RESUMO
Seven South Pacific anguillid eel species live from New Guinea to French Polynesia, but their spawning areas and life histories are mostly unknown despite previous sampling surveys. A July-October 2016 research cruise was conducted to study the spawning areas and times, and larval distributions of South Pacific anguillid eels, which included a short 155°E station-line northeast of New Guinea and five long transects (5-25°S, 160°E-140°W) crossing the South Equatorial (SEC) and other currents. This survey collected nearly 4000 anguilliform leptocephali at 179 stations using an Isaacs-Kidd Midwater Trawl accompanied by 104 CTD casts. Based on mor-phometric observations and DNA sequencing, 74 anguillid leptocephali were collected, which in the southern areas included 29 larvae of six species: Anguilla bicolor pacifica, A. marmorata, A. australis, A. reinhardtii, A. megastoma, and A. obscura (all anguillid species of the region were caught except A. dieffenbachii). Small A. australis (9.0-16.8 mm) and A. reinhardtii (12.4, 12.5 mm) leptocephali were collected south of the Solomon Islands, other A. australis (10.8-12.0 mm) larvae were caught northwest of Fiji along with an A. obscura (20.0 mm) larva, and an A. marmorata (7.8 mm) larva was collected near Samoa. Considering collection sites, larval ages from otolith analysis, and westward SEC drift, multiple spawning locations occurred from south of the Solomon Islands and the Fiji area (16-20 days old larvae) to near Samoa (19 days old larva) during June and July in areas where high-salinity Subtropical Underwater (STUW, ~150 m depth) and the warm, low-salinity surface Fresh Pool were present. Five long hydrographic sections showed the strong Fresh Pool in the west and the STUW formation area in the east.
RESUMO
This study aims at (1) experimentally estimating first sexual maturation of the European sardine S. pilchardus, (2) using the results to calibrate existing bioenergetic models. During the 183 days-experiment, fish growth and body condition were assessed by biometry, and gonads were weighed when present. Age, wet weight and total length at first maturity were estimated at 262 days, 10.79 ± 0.75 g, and 11.26 ± 0.21 cm, respectively. Including these traits in biphasic Von Bertalanffy models did not significantly improve simulations for either length or weight data, meaning that energy allocation was not impacted by these traits. The implementation of the results in the Dynamic Energy Budget (DEB) calibration procedure strengthened the parameter set of the existing model, but resulted in significant changes in the energy allocation. Our results are a first step that will allow the design of new experiments to further quantify maturation and reproduction rates in diverse environmental conditions, consolidating DEB model calibration.
