Effects of various environmental conditions on growth and reproduction of the sea hare Aplysia oculifera (Adams and Reeve, 1850)

We studied the influences of food type, food quantity, water currents, starvation and light on growth and reproduction of the sea hare Aplysia oculifera (Adams and Reeve, 1850) under laboratory conditions. Out of five species of algae serves as food. Enteromorpha intestinalis promoted the fastest growth of A. oculifera, Ulya spp. slower growth, Cladophora sp. allowed maintenance of steady body mass, and the brown algae Colpomenia sp. and Padina pavonia were rejected by the sea hares. When sea hares were exposed to four levels of water currents, growth rates decreased as water currents increased. Sea hares fed on 50% ration grew slower than those fed on 100% ration (ad libitum). During 10 days of starvation sea hares lost weight, but when subsequently fed 100% ration they recovered and grew at a rate similar to those fed continuously with 100% ration. Under shade and under natural sunlight hares grew at the same rates. Whenever growth rates decreased, sea hares began to spawn at a smaller body size, A. oculifera demonstrated physiological plasticity that adapted them to varied and unpredictable environmental conditions. At different conditions of food availability they applied different tactics of resource allocation between growth and reproduction.