Family Belonidae from the Suez Canal, Egypt: Age, Growth, Mortality, Exploitation Rate and Reproductive Biology ⇑ Manal M

Egyptian Journal of Aquatic Research xxx (2017) xxx–xxx

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Egyptian Journal of Aquatic Research

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Full length article Family Belonidae from the Suez Canal, Egypt: Age, growth, mortality, exploitation rate and reproductive biology ⇑ Manal M. Sabrah , Amal M. Amin, Attia O. Attia

National Institute of Oceanography and Fisheries, B.O. Box 182, Suez, Egypt article info abstract

Article history: This is the first attempt to study the biological characteristics and basic population parameters of two Received 13 October 2017 important Belonidae species, Tylosurus acus and Tylosurus crocodilus from the Suez Canal. The length– Revised 13 December 2017 weight relationship was estimated as W = 0.0005TL3.26 for T. acus and W = 0.0007TL3.21 for T. crocodilus. Accepted 14 December 2017 The growth parameters of T. acus were computed as L1 = 79.85 cm, k = 0.44 year–1, t = –0.58 years, Available online xxxx 0 while the annual total, natural and fishing mortality were 1.70, 0.72 and 0.98 respectively with an exploitation rate of 0.58. While in T. crocodilus the VBGPs were L1 = 113.0 cm, k = 0.30 year–1, Keywords: t = –0.46 years, the annual total, natural and fishing mortality were 1.27, 0.51 and 0.76 respectively with Tylosurus acus 0 an exploitation rate of 0.60. The female’s length at first maturity of T. acus was estimated to be 47.3 cm Tylosurus crocodilus Population dynamics and 51.7 cm for T. crocodilus. Monthly variations in Gonado-somatic index revealed that the spawning Length at maturity season of the two species takes place in spring. Results of exploitation rate indicated that the T. acus Spawning period and T. crocodilus are fully exploited. Published by Elsevier B.V. on behalf of National Institute of Oceanography and Fisheries. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction Several studies have been done on the distribution of Tylosurus species along the Mediterranean Sea (Bello 1995; Akyol and Kara, Family Belonidae consists of 10 genera and about 32 species, 2011; Türker Çakır and Zengin, 2013; Imsiridou et al., 2014).), only 8 species belonging to 4 genera are in the Western Indian but information on its biological traits remains rare. The reproduc- Ocean. The genus Tylosurus is the most abundantly present one tive biology of Tylosurus genera is rather limited to T. acus melan- in the Suez Canal represented by three species, Tylosurus acus impe- otus in the waters of southeastern Taiwan (Liao and Chang, rialis, Tylosurus crocodilus crocodilus and Tylosurus choram, while 2011). Moreover Trindade-Santos and Freire (2015) had performed the genus Ablennes is represented by the flat needlefish Ablennes an analysis on the reproductive patterns of T. crocodiles in Brazil. hians. The weight-length relationships of T. acus imperialis were studied Belonidae species are Red Sea endemic species (Parin, 1967; for the first time in the fish population of the North Aegean Sea Froese and Pauly, 2015), constituting of about 3% of the total Red (Minos and Kokokiris, 2015). Despite Tylosurus crocodilus being a Sea production (GAFRD, 2014). Nowadays, Belonidae has appeared pelagic species, which is distributed from South Africa through and distributed along the Mediterranean Sea via the Suez Canal as the Red Sea to India, there are few studies that deal with its biolog- an invasive species (Sinis, 2005, Fricke et al., 2011; Galil et al., ical parameters (Letourneur et al., 1998; Kulbicki et al., 2005). 2011). The present study is considered to be the first investigation of The needlefish, T. crocodilus and T. acus are marine pelagic fish. the essential biological and dynamical parameters for two They live in solitary or in small groups (Collette, 1999) and are Tylosurus species in the Egyptian coastal waters. This data will be widely distributed in tropical and subtropical waters. They inhibit considering an important background reveal the fishery status of offshore waters and can also be found in coastal waters (Collette, the needlefish. 2003; and Froese and Pauly, 2014). They are found in a depth range of 1–10 m (Fricke et al., 2011). Material and methods

Study area Peer review under responsibility of National Institute of Oceanography and Fisheries. ⇑ Corresponding author. The Suez Canal can be considered a capillary tube that connects E-mail address: [email protected] (M.M. Sabrah). two large basins, the Mediterranean and the Red Seas (Fig. 1). It lies https://doi.org/10.1016/j.ejar.2017.12.003 1687-4285/Published by Elsevier B.V. on behalf of National Institute of Oceanography and Fisheries. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Please cite this article in press as: Sabrah, M.M., et al. Family Belonidae from the Suez Canal, Egypt: Age, growth, mortality, exploitation rate and reproductive biology. Egyptian Journal of Aquatic Research (2017), https://doi.org/10.1016/j.ejar.2017.12.003 2 M.M. Sabrah et al. / Egyptian Journal of Aquatic Research xxx (2017) xxx–xxx

Fig. 2. Belonidae samples from Bitter lakes at the Suez Canal.

Methods

Age determination was carried out by otolith reading. The otolith was extracted and kept in a special envelop for future reading. The whole otolith was examined under a stereo microscope at a magniﬁcation of 40 X and viewed with reﬂected light against a black background. The length-weight relationship was determined for the two species, using the equation of Le Cren, (1951) W=aLb, where W is the total weight in grams, L is the total length in cm and the parameters (a) and (b) are constants. The growth parameters of the von Bertalanffy growth model K, L1 were estimated by the method of Ford (1933) -Walford (1946). The empirical equa- Fig. 1. Map demonstrates landing site at the Great Bitter Lakes. tion of Pauly, 1979 was used to estimate the hypothetical age

(to): to = t + (1/K) ⁄ ln ((L1- Lt)/L1). The von Bertalanffy, 1938 Growth Formula (VBGF) was used in order to determine the rela-

0 0 0 0 tionship between length and age, using the following equation between 29° 55 &31° 25 latitude north and 32° 15 &32° 35 lon- k(t-t0) for growth in length: Lt =L1 [1 - e- ], where, Lt = mean length gitude east. The Canal extends approximately 193.30 km long, 24 at age t, L1 = asymptotic length and K = growth coefficient, deter- m deep and 205 m wide. The rest of the Canal extends through a mining the rate of change in the length increment, t = age group of series of lakes with different ecological conditions, from north to the studying species and t0 = the hypothetical age at which the south: Lake Manzala, Lake Timsah, and the Great and Little Bitter length is zero. The von Bertalanffy growth in weight equation is: Lakes. k(t-t0) b Wt=W1 [1 - e- ] , where Wt is the weight at age t, W1 is the asymptotic weight and b is the length weight relationship con- stant. The growth performance index was estimated by (Pauly and Materials Munro, 1984) equation. Ø = Log K + 2 Log L1. By applying of FiSAT software program (Gayanilo et al., 1997), the instantaneous rate of Random samples of Family Belonidae were collected monthly total mortality (Z) was estimated using the catch curve method from the artisanal boats using gill and trammel nets along the Suez described by (Pauly, 1983). The instantaneous rate of natural mor- Canal and landed their production in the Great Bitter Lakes fishing tality (M) was computed using Pauly’s (1980) empirical equation port (Fig. 1) during the fishing period from Sep. 2013 to Aug. 2014. with mean annual water temperature of 22.5 °C(Hamed et al., 809 specimens (Fig. 2) were collected; samples were identified into 2012). The instantaneous rate of fishing mortality (F) was extracted four species; 250 specimens were T. crocodiles, 210 specimens were as: F = Z-M and the exploitation rate was calculated as E = F/Z. The

T. acus, 180 specimens were T. choram and 169 specimens were length at first capture Lc was estimated by Pauly (1984b,c). The Albeno hains. Fish species were identified and checked according length at first sexual maturity (Lm) was computed by fitting the to FAO species identification sheets fishing Area 51, (W. Indian maturity percentage against the length range of 5 cm intervals.

Ocean), 1984 (Belonidae) (Fischer and Bianchi, 1984). (Lm) was determined by having the point on X-axis corresponding Two species, T. acus, and T. crocodilus crocodile were selected for to 50% on Y-axis according to Pitt (1970). The spawning season was a study of their biological and dynamical characteristics, as they obtained by estimating the monthly average Gonado-somatic are the most common and commercial species. All specimens were index (GSI) for both male and female as a percentage of the gonad measured to the nearest 0.1 cm total length and weighed to the weight to the total body weight of the ﬁsh as the following equa- nearest 0.1 gm. tion: GSI = G.Wt/T.Wt 100 (King, 1995).