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1 Journal of Research in Biology An International Scientific Research Journal Original Research ISSN No: Print: ; Online: Length-Weight Relationships of 22 commercial fish from Margarita Island, Venezuela. Journal of Research in Biology Authors: Tagliafico A 1, Rago N 2 and Rangel MS 1. Institution: 1 Escuela de Ciencias Aplicadas del Mar, Universidad de Oriente, Boca de Río, Isla de Margarita, Venezuela. 2 Oceanografía y pesca, Fundación de Ciencias Naturales La Salle, Isla de Margarita, Venezuela. Corresponding author: Tagliafico A. ABSTRACT: Length-Weight Relaonships (LWR) were calculated for 22 commercial fish species caught by the arsanal fishing fleet of Margarita Island, Venezuela. A total of 1,610 specimens were analysed, distributed in the following species: Lagocephalus laevigatus, Sphyraena guachancho, S. barracuda, Lutjanus purpureus, L. analis, L. griseus, Rhomboplites aurorubens, Lachnolaimus maximus, Priacanthus arenatus, Scomberomorus cavalla, S. brasiliensis, Euthynnus alleeratus, Auxis thazard, Sarda sarda, Thunnus atlan!cus, Rachycentron canadum, Caranx hippos, C. crysos, Selene setapinnis, Alec!s ciliaris, Trachinotus carolinus and Elops saurus. These length-weight relaonships can be used to improve fish stascs because of difficulty in obtaining weight of the fish in field. Keywords: Lutjanidae, Scombridae, Carangidae, Elopidae, Sphyraenidae, Rachycentridae Arcle Citaon: Tagliafico A, Rago Nand Rangel MS. Length-Weight Relaonships of 22 commercial fish from Margarita Island, Venezuela. Journal of Research in Biology (2015) 5(3): Web Address: documents/ra0509.pdf Journal of Research in Biology An International Scientific Research Journal Dates: Received: 21 Jan 2015 Accepted: 08 Feb 2015 Published: 16 May 2015 This article is governed by the Creative Commons Attribution License ( licenses/by/4.0), which gives permission for unrestricted use, non-commercial, distribution and reproduction in all medium, provided the original work is properly cited JRB 2015 Vol 5 No 3

2 INTRODUCTION Estimation of biomass and regulation of catches are necessary for fishery management; but the direct measurement of the weight of each fish can be time consuming or impossible to obtain in field. For convenience, just size is often measured in body length, but the information about body weight is also taken into consideration. For this reason, Length-Weight Relationship (LWR) are useful tools and have been extensively used to estimate the weight from the length of the organisms (Sinovčić et al., 2004, Froese 2006, Froese et al., 2014, Xiong et al., 2014). However, LWR studies were only available for less than 12% (3,587 species) from around 32,470 species of fishes contained in FishBase (Froese et al., 2014), and even smaller if we only consider Caribbean or Venezuelan waters, where the information on the LWRs is mostly limited to a few species (Tagliafico et al., 2014). In this study LWRs were estimated for 22 commercial fish species of the region. MATERIALS AND METHODS The study was carried out in Margarita Island, Venezuela (10º51 50"-11º11'06"N/63º46 40"- 64º24'32"W), from January 2006 to December Fish landed at three fishing ports (Juan Griego, La Pared and El Tirano) and two fishing markets (Los Cocos and Conejeros) were sampled weekly. Specimens were caught using traps, beach seines: purse seine, single line, and gillnets and long-lines, latter being both surface and bottom. Detailed descriptions of vessels and fishing gears are provided by Iriarte (1997) and González et al., (2006). The specimens were identified using the keys of Cervigón (1991, 1993, 1994, 1996). Fish were weighed to the nearest 0.1 g and measured to the nearest 0.1 cm. Total length (TL) was used for Lagocephalus laevigatus (Linnaeus, 1766), Sphyraena guachancho (Cuvier, 1829), S. barracuda (Edwards, 1771), Lutjanus analis (Cuvier, 1828), L. griseus (Linnaeus, 1758), L. purpureus (Poey, 1866), Rhomboplites aurorubens (Cuvier, 1829), Lachnolaimus maximus (Walbaum, 1792), Priacanthus arenatus (Cuvier, 1829) and Rachycentron canadum (Linnaeus, 1766); whereas Fork Length (FL) was used for Scomberomorus cavalla (Cuvier, 1829), Scomberomorus brasiliensis (Collette et al., 1978), Euthynnus alletteratus Rafinesque 1810, Auxis thazard (Lacèpede, 1800), Thunnus atlanticus (Lesson, 1831), Sarda sarda (Bloch, 1793), Caranx hippos (Linnaeus, 1766), C. crysos (Mitchill, 1815), Selene setapinnis (Mitchill, 1815), Alectis ciliaris (Bloch, 1787), Trachinotus carolinus (Linnaeus, 1766) and Elops saurus (Linnaeus, 1766). The parameters a and b of LWR were estimated using the potential equation W=aLb; were W is the total weight expressed in grams, L the total or fork length according to the species expressed in centimetres, a is the intercept, and b is the slope (Beverton and Holt, 1957, Froese, 2006). The model fit to the data was measured by the coefficient of Pearson r-squared ( r 2 ) test and 95% confidence level of the limits of a and b were determined. RESULTS AND DISCUSSION A total of 1, 610 organisms belonging to 9 families and 22 species were analyzed (Fig. 1). Values of a and b, and their associated statistical information are provided in Table 1. The coefficients of correlation of the regressions ranged between 0.82 and 0.998, and all were highly significant (P<0.0001). The majority of the fish species studied show b- values within the standard range ( ) proposed by Froese (2006); only for Priacanthus arenatus (b=2.281), it was slightly lower than this range (Table 1). In Venezuela, for the fish studied, LWRs have only been previously reported for Lutjanus analis, L. griseus and Sphyraena guachancho. Similar b-values to previous studies were found for Lutjanidae, but for 1708 Journal of Research in Biology (2015) 5(3):

3 Table 1. Estimated length weight relationship parameters for 22 commercial fish species caught in an artisanal Caribbean Fishery *Fork length Species n L(cm) range W (g) range a 95% CI a b 95% CI b r 2 Tetraodontidae Lagocephalus laevigatus Sphyraenidae Sphyraena guachancho Sphyraena barracuda Lutjanidae Lutjanus purpureus Lutjanus analis Lutjanus griseus Rhomboplites aurorubens Labridae Lachnolaimus maximus Priacanthidae Priacanthus arenatus Scombridae Scomberomorus cavalla* S. brasiliensis* Euthynnus alletteratus* Auxis thazard* Sarda sarda* Thunnus atlanticus* Rachycentridae Rachycentron canadum Carangidae Caranx hippos* Selene setapinnis* Caranx crysos* Alectis ciliaris* Trachinotus carolinus* Elopidae Elops saurus* Journal of Research in Biology (2015) 5(3):

4 Tagliafico et al., 2015 Figure 1. Fish species analysed: a) Lagocephalus laevigatus, b) Sphyraena guachancho, c) S. barracuda, d) Lutjanus purpureus, e) L. analis, f) L. griseus, g) Rhomboplites aurorubens, h) Lachnolaimus maximus, i) Priacanthus arenatus, j) Scomberomorus cavalla, k) S. brasiliensis, l) Euthynnus alletteratus, m) Auxis thazard, n) Sarda sarda, o) Thunnus atlanticus, p) Rachycentron canadum, q) Caranx hippos, r) Caranx crysos, s) Selene setapinnis, t) Alectis ciliaris, u) Trachinotus carolinus and v) Elops saurus Journal of Research in Biology (2015) 5(3):

5 S. guachancho b-value was lower (n=251; b=2.704) than the previously registered in the area (n=45; b=3.271) (Etchevers, 1975). LWR in fish species could be affected by many factors, such as gonad maturity, sex, health, age, habitat, stomach full-ness, length ranges used, preservation methods, season, population, and environmental conditions (Tesch 1968, Pauly 1984, Froese 2006). Our study contributes to the expansion of knowledge on the Caribbean fish species. This area is globally acclaimed as a hotspot of endangered species (Cheung et al., 2007). The IUCN Red List catalogues the species Lutjanus analis and Lachnolaimus maximus as Vulnerable; other ten species are considered as Less Concern (Thunnus atlanticus, Scomberomorus cavalla, S. brasiliensis, Euthynnus alletteratus, Auxis thazard, Sarda sarda, Caranx hippos, C. crysos, Alectis ciliaris and Elops saurus), whereas the other 10 species analysed in this work have not been categorized. In this regard, Tagliafico et al., (2012) previously demonstrated that high frequency of all Lutjanidae species and Selene setapinnis, captured in Margarita Island, were inferior to the maturity length. Considering the information available in FishBase, this work provides the first data of LWRs for 18 commercial species from Venezuela (Froese and Pauly 2014) and represents an important baseline data for fisheries, making it useful for the management and conservation of these species. ACKNOWLEDGEMENTS The authors thank all the fisherman and sellers for the patience in the measurement of the specimens. To Asdrúbal Lárez and INIA for the logistic cooperation. REFERENCES Beverton JH, Holt SJ On the dynamics of exploited fish populations. Fish. Invest. Ser. II, Vol p. Cervigón F Los peces marinos de Venezuela. I. Fundación Científica Los Roques. ISBN , p. Cervigón F Los peces marinos de Venezuela. II. Fundación Museo del Mar. Caracas. 497 p. Cervigón F Los peces marinos de Venezuela. III. Fundación Museo del Mar. Caracas. 295 p. Cervigón F Los peces marinos de Venezuela. IV. Fundación Museo del Mar. Caracas. 254 p. Cheung WWL, Watson R, Morato T, Pitcher TJ, Pauly D Intrinsic vulnerability in the global fish catch. Mar Ecol Progr Series 333: 1-12 Etchevers S La relación longitud-peso en siete peces de interés comercial en el nororiente de Venezuela. Bol Inst Oceanogr 14(2): Froese R Cube law, condition factor and weight length relationships: history, meta-analysis and recommendations. J Appl Ichthyol 22(4): Froese R, Thorson JT, Reyes jr RB A Bayesian approach for estimating length-weight relationships in fishes. J Appl Ichthyol 30(1): Froese R, Pauly D, editors FishBase. World Wide Web electronic publication. Available at: (accessed on 10 December 2014). González LW, Eslava N, Guevara F Catálogo de la pesca artesanal del Estado Nueva Esparta, Venezuela. Instituto de Investigaciones Científicas, Universidad de Oriente, Boca de Río, Venezuela. ISBN p Iriarte L Embarcaciones, artes y métodos de pesca del estado Nueva Esparta. Fund. La Salle Cs. Nat. Monografía No. 42, Caracas. ISBN p. Journal of Research in Biology (2015) 5(3):

6 Pauly D Fish Population Dynamics in Tropical Waters: A Manual for Use with Programmable Calculators. ICLARM Studies and Reviews 8. ICLARM, Manila. 325 p. Sinovčić G, Franičević M, Zorica B, Čikeš-Keč V Length-weight and length-length relationships for 10 pelagic fish species from the Adriatic Sea (Croatia). J Appl Ichthyol 20(2): Tagliafico A, Rago N, Lárez A, Rangel S Estructura de talla de 20 especies de peces capturados por la flota artesanal de La Isla de Margarita, Venezuela. Ciencia 20(4): Tagliafico A, Rago N, Rangel MS Length- Weight Relationships of 21 species of Elasmobranchii from Margarita Island, Venezuela. J Res Biol 4 (7): Tesch FW Age and growth. In: Methods for assessment of fish production in fresh waters. W. E. Ricker (Ed.). Blackwell Scientific Publications, Oxford, pp Xiong W, Tao J, Zhang DC, Liu CL, He DK, Chen YF Length weight relationships for four small fish species caught in wetlands of central Yangtze River, China. J Appl Ichthyol 31: Submit your arcles online at Advantages Easy online submission Complete Peer review Affordable Charges Quick processing Extensive indexing You retain your copyright submit@jresearchbiology.com Journal of Research in Biology (2015) 5(3):