Spawning seasons, spawning grounds and nursery ...

The Global Journal of Fisheries and Aqua. Res. - Vol. 6 No. 6, (2013) - ISSN 18191

Spawning seasons, spawning grounds and nursery grounds of some Red Sea fishes Mohamed Abu El-Regal Marine Science Department, Faculty of Science, Port Said University

ABSTRACT

T

his study is an attempt to utilize the larval and juvenile stages of some Red Sea fishes life to determine their spawning seasons, spawning grounds and nursery grounds of some reef fishes in the Red Sea. Fish larvae were collected from different areas along the Red Sea coast by plankton net. The larvae were classified to yolk sac, preflexion and postflexion larvae stages and the abundance and distribution of each stage was determined. Juvenile fishes were collected from mangroves and sandy shores using beach seine and counted visually on seagrass beds and coral reefs in order to determine the nursery areas. A total of 2453 larvae representing 93 reef fish taxa were collected and the time of occurrence of each taxon was used as indication of the spawning seasons. Thirty one species constituting 33% of all studied species were found to be of commercial importance. These species were followed to detect when and where they spawn and where they settle down. Commercial fishes were classified into 5 categories according to their spawning season. Most of the fishes spawn in the warmer months of the year (May to August). Most reef fishes spawn away from the reef and only few species spawn close to the reef and settle on it or either on mangroves or sea grasses.

Key words: Red Sea, fish larvae, spawning seasons, spawning grounds

Proc. of The 6th Global Fisheries & Aqua. Research Conf., Egypt, (2013) pp. 105- 125

Spawning seasons, spawning grounds and nursery grounds of some Red Sea fishes

INTRODUCTION Fisheries management in the Red Sea depends mainly on the traditional approach that focuses on the management of a single species. However, very few species have been studied. The high fish diversity of the Red Sea (more than 1000 species) makes it very difficult, costly and time consuming to depend on such traditional tools. As many species in the Red Sea are now exploited or even overfished, actions should be taken to protect the spawning stocks of these species. For these actions to be effective they should be built upon a solid scientific base that uses a different approach. New approach of management, flexible enough to respond to the evolution of the fishery resources, is necessary to ensure stable and sustainable long-term exploitation (Miller and Kendall, 2009). The new technique should help managers to have data about many species at very short time. This could be easily achieved by studying the early stages of fishes that include eggs and larvae which allow quantitative sampling of several species over broad areas in short time with simple plankton net handled by different types of vessels without major installation of equipments (Smith and Richardson, 1977). The Fish eggs and larvae have played an important role in fishery management and promise to contribute significantly to supplementation and conservation of fish stocks in the future. There has been explosive growth in research on early life of fishes over the past 40 years (Rutherford, 2002; Pattira et al., 2012). It is now clear that information derived from the fish eggs and larvae makes a number of unique contributions to fishery sciences that are crucial for accurate assessment and management of fish populations (Fuiman and Werner, 2002). Despite the great contribution of early stages of fishes in the fisheries management, few studies have been conducted. The aim of this study is to use the early stages of fish; larvae and juvenile stages in order to determine the spawning seasons, spawning grounds and nursery areas of some reef fishes in the Red Sea. Few studies have been conducted on the larvae of the Egyptian Red Sea (Abu El-Regal, 1999; Abu El-Regal et al, 2008; Abu El-Regal, 2009; Abu El-Regal, 2013).

MATERIALS AND METHODS Fish larvae were collected from different areas along the Egyptian Red Sea coast throughout a period of a year from January to December 2011. Larvae were collected from some sites in Hurghada, Safaga, Qussier, Marsa Alam and Shalateen ( Fig.1) by plankton nets of 100 cm mouth diameter plankton net with a mesh size of 0.5 mm. Net was towed horizontally parallel to the reef and about 10-50 m away from the reef edge for 10 minutes with a towing speed of 1.5 knots. Samples were taken in the early morning just before sunrise and preserved in buffered 5% formalin solution in seawater on board. Larvae were sorted, measured and identified to the nearest taxa. All larvae were measured to 0.1 mm. The identified larvae were divided into yolk sac larvae, preflexion and postflexion larvae. Yolk sac larvae are those have the remaining of the yolk and the preflexion larvae are those with inflexed notochord that 127

Mohamed Abu El-Regal is parallel to the body axis whereas, the postflexion larvae are larvae that have the notochord flexed and vertical to the body axis. Abundance of larvae was expressed as number of larvae at 1000 m3 of filtered water. Juvenile fishes of the commercial species whose larvae were collected during this work were followed to detect where they are settled. They were collected from mangrove in Qussier, Wadi Qula’an and Hamata in the southern Egyptian Red Sea by small beach seine and sandy area in Hurghada and were visually counted in different seagrasses and coral reef areas in order to find out what species have their juvenile stages (Table 1).

Table (1) Sites, type of habitat, the sampled stage and the coordinates of each site Name Hurghada Safaga Qussier Marsa Alam Qul’an Hamata Shalateen

Habitat

Sampled stage

Coral reefs Sandy areas Coral reefs Mangrove Seagrasses Coral reefs Mangrove Mangroves Coral reefs

Fish larvae Juvenile Fish larvae Juvenile Juvenile Fish larvae Juvenile Juvenile Fish larvae

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Position 27° 13ˋ 50 N 0.33° 50ˋ 36 E 26° 54ˋ 00 N 33° 57ˋ 46 E 25° 52ˋ 06 N 34° 24ˋ 48 E 25° 20ˋ 28 N 34° 44ˋ 17 E 24° 21ˋ 33 N 35° 17ˋ 46 E 24° 21ˋ 33 N 35° 17ˋ 46 E‫ــ‬ 23° 9ˋ 34 N 35° 36ˋ 48 E


Fig. (1) Red Sea map showing sites of study

RESULTS AND DISCUSSION Larvae of 93 fish taxa were collected and their time of occurrence was used as indication of their spawning seasons. Most reef fishes spawn in the warmer months of the year (May to August) based on the occurrence of their larvae (Fig.2). According to their spawning seasons, fishes could be categorized into 8 groups (Fig.3). These were the autumn spawners, the winter, the spring, the spring /summer, the summer, the summer/autumn, autumn/winter spawners and the prolonged spawning season groups (Table 2) The highest number of spawners comes under the summer spawners group with 36 taxa involved forming about 39% of all taxa. Whereas, the autumn and 129

Mohamed Abu El-Regal autumn/winter spawners included the lowest number of taxa with only one taxon recorded.

Fig.(2) The number of taxa of fish larvae in different months

Fig.(3) Number of species in the different spawning seasons

Fig.(4) Percentage of spawning season for different commercial taxa.

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Table (2) Spawning seasons of the collected fish larvae during the current study

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Mohamed Abu El-Regal Of the 93 collected species, 31 species forming about 33% of all species were belonging to commercial species. These species could be categorized into 5 groups; spring, summer, winter, spring/summer and prolonged. Most of the commercial species spawn in the warmer months of the year from May to August. They formed 61% of all commercial species. The 13 summer spawners formed 44% of the commercial species. Winter and spring attained 6 species and 5 species forming 19% and 16% of the commercial species, respectively (Fig.4). Two species were found to spawn at different seasons without a regular pattern of spawning. These species belong to families Clupeidae and Engraulidae.

Table (3) Spawning seasons, grounds, nursery grounds and abundance of fish larvae of the commercial species collected during the present work

Spring spawners Acanthopagrus bifasciatus, Trachurus indicus, Trachinotus sp. (possibly T. baillonii or T. blochii), ??? Caranx sp., and Rhabdosargus sp. 132

Spawning seasons, spawning grounds and nursery grounds of some Red Sea fishes Spring/Summer spawners Hyporhamphus gamberur, Platybelone argalus, Tylosurus choram, Gerres oyena, , Siganus sp., and Mugilidae Summer spawners Myripristis murdjan, Mulloidichthys flavolineatus, Paracaesio sordidus, Priacanthus hamrur, Synodus variegates, Sphyraena sp. Sargocentron sp., Caranx sp1., Lutjanus sp, Epinephelus sp., Scaridae, Soleidae, and Bothidae. Winter spawners Scomber japonicus, Trichiurus auriga, Bothidae, Haemulidae, and Saurida sp.,. Prolonged spawning season Spratelloides delicatulus, and Engraulidae. Spawning grounds Determination of spawning and nursery grounds depends mainly on the stage of larvae that were collected and where it was collected. The utilization of the earliest stages of eggs and yolk-sac larvae is a good indicator of the spawning and nursery grounds. The measurements of the larval size indicates that Gerres oyena spawn close to the coast near the reef. Most of the studied species seem to spawn in the open water where 16 species forming 51% of the species were recorded. On the other hand 7 species forming 22% of the commercial species were found to spawn in the lagoons (Fig. 5). Mulloides flavolineatus performs an annual migration to the sandy shores in May, June, July and August but no evidences of spawning were found. All the small and preflexion larvae of this species were collected either from the open water or very exposed reef areas indicting that these larvae may be brought to the reef by the strong currents. Spartelloides delicatulus seems to spawn in the coastal and reef lagoons as larvae of different size classes were collected from these lagoons in very large numbers. Spawning grounds used by reef fishes could be categorized into three categories; reef, lagoon and open water (Table 3).

Fig. (5) Number of species in each spawning area

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Mohamed Abu El-Regal Nursery grounds Fishes were found to have different nursery areas according to the settlement place. Mangroves, seagrasses, coral reefs, and sandy shores. Some species were found to occur in more than one habitat. Juveniles of Platbelone argalus were found to occur both in coral reefs and seagrasses. Coral reefs were found to be the most frequently used as nursery area where 12 species forming 38% of the studied species used coral reefs for settlement. Mangroves were the second most frequently used ecosystem where 10 species forming 32% of the species used mangroves for settlement (Fig. 6). Seagrasses and sandy shores had almost the same importance for the studied species with 2 species forming 6% of all recorded species. Areas where larvae of some species are settled could not be precisely detected during this study and were referred as unknown in the figure.

Fig. (6) Number of species in each nursery area

Gerres oyena Although the gerreid larvae were only taken from two months; May and June (Fig.7), they were the fourth most abundant taxa in the collection after Mulloides flavolineatus and Spratelloides delicatulus accounting for 3.7% of all collected larvae with a total abundance of 90 larvae/1000m3 (Table 3). They were restricted to the inshore sites. Size of the larvae of Gerres oyena ranged from 2.2 mm to 8.8 mm. All the larvae were taken from a coastal reef lagoon. Most of larvae were small and preflexion (Fig.8).

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Fig. (7) Monthly variation in abundance of larvae of G. oyena collected during the survey

Fig. (8) Length frequency distribution of larvae of G. oyena

Mulloides flavolineatus Larvae of this species was first most abundant of all species constituting approximately 73% of all collected larvae with a total abundance of 1809 individuals/1000 m3 (Table 3). These larvae were restricted to the warmer months of the year (June-August) (Fig.9). Most of collected larvae were small and preflexion and few larvae were large postflexion. The size ranged from 2 mm to 10 mm. most of the small preflexion larvae were taken from the exposed sides of the coral reefs whereas, all the larger postflexion larvae were found in sheltered sides of the reef. Juvenile of M. flavolineatus were collected from sandy shores by beach seine in January.

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Mohamed Abu El-Regal

Fig. (9) Monthly variation in abundance of larvae of M. flavolineatus

Fig. (10) Length frequency distribution of goatfish larvae in June, July and flavolineatus

136

August of M.

Spawning seasons, spawning grounds and nursery grounds of some Red Sea fishes Siganus rivulatus The larvae of rabbitfishes formed about 1% of the total larvae and an average density of 25/1000 m3. They occurred only in May. Siganid larvae were collected from all sites but were most common in sheltered inshore sites. All siganid larvae were in the preflexion stage with the size ranging from 2.5 to 4.5 mm. The majority of siganid larvae were small and preflexion ranging in size from 1.8 mm to 4mm. All were taken from a sheltered lagoon. Only one larva of 5 mm was taken from the open water. In several cases the spawning seasons of these taxa as determined from the present work based on the seasonal occurrence of larvae coincides to a large extent with that obtained from the literature based on the reproductive biological studies. Determination of spawning seasons by larval fishes coincides with that determined by the reproductive biology. Mulloidichthys flavolineatus has peak of spawning from June to August as indicated by the gonado-somatic index analysis and abundance of fish larvae. Data about the spawning season of M. flavolineatus is in agreement with the very few reports about the species either globally (Munro et al., 1973; Houde et al., 1986) or locally in the Red Sea (Boraey, 1969). In the Arabian Gulf, mullid larvae were abundant from late spring to autumn and were absent in winter (Houde et al., 1986). In the Caribbean Sea, ripe females were caught in March and April (Munro et al., 1973). This study presents important information on the spawning seasons and grounds of reef fishes in the area that form baseline data concerning the seasons and areas of spawning of commercial fishes. It reflects the importance of the eggs and larvae survey in fisheries management. However, the larvae of some fishes whose adults are important constituents of Egyptian fisheries were rare or even missing in the collection. This may be due to the behaviour of the adult or the behaviour of the larvae (Leis, 1991b; Montgomery et al., 2001). Larvae of lethrinid fishes were absent in the ichthyoplankton samples during the present study and previous studies in the Egyptian Red Sea (Abu El-Regal, 1999, 2008, 2009). Lethrinid larvae were found to preferentially settle near the seagrass-replete reef (Olney and Boehlert, 1988). These findings may confirm that these fishes migrate to areas more favorable for their spawning (Johannes, 1978). The absence of these larvae could be also attributed to the sampling methods that are used during the current study which depends mainly on the surface sampling. Most reef fishes in the Red sea are of commercial importance and should be protected by law.

CONCLUSION This study includes very valuable data about the spawning seasons of the reef fishes in the Red Sea and can be used for the management of their fisheries. It forms a baseline to build upon when making any decision about the management and conservation of the red sea reef fishes.

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Mohamed Abu El-Regal

REFERENCES Abu El-Regal, M. A. and T. Kon (2008). First record of paedomorphic fish Schindleria (Gobioidei-Schnidleriidae) from the Red Sea. Journal of Fish Biology. (72): 1539-1543. Abu El-Regal, M. A. (1999). Some biological and ecological studies on the larvae of coral reef fishes in Sharm El-Sheikh (Gulf of Aqaba-Red Sea). M.Sc. Thesis. Marine Science Department, Faculty of Science Suez Canal University. 167 pp. Abu El-Regal, M. A. (2012). Larval development of two atherinid fish species from the Red Sea, Egypt. Egyptian Journal of Aquatic Biology and Fisheries. 16(1): 61-71 Abu El-Regal, M. A. (2009). Spatial distribution of larval fish assemblages in some coastal bays along the Egyptian Red Sea coast. J. Egypt. Acad. Soc. Environ. Develop., (10): 19-31 Abu El-Regal, M. A.; A. E. Ahmed; S. G., El-Etreby; M. El-Komi and M. Elliott (2008). Influence of exposure and distance offshore on the spatial distribution of larval fish assemblages. The 32nd Annual Larval Fish Conference, Kiel, Germany, 3-7 August, 2008 Abu El-Regal, M. A.; A. E. Ahmed; S. G., El-Etreby; M. El-Komi and M.Elliott (2008). Abundance and diversity of coral reef fish larvae at Hurghada, Egyptian Red Sea. Egyptian Journal of Aquatic Biology and Fisheries. 12(2). 17-33 Abu El-Regal, M. A.; A. E. Ahmed; S. G., El-Etreby; M. El-Komi and M., Elliott (2008). Influence of ecological guilds of coral reef fishes on the distribution of their larval near coral reefs at Hurghada, Egyptian Red Sea. Egyptian Journal of Aquatic Biology and Fisheries. (12): 35-50 Abu El-Regal, M.A. 2013. Adult and larval reef fish communities in coastal reef lagoon at Hurghada, Red Sea, Egypt. International Journal of Environmental Science And Engineering, (4):39-49 Ahmed, A. E (1992). Ecological and Biological studies on juvenile fishes in South Sinai. M.Sc. Thesis. Marine Science Department, Faculty of Science, Suez Canal University. Egypt. 120 pp. Al-Kholy, A. (1964). Red Sea Fisheries. General Egyptian Organization of Aquatic Resources. Cairo. 345 pp. Anderson, P. J. and Piatt, J. F. (1999). Community reorganization in the Gulf of Alaska following ocean climate regime shift. Mar. Ecol. Prog. Ser., (189):117123 Armstrong, M. J.; P., Connolly; R. D. M. Nash; M., Pawson; E. Alesworth; P. J. Coulahan; P. R. Withames; and L. Woolner, (2001). An application of the annual egg production method to estimate the spawning biomass of cod (Gadus morhua L.), plaice (Pleuronctes platessa L.) and sole (Solea solea L.) in the Irish Sea. ICES J. Mar. Sci., (58):183-203. 138

Spawning seasons, spawning grounds and nursery grounds of some Red Sea fishes Brogan, M. W. (1994a). Distribution and retention of larval fishes near the reefs in the Gulf of California. Mar. Ecol. Prog. Ser., (115):1-13 Brogan, M. W. (1994b). Two methods of sampling fish larvae over reefs: A comparison from the Gulf of California. Mar. Biol., (118):33-44 Fuiman, L. and A. Werner. (2002). Special considerations of fish eggs and larvae. In: Fuiman, L.A., Werner, R.G. (Eds.), Fishery Science. The Unique Contributions of Early Life Stages. Fishery Blackwell Publishing. pp.206-221. Houde, E. D.; S. Almatar; J. C. Leak and C. E. Dowd. (1986). Ichthyoplankton abundance and diversity in the Western Arabian Gulf. Kuwait Bul. Mar. Sci., (8):107-393. Johannes, R. E. (1978). Reproduction strategies of coastal marine fishes in the tropics. Environ. Biol. Fish., (3), 141-160. Leis, J. M. (1991a). The pelagic stage of reef fishes: The larval biology of coral reefs. In: Sale, P. F. the ecology of fishes on coral reefs. Academic Press,. pp 183230 Leis, J. M. (1991b). Vertical distribution of fish larvae in the Great Barrier Reef lagoon, Australia. Mar. Biol., (109): 157-166. Leis, J.M. and and B. M. Carson-Ewart. (2002). Larvae of Indo-Pacific coastal fishes. An identification guide to marine fish larvae. (Fauna Malesiana Handbooks 2). E. J. Brill, Leiden, 850 pp. Miller, S. M.; A. W. Kendall. (2009). Early life history of marine fishes. University of California Press Miller, M. J.; J. Aoyama; N. Mochioka; T. Otake; P. H. J. Castle; G. Minagawa; T. Inagaki and K. Tsukamoto (2006). Geographical variation in the assemblages of leptocephali in the western South pacific. Deep Sea Res., (1): 776-794 Montgomery, J.C.; T. Nicholas and O. S. and Haine (2001). Active habitat selection by presettlement reef fishes. Fish and Fisheries., ( 2): 261-277. Munro, J. L.; R. Thompson and V. C. Gaut (1973). The spawning seasons of Caribbean reef fishes. J. Fish. Biol., (5):69-84. Pattira L.; N. Chirat; P. Paitoon; R. Jalilur: U. H. Aung; and U. W. Aung (2012). Composition, Abundance and Distribution of Fish Larvae in the Bay of Bengal. The Ecosystem-Based Fishery Management in the Bay of Bengal Rutherford, E. S. (2002). Fishery management. In: Fuiman, L.A., Werner, R.G. (Eds.), Fishery Science. The Unique Contributions of Early Life Stages. Fishery Blackwell Publishing. pp.206-221. Smith, P. E. and S. L. Richardson (1977). Standard techniques of pelagic eggs and larvae surveys. FAO Fish. Tech. Pap. (175):1-100.

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‫مواسم التبويض ومناطق التبويض ومناطق التحضين لبعض أسماك البحر‬ ‫األحمر‬ ‫محمد أحمد أبو الرجال‬ ‫قسٌ ػيى ً اىثحاس ‪ ،‬مييح اىؼيىً ‪ ،‬جاٍؼح تىسسؼيذ‬ ‫ذهذف هزٓ اىذساسح إىً اسرخذاً اىَشاحو اىَثنشج ٍِ حياج األسَاك فً ذحذيذ ٍىاسٌ وٍْاطق‬ ‫اىرثىيض ومزىل ٍْاطق ذحضيِ تؼض األسَاك االقرصاديح تاىثحش األحَش‪ .‬ذٌ ذجَيغ يشقاخ األسَاك‬ ‫‪2011‬‬ ‫ٍِ ػذج ٍْاطق تاىغشدقح وشفاجا واىقصيش وٍشسً ػيٌ وشالذيِ ػيً ٍذي ػاً ماٍو هى‬ ‫تاسرخذاً شثاك تالّنرىُ فرحاذها ‪ .ٌٍ 0.5‬ذٌ ذقسيٌ اىيشقاخ اىرً ذٌ جَؼها حسة دسجح اىَْى إىً ثالثح‬ ‫ٍجَىػاخ وذٌ حساب مثافح مو ٍجَىػح ىرحذيذ ٍْاطق اىرثىيض واىرحضيِ‪ .‬ذٌ جَغ صغاس األسَاك‬ ‫ٍِ ٍْاطق اىَاّجشوف تيقصيش وحَاطح وقيؼاُ تاسرخذاً جشافح ساحييح مَا ذٌ ذسجيو صغاس األسَاك‬ ‫تَْاطق اىحشائش ىثحشيح واىشؼاب اىَشجاّيح ػِ طشيق اىؼذ ذحد اىَاء تاسرخذاً ٍؼذاخ غىص‪ .‬ذٌ‬ ‫ذسجيو ‪ّ 93‬ىع ٍِ االسَاك خاله فرشج اىذساسح ذٌ فصو ‪ّ 31‬ىع ٍْها راخ أهَيً اقرصاديح ىررثغ‬ ‫وذحذيذ ٍىاسٌ وٍْاطق اىرثىيض ومزىل ٍْاطق اىرحضيِ‪ .‬وجذ أُ ٍؼظٌ األّىاع االقرصاديح ذرناثش فً‬ ‫فصو اىصيف‪ .‬تاىْسثح ىَْاطق اىرثىيض وجذ أُ حىاىً ‪ ٍِ %50‬األّىاع ذرناثش فً اىَيآ اىَفرىحح‪.‬‬ ‫مَا وجذ أُ ٍْاطق اىشؼاب اىَشجاّيح وٍْاطق اىَاّجشوف هً أمثش اىَْاطق اىرً ذسخذٍها األّىاع‬ ‫ذحد اىذساسح مَْاطق ذحضيِ‪.‬‬ ‫ذثشص هزٓ اىذساسح أهَيح اسرخذاً اىَشاحو اىَثنشج ٍِ حياج األسَاك فً ذْظيٌ اىَصايح‬ ‫وحَايح اسَاك اىشؼاب اىَشجاّيح‪.‬‬

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