Some reproductive aspects of the areolate grouper, Epinephelus areolotus from the Gulf of Suez

Osman, Alaa G. M.; El-Ganainy, Azza A.; Abd-Allah, Ezzat

doi:10.1016/j.ejar.2018.02.002

Cited by 14 publications

(10 citation statements)

References 10 publications

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“…These conditions have increased the pressure on grouper populations in Kwandang Bay. Without management interventions by the government, the future of grouper stocks in the Bay can be considered under threat, especially as groupers, in general, are considered to have relatively low resistance and resilience to high levels of fishing pressure (Brunel and Piet 2013;Osman et al 2018).…”

Section: Discussionmentioning

confidence: 99%

Population dynamics of reef fish in the Kwandang Bay, Sulawesi Sea, Indonesia

et al. 2022

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Abstract. Achmad DS, Gani S, Ardiansyah W, Mokoginta MM, Nurdin MS, Jompa J, Indrianti MA, Achmad N. 2022. Population dynamics of reef fish in the Kwandang Bay, Sulawesi Sea, Indonesia. Biodiversitas 23: 5217-5226. The grouper stocks in Kwandang Bay, Sulawesi Sea, Indonesia, are dominated by orange-spotted grouper (Epinephelus coioides) and coral trout (Plectropomus leopardus). However, the Kwandang Bay grouper fishery is currently experiencing serious challenges due to population decline resulting in a decline in both the average size of fish caught and the production volume. This study was conducted in Kwandang Bay, Sulawesi Sea, from January to December 2021. The population dynamics parameters estimated were growth, recruitment, mortality, exploitation rate and yield per recruit. The results showed that the total length (TL) of E. coioides and P. leopardus ranged from 16.50-101 cm and 17.90-60 cm, respectively, with Von Bertalanffy K-coefficients of 0.38 and 0.69, respectively. Recruitment occurred during most of the year, with respective recruitment value ranges of 0.99-17.11% and 0.08-19.22%. Natural and fishing mortality was 0.69/year-1 and 0.87/year-1 for E. coioides, 1.16/year-1 and 1.47/year-1 for P. leopardus. Beverton and Holt yield per recruit analysis indicated recruitment overfishing of both E. coioides and P. leopardus. Fishing regulations are needed to maintain a sustainable grouper fishery, including a 25% reduction in fishing vessels and gear, to enable the groupers of Kwandang Bay to spawn at least once during their life cycle.

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Section: Discussionmentioning

confidence: 99%

Population dynamics of reef fish in the Kwandang Bay, Sulawesi Sea, Indonesia

et al. 2022

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“…Scale reading has been used to estimate ages in an assessment of inshore commercial species in the Red Sea (Mahmoud et al, 2009); and Darar (1994) used length frequency analysis to derive estimates of von Bertalanffy growth parameters. Aspects of reproduction such as spawning period, maturity, fecundity and sex ratio have been reported in studies by Mahmoud (2009), Ahmad et al (2011), Abdul Kadir et al (2016) and Osman et al (2018) in the Red Sea, Arabian Gulf and Malaysia. Differences in age and reproductive parameters between these studies may be attributable to regional variations, but could also be attributable to the methods and techniques used to formulate results.…”

Section: Introductionmentioning

confidence: 84%

“…Reproductive studies on this species in other locations have reported a range of estimates of maturity. In New Caledonia, Loubens (1980a) reported sexual maturation in females at 190 mm SL and an age of 2+; Abdul Kadir et al (2016) reported an L mat 50 for females of 326 and 357 mm L T within two regions of Malaysia; and in the Red Sea, Mahmoud (2009) reported female maturity at 235 mm L T after the second year of life in Egypt, and Osman et al (2018) reported female maturity at 255 mm L T and 2.23 years from the Gulf of Suez. These differences in the estimates of maturity could be the result of regional variation; they may also be the result of inconsistent methodologies when identifying and determining female gonadal stages, and/or in association with using different procedures for the calculation of female maturity schedules.…”

Section: Mortality and Age-based Selectivitymentioning

confidence: 99%

Age, growth and reproductive life‐history characteristics infer a high population productivity for the sustainably fished protogynous hermaphroditic yellowspotted rockcod (Epinephelus areolatus) in north‐western Australia

Boddington

Wakefield

Fisher

et al. 2021

Journal of Fish Biology

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The yellowspotted rockcod, Epinephelus areolatus, is a small-sized grouper that is widely distributed throughout the Indo-Pacific, where it forms a valuable component of the harvest derived from multispecies fisheries along continental and insular shelves. Samples of E. areolatus were collected from 2012 to 2018 from commercial catches and research surveys in the Kimberley, Pilbara and Gascoyne regions of north-western Australia to improve the understanding of the life history, inherent vulnerability and stock status of this species. Histological analysis of gonads (n = 1889) determined that E. areolatus was a monandric protogynous hermaphrodite. Non-functional spermatogenic crypts were dispersed within the ovaries of 23% of mature functioning females; nonetheless, these crypts were not observed during the immature female phase. The length and age at which 50% of females matured were 266 mm total length (L T ) and 2.7 years, respectively. The spawning period was protracted over 10-12 months of the year with biannual peaks at the start of spring and autumn (i.e., September and March) when the photoperiod was at its mid-range (i.e., 12.1 h).Estimates of the lengths and ages at which 50% of E. areolatus change sex from female to male were very similar (i.e., <5% difference) between the Kimberley and Pilbara regions, i.e., L sc 50 of 364 and 349 mm L T and A sc 50 of 7.9 and 7.3 years, respectively. A maximum age of 19 years was observed in all three regions, but there was significant regional variation in growth. These variations in growth were not correlated with latitude; instead a parabolic relationship was evident, where the smallest mean length-at-age and fastest growth rates (k) occurred in the mid-latitudes of the Pilbara region. In the Kimberley and Pilbara regions, individuals were not fully selected by commercial fish traps until 5-6 years of age, hence, several years after reaching maturity. These lifehistory characteristics infer a high population productivity, which underpins the sustainable harvest of this species, despite comprising the largest catches of all epinephelids in the multispecies tropical fisheries across north-western Australia.

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“…In fact, it is stated that this grouper fish in the Red Sea length below 20.2 cm is immature and length above 24.7 cm has matured with the first length at mature the female gonad ripe is 23.5 cm (Mahmoud, 2009). Furthermore, a recent study in Suez Bay showed that females under 18 cm were still immature (Osman et al, 2018), whereas mature gonads were found to be more than 32 cm with a minimum length of mature gonads of 25.5 cm. So, from the comparative data it can be estimated that the length first at capture in Arafura includes fish that have experienced gonad maturity.…”

Section: Length Frequencymentioning

confidence: 98%

The Fishing Ground of Bottom Longline Vessels and Exploitation Rate of Tiger Grouper (<i>Epinephelus aerolatus</i>) in Arafura Waters

et al. 2020

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As excessive capture activity adversely impacts fisheries sector, fish resources management is a necessity. This study was conducted as a scientific contribution for the managements of bottom longline fisheries in Arafura Waters and areolate grouper (Epinephelus areolatus) as one of the target catches. It was carried out from February to December 2017 and in November 2018. Data on the fishing grounds of eight bottom longline vessels were obtained from the vessel monitoring system (VMS) of Probolinggo Marine and Fisheries Resources Supervisory Unit, Mayangan Probolinggo Fishing Port, and Marine and Fisheries Resources Surveillance (PSDKP) Tual Station. Based on the analysis of the coordinates from the VMS, the fishing grounds of the bottom longline vessels in Arafura waters were found around Dolak until the border with Merauke and around Timika until Aru Islands. The composition of dominant catches consisted of croaker (Pennahia spp.) and snapper (Lutjanus spp.), as well as grouper (Epinephelus spp.) in a smaller proportion. The size structure of the areolate grouper caught with bottom longlines was 21.5–54.5 cmTL; its length at first capture (Lc) was 33.9 cmTL; and its asymptotic length was 70.5 cmTL. Its growth rate (K) was found 0.26 per year. The fishing mortality (F) of the species was found higher than its natural mortality (M), and its exploitation level (E) was 0.74, meaning that the species was already overfished. The exploitation should be reduced by 40–50% to keep the fish resources in Arafura sustainable, especially for areolate grouper. Keywords: fishing ground, bottom longline, exploitation level, tiger grouper, Arafura

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Some reproductive aspects of the areolate grouper, Epinephelus areolotus from the Gulf of Suez

Cited by 14 publications

References 10 publications

Population dynamics of reef fish in the Kwandang Bay, Sulawesi Sea, Indonesia

Population dynamics of reef fish in the Kwandang Bay, Sulawesi Sea, Indonesia

Age, growth and reproductive life‐history characteristics infer a high population productivity for the sustainably fished protogynous hermaphroditic yellowspotted rockcod (Epinephelus areolatus) in north‐western Australia

The Fishing Ground of Bottom Longline Vessels and Exploitation Rate of Tiger Grouper (<i>Epinephelus aerolatus</i>) in Arafura Waters

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