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

Abstract

The influence of environmental variables on the planktonic growth, pelagic larval duration and settlement magnitude was examined for the coral reef surgeonfish Acanthurus chirurgus. Newly settled fish were collected daily from patch reefs in the San Blas Archipelago, Caribbean Panama for 3.5 years. Environmental influences on growth were examined at three different life history stages: from 0 to 6 days, 7 to 25 days and from 26 to 50 days after hatching. Larval growth was correlated, using multiple regression techniques, with a combination of factors including solar radiation, rainfall, and along-shore winds. Depending on the life history stage, these accounted for 13-38% of the variation in growth rates when all the months were included in the analyses. Correlations between environmental variables and growth also varied among seasons and were stronger in the dry than in the wet season. During the dry season solar radiation, rainfall and along-shore winds described 57%, 86% and 74% of the variability in growth between 0 and 6 days, 7 and 25 days and 26 and 50 days, respectively. During the wet season rainfall, along-shore winds and temperature only described 38% of the variability in early growth and 27% of growth just before settlement. No significant model was found to describe growth 7-25 days after hatching during the wet season. Rainfall, solar radiation and along-shore winds were negatively correlated with growth up to 25 days after hatching but positively correlated as larvae approached settlement at a mean age of 52 days. Over 65% of the variability in pelagic larval duration was accounted for by a regression model that included solar radiation and along-shore winds. When data sets from wet and dry seasons were analysed separately, alongshore winds accounted for 67% of the change in larval duration in the dry season, and solar radiation accounted for 23% of the variation in larval duration in the wet season. Only 22% of the variability in settlement intensity could be described by solar radiation and temperature, when all months of the year were included in the analysis. Solar radiation and rainfall were included in a regression model that accounted for 40% of the variation in numbers of fish settling during the dry season. This study suggests that the levels of solar radiation, along-shore winds and rainfall during the early larval life can have important effects on the growth, larval duration and consequently, the settlement magnitude of marine fishes. Results also highlight the need to account for seasonality and ontogeny in studies of environmental influences.

Variable temporal relationships between environment and recruitment in coral reef fishes

“…Our finding that LEV appeared to be important in determining recruitment variability within and among taxa is consistent with the few other field studies that have examined LEV in the recruitment of coral reef fishes (Wilson & Meekan 2001, 2002, Bergenius et al 2005, Sponaugle et al 2006. The importance of LEV probably reflects their cumulative effect on growth and mortality rates throughout the larval stage.…”

“…Importantly, this suggests that the environmental variables that best predict recruitment can operate at different scales of temporal variation across taxa, which has implications for monitoring recruitment. For example, long-term studies with moderate to low sampling frequency may suffice to capture the bulk of variation in recruitment driven by the environment for Sparisoma spp., whereas a finer sampling resolution will be necessary for S. partitus.Our finding that LEV appeared to be important in determining recruitment variability within and among taxa is consistent with the few other field studies that have examined LEV in the recruitment of coral reef fishes (Wilson & Meekan 2001, 2002, Bergenius et al 2005, Sponaugle et al 2006. The importance of LEV probably reflects their cumulative effect on growth and mortality rates throughout the larval stage.…”

“…Solar radiation and rainfall, averaged over the larval duration, can also correlate with recruitment (e.g. Acanthurus chirurgus in Panama; Bergenius et al 2005). Nevertheless, the importance of different LEV and, in particular, the relative importance of LEV and SEV for coral reef fishes is poorly known because of the limited taxonomic and geographical scope of previous studies and because only 1 study (Wilson & Meekan 2001) has explicitly attempted to compare SEV and LEV.…”

Patterns and processes of larval fish supply to the coral reefs of the upper Florida Keys

“…Observed seasonal patterns of supply in these families could be the result of earlier peaks in spawning activity and/or differential survival or transport of eggs and larvae due to seasonal environmental shifts. Several recent studies have highlighted the importance of such shifts in wind, water temperature, and climate to the survival and growth of larvae as well as subsequent recruitment magnitude of reef fishes (Robertson et al 1999, Bergenius et al 2005, Sponaugle et al 2006). In the FK, a shift in the prevailing winds from weak SE winds in the summer to strong NE winds in the fall and winter reduces FC transport and shifts mean flows over the outer shelf and nearshore waters to become southwesterly in fall and winter months (Lee 1986).…”

Effect of rearing temperature on larval growth and the development in different tilapia species

“…Early ontogeny in fish is impacted by nearly all environmental factors, including temperature, oxygen content, salinity, pH, insolation, other biotic and anthropogenic factors (Jones, 2002;Kamler, 2002;, and even precipitation and winds that blow along coasts (Bergenius et al 2005). Among these factors, temperature is considered to be one of the more important, if not the most important, factors.…”