y generalmente con densidades 
menores de 0.2 individual/m2.  En las áreas en que el acceso es prohibido o 
restringido hay mayor densidad de Cittarium grandes.  Estos datos indican que 
la pesquería ha impactado la estructura de la población del Cittarium por 
medio de la eliminación del individuo más grande.  La abundancia del 
Cittarium joven del año (<10 mm anchura máxima) vario substancialmente 
entre localidades, pero densidades altas (>10 individuos/m2) fueron común.  
Esta observación indica que los niveles del recrutamiento pueden ser relativa-
mente alto, pero estan localizado esparcidamente. Indentificamos y discutimos 
los factores ecológicas que pueden contribuir a los variables esparcidos en las 
poblaciónes del Cittarium (ej. composición física del suelo, topografia del 
habitat, y exposicion del movimiento de las olas). Concluimos que la pesquería 
y patrones de recruitamiento variadas son dos de los factores principales en la 
estructura de los poblaciónes del Cittarium en el USVI. 
 
PALABRAS CLAVES:  Caracol, Cittarium pica, estructura de las població-
nes,  pesquería 
 
 
Diagnostic  of  the  Recreational  Scuba  Diving  Activity in  
the  Marine  National  Park  of  Fernando  de  Noronha,  PE. 
 
FLÁVIA C. TONIOLI 1, EWERTON WEGNER2,  
OLDEMAR CARVALHO JR.3, and MARCUS POLETTE3 
2,3,4Universidade do Vale do ItajaiUnivali-CTTMAR 
Brazil 
 
 
This paper’s main goal is to characterize recreational SCUBA diving 
activity in Fernando de Noronha National Marine Park, located in Pernambuco, 
Brazil. To analyze SCUBA diving activity and the operating conditions of the 
scuba diving operators, a team from the laboratory of submarine diving from 
UNIVALI accompanied these divers while observing the following criteria: 
behavior of the divers during dives, observing whether organisms were 
touched or disturbed; the diver’s floatability and swimming skills; the condi-
tions of vessels used for scuba diving operations, and the availability of safety 
and live saving equipment. Each individual diver was profiled and their own 
level of satisfaction was evaluated via a semi-closed questionnaire. In addition, 
data on SCUBA diving impacts on the marine environment was obtained and 
divers were given an opportunity to suggest solutions for these impacts. During 
the expedition to Fernando de Noronha we observed increasing levels of 


A Population survey of the West Indian Topshell (Cittarium pica; Trochidae) in the U.S. Virgin Island [abstract of poster presentation]

http://aquaticcommons.org/14017/1/gcfi_57-99.pdf

A Population survey of the West Indian Topshell (Cittarium pica; Trochidae) in the U.S. Virgin Island [abstract of poster presentation]

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