What determines the growth of tropical reef fish larvae in the plankton: food or temperature?

Abstract

The late-stage larvae of the reef fish Pomacentrus coelestis were collected using light traps at stations on a cross-shelf transect near Northwest Cape, Western Australia, during the spring and summer months (October to February) of 1997-98 and 1998-99. Physical (water temperature, wind) and biological (chlorophyll a, zooplankton abundance) variables were measured concurrently at each station. In 1997-98, environmental conditions were characterised by intrusive upwelling onto the shelf, relatively cooler water temperatures and higher chlorophyll a and zooplankton biomass. During the 1998-99 summer, water temperatures were warmer, and chlorophyll a and zooplankton biomass were relatively low. Catches of P. coelestis were much lower in the first summer (197 fish) than the second (1483 fish). Records of planktonic growth were obtained from otoliths of subsets of larvae from both summers. Growth varied among months within each summer; however, on average, larvae grew more slowly in the 1997-98 summer than the 1998-99 summer (0.48 mm d-1 vs 0.53 mm d-1 respectively), despite the presumed food (copepods) being more abundant in the plankton. Partial correlation analysis showed that water temperature explained approximately 30% of the variation in growth of larval P. coelestis. In contrast, chlorophyll a and zooplankton abundance explained much less (4.1 and 3.5%, respectively).

Environmental influences on larval duration, growth and magnitude of settlement of a coral reef fish

“…This result differs from studies in temperate and other tropical regions where water temperature is thought to be one of the primary determinants of growth rates (Campana and Hurley 1989;Suthers and Sundby 1993;Meekan et al 2003). In tropical NW Australia, Meekan et al (2003) found that water temperature explained 30% of the variation in growth rate of a larval pomacentrid. These contrasting results may be due to the relatively small temporal (seasonal, monthly and diurnal) ranges in temperatures that occur in Punta de San Blas (Table 1).…”

“…However, recent work has also shown that in tropical reef fishes larval condition and/or growth are important determinants of survivorship in the planktonic (Bergenius et al 2002;Wilson and Meekan 2002;Meekan et al 2003), as well as in the post-settlement stage (Searcy and Sponaugle 2001;Vigliola and Meekan 2002;McCormick and Hoey 2004).…”

“…These may act either directly or indirectly to influence growth rates. For example, water temperature may determine developmental time, growth, swimming performance (Meekan et al 2003;Green and Fisher 2004) and the rate of yolk sac absorption (Fukahara 1990) of young fish. Additionally, some species exhibit an optimal temperature range for development, outside of which mortality and abnormalities increase (Polo et al 1991).…”

Environmental factors influencing larval walleye pollock Theragra chalcogramma feeding in Alaskan waters

“…This is in agreement with other studies that have shown that shortly after hatching fish larvae dramatically improve their functional morphology, physiology and subsequent behavioral patterns resulting in advanced swimming performance and foraging success (Osse 1990, Porter & Theilacker 1999, Hunt von Herbing & Gallager 2000, Hunt von Herbing 2001. Similarly, increases in feeding were predicted under conditions of rising temperature, which has been shown to boost feeding rates in other studies on marine fish larvae (Houde 1989, Meekan et al 2003. The observed positive effect of temperature on feeding success might be the result of temperature affecting not only the larval physiology and therefore swimming performance but also the physics of the surrounding environment by decreasing its viscosity (Hunt von Herbing 2002).…”

Effects of climate change on fish reproduction and early life history stages

“…Higher metabolic rates mean that fish have higher basal energy demands at higher temperatures. Larval growth rates also increase with temperature for both temperate (Blaxter 1991;Benoît et al 2000) and tropical species (McCormick and Molony 1995;Meekan et al 2003;Green and Fisher 2004), with temperature explaining up to 89% of variation in growth rates among cohorts of some species (Sponaugle and Cowen 1996). Thermal reaction norms of growth in larval fish tend to be approximately linear until the lethal upper thermal limit is reached, at least in the majority of species studied to date (Sponaugle and Cowen 1996;Rombough 1997).…”