Interpopulational differences in the female reproductive cycle of the southwestern Atlantic estuarine crab &lt;i&gt;Chasmagnathus granulatus Dana&lt;/i&gt;, 1851 (Brachyura: Grapsoidea: Varunidae)

Romina B Ituarte,Eduardo D Spivak,Tomás A Luppi,Claudia Bas

doi:10.3989/scimar.2006.70n4709

Abstract

The female reproductive biology of Chasmagnathus granulatus Dana, a semiterrestrial burrowing crab endemic to the southwestern Atlantic, was compared in two contrasting coastal habitats: San Antonio (SA, marine) and Mar Chiquita (MC, estuarial). Mature females were collected monthly for 1.5 years and the ovarian cycle was described using a qualitative scale. Gonadosomatic (GSI) and hepatosomatic (HSI) indexes were calculated. The highest GSI and HSI occurred early in the reproductive season in SA and during the non-reproductive season in MC. The beginning and duration of the reproductive season also differed between populations: it started later and was shorter in SA. In MC, secondary vitellogenesis continued when the reproductive season had finished, and the ovaries remained fully developed throughout the non-reproductive season (winter). Therefore, females of MC were ready to lay eggs as soon as spring environmental conditions appeared. However, SA females did not attain a fully developed ovary during winter. A limited food supply would restrict the available energy to complete secondary vitellogenesis at the end of the reproductive season in SA, after the last spawning. Thus, the vitellogenic cycle should be completed in the following spring, causing a delay in the beginning of the reproductive period. In addition, the higher temperature amplitude may cause the reproductive period in SA to end early.

Highlights

Initial growth and development of crab oocytes is based on autochthonous material but subsequent growth involves the contribution of allochthonous material (Nelson, 1991); at least in some species, reserves stored in the hepatopancreas are mobilized to the ovary during secondary vitellogenesis (Pillay and Nair, 1973; Kyomo, 1988; see Li et al, 2006 for complete references)
In Mar Chiquita (MC), secondary vitellogenesis continued when the reproductive season had finished, and the ovaries remained fully developed throughout the nonreproductive season
Initial growth and development of crab oocytes is based on autochthonous material but subsequent growth involves the contribution of allochthonous material (Nelson, 1991); at least in some species, reserves stored in the hepatopancreas are mobilized to the ovary during secondary vitellogenesis (Pillay and Nair, 1973; Kyomo, 1988; see Li et al, 2006 for complete references)

Summary

Introduction

Initial growth and development of crab oocytes is based on autochthonous material (primary vitellogenesis) but subsequent growth involves the contribution of allochthonous material (secondary vitellogenesis) (Nelson, 1991); at least in some species, reserves stored in the hepatopancreas are mobilized to the ovary during secondary vitellogenesis (Pillay and Nair, 1973; Kyomo, 1988; see Li et al, 2006 for complete references). Multiple broods may be produced during an intermolt period (Morgan et al, 1983), and females develop a new cohort of oocytes as soon as a clutch is extruded. Ovigerous females of these crabs may have ovaries either in primary or secondary vitellogenesis. Secondary vitellogenesis of the second cohort is nearly complete, so a new clutch may soon be extruded. The last cohort of oocytes of the current season may arrest their development at the end of primary vitellogenesis and a premolt process begins (Nelson, 1991). It is possible to detect several ovarian cycles during the reproductive season in a population by observing successive peaks in the proportion of both females with ripe ovaries and ovigerous females Each ovarian cycle may be described by taking into account the changes in size and colour during oocyte development (e.g. Simons and Jones, 1981; Abelló 1989; González-Gurriarán et al, 1993; Rodríguez et al, 1997; Yamaguchi, 2001a)

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