Vital rates of sardine and anchovy larvae: trying to shed new light on early life history dynamics

36th Annual Larval Fish Conference, 2-6 July 2012, Os, NorwayLaboratory experiments to study the vital rates of sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) larvae in relation to differences in several key physical and biological factors considered most important for regulating their growth and survival, are being carried out in the framework of the project VITAL, financed by the Portuguese Foundation for Science and Technology (PTDC/MAR/111304/2009). The experiments aim at obtaining parameters such as the physiological tolerance limits of temperature, salinity and food availability for larvae survival and their influence on larval growth and ingestion rates. The nutritional condition of larvae reared in the laboratory is being monitored and compared with larvae collected in the wild, validating combined techniques (fatty acids and RNA/DNA). The quantitative estimates of the vital rates for the larvae of these fish species under controlled laboratory conditions will be used for parameterize an individual-based model to couple to a hydrodynamic model developed for the western Portuguese coast. Efforts to build models describing environmental regulation of small pelagic fish species (e.g., to examine links between climate and recruitment) are currently hampered by a lack of data such as the vital rates of the larval phase, to which we hope to contribute with our research. In this talk, we will present a synopsis of the results obtained so far for sardines, from adult fish collection and spawning initiation to the experiments of growth rates of sardine larvae under different prey regimes. Nearly 300 adult sardines were acclimated to a tank of the Oceanrio de Lisboa and since 2010 have spawned viable eggs for more than 200 days. Although there were no significant differences in egg size, the mean size of sardine larvae at hatch was significantly different amongst experiments (2.8 - 4.8 mm). Interestingly, in those experiments which had, on average, smaller larvae at hatch, the growth during the first week of life appeared to be higher than in experiments with larger larvae; early growth was significantly related to size-at-hatch until 9 dph, 5 days beyond the exogenous feeding initiation. The growth and survival for the remaining period of exogenous feeding was affected by food type and concentration. Highest growth and nutritional condition (RNA/DNA) of sardine larvae, growing up to 75 dph, were obtained using high concentrations of a mixed diet, combining Gymnodinium sp., rotifers and Acartia grani nauplii. This diet guaranteed higher growth and survival than a diet based on wild planktonPeer reviewe

Effect of temperature on the growth, survival, development and foraging behaviour of Sardina pilchardus larvae

The effect of water temperature on the growth, survival, development and foraging behaviour of European sardine Sardina pilchardus larvae was examined in the laboratory. First, the capability of early sardine larvae to cope with starvation was assessed at temperatures from 10 to 22 degrees C. Second, we examined under ad libitum feeding conditions and across the range of temperatures experienced by sardines during spawning along the Atlanto-Iberian coast (13-17 degrees C) the ontogenetic changes in growth, survival and foraging behaviour of sardine larvae. Unfed larvae had similar maximum survival times (11-12 d post hatching, dph) from 13 to 15 degrees C, but the survival time was significantly shorter at the coldest and warmest temperatures tested. The survival of exogenously feeding larvae increased with temperature, but younger endogenously feeding larvae had higher survival at colder temperatures. The cumulative mortality after 25 dph, however, was similar at the 3 temperatures. Not only larval growth rate increased with increasing temperature, but ontogenetic development also occurred sooner and at smaller sizes. Notochord flexion, which is a developmental milestone for fish, occurred 10 d earlier at 17 rather than at 13 degrees C. The time spent swimming and the foraging behaviour (orientations to prey, feeding strikes and successful capture) significantly increased throughout the ontogeny and with temperature. This study highlights how even modest changes in spawning temperature can lead to large changes in the survival and growth of larval sardine. This study also reveals some of the mechanisms whereby inter-annual and seasonal variability in temperature can have significant ecological impacts at the population level

The CORALZOO project: a synopsis of four years of public aquarium science

In order to improve the methodology for growing and maintaining corals in captivity, a consortium of European zoos, aquaria and academia executed a four-year public/private collaborative research and innovation project (CORALZOO) on the breeding and husbandry of stony corals. CORALZOO comprised the following topics: (1) sexual and asexual breeding of corals in captivity, including techniques for propagation, feeding and induction of natural coral colony morphogenesis; and (2) coral husbandry: development of generic bioassays to evaluate biotic and abiotic husbandry parameters and to monitor coral health, elaboration of methods for identification and treatment of coral diseases and optimization of transport and acclimation procedures. The results of this project are reviewe