Pamela J. Schofield
Jeffrey E. Hill
William F. Loftus
Jacqueline N. Langston
2010
<p><span>The African Jewelfish (Cichlidae: </span><span class="genus-species">Hemichromis letourneuxi</span><span>) is a predatory, non-native fish that has recently (since 2000) begun to expand its geographic range across south Florida. The salinity tolerance of </span><span class="genus-species">H. letourneuxi</span><span> was unknown, and thus it was unclear whether the species could use estuarine or coastal environments. The response of </span><span class="genus-species">H. letourneuxi</span><span> to chronic change in salinity was evaluated here by exposing fish to progressively increasing salinities (0–80 ppt). Fish were held at target salinities for a minimum of 30 days. The species showed excellent survival from 0–50 ppt. At 60 ppt, only 25% of the fish survived, and mean estimated survival time was 12 days. Above 60 ppt, mortality was 100%. Fish grew equally well from 0–50 ppt. In another experiment, fish were transferred directly from freshwater to various salinities from 5–35 ppt (seawater) and held for seven days, after which survivors were returned to freshwater. All fish transferred directly from freshwater to salinities up to 20 ppt survived; only 56% survived when transferred from freshwater to 25 ppt, and none survived transfer above 25 ppt. Experimental results indicated that </span><span class="genus-species">H. letourneuxi</span><span> can persist easily in salinities prevalent in coastal environments, even during periods of hypersalinity common in south Florida estuaries. Salinity will not restrict its dispersal by coastal pathways.</span></p>
application/pdf
10.1643/CP-09-069
en
The American Society of Ichthyologists and Herpetologists
Salinity tolerance of the African Jewelfish <i>Hemichromis letourneuxi</i>, a non-native cichlid in South Florida (USA)
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