Reproduction and marine life history of an endemic amphidromous gobiid fish of Reunion Island

Abstract

Among amphidromous species, life-history traits of pelagic larvae show high variability between and within species and populations, due to the spatial and temporal variability of the marine environment. Temperature, food availability and seasonal conditions affect survival and larval growth. Among species with an extensive reproduction period, the pelagic conditions encountered by larvae vary according to the hatching date and induce variability in the postlarval and recruitment traits. Post-larvae of the amphidromous goby Cotylopus acutipinnis were collected every new moon between February 2008 and December 2009 at the mouth of a river on Reunion (Mascarene Archipelago, SW Indian Ocean). The relationship between pelagic larval duration (PLD), growth and marine temperature conditions was analysed using the chronological properties of otoliths. C. acutipinnis PLD (mean ± CI: 108.2 ± 1.2 d; range: 66 to 164 d) and size-atrecruitment (mean ± CI: 20.5 ± 0.1 mm; range: 17 to 23 mm) varied widely depending on the time of year. Back-calculation of hatching dates showed an extensive spawning season between November and July, which included 2 spawning peaks during the early austral summer and early winter. Summer spawning and high seawater temperature induced faster growth, shorter PLDs and smaller size-at-recruitment compared to early winter reproduction. The significant morphological changes that were demonstrated among amphidromous recruits might influence postrecruitment survival and juvenile settlement in freshwater. Selective mortality may occur according to early life-history traits such as growth patterns, size-at-recruitment and post-larval condition, and should be considered in population management.KEY WORDS: Cotylopus acutipinnis · Amphidromy · Otolith microstructure · Hatching date · Pelagic larval duration · Growth · Seasonal conditions · Sea surface temperature Resale or republication not permitted without written consent of the publisherAquat Biol 15: [225][226][227][228][229][230][231][232][233][234][235][236] 2012 The pelagic phase plays a fundamental role for amphidromous populations, as it allows larval dispersion and gene flow between fragmented freshwater settlement sites , Keith et al. 2005. Otolithometry (and, to a lesser extent, sclerochronology) is often used to characterise early life history traits of pelagic larvae (Sponaugle 2010). Among marine fishes, the influence of pelagic conditions on growth and size-at-recruitment has been demonstrated in both temperate (Raventos & Macpherson 2005, Fontes et al. 2011) and tropical waters (McCormick & Molony 1995, Searcy & Sponaugle 2000, Bergenius et al. 2005. Among amphidromous species, on the other hand, patterns of marine growth are less known (Shen & Tzeng 2008, Lord et al. 2010. Their pelagic larval duration (PLD) is longer than that of most marine demersal species (Brothers et al. 1983, Radtke et al. 2001, Hoareau et al. 2007, Lord et al. 2010, and a significant PLD and size-at-recruitment variability has been observed between and w...

Pelagic larval traits of the amphidromous gobySicyopterus lagocephalusdisplay seasonal variations related to temperature in La Réunion Island

“…The size-at-recruitment of S. lagocephalus (range from 26.5 to 37 mm TL) was consistent with that reported in previous studies in La R eunion (32.7 AE 1.1 mm TL; Hoareau et al 2007a) and in Pacific areas (26.17 AE 0.45 mm SL; Lord et al 2010). Radtke et al 2001;Maeda et al 2007;Teichert et al 2012) 2 0 -2 9 4 0 -4 9 6 0 -6 9 1 0 0 -1 0 9 8 0 -8 9 1 4 0 -1 4 9 1 2 0 -1 2 9 1 6 0 -1 6 9 1 8 0 -1 8 9 2 0 0 -2 0 9 2 2 0 -2 2 9 2 4 0 -2 4 9 2 6 0 -2 6 9 2 8 0 -2 8 9 6 As emphasised in other amphidromous (e.g.…”

“…It could be possible that larvae need to reach a minimum condition level or development stage before recruiting, which depends on the larval growth history in the sea (Searcy & Sponaugle 2000). It ranged from 4 to 5 lmÁday À1 at the beginning of the larval life to about 1 lmÁday À1 after 139 days, which is consistent with the findings of previous studies on S. lagocephalus (Lord et al 2010) and others amphidromous gobies (Lord et al 2010;Teichert et al 2012). However, our results showed that S. lagocephalus larvae recruited during the whole year with both PLD and size strongly related to the hatching date, showing that the seasonal effect was the main component of variability for these parameters.…”

“…Table 1. Radtke et al 2001;Maeda et al 2007;Shen & Tzeng 2008;Barbee et al 2011;Teichert et al 2012; this study), catadromous (e.g. The regression form is Y = b 0 + b 1 sin (R day ) + b 2 cos(R day ), where R day is the angular-transformed day of year and b 0 , b 1 , b 2 are the regressions coefficients.…”

“…Given an assumption of main local recruitment, it is expected that environmental conditions encountered by larvae, including seasonal fluctuations, are essential components to understand the patterns of early life history and their potential influence on dispersal ability. The postlarvae of S. lagocephalus recruited in river with a similar size to S. japonicus (range 30.7 to 38.1 mm TL; Shen & Tzeng 2008) but larger than most of others gobies, such as S. punctatum (range 16 to 25 mm SL; , Lentipes concolor (range 14.1 to 17.9 mm TL; Radtke et al 2001), Eleotris fusca (range 16 to 19 mm SL; Maeda et al 2007) or C. acutipinnis (range 17 to 23 mm TL; Hoareau et al 2007a;Teichert et al 2012). The postlarvae of S. lagocephalus recruited in river with a similar size to S. japonicus (range 30.7 to 38.1 mm TL; Shen & Tzeng 2008) but larger than most of others gobies, such as S. punctatum (range 16 to 25 mm SL; , Lentipes concolor (range 14.1 to 17.9 mm TL; Radtke et al 2001), Eleotris fusca (range 16 to 19 mm SL; Maeda et al 2007) or C. acutipinnis (range 17 to 23 mm TL; Hoareau et al 2007a;Teichert et al 2012).…”

“…oceanic currents, temperature, food availability, rainfall) greatly influence pelagic larval duration (PLD), size-at-recruitment and larval growth rate of many marine fish in temperate (e.g. Then others studies on amphidromous species showed that shorter PLDs and higher growth rates were generally observed during the warm season Radtke et al 2001;Maeda et al 2007;Teichert et al 2012) or high productivity periods (Shen & Tzeng 2008). McCormick & Molony 1995;Searcy & Sponaugle 2000;Bergenius et al 2005).…”