Reproductive biology of the ghost crab, Ocypode rotundata Miers, 1882 (Decapoda, Ocypodidae) at Qeshm Island, Persian Gulf

Abstract

This study aimed to investigate some key aspects of the reproductive strategy ofOcypode rotundataMiers, 1882 from southwest beaches of Qeshm Island, Persian Gulf, Iran, by providing information regarding its sex ratio, sexual maturity, spawning period and fecundity. Samples were taken monthly, from February 2015 to January 2016. Size at the onset of morphometric maturity was estimated at 38.57 mm carapace width. The overall sex ratio (males/females) was observed as 1.13 : 1.00. On monthly based analyses, the sex ratio showed no significant differences, although a significant deviation was observed toward males in the larger size classes. According to the gonadosomatic index (GSI), gonad maturity and occurrence of ovigerous females, the main breeding season occurs from March to October, with a remarkable peak in June. Fecundity ranged from 24 152 to 10 5287 eggs per individual, with a mean value of 52 389 ± 25 660. The ratio between fecundity and carapace width varied from 632 to 2044 eggs/mm (mean: 1198 ± 472 eggs/mm) and fecundity relative to total mass varied from 771 to 1965 eggs/g (mean: 1336.66 ± 425.43 eggs/g). The reproductive output ranged from 1.04 to 3.78 (mean: 2.35 ± 0.90). The shape of the egg was spherical and it included 6 stages of growth, ranging from fully filled with yolk to fully occupied by the embryo. We concluded that reproduction inO. rotundatais seasonal, and that spawning occurs in an appropriate period to ensure maximum survival of the offspring. The fecundity ofO. rotundatais higher than that of other species of Brachyura, with GSI variations being related to temperature. Overall, the results of this study provide relevant information for the reproduction in general and the breeding seasons ofO. rotundata, whicht can be useful for conservation and management policies aimed at preserving the biodiversity of ghost crabs along the Persian Gulf’s sandy shores.

Fecundidade De Ucides Cordatus (Linnaeus, 1763) (Crustacea: Decapoda: Brachyura) No Norte Do Espírito Santo, Brasil

“…Fonte: Autores (2021) Modelos não-lineares, geralmente, representam bem a fecundidade dos crustáceos decápodes em função do tamanho e peso da fêmea (SILVA; OSHIRO, 2002;FERNANDES et al, 2010;JOAO;. Portanto, optou-se pelo modelo Potencial, amplamente utilizado na literatura, para avaliar a variabilidade da F em função das alterações em LC e P (PINHEIRO; TERCEIRO, 2000;SILVA;OSHIRO, 2002;FERNANDES et al, 2010;FAHIMI et al, 2017;JOAO;NADERI et al, 2018). Este modelo indicou que a fecundidade foi caracterizada pelo rápido aumento em função do incremento em tamanho e peso da fêmea (FIGURA 3) e, posteriormente, uma tendência assintótica.…”

Population, Reproductive and Fishery Dynamics of Spotted Box Crab (Calappa philargius), a New Claw-Only Fishery Species, in the Southern Taiwan Strait, China

“…However, it is unclear to what extent spawning takes place into May-July for all the aforementioned species, because the national annual summer fishing moratorium regulation typically disallows fishing and biological sampling. Some crabs demonstrate long spawning seasons, e.g., the ghost crab Ocypode retundata with one spawning season from May to October in the Persian Gulf (Naderi et al, 2018), and P. pelagicus from November through July in southeastern Australia (Johnson et al, 2010). For C. philargius, there could be a continuous spring-summerautumn spawning period (Figure 6).…”

The Ecology of Ocypode Rotundata (Miers, 1882) in Qeshm Island Persian Gulf

“…Warm conditions can induce optimal gonad growth, whereas a low temperature may delay egg development and larval release [6,7,22]. According to Persian Gulf temperature conditions, O. rotundata is actively breeding from March to October [23].…”

“…The eggs of O. rotundata are spherical in shape which includes six developmental stages with different color patterns: yellow, pale orange, orange, dark orange, brownish, brown color [23]. The variation in color during egg development is due to differences in absorption of the yolk reserves.…”

“…The variation in color during egg development is due to differences in absorption of the yolk reserves. Like other ghost crabs [22,[24][25][26], Ovigerous females of O. rotundata usually are scarce on the beach surface [23]. An admissible explanation for the low number of ovigerous female crabs could be the fact that they hide inside their deep burrows, incubating their eggs, until the appropriate time of hatching.…”