On the Reproductive Cycle and Breeding Habits of Two Western Species of Haliotis ,

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“…Usually, a drastic decrease in a reproductive index is interpreted as spawning occurrence (Boolotian et al, 1962). Most indices evaluated in this study consistently showed up-down trends, with notable reductions during or on late autumn-winter period (September to February), suggesting the occurrence of spawning, and coinciding with the spawning temporality documented by Sevilla (1971) (Boolootian, 1962) , GAIA-Gonad area index, MGI-Gonadic index of calculated mass, * statistically significant correlation In spring-summer (march-august), indices showed two different trends: maintaining (IG and MGI) and increasing (GAIA and GIB). During this period, no spawning activity has been confirmed (Sevilla, 1971;Vélez-Arellano et al, 2016).…”

“…Reproductive indices.-Reproductive indices provide indirect information that allows to evaluate the reproductive condition, and are commonly used as tools to evaluate gonadal development and determine the timing of reproductive activity (Boolootian et al, 1962;Litaay and De Silva, 2002;Morais et al, 2003;Najmudeen and Victor, 2004;Najmudeen, 2007;Abidli et al, 2012;Elhasni et al, 2013). Usually, a drastic decrease in a reproductive index is interpreted as spawning occurrence (Boolotian et al, 1962).…”

“…In this regard, it is important to review, test and define the available options for estimating MI. In haliotids, these indices have been used primarily to evaluate the reproductive status of populations (Boolootian et al, 1962;Webber and Giese, 1969;Poore, 1973;Ault, 1985;Capinpin et al, 1998;Counihan et al, 2001;Litaay and De Silva, 2002;Najmudeen and Victor, 2004;Setyono, 2006). The simplest indicator is calculated by dividing the gonad weight by the total weight of the body, and it is commonly used in haliotids (Setyono, 2006) and other gastropods (Zetina et al, 2000;Morais et al, 2003;Abidli et al, 2012).…”

“…The simplest indicator is calculated by dividing the gonad weight by the total weight of the body, and it is commonly used in haliotids (Setyono, 2006) and other gastropods (Zetina et al, 2000;Morais et al, 2003;Abidli et al, 2012). The indices most commonly used are those that evaluate gonadal maturity based on the cross-sectional area occupied by the hepatic glandgonad complex (HGGC) in relation to either total shell length (Boolootian et al, 1962;Gurney and Mundy, 2004) or total area (Newman, 1967). Other indices evaluate gonadal volume in the HGGC relative to the specimen's weight (Ault, 1985;Lleonart, 1992).…”

Variation in biochemical composition during gonad maturation of the tropical abaloneHaliotis variaLinnaeus 1758 (Vetigastropoda: Haliotidae)

“…The digestive gland crosssection area of abalone usually remains constant throughout the year as compared with the gonad section area, which fluctuates from month to month according to their annual reproductive cycle. However, many studies have reported that the digestive gland will increase in size corresponding to the decrease in the size of the gonad, suggesting that material might be transported from the digestive gland to the gonad (Boolootian et al 1962;Litaay & De Silva 2003). Such transfer of nutrients from storage or digestive sites to the gonad has been inferred or demonstrated in a number of other groups of molluscs, including bivalve species (Ansell 1974;Gabbott 1975;Le Pennec et al 1991).…”