Lengthweight relationship and parameters of growth for the checkered puffer Sphoeroides testudineus from a karstic tropical coastal lagoon: La Carbonera, Yucatan, Mexico

Summary This study reports length-weight relationships and growth parameters for Sphoeorides testudineus from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. A total of 461 specimens were collected between April 2009 and March 2010. The lengthweight relationship was W = 0.061Lt 2.98 . Model parameters of the von Bertalanffy growth equation were: L ∞ = 29.50 cm, k = 0.77 year À1 and t 0 = À0.168 years. Introduction Sphoeroides testudineus, a member of the Tetraodontidae family, is known colloquially as checkered puffer and locally as 'xpu' (Mayan) and 'pez globo' (Spanish). It is an important estuarine-dependent fish species of ecological and commercial importance. The checkered puffer is the dominant species in many Yucatan coastal lagoons (Arceo-Carranza and Vega-Cendejas, 2009). The aim of this study was to present the LWR and to estimate the parameters of growth of S. testudineus from La Carbonera lagoon in northwestern Yucatan Peninsula. Materials and methods Samples of S. testudineus were collected during daytime between April 2009 and March 2010 in La Carbonera lagoon, a karstic coastal lagoon in northwestern Yucatan Peninsula, Mexico (21°13′-21°14′N; 89°52′-89°54′W). Collected specimens were euthanized in ice slurry, preserved in formaldehyde (4%) and transported to the laboratory where they were measured (±0.1 mm) and weighed (±0.01 g). The collected fishes were classified under three climatic seasons representing dry (March-June), rainy (July-October), and when there were prevailing north winds (NovemberFebruary). To determine parameters a and b, a regression analysis of log-converted total weight and total length was used. The 95% confidence intervals for b (CI 95%) were calculated to determine if the hypothetical value of isometry (3) fell between these intervals ÀkðtÀt0Þ , where Lt is the length at age t, L ∞ is asymptotic length, k is the growth rate (year À1 ) and t 0 is the hypothetical age of fish at length zero. The growth performance index (u') proposed by Results and discussion From a total of 461 of S. testudineus collected during the study period, 33.8% were collected in the dry season, 30.2% in the rainy season and 36% during the season when north winds prevaile