Döring, Julian; Tiedemann, Maik; Stäbler, Moritz; Sloterdijk, Hans; Ekau, Werner (2017): Reproductive parameters of Ethmalosa fimbriata as recorded in Senegal (Atlantic coast and Sine Saloum estuary). PANGAEA, https://doi.org/10.1594/PANGAEA.880051, Supplement to: Döring, J et al. (2017): Ethmalosa fimbriata (Bowdich 1825), a Clupeid Fish That Exhibits Elevated Batch Fecundity in Hypersaline Waters. 2(3), 13, https://doi.org/10.3390/fishes2030013
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Little is known about the concerted influence of temperature and salinity on the fecundity of clupeid fishes. Due to a globally changing climate, both physical parameters might act as stressors, severely affecting the reproductive potential of clupeid fish populations inhabiting tropical estuaries. Differences in relative batch fecundities, the gonado-somatic index, and the condition index of bonga shad (Ethmalosa fimbriata) were analysed in individual females sampled at the Senegalese coast and inside the inverse Sine Saloum estuary, where salinity increases upstream in all seasons.
Sampling took place at the Senegalese coast and inside the Saloum River from February to October 2014, during the peak of E. fimbriata's spawning season. An additional sampling campaign could be conducted in November 2016. Three different sites were sampled: Joal (Senegalese coast, 14°9.1' N; 16°51.7' W), Djifer (Saloum River's mouth, 13°57.8' N; 16°44.8' W), and Foundiougne (upstream Saloum River, 14°8.1' N; 16°28.1' W).
MODIS satellite-derived (Aqua, level 2, 0.1 degrees) sea surface temperatures (https://oceancolor.gsfc.nasa.gov/) were assessed at Joal (20 km radius) and Djifer once per sampling week to enhance spatial coverage by avoiding cloud cover. As no remote sensing data for inland waters were available, the Saloum River's surface water temperatures were recorded in situ once per sampling week with a digital thermometer (ama-digit ad 15 th; precision 0.4%; accuracy 0.4%). Monthly means in MODIS satellite-derived (Aquarius, level 3, 0.5 degrees) sea surface salinities (https://oceancolor.gsfc.nasa.gov/) were used to assess the coastal ocean's salinity in a radius of 20 km around Joal. For Djifer and Foundiougne salinity was measured with a handheld refractometer (Aqua Medic; precision 0.7%, accuracy 0.2%) using a Practical Salinity Scale (PSS-78).
Staging of fish was conducted macroscopically after a key by Blay Jr. & Eyeson (1982). In order to discriminate between mature females with ovaries containing fully hydrated oocytes (stage V) and females that have recently spawned (spent, stage VI) further descriptions on maturity stages in clupeid fishes were consulted (West 1990, ter Hofstede et al. 2007). Conversions of fish fork length (LF) to total length (LT) were conducted using the equation LT = 1.0007 × LF + 3.9.
In order to access the nutritional status of female fish, a condition index (CI) was calculated for each individual using wet mass (WM, ±0.1 g), total length (LT, nearest mm), and b of the length-weight relationship: CI = WM x LT ^ -3.62 x 1000.
The condition index (CI) and gonado-somatic index (GSI) of hydrated female spawners (Stage V) was based on the ovary-free body mss (OFBM, ±0.1 g) and the ovary mass (OM, ±0.0001 g): CI = WOF x LT ^ -3.62 x 1000; GSI = OM x OFBM ^ -1 x 100.
The length-weight relationship of all sampled females across all sampling sites could be described by the following function: WM = 0.0015 x LT ^ 3.62
Median Latitude: 14.108133 * Median Longitude: -16.724437 * South-bound Latitude: 13.954060 * West-bound Longitude: -16.850280 * North-bound Latitude: 14.181160 * East-bound Longitude: -16.475880
Datasets listed in this publication series
- Döring, J; Tiedemann, M; Stäbler, M et al. (2017): Fecundity of Ethmalosa fimbriata sampled within the Saloum River and at the Senegalese coast. https://doi.org/10.1594/PANGAEA.880049
- Döring, J; Tiedemann, M; Stäbler, M et al. (2017): Maturity stages of Ethmalosa fimbriata sampled within the Saloum River and at the Senegalese coast. https://doi.org/10.1594/PANGAEA.880050